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1. Field of the Invention
The invention relates to a griller, more particularly to a griller that permits setting of both the cooking temperature and the cooking time.
2. Description of the Related Art
A conventional steak griller has a pair of cooking grill members that are configured to confine a cooking space for receiving a piece of steak therein when the cooking grill members are closed together. When electric power is supplied to electric heaters of the cooking grill members, the temperature in the cooking space will rise to a preset cooking temperature and will be maintained thereat for cooking the steak piece.
A main drawback of the aforesaid conventional steak griller resides in that the user has to monitor the cooking time so that the steak piece can be cooked as desired.
Therefore, the main object of the present invention is to provide a griller that permits setting of both the cooking temperature and the cooking time so as to overcome the aforesaid drawback of the prior art.
According to the present invention, a griller comprises upper and lower cooking grill members, an electric heater unit, and a control circuit.
The upper and lower cooking grill members are coupled to each other and are configured to confine a cooking space when closed together. The cooking space is adapted to receive a piece of steak therein.
The electric heater unit is associated with the upper and lower cooking grill members and is operable so as to heat and cook the piece of steak in the cooking space.
The control circuit is connected to the electric heater unit and controls heating operation of the electric heater unit. The control circuit includes a heater controller, a sensor unit, a user input unit, a processor unit, and an alarm unit.
The heater controller is connected to the electric heater unit and is adapted to be connected to a power supply. The heater controller is operable so as control supply of electric power to the electric heater unit.
The sensor unit is adapted to detect cooking temperature in the cooking space and to generate a sensor output corresponding to the cooking temperature detected thereby.
The user input unit is operable so as to provide a cooking temperature setting and a cooking time setting.
The processor unit is connected to the heater controller, the sensor unit and the user input unit. The processor unit controls operation of the heater controller in accordance with the sensor output from the sensor unit and the cooking temperature setting from the user input unit, and generates an alarm activate signal upon detection by the processor unit that a predetermined time period corresponding to the cooking time setting from the user input unit has elapsed since the start of the supply of the electric power to the electric heater unit.
The alarm unit is connected to the processor unit and is activated by the alarm activate signal for generating an alarm output. | {
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1. Technical Field
The present invention relates to a method for arranging entities, and more particularly to a method for dynamically arranging entities within a two-dimensional workspace in a symmetrical lattice, while maximizing the distance between entities.
2. Description of Related Art
Companies displaying information on the internet or designers for such companies often need a flexible way to display dynamic groupings of information for viewing by a user on a display such as items on sale, accounts, a menu of selections, etc. Conventionally the only extant methods available for arranging this information are traditional structures, such as a list or a collection of rectangular buttons arranged in a grid. These methods often lack visual appeal, thereby detracting from a user""s attention to the information.
Additionally other areas, for example, manufacturing design, packaging design, clothing design, landscape design often utilize two-dimensional designs to plan the distribution of objects.
There are also pre-arranged patterns of other, more visually appealing shapes. However, conventional pre-arranged patterns lack the flexibility of automatically varying the size and quantities of items to fill a workspace.
Visually oriented design programs such as Visio(trademark), AutoCad(trademark) and other similar types of software have functions that allow a user to evenly distribute the spacing of objects. However, such functions only work in vertical and horizontal directions, giving no facility for uniform distribution of objects in other directions.
Many artistic or mathematical-interest computer programs offer repeated patterns of a shape through a method commonly referred to as xe2x80x9ctilingxe2x80x9d. In such programs, only one shape is involved and its form must be such that can be placed immediately adjacent to copies of itself with no intervening space in any direction.
Some mathematicians, such as Kenneth Stephenson of the University of Tennessee, have published papers on circle-packing, addressing the practice of arranging circles tangentially within various geometric shapes. The rules for packing are such that it is not always practical for display applications.
Accordingly, a continuing need exists for methods of uniformly and arranging objects in a two dimensional work space in a symmetrical lattice while maximizing the distance between adjacent entities.
It is therefore an object of the present invention to provide a method for dynamic symmetric uniform distribution of entities that does not follow a simple orthogonal grid or list arrangement, thereby providing greater visual appeal or optional arrangement of physical entities.
It is another object of the present invention to provide a method for dynamically, symmetrically, and uniformly distributing entities to facilitate the design of static arrangements, e.g. textiles, publishing, graphic arts, product design, landscape design building materials, as well as applications in which arrangements must be produced dynamically, e.g. computer displays of choices, computer displays of collections of data and to facilitate certain types of object packing for industrial or scientific applications.
To achieve the above objects and others, a method in accordance with the invention is provided which positions any number of entities (N) in rows and columns within a two-dimensional workspace, such that the center of each entity is an equal maximal distance (D) from the center of its closest neighbors, and at least half the same distance (D) from the boundaries of the area given. This distance (D) also represents the maximum diameter of the perimeter that each entity can lie completely within, without crossing another entity""s perimeter or any boundary of the workspace. The method can be utilized to achieve maximum entity perimeter/diameter or, to achieve the largest workspace possible within other known criteria, as described further hereinbelow. In most cases, the results are identical.
The workspace is an area whose edges are at a distance of D/2 from the centers of each of the outermost entities of the arrangement. Given the number of entities to be arranged (N), the dimensions of an enclosing workspace, an orientation preference (A or B), and an indication whether its primary objective is maximum entity size or maximum workspace size, the method determines the position of the center point of each entity, the diameter (D) of each entity""s perimeter, and the dimensions of the workspace. | {
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The channel used in telecommunications systems frequently causes interference in data transmission. Interference occurs in all kinds of systems but particularly in wireless telecommunications systems the transmission path attenuates and distorts the signal to be transmitted in various ways. On the transmission path interference is typically caused by multi-path propagation of the signal and different kinds of fading and reflection as well as by other signals transmitted on the same transmission path.
To reduce the influence of interference, different coding methods have been provided to protect signals from interference and to eliminate errors caused by interference in the signals. One frequently used encoding method is convolutional encoding. In convolutional encoding the signal to be transmitted and consisting of symbols is encoded into code words, which are based on the convolution of the symbols to be transmitted with themselves or with another signal. The convolutional code is defined by the coding ratio and coding polynomials. The coding ratio (k/n) means the number (n) of encoded symbols in relation to the number (k) of symbols to be encoded. The coder is usually implemented by means of shift registers. The constraint length K of the code refers to the degree of coding polynomials plus one. The coder may be regarded as a state machine with 2K-1 states.
One coding method developed from convolutional coding methods is parallel concatenated convolutional code, i.e. a turbo code. One way of forming a turbo code is to use two recursive and systematic convolutional encoders and interleavers. The resulting code includes a systematic part, which directly corresponds to symbols in the coder input, and two parity parts, which are the outputs of the parallel convolutional encoders.
A signal which has propagated on a channel is decoded in a receiver. The convolutional code can be both encoded and decoded using a trellis whose nodes (or equally states) correspond to the states of the encoder used in signal encoding and the paths between nodes belonging to two successive trellis phases of the trellis correspond to allowed state transitions between the encoder states. The code unequivocally attaches the initial and the final state of the transition, the bit under encoding and the bits of the encoding result to each state transition. The purpose of the decoder is thus to determined successive states of the coder, i.e. transitions from one state to another, which are caused by the original bits. To determine the transitions, metrics are calculated in the decoder. There are two kinds of metrics: path metrics (also state metrics) and branch metrics. The path metrics represents the probability at which the set of symbols included in the received signal leads to the state corresponding to the node in question. The branch metrics is proportional to the probabilities of transitions.
A Viterbi algorithm is usually used in decoding of a convolutional code. An example of a decoding method which requires more intensive calculation is a MAP (Maximum Aposteriori Probability) algorithm and its variations, e.g. Log MAP algorithm or Max Log MAP algorithm. The MAP algorithm is also known as a BCJR algorithm (Bahl, Cocke, Jelinik and Raviv) according to the persons who presented it first. Usually the MAP algorithm and its variations provide a considerably better result than the Viterbi algorithm. Furthermore, since the MAP algorithm and its variations are SISO algorithms (Soft Input Soft Output), they are particularly suited for iterative decoding, e.g. for decoding a turbo code where a posteriori probabilities can be utilized. The basic Viterbi algorithm is a Hard Output algorithm which has to be converted to obtain soft decisions, which increases its calculation complexity. Thus the algorithm obtained through conversion is not as good as MAP-based algorithms.
To estimate a posteriori probabilities, the MAP algorithm and its variations usually require path metrics for each bit to be decoded both from the beginning of the trellis to its end and from its end to its beginning at the bit in question. According to the prior art, the values of the path metrics of all nodes are stored in a memory in each trellis phase in respect of one direction, e.g. forwards, and then values are calculated for the other direction, e.g. backwards. The problem associated with this solution is that it requires a lot of memory because all path metrics of one direction are stored in the memory so as to allow their utilization with the path metrics to be calculated in the other direction.
U.S. Pat. No. 5,933,462, which is incorporated herein by reference, describes use of a sliding window to reduce the memory requirement. The solution comprises calculating and storing forward path metrics in respect of a window with a certain constant length and then reading them in inverse order with the backward path metrics for further measures. A solution based on the same principle is described in H. Dawid and H. Meyr: Real-Time Algorithms and VLSI Architectures for Soft Output Map Convolutional Decoding in 6th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Toronto, Canada, Volume 1, pp. 193–197, September 1995.
Another prior art solution is to use the Log MAP algorithm instead of the Max Log MAP algorithm to invert the original calculation direction of path metrics, which makes additional memory unnecessary. The solution is described in S. Huettinger, M. Breiling and J. Huber: Memory Efficient Implementation of the BCJR Algorithm in Proceedings of the 2nd International Symposium on Turbo Codes and Related Topics, Brest, France, 4–7 Sep. 2000. The problem associated with this solution is that the path metrics calculated in the inverse direction are not accurate due to the solving method used but cause errors in the values of path metrics. Furthermore, implementation of the Log MAP algorithm is more complicated than that of the Max Log MAP algorithm although the capacity of the Log MAP algorithm is slightly better than that of the Max Log MAP algorithm.
To sum up, there is a great need to solve backward processing of a trellis opposite to the actual processing direction using the memory as efficiently as possible without impairing the quality of the result. | {
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1. Field of the Invention
This invention relates to gas turbine engine exhaust nozzles and, more particularly, to seals for use between divergent flaps of axisymmetric vectorable exhaust nozzles.
2. Description of the Prior Art
Variable area axisymmetric nozzles are well known in the field and employed in such engines as the General Electric F110 engine. The exhaust nozzles of such engines use convergent divergent flaps and seals to aerodynamically control the exhaust flow to transform the pressure and thermal energy of the combustion discharge airflow into velocity and forward thrust for the engine. The manner and means to provide such nozzles are shown in many publications including U.S. Pat. Nos. 4,176,792, 4,245,787, and 4,128,208 entitled "Variable Area Exhaust Nozzle", Arthur McCardle, Jr., "Variable Area Nozzle System", Wilbert B. Freid, "Exhaust Nozzle Flap Seal Arrangement", Edward W. Ryan, et al, assigned to the same assignee and incorporated herein by reference. A new function, namely thrust vectoring, has been added to this type of nozzle as represented by an invention developed at the General Electric Company.
For an understanding of how the individual flaps and seals interrelate and operate to form the overall nozzle and thrust vectoring function, reference may be made to the patent application Ser. No. 336,369 entitled "Axisymmetric Vectoring Exhaust Nozzle", Thomas P. Hauer et al, filed with the present application and assigned to the same assignee. Interflap sealing for axisymmetric convergent divergent nozzles has always posed an interesting problem and challenge to gas turbine engine nozzle designers as evidenced by the many designs, arrangements and patents, some of which are cited herein.
Conventional nozzles including ones with variable throat and exit areas employ nozzle flaps and nozzle flap seals that pivot through the same angles or change their attitude with respect to an engine centerline generally simultaneously so there is no circumferential variation in their respective attitudes or pivot angle with respect to an engine or nozzle centerline. The axisymmetric vectoring nozzle adds a new dimension to an already difficult problem namely how to seal between two surfaces whose orientation or attitude is constantly changed. The present invention addresses the sealing problems of an interflap seal which provides sealing between two adjacent divergent flaps that are pivoted through different angles from one and other and with respect to an engine centerline. Each flap can be pivoted in a coning motion relative to the convergent flap or other other nozzle element to which it is attached. Another way of describing the problem is that there is a circumferential variation in nozzle flap attitudes with respect to an engine or nozzle centerline.
As with all nozzle and gas turbine engine system designs it is desirable that they be light weight, easy and relatively inexpensive to manufacture, maintain and repair and be highly durable in a high temperature and stress environment.
Accordingly, a primary object of the present invention is to provide sealing between nozzle flaps of a gas turbine engine axisymmetric vectoring exhaust nozzle.
Another object of the present invention is to provide sealing between the divergent flaps of a gas turbine engine axisymmetric vectoring variable exhaust nozzle.
Another object of this invention is to provide sealing between divergent flaps of a gas turbine engine axisymmetric vectoring variable exhaust nozzle wherein adjacent flaps are rotated through different angles or attitudes with respect to the nozzle centerline during vectoring operations.
Yet another object of this invention is to provide sealing between the divergent flaps which maintains axial and circumferential sealing integrity throughout the range of circumferential variation in nozzle flap attitudes with respect to the nozzle centerline.
A further object of the present invention is to provide sealing means between the divergent flaps of an axisymmetric vectoring variable exhaust nozzle which is light in weight and easy to manufacture and repair.
Yet another object of the present invention is to provide seal segments for an interflap seal for use in an axisymmetric vectoring variable exhaust nozzle that facilitate the repair and maintenance of the seal and nozzle.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings. | {
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1. Technical Field of the Invention
The present invention relates to instruction processing by a microprocessor, and more particularly, to the processing of interrupts by a microprocessor.
2. Description of Related Art
Within most microprocessors, such as micro-controllers, digital signal processors, embedded CPUs, etc., the processing of a current task (instruction set) may be stopped to enable the execution of another task related to the current task in response to some external event. The external event is commonly called an interrupt to the microprocessor. The interrupt causes the microprocessor to branch to and begin processing an interrupt service routine consisting of a number of interrupt instructions. After completion of processing of the interrupt service routine, the processor switches back to the original task and resumes processing at the point that it was interrupted.
Processors usually employ a so called pipeline structure for the execution of an instruction set defining a task. A pipeline structure refers to the division of the execution of each instruction into several stages. These stages normally comprise a fetch, decode and execute stage. The fetch stage involves retrieving the instruction from memory for execution. The decode stage involves interpreting the instruction to decide what actions are to be taken, and the execution stage involves actually executing the determined actions.
Currently used methods for processing interrupts to a processor involve branching to a location in memory where the interrupt service routine is stored. Once execution of the interrupt service routine has been completed, a branch returns processing back to where the interrupt stopped processing on the previous task. Unfortunately, the process of branching to the set of instructions defining the interrupt service routine requires the use of overhead to process the interrupt. Overhead involves the execution of clock cycles by the processor where no instructions are actually executed. The branching process requires the execution of two unused clock cycles until the first instruction of the interrupt service routine is executed. Likewise, an overhead of two clock cycles is required to branch back from the interrupt service routine to the original instruction set. Thus, a total of four clock cycles would remain unused upon the execution of each interrupt service routine. If actual processing of the interrupt service routine required only one clock cycle (a single instruction) the overhead would be 400%. Thus, some means of more efficiently processing interrupt service routines that limits overhead generated by the procedure would greatly improve the utilization of processing resources.
Another disadvantage of current systems arises from the fixed location of the code needed to execute a specific interrupt service routine. If different actions must be taken for a specific interrupt service routine depending on when the interrupt is received, the program must introduce "if-then-else" portions within the interrupt service routine code or must change the contents of the program memory for the interrupt service routine to ensure a return to the correct location. The introduction of "if-then-else" portions wastes clock cycles and memory and is thus an unacceptable solution. The changing of the contents of the program memory is a risky and impracticable solution. The fixed locations in memory of the interrupt service routines also means that if one interrupt does not require all of the space reserved in memory for that interrupt, other interrupts may not utilize the unused memory. Thus, means for more efficiently utilizing the available memory resources within a processor with respect to interrupt service routines is also needed. | {
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The progression of computing technology brings with it, at each generation, reduced size and increased performance. Hardware that once occupied a room has been reduced in size to a box, a single IC chip, or merely a portion of an IC chip. This reduction in size has brought with it corresponding packaging advances.
As an example, IBM PC compatible computers use an internal bus structure that accepts expansion cards conforming to a particular form factor. However, when these computers were reduced to the laptop, notebook, and currently palmtop sizes, the standard expansion card was too large and potentially power hungry to be elegantly integrated into this new generation of reduced size computers.
A new standard for expansion card was therefore developed for portable computing devices. Originally known as "IC Cards", later renamed "PCMCIA cards" (i.e., Personal Computer Memory Common Interface Architecture) and most recently renamed "PC Cards", these cards adhere to well defined physical and electrical standards such that they are compatible with a variety of products from different vendors. These cards will be referred to herein as "PCMCIA" cards.
Although technology has brought with it size reduction of components, space within PCMCIA cards remains limited, especially in view of the functional demands placed thereon by customers. Therefore, many problems have been encountered in designing PCMCIA cards with all the technology and features demanded of them, while still conforming to the tight physical space limitations thereof.
One particular set of problems is related to the program storage devices for processors on-board PCMCIA cards. In order for the PCMCIA card processor to initially boot-up when powered, there must be some program loaded within the on-board program storage device. Conventionally, non-volatile storage devices of the rewriteable or one-time-programmable type have been used to hold programming for the card. These devices are typically soldered to the PCMCIA card, since sockets are unreliable, costly, and too large for most PCMCIA applications. The storage devices are often programmed before they are soldered to the PCMCIA printed circuit board.
Programming the program storage devices before "solder down" introduces many problems. For example, additional manufacturing steps are needed to program, test and track the devices. Any added steps in manufacturing add a corresponding cost. Further, if software updates are performed between programming and product shipment, reprogramming is needed. This again adds costs. Moreover, if the storage device was one-time programmable, it must be thrown away, an even more expensive undertaking (especially if it has already been soldered to the board, and must be unsoldered and replaced).
Along with problems related to the programming of the program storage devices, conventional techniques introduce problems in the amount of storage available in such devices. For instance, in the case of one-time programmable devices, any diagnostic code is preloaded therein. This reduces the amount of space available for applications code. A compromise is therefore struck, and limited diagnostics typically results. This increases repair costs.
In the case of reprogrammable program storage devices (for example, flash memory) at least some loader and reconfiguration code is required within the storage device to facilitate an initial load (and reload) of code. Again this takes valuable storage space away from applications code.
By way of further background, previous non-PCMCIA systems have been implemented where a first processor loads a memory shared with a second processor which then boots therefrom. However, these systems have not been configured with an industry standard interface between the processors, let alone a PCMCIA interface. Thus, these previous systems have not had to provide all communications and control necessary to boot from a shared memory, while still adhering to a strictly defined set of standardized communications and control signaling.
The present invention is directed toward solutions to the above-noted problems. | {
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Radon (Rn-222) denotes a radioactive nuclide generated by the disintegration of uranium-series radium (Ra-226) and its half-life period is 3.824 days. Thoron (Rn-220) denotes a radioactive nuclide generated by the disintegration of thorium-series radium (Ra-224) and its half-life period is 55.6 seconds. These elements are both an inert gas and these origins are uranium (U-234) and thorium (Th-232) which occur in the earth crust, respectively.
Radon and thoron which have been generated in the earth crust are in the form of gas and therefore they leach out of the ground to the earth's surface or emerge on the ground together with groundwater. Then, if air ventilation is poor in highly airtight houses, insides of tunnels, underground shopping areas or the like, concentrations of radon and thoron reach a high level in some cases. The radiation exposure to which general public are subjected from the natural world in a year is said to be about 2.4 mSv. The exposure of a lung to the radiation caused by radon, thoron and their daughter radionuclides is said to account for approximately half of the exposure of 2.4 mSv. Accordingly, effects of the exposure due to these nuclides on a human body are concerned.
By the way, with respect to a method for measurement of airborne radon and thoron, an ionization chamber method, a scintillation cell method, an electrostatic collection type chamber method, a filter method and a still-standing-type measurement method have been presently put into practical use.
According to the ionization chamber method, a chamber with a capacity of 1 to 300 L is employed, and the method includes two, i.e., a method by measuring an ionized current and a method for measuring by using pulse. In order to increase the detection sensitivity of the methods, the capacity of the chamber should be enlarged and therefore the methods are unsuitable to perform high sensitive measurement in the field. Hence, the methods are often utilized as a measuring instrument for calibration. Consequently, in general, it is difficult to separately measure radon and thoron, using the methods.
According to the scintillation cell method, a device is employed which comprises a chamber having an inner wall to which fluorescent materials (ZnS:Ag) are applied and a photomultiplier tube connected optically to the chamber. Its measurement accuracy is proportional to a cell volume. When the cell volume is large, however, light from the fluorescent material becomes unable to reach the photomultiplier tube, thus putting restrictions on the cell volume. Further, unless radon concentration is comparatively high, it cannot be measured. Consequently, in general, radon and thoron are difficult to separately measure.
According to the electrostatic collection type chamber method, a spherical, hemispherical, or cylindrical chamber is employed. A mylar thin film is laid on a chamber bottom and a negative voltage is applied thereto, while a positive voltage is applied to a chamber wall. Polonium (Po-218), a daughter radionuclide of radon, is caught on the mylar film and detected. Radon and thoron can be separately measured but the measurement is strongly affected by humidity.
According to the filter method, the daughter radionuclides of radon and thoron which are in the atmosphere are collected directly on a filter to measure α rays emitted from the daughter radionuclides. In this method, radon is not directly collected and hence the equilibrium between radon and its daughter radionuclides must be estimated and the estimation could be an error factor. Further, according to the two-stage filter method, lowering of a measurement value due to the wall loss effect of the daughter radionuclides inside the chamber will pose a problem.
According to the still-standing (passive)-type method, resin such as polycarbonate or the like is laid as a detector inside a measurement container made of metal or the like. After having been atmospherically exposed for a preset period of time, the resin inside the detector is chemically etched to measure radon from α ray's solid state tracks developed there. The device used for this method is small-sized and hence a large number of the devices can be laid simultaneously at many measurement points and besides radon and thoron can be discriminated by using a filter or the like. Its detection sensitivity, however, is low and therefore the device needs to be atmospherically exposed typically for two moths or more. For the sake of reproducibly developing the solid state tracks, the chemical etching condition should be strictly controlled.
Other known prior art references are:
Japanese unexamined patent publication No. H6-258443; Japanese unexamined patent publication No. H6-258450; Japanese unexamined patent publication No. H8-136660; Japanese unexamined patent publication No. H8-136661; Japanese unexamined patent publication No. H8-136662; Japanese unexamined patent publication No. H8-136663; and Japanese unexamined patent publication No. H8-201523.
As described above, various types of measurement methods have conventionally been put into practical use as the radon and thoron measurement methods. Either method, however, have had some sort of problems.
Therefore, in view of the problems set forth above, it is an object of the present invention to provide a novel method for measuring airborne radon and thoron in which a measurement device structure is small-sized and which is free of the influence from its measurement environment. | {
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This invention relates to a device for selecting the hooks of a shed-forming device for a weaving machine, comprising a number of upwardly and downwardly movable hooks and, for each hook, a selection element with which the hook can be selected in order to be held by a holding element at a selection height and a returning means in order to exert a downward directed returning force on a contact part of the hook that is lower than the top hook extremity, only in the course of a part of the movement path of the hook.
This invention also relates to a shed-forming device provided with a number of these selection devices, more specifically a jacquard machine, as well as a weaving machine provided with such a shed-forming device.
When weaving on a weaving machine, in successive operating cycles of the weaving machine, one or several weft yarns are inserted in a shed between warp yarns. The insertion of weft yarns occurs in each case at well-defined weft insertion levels. In the course of the weaving, in each operating cycle, the various warp yarns have to be brought into a predetermined position in relation to each weft insertion level in order to obtain the desired fabric. Devices with which warp yarns can automatically be correctly positioned in the course of weaving on a weaving machine, are generally known. In the claims and the specification of this patent application such a device is called a shed-forming device.
Jacquard machines with which the warp yarns can be positioned individually or in groups in the course of weaving on a weaving machine, are known. A known jacquard machine comprises a number of shed-forming devices with two knives moving up and down in opposite phase that can each engage a series of hooks. For this purpose each hook has a supporting nose that is provided in order to rest on a supporting edge of a knife. This machine furthermore also comprises a number of selection elements with solenoids with which each hook can be brought into a position whereby a hook-shaped projection provided at a fixed height arrives in an opening of the hook, so that this hook remains hanging at a selection height during the further movements of the knives. This hook is then selected. The hook can remain selected during several operating cycles of the knives, but can also be already released on the following movement cycle of the knives by a suitable control of the selection element in question, whereby the hook-shaped projection no longer meshes in the opening of the hook, and whereby the hook again rests with its supporting nose on a knife and moves downward with the knife.
The movements of the hooks can, for example with pulley devices, be transmitted to harness cords, which in their turn are connected to jacquard heddles that can more one or several warp yarns. By selecting hooks or not the jacquard heddles, and therefore also the warp yarns, can be brought into two or more different positions. The selection elements can for example be electronically operated in order at each operating cycle of a weaving machine, to obtain a correct positioning of the warp yarns, through a suitable hook selection.
A jacquard heddle is lifted upward by a jacquard hook that rests on an upward moving knife. When a jacquard heddle has to be brought to a lower situated position a jacquard hook working together therewith will follow the downward movement of a knife. In order to hold each hook on the knife with these up and down movements, each jacquard heddle is connected to a return spring that exerts a downward directed force on the jacquard heddle.
With selection of a hook it is of great importance that the hook is brought to the correct height at the right moment in order to be able to implement this selection without any problem, and that the hook, after implementing the selection, hooks in well on the hook-shaped projection, or, in case of non-selection thereof, moves down again on a knife. The spring force acting on the jacquard heddles often appears to be insufficiently effective for this purpose. A number of devices are known with which it has been attempted to remedy this. These devices have the characteristics that are mentioned in the first paragraph of this specification.
A first known device is the one according to the patent publication DD 283 429. In this device a second return spring is provided for safely bringing the hook to the selection position were for one reason or another the first return spring (that acts on the jacquard heddle) not to do this, e.g. knots entangling in the warp yarns. This device also has the great disadvantage that a second spring has to be compressed over the total lifting height of the hooks. The drive of this device will therefore consume a higher power.
A second device is known from patent publication EP 0 408 076. With this device a pressure bar is provided that only presses on the hooks if these are in the top part (in the vicinity of their top dead point) of their movement path. The weight of the pressure bar is sufficient in order to prevent the hook from leaving the knife upon reaching the top dead point of the movement, and in order to press downward a magnetically attracted hook against the friction, until it hangs on the projection, even were the return force acting on the jacquard heddles have failed entirely. This device has the characteristics mentioned in the first paragraph of this specification but has as disadvantage that the removal of a hook is rather time-consuming and that the device is not suitable for high weaving speeds.
Another solution is known from patent publication EP 0 823 501. This device can only operate with jacquard machines with rather thick-walled form-retaining plastic hooks.
The purpose of this invention is to provide a hook selection device with which the above described disadvantages are remedied, and with which therefore an operationally safe hook selection can be implemented at relatively high weaving speeds, whereby the hooks are removable, and whereby the hook selection device requires very limited additional power.
In particular by an operationally safe hook selection a selection is meant that is implemented without any problem and continues to be maintained, even were the return force of the jacquard heddle would be reduced temporary or cease entirely.
This purpose is achieved according to this invention by providing a hook selection device with the characteristics mentioned in the first paragraph of this specification, of which each returning device comprises a pressure means that can be moved upwards by a hook against a downward directed spring load.
If a resetting force is exerted on the top hook extremity, a non-form-retaining hook will deform under the influence of this force and the hook selection will fail. By applying a smaller return force the chance of deformation of the hook is reduced but the smaller return force therefore also becomes less effective.
If however the return force makes contact on a lower situated contact part of the hook, the point of application of the return force acting on the hook will lie either at a shorter distance above the supporting nose of the hook or below this supporting nose. The power of the forces acting on a hookxe2x80x94namely the downward directed return force and the upward directed pushing force of the knife on which the hook rests applied to the supporting nosexe2x80x94in order to deform the hook decreases because of this, so that an effective return force can also be acting on non-form-retaining hooks without risk of an undesired deformation of the hook. In contrast to a number of known devices this selection device is therefore very well suited for use with hooks that are not form-retaining. Such hooks are usually made out of metal and are among others used with selection devices that operate with solenoids, whereby the hooks have to be capable of being bent under the influence of a magnetic attractive or repulsive force developed by a solenoid in order to come into a selection position or a non-selection position.
Since the return force only has to be acting during a limited part of the movement path of the hooks, the selection device can be so implemented that the hooks are easily removable. The hooks also only have to be moved during a limited part of their movement path against the return force so that the additional power that is consumed by this device is minimal.
This selection device also ensures a very operationally safe selection. Through the return force the hooks are prevented from leaving the knife at the moment that they can be selected and it is ensured that the holding means provided on the hook is correctly positioned in relation to the holding element. This is especially necessary where the hooks can be selected in the vicinity of the top dead point of their up and down movement. After the selection has been implemented and the holding element in co-operation has come with the holding means provided on the hook (e.g. if the hook is brought into a bent position by the selection element, so that a hook-shaped projection provided at a fixed height latches in a window opening of the hook), the return force ensures that the hook with the downward movement of the knife is pressed downward over a short distance, so that the co-operation between holding element and holding means is improved. Where the holding element and holding means are respectively implemented as a projection and an opening (of vice versa) this results in the correct hooking-up of the hook.
The return force continues to be maintained as long as the hook remains hooked up. A temporary interruption in the downward force exerted on the jacquard heddle will therefore not lead to a hook falling off. When a hook is no longer selected, the returning force will also ensure that the xe2x80x9cstick-slipxe2x80x9d effect is better overcome and that the hook at least starts to follow the downward movement of the knife.
Once in movement the force acting on the jacquard heddle must be sufficient in order to hold the hook on the knife during the remainder of the downward movement.
Because of the fact that each return device comprises a pressure means, which is upwardly movable by a hook against a downward directed spring pressure, the selection device is very reliable and is less subject to wear and tear than the known devices.
Because of this the device can also operate at a very high speed and the pre-tensioning of the resetting springs in the harness (that exerts a downward directed spring pressure on the jacquard heddles) is reduced. This leads to a saving in the drive power of the jacquard machine.
The hook selection device according to this invention is preferably so implemented that the aforesaid contact part of each hook lies lower than the holding means with which a holding element can work together in order to hold the hook at the selection height. The deforming power of the forces acting on a flexible hook is still further reduced because of this so that the device can work operationally safely with hooks with a great flexibility.
Each return device can be provided for that purpose with a pressure means that, only in the course of the upward movement of this hook, can be moved upward on a top part of its movement path. Because of this the return force is acting on the hooks when these are in the top dead point of their up and down movement. Because of this the hooks are prevented from leaving the knife in that top dead point through their inertia, and not being correctly positioned in relation to the holding element and/or the selection element.
In a preferred embodiment of the hook selection device according to this invention each return device comprises a guide for guiding the pressure means in the course of its up and down movements.
A particularly simple and effective embodiment is obtained if the aforesaid guide comprises a guiding wall that to a great extent encloses the pressure means, while the aforesaid contact part of the hook in the course of the up and down movements of the hook extends inside the guiding space enclosed by the guiding wall, so that the contact part can take the pressure means along upward.
Each return device can for example comprise a spring disposed between the top of the pressure means and an immovable bearing surface that exerts a downward directed spring pressure on the pressure means. This spring is preferably provided in a top part of the guiding space.
The hooks can be of very simple design if the contact part is a lateral projection of the hook that is at the same time provided in order to rest on a lifting means. The hooks need not then be provided with a separate contact part.
Each hook can be so implemented that it comprises a supporting nose that is provided in order to rest on a lifting means, while the contact part of each hook is a(nother) lateral projection of the hook, whereby this supporting nose and this contact means are provided opposite each other on either side of the hook.
Preferably, the hooks are provided in order to be bent under the influence of a force exerted by a selection element.
In a particular embodiment each return device is provided in a lower part of a guide housing for the jacquard hooks. The device is most effective when a return device is provided for each hook.
A shed-forming device, in particular an electronically operated jacquard machine, which is provided with or works together with a hook selection device according to this invention, as well as a weaving machine provided with such a shed-forming device, falls within the scope of protection determined by the claims of this patent application.
In the following detailed specification of an embodiment example of a hook selection device according to this invention the aforesaid characteristics and advantages of the invention are further explained and additional properties and advantages thereof are indicated. The purpose of this specification is only to give a clarifying example of a possible embodiment of this invention and can therefore in no way be interpreted as a restriction on the field of application of the invention or on the patent rights claimed in the claims.
In this specification reference is made by means of reference numbers to the figures attached hereto, of which | {
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In the plastic injection molding art, the usual challenges facing a product designer is to design an article having requisite strength for the product application and uniform surface quality for satisfactory appearance, but to avoid excessive weight, material usage and cycle time. A design compromise must often be made between strength and plastic thickness. A relatively thicker plastic section in the article, such as a structural rib, will incur greater weight, material usage, cycle time and induce sink marks and other surface defects due to thermal gradients in the area of the thickened section.
It is known in the plastic molding art to use pressurized fluid in conjunction with the plastic molding of articles as shown in U.S. Pat. No. 5,098,637 to Hendry. The pressurized fluid is typically nitrogen gas which is introduced into the mold cavity at or near the completion of the plastic injection. The pressurized fluid serves several purposes. First, it allows the article so formed to have hollow interior portions which correspond to weight and material savings. Second, the pressurized fluid within the mold cavity applies outward pressure to force the plastic against the mold surfaces while the article solidifies. Third, the cycle time is reduced as the gas migrates through the most fluent inner volume of the plastic and replaces the plastic in these areas which would otherwise require an extended cooling cycle. Fourth, the gas pressure pushes the plastic against the mold surfaces, thereby obtaining the maximum coolant effect from the mold.
However, as the dimensions of the molded article increase, the gas must do more work to migrate through the volume of the mold cavity to assist in setting up the article within the cavity. If the pressure of the gas is too great as it enters the mold cavity, there is a risk that it may rupture or blow out the plastic within the mold cavity, i.e., the gas is not contained within the plastic. Thus, there have been practical limitations in the adaptation of gas injection in the plastic molding field.
The above-noted U.S. patent to Hendry solves most of these problems.
As illustrated in FIGS. 1-4, another approach is to use a fixed volume spill cavity 24 with a block pin 20 and shims 26 to control the volume of plastic going into the spill cavity 24.
In FIG. 1, the pin 20 is in its up position blocking plastic flow from the molding in the article-defining cavity 12, through a runner 23 and into the spill cavity 24. In FIGS. 2-4, the pin 20 is in its down position allowing plastic to go to the spill cavity 24 by the pressure of the gas.
However, injection molding machines do not deliver the same quantity of plastic shot after shot. When doing straight compact injection molding, the cushion of plastic in front of the screw after the mold is full and the high pressure packing starts, takes care of this inaccuracy of the screw ram to deliver the same quantity of plastic on each shot (i.e., the cushion can fall from 10 mm to 5 mm with no difficulty in molding the compact injection molding).
However, with some parts, one does not want to pack the molding. One wants to just fill the cavity. If one packs the molding, a strain pattern will already be in place within the molding and the hollowing out of the part will not relieve the strain already in place in the molding.
FIG. 2 illustrates blow out in the spill cavity 24 causing a loss of gas pressure in the molding the article defining cavity 21. One result of this is a possible shrinkage due to loss of gas pressure in the molding in the article defining cavity 21. Also, gas leakage may occur at the mold parting line.
FIG. 3 illustrates the use of too much plastic which would result in sink marks at reference numeral 26.
Finally, FIG. 4 illustrates the addition of the shims 26. However, overpacking and blow out as illustrated in FIGS. 3 and 2, respectively, can still occur. | {
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1. Technical Field
This invention relates to telecommunications services for providing caller identification information to a called party and, more particularly, to a self-provisioning names database for such services.
2. Description of the Relevant Art
Over the years caller services have increased due to the computerization of telecommunications services. For example, one such service that is now provided to telecommunications subscribers is caller identification. As a caller places a telecommunications call to a called party and enters address signaling data for signaling the called party, both the calling party's telephone number and the called party's telephone number are transmitted to the telecommunications switch, typically a Lucent Technologies #5ESS electronic switch, serving the called party. As the called party's line rings, the switch serving the called party also provides data to the subscriber loop or trunk to the subscriber's premises which can actuate a display to display the calling party's telephone number at the called party's premises.
Since the introduction of the caller identification service by telephone number, local operating telephone companies have also offered a related service for providing the name of the calling party. Subscribers to such a service are provided a display of both the telephone number and name of the calling party for an extra fee. The local operating telephone company will generate a query during a call of a remote billing database, for example, a database maintained by the operating telephone company serving the calling party, to perform a number to name translation and forward the name data to the calling party along with the telephone number for display. Others besides the operating telephone companies may maintain a similar database that may attempt to maintain a names list, for example, for all the telephones in an entire country or region thereof. Of course, any such entity may charge for access to such a regional or national database that it maintains.
A problem persists, however, in that in providing such name identification services, the local operating telephone companies must rely on other telephone companies or national database access providers to provide the name information. Also, the information may not be provided in time to be signaled via a subscriber's display before the subscriber must answer the phone. Finally, the costs of providing such a service may become high in relation to the perceived value to the customer. Consequently, there remains a need in the art to provide a caller identification by number and name service that is economical and efficient. | {
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Android, as an open operating system, has been increasingly widely used in terminal devices. With gradual increase of application programs, for a terminal device (for example, an Android smart phone) using an Android operating system, to operate, in a more convenient and quick manner, application programs installed on the terminal device, a multi-screen desktop design is used for an existing terminal device using an Android operating system. The multi-screen desktop design means that a desktop is divided into several desktop screens, where each desktop screen is used to display a desktop object, one desktop screen is a one-screen desktop, and multiple desktop screens form a multi-screen desktop. The desktop object refers to an object that needs to be displayed on the desktop, and the desktop object includes but is not limited to a shortcut icon of an application program, a file, a folder, and the like. In the terminal device using a multi-screen desktop design, how to sort desktop objects on a multi-screen desktop is a difficulty to be resolved for the existing terminal device using a multi-screen desktop design.
An existing method for sorting desktop objects is generally setting a desktop object in a first location to a draggable state first, and then dragging the desktop object in the first location to a second location, so as to achieve an objective of moving the desktop object from the first location to the second location. For a terminal device using a multi-screen desktop design, this manner has problems of a complex operation, high time consumption, and a high locating error rate. If an application program icon A on a first desktop screen is to be moved to a blank area on a fifth desktop screen, it is required to touch and hold down the application program icon A to set the application program icon A to a draggable state; drag the application program icon A to a screen edge, so as to drag the application program icon A from the first desktop screen to a second desktop screen; and continue to drag the application program icon A that has been dragged to the second desktop screen to a screen edge, so as to drag the application program icon A from the second desktop screen to a third desktop screen. By analogy, the application program icon A can be dragged to the fifth desktop screen only after four times of desktop screen switching are performed; and finally, the application program icon A is released in the blank area on the fifth desktop screen, so that the application program icon A on the first desktop screen can be moved to the blank area on the fifth desktop screen. For another example, if locations of an application program icon A and an application program icon B are to be exchanged, it is required to first touch and hold down the application program icon A to set the application program icon A to a draggable state, drag the application program icon A to a blank area, and then drag the application program icon B to a start location of the application program icon A; and finally, move, to a start location of the application program icon B, the application program icon A that has been dragged. After the foregoing processes end, location exchange of application program icons is complete. | {
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1. Field
Example embodiments relate to a three-dimensional (3D) face capturing apparatus, method and computer-readable medium.
2. Description of the Related Art
Today's users are not satisfied with two-dimensional (2D) information. Users demand new experiences associated with a human interface, a natural game control, a 3D display, and the like. Accordingly, superior 3D contents and 3D facial information may be demanded.
A laser scanner may be a general and convenient apparatus for capturing a 3D target object. A 3D surface may be accurately obtained using the laser. Some researchers have also attempted to capture the 3D face using a single camera or a plurality of cameras.
U.S. Pat. No. 6,556,196, titled ‘Method and Apparatus for the Processing of Images’, discusses a 3D face being formed from a 2D image. The patent discusses modeling of a 3D face using a 2D image based on a morphable object model. A shape of a model is learned based on various accurate 3D face models obtained using the laser scanner. A 3D face may be expressed based on a Principal Component Analysis (PCA) coefficient and the PCA coefficient may be calculated by minimizing a difference between a 3D face projection and an input image. However, U.S. Pat. No. 6,556,196 uses only 2D images and thus, a reconstruction of the 3D face is unreliable. Also, the U.S. patent may use a manually marked feature point and may expend much time for calculation.
U.S. Patent Application US20090052748, titled ‘Method and System for Constructing a 3D Representation of a Face from a 2D Representation’ discusses that a 3D face is reconstructed using a single neutral frontal face image. Partially inputted facial features may be detected from a 2D input image. As a result, a difference between input features and composed 3D face features may be minimized.
However, U.S. Patent Application US20090052748 may have a limit in inputs. The 3D face is reconstructed from the single face image and thus, the reconstructed 3D face may be unreliable.
Although a 3D face reconstructed based on a laser scanner is very accurate, there are a variety of problems. First, the interface is not sufficiently good for the 3D face reconstruction. Second, scanning is mechanically processed and as a result much time may be expended. Third, the person being scanned may be immobile while their head is scanned. Also, some users believe that the laser is harmful to human eyes. In addition, the laser scanner is too expensive to be widely used.
A method of modeling a 3D face based on an image is unreliable compared with the modeling using the laser scanner. The method of modeling a 3D face based on an image may incur a high cost and a long calculation time. Also, the method of modeling a 3D face based on an image may not realize a reliable and accurate 3D face model. To obtain an ideal result, the method of modeling a 3D face based on an image may have a feature point manually marked. The method may use a facial 3D image and a 2D pattern PCA model. The model may be trained using a 3D face database of the laser scanner and thus, the method is complex. | {
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When network packet arrives at a typical network interface card (NIC), the NIC moves the data into pre-allocated network buffers in system main memory. From there the data is read into the CPU cache so that it can be checksummed (assuming of course that the protocol in use requires checksums. Some, like IPX, do not.). Once the data has been fully processed by the protocol stack, it can then be moved into its final destination in memory. Since the CPU is moving the data, and must read the destination cache line in before it can fill it and write it back out, this involves at a minimum 2 more trips across the system memory bus. In short, the best one can hope for is that the data will get moved across the system memory bus 4 times before it arrives in its final destination. It can, and does, get worse. If the data happens to get invalidated from system cache after it has been checksummed, then it must get pulled back across the memory bus before it can be moved to its final destination. Finally, on some systems, including Windows NT 4.0, the data gets copied yet another time while being moved up the protocol stack. In NT 4.0, this occurs between the miniport driver interface and the protocol driver interface. This can add up to a whopping 8 trips across the system memory bus (the 4 trips described above, plus the move to replenish the cache, plus 3 more to copy from the miniport to the protocol driver). That's enough to bring even today's advanced memory busses to their knees.
In all but the original move from the NIC to system memory, the system CPU is responsible for moving the data. This is particularly expensive because while the CPU is moving this data it can do nothing else. While moving the data the CPU is typically stalled waiting for the relatively slow memory to satisfy its read and write requests. A CPU, which can execute an instruction every 5 nanoseconds, must now wait as long as several hundred nanoseconds for the memory controller to respond before it can begin its next instruction. Even today's advanced pipelining technology doesn't help in these situations because that relies on the CPU being able to do useful work while it waits for the memory controller to respond. If the only thing the CPU has to look forward to for the next several hundred instructions is more data moves, then the CPU ultimately gets reduced to the speed of the memory controller.
Moving all this data with the CPU slows the system down even after the data has been moved. Since both the source and destination cache lines must be pulled into the CPU cache when the data is moved, more than 3 k of instructions and or data resident in the CPU cache must be flushed or invalidated for every 1500 byte frame. This is of course assuming a combined instruction and data second level cache, as is the case with the Pentium processors. After the data has been moved, the former resident of the cache will likely need to be pulled back in, stalling the CPU even when we are not performing network processing. Ideally a system would never have to bring network frames into the CPU cache, instead reserving that precious commodity for instructions and data that are referenced repeatedly and frequently.
But the data movement is not the only drain on the CPU. There is also a fair amount of processing that must be done by the protocol stack software. The most obvious expense is calculating the checksum for each TCP segment (or UDP datagram). Beyond this, however, there is other processing to be done as well. The TCP connection object must be located when a given TCP segment arrives, IP header checksums must be calculated, there are buffer and memory management issues, and finally there is also the significant expense of interrupt processing, discussed below.
A 64 k server message block (SMB) request (write or read-reply) is typically made up of 44 TCP segments when running over Ethernet, which has a 1500 byte maximum transmission unit (MTU). Each of these segments may result in an interrupt to the CPU. Furthermore, since TCP must acknowledge (ACK) all of this incoming data, it's possible to get another 44 transmit-complete interrupts as a result of sending out the TCP acknowledgements. While this is possible, it is not terribly likely. Delayed ACK timers allow us to acknowledge more than one segment at a time. And delays in interrupt processing may mean that we are able to process more than one incoming network frame per interrupt. Nevertheless, even if we assume 4 incoming frames per input, and an acknowledgement for every 2 segments (as is typical per the ACK-every-other-segment property of TCP), we are still left with 33 interrupts per 64 k SMB request.
Interrupts tend to be very costly to the system. Often when a system is interrupted, important information must be flushed or invalidated from the system cache so that the interrupt routine instructions, and needed data can be pulled into the cache. Since the CPU will return to its prior location after the interrupt, it is likely that the information flushed from the cache will immediately need to be pulled back into the cache. What's more, interrupts force a pipeline flush in today's advanced processors. While the processor pipeline is an extremely efficient way of improving CPU performance, it can be expensive to get going after it has been flushed. Finally, each of these interrupts results in expensive register accesses across the peripheral bus (PCI).
We noted earlier that when the CPU has to access system memory, it may be stalled for several hundred nanoseconds. When it has to read from PCI, it may be stalled for many microseconds. This happens every time the CPU takes an interrupt from a standard NIC. The first thing the CPU must do when it receives one of these interrupts is to read the NIC Interrupt Status Register (ISR) from PCI to determine the cause of the interrupt. The most troubling thing about this is that since interrupt lines are shared on PC-based systems, we may have to perform this expensive PCI read even when the interrupt is not meant for us.
Other peripheral bus inefficiencies also exist. Typical NICs operate using descriptor rings. When a frame arrives, the NIC reads a receive descriptor from system memory to determine where to place the data. Once the data has been moved to main memory, the descriptor is then written back out to system memory with status about the received frame. Transmit operates in a similar fashion. The CPU must notify that NIC that it has a new transmit. The NIC will read the descriptor to locate the data, read the data itself, and then write the descriptor back with status about the send. Typically on transmits the NIC will then read the next expected descriptor to see if any more data needs to be sent. In short, each receive or transmit frame results in 3 or 4 separate PCI reads or writes, not counting the status register read. | {
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Patent Document 1 discloses an imaging apparatus system configured by an interchangeable lens and a camera body. In the imaging apparatus system, the interchangeable lens includes a focus lens drive motor and a zoom lens drive motor. Control of these motors, and so on, is performed in synchronization with a vertical synchronizing signal for video supplied from the camera body. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to a heat exchanger having header tubes. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device.
2. Description of the Related Art
A ferroelectric memory using a ferroelectric film such as a Pb(ZrxTi1-x)O3 film (a PZT film) for a dielectric film of a capacitor, i.e., a FeRAM (ferroelectric random access memory) has recently been developed.
The ferroelectric memory has a problem that a capacitor decreases in characteristics and reliability because of a diffusion of hydrogen into the capacitor. For example, a step of patterning a capacitor film by RIE and a step of forming an interlayer insulating film by CVD after forming the capacitor are carried out in a gaseous atmosphere containing hydrogen. A hydrogen barrier film therefore needs to prevent hydrogen from diffusing. A conventional ferroelectric memory had two problems because no adequate measures were taken against a diffusion of hydrogen.
The first problem is as follows. A silicon nitride film is known as one hydrogen barrier film (see Jpn. Pat. Appln. KOKAI Publication No. 2001-15698, for example). Conventionally a silicon nitride film was formed in a gaseous atmosphere containing hydrogen such as SiH4 and thus a diffusion of the hydrogen caused a problem.
The second problem is as follows. Conventionally a hydrogen barrier film was formed chiefly only around a capacitor. To form a hydrogen barrier film only around a capacitor is not always adequate measures against a diffusion of hydrogen because the hydrogen barrier film cannot shut off the hydrogen completely. A ferroelectric memory generally has a multilevel interconnect structure that is obtained by repeatedly forming an interlayer insulating film and a wiring layer after a capacitor is formed. Since most interlayer insulating films are formed in a gaseous atmosphere containing hydrogen, it is necessary to take measures to effectively prevent the hydrogen from diffusing. Jpn. Pat. Appln. KOKAI Publication No. 2001-15703 discloses a structure in which a hydrogen barrier film is formed between interlayer insulating films. However, the structure of the Publication aims at resolving a problem with hydrogen annealing and takes into no consideration a diffusion of hydrogen occurring when an interlayer insulating film is formed in a multilevel interconnect structure. It is thus difficult to exactly prevent a diffusion of hydrogen due to the formation of interlayer insulating films.
As described above, conventionally, no adequate measures were taken against a diffusion of hydrogen. No capacitors that improved in characteristics and reliability were difficult to achieve. | {
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This invention relates in general to induction heating of elongated metal workpieces and, more particularly, to a method and apparatus for inductively heating to a uniform surface temperature an elongated workpiece having an extended intermediate portion of uniform cross-section and relatively short, axially spaced, end or other portions of enlarged cross-section.
The invention is particularly applicable to the heating of so-called sucker rods which are employed in oil wells and the like and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be used for inductively heating a variety of elongated workpieces having an intermediate portion of substantially uniform cross-sectional shape extending between axially spaced portions of enlarged cross-sectional shape.
Sucker rods are utilized in the petroleum industry as a connecting link between a down hole oil well pump and the lifting or pumping device on the surface. Each rod is quite long, normally being of the order of magnitude of 25-30 feet in length. A major portion of the length of the rod, hereinafter referred to as the intermediate or central bar portion of the rod, has a uniform cross-section which may be of circular, hexagonal, or the like cross-section and is generally uniform over its entire length. At their opposite ends, the rods are provided with comparatively short enlarged or upset end portions for facilitating interconnection of a plurality of the rods together in end-to-end relationship with each other. While there are a number of specific or detailed modifications which may be included in the sucker rod configurations of different manufacturers, almost all such rods have the foregoing general conformation and characteristics.
As one of their manufacturing steps, the sucker rods are usually heated to a given predetermined surface temperature and then passed through an electrostatic spray chamber for application of a coating of paint or plastic-like material thereto. Since the rods need only be surface heated for this purpose, induction type heating finds particular use in this environment. However, because sucker rods do not have uniform cross-sections throughout the entirety of their length, it is necessary to in some way compensate for the heating variations which otherwise occur at the enlarged or upset end portions. Unless each rod is heated to a uniform surface temperature over the entire length thereof, the paint of plastic-like coating subsequently applied to the rods will not have a uniform consistency, thickness, etc. thereon, particularly as between the elongated central bar portions and the enlarged ends.
A number of different arrangements to compensate for this difficulty have been previously proposed and employed heretofore. Such solutions include voltage regulation for the inductor, delay on or off timers, various alternative inductor configurations and the like. However, none of these proposed or previously employed arrangements have satisfactorily solved the problem of uniformly heating the surface of sucker rods or other similar elongated workpieces having sections of enlarged cross-section at their opposite ends.
It has been considered desirable, therefore, to devise an improved induction heating arrangement for sucker rods or similar workpieces which facilitates induction heating thereof to a substantially uniform surface temperature throughout the entire length of the rods. The method and apparatus described herein is deemed to provide such an improved heating arrangement which satisfactorily overcomes the foregoing problems and others. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to a discharge and light emitting device in which a discharge gas such as xenon enclosed between electrodes is discharged for emitting light.
2. Description of the Background Art
Various light emitting devices have been proposed and reduced to practice as a light source. One of such conventional devices is a light source used for a contact image sensor (hereinafter as CIS) which reads a content such as diagram.
FIGS. 11 and 12 show an example of such a CIS, CIS 100 including a conventional light source. FIG. 11 is a plan view of CIS 100 disclosed by Japanese Patent Laying-Open No. 4-360458 (Japanese Patent No. 2953595), and FIG. 12 is a cross sectional view of CIS 100 shown in FIG. 11.
As shown in FIGS. 11 and 12, CIS 100 includes an LED (Light Emitting Diode) array 101 as a light source, a casing 102, a sensor IC (integrated Circuit) 103, a rod lens array 104, and a glass plate 105.
A document 106 between a platen 107 and glass plate 105 is irradiated with light by LED array 101, and reflected light is passed through rod lens array 104 to reach sensor IC 103. The reflected light is then converted into an electrical signal by sensor IC 103 and the content of document 106 is read.
The use of LED array 101 as a light source for a contact image sensor as described above is encountered with the following various disadvantages.
When an LED is used as a light source, the necessary light amount of the light source changes depending upon the time required by the image sensor to read one line of information in the case of a line sensor. This means that the signal output I of the sensor has the relation represented as Ixe2x88x9dTxc3x97B relative to the reading speed (reading time T per line) and the brightness B of the light source. Therefore, if reading time T is large (a document is read by a facsimile machine for example at the speed of xcx9c10 ms/line), an output from the sensor is tolerable for use.
Note however that reading time T would be very small for high speed reading at a speed of 0.5 ms/line or less, and therefore sufficient sensor output does not result.
When LED chips are arranged, the optical output of the LED chips has strong directivity, the light amount is much different between forward and diagonally forward directions, and therefore the following problem is encountered. When a light source is manufactured using an arrangement of LED chips, a gap is present between LED chips by the restriction of the mounting pitch, which causes difference in the light amount between the region over the LED chips and the region over the gaps. As a result, a corrugation is generated in the amount of light at the LED mounting pitch in the direction of the arrangement of the LED chips.
Furthermore, because of variation in the LED mounting precision (precision at which the light emitting center of the LEDs is aligned on one line) and the directivity of the light amount as described above, the above corrugation could be larger.
In addition, there is variation in the brightness itself of LED chips, and therefore, using an arrangement of LED chips, the brightness variation is reflected upon the brightness distribution on a line. Therefore, the light amount could not be uniform for the entire illumination length.
When a high brightness is to be achieved, LED chips must be mounted in a high density to increase current contributing to light emission, which however causes the light source to generate heat and hence reduces the useful life of the LED chips.
As a light source for a CIS, a conventional, cylindrical lump such as a hot cathode tube (fluorescent lamp) and a cold cathode tube could be used. In this case, a sufficient amount of light as a light source could be obtained.
However, the inner shape of the CIS must have such a form to receive the cylindrical light source, and therefore the cross sectional shape would be large. Since such a lamp has electrodes at both ends, a lower brightness portion as long as several centimeters called xe2x80x9ccathode dark spacexe2x80x9d is necessarily formed. As a result, the percentage of the region having a stable light amount relative to the entire length of the light source is reduced.
The inventor has eagerly studied and come to conceive the use of a light source which emits light by discharge for the light source of the contact image sensor, and succeeded in the development of a light source of this type. FIG. 1 shows an example of a discharging and light emitting device 1 which can be used as the light source.
As shown in FIG. 1, discharging and light emitting device 1 includes a substrate 2, a transparent substrate 3, an inner electrode 4, an outer electrode 5, a metal bus 6, an insulating layer (dielectric layer) 7, a first fluorescent substance 8, a second fluorescent substance 9, a sealing layer 10, and a discharging space 11.
Substrate 2 and transparent substrate 3 are made for example of glass. Transparent substrate 3 is placed upon substrate 2, and has a wall 3a extending toward substrate 2. Wall 3a is connected to substrate 2 through sealing layer 10 and insulating layer 7. Thus, a discharging space 11 is formed between substrate 2 and transparent substrate 3. A discharge gas such as xenon is enclosed in discharging space 11. Note that sealing layer 10 is made of a glass layer formed for example by melting frit.
Inner electrode 4 is formed on substrate 2, and covered with insulating layer 7. Insulating layer 7 is for example made of a glass layer. First fluorescent substance 8 is formed on insulating layer 7, and second fluorescent substance 9 is formed on the surface of transparent substrate 3.
Outer electrode 5 is for example made of ITO (Indium Tin Oxide) or SnO2, and has transmittancy. Outer electrode 5 formed on the outer surface of transparent substrate 3 forms metal bus 6 on the periphery of outer electrode 5.
In order to allow discharging and light emitting device 1 having the above construction to emit, a prescribed voltage (for example, about 1000V) is applied between inner electrode 4 and outer electrode 5. Thus, a discharge gas is electrolytically dissociated to discharge ultraviolet rays, which are then directed upon first and second fluorescent substances 8 and 9 and these substances emit light.
The inventor has confirmed that the brightness of light thus obtained is higher than the conventional case using the LEDs. The brightness distribution is homogeneous, the useful life of discharging and light emitting device 1 is significantly longer than that of the LEDs. The percentage of the effective illumination length is much increased, which makes it easier to reduce the size in the longitudinal direction. Furthermore, since no toxic substance such as mercury is used, the risk of environmental destruction can be avoided.
While discharging and light emitting device 1 shown in FIG. 1 may provide various, more excellent effects than those of the conventional device as described above, the inventor has further advanced his study to come across the following, new problem to be solved for such discharging and light emitting device 1. The problem will be now described.
FIG. 2 shows a discharging path 12a in discharging space 11 when discharging and light emitting device 1 emits light. Note that the arrow in FIG. 2 represents the direction in which light is emitted.
As shown in FIG. 2, since inner electrode 4 and outer electrode 5 are placed opposing each other, discharging path 12a is positioned vertically to the main surface of each of substrates 2 and 3. The length of discharging path 12a is therefore as short as the shortest distance between substrates 2 and 3.
In a light source using gas discharging, the brightness and light emission efficiency typically increase as a function of the length of the discharging path length. As a result, the short discharging path length as described above could lower the brightness and light emission efficiency in discharging and light emitting device 1.
The present invention is directed to a solution to the above described problem. It is one object of the present invention to provide a discharging and light emitting device providing an increased brightness, a more homogeneous distribution of brightness, prolonged useful life, a higher percentage of effective illumination length and improved light emission efficiency and allowing the longitudinal size to be reduced, and the environmental destruction to be avoided.
A discharging and light emitting device according to the present invention includes first and second substrates, first and second fluorescent substances, and first and second electrodes. The second substrate is placed upon the first substrate to form a discharging space into which a discharging gas is enclosed with the first substrate and has transmittancy. The first and second fluorescent substances are provided in the discharging space. The first electrode is provided on the side of the first substrate and the second electrode is provided on the side of the second substrate. The second electrode is provided shifted from the first electrode such that the first and second electrodes do not overlap.
By thus providing the second electrode shifted from the first electrode, the discharging path can be tilted at a prescribed angle relative to the direction vertical to the main surfaces of the first and second substrates. More specifically, the discharging path can be directed slightly diagonally to the main surfaces of the first and second substrates. As a result, the discharging path length (discharging gap) can be larger than the case shown in FIG. 1, and the brightness and light emission efficiency can be improved. Discharging light emission is caused in the direction connecting the first electrode and the second electrode, and therefore a light emitting region is hardly generated immediately under the electrodes, so that all the emitted light can be taken to the outside. This also contributes to the improved light emission efficiency. Furthermore, if discharged light is taken using discharging, the smaller the density of the current passed at the time of discharging, the greater will be the light emission efficiency. As a result, if the first electrode is provided shifted from the second electrode, strong discharging is generated in the direction connecting the first and second electrodes, while discharging is weak in the other region. Thus, there is a current density distribution, a low current density region is formed, and the light emission efficiency in total can be improved.
The first substrate has the first fluorescent substance and the second substrate has the second fluorescent substance. The first fluorescent substance preferably has a larger thickness than the thickness of the second fluorescent substance. Thus, light can be emitted through the second substrate.
The first electrode is provided on a surface on the discharging space side in the first substrate, the second electrode is provided on an outer surface on the opposite side to the discharging space side in the second substrate. The second electrode is at a ground potential.
Since the second electrode which could be in contact with the outside is set at a ground potential, the risk of electric shock by touching the second electrode can be avoided and the safe operation environment can be secured. When the casing of the discharging and light emitting device is set at a ground potential, the casing and the second electrode do not have to be insulated from one another any longer, which prevents the structure from being complicated and enlarged. Furthermore, the shielding effect against an EMI (radiation noise) from the light taking portion can be provided. The driving frequency for emitting light is in the range from 50 KHz to 100 KHz, and the wavelength is larger than the opening of the light source (discharging and light emitting device), so that the shield effect can be expected for this structure as well.
Preferably, the second substrate has a wall (spacer) extending toward the first substrate, and the second electrode is provided on the inner side than the wall of the second substrate.
If a substance having a large dielectric constant is present between the electrodes other than the discharging gas, a capacitor forms between the substance and the electrodes. The capacitor has a larger capacitance than the discharging gas space. When a voltage to cause light emission is externally applied, the number of charges not contributing to the light emission and charging the capacitor is greater than that of charges for raising the voltage for the discharging space, which lowers the efficiency as a whole (the percentage of the light amount relative to input power). Since the dielectric constant of the wall described above is large, and therefore by providing the second electrode on the inner side than the wall, the wall can be prevented from being provided with voltage, and the efficiency can be prevented from being lowered. Thus, wasteful power consumption can be reduced, and the light emission efficiency can be improved.
The first electrode may be provided on an outer surface positioned on the opposite side to the discharging space side in the first substrate, while the second electrode may be provided on a surface on the discharging space side in the second substrate. In this case, the first electrode is set at a ground potential.
An insulating layer covering the second electrode and having transmittancy is preferably provided. Thus, light can be let out through the insulating layer.
The above insulating layer may be provided with an opening to reach the second substrate, and the second fluorescent substance may be formed on the surface of the second substrate positioned in the opening.
When light is emitted to the outside from the insulating layer side, the above opening permits light to be passed through the opening for emission to the outside. Thus, the brightness can be increased as compared to the case of emitting light through the insulating layer to the outside. The transparency of the insulating layer does not have to be improved in this case.
A wall extending toward the second substrate may be formed on the side of the first substrate. In this case, the first electrode is provided on the inner side of the wall of the first substrate. Also in this case, the light emission efficiency can be improved.
The first electrode is formed into a flat plate (strip) shape, and the second electrode is formed into an annular shape. In this case, discharging is caused on both sides of the first electrode, and the brightness and light emission efficiency can be further improved. In addition, discharging light emission is generated in the region surrounded by the annular second electrode, a light emitting region is less likely to be formed immediately under the electrodes, and therefore all the emitted light can be let out. Also in this case, a low current density region can be positively produced, which improves the light emission efficiency in total. If one side of the second electrode being disconnected, it will not be defective and the margin relative to the disconnection of electrodes can be improved. Furthermore, the outlet of light can be clearly defined by the second electrode.
The discharging and light emitting device according to the present invention is particularly useful as a light source for a contact image sensor.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. | {
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1. Field of the Invention
The present invention relates to, for example, conversion apparatus configured to operate between a synchronous communication network and an asynchronous communication network to convert transmission signals from the communication networks in accordance with the protocols of the respective communication networks.
2. Description of the Related Art
In a conventional communication system, a synchronous communication network accommodates a transmission apparatus used for circuit switching and a terminal apparatus configured to transmit and receive signals to and from the transmission apparatus. In such a communication system, a clock is synchronized between the transmission apparatus and the terminal apparatus. The transmission apparatus and the terminal apparatus carry out data communication by transmitting and receiving data in synchronism with the clock.
In recent years, there has been a demand to change the synchronous communication network to an Internet protocol network (IP network) that is an asynchronous communication network. This is because when a communication infrastructure is used as an IP network instead of a synchronous communication network in which only special apparatuses can be connected to the network as terminals, the number of apparatuses that can be connected to the network increases sharply and apparatus costs reduces. Thus, in association with the change from a synchronous communication network to an IP network that is an asynchronous communication network, conversion apparatuses for communication between the existing synchronous communication network and the IP network have been proposed.
A known technique used for such conversion apparatuses is Circuit Emulation Service over Packet Switched Network (CESoPSN). The CESoPSN technique converts a synchronous clock into a special packet, which is then placed among IP packets for transmission. The conversion apparatus receives and converts the IP packets into original data based on the clock in the special packet.
In the IP network, IP packets are transmitted in accordance with a best-effort transmission scheme. Thus, depending on the transmission environment, transmission of the IP packets may be delayed or IP packets may be discard. Here, if the special packet included in the IP packets is discard, clock synchronization cannot be maintained between the synchronous communication network and the IP network. Thus, if an error such as a discard IP packet occurs, an alarm signal (alarm indication signal [AIS]) is provided to the transmission apparatus connected to the conversion apparatus (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 5-244203). Here, by definition, an AIS means that an error is also occurring in the clock for the circuit. Thus, upon receiving the AIS, the transmission apparatus in the synchronous communication network disconnects from the conversion apparatus. The transmission apparatus then switches the synchronization to its own clock for the synchronous communication network. The transmission apparatus waits for the IP network to recover, and upon receiving the notification that the IP network has recovered, synchronizes with the clock of the conversion apparatus. The transmission apparatus then resumes communication via the conversion apparatus in accordance with the clock.
As described above, even if an error in the IP network causes the communication to be cut off to make the clock between the synchronous communication network and the IP network asynchronous, the recovery of the IP network allows the clock to be synchronized to resume communication. Thus, the asynchronous status of the clock often fails to be acknowledged as a problem. However, if the synchronous communication network accommodates a base station configured to control communication between a plurality of radio terminals, data communication is desirably recovered quickly. In this case, after the error in the IP network is eliminated, a long time may disadvantageously be required to recover the clock synchronization between the synchronous communication network and the IP network. | {
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1. Field of the Invention
This invention relates to a display device, especially to a display device with a DA conversion function converting a digital image signal into an analog image signal.
2. Description of the Related Art
An electroluminescent (referred to as EL hereinafter) display device with an EL element has been gathering attention as a display device substituting a CRT or an LCD. The development effort for the EL display device with a thin film transistor (referred to as TFT hereinafter) as a switching element for driving the EL element has been made accordingly.
FIG. 7 is an equivalent circuit diagram of a pixel of an organic EL display panel. A gate signal line 50 supplying a gate signal Gn and a drain signal line 60 supplying a drain signal, a video signal Dm, cross each other. The video signal Dm is produced by sampling a video signal by using a sampling signal.
An organic EL element 120, a TFT 100 for driving the organic El element 120, and a TFT 110 for selecting the pixel are disposed near the crossing of the signal lines.
A positive source voltage PVdd is applied to the drain 100d of the driving TFT 100 of the organic EL element. And the source 100s is connected to an anode 121 of the organic EL element 120.
The gate 110g of the TFT 110 for selecting pixel is provided with the gate signal Gn by being connected to the gate signal line 50, and provided with the video signal Dm by being connected to the drain signal line 60. The source 110s of the TFT 110 is connected to the gate 100g of the TFT 100. The gate signal Gn is generated from a gate driver circuit (not shown in the figure). The video signal Dm is outputted from a drain driver circuit (not shown in the figure).
The organic EL element 120 includes the anode 121, a cathode 122 and an emissive layer 123 inserted between the anode 121 and the cathode 122. The cathode 122 is provided with a negative source voltage CV.
A storage capacitance element 130 is connected to the gate 100g of the TFT 100. That is, one of the electrodes of the storage capacitance element 130 is connected to the gate 100g, and the other electrode is connected to a storage capacitance electrode 131. The storage capacitance element 130 is disposed in order to keep the video signal of the pixel for one field period by keeping the charge corresponding to the video signal Dm.
The operation of the display device with the above configuration is as follows. The TFT 110 turns on when the gate signal Gn becomes a high level for one horizontal period. Then the video signal Dm is supplied from the drain signal line 60 to the gate 100g of the TFT 100 through the TFT 110. The conductance of the TFT 100 changes according to the video signal supplied to the gate 100g and the corresponding driving electric current is supplied to the organic EL element 120 through the TFT 100, which results in an illumination of the organic EL element 120.
An analog image signal inputted to the drain signal line 60 is obtained by converting the inputted digital image signal into the analog image signal by a D/A converter. Conventional display devices with a D/A converter built inside the display panel usually have the D/A converter near the driver circuit disposed in the peripheral area of the pixels.
However, since the D/A converter is disposed near the driver circuit, the conventional display device has complicated circuit designs in the peripheral area of the pixels, leading to an enlarged framing area of the display panel to accommodate the D/A converter. | {
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1. Field of the Invention
The present invention relates to a small lightweight snow flinger and more particularly pertains to remove settled snow from a side walk, drive way or like surface with a small light weight device.
2. Description of the Prior Art
The use of snow removal devices of various designs and configurations is known in the prior art. More specifically, snow removal devices of various designs and configurations heretofore devised and utilized for the purpose of removing snow by various methods and apparatuses are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
By way of example, the prior art discloses in U.S. Pat. No. 3,571,838 to Stasechke discloses a snow removal implement.
U.S. Pat. No. 4,809,386 to Re discloses a combined manual implement for window snow removal, ice scraping, washing and drying, for vehicles in general.
U.S. Pat. No. 4,070,771 to Yakiwchuk discloses a portable snow blower.
U.S. Pat. No. 4,104,812 to Stribiak, Jr., discloses a snow blower for powered lawn mowers.
U.S. Pat. No. 3,643,356 to Gohl discloses a hand-operated snow removing tool.
Lastly, U.S. Pat. No. 5,163,276 to Mohrman discloses multi-purpose attachments for power lawn mower blades.
In this respect, the small lightweight snow flinger according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of remove settled snow from a side walk, drive way or like surface with a small light weight device.
Therefore, it can be appreciated that there exists a continuing need for new and improved small lightweight snow flinger which can be used for remove settled snow from a side walk, drive way or like surface with a small light weight device. In this regard, the present invention substantially fulfills this need. | {
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The histamine receptors, H1, H2 and H3 are well-identified forms. The H1 receptors are those that mediate the response antagonized by conventional antihistamines. H1 receptors are present, for example, in the ileum, the skin, and the bronchial smooth muscle of humans and other mammals. Through H2 receptor-mediated responses, histamine stimulates gastric acid secretion in mammals and the chronotropic effect in isolated mammalian atria.
H3 receptor sites are found on sympathetic nerves, where they modulate sympathetic neurotransmission and attenuate a variety of end organ responses under control of the sympathetic nervous system. Specifically, H3 receptor activation by histamine attenuates nonepinephrine outflow to resistance and capacitance vessels, causing vasodilation.
Imidazole H3 receptor antagonists are well known in the art. More recently, non-imidazole H3 receptor antagonists have been disclosed in PCT US01/32151, filed Oct. 15, 2001, and U.S. application Ser. No. 10/095,134, filed Mar. 11, 2002.
U.S. Pat. No. 5,869,479 discloses compositions for the treatment of the symptoms of allergic rhinitis using a combination of at least one histamine H1 receptor antagonist and at least one histamine H3 receptor antagonist. | {
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1. Field of the Invention
The present invention generally relates to devices and methods for rapidly identifying chemicals with biological activity in liquid samples, particularly automated screening of low volume samples for new medicines, agrochemicals, or cosmetics.
2. Description of the Related Art
Drug discovery is a highly time dependent and critical process in which significant improvements in methodology can dramatically improve the pace at which a useful chemical becomes a validated lead, and ultimately forms the basis for the development of a drug. In many cases the eventual value of a useful drug is set by the timing of its arrival into the market place, and the length of time the drug enjoys as an exclusive treatment for a specific ailment.
A major challenge for pharmaceutical companies is to improve the speed and efficiency of this process while at the same time maintaining costs to an absolute minimum. One solution to this problem has been to develop high throughput screening systems that enable the rapid analysis of many thousands of chemical compounds per 24 hours. To reduce the otherwise prohibitive costs of screening such large numbers of compounds, typically these systems use miniaturized assay systems that dramatically reduce reagent costs, and improve productivity. To efficiently handle large numbers of miniaturized assays it is necessary to implement automatic robotically controlled analysis systems that can provide reliable reagent addition and manipulations. Preferably these systems and the invention herein are capable of interacting in a coordinated fashion with other systems sub-components, such as a central compound store to enable rapid and efficient processing of samples.
Miniaturized high throughput screening systems require robust, reliable and reproducible methods of analysis that are sensitive enough to work with small sample sizes. While there are a large number of potential analysis methods that can successfully be used in macroscopic analysis, many of these procedures are not easily miniaturizable, or lack sufficient sensitivity when miniaturized. This is typically true because absolute signal intensity from a given sample decreases as a function of the size of the sample, whereas background optical or detector noise remains more or less constant for large or small samples. Preferred assays for miniaturized high throughput screening assays have high signal to noise ratios for very small sample sizes.
Fluorescence based measurements have high sensitivity and perform well with small samples, where factors such as inner filtering of excitation and emission light are reduced. Fluorescence based measurements therefore exhibit good signal to noise ratios even with small sample sizes. A particularly preferred method of using fluorescence based signal detection is to generate a fluorescent (emission) signal that simultaneously changes at two or more wavelengths. A ratio can be calculated based on the emission light intensity at the first wavelength divided by the emitted light intensity at a second wavelength. This ratiometric measurement of a fluorescent assay has several important advantages over other non-ratiometric types of analysis. Firstly, the ratio is largely independent of the actual concentration of the fluorescent dye that is emitting fluorescence. Secondly, the ratio is largely independent of the intensity of light with which the fluorescent compound is being excited. Thirdly, the ratio is largely independent of changes in the sensitivity of the detector, provided that is that these changes are the same for the detection efficiency at both wavelengths. This combination of advantages makes fluorescence based ratiometric assays highly attractive for high throughput screening systems, where day to day, and, assay to assay reproducibility are important.
Traditionally, there are two general ways to read fluorescence from a multi-well plate. In one arrangement, a read head is moved from well to well and at each well, there is a dwell time during which the fluorescence signal is digitized and stored into memory. Optically, this scheme is the simplest. There is only one optical assembly, one set of filters and one detector. However, depending on how many wells there are in the plate, the read time can be unacceptably long. It is not just the dwell times that contribute to the total read time. Every time the read head is moved from well to well, it takes time to accelerate and decelerate the stage used in moving the setup.
In the other arrangement, some sort of parallelism is employed. Either a picture is taken of the plate, using a CCD camera or some other imaging arrangement, or multiple optical read heads are employed. The advantage of this arrangement is a significant reduction in the read time. However, a new difficulty is introduced, namely that of normalization. When several wells are read at the same time by several read heads, the question that arises is how to make sure that these heads behave in the same way in terms of collection efficiency, detector sensitivity, filter quality and the like. In the case of a CCD camera, the analogous issue is one of flat-fielding. Accordingly, improved methods and systems for rapidly and accurately measuring fluorescence signals in high throughput screening environments are needed.
A multiwell plate scanner comprises a detector which is scanned continuously over wells of a multiwell plate. The scanner may also be used for scanning microarrays, bio-chips and areas of samples not having physical separations.
In one embodiment, the invention is directed to a method of detecting light emitting molecules in wells of a multiwell plate. The method comprises positioning a light collector to one side of a first well of the multiwell plate continuously moving the light collector relative to the multiwell plate such that the light collector passes a first edge of the first well, passes over the first well, and passes a second edge of the first well. Fluorescent light intensity is measured during at least a portion of the time the light collector is over the first well.
The scanner may be used in a high throughput screening system comprising a storage and retrieval module, a sample distribution module, a reagent distribution module, and a detector which incorporates the scanner. One embodiment of the invention thus comprises a high throughput drug discovery method comprising retrieving chemicals from a chemical storage and retrieval module, placing the chemicals into wells of multi-well plates, scanning the multi-well plates in a substantially continuous raster scan pattern so as to detect a chemical or biological activity of one or more of the chemicals. Alternatively, the scan pattern could be in a spiral, concentric circle, or any other suitable mathematical function, depending on the shape of the sample or sample container.
The present invention is also directed to compositions and therapeutics identified by the disclosed methods. One such embodiment comprises a medicament made by a process comprising identifying a pharmacologically active chemical by a process comprising retrieving chemicals from a chemical storage and retrieval module, placing the chemicals into wells of multi-well plates, and scanning the multi-well plates in a substantially continuous plowman""s fashion so as to detect a pharmacological activity of one or more of the chemicals. Following identification, an effective amount of at least one of the pharmacologically active chemicals is incorporated into a biocompatible carrier.
A further aspect of the present invention is a method of testing a therapeutic for therapeutic activity and toxicology by identifying a compound using a method of the present invention and monitoring the toxicology and efficacy of the therapeutic in an in vivo model. | {
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1. Field of the Art
The disclosure relates generally to semiconductors, and more specifically, to configuring a supply voltage in a semiconductor device.
2. Description of the Related Art
Power management is an important problem in semiconductor devices. In order to reduce power consumption of devices, it is often desirable to operate the devices at the lowest possible supply voltage at which the device will meet desired performance standards. However, because performance is also affected by manufacturing variations between devices, this ideal operating voltage may vary significantly between devices. Furthermore, the ideal operation voltage may vary between different supply voltages on the same device. | {
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The present invention relates to a semiconductor device, a semiconductor system including same, and a semiconductor device control method. The invention relates to a semiconductor device, a semiconductor system including same, and a semiconductor device control method which are suitable for correctly judging that, for example, any module has been coupled to and decoupled from a communication bus.
For data communication between a controller and a module, a communication scheme, I2C (Inter-Integrated Circuit) is widely used. In I2C communication, since a controller and plural modules can be coupled through a shared bus, the number of wiring lines for signal transmission can be decreased.
In I2C communication, after a controller (master) transmits a data write or read command to a module (slave), when the controller has received a reply (ACK signal) to the transmission from the module, it actually performs data write or read.
In this regard, after transmitting a data write or read command to a module, the controller can become aware of failure or decoupling of the module only when it has failed to receive a reply to the transmission from the module properly.
However, in such a framework, for example, let us suppose that the controller gives a command to perform steady operation to a module having a moving part, such as a motor; even if the module has been decoupled from the bus during its operation, the controller would misjudge that the module performs steady operation until giving a different command from the one for steady operation to the module. In consequence, there is a possibility of system malfunction occurring.
A solution to this problem is disclosed in Patent Document 1. A coupling detection device disclosed in Patent Document 1 includes a coupling detector circuit in which potential at point A varies when an external unit has been coupled to a coupling detecting terminal, an AD converter which outputs a digital signal corresponding to the potential at point A, and a coupling detection controller which judges whether or not an external unit is being coupled to the coupling detecting terminal according to a signal output by the AD converter. Thereby, a main unit (controller) equipped with the coupling detection device can judge the coupling/decoupling of an external unit promptly. | {
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The present invention relates to an apparatus for determining a rotation center of a rotary body, and more particularly to an apparatus for determining a rotational angular center of a rotary body rotating in cooperation with steering wheel for an automotive venhicle and the like.
Hitherto, in vehicles including automotive vehicles a rotary disk which rotates in cooperation with the steering wheel is provided. A plurality of slits are provided an equiangular distance in the rotary disk, and two photo-interrupters are disposed closely to the rotary disk to face the slits. A light passing through the slit is detected by the photo-interrupters, thereby information relating to the steering is obtained and used to conduct various controls. Namely, the two photo-interrupters produce pulse like electric signals which are the same in the waveform but nearly 90 degrees out of phase from each other. The electric signals are counted to detect a rotational direction and a rotational angle of the steering wheel.
However, there is no means to correct an error in such a conventional rotational angular detector, in such a case that an erroneous count occurs in the counter due to electric noises etc., resulting in the problem that the system erroneously operates according as the errors are accumulated. Moreover, when there is employed a power cut off method in which the power feed to the rotation angular detector is cut off after the power supply is switched off in order to lessen power consumption, a change of an angular position of the steering wheel until the ignition switch is turned on next time results in an error and such errors are accumulated.
In addition, since the rotational angle detector produces same output value per each 360 degrees rotation of the steering wheel in clockwise and counterclockwise directions, it is impossible to discriminate between the steering angular position when the vehicle advances in a beeline and a steering angular position after the steering wheel has made one revolution, resulting in the possibility that the various controls are erroneously conducted. | {
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1. Field of the Invention
The present invention relates to a monitoring camera, and more particularly to a monitoring camera that is mounted on a wall in a fixed place but can be easily adjusted.
2. Description of Related Art
Monitoring cameras mostly are mounted in a fixed position at a high place in buildings or street corners to provide recordings of a specific location for security purposes or to document accidents. A conventional monitoring camera has a body, a focus ring, a standard lens and an optional telephoto lens detachably mounted on the body, wherein the telephoto lens usually is classed with two international standard, one is a C-mount and the other is a CS-mount.
The focus ring is a disk with a central hole that has an inner flange. The inner flange has an inside surface, a threaded outside surface and a bayonet mount on the inside surface. The threaded outer surface is screwed onto the body.
The telephoto lens or the standard lens is attached to the bayonet mount in the focus ring to hold the lens and to focus of the monitoring camera. Even though the bayonet mount allows the lens to be changed quickly, the bayonet mount is a deficiency in design for a security camera in that the bayonet mount is exposed and inadvertently contact by repair personnel will cause the monitoring camera to lose its precise focus.
Another deficient feature of the design of the conventional monitoring camera is that all switches are attached behind the body so that the monitoring camera is not easily controlled because of limited access space behind the body when the monitoring camera is attached on the wall. Additionally, all switches are exposed without any covering and easily malfunction as a result of dust or moisture.
The present invention has arisen to mitigate or obviate the disadvantages of the conventional monitoring camera. | {
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1. Field of the Invention
The present invention relates generally to optical elements, and more particularly to a non-Lambertian glass diffuser replicated from a master diffuser for use in active lighting applications.
2. Description of the Related Art
Methods for manufacturing and replicating optical components utilizing a master and one or more submasters to achieve a final diffuser product having desired light diffusing characteristics are well known. In many of these methods, the creation of the first generation submaster from the master destroys the master rendering it unavailable for later use. There are also other methods of making a replica of a master which contains optical features identical to that of the master without destroying the master. These other methods are described in one or more pending U.S. applications, referenced below, which are assigned to the assignee of the present invention. However, with each of these methods, the submasters are each made from materials which are not significantly durable or suitable for use under high temperature conditions.
The specific embodiments described below regarding the rubber submaster and the silver and nickel submaster are disclosed in co-pending U.S. application Ser. No. 09/052,586 entitled xe2x80x9cMethod of Making Replicas While Preserving Master,xe2x80x9d commonly assigned to the assignee of the present invention.
One such method involves recording optical features on a photosensitive medium using coherent or incoherent light. The photosensitive medium is then further processed to create a master optical product. A layer of two part silicone epoxy is poured over the master to replicate the optical surface features of the master photosensitive medium in the silicone material. The silicone epoxy layer gets cured at room temperature and becomes rubber. The silicone material is then cured further and separated from the master to obtain a silicone submaster. The soft silicone submaster is then used to make successive generations of submasters or final optical products by covering the soft submaster with a layer of epoxy, covering the layer of epoxy with a plastic substrate, curing the epoxy and separating the epoxy and plastic substrate from the submaster.
Another method of creating a submaster for an optical product involves coating the recorded and developed photosensitive medium master discussed above with a layer of silver instead of silicone. A layer of nickel is electroplated onto the silver layer and then the silver layer and layer of nickel are removed from the photosensitive material or medium to form the submaster. The combined silver and nickel backing form a metal shim submaster which is then used to create final optical products by embossing the surface features of the submaster into epoxies, plastics or polycarbonate materials, or by injection molding such materials into a mold carrying the submaster.
One significant shortcoming with each of these methods is that the final optical products created from the submasters are made from relatively non-durable materials such as plastics, epoxies, or polycarbonate composites. These materials are not suited for use near extremely high temperature light sources and are also not well suited for use outdoors under exposure to cyclical or extreme environmental conditions.
Other commonly assigned U.S. patents and pending applications disclose somewhat related methods for making and recording optical products and replicating those products so that they may be mass produced. For example, U.S. Pat. No. 5,365,354 entitled xe2x80x9cGrin Type Diffuser Based on Volume Holographic Materialxe2x80x9d, U.S. Pat. No. 5,534,386 entitled xe2x80x9cHomogenizer Formed Using Coherent Light and a Holographic Diffuserxe2x80x9d, and U.S. Pat. No. 5,609,939 entitled xe2x80x9cViewing Screen Formed Using Coherent Lightxe2x80x9d, all owned by the present assignee relate to methods for recording and replicating optical products. Each of these U.S. patents is incorporated herein by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
Related U.S. patent applications include Ser. No. 08/595,307 now U.S. Pat. No. 5,956,106 entitled xe2x80x9cLCD With Light Source Destructuring and Shaping Devicexe2x80x9d, Ser. No. 08/601,133 now U.S. Pat. No. 5,838,403 entitled xe2x80x9cLiquid Crystal Display System with Collimated Backlighting and Non-Lambertian Diffusingxe2x80x9d, Ser. No. 08/618,539 now U.S. Pat. No. 5,735,988 entitled xe2x80x9cMethod of Making Liquid Crystal Display Systemxe2x80x9d, Ser. No. 08/800,872 now U.S. Pat. No. 5,922,238 entitled xe2x80x9cMethod of Making Replicas and Compositions for Use Therewithxe2x80x9d, and Ser. No. 09/075,023 now abandoned entitled xe2x80x9cMethod and Apparatus for Making Optical Masters Using Incoherent Light.xe2x80x9d All the above applications are owned by the present assignee and are hereby incorporated by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
A primary object of the present invention is to provide a method for making a replica of a master diffuser containing optical features of the diffuser in an extremely durable material such as glass. It is another object of the invention to provide a diffuser made from a material such as glass which is highly durable and suitable for use under extreme conditions such as adjacent a high temperature active light source such as for liquid crystal displays and the like.
In accordance with the present invention, these objects are achieved by a glass optical element having a unitary body structure made from a glass material and at least one optical surface. A surface relief structure is replicated onto the at least one optical surface from a metal submaster optical element. The glass material is first heated to a suitable temperature in order that the glass be softened to a predetermined level of softness. The softened glass is supported on a sturdy support such as a flat metal surface with at least one surface of the glass substrate exposed. The exposed surface is contacted with the surface relief structure of the metal shim submaster optical element for a length of time while pressure is applied to force the metal submaster optical element and softened glass substrate material against one another during at least a portion of the length of time of contact. By the combination of the softness of the glass, the pressure applied between the master optical element, the glass substrate and the sturdy support surface, and the duration of time of such contact and applied pressure, the surface relief structure is replicated in the glass material. The pressure is then released and the master optical element or metal shim and glass material are separated from one another. The glass is then cooled to produce the glass diffuser according to the invention.
The master optical element may in one embodiment be a metal shim having a silver layer backed by a chromium or nickel layer. The silver layer includes a surface relief structure recorded from a photoresist medium by any one of many conventional means. Other master optical elements may be utilized depending upon the particular glass and process characteristics necessary for production of a desired glass diffuser.
The glass substrate material may also be heated utilizing a number of means. For example, the glass substrate material may be placed within a furnace to elevate the temperature of the glass prior to the application of pressure between the glass material and the master optical element. Alternatively, the glass substrate material may be exposed to a direct heat source such as an oxyacetylene flame in order to sufficiently soften an exposed surface of the glass material. In another alternative, a molten glass material may be slightly cooled to a softened state and then contacted with the master optical element during initial manufacture of a glass substrate thereby replicating the surface relief structure directly into the original glass object.
Using this methodology, the assignee has demonstrated the fabrication of glass diffusers in the laboratory. Different types of metals can be used in place of silver, and or nickel-chromium. One alternative choice of such a metal is steel having a higher percentage of carbon. One can also effectively replicate the glass diffuser using a graphite based diffuser master. For example, a diffuser master structure can be ion milled onto the steel metal and/or graphite materials which have thermal expansion coefficients closer to the glass. The use of graphite is critical when a more softened or liquified glass is used.
These and other aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof and the invention includes all such modifications. | {
"pile_set_name": "USPTO Backgrounds"
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The present embodiments relate to an arrangement having a robot including a robot arm that supports a device powered by supply lines.
One general problem in robots within the industrial and medical technology fields arises if a device supported by a robot arm is powered by a larger number of electrical, hydraulic, pneumatic and/or other supply lines. The supply lines may not be guided within the robot arm since corresponding moveable pins would be used for each supply line in each joint of the robot arm. The supply lines may therefore be guided to the device outside of the robot arm. To protect the supply lines from damage, the supply lines may be guided in a tube. Flexible tubes may be used herefor, since flexible tubes possess high flexibility in all directions in the case of high rigidity.
A line and/or tube provision is provided so that the mobility of the arrangement is not restricted. The line or tube guidance takes place such that the tube and the supply lines running in the tube are not damaged during movement of the robot arm and of the device supported by the robot and that the tube following the movements of the robot arm with an inertia-dependent delay does not cause damage to other components.
An arrangement is known from the patent application DE 10 2007 058 990 A1, whereby the supply lines are guided to the device from above. The supply lines are arranged on a gallows that is rotatably mounted on a rail-guided carriage and are suspended on a longitudinal section using at least one cable pull on the gallows side.
In other words, in accordance with DE 10 2007 058 990 A1, the tube provision is guided as close as possible to the device position by carriages and rotatable gallows. For movements of the device, which is detached using one or several cable pulls since the carriages and gallows of the device are not able to follow, the tube reserve may be available and released if necessary. This relates to device movements in the vertical direction and device movements on the outermost horizontal boundaries of the operating space.
The arrangement according to DE 10 2007 058 990 A1 is problematical in two respects. The design, including rail system, carriage and gallows, is mechanically complicated, and the tube and robot arm may collide. | {
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As one of flat (flat panel) display apparatuses, for example, there is an organic EL display apparatus using, as a light emitting unit (light emitting device), an organic EL device that uses the phenomenon of light emission when applying an electric field to an organic thin film by using electroluminescence (EL) of an organic material.
In the flat display apparatus typified by this organic EL display apparatus, when the characteristics (threshold voltage, mobility, and the like) of a driving transistor that drives the light emitting unit differ for each pixel, the value of current flowing through the driving transistor varies between the pixels. As a result, even when the same voltage is applied to the gate electrode of the driving transistor between the pixels, the light emission luminance of the light emitting unit varies between the pixels, which impairs the uniformity of a screen.
Therefore, each pixel of the flat display apparatus typified by the organic EL display apparatus has a threshold voltage correction function of correcting variations in the characteristics, e.g., variations in a threshold voltage Vth, of the driving transistor driving the light emitting unit in units of pixels (see, for example, Patent Literature 1). | {
"pile_set_name": "USPTO Backgrounds"
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A stent is a medical device introduced to a body lumen and is well known in the art. Typically, a stent is implanted in a blood vessel at the site of a stenosis or aneurysm endoluminally, i.e. by so-called “minimally invasive techniques” in which the stent in a radially reduced configuration, optionally restrained in a radially compressed configuration by a sheath and/or catheter, is delivered by a stent delivery system or “introducer” to the site where it is required. The introducer may enter the body from an access location outside the body, such as through the patient's skin, or by a “cut down” technique in which the entry blood vessel is exposed by minor surgical means.
Stents, grafts, stent-grafts, vena cava filters, expandable frameworks, and similar implantable medical devices are radially expandable endoprostheses which are typically intravascular implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc. They may be self-expanding, expanded by an internal radial force, such as when mounted on a balloon, or a combination of self-expanding and balloon expandable (hybrid expandable).
Depending on the structure and conditions of a body lumen, stents can be prone to stent migration.
One way to reduce the risk of stent migration has been to expose bare metal portions of the stent to lumen tissue. The open, braided structure of the stent may provide a scaffold that promotes tissue ingrowth into the stent. This tissue ingrowth may aid anchoring the stent in place and may reduce the risk of migration. In some cases, however, tissue ingrowth has been known to lead to reocclusion of the body lumen. In addition, stents anchored by tissue ingrowth cannot be moved or removed without an invasive procedure. To reduce tissue ingrowth, stents have been covered with a coating (e.g., made of a polymer, etc.) to create a physical barrier between the lumen and the lumen wall. However, in some circumstance, such stents can have an unacceptable occurrence of migration, as compared to bare metal counterparts.
Another way to reduce the risk of stent migration has been to use a flared stent. However, stents having flares can have an unacceptable occurrence of migration.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the present disclosure a brief summary of some of the claimed embodiments is set forth below. Additional details of the summarized embodiments of the present disclosure and/or additional embodiments of the present disclosure may be found in the Detailed Description below. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates to tuning apparatus and, more particularly, to tuning apparatus which is tunable to desired ones of broadcast frequencies, such as FM and AM broadcast frequencies.
In many geographic locations, and particularly, larger metropolitan areas, a large number of FM and AM radio stations are provided. Thus, a user who has a home entertainment tuning device may receive a multitude of FM and AM broadcast frequencies. Often, the user may prefer to listen to the program entertainment which is transmitted over a relatively small number of such available broadcast frequencies. If a particular program received over one of these broadcast frequencies is not satisfactory, the user may adjust his tuning device so as to receive the program which is transmitted over another preferred broadcast frequency. However, many receivable broadcast frequencies may exist in the frequency band between the two stations to which the user tunes his tuning device. As the tuning condition of this device is changed, the programs which are transmitted via those intermediary broadcast frequencies will be received. Since the tuning condition of the tuning device is changed abruptly during this station-changing operation, the brief reception of undesired broadcast frequency information may be quite annoying and distracting to the user.
In order to rapidly change the tuning condition of a radio receiver from one station to another without accompanying undesired program information which is present in those broadcast frequencies which lie between the two stations, push-button radio tuning apparatus has been proposed. Such push-button tuning devices are used advantageously in automotive radio receivers. However, such push-button tuning devices generally are not provided in high fidelity home entertainment tuning apparatus. It is desirable to provide, in such home entertainment tuning apparatus, presettable means whereby the tuning apparatus can be rapidly and accurately tuned to preset FM and/or AM radio stations. It also is desirable to provide, in such tuning apparatus, the ability to change the preset FM and/or AM stations in accordance with the particular preferences of the user. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates to surgical instruments and, in various embodiments, to surgical stapling and cutting instruments and staple cartridges for use therewith.
A stapling instrument can include a pair of cooperating elongate jaw members, wherein each jaw member can be adapted to be inserted into a patient and positioned relative to tissue that is to be stapled and/or incised. In various embodiments, one of the jaw members can support a staple cartridge with at least two laterally spaced rows of staples contained therein, and the other jaw member can support an anvil with staple-forming pockets aligned with the rows of staples in the staple cartridge. Generally, the stapling instrument can further include a pusher bar and a knife blade which are slidable relative to the jaw members to sequentially eject the staples from the staple cartridge via camming surfaces on the pusher bar and/or camming surfaces on a wedge sled that is pushed by the pusher bar. In at least one embodiment, the camming surfaces can be configured to activate a plurality of staple drivers carried by the cartridge and associated with the staples in order to push the staples against the anvil and form laterally spaced rows of deformed staples in the tissue gripped between the jaw members. In at least one embodiment, the knife blade can trail the camming surfaces and cut the tissue along a line between the staple rows.
The foregoing discussion is intended only to illustrate various aspects of the related art in the field of the invention at the time, and should not be taken as a disavowal of claim scope.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various embodiments of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. | {
"pile_set_name": "USPTO Backgrounds"
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Conventionally internal combustion engines are equipped with exhaust gas aftertreatment systems. One of the functions of the aftertreatment systems in case of Diesel engines is the treatment of NOX emission, considering that it is required by current and future legislation, to reach very stringent emission targets in terms of NOX quantity.
Several aftertreatment systems have been proposed to reach such targets, one of which is an aftertreatment system including a Lean NOX Trap upstream of an SCRF. As known, a Lean NOx Trap (LNT) is a device that is used to reduce nitrogen oxides (NO and NO2) and is a catalytic converter support coated with a special washcoat containing zeolites, while a SCRF is a passive SCR (Selective Catalytic Reduction) catalyst coated on a porous DPF (Diesel Particular Filter). Lean NOX Traps (LNT) are subjected to periodic regenerations to release and reduce the trapped nitrogen oxides (NOX) from the LNT.
In order to perform a regeneration event, also referenced as a DeNOX regeneration, Lean NOX Traps (LNT) are operated cyclically, for example by switching the engine from a lean burn operation to a rich operation. Known LNT control strategies are designed to manage DeNOX regenerations of the LNT as a function of air-to-fuel ratios in the exhaust gas, also known as lambda. In particular, known strategies request a DeNOX regeneration if the LNT NOX conversion efficiency is lower than a predefined threshold thereof, namely if the NOX quantity stored in the LNT is greater than a predefined threshold. Once requested, a DeNOX regeneration is ended when a lambda signal breakthrough is verified, namely at the instant in which an air-to-fuel ratio at an LNT outlet is lower than an air-to-fuel ratio at an LNT inlet.
It is also known that the LNT has the capability of producing ammonia (NH3) during a regeneration event. Ammonia is used by the SCRF downstream of the LNT to improve the total NOX conversion efficiency. | {
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This invention relates to a magnetic pole material for a magnetic head, a composite thin film magnetic head using the same, and a magnetic memory device comprising the composite thin film magnetic head.
In order to realize high-density recording, a magnetic head mounted on a magnetic memory device is required to generate a recording magnetic field more and more increased in magnetic field strength.
In recent magnetic memories such as a magnetic disk unit, a composite thin film magnetic head is predominantly used as a recording/reproducing device. The composite thin film magnetic head comprises a magnetoresistive head and an inductive head as a reproducing head and a recording head, respectively. By individually optimizing the reproducing head and the recording head, the magnetic memory device can further be improved in performance.
In order to increase the magnetic field strength of the recording magnetic field, it is necessary to use a magnetic pole material having a high saturation flux density as a magnetic pole layer of the inductance head. Furthermore, it is essential that the magnetic pole material is easily magnetized under a magnetic field generated by a coil. Therefore, the magnetic pole material must be a magnetic material small in coercive force and high in permeability, i.e., an excellent soft magnetic material.
As the magnetic pole material of the inductive head, use has widely been made of a Nixe2x80x94Fe alloy (permalloy) produced by electroplating.
In the above-mentioned composite thin film magnetic head, use is often made of a permalloy which has a composition range such that the content of Ni is on the order of 81-82 wt % and which has a magnetostrictive constant approximately equal to zero. The permalloy having the above-mentioned composition range will hereinafter be referred to as a 82 permalloy. The 82 permalloy has a saturation flux density between 9000 and 10000 G (gauss). If an excellent soft magnetic material having a higher saturation flux density is used, it is possible to produce a magnetic head having a recording magnetic field great in magnetic field strength and steep in magnetic field gradient.
To this end, proposal has been made of various materials as a soft magnetic material which is for use in a magnetic head and which has a saturation flux density higher than that of the 82 permalloy. In particular, a Coxe2x80x94Fexe2x80x94Ni magnetic film made of a Coxe2x80x94Fexe2x80x94Ni ternary alloy is small in coercive force and magnetostrictive constant and has a high saturation flux density not smaller than 14000G. Therefore, extensive consideration has been made of the composition of the Coxe2x80x94Fexe2x80x94Ni alloy and an additive thereto.
For example, Japanese Unexamined Patent Publication (JP-A) No. H05-263170 discloses a thin film magnetic head using a Coxe2x80x94Fexe2x80x94Ni film containing 60-90 wt % Co, 3-9 wt % Fe, and 5-15 wt % Ni.
Japanese Unexamined Patent Publication (JP-A) No. H08-241503 discloses a thin film magnetic head using a Coxe2x80x94Fexe2x80x94Ni film containing 60-80 wt % Co, 8-25 wt % Fe, and 15-25 wt % Ni.
Japanese Unexamined Patent Publication (JP-A) No. H08-321010 discloses a thin film magnetic head using a Coxe2x80x94Fexe2x80x94Ni film containing 60-75 wt % Co, 3-9 wt % Fe, and 17-25 wt % Ni.
However, each of the above-mentioned Coxe2x80x94Fexe2x80x94Ni films produced by conventional methods has a saturation flux density on the order between 14000 and 18000 G and does not achieve a saturation flux density of a yet higher level. In addition, because of inclusion of such a large content of Co, each of the Coxe2x80x94Fexe2x80x94Ni films is inferior in corrosion resistance than a permalloy film. The corrosion resistance is required to assure the reliability of a device such as a magnetic head in which the Coxe2x80x94Fexe2x80x94Ni film is used.
Japanese Unexamined Patent Publication (JP-A) No. H11-74122 discloses a Coxe2x80x94Fexe2x80x94Ni film containing 40-70 wt % Co, 20-40 wt % Fe, and 10-20 wt % Ni and a method of producing the same. The Coxe2x80x94Fexe2x80x94Ni film disclosed in this publication has a high saturation flux density on the order between 19000 and 22000 G and a low coercive force not greater than 2.5 Oe.
However, the increase in magnetic recording density requires a magnetic head having a higher recording ability. Following the recent progress in increase of the magnetic recording density, a minimum magnetic reversal area as a recording unit becomes so small and is therefore susceptible to the influence of thermal energy even at the room temperature. At a recording density exceeding 10 gigabit/in2, recording magnetization becomes unstable due to thermal fluctuation.
In order to minimize the thermal fluctuation, it is most effective to enhance anisotropy energy of a magnetic layer of a magnetic recording medium so as to stabilize the recording magnetization against the thermal fluctuation. However, such enhancement of the anisotropy energy is equivalent to an increase in strength of a magnetic field required to reverse the magnetization, i.e., an increase in coercive force of the magnetic recording medium. In order to write data into the magnetic recording medium having a large coercive force, it is necessary to increase the strength of a recording magnetic field of the magnetic head. Therefore, a magnetic material having a high saturation flux density and capable of generating a stronger recording magnetic field is required to meet further increase in magnetic recording density.
It is an object of this invention to provide a soft magnetic film small in coercive force and magnetostrictive constant and having a high saturation flux density on the order between 20000 and 23000 G.
It is a specific object of this invention to provide a magnetic material having a less Ni content to achieve a greater saturation flux density with a coercive force and a magnetostrictive constant kept sufficiently small.
It is another object of this invention to provide a magnetic head comprising the above-mentioned magnetic film.
It is still another object of this invention to provide a magnetic memory device capable of suppressing thermal fluctuation even at a high recording density by combining the above-mentioned magnetic head and a recording medium having a large coercive force.
According to this invention, there is provided a CoxFeyNiz magnetic film having a composition represented by a chemical formula of CoxFeyNiz (50xe2x89xa6xxe2x89xa680, 20xe2x89xa6yxe2x89xa640, and 3xe2x89xa6z less than 10 (wt %)) and having an average grain size not greater than 40 nm.
The above-mentioned magnetic film contains a large amount of Co. However, it is possible to improve an corrosion resistance of the film if the content of S (sulfur) as an impurity contained in the film is not greater than 0.1 wt %.
According to this invention, there is also provided a composite thin film magnetic head comprising a reproducing head and an inductive head. The inductive head has a magnetic pole layer a whole or a part of which comprises the above-mentioned Coxe2x80x94Fexe2x80x94Ni magnetic film. In this case, the Coxe2x80x94Fexe2x80x94Ni magnetic film preferably has a thickness between 0.3 and 2.0 xcexcm (both inclusive).
According to this invention, there is also provided a magnetic memory device comprising a combination of the above-mentioned composite thin film magnetic head and a magnetic recording medium. In this case, the magnetic recording medium preferably has a coercive force not smaller than 3500 Oe. If the magnetic recording medium has a greater coercive force not smaller than 5000 Oe and a yet greater coercive force not smaller than 7000 Oe, the magnetic memory device is less susceptible to the influence of thermal fluctuation even upon high-density recording. | {
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Conventional valves, such as those for precision pneumatic driving units and controlled pressure gas delivery systems, often utilize an actuating member made of a shape memory alloy (or SMA), e.g., nickel-titanium alloys. These alloys typically undergo a thermoelastic phase transition during passage from the martensitic to the austenitic phase, and vice versa, such transition being induced by a selected variation in temperature. Below the transition temperature (or martensitic phase), the alloy typically undergoes plastic deformation. The alloy remains in this condition until it is heated to a temperature above the transition temperature (or austenitic phase), at which time it reversibly recovers its original shape. In a typical valve configuration, a shape memory alloy member acts on a valve shutter against the bias of an elastic member, preferably made of steel. Such action on the shutter usually prevails when the temperature of the alloy member is lower than the transition temperature, whereas when its temperature becomes higher than the phase transition temperature, the shutter is overcome by the bias of the alloy member.
This configuration was used mainly to design on-off type valves: see for example U.S. Pat. Nos. 4,570,851, 5,261,597, 5,984,195, wherein the temperature of the shape memory alloy member is directly controlled by the flowing fluid which thus controls the opening and closure of the valve. In U.S. Pat. Nos. 4,736,587 and 4,973,024 the temperature of the shape memory alloy member is controlled by Joule effect by circulation of an electric current through it. In these examples the shape memory alloy member is in the shape of a wire or a coil spring.
Proportionally operating valves with an actuator made of a shape memory alloy heated by Joule effect have also been made. U.S. Pat. No. 5,865,419 discloses a valve shutter which is pulled towards the valve seat by a shape memory alloy wire against the bias of a steel spring. The passage of a controlled electric current through the shape memory alloy wire controls the force exerted on the shutter and therefore the flow section of the valve. The control unit includes a PWM controller to vary the duty cycle of the electric current to be supplied to the wire, thus controlling the amount of heat produced by Joule effect in the wire and therefore the variation of the valve opening following to a variation of the linear deformation of the wire.
U.S. Pat. No. 5,211,371 discloses a valve wherein the shutter actuator is constituted by a shape memory alloy wire arranged coaxially to a counteracting steel coil spring. The valve opening varies with the variation of the current circulating through the wire and provision is made for a control circuit based on the application of an electric drive to the SMA member to circulate a current through it capable to heat it and to operate the actuator. The drive is performed by means of a variable frequency pulse generator as a function of a control voltage applying pulses of the same duration with variable frequency. By increasing the frequency of the pulses the power applied to the SMA member, and then the amount of heating, is increased and vice versa. The control circuit can be associated to a closed loop feedback system.
A similar valve configuration with shape memory alloy actuator and relevant electric power control circuit is disclosed in GB 2251963. The control circuit uses a PID controller and is based, inter alia, on the variation of the resistivity of the SMA member as a function of the phase transitions of the constituent material.
While useful, valves with shape memory alloy actuators are limited in the attainable degree of controlled precision in response time that can be achieved. Response time must, of course, be as short as possible, especially when the SMA member is returned to the austenitic phase. | {
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This invention relates to a substrate having at least one fine-wired conductive layer, which is suitable for mounting large-scale integrated (LSI) circuits used in data processing and communication systems.
In a wired substrate mounted with LSI circuits for use in high speed computers implemented with highly dense designing, gold and copper can be used as wiring conductive layers to keep the electric resistances of said conductive layers sufficiently low. Further, polyimide resin having a high insulating capacity and a low dielectric rate can be used as an insulator between the wiring conductive layers of a multi-layered substrate. However, an inadequate adhesion of the polyimide resin insulating layers and the conductive layers consisting of gold or copper, tend to cause their exfoliation from one another with the result that the performance and reliability of the substrate circuit are substantially deteriorated. To obviate these disadvantages, a paper entitled "High Reliability Metallurgical Structure for Multilevel Substrate Wiring" by W. B. Archey et al published in IBM Technical Disclosure Bulletin, Vol. 24, No. 12, May 1982, p. 6370 proposes a wired substrate having a polyimide resin layer in which chrome films are formed over the surfaces of a copper conductive layer as shown in the drawing. However, the chrome films are adversely affected when exposed to an external environment in the process of forming the wiring conductor and the polyimide resin film. | {
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The invention relates to a novel use of water-soluble polyvinyl alcohol (co)polymers, to an electrodeposition bath comprising polyvinyl alcohol (co)polymers, and to coated substrates produced using same.
Electrodeposition coating is a well-known method of coating the surface of electrically conducting articles (compare, for example, Glasurit Handbuch Lacke und Farben, Curt R. Vincentz Verlag, Hanover, 1984, pages 374 to 384 and pages 457 to 462, and also DE-A-35 18 732, DE-A-35 18 770, EP-A-0 040 090, EP-A-0 012 463, EP-A-0 259 181, EP-A-0 433 783 and EP-A-0 262 069). The method is used to coat objects made of metal, especially for the priming of automobile bodies, or else to coat conductive plastics.
The coating materials used in electrodeposition coating generally comprise amino or carboxyl-containing synthetic resin binders, with dispersibility in water being achieved by neutralization of the amino or carboxyl groups. The electrodeposition coating materials may further include special grinding resins and possibly further constituents not dispersible in water, such as polymers, plasticizers, pigments, fillers, additives, and auxiliaries. The crosslinking agents used in the electrodeposition coating materials either are not dispersible in water or may be water-dispersible, with the electrodeposition coating materials being externally crosslinking or else self-crosslinking, or being curable with condensation.
Modification to the binders, selection of the crosslinkers, and variation of the composition of the ingredients of the electrodeposition coating material influence the properties of the coating, such as corrosion protection, adhesion, and leveling, for example. For instance, there have been disclosures in particular of electrodeposition coating materials where by adding polymer microparticles or suspended and/or dispersed polymer powders the intention is to exert a favorable influence on corrosion protection, especially at edges, [lacuna] on leveling.
For instance, EP-A-0 259 181 recommends remedying the increased susceptibility to corrosion which is observed at edges of the coated substrate and is caused by a paint film of insufficient thickness by adding polymer microgels, possible ingredients of such microgels being, for example, poly(meth)acrylate copolymers in combination with ethylenically unsaturated vinyl compounds.
Microgel dispersions which are based on epoxy-amine adducts and can be added subsequently are notable for their high compatibility and efficacy as edge protection additives, as described in EP 0 626 000.
DE-B-26 50 611, EP-A-0 052 831, DE-A-39 40 782, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410 and JP-A-0624820 describe electrodeposition coating compositions with suspendable or dispersible polymer powders which are predominantly free from ionic groups, are able to melt on baking if desired, and are uncrosslinked or crosslinked, said coating compositions further comprising the water-dispersible synthetic resins that are typical of electrodeposition coatings. The particle sizes of such polymer powders may considerably exceed the particle sizes of the water-dispersible synthetic resins of known electrodeposition coating materials: the average particle diameter in JP-A-0624820 is from 1 to 50 micrometers and in DE-A-39 40 782 or EP-A-0 433 783 is from 0.1 to 100 micrometers.
In many cases, the addition of the polymer particles described in EP-A-0 259 181, DE-B-26 50 611, EP-A-0 052 831, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410 and JP-A-0624820 to aqueous electrodeposition coating materials leads to an improvement in edge coverage. On the other hand, despite the improved edge coverage, the corrosion protection afforded by the deposited electrodeposition coating films, especially at the edges, is inadequate.
Disadvantageous side effects of adding polymer powders include a deterioration in the throwing power of the electrodeposition coating materials and in adhesion to the substrate and/or to subsequent coatings, such as paint films applied subsequently or PVC underbody protection, impairment of the mechanical properties, such as flexibility, stretchability, fracture strength and impact strength, poorer flow properties, and a drastic deterioration in leveling.
A furthermore [sic] key disadvantage of the aqueous and nonaqueous formulations described in the patents EP-A-0 259 181, DE-B-26 50 611, EP-A-0 052 831, EP-A-0 433 783, SU-A-436890, JP-A-53094346, JP-A-79028410, JP-A-0624820, SU-A-661637, SU-A-998592 and SU-A-310952 is the inadequate stability of the coating materials, which tend toward sedimentation. In aqueous electrodeposition coating materials, this may result in massive coverage of the ultrafiltration membrane with coarse polymer particles.
The stability disadvantages of the coating materials are alleviated by incorporating copolymers having vinyl acetal, vinyl alcohol and ethylene units directly into the resins, and/or by grafting reaction, as described in DE 196 18 379.
In this case a fraction of more than 10% by weight of polymer resin is needed in order to achieve sufficient edge coverage.
The incorporation of polymer powder or microgels requires fractions in the percent range, with a deterioration—in some instances drastic—in leveling.
Significantly more effective, even at low concentrations such as 500 ppm, in the electrodeposition coating material are water-soluble cellulose ethers, such as hydroxyethylcellulose (EP 0 640 700). The activity does not last, since the polymer degrades.
Polyvinyl alcohols are used multifariously in coating materials, in particular as suspension stabilizers for the polymerization of vinyl monomers. Whereas the use of polyvinyl alcohols as complexing agents and suspension stabilizers in the pretreatment of iron, steel, zinc and aluminum sheets, in combination with chromates and/or fluorine compounds, is known (J 73008702, WO 9627034), especially the electrophoretic deposition of metal suspensions, such as aluminum (SU 738334, J-A-111201), metal oxide suspensions, such as of chromium, aluminum, titanium and zirconium oxides (J-A-111201, SU 493817), metal salt suspensions, such as of lead, zinc or copper salts (SU 436890, SU 511392, SU 054452, WO 9208168), and also direct deposition of metals, such as lead (SU 321265), the direct use in electrodeposition coating materials is restricted to subsequent treatment of the deposited film by contact with an aqueous polyvinyl alcohol solution followed by baking. This subsequent treatment achieves a flatting effect (JP 56044799) or reduces surface defects, such as craters (DE 4303787). | {
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A progressive power lens has a part in which a power is progressively changed, and fields of view for viewing different distances (for example, a distance portion for distance vision, a near portion for near vision or the like) can be obtained by a single lens, and therefore the progressive power lens is mainly used as a glasses lens for correction for presbyopia.
Various progressive power lenses having various surface configurations are known, and one of them is a progressive power lens having a so-called both-sides composite progressive structure (for example, see Patent Literature 1). In the progressive power lens having the both-sides composite progressive structure, a power, which is progressively changed, is divided into a power change in a vertical direction of the lens (namely, an up and down direction in use of the lens) and a power change in a horizontal direction of the lens (namely, a left and right direction in use of the lens), and sharing rates in respective directions suitable for two surfaces of a front and a rear surfaces are defined, and thereby one progressive power lens is formed. Specifically, for example, a surface configuration in which the power change in the vertical direction of the lens having a progressive refractive power function is given to only an object side surface (namely, a convex surface), and the power change in the horizontal direction of the lens is given to only an eyeball side surface (namely, a concave surface) is adopted. In such a surface configuration, the front and the rear surfaces of the lens are formed in aspherical surfaces without having a progressive surface, respectively.
Accordingly, the progressive power lens having the both-sides composite progressive structure is structurally different from any of “an outer surface progressive power lens” in which a progressive surface is arranged on an object side surface, “an inner surface progressive power lens” in which the progressive surface is arranged on an eyeball side surface, and “a both-sides progressive power lens” in which the progressive surfaces are used for the front and the rear surfaces and a desired addition power is shared by the front and the rear surfaces. According to the progressive power lens having the both-sides composite progressive structure having such a surface configuration, both of an advantage of “the outer surface progressive power lens” in which a swing angle of an eyeball when a line of sight is moved between respective fields of view corresponding to different distances can be less, and an advantage of “the inner surface progressive power lens” in which a jumping and warping of images can be reduced by suppressing magnification difference between respective fields of view corresponding to the different distances can be obtained.
Here, in a glasses lens including a progressive power lens having a both-sides composite progressive structure, it is known as general technical common knowledge that to form a meniscus shape such that an object side surface is formed by a convex surface and an eyeball side surface is formed by a concave surface (for example, see paragraph [0031] in Patent Literature 1). | {
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Gable roofs are one of the most common roof types. With a gable roof, there can be a gable overhang where the roof extends beyond the wall. In general, gable overhangs are twelve to 24 inches wide, but can be narrower or wider. As shown in FIGS. 1a and 1b, the gable overhang end 10 of the roof consists of a gable end rafter 12, ladder framing boards 14 and a fascia rafter 16.
The gable end rafter 12 is generally supplied as a pre-assembled component and is placed so that it is aligned with the outside wall of the structure. Ladder framing boards 14 are then connected to and/or supported by the top board 18 of the gable end rafter 12 in one of two common ways. The first way, as shown in FIG. 1a, is to drop the gable end rafter 12 so that it sits lower than the second rafter 15 by the width of the ladder framing boards 14 and lay the ladder framing boards 14 across the top board 18 of the gable end rafter 12. The second way, as shown in FIG. 1b, is to notch the top board 18 wherever a ladder framing board 14 will intersect the top board 18 and then insert the ladder framing board 14 within the notch.
The first ends 17 of the ladder framing boards 14 are then attached to the second rafter 15. The length of the ladder framing boards 14 is determined by the width of the overhang and extend this distance beyond the wall. Once the ladder framing boards 14 are in place and attached to the second rafter 15 and the top board 18, the fascia 16 is attached to the second ends 19 of the ladder framing boards 14.
The problem is that it is time consuming to construct the gable overhang, assembly must be performed on site and on the roof, and attachment of the fascia board can result in unsafe conditions for the workers. In addition, if not properly constructed, the overhang can weaken resulting in drooping of the overhang. There is a need for a system that is strong, efficient and simple. | {
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1. Field of the Invention
The present invention relates to an apparatus for displaying a video image and, more particularly, to a head-mounted image display apparatus (head-mounted display), a hand-held image display apparatus (hand-held display), and an image projecting apparatus.
2. Description of the Related Art
There have conventionally been proposed head-mounted image display apparatuses (head-mounted displays) and hand-held image display apparatuses (hand-held displays) which guide image light to the pupils of an observer and displays a virtual image. Japanese Patent Laid-Open No. 11-95144 proposes an image display apparatus for displaying an image based on a light beam reflected by a reflection surface that makes a reciprocating rotation.
The image display apparatus described in Japanese Patent Laid-Open No. 11-95144 includes one horizontal scanning unit (shared by left and right eyes) and two vertical scanning units. The horizontal scanning unit and the vertical scanning units scan, via a collimator lens, light beams from two left- and right-eye light sources. An optical system then guides the light to a user's eyes.
An image display apparatus described in Japanese Patent Laid-Open No. 2006-162780 uses a two-dimensional scan mirror, with the goal of optically reducing the apparatus size.
However, neither patent reference includes a detailed description of light source control. Japanese Patent Laid-Open No. 2004-517350 describes an image display apparatus which scans a plurality of light beams simultaneously and arranges images in tiling display.
Japanese Patent Laid-Open No. 2006-220745 presents a problem in a micromirror scanner using the resonance phenomenon of a silicon substrate. Young's modulus of a silicon substrate changes as temperature changes, and the resonance characteristic (maximum resonance frequency) also changes accordingly. At a constant oscillation frequency (when an applied AC voltage has a predetermined frequency), the oscillation angle of a micromirror varies as the temperature changes. For example, even when the temperature of the micromirror changes, the oscillation frequency does not change as long as the frequency of the applied AC voltage is constant. However, as the temperature of the micromirror rises, the oscillation angle of the micromirror decreases. The variations in the oscillation angle of the micromirror cause variations in the scan range of the reflected light of a laser beam emitted toward the micromirror. If there are periods when both the left- and right-eye laser beams irradiate the micromirror and periods when neither the left- nor right-eye laser beam irradiates it, the temperature of the micromirror scanner varies over time. The temperature unevenness appears as image distortion.
In the reciprocating scanning application method for a tiling display described in PCT(WO) 2004-517350, the scanning slope of the left video image and that of the right video image are different. The scan positions in the overlap portion of the left and right video images also shift almost by half of a line. This causes a scan shift at the overlap portion of the left and right video images and consequently makes the joint noticeable. Additionally, since scanning of the right video image is done in a direction opposite to the normal raster scanning direction, each light source requires a buffer. | {
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A useful therapeutic method for the treatment of malignancies is the administration of compounds that stimulate the differentiation of malignant cells to normal cells, thereby inhibiting and/or reversing the malignant transformation. Thus, it has been shown by Suda et al. (U.S. Pat. No. 4,391,802) that 1.alpha.-hydroxyvitamin D compounds (e.g. specifically 1.alpha.,25-dihydroxyvitamin D.sub.3 and 1.alpha.-hydroxyvitamin D.sub.3) possess, for example, potent antileukemic activity by virtue of inducing the differentiation of malignant cells (specifically leukemia cells) to non-malignant macrophages (monocytes). Hence, these compounds are useful for the treatment of certain malignancies, specifically for the treatment of leukemia (Suda et al., U.S. Pat. No. 4,391,802). When used for such treatment, however, these known 1.alpha.-hydroxyvitamin D compounds have the disadvantage that they are also very potent calcemic agents, i.e. they cause elevated blood calcium levels by stimulating intestinal calcium absorption and bone calcium resorption. This calcemic activity represents, indeed, the well-known, classical function of these compounds. Furthermore, the cell differentiation activity (and, hence, antileukemic activity) of these compounds correlates with their calcemic activity. For example, 1,25-dihydroxyvitamim D.sub.3, the most potent compound in inducing the differentiation of malignant cells to macrophages, is also the most potent vitamin D metabolite in stimulating calcium transport or raising serum calcium levels. For practical use as cell-differentiating agents, this potent calcemic activity is, of course, an undesired side effect, since the doses required for efficacy in differentiating malignant cells can lead to excessively high and non-physiological serum calcium levels in the treated subjects. | {
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As integrated circuits (ICs) have continued to become faster, smaller, and more complex, the ability to test them has become more difficult but, at the same time, such testing has become more critical. Integrated circuit designers and manufacturers have come to realize that in order to assure the integrity of their products, high-quality, and cost effective testing must be implemented.
In the past, “bed-of-nails” testers were appropriate where the board-under-test was available to be lowered onto a set of test points (nails) that probe points of interest on the board. These could be sensed (observed) and driven (controlled) to test the complete board. The increasing complexity of boards and the movement to technologies such as nanometer designs, multi-chip modules (MCMs), and surface mount technologies (SMTs) made the bed-of-nails approach ineffective as fewer and fewer nodes on a chip could be externally accessed.
Nevertheless, the concepts of observability and controllability continue to be fundamental in being able to properly test a circuit. In an optimum situation, a circuit can be fully observed and fully controlled. In actual application, both observability and controllability are often limited, sometimes severely, especially in highly integrated circuits.
Scan techniques offer the ability to better observe and control these more complex chips. For example, boundary scan techniques offer the ability to test boundary circuitry of an IC, e.g., circuitry within the IC that directly interfaces with a printed circuit board. Also, internal scan techniques are used to test the circuitry that can be deep within the IC. Each of these techniques will be briefly described to provide context to the present invention.
As is the case in many situations, the adoption of a standard facilitated an industry implementation. In the case of boundary scan, system designers agreed on a unified scan-based methodology that are set forth in IEEE STD 1149.1, 0.4, and 0.6, which are incorporated herein for all purposes. Boundary scan was originally developed by the Joint Test Access Group and is often called JTAG.
The basic architecture of IEEE STD 1149.1 boundary scan is incorporated at the integrated circuit level as shown in FIG. 1. The I/O pins 102 of each IC on the board are connected serially in a standardized scan chain 104 accessed through the Test Access Port (TAP) 106 so that every pin 102 can be observed and controlled remotely through scan chain 104. At the board level, IC 108 can be connected in series with other ICs to form a scan chain 104 spanning the entire board containing multiple ICs. Connections to IC 108 are tested by scanning values into the outputs of each IC 108 and checking that those values are received at the inputs of the IC 108. IC 108 with internal scan chain 104 and BISTs can access those features through the boundary scan technique to provide a unified testing framework.
A key feature of the IEEE STD 1149 boundary scan technique is the implementation of a Test Access Port (TAP) 106. TAP 106 includes four, or optionally five or more, single bit connections. These connections interface with certain on-chip boundary scan logic to implement a communication protocol. The communication protocol used for boundary scan is driven by TCK 120 and TMS 122 and, optionally, TRST 130. TCK 120 is a Test Clock input that is used to, among other things, shift data into and out of ICs 108. TMS 122 is a Test Mode Select input that controls the types of test operations to be conducted. TDI 124 is a Test Data In that inputs the test data and instructions to be used by the IC 108 during testing. TDO 126 is a Test Data Out output that includes the results of the testing. This output is driven only when TAP controller 128 is in the shift TAP controller state, Shift-DR or Shift-IR. Optional TRST 130 is a Test Reset Signal input that is an active low signal that asynchronously resets the TAP controller 108 if no power-up reset signal is automatically generated by IC 108.
When the IC 108 is in a normal mode, TRST 130 and TCK 120 are held low and TMS 122 is held high in order to disable boundary scan. To prevent race conditions, inputs are sampled on the rising edge of TCK 120 and outputs toggle on the falling edge.
TAP controller 128 is typically a 16-state FSM that proceeds from state to state based on TCK 120 and TMS 122 signals. It provides signals that control a test data register and an instruction register. These include serial shift clocks and update clocks.
A state transition diagram 200 for the TAP controller 129 is shown in FIG. 2. The TAP controller 128 is initialized to Test-Logic-Reset 202 on power-up by TRST or by an internal power-up detection circuit. TAP controller 128 moves from one state to the next on the rising edge of TCK 120 based on the value of TMS 122. A typical test sequence will involve clocking TCK 120 and setting TRST 130 to 0 for a few cycles and then returning this signal to 1 to reset the TAP controller 108. TMS 130 is then toggled to traverse the state machine for whatever operation is required.
The transition diagram 200, as shown in FIG. 2, provides the roadmap for IEEE STD 1149.1 applications. Each state contains a label with a designated path that depends on the state of TMS 130 at the rising edge of TCK 120. The two vertical columns 204 and 206 each containing seven states that are substantially similar. Column 204 is the data column that makes use of a data register and column 206 is the instruction column that makes use of an instruction register. By traversing the states of column 204, data can be manipulated in IEEE STD 1149.1 testing, and by traversing the states of column 206, instructions can be called out for execution. Operations can include, for example, serially loading an instruction register or serially loading or reading data registers that are used to test interconnections between chips on a board.
More generally, scan techniques can be implemented to test almost any internal circuitry within an IC. To do this, storage elements within an IC are replaced with scan cells. For example, as shown in FIG. 3, where an IC may have multiple storage elements such as D flip-flop storage element 302, such storage elements can be replaced with scan cells 350.
Storage element 302 is shown with inputs D 304, Q 306, and CK 308. In a typical application, the signal at D 304 is output to Q 306 upon the rising edge of clock signal CK 308. Storage elements 302-1, 302-2, and 302-3 can be found throughout an integrated circuit as shown in FIG. 3 to facilitate the operation of combinational logic 310.
Scan cell 350 is more complex than storage element 302 with the addition of multiplexer 352 but operates similarly to storage element 302 during normal operation. In normal operation of scan cell 350 when scan enable SE 354 is set low, the signal at DI 356 is directed to input D 358 and output to Q/SO 360 upon the rising edge of clock signal CK 362. In this way, the implementation of scan cells 350-1, 350-2, and 350-3 with scan enable SE 372 set low allows for the operation of combinational logic 366 to be substantially similar to the operation of combinational logic 310.
Scan cell 350, however, allows for the scanning in and scanning out of data. For example, during a scan-in operation when scan enable SE 354 is set high, scan-in data SI 364 is directed to input D 358 and output to Q/SO 360 upon the rising edge of clock signal CK 362. In this way, test data can be scanned into the internal circuitry of an IC.
The combinational logic 366 of the IC can then operate using such test data and the result can be stored in the same scan cells 350. For example, scan cells 350-1, 350-2, and 350-3 can be configured as a scan chain 368 where data is scanned in through SI 370 by shifting data from scan cell 350-1 to scan cell 350-2 and then to scan cell 350-3 using clock signal 374 when scan enable SE 372 is set high, which is known as Scan Shift Cycle. When all the test data is scanned in, scan enable SE 372 is set low and a test operation can be launched to operate combinational logic 366 under the desired test input. Upon completion of the test, results are stored in scan cells 350-1, 350-2, and 350-3 by applying a clock signal 374 when scan enable SE 372 is set low, which is known as Scan Capture Cycle. The test data can then be scanned out to scan out SO 376 through the use of clock CK 374 when scan enable SE 372 is set high.
With this fundamental understanding of scan testing, the problems associated with such testing can be better understood. As described above, one clock signal is used to drive the test circuitry. The frequency of this capture clock signal is fixed such that for any given test set for the given IC, only one set of test clock frequencies can be used.
With this limitation, a designer that is required to test a complex integrated circuit with many features is limited to one clock frequency for testing the entire circuit. In general, shift operations are performed at a slow speed in order to reduce excessive simultaneous switching noise that can cause shift operations to fail. More precisely, during the Capture Cycle, depending on the delays in the combinational logic 366, different clock frequencies can be used to capture signals at the functional speed. Test and scan pattern generation tools known as ATPG (Automation Test Pattern Generation) have a limitation to use more than one clock frequency for the given test set for the circuit under test (CUT). If a different clock speed is required, another test set for the CUT has to be created such that each clock speed requires its own test set for the CUT. These discrepancies limit the quality of test; add cost and complexity to the test, and provide non-ideal conditions for modern devices.
Where a clock frequency is low, certain circuitry within the IC may not be appropriately exercised. But in using a higher clock frequency, certain circuitry may be appropriately tested but certain other circuitry may be unnecessarily over tested. It may be the case that for this certain other circuitry, real-world applications would never similarly exercise the circuits in terms of speed. The result may, therefore, be that a designer is forced to use a clock frequency that assures proper operation of the whole circuit but that may unnecessarily overstress certain parts of the integrated circuit. When implemented at this clock frequency, some or many good ICs may be discarded. Conversely, some or many ICs may incorrectly pass.
Especially with the increasing complexity of modern chips with their increased functionality and higher operating speed, the use of one clock frequency for the testing of the entire IC may not be appropriate. Essentially, one test clock frequency may not be appropriate for all the cells in an IC. It is therefore desirable to have a scan application where the clock frequency may be adapted for testing of specific cells in an IC. For example, a highly complex cell that includes highly integrated digital signal processor circuitry may require a high test clock frequency to assure proper operation. But a less complex standard logic cell may not need to be stressed at high clock rates because it will never experience such stresses. In providing a test apparatus with a variable test clock frequency, an entire integrated circuit design process can be improved while assuring the at-speed functionality of the integrated circuits.
As test vector size increases, there are more demands to reduce test time while simultaneously maintaining the same or better test coverage. Because the scan test vector creates circuit disturbances during scan shift operation and test launch cycle, optimally, a slow speed shift operation is used during scan shift cycles. These disturbances are due to simultaneous switching activities cause by the shifting operation of scan data through the scan chain. During the at-speed scan test capture where time between the launch and the capture time is critical to detect at-speed delay defects, similar disturbances are also present. But for the test launch cycle to perform the at-speed test, reducing the test speed is necessary to avoid the simultaneous switching noises that would defeat the purpose of testing the device at-speed. The effects of the disturbances are often noted to the signal as a slow to propagate condition due to delays in switching circuitry from di/dt related ground noise and changes in slew rate from IR drop. These phenomenon starts to cause over test conditions during at-speed test using the scan vectors. Study of this issue shows that for the same signal path there are different signal propagation speeds due to the different simultaneous switching noises. A solution to this over test condition is to reduce a correct amount of delay caused by the disturbances from the at-speed launch. | {
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1. Field of the Invention
The present invention relates to a hybrid vehicle employing a parallel hybrid system, using both an internal combustion engine and an electric motor/generator as a propelling power source, and specifically to a driving torque control system for a hybrid vehicle with a parallel hybrid system.
2. Description of the Prior Art
As is generally known, later model passenger cars often employ a variable valve timing/lift control system to improve engine power output, for example, at low- and mid-speed range, and to improve fuel economy, and to reduce exhaust emissions. Generally, the variable valve timing control system is used to control an intake valve closing point or an intake valve close timing (herebelow abbreviated to "IVC") depending on engine speed and/or engine load. In recent years, there have been proposed and developed various parallel hybrid vehicles propelled by an internal combustion engine and/or an electric motor. The internal combustion engine of such a hybrid vehicle often adopts the previously-noted variable valve timing control system for altering the intake valve timing. One such parallel hybrid vehicle has been disclosed in Japanese Patent Provisional Publication No. 5-50865. In this type of parallel hybrid vehicles as disclosed in the Japanese Patent Provisional Publication No.5-50865, the output shaft of the engine is connected through a clutch to a motor shaft of an electric motor, to transmit driving torque through the motor shaft via a differential to drive wheels. In order to reduce fuel consumption, the parallel hybrid system executes a so-called idling stop where the engine is stopped during the vehicle standstill. The hybrid vehicle normally moves off on electric power of the electric motor. After the engine is started up, the hybrid vehicle is propelled by driving torque generated by the engine with the clutch engaged. | {
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The present invention relates to an accurate method and apparatus for controlling the flow rate of intake air of an engine.
There are two general types of methods for controlling fuel injection type engines. One is the air-first control system in which air taken into the cylinders of an engine (hereinafter referred to as xe2x80x9cengine intake air flow rate. The result of measurement by an air flow meter provided in a intake pipe is simply referred to as xe2x80x9cair flow ratexe2x80x9d) is measured and then the fuel is injected in an amount in accordance with the engine intake air flow rate. The other is the fuel-first control system in which an amount of fuel is defined in advance and an engine intake air flow rate in accordance with the same is supplied to the engine.
In either of the systems, it is important to achieve an air fuel ratio that realizes a state of combustion desirable for reduction of harmful components in exhaust gas and reduction of the amount of fuel consumption.
Referring to the air-first control system, methods for controlling an internal combustion engine aimed at maintaining an air fuel ratio accurately during a transient time are disclosed in, for example, Japanese patent Application Laid-Open 104930/1990 (hereinafter xe2x80x9cfirst prior artxe2x80x9d) and Japanese patent Application Laid-Open 134136/1992 (hereinafter xe2x80x9csecond prior artxe2x80x9d).
In the first prior art, a technique is disclosed in which an amount of fuel injection is determined by calculating a flow rate of intake air to an engine in accordance with a model of a intake pipe. In this case, a delay in an engine intake air flow rate at the time of a movement of a throttle valve caused by an accelerator pedal is calculated using pressure and engine speed information, and the amount of fuel injection is corrected in association with the delay of air. Since this method has had a problem in that amount for fuel correction is slow because the correction is calculated after a change in the opening of the throttle valve occurs, the second prior art provides a fuel injection controller by introducing a delay to the opening of the throttle valve relative to an acceleration pedal stepping-on amount to reduce the effect of the correction delay.
However, both of the conventional techniques are intended for the air-first control system and have the following problems when used for engines utilizing the fuel-first type control, e.g., direct injection in cylinder engines (hereinafter referred to xe2x80x9cDI enginesxe2x80x9d which imply both of spark ignition type and compression ignition type DI engines). In a DI engine, as its name implies, fuel is directly injected into the combustion chamber of the engine. It is therefore an engine convenient for fuel-first type control because an amount of fuel to be used for one cycle of combustion can be supplied each time. However, since the conventional technique is intended for the air-first type control system, there is a need for an apparatus and a method which can freely control the intake air flow rate of an engine for engines utilizing the fuel-first type control.
In the case of air-first control, the output of an engine is changed through a long process that starts with the changing of the opening of the throttle valve followed by a change in the pressure in the intake pipe, a change in the amount of engine intake air, the changing of the fuel flow rate in accordance with the air flow rate and an increase or decrease in the engine output. Since the output of an engine is mainly proportionate to the amount of fuel injection, such control can result in poor engine response because the amount of fuel injection must be changed after the engine intake air flow rate is changed even when the output is to be increased or decreased in a short period. This problem has not been regarded as a significant problem in conventional single point injection (SPI) systems in which fuel is injected upstream of the intake pipe (upstream of the throttle valve) and multi-point injection (MPI) systems in which fuel is injected into a manifold because the time for fuel to reach the combustion chamber of the engine is similar to the time for engine intake air from rate to change, which problem has been difficult to solve.
In the case of a DI engine, however, since it can supply an amount of fuel with better response to a delay of air compared to an SPI or MPI engine, the air-first type control system hinders the improvement of response because of the delay of air in one aspect thereof. While this can be solved by employing the fuel-first type control system, no controller and method have been provided which cause an air flow rate to follow up an amount of fuel injection with high accuracy.
Meanwhile, from the viewpoint of improved safety of automobiles, vehicle movement controlling techniques have been developed such as traction control to prevent slipping of wheels by adjusting engine output, and intelligent cruise control for preventing a collision with a car in front by adjusting engine output. Further, engine output is sometimes controlled in accordance with a gear change for automatic transmission, and engine output control at high speed and with high accuracy is required for such vehicle movement control.
Further, recent environmental regulations permit no increase in harmful components in exhaust gas attributable to fluctuation of an air fuel ratio, which has resulted in a need for reducing fluctuation of an air fuel ratio during acceleration and deceleration. This has resulted in a need for a method and an apparatus for controlling not only fuel but also an engine intake air flow rate.
The output of an engine is directly affected by the amount of fuel which is a source of thermal energy. That is, the output of an engine is determined by the amount of fuel. In the conventional techniques intended for the air-first control, the output of an engine has been indirectly adjusted with air flow rate. Therefore, accurate adjustment of engine output has involved repeated operations of varying the air flow rate first, injecting fuel in accordance therewith, observing the output and appropriately varying the air flow rate again in the case of an excess of shortage, and this has made it difficult to control the output accurately. In the case of a fuel-first control type engine, since the amount of fuel which determines the output is first determined, the engine output can be controlled with high accuracy only by controlling the intake air flow rate of the engine. However, no apparatus and method have been provided which transiently control the intake air flow rate of an engine with high accuracy.
It is an object of the present invention to provide an apparatus and a method for controlling engine intake air and a method for controlling output in which in order to control the output of an engine with high accuracy, when the intake air flow rate of the engine is determined (i.e., the output is determined) in accordance with the amount of fuel, an actual engine intake air flow rate is supplied accurately in accordance therewith.
In order to solve the above problems, there is provided an air flow rate controller which has an air flow rate detecting device for detecting an air flow rate, a throttle valve opening/closing device for opening and closing a throttle valve, and a calculating device to which the detection value of the air flow rate detecting device, the position of the throttle valve, the engine speed and a target engine intake air flow rate are input and in that the calculating device drives the throttle valve opening/closing device in advance such that the engine intake air flow rate agrees with the target engine intake air flow rate.
There is also provided a method for controlling engine intake air flow rate in which a time constant of a delay of response of the air flow rate is calculated and the throttle valve is controlled such that a delay of the engine intake air flow rate is corrected based on the calculated time constant to cause the engine intake air flow rate to follow up the target engine intake air flow rate.
The present invention specifically provides the methods and apparatuses described below.
The present invention provides a method for controlling the flow rate of intake air to an engine by controlling the opening of an electronically controlled throttle, in which a command value for the flow rate of intake air to the engine is calculated from a throttle position signal of the electronically controlled throttle provided in a intake pipe, an air flow rate signal detected by an air flow rate meter provided upstream of the electronically controlled throttle and an engine speed signal and in which a target engine intake air flow rate is calculated by finding an over-shooting amount for said electronically controlled throttle valve.
The present invention further provides a method for controlling the flow rate of intake air to an engine including an over-shooting operation in which a throttle position signal from the electronically controlled throttle, the signal of the air flow rate meter, the engine speed signal and the target engine intake air flow rate to be taken into the cylinders of the engine are input to a calculating device and in which the calculating device determines a time constant of a delay of response, calculates a target signal for an air flow rate meter for compensating for the delay of response based on the determined time constant of the delay of response and drives the electronically controlled throttle such that the signal of the air flow rate meter agrees with the target signal.
The present invention provides a method for controlling the flow rate of intake air to an engine by controlling the opening of an electronically controlled throttle, in which an engine intake air flow rate is obtained from a throttle valve position signal, an air flow rate signal of air flowing through a suction pipe and an engine speed signal; an intake air flow rate command value is calculated in accordance with an amount of fuel injection determined based on said intake air flow rate; a throttle valve position signal is obtained by adding an over-shooting amount to said intake air flow rate command value; and said calculation is repeated by obtaining an engine intake air flow rate from the throttle valve position signal, air flow rate signal and the engine speed signal.
The present invention further provides a method for controlling the flow rate of intake air to an engine in which said over-shooting amount is a compensating (correcting) value determined in advance for the delay of change of the intake air flow rate relative to the operation of the electronically controlled throttle.
The present invention provides a method for controlling the flow rate of intake air to an engine by controlling the opening of an electronically controlled throttle, in which an exhaust gas recirculation flow rate of exhaust gas recirculation for introducing the exhaust gas of the engine into a suction pipe is obtained based on a throttle valve position signal, an air flow rate signal of air flowing through the suction pipe and an engine speed signal; a position signal of an EGR valve is obtained by adding an over-shooting amount to a value corresponding to said exhaust gas recirculation flow rate; and said calculation is repeated by obtaining an exhaust gas recirculation flow rate from said throttle valve position signal, air flow rate signal and engine speed signal.
The present invention provides a method for controlling the flow rate of intake air to an engine having an electronically controlled throttle provided in a suction pipe for introducing air in the internal combustion engine for controlling air flow rate, an air flow rate meter provided upstream of the electronically controlled throttle for detecting the air flow rate, an engine speed meter for detecting engine speed, a calculating device and an EGR valve for an exhaust gas recirculation device for introducing exhaust gas from the internal combustion engine into the suction pipe, in which a throttle position signal from the electronically controlled throttle, an air flow rate meter signal, an engine speed signal, the flow rate of intake air to be taken into the cylinders of the engine and the flow rate of the exhaust gas to be taken into the cylinder of the engine are input to the calculating device; the calculating device determines a time constant for a first delay of response, calculates a target signal for the air flow rate meter to compensate for the delay of response based on the determined time constant for the first delay of response and drives the electronically controlled throttle such that the signal from the air flow rate meter agrees with the target signal; and the calculating device determines a time constant for a second delay of response and drives the EGR valve based on the determined time constant for the second delay of response to compensate for the delay of response of the exhaust gas that flows into the engine.
The present invention provides a device for controlling the flow rate of intake air to an engine having an electronically controlled throttle provided in a suction pipe for introducing air in the engine for controlling air flow rate, an air flow rate meter provided sequence of the electronically controlled throttle valve for detecting the air flow rate and an engine speed meter for detecting engine speed, having a configuration including a calculating device which obtains the flow rate of intake air to the engine from a throttle valve position signal, an air flow rate signal and an engine speed signal, calculates an intake air flow rate command value based on said intake air flow rate, obtains a throttle valve position signal by adding an over-shooting amount to said intake air flow rate command value and repeats said calculation by obtaining an engine intake flow rate from the throttle valve position signal, the air flow rate signal and engine speed signal.
The present invention provides a device for controlling the flow rate of intake air to an engine having an electronically controlled throttle provided in a suction pipe for introducing air in the engine for controlling air flow rate, an air flow rate meter provided upstream of the electronically controlled throttle valve for detecting the air flow rate and an engine speed meter for detecting engine speed, having a configuration including a calculating device which obtains a flow rate of intake air to the engine from a throttle valve position signal, an air flow rate signal and an engine speed signal, obtains an amount of fuel injection from said engine intake air flow rate, calculates an intake air flow rate command value in accordance with said amount of fuel injection, obtains a throttle valve position signal by adding an over-shooting amount to said intake air flow rate command value and repeats said calculation by obtaining an engine intake flow rate from the throttle valve position signal, the air flow rate signal and engine speed signal.
The present invention provides a device for controlling the flow rate of intake air to an engine having an electronically controlled throttle provided in a suction pipe for introducing air in the engine for controlling air flow rate, an air flow rate meter provided upstream of the electronically controlled throttle for detecting the air flow rate, an engine speed meter for detecting engine speed, a calculating device and an EGR valve for an exhaust gas recirculation device for introducing exhaust gas from the engine into the suction pipe, having a configuration including a calculating device to which a throttle position signal from the electronically controlled throttle, an air flow rate meter signal, an engine speed signal, the flow rate of intake air to be taken into the cylinders of the engine and the flow rate of the exhaust gas to be taken into the cylinder of the engine are input, in which the calculating device determines a time constant for a first delay of response, calculates a target signal for the air flow rate meter to compensate for the delay of response based on the determined time constant for the first delay of response and drives the electronically controlled throttle such that the signal from the air flow rate meter agrees with the target signal and in which the calculating device determines a time constant for a second delay of response and drives the EGR valve based on the determined time constant for the second delay of response to compensate for the delay of response of the exhaust gas that flow into the engine.
The present invention provides a method for controlling the output of an engine in which output required for an engine is controlled by a command from an acceleration pedal, in which the torque of an engine is controlled by determining an amount of fuel injection in advance based on an intake air flow rate obtained in a calculating portion, then determining an intake air flow rate command value based on said amount of fuel injection, and determining a target intake air flow rate by adding an over-shooting amount transiently to said intake air flow rate command value to control the opening of an electronically controlled throttle.
According to the invention, once a target engine intake air flow rate is given, a controller predicts the engine intake air flow rate and controls the opening of a throttle valve such to achieve the best approximation of the target engine intake air flow rate. Further, when a target engine intake EGR flow rate is given, an EGR valve is driven such that the EGR valve also achieves the target intake EGR flow rate. As a result, an actual engine intake air flow rate can quickly and accurately reach the target. It is therefore possible to obtain an intake air flow rate which is preferably used in a fuel-first control engine.
This also makes it possible to control the output of an engine taking advantage of the fuel-first type control system. | {
"pile_set_name": "USPTO Backgrounds"
} |
The effectiveness of a cache memory system is related to the organization of the cache memory. Three of the variables involved in a cache memory design are the cache size, the line size and whether the cache is a split or a unified cache. The cache size refers to the total amount of storage available. The line size refers to the number of words sharing a tag in the cache. All words within a line are moved into and out of the cache together. In a split cache, instructions and data are cached separately. By contrast, in a unified cache, no distinction is made between instructions and data.
These variables affect cache performance in manners which are not always straightforward. For example, as the cache size increases, cache performance also increases. However, the relationship between cache performance and cache size depends also upon many other factors, such as the software environment, including system software, code size, main memory architecture and latency.
Generally, a larger line size improves cache performance because, due to locality of reference, the larger number of words prefetched may reduce future memory accesses. However, for a given cache size, a larger line size decreases the number of lines which can be resident in the cache, thereby increases the possibility of thrashing.
Finally, since instructions and data exhibit different patterns of locality of reference, cache performance is affected by whether the cache memory system is organized as a split cache or a unified cache. In some applications, e.g. where a relative small block of instructions operates on a large randomized data space, a split cache has a performance advantage due to the higher instruction hit rates; in other applications, a unified cache has a performance advantage.
Thus, for a given application, an optimal cache configuration can be derived only after extensive evaluations. Such evaluations are necessary to assist the computer system designer to determine which cache configuration best meets his or her design objectives. Traditionally, evaluations are performed using simulations in software. However, such simulations are often limited in accuracy, flexibility and speed. Because of a computer system's inherent complexity, accurately modelling the operation of a cache memory in software is difficult. In particular, many asynchronous events of a real computer system, such as direct memory access (DMA) and exception conditions, are difficult to model in software. | {
"pile_set_name": "USPTO Backgrounds"
} |
The present invention relates to a method for inclining a chair seat, by which the backrest side of the seat is inclined upward when being seated, and to a chair having an inclinable seat.
Conventionally, such devices where the seat is caused to move forward in line with the rearward inclination of the backrest or the backrest side of the seat is inclined downward via a complicated link mechanism have been known as structures which do not adversely influence a human body when being seated.
In the arrangements described above, a chair is internally provided with a complicated link mechanism, and the number of manufacturing process is increased causing the production work to be slowed down and the production cost to be increased.
In a case where the seat is caused to move forward in line with rearward inclination of the backrest when a person is being seated, the backbone is not allowed to be elongated, burdens are likely to be imposed on the waist, and the center of gravity is moved from the buttocks to the knee side (the load of a person being seated is concentrated at the rear side of the femoral region in the vicinity of the knee). Therefore, the rear side of the femoral region near the knee is subjected to more pressure, thereby causing the blood vessels to be pressed and the circulation of the blood to be hindered. Accordingly, such a problem exists that fatigue and sensitivity to the cold can not be eliminated.
Furthermore, in a case where the backrest side seat is inclined rearward in line with rearward inclination of the backrest, the backbone is not allowed to be elongated as in the above case, and burdens are likely to be imposed on the waist, thereby causing the degree of angle formed by the femoral region and leg to be acute and the heel to be likely to be lifted up from the floor level. Therefore, the calf of the leg is apt to be strained, and the load of a person being seated is concentrated to the rear side of the femoral region in the vicinity of the knee causing a greater pressure to be exerted at the rear side of the femoral region. Accordingly, the blood vessels are pressed and the circulation of the blood is adversely affected, and such a problem exists that fatigue and sensitivity to the cold can not be eliminated.
Furthermore, from the biotechnological standpoint, it is well known that the blood vessels are pressed by the rear side of the femoral region in the vicinity of the knees which are subject to a load (the load being given due to the body weight) when being seated, thereby resulting in fatigue and sensitivity to the cold. | {
"pile_set_name": "USPTO Backgrounds"
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Machine-readable codes are known. The most widely known representatives thereof are barcodes (or bar codes, stripe codes, line codes), such as those used on many products. Known formats for such barcodes are EAN, UPC, IAN, JAN and codes from the 2/5 family, as well as codes in accordance with Code 39, Code 93, Codebar, Code 128, etc.
Moreover, “two-dimensional” (2D) barcodes are also known, which correspond, for example, to the code block format of Code 49, PDF417, or other formats in which encoded data can be resolved along two dimensions. Known two-dimensional codes are matrix codes, such as, e.g. Data Matrix codes, MaxiCodes, or the Aztec Code. Especially since 1994, the QR code is also a known representative of the 2D code, because it can encode a large amount of data, and also contains an error correction. It is also advantageous that QR codes can be used without licensing costs. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to linear bearings, such as used in heavy equipment, which provide linear load support and guidance particularly in applications where the area loads are too high to utilize the support and guidance through other kinds of rotational bearing elements, for example, due to the fact that the high area loads and resulting Hertzian stresses created in the contact zone would result in plastic deformation.
Linear bearing are used to support the lateral movement requested by the various processes and equipment such as bearing plates in mill windows of steel rolling mills. The bearing surfaces of those bearing plates are normally exposed to three major wear factors which include area loads, abrasion and corrosion. Wear, abrasion and corrosion typically lead to changes in the bearing plate geometry.
Abrasion and corrosion effectively increase the gap or play between two matching bearing surfaces and this increased play undesirably allows for relative movement of the equipment components. Due to the high dynamic energy of the moving components, the dynamic loads are proportional to the bearing play or gap. When dynamic loads reach a specific level, bearing plates transfer dynamic loads to bearing mounting and reference surfaces. The gap quickly grows and the output quality of the mill stand quickly degrades.
A direct relation between the hardness and stiffness of the material used for the bearing plates exists, because the hardness of any material is directly proportional to the stiffness and inflexibility of the material. A harder bearing plate material will deform a softer counterpart and as soon as the hardness of the bearing plate exceeds the hardness of the related mounting surface, the bearing plate will apply dynamic loads to its mounting counterpart with the potential to elastically and plastically deform the mounting surface. With this resulting deformation the connection between the bearing plate and the mounting surface will gradually yield gaps. These gaps permit, through a capillary effect, humidity and wetness to seep between the matching surfaces of the bearing.
Humidity and wetness between the matching surfaces, e.g., between the bearing plate and the mounting surface, will initiate another wearing factor called contact corrosion. Both mounting surfaces start transforming iron into iron oxide which then is washed out by more humidity pumped in by the relative movement under the constant dynamic loads created by the process. The result is a constantly increasing play or gap not only between the matching bearing surfaces of the equipment components involved but also between the bearing plates and their related mounting surfaces.
With sufficient moisture, a liquid layer is formed between the bearing plates and their related mounting surfaces. When high dynamic loads are applied to this liquid layer, cavitation occurs and leads to another wear mechanism. Cavitation increases the washout of the mounting surfaces which in turn gradually changes the geometry of those mounting surfaces. Due to the fact that mounting surfaces are at the same time the reference surfaces for the installation of the linear bearing plates, the equipment is gradually altered from its desired geometrical set-up.
Changes of the basic equipment geometry, for example a window of a rolling mill, will have a direct influence on the basic function of the equipment. In case of a rolling mill the changes of the mill window geometry change the geometrical relation of the rolls to each other which then in return has a direct influence on the rolling process as well as the geometry of the rolled products.
When any combination of the given process related limits are exceeded, the mill window geometry and reference base for the bearing plates has to be corrected. For such corrections there have been two basic processes. Prior to the present invention the play, gap or volume created be the erosion and wear and tear have been compensated by filling the gap with shims or injecting an appropriate resin material. Next, the surfaces are re-machined to new accuracy and the increased opening of the mill window compensated with the increasing of the bearing plate thickness. The selection of the correction method is driven by cost and time because the complete rolling mill has to be fully stopped to be able to apply the desired compensation technology. The quickest and cheapest approach has often been shimming or filling with resin and finally re-machining.
The prior art approach of applying the resin included steps of first mechanically adjusting the bearing plate geometry by using a combination of thrust and tension screws to provide a specific spacing between the bearing and mounting surface. Next, a seal was provided to surround the bearing plate and finally resin was injected between the bearing plate and the adjacent mounting surface. FIG. 10 illustrates such a process wherein a resin material 200 is injected between the housing liner 202 and the housing body 204. The resin material is injected under pressure and is maintained by a seal structure 206 surrounding the housing liner 202. The injected resin material 200 fills the interior volume defined between the housing liner 202 and the worn surface of the housing body 204. The success and durability of this methodology is strongly dependant on the preparation and cleanliness of the surfaces which are in direct contact with the resin. Due to the extremely hostile environment of the equipment to be repaired, the constant presence of oil and grease and also the dimensions and mostly vertical orientation of the mounting surfaces, it is very difficult to insure cleanliness of the resin-engaging surfaces necessary for rehabilitation of the bearing system. Due to the fact the resin has to be injected it has to be based on a 2-component epoxy which also needs a specific environmental temperature to be correctly applied. Also desirable temperature conditions for resin-setting are difficult, if not impossible, to maintain under the normal conditions of the facility.
There exist several negative effects of the application of plastic filling material or resin on the mounting surfaces of the mill housing body. Due to the difficulty of cleaning the mounting surface of the housing body, the contact between the resin and the worn out mounting surface is often not adequately maintained. Subsequent dynamic loads on the bearing plate further open a gap or create contact zones between the resin and the mounting surface allowing chemicals and liquid to seep in and cause corrosion. The plastic filling material or resin may also form bubbles which promote de-lamination and corrosion.
Thus, a need exists for a safe, economically efficient and robust approach so as remove the limitations of the prior art approaches to bearing maintenance and operation, particularly for linear bearings operating in hostile environments. | {
"pile_set_name": "USPTO Backgrounds"
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Various types of light modulators are known. These include, for example, Mach-Zehnder type modulators and electroabsorption modulators. The following literature references describe various Mach-Zehnder type modulators:
High-Speed Electrooptic Modulation in GaAs/GaAlAs Waveguide Devices, by Robert G. Walker, Journal of Lightwave Technology, Vol LT-5, No. 10, pp 1444-1453, October, 1987 and the references therein;
Broadband Y-branch electro-optic GaAs waveguide interferometer for 1.3 micrometers, by P. Buchmann et al, Applied Physics Letters, Vol 46, No. 5, pp 462-464 (1985);
Broad-Band Guided-Wave Electrooptic Modulators, by Richard A. Becker, The Journal of Quantum Electronics, Vol. QE-20, No. 7, July, 1984, pp 723-727;
The following product publications describe what is believed to be the state Mach-Zehnder optical modulators:
LC1000 Series GaAs Optical Modulators for D.C. to 50 GHz, GEC-Marconi, Materials Technology, Caswell Towcester, Northamptonshire, U.K.
2.5 GHz, 8 & 18 GHz Integrated Optical Amplitude Modulators, GEC Advanced Optical Products, West Hanningfield Road, Great Baddow, Chelmsford, Essex, U.K.
The following reference shows an optical switch which employs a multimode interference coupler:
Novel 1.times.N and N.times.N integrated optical switches using self-imaging multimode GaAs/AlGaAs waveguides by R. M. Jenkins et al., Applied Physics Letters, Vol 64 (6), Feb. 7, 1994, pp. 684-686. | {
"pile_set_name": "USPTO Backgrounds"
} |
The present invention relates to an improved process for the preparation of dihydroxydiphenylmethanes. More particularly, the present invention relates to a process for the selective preparation of 4,4xe2x80x2-dihydroxydiphenylmethane by reacting phenol with formaldehyde in the presence of microporous zeolite catalyst.
4,4xe2x80x2-dihydroxydiphenylmethane is useful as a starting material for the production of polycarbonate resins, polyester resins and epoxy resins and as a modifier and stabiliser for phenol resins.
Several methods are known in the art for the production of dihydroxydiphenylmethanes. Japanese Patent Jpn. Kokai Tokkyo Koho JP 0687775 (CA 121:57131) discloses a method for the condensation of phenol with aqueous formaldehyde using phosphotungstic acid which consists of 10:43:47 ratio of 2,2xe2x80x2-, 2,4xe2x80x2- and 4,4xe2x80x2-dihydroxydiphenylmethane isomers. EP 331, 172: CA 112:7160 discloses a method for reacting phenol with formaldehyde in the presence of an activated clay at 80xc2x0 C. for 2 hours to give 38.8% of 4,4xe2x80x2-, 15.8% of 2,2xe2x80x2-, and 38.4% of 2,4xe2x80x2-dihydroxydiphenylmethane and 7.0% oligomer JP 63, 238, 632: CA 116: 75045 discloses a method for reacting phenol with formaldehyde in the presence of activated clay catalyst to give 2,2xe2x80x2-, 2,4xe2x80x2-, and 4,4xe2x80x2dihydroxydiphenylmethane in the ratio of 17.1: 41.4:44.5.
U.S. Pat. No. 4,400,554: CA 99:175378 discloses a method for reacting phenol with formaldehyde in a two phase mixture in the presence of aqueous H3PO4 at 45xc2x0 C. to give 4,4xe2x80x2-, 2,4xe2x80x2- and 2,2xe2x80x2-dihydroxydiphenylmethane in a ratio of 55:37:8. U.S. Pat. No. 4,937,392 (1990) discloses a process for reacting phenol with formaldehyde in the presence of activated clay at 80xc2x0 C. under nitrogen atmosphere for two hours to give 4,4xe2x80x2-, 2,4xe2x80x2- and 2,2xe2x80x2-dihydroxydiphenylmethane in a ratio of 42.8:40.5:16.7. JP-B-39-26844 discloses a method for reacting phenol with formaldehyde in the presence of urea. U.S. Pat. No. 2,617,832 discloses a process for reacting phenol with dimethylol urea in the presence of an acidic catalyst.
A number of methods are known in the prior art for preparing dihydroxydiphenylmethane by reacting phenol with formaldehyde. Examples thereof include a method wherein an inorganic liquid acid such as hydrochloric acid, sulphuric acid or phosphoric acid is used as catalysts (cf. JP-A-58-177928; the term JP-A- as used herein refers to unexamined published Japanese patent applications. Also, cf. British patent No. 1,493,759 and U.S. Pat. No. 2,792,429).
However, the above methods have several disadvantages from the industrial point of view since the selectivity for 4,4xe2x80x2-dihydroxydiphenylmethane is low in each case. The catalyst is also homogeneous in some cases. Thus, a large amount of base is required to. neutralise the homogeneous acid catalysts causing problems in respect of the disposal of the resulting salts.
In view of the above-mentioned problems of homogeneous catalysts and low selectivity for 4,4xe2x80x2dihydroxydiphenylmethane in the prior art processes, it was felt necessary to develop an improved process for the production of dihydroxydiphenylmethanes and particularly 4,4xe2x80x2dihydroxydiphenylmethane with high selectivity from the condensation of phenol with formaldehyde which process does not have the disadvantages encountered by the prior art processes.
It is an object of the present invention to solve the above-mentioned problems by establishing a process for the advantageous preparation of dihydroxydiphenylmethane and particularly 4,4xe2x80x2-dihydroxydiphenylmethane in high selectivity.
It is another object of the invention to provide a process for the preparation of dihydroxydiphenylmethane and particularly 4,4xe2x80x2-dihydroxydiphenylmethane in high selectivity that allows recycling of the catalyst.
It is another object of the invention to provide a process for the preparation of dihydroxydiphenylmethane and particularly 4,4xe2x80x2-dihydroxydiphenylmethane in high selectivity that does not require disposal of inorganic byproducts.
The above and other objects of the present invention are achieved by the present invention in a novel manner by carrying out the condensation of phenol with a condensation agent, preferably formaldehyde in the presence of an inert solvent over a solid catalyst composite material aluminosilicate zeolite catalyst. Ideally, the zeolite catalyst is a microporous alumino-silicate zeolite catalyst composite and the reaction is carried out at a temperature of from 5 to 200xc2x0 C. The reaction is equally effective with other condensing agents as well.
Accordingly, the present invention relates to an improved process for the preparation of dihydroxydiphenylmethanes which comprises reacting phenol over a microporous alumino-silicate zeolite catalyst composite material in the presence of a condensing agent and a solvent at a temperature in the range of 5 to 200xc2x0 C. for a period between 0.1 to 24 hours at autogeneous pressure and separating the dihydroxydiphenylmethanes by any conventional method.
In one embodiment of the invention, the condensing agent is selected from the group comprising aqueous formaldehyde, paraformaldehyde and trioxane, the aqueous formaldehyde being most preferred.
In another embodiment of the invention, the solvent used is selected from the group comprising 1,2-dichloroethane, chloroform, CCl4, benzonitrile, nitrobenzene, acetonitrile, 1,2-dichlorobenzene or methylethylketone or mixtures thereof
In a further embodiment of the invention the zeolite catalyst composite material is selected from the group comprising zeolite H-beta, H-ZSM5, H-ZSM12, H-mordenite, H-Y, RE-Y and MCM-22.
In another embodiment of the invention, the ratio of the phenol to condensing agent is in the range between 5:1 to 10:1.
In one embodiment of the invention, wherein the zeolite and the phenol may be combined prior to reacting, added simultaneously at the time of the reaction.
In another embodiment of the invention, the zeolite and/or phenol are suspended in a solvent prior to addition to the condensing agent.
In one embodiment of the invention, the solvent used is selected from the group comprising of alcohol, aromatic or aliphatic hydrocarbons, ketones, chloroaromatic or nitroaromatic compounds, preferably methylethylketone.
In another embodiment of the invention, it is possible to selectively and efficiently prepare 4,4xe2x80x2-dihydroxydiphenylmethane while separating the ortho and the meta position products.
In another embodiment of the invention, the reaction may preferably be carried out at a relatively low temperature in the range of 20 to 200xc2x0 C.
The process of the invention is suitable as an industrial process for the production of 4,4xe2x80x2-dihydroxydiphenylmethane in high selectivity due to the use of non-hazardous solid aluminosilicate catalysts and the absence of any risk of explosion. The reactants and solvents that are used in the process of the present invention must be of high purity.
In the present invention, zeolite may be added to the reactant by different methods:
1. The zeolite and the phenol may be combined and added to the condensing agent prior to the reaction.
2. The zeolite and the phenol may be added simultaneously to the reaction system at the time of the reaction.
3. The zeolite may be suspended in a solvent, and a predetermined amount of phenol and the condensing agent being added thereto.
4. The zeolite may be suspended in the phenol and solvent, and a predetermined amount of condensing agent being added thereto.
Preferably, the catalyst composite material used is a microporous aluminosilicate zeolite H-beta type. The proportion of phenol to formaldehyde ratio, solvent and H-beta used ranges between 5:1 to 10:1 molar ratio and 0 to 50 ml and 0.01 to 100 g/mol phenol respectively.
The present invention will now be described with reference to the accompanying examples, which are merely illustrative and should not be construed as limiting the scope of the invention in any manner. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field
The present invention relates generally to actuators, and more particularly to hydraulic actuator devices suited for use in land vehicle suspension systems.
2. Description of Related Art
The use of servo actuators to control motion in land vehicle suspension systems offers the potential for improving performance, especially for off road application. For example, developers of military vehicles have been particularly interested in this technology to enable faster movement of military vehicles over rough battlefield terrain. Active suspension systems provide a smoother ride and greater maneuvering stability in both off-road and on-road vehicles than passive suspension systems.
Linear electromechanical actuators have been employed in active suspension system designs. Typical linear electromechanical actuators for active suspension systems consist of a rotary electric motor, an efficient means of providing mechanical advantage and converting rotary motion to linear motion, and a means of controlling the torque of the motor. For example, in one example of an active suspension electromechanical actuator, the mechanical advantage is a set of reduction gears and a rack and pinion pair to convert the rotary electromechanical torque to linear force. Typically, the linear actuator is supplemented by a passive spring (steel coil, air, or other) to support vehicle static weight. Although this combination rack and pinion based electromechanical actuator and supplemental spring works well, it is relatively long (poor ratio of actuator stroke to actuator length). This makes the rack and pinion actuator difficult to integrate into existing land vehicle suspension systems.
An alternate design approach utilizes hydraulic servo systems. Typical hydraulic servo systems have an electric motor, a hydraulic pump, a fluid reservoir, servo valves, flow passages, a hydraulic cylinder, and an array of pressure sensors and limit switches to control motion. This arrangement generally provides a good range of motion and can be configured to operate in all four control quadrants. The servo valve throttles the flow of fluid to control cylinder force, and in its best form controls fluid flow rate to the cylinder in a proportional manner by partially opening or throttling. In four quadrant systems, four-way servo valves are used to direct hydraulic pressure to one side of the cylinder and to vent the other side to the fluid reservoir. This arrangement is satisfactory in systems where motion is intermittent and where duty cycle is relatively low, such as construction equipment. In systems with high duty cycles, the conventional servo system offers low efficiency due to two major sources of losses. The first source of energy loss is in the servo valve, where throttling action is lossy, reducing pressure by dissipating energy. The second source of energy loss is in supply pressure regulation, typically accomplished by bleeding off or bypassing some of the flow to the reservoir to control the output pressure from the hydraulic pump. In systems where energy efficiency is important, pressure regulation is accomplished with a variable displacement hydraulic pump. However, this increased efficiency is at the expense of size, complexity and cost. | {
"pile_set_name": "USPTO Backgrounds"
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With respect to typical workplace washroom facilities, such as those facilities in a manufacturing plant, health care facility, office building, and the like, maintenance of the facilities is generally assigned to a maintenance team member that visits the facility on a scheduled or periodic basis to refill dispensers and ensure the cleanliness of the facility. The same person or persons may be assigned responsibility for a multitude of washroom facilities within building or business site.
In general, the maintenance person has little to no knowledge of the condition of the facility, especially the fullness state of the dispensers, until actually entering the facility. In this regard, the maintenance person must be prepared for completely empty states of the dispensers in the various facilities they are responsible for. The refill supplies are generally not stocked in the washroom facilities, and the maintenance person must carry sufficient refill supplies for a “worst case scenario”, which can be an overly burdensome task depending on the number of facilities and types of dispensers.
It has also been found that significant product wastage can be attributed to certain maintenance practices. For example, a towel dispenser may be one-third full when checked by a maintenance person. It is a common practice, however, to attempt to overstuff the dispenser with a full refill during a scheduled maintenance visit. This overstuffed condition often results in jamming of the dispenser or overuse of towels by the washroom patrons, for example when multiple towels are dispensed as a result of the overstuffed condition. If the dispenser has an overstuff-prevention device, it is also a practice to discard the remaining towels in the dispenser to that a new, full, refill can be loaded into the dispenser. Over time, such wastage can be quite expensive for the building proprietor.
The industry would benefit from a system and method wherein maintenance personnel are provided with specific instructions regarding the conditions and requirements of a particular washroom facility upon entering the respective facility that reduce the amount of wastage generated with conventional practices. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to polyester fibers having excellent heat stability and mechanical strength which are prepared by using aliphatic polyesters with biodegradability and sufficiently high molecular weights and specific melt properties for practical use.
Particularly, the present invention relates to monofilament, parallel fiber, multifilament, staple, crimped fiber and composite fiber, which are formed by using the above aliphatic polyesters.
2. Discussion of the Background
Synthetic (plastic) fibers have recently been used for industrial materials, cloths and nonwoven fabric and the like, the resulting waste of the large amount of plastics used in these materials cause pollution of rivers, oceans, soil and the like and is becoming a great social problem. To prevent such pollution the development of biodegradable plastics has been desired; for example, poly(3-hydroxybutylate) produced by fermentation methods using microorganisms, blends of general-purpose plastics and starch, a naturally occurring polymer, and the like are already known. The former polymer has a drawback in that it is poor in molding properties because the polymer has a heat decomposition temperature close to its melting point and a raw material efficiency is very bad because it is produced by microorganisms. On the other hand, since the naturally occurring polymer of the latter does not by itself have thermoplasticity, the polymer has defects in molding properties, and is greatly limited in its range of application.
On the other hand, although it is known that aliphatic polyesters are biodegradable, they have hardly been used because polymeric material sufficient enough to obtain practical molded product cannot be obtained. Recently, it has been found that a ring-opening polymerization of .epsilon.-caprolactone produces a higher molecular weight polymer, and proposed to use the polymer as a biodegradable resin. However, the resulting polymer is limited to only special applications because of a low melting point of 62.degree. C. and a high cost thereof. Further, although glycolic acid, lactic acid and the like are polymerized by a ring-opening polymerization of glycolide and lactide thereof to obtain polymers with higher molecular weights so as to be sometimes used as medical fibers and the like, the polymers are not used in great amounts as the above materials and the like because their decomposition temperatures are close to their melting point and they have defects in their molding properties.
Although most of these are applied to the industrial materials, cloths and nonwoven fabric, it is no exaggeration to say that high molecular weight polyesters (referring to polyesters having number-average molecular weights of at least 10,000) generally used for the plastics are limited to polyethylene terephthalate, a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol. Although there are cases of 2,6-naphthalenedicarboxylic acid being used instead of terephthalic acid, there are no reports of trials which obtained polymers with biodegradability.
Therefore, it is safe to say that there has been no concept of trying to make the fibers in practical use by using biodegradable aliphatic polyesters in which aliphatic dicarboxylic acid was used
One of the reasons why this application concept has not been thought of is felt to be that in spite of the required special forming conditions and physical properties for the above fibers, most of the above-mentioned aliphatic polyesters have melting points of 100.degree. C. or lower even if they are crystalline, and have poor heat stability when melted above that. Of further importance is that the properties, particularly mechanical properties such as tensile strength, of these aliphatic polyesters show markedly poor values even when they are the same level of number-average molecular weight as the above-mentioned polyethylene terephthalete, so just conceiving that the fibers having required strength and the like would be obtained was difficult.
Another reason seems to be that studies for improving the physical properties of the aliphatic polyesters by increasing their number-average molecular weights have not been sufficiently advanced because of their poor heat stability.
The object of the present invention is to provide polyester fibers prepared by the above-mentioned aliphatic polyesters as their components which have sufficient high molecular weights for practical use and excellent mechanical properties represented by heat stability and tensile strength, and which can be decomposed by microorganisms and the like, i.e., are biodegradable as one means of waste disposal so that they may be easily disposed of after the use thereof. | {
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1. Field of the Invention
This invention relates to a hard-coated chewing gum with dual polyol coatings (i.e., coatings of two or more polyols), having an extended shelf life.
2. Discussion of Related Art
This invention relates to a hard-coated chewing gum in which the hard coating is composed of two or more polyols, having an improved coating quality and extended shelf life.
Specifically, this invention relates to a chewing gum in pellet form, having one or more sequentially added coats of polyols, preferably selected from the group consisting of lactitol, maltitol, hydrogenated isomaltulose and erythritol. The hard pellets are prepared by coating a gum core with syrups of two or more polyols. The coated gum has improved coating quality and longer shelf life.
Chewing gums, including pellet chewing gums, are frequently enclosed with hard or soft coatings. Coatings provide an opportunity for the manufacturer to vary product characteristics such as taste, appearance and nutritional value. In recent years, efforts have been devoted to producing sugarless hard coatings for use in chewing gum. Sugarless coatings which have been investigated include coatings containing compounds such as xylitol, sorbitol, mannitol and hydrogenated starch hydrolysates.
Sugarless xylitol coated pellet gums have become very popular as products are being manufactured in Europe and Canada. The cost of xylitol is quite high, and partial replacement of the xylitol in the coating would be an advantage. Two polyols in the same coating solution cause problems in the coating process, but sequential coating of gum pellets with two solutions, each containing a polyol, one of which is xylitol, was found to be an acceptable process. U.S. patent application Ser. No. 07/857,577, filed Mar. 26, 1992, by Michael A. Reed and Ulesses P. Orr, now U.S. Pat. No. 5,270,061, taught sequential coating with a combination of hydrogenated isomaltulose and xylitol. Concurrently filed U.S. patent application Ser. No. 121,775, filed Sep. 15, 1993, by Michael A. Reed, Lindell C. Richey, Jeffrey S. Hook and Philip G. Schnell, now U.S. Pat. No. 5,376,389, discloses hard-coated chewing gum coated successively with xylitol and another polyol, preferably lactitol or maltitol.
U.S. Pat. No. 4,792,453, issued Dec. 20, 1988, to Michael A. Reed, Mansukh M. Patel and Vasek J. Kures, discloses a chewing gum having a sugarless chewing gum center coated with a syrup containing hydrogenated isomaltulose. The sugarless center may include various constituents such as water, an insoluble gum base, a bulking agent, a softener, an artificial sweetener and a flavoring agent. The sugarless chewing gum center of the reference has a water content of less than about 2.5 weight percent, preferably less than about 1.5 weight percent and most preferably less than about 1.0 weight percent. The use of a center having a low water content, is intended to prevent or reduce the tendency of the gum center from being a water donor to the hard coating.
Sugarless gums coated with hydrogenated isomaltulose-containing syrup possess excellent appearance, taste, texture, mouth feel and other desirable properties of hard coated chewing gums. Also, it has been found that the relatively anhydrous gum center has the capability of pulling moisture from the hydrogenated isomaltulose-containing coating, causing the coating to exhibit superior hardness. This moisture-pulling from the gum center is attributable, in large part, to the use of glycerin as a softener in the gum center. The moisture-pulling effect is the most pronounced in hard coated chewing gums which contain moderate or relatively high amounts of glycerin in the chewing gum center, on the order of from about 5 to about 15 percent by weight of the chewing gum center.
The tendency of glycerin to pull moisture from the hydrogenated isomaltulose-containing coating can operate as a disadvantage in certain pellet-shaped hard coated chewing gums which, due to their shape, are difficult to isolate from a moisture-containing environment by packaging. For example, pellet gum which is shaped like pillows is difficult to protect from moisture because it is difficult to form a good quality, low or non-moisture permeable package which is suitable for these pellets.
Conventional panning procedures generally coat with sucrose, but recent advances in panning have allowed the use of other carbohydrate materials to be used in the place of sucrose. Some of these components include, but are not limited to, dextrose, maltose, xylitol, hydrogenated isomaltulose and other new polyols or a combination thereof. These materials may be blended with panning modifiers including, but not limited to, gum arabic, maltodextrins, corn syrup, gelatin, cellulose type materials like carboxymethyl cellulose or hydroxymethyl cellulose, starch and modified starches, vegetable gums like alginates, locust bean gum, guar gum and gum tragacanth, insoluble carbonates like calcium carbonate or magnesium carbonate and talc.
Hydrogenated isomaltulose is a monohydrate. If a hydrogenated isomaltulose-containing coating on a pellet gum becomes too dry, e.g. due to the presence of glycerin, the coating becomes more hygroscopic and absorbs moisture from the surrounding atmosphere. This continuous drying and absorption of moisture from the atmosphere reduces the shelf life of the pellet gum by causing the coating to soften and lose its desirable texture, appearance and mouth feel. Thus, the coating itself must be sufficiently shelf stable against moisture absorption so as not to allow the coating to deteriorate during its shelf life.
Commonly assigned U.S. patent application Ser. No. 07/855,251, filed Mar. 23, 1992, by Michael A. Reed and Jeffrey S. Hook, now U.S. Pat. No. 5,248,508, entitled HARD COATED GUM WITH IMPROVED SHELF LIFE, discloses a chewing gum in pellet form which includes a center portion and an outer coating which contains hydrogenated isomaltulose.
Coating with xylitol is described in U.S. Pat. No. 4,105,801, issued Aug. 8, 1978, to Dogliotti; U.S. Pat. No. 4,127,677, issued Nov. 28, 1978, to Fronczowski et al.; U.S. Pat. No. 4,146,653, issued Mar. 27, 1979, to Mader et al.; U.S. Pat. No. 4,681,766, issued Jul. 21, 1987, to Huzinec et al.; U.S. Pat. No. 4,786,511, issued Nov. 22, 1988, also to Huzinec et al.; and U.S. Pat. No. 4,828,845, issued May 9, 1989, to Zamudio-Tena et al.
Patents and publications which discuss lactitol include U.S. Pat. No. 3,973,050, issued Aug. 3, 1976, to Hayashibara et al. (foods and drinks containing lactitol as a sweetener); U.S. Pat. No. 4,973,486, issued Nov. 27, 1990, to Matsumoto et al. (formulation of lactitol-containing food); and U.S. Pat. No. 4,999,058, issued Mar. 12, 1991, and U.S. Pat. No. 5,160,546, issued Nov. 3, 1992, both to Kawashima et al. (production of lactitol trihydrate; use in chewing gum, column 6 of each patent); British Patent 1,253,300, Hayashibara, published Nov. 10, 1971 (food materials containing lactitol); PCT published Patent Applications WO 90/06317, published Jun. 14, 1990, and WO 92/16542, published Oct. 1, 1992, both in the names of Heikkila et al. (preparation of crystalline lactitol and use as sweetening agent; use in chewing gums mentioned at page 1, lines 10-11 of '317 and page 5, line 13 of '542); Ir. I. H. Blankers, PURAC biochem bv, LACTY.RTM.-A UNIQUE REDUCED CALORIE SWEETENER (October, 1992); CCA biochem b.v., Application Information, Hard Panned Chewing Gum (undated, 1 page); CCA biochem b.v., Application Information, Starting Point Formulation for a Lacty.RTM.-containing Chocolate and Chewing Gum (undated, 1 page); CCA biochem b.v., INTERNATIONAL APPROVAL SITUATION FOR LACTITOL (1988)(1 page); CCA biochem bv, LACTY.RTM./A NEW REDUCED CALORIE SWEETENER (undated)(page 5, use in chewing gum); CCA biochem b.v., Product Data, LACTY.RTM.-M (undated, 1 page); Ir. C. H. den Uijl, CCA biochem by, LACTY.RTM., PROPERTIES AND APPLICATIONS OF THIS NEW REDUCED CALORIE SWEETENER (1987); (anon.) Lacty.RTM., A New Bulk Sweetener, CONFECTIONERY PRODUCTION, p. 656 (September 1990); PURAC biochem, LACTY.RTM. CONTAINING CHEWING GUM (undated, 1 page); and PURAC biochem, LACTY.RTM./A UNIQUE REDUCED CALORIE SWEETENER (undated)(page 5, use in chewing gum).
Patents and publications which discuss maltitol include U.S. Pat. No. 4,556,565, issued Dec. 3, 1985, to Arima et al. (sweetening compositions comprising maltitol); U.S. Pat. No. 4,623,543, issued Nov. 18, 1986, to Motegi et al. (non-hygroscopic candies containing maltitol); U.S. Pat. No. 4,717,765, issued Jan. 5, 1988, to Hirao et al. (production and use of maltitol anhydrous crystals; used in chewing gum in Example 12 in column 13); U.S. Pat. No. 4,840,797, issued Jun. 20, 1989, to Boursier (maltitol coating); U.S. Pat. No. 4,933,188, issued Jun. 12, 1990, to Cherukuri et al. (maltitol sweetening/bulking agent); U.S. Pat. No. 4,959,225, issued Sep. 25, 1990, to Wong et al. (sweetening compositions comprising maltitol); and U.S. Pat. No. 5,120,551, issued Jun. 9, 1992, to Yatka et al. (maltitol syrup); European Patent Publication 0,390,299, published Oct. 10, 1990, in the names of Bakal et al. (foodstuffs containing maltitol); and Japanese Patent Publications 53 (1978)-127,858, published Nov. 8, 1978 in the names of Fukuda et al. (chewing gum which may include maltitol) and 4 (1992)-287,659, published Oct. 13, 1992, in the names of Shigeni et al. (low-calorie sweetener containing maltitol).
Hydrogenated isomaltulose is made and sold under the trademark PALATINIT.RTM. by Palatinit Sussungsmittel GmbH, Germany. Publications which discuss hydrogenated isomaltulose include PCT applications WO 89/03170, published Apr. 20, 1989; WO 90/06061, published Jun. 14, 1990; WO 90/07864, published Jul. 26, 1990; WO 90/13994, published Nov. 29, 1990; and WO 91/03147, published Mar. 21, 1991, all in the names of Yatka et al., which disclose the use of Palatinit.RTM. hydrogenated isomaltulose coatings; Palatinit.RTM.-INFOPAC, Palatinit Sussungsmittel GmbH (synergistic effects appear when PALATINIT.RTM. hydrogenated isomaltulose is mixed with other sugar alcohols, for example, xylitol, sorbitol, or Lycasin, or when PALATINIT.RTM. hydrogenated isomaltulose is sweetened with sweetening agents (saccharin, cyclamate, aspartame); also formula for chewing gum containing PALATINIT.RTM. hydrogenated isomaltulose) and Palatinit.RTM. Coating Literature, Palatinit Sussungsmittel GmbH (coating dragees and panned goods with PALATINIT.RTM. hydrogenated isomaltulose).
Patents and publications which discuss erythritol include U.S. Pat. No. 4,902,525, issued Feb. 20, 1990, and U.S. Pat. No. 5,080,916, issued Jan. 14, 1992, both to Kondou; Japanese Patent Publications 64 (1989)-51,045, published Feb. 27, 1989, in the name of Kondo; 1 (1989)-225,458, published Sep. 8, 1989, in the names of Katsuragi et al.; 2 (1990)-104,259, published Apr. 17, 1990, in the name of Ito; 4 (1992)-287,658, published Oct. 13, 1992, in the name of Kondo; and 4 (1992)-287,659, published Oct. 13, 1992, in the name of Shigeni et al. (sweetening compositions containing meso-erythritol); U.S. Pat. No. 5,120,550, issued Jun. 9, 1992, to Van der Schueren (chewing gum made with sweetening agent containing erythritol and a liquid sugar); and European Patent Applications 0,009,325, published Apr. 2, 1980, in the name of Beerboom (reducing dental caries with sugarless chewing gum made with erythritol); 0,497,439, published Aug. 5, 1992, in the names of Gonze et al. (sweetener employing spray-dried erythritol); 0,511,761, published Nov. 4, 1992, in the names of Rapaille et al. (sweetening compositions containing erythritol); and 0,530,995, published Mar. 10, 1993, in the names of Gonze et al. (lozenge containing sweetener which is all or partly erythritol or maltitol).
Other patents and publications which may be of interest include U.S. Pat. No. 5,017,400, issued May 21, 1991, to Olinger et al. (non-cariogenic sweetener containing xylitol and maltitol; used in chewing gums, see Example I in columns 5-6); U.S. Pat. No. 5,135,761, issued Aug. 4, 1992, to Dave et al. (coated chewing gum with emulsifier subcoat); U.S. Pat. No. 5,144,024, issued Sep. 1, 1992, to Pepper et al. (shelf stable liquid xylitol compositions comprising polyols such as maltitol); U.S. Pat. No. 5,171,589, issued Dec. 15, 1992, to Richey et al. (coated chewing gum polished with colored wax); and PCT published Patent Application WO 91/07100, published May 30, 1991, in the names of Oravainen et al. (hard candy containing xylitol and optionally maltitol or lactitol). See also PCT Patent Application PCT/US92/11195, filed Dec. 23, 1992, in the names of Yatka et al., published Aug. 4, 1994 as PCT Application WO 94/16574 (chewing gum containing lactitol). | {
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This section provides background information related to the present disclosure which is not necessarily prior art.
Batteries, whether disposable or rechargeable, provide the energy source for a wide range of portable devices. There is growing interest in so-called smart batteries, which communicate over a wired communication interface, known as the System Management Bus or SMBus to perform power management operations. In a typical smart battery system, an integrated circuit in the battery pack monitors the battery and reports information to external devices via the SMBus. The reported information might include battery type, model number, manufacturer, discharge rate, predicted remaining capacity, temperature and voltage (temperature and voltage being relevant to fast-charging).
In order to use this SMBus information, the device into which the battery is installed must be designed to make specific use of the information. For example, a laptop computer or mobile phone might be designed to report the battery charge remaining as a graphical icon on the device display screen. Similarly, battery charges incorporated into these devices make use of the temperature and voltage information in order to provide safe fast-charging.
While devices equipped with SMBus-enabled smart batteries are certainly advantageous, the conventional smart battery technology leaves thousands of products without any practical way to benefit from this technology. The simple flashlight, for example, is ill-equipped to take advantage of smart battery technology, for the simple on-off function of the flashlight has no way to utilize information coming from the SMBus. Moreover, even more sophisticated products, such as digital cameras, which might potentially use SMBus information, may still lack important charge level awareness information or lack the ability to communicate that information in a manner that is intuitive to the user.
When they think about it at all, most users make assumptions about the battery charge levels within their devices. The mindfully prepared user removes batteries and tests them frequently, or uses fresh batteries before embarking on an adventure where fresh batteries and charging stations will be unavailable. The careless or uninformed user simply proceeds on the adventure without giving battery charge level a second thought—until the batteries fail, perhaps far from civilization. | {
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1. Field of the Invention
This invention relates to a laminate having an internal member responsive to stimuli; to an interlayer composite to seal the edge portions of the laminate; optionally to bus bars arranged on the internal member to eliminate hot spots at end portions of the bus bars; to methods of fabricating the laminate using the interlayer composite, and optionally the arrangement of the bus bars, and, in particular, to a heatable transparent laminate, e.g. an automotive windshield having an interlayer composite having a lead assembly to prevent ingress of air into the laminate and to provide external electrical access to bus bars optionally arranged to eliminate hot spots at end portions of the bus bars, and to methods of making the heatable laminate.
2. Discussion of the Technology
Automotive heatable windshields, e.g. of the type disclosed in U.S. Pat. No. 4,820,902 include two glass sheets laminated together by a plastic interlayer, usually a sheet of polyvinyl butyral (“PVB”). A pair of spaced bus bars between the glass sheets are in electrical contact with an electrically conductive member, e.g. a sputtered electrically conductive coating of the type disclosed in European Patent Application No. 00939609.4, applied to a major surface of one of the glass sheets or a plurality of electrically conductive filaments of the type disclosed in U.S. Pat. No. 5,182,431. Each of the bus bars is electrically accessible by an external lead to pass current from a power source through the bus bars and the coating to electrically heat the coating and heat by conduction the inner and outer surfaces of the windshield. The heated windshield surfaces attain a temperature sufficient to remove fog, and melt snow and ice. As can be appreciated, heatable windshields are practical, and in some geographical areas are a requirement, during the winter season.
In the fabrication of commercially available automotive windshields, an electrically conductive coating, usually a sputtered electric conductive coating is applied to a flat piece of glass. The flat piece of glass is cut to provide a blank. A pair of spaced bus bars is provided on the coating by silk-screening an electrically conductive ceramic paste onto the conductive coating as discussed in U.S. Pat. Nos. 4,654,067 and 4,718,932 or by using metal foil bus bars as discussed in U.S. Pat. Nos. 5,418,026; 5,466,911, and 5,850,070. A second glass blank has a black band silk-screened onto the marginal edges. The black band shields the underlying adhesive securing the windshield to the automotive body from ultraviolet (“UV”) radiation that can deteriorate the adhesive and provides an aesthetically pleasing appearance.
The coating and silk screened bus bars are normally applied to a surface of a blank that is designated as the No. 3 surface of the laminated windshield, i.e. the outer surface of the inner glass blank of the laminated windshield as mounted in the vehicle. The black band is normally applied to a surface of a blank that is designated as the No. 2 surface of the laminated windshield, i.e. the inner surface of the outer glass blank of the laminated windshield. The glass blank having the coating and the bus bars, and the glass blank having the black band are each shaped for a contoured windshield. A sheet of plastic interlayer, usually polyvinyl butyral is positioned between the shaped glass sheets (referred to as a “windshield subassembly”). When the bus bars are not silk screened on the coating, e.g. when metal foil bus bars are used, the bus bars are positioned between the interlayer and the coating.
The edges of the windshield subassembly are edge sealed in the usual manner, e.g. moving the windshield subassembly through nipper rolls or placing a vacuum channel around the periphery of the windshield subassembly and pulling a vacuum while heating the windshield subassembly. Thereafter the edge sealed windshield subassembly is placed in an air autoclave; heat and pressure are applied to the edge sealed subassembly to provide a laminated windshield. The seal around the periphery of the edge sealed windshield subassembly is formed to prevent air from moving between the glass sheets during the removal of the vacuum channel after the edge sealing operation and/or during the autoclaving.
For a general discussion regarding heatable windshields reference may be had to U.S. Pat. Nos. 3,789,191; 3,789,192; 3,790,752; 3,794,809; 4,543,466, and 5,213,828.
As can be appreciated, eliminating the silk screening of bus bars eliminates a manufacturing operation and all the limitations associated therewith such as the inventory of silk screens for each windshield design, handling and inventory of the ceramic conductive paste, and maintaining efficient operation of the silk-screening machines. Using metal foil bus bars eliminates the limitations associated with silk screening bus bars; however, there are other limitations in the use of metal foil bus bars. More particularly, the metal foil bus bars are in surface contact with the conductive coating. A lead, usually an extension of the bus bars, extends out of the laminate to provide electrical access to the bus bars. The surface of the lead that is a continuation of the surface of the bus bar in contact with the conductive coating and the adjacent portions of the glass sheet provide an air path. During the removal of the channel from, and/or during the autoclaving of, the edge sealed windshield subassembly air moves through the air path between the glass blanks. As can be appreciated by those skilled in the art of laminating windshields, the air moving between the blanks causes delamination. Depending on the severity of the delamination, the windshield may have to be discarded or replaced.
It would be advantageous therefore to use metal foil bus bars to eliminate the drawbacks of silk screening while eliminating the present drawbacks of metal foil bus bars. | {
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Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).
A wireless communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs). A UE may communicate with a BS via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a new radio (NR) BS, a 5G Node B, and/or the like.
The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless communication devices to communicate on a municipal, national, regional, and even global level. New radio (NR), which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or single carrier frequency division multiplexing (SC-FDM) (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and NR technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies.
A wireless communication device, such as a UE, may transmit information to a recipient, such as another UE, a base station, and/or the like. In some cases, the UE may transmit the information on multiple, different antennas, using an approach such as transmit diversity (e.g., Spatial Orthogonal Resource Transmit Diversity (SORTD), etc.), multiple-input multiple-output (MIMO), and/or the like. In some aspects, when configuring transmit diversity, the UE may assign one or more respective resource blocks for each transmit antenna to transmit the signals. For example, each resource element of a first resource block may be assigned to a first antenna (e.g., for symbols to be transmitted by the first antenna), and each resource element of a second resource block may be assigned to a second antenna (e.g., for symbols to be transmitted by the second antenna). However, in such a case, there may be limited frequency diversity of the signals, since each antenna is assigned a respective set of contiguous resource elements. This may lead to degraded performance and increased interference. | {
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This invention relates to newly identified polynucleotides, polypeptides encoded by such polynucleotides, the use of such polynucleotides and polypeptides, as well as the production of such polynucleotides and polypeptides. More particularly, the polypeptide of the present invention is human MutT2, sometimes hereinafter referred to as xe2x80x9chMutT2.xe2x80x9d The invention also relates to inhibiting the action of such polypeptides.
Errors in DNA replication lead to spontaneous mutations. Elevated spontaneous mutations lead directly to abnormal cell growth and disorders, such as tumors. A certain portion of spontaneous mutagenesis is caused by endogenous free radicals which are generated by normal cellular metabolism. The free radicals cause oxidative damage to DNA and may be an important determinant in longevity (Ames, B. N. and Gold, L. S., Mutat. Res., 250:3-16 (1991)).
Oxygen radicals damage chromosomal DNA, causing cell death and inducing mutations. One type of DNA damage caused by oxygen radicals is an oxidized form of the guanine base (8-oxoguanine) (Shibutani, S., et al., Nature, 349:431-4 (1991)). This oxidized form of guanine can pair with cytosine and adenine, and G:C to T:A transversions follow (Tkeshelashvili, L. K., et al., J. Biol. Chem., 266:6401-6406 (1991)). Thus, active oxygen species produced by cellular metabolic intermediates are sufficient to oxidize the guanine base of the DNA, even in normally growing cells.
Oxidation of guanine proceeds also in a form of free nucleotide, and an oxidized form of dGTP, 8-oxo-dGTP, is a potent mutagenic substrate for DNA synthesis (Maki, H. and Sekiguchi, M., Nature, 355:273-275 (1992)). In contrast with the consequence of 8-oxoguanine arising in DNA, 8-oxo-dGTP can induce A:T to C:G as well as G:C to T:A transversions (Cheng, K. C., et al., J. Biol. Chem., 267:166-172 (1992)).
In E. coli there are mechanisms that prevent mutations caused by oxidation of the guanine base in both DNA and free nucleotide forms. Oxidized DNA is repaired by the MutM protein, which possesses activity to remove the 8-oxoguanine base from the damaged DNA. On the other hand, 8-oxo-dGTP can be eliminated from the nucleotide pool by the mutT protein, which hydrolyses the mutagenic nucleotide to 8-oxo-dGMP (Maki, H. and Sekiguchi, M., Nature, 355:273-275 (1992)). In the mutT mutant, 8-oxo-dGMP misincorporated opposite to dA residues of template may be removed by the mutM protein before the next round of DNA replication. The mutT protein, therefore, degrades the potent mutagenic substrate, 8-oxo-dGTP to the harmless monophosphate substrate to ensure proper DNA synthesis. Mutations in the E. coli mutT gene cause an increase of the occurrence of A:T to C:G transversions 100-10,000-fold over the wild-type level (Akiyama, M., et al., Mol. and Gen. Genet., 206:9-16 (1987)).
Eukaryotes and mammals also have an enzyme which hydrolyses oxidized nucleotides. The enzyme is homologous to the E. coli mutT gene. A significant amount of 8-oxoguanine is formed in the chromosome DNA of mammalian cells and most of the damaged nucleotides are excised from the DNA and excreted into the urine (Ames, B. N. and Gold, L. S., Mutat. Res., 250:3-16 (1991) and Shigenaga, M. K., et al., PNAS, 86:9697-9701 (1989)).
The spontaneous oxidation of dGTP forms 8-oxo-dGTP which can be inserted opposite dA and dC residues of template DNA with almost equal efficiency, and the mutT protein specifically degrades 8-oxo-dGTP to the monophosphate. Thus, elimination of the oxidized form of guanine nucleotide from a nucleotide pool is important for the high fidelity of DNA synthesis.
The polypeptide of the present invention corresponds in size and amino acid sequence homology to human MutT and has, therefore, been preliminarily characterized as human MutT2.
In accordance with one aspect of the present invention, there is provided a novel mature polypeptide which is hMutT2, as well as biologically active and diagnostically or therapeutically useful fragments, analogs and derivatives thereof.
In accordance with another aspect of the present invention, there are provided isolated nucleic acid molecules encoding hMutT2, including mRNAs, DNAs, cDNAs, genomic DNA as well as biologically active and diagnostically or therapeutically useful fragments, analogs and derivatives thereof.
In accordance with yet a further aspect of the present invention, there is provided a process for producing such polypeptide by recombinant techniques which comprises culturing recombinant prokaryotic and/or eukaryotic host cells, containing a hMutT2 nucleic acid sequence, under conditions promoting expression of said protein and subsequent recovery of said protein.
In accordance with yet a further aspect of the present invention, there is provided a process for utilizing such polypeptide, or polynucleotide encoding such polypeptide for therapeutic purposes, for example, to prevent and treat diseases associated with errors in DNA replication and abnormal cell growth, for example that present in a tumor and a cancer, by specifically hydrolyzing oxidized nucleoside triphosphates, in particular, 8-oxo-dGTP, to the corresponding monophosphate for high fidelity of DNA synthesis.
In accordance with another aspect of the present invention there are provided nucleic acid probes comprising nucleic acid molecules of sufficient length to specifically hybridize to hMutT2 sequences.
In accordance with yet a further aspect of the present invention, there are provided antibodies against such polypeptides.
In accordance with another aspect of the present invention there is provided a method of diagnosing a disease or a susceptibility to a disease, for example, abnormal cellular growth, related to a mutation in hMutT2 nucleic acid sequences and the protein encoded by such nucleic acid sequences.
In accordance with yet another aspect of the present invention, there are provided antagonists to such polypeptides, which may be used to inhibit the action of such polypeptides, for example, in the treatment of tumors.
In accordance with yet a further aspect of the present invention, there is provided a process for utilizing such polypeptides, or polynucleotides encoding such polypeptides, for in vitro purposes related to scientific research, synthesis of DNA and manufacture of DNA vectors.
These and other aspects of the present invention should be apparent to those skilled in the art from the teachings herein. | {
"pile_set_name": "USPTO Backgrounds"
} |
The present invention relates generally to methods and devices for drug delivery and analyte extraction, and specifically to medical methods and devices for puncturing the outer layer of living skin and to methods and devices for transdermal drug delivery and analyte extraction.
A number of different methods have been developed to perform transdermal drug delivery and/or analyte extraction, including passive diffusion of a drug or analyte between a skin patch and skin, as well as active processes such as iontophoresis, sonophoresis, electroporation, and chemically enhanced diffusion. These methods are primarily used for generating transdermal movement of small molecules, but generally do not enhance the motion of large molecules through the 10-50 micron thick outermost layer of the skin, the stratum corneum epidermidis.
In an article, xe2x80x9cMicromachined needles for the transdermal delivery of drugs,xe2x80x9d IEEE 11th Annual International Workshop on Micro-Electro-Mechanical Systems (1998), pp. 494-498, which is incorporated herein by reference, Henry et al. discuss a method of mechanically puncturing the skin with microneedles in order to increase the permeability of skin to a test drug. In the article, microfabrication techniques are described to etch an array of needles in silicon, and experiments performed on cadaver skin with the needle array demonstrated an increase in permeability subsequent to puncture of the skin. The needles are created with a predetermined length, and penetrate to the same depth from the skin surface, regardless of the local thickness of the stratum corneum. It is known that if the needles are longer than the local thickness, then the underlying epidermal tissue may be injured, while if the needles are too short, channel formation through the stratum corneum may be incomplete.
U.S. Pat. Nos. 4,775,361, 5,165,418, and 5,423,803, and PCT Publication WO 97/07734, the disclosures of which are incorporated herein by reference, describe methods of using laser pulses to locally heat the stratum corneum to about 120xc2x0 C., thereby causing local ablation, in order to cause a single hole to develop in the stratum corneum through which large molecules may pass. Whereas some selectivity of ablation depth can be attained by varying the wavelength of the laser pulse, no feedback mechanism is disclosed whereby the laser pulses are terminated upon generation of the necessary damage to the stratum corneum.
PCT Publication WO 97/07734 also discloses thermal ablation of the stratum corneum using an electrically resistive element in contact with the stratum corneum, such that a high current through the element causes a general heating of tissue in its vicinity, most particularly the stratum corneum. As above, no means are disclosed to terminate current flow upon sufficient disruption of the stratum corneum. Additionally, thermal characteristics of skin vary highly across different areas of an individual""s skin, as well as among a group of subjects, making optimal thermal dosages, which produce the desired ablation without causing pain, very difficult to determine. Lastly, increasing transdermal molecular flow by increasing the permeability of the stratum corneum, whether using microneedles, laser energy, or resistive heating of tissue, is inherently a two step process: (a) position apparatus to generate holes, and (b) apply a patch to the skin, through which the molecules will flow.
Electroporation is also well known in the art as a method to increase pore size by application of an electric field. This process is described in an article by Chizmadzhev et al., entitled xe2x80x9cElectrical properties of skin at moderate voltages,xe2x80x9d Biophysics Journal, February, 1998, 74(2), pp. 843-856, which is incorporated herein by reference. Electroporation is disclosed as a means for transiently decreasing the electrical resistance of the stratum corneum and increasing the transdermal flux of small molecules by applying an electric field to increase the size of existing pores. Electroporation generally does not produce pores of sufficient diameter to pass large molecules therethrough. Additionally, optimal voltage profiles are difficult to determine because of naturally occurring variations as described hereinabove, as well as the lack of an accurate feedback mechanism to indicate achievement of the desired pore enlargement. If excessive voltage is applied, an irreversible breakdown occurs, resulting in damage to the skin and possible sensations of pain.
U.S. Pat. No. 5,019,034 to Weaver et al., whose disclosure is incorporated herein by reference, describes apparatus for applying high voltage, short duration electrical pulses on the skin to produce electroporation, and states that xe2x80x9c. . . reversible electrical breakdown . . . along with an enhanced tissue permeability, is the characteristic effect of electroporation.xe2x80x9d
It is an object of some aspects of the present invention to provide improved apparatus and methods for transdermal delivery of an active substance.
It is a further object of some aspects of the present invention to provide improved apparatus and methods for transdermal analyte extraction.
It is yet a further object of some aspects of the present invention to provide improved apparatus and methods for creating narrow channels through the stratum corneum of living skin by puncturing.
It is still a further object of some aspects of the present invention to provide improved apparatus and methods for reducing sensation and minimizing damage to skin underlying the stratum corneum during channel creation.
It is an additional object of some aspects of the present invention to provide improved apparatus and methods for controlling the timing of channel creation.
It is yet an additional object of some aspects of the present invention to provide improved apparatus and methods for regulating channel creation responsive to properties of the skin.
It is another object of some aspects of the present invention to provide improved apparatus and methods for puncturing the skin and/or transdermally delivering an active substance and/or transdermally extracting an analyte, using a miniature, self-contained device.
It is yet another object of some aspects of the present invention to provide improved apparatus and methods for transdermally delivering an active substance using a standard medical skin patch.
In preferred embodiments of the present invention, a device for enhancing transdermal movement of a substance comprises: (a) a skin patch, with at least two electrodes in contact with the skin of a subject; and (b) a control unit, coupled to the patch, which causes a current to pass between the electrodes through the stratum corneum epidermidis, in order to generate at least one micro-channel in the stratum corneum to enable or augment transdermal movement of the substance. Preferably, the control unit comprises switching circuitry to control the magnitude and/or duration of the electric field at the electrode.
The term xe2x80x9cmicro-channelxe2x80x9d as used in the context of the present patent application and in the claims refers to a pathway generally extending from the surface of the skin through all or a significant part of the stratum corneum, through which pathway molecules can diffuse. Preferably, micro-channels allow the diffusion therethrough of large molecules at a greater rate than the same molecules would diffuse through pores generated by electroporation. It is believed that such micro-channels are formed due to local power dissipation leading to ablation of the stratum corneum when an electric field of sufficient magnitude is applied to a small area of the skin, in contact with the electrodes, for a certain period of time. Unlike methods of electrically-promoted drug delivery known in the art, such as iontophoresis and electroporation, the present invention enables relatively large channels to be formed, through which even large molecules of the active substance can pass rapidly, without the necessity of ionizing or polarizing the molecules.
The current flow between the electrodes can be described as having two components: (a) a perpendicular component, which is generally perpendicular to the skin surface (and, if the associated electric field is sufficiently large, may cause current to go through the stratum corneum into the underlying epidermal tissue and dermis); and (b) a lateral component, generally parallel to the skin surface, which remains generally within the stratum corneum. Substantially all of the current generated at one electrode ultimately emerges from the skin and is taken up by an adjacent electrode.
In preferred embodiments of the present invention, methods and/or apparatus are employed to increase the relative value of the lateral component with respect to the perpendicular component. In general, the stratum corneum epidermidis (the superficial layer of the epidermis) demonstrates a significantly higher resistance to the passage of molecules therethrough than does the underlying epidermal tissue. It is therefore an object of these preferred embodiments of the present invention to form micro-channels in the stratum corneum by ablating the stratum corneum in order to increase conductance of the substance therethrough, and to generally not directly affect or damage epidermal tissue underlying the stratum corneum or in the innervated dermis. Additionally, limiting current flow substantially to the non-innervated stratum corneum is expected to decrease or eliminate the. subject""s sensations, discomfort, or pain responsive to use of the present invention, particularly as compared with other procedures known in the art.
A voltage applied between two electrodes on the skin generates an electric field that is to a large extent confined to the volume in a vicinity of the electrodes. Thus, electrodes which are widely spaced produce a field and current flow responsive theretoxe2x80x94which extends relatively deep into the skin. Conversely, electrodes which are closely spaced do not generate significant current flow at deeper layers. Therefore, in some preferred embodiments of the present invention, the electrodes of the device are separated by distances smaller than about 100 microns (but for some applications by distances of up to approximately 500 microns), in order to generate a current flow which is largely confined to a thin layer, comprising most or all of the stratum corneum. This effectively results in a desired larger value of the ratio of the lateral component to the perpendicular component, as described hereinabove.
In some of these preferred embodiments of the present invention, a high-frequency AC current with an optional DC current added thereto is applied between the closely-spaced electrodes in order to generate lateral capacitive currents in the stratum corneum and to cause breakdown and micro-channel formation in the stratum corneum.
In some preferred embodiments of the present invention, the patch comprises an array of electrodes, preferably closely-spaced electrodes, which act together to produce a high micro-channel density in an area of the skin under the patch. Preferably, the control unit and/or associated circuitry sequentially or simultaneously evaluates the current flow through each electrode, or a subset of the electrodes, in order to determine when one or more micro-channels have formed responsive to the applied field. Responsive thereto, the control unit discontinues application of the field. Since the formation of a micro-channel is typically marked by a local drop in electrical resistance of the skin, the control unit may, for example, reduce the voltage or current applied at any electrode wherein the current has exceeded a threshold. By reducing current flow upon or shortly after micro-channel formation, the likelihood of skin burns or pain sensations is minimized.
In some preferred embodiments of the present invention, a relatively high voltage is applied to the electrodes initially, so as to induce formation of micro-channels through the skin. A property of the current flow is detected, and the current is reduced or terminated when the property reaches a predetermined threshold. Preferably, the detected property of the current flow is secondary to changes in a conduction property of the skin, responsive to formation of one or more micro-channels through the stratum corneum.
Alternatively or additionally, a time-varying voltage V(t), characterized, for example, by the formula V(t)=V0+ktn, is applied between a first electrode and a second electrode in the skin patch until a shut-off signal is generated. (Constants k and n are nonnegative.) Other forms of V(t) may include a sinusoid, an exponential term, or a series of pulses. A current I(t), flowing responsive to the applied field, is measured by the control unit, as described hereinabove. Calculations of the values of ∫I(t)dt, dI/dt and/or d2I/dt2 are frequently performed. Comparisons of I and/or ∫I(t)dt and/or dI/dt and/or d2I/dt2 with respective threshold values are used as indicators of micro-channel formation and/or to determine when to generate the shutoff signal for the electrodes.
Further alternatively or additionally, in embodiments in which V(t) is sinusoidal, the control unit preferably calculates changes in a phase shift between V(t) and I(t) during application of the electric field, and controls the field responsive to these changes. It is believed that cells in the stratum corneum demonstrate capacitance, which causes the phase shift, and that ablation of the stratum corneum decreases the capacitance and is evidenced by a decrease in the phase shift.
Still further alternatively or additionally, the total charge which is passed through the skin is limited by a capacitor, inductor, or other energy-storage device. An appropriate choice of values for these components sets an absolute maximum quantity of charge which can pass through the skin, and thus limits any damage that can be caused thereby.
In some preferred embodiments of the present invention, one or more of the electrodes comprise or are coupled to an electrically conductive dissolving element, where the dissolving rate is generally proportional to the current passing through the electrode. When a sufficient quantity of charge has passed through the dissolving element, the electrode ceases to conduct electricity. Thus, a maximum total charge, Qtotal, is associated with an electrode, such that current flows through the element for only as long as q(t)=∫I(t)dt less than Qtotal. This serves as a safety feature, reducing the possibility of skin burns secondary to applied electric fields. Alternatively or additionally, the dissolving element is constructed so that it becomes non-conductive after a quantity of charge has passed therethrough which is sufficient to ablate the stratum corneum.
In some further preferred embodiments of the present invention, the electrodes are xe2x80x9cprintedxe2x80x9d directly on the skin, preferably by stamping or by employing a transfer patch of a conductive substance (such as, for example, a conductive ink containing silver grains). In applications of such embodiments of the present invention for transdermal drug delivery, the conductive substance preferably comprises a matrix holding the drug to be administered to a subject.
Preferably, the printed electrodes demonstrate a substantially complete loss of conductance therethrough upon ablation of the stratum corneum responsive to the applied electric field. Further preferably, each printed electrode comprises a material which is conductive only when current flowing therethrough remains below a threshold value. If the current exceeds the threshold, then thermal fusion of the material causes it to become largely nonconductive, i.e. the material acts as a fuse. Still further preferably, current continues to flow through the other electrodes until they reach the threshold current, at a time which is generally associated with the time required for ablation of the stratum corneum, as described hereinabove. In some of these embodiments, the control unit may be made substantially simpler than as described regarding other embodiments, and generally does not need other circuitry in order to determine whether to generate a shut-off signal.
In still further preferred embodiments of the present invention, two electrodes on the patch form a concentric electrode pair, in which an inner electrode generates a current which passes through the stratum corneum to an outer electrode surrounding the inner electrode. The distance between the inner and outer electrodes is preferably between about 50 and about 200 microns, in order to maintain the ratio of the lateral to the perpendicular component of the current at a high value, as described hereinabove.
In some preferred embodiments of the present invention, a conductance-enhancing substance, preferably comprising a conductive cream or ink, is applied to the skin in order to increase the ratio of the lateral to the perpendicular component of current flow. Alternatively or additionally, the conductance-enhancing substance comprises a composition with a high diffusion coefficient, which diffuses into the lipid layers of the stratum corneum and further augments the selective power dissipation therein, in order to ablate the stratum corneum with substantially little damage to the underlying tissue. In some applications, the substance has an electrical charge associated therewith, such that when a small lateral field is applied, lateral diffusion of the substance within the stratum corneum is enhanced (i.e., iontophoresis of the substance).
In some of these preferred embodiments which utilize a conductance-enhancing substance, the substance further comprises an active substance, for example, a pharmaceutical product, dissolved or mixed therein. Since breakdown of the stratum corneum is often associated with removal of the enhanced conductivity path afforded by the conductance-enhancing substance, it is preferable in many of these embodiments to use a substantially constant voltage source to generate current at the electrodes. Removal of the enhanced conductivity path will result in a desired reduced power dissipation in the stratum corneum (P=V2/R), since the voltage remains constant while resistance increases.
In other preferred embodiments of the present invention, ablation of the stratum corneum is accomplished using a current-limited source to power the electrodes. It is believed that the stratum corneum generally displays high electrical resistance, while epidermal tissue underlying the stratum corneum has significantly lower electrical resistance. Ablation of the stratum corneum (i.e., removal of the high-resistance tissue) is therefore associated with a net decrease of electrical resistance between the electrodes, and the power dissipated in the epidermis following electrical breakdown will decrease, typically proportional to the change in resistance (P=I2R).
Monitoring changes in voltage, current, and/or phase for each electrode in the control unit may require, in certain implementations, a significant amount of circuitry. Therefore, in some preferred embodiments of the present invention, the control unit comprises one or more clusters of electrodes, in which monitoring and control are performed for each cluster rather than for the individual electrodes therein. The cluster is preferably over a relatively small area of skin, for example, from about 1 mm2 to about 100 mm2, in which properties of the skin are assumed to be substantially constant.
In some preferred embodiments of the present invention, the device is a stand-alone device, which enables transdermal delivery of an active substance or enhances transdermal motion of an analyte. Alternatively, the device creates micro-channels as described hereinabove and is then removed from the skin, in order to enhance the transdermal delivery of a substance into or out of a commercially-available skin patch subsequently placed on the skin. In other preferred embodiments of the present invention, the device is an add-on to commercially available transdermal drug delivery/analyte extraction devices, and serves primarily to create the micro-channels in the stratum corneum, and optionally to act as a vehicle through which the substance may pass.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a device for ablating the stratum corneum epidermidis of a subject, including:
a plurality of electrodes, which are applied to the subject""s skin at respective points; and
a power source, which applies electrical energy between two or more of the plurality of electrodes, to cause ablation of the stratum corneum primarily in an area intermediate the respective points.
Preferably, skin layers beneath the stratum corneum are substantially not ablated. In a preferred embodiment of the present invention, the ablation of the stratum corneum causes a puncturing thereof.
Preferably, the device ablates the area of the stratum corneum in order to allow a substance to pass therethrough. Further preferably, the substance includes a drug that is delivered through the skin. Alternatively, the substance includes an analyte that is extracted through the skin.
Preferably, the power source generates an electric field which causes a current to flow through the stratum corneum, and the device reduces power dissipated in the stratum corneum responsive to variation of a characteristic of the current. Further preferably, the characteristic is drawn from a list consisting of: the magnitude of the current; a time-integration of the current; a first time-derivative of the current; and a second time-derivative of the current.
Alternatively or additionally, current through one of the plurality of electrodes is reduced substantially independently of the current through another one of the plurality of electrodes.
Further alternatively or additionally, at least one of the plurality of electrodes is coupled to receive the current through a limited-conduction unit, which unit allows current below a threshold value to flow therethrough substantially unimpeded, and becomes substantially non-conductive if the current flowing therethrough exceeds a limited-conduction threshold value.
Preferably, at least one of the plurality of electrodes is coupled to an electrically-conductive dissolving element characterized by a dissolving rate generally proportional to the current passing therethrough, which becomes substantially nonconductive responsive to a function of the current. In a preferred embodiment, the function includes a time-integral of the current having passed through the dissolving element.
Preferably, the dissolving element includes:
an electrolyte solution within the element; and
a first node and a common node immersed in the electrolyte solution,
wherein current flows from the first node to the common node through the electrolyte solution, the current flow causing the common node to be consumed at a rate generally proportional to the current passing therethrough; such that the dissolving element becomes substantially nonconductive when the total charge having passed through the common node exceeds a common node threshold value.
Further preferably, the dissolving element also includes a second node, immersed in the electrolyte solution, wherein the power source generates alternating current, and wherein the device further includes:
a first diode, coupled in series between the power source and the first node, which conducts current from the power source to the first node when the alternating current is in a positive phase thereof; and
a second diode, coupled in series between the power source and the second node, which conducts current from the second node to the power source when the alternating current is in a negative phase thereof,
such that the dissolving element becomes substantially nonconductive when the total charge having passed through the common node exceeds a common node threshold value.
Alternatively, the dissolving element includes:
an electrolyte solution within the element;
a large-area anode immersed in the electrolyte solution; and
a plurality of cathodes, immersed in the electrolyte solution, each of the cathodes being coupled to a respective one of the plurality of electrodes,
wherein current flows from the large-area anode to the plurality of cathodes through the electrolyte solution, the current flow causing at least one of the cathodes to be consumed at a rate generally proportional to the current passing therethrough, and wherein the at least one cathode becomes substantially nonconductive responsive to a function of the current having passed therethrough.
Preferably, the current through at least one of the plurality of electrodes is reduced responsive to the variation of the characteristic of the current through another one of the plurality of electrodes.
In a preferred embodiment, the device also includes a voltage sensing unit coupled to measure a voltage drop across two of the plurality of electrodes, and current from the power source is reduced responsive to the measurement made by the sensing unit. Preferably, the power source includes a current source, and current from the current source is reduced responsive to a measurement made by the sensing unit which indicates that the electrical potential between the two electrodes is below a voltage-threshold value.
Alternatively or additionally, the device includes a resistive element coupled to one of the two electrodes and to the power source, and the voltage sensing unit is further coupled to measure a voltage drop across the resistive element in order to determine a current passing therethrough. The power source includes an alternating current source, such that the measurements of the voltage drop across the two electrodes and the current through the resistive element determine a phase shift. The current from the alternating current source is reduced responsive to the phase shift being below a threshold value.
In a preferred embodiment, the device includes:
a resistive element coupled to one of the plurality of electrodes and to the power source; and
a voltage sensing unit coupled to measure a voltage drop across the resistive element in order to determine a current passing therethrough.
In this preferred embodiment, the power source includes a voltage source, and the voltage is reduced responsive to a measurement made by the sensing unit which indicates that the current through the resistive element is above a current-threshold value.
In another preferred embodiment, at least one of the plurality of electrodes is printed directly on the skin and becomes substantially electrically nonconductive responsive to the value of the current passing therethrough being greater than a threshold value.
In yet another preferred embodiment, the device includes:
a capacitor, coupled to two of the plurality of electrodes; and
a switch, coupled to the power source and the capacitor, such that the switch, in a closed phase thereof, allows current to flow from the power source to the capacitor and to the two electrodes, and such that the switch, in an open phase thereof, substantially terminates current flow from the power source to the capacitor and to the two electrodes.
In this embodiment, the power source charges the capacitor during the closed phase, and the capacitor discharges current through the electrodes during the open phase.
Preferably, the distance between two of the plurality of electrodes is less than about 0.3 mm. Further preferably, the distance between two of the plurality of electrodes is between about 0.01 mm and about 0.1 mm.
Preferably, the plurality of electrodes include:
a common electrode, which has a plurality of perforations therethrough; and
a plurality of positive electrodes, each positive electrode passing through a respective perforation of the common electrode,
such that current from the power source flows from each positive electrode through the skin to the common electrode.
In a preferred embodiment, the power source generates alternating current, a frequency thereof being above about 100 Hz. Preferably, the frequency is between about 1 kHz and about 300 kHz. Alternatively or additionally, the power source modulates a frequency of the alternating current between a first frequency value and a second frequency value.
There is further provided, in accordance with a preferred embodiment of the present invention, a device for passing electrical current through the skin of a subject, including:
a power source, which generates the current;
a plurality of electrodes, which are applied to the skin at respective points; and
an electrically conductive dissolving element coupled to at least one of the electrodes, the element being characterized by a dissolving rate generally proportional to the current passing therethrough, and becoming substantially nonconductive responsive to a function of the current passing therethrough.
There is also provided, in accordance with a preferred embodiment of the present invention, a method for ablating the stratum corneum epidermidis of a subject, including:
placing a plurality of electrodes against the subject""s skin at respective points; and
applying electrical energy between two or more of the plurality of electrodes, in order to cause ablation of the stratum corneum primarily in an area intermediate the respective points.
Preferably, skin layers beneath the stratum corneum are substantially not ablated. In a preferred embodiment, applying the electrical energy includes puncturing the skin.
Preferably, applying the energy includes ablating the area of the stratum corneum in order to allow a substance to pass through the area. Further preferably, the method includes delivering a drug or extracting an analyte through the area.
Preferably, applying electrical energy includes:
causing a current to flow through the points on the skin; and
substantially reducing the current flow through the skin responsive to variation of a characteristic of the current.
In a preferred embodiment, the characteristic is drawn from a list consisting of: a magnitude of the current; a time-integration of the current; a first time-derivative of the current; and a second time-derivative of the current.
In another preferred embodiment, causing the current to flow includes passing current to the one or more points on the skin through one or more respective limited-conduction units, wherein the units allow current below a threshold value to flow therethrough substantially unimpeded, and wherein the units become substantially nonconductive if the current flowing therethrough exceeds a limited-conduction threshold value.
In another preferred embodiment, causing the current to flow includes passing current to the one or more points on the skin through one or more respective electrically conductive dissolving elements, each element characterized by a dissolving rate generally proportional to the current passing therethrough, and each element becoming substantially nonconductive when the total charge having passed therethrough exceeds a dissolving element threshold value.
In yet another preferred embodiment, reducing the current flow includes reducing the current at one of the respective points substantially independently of the current at another one of the respective points.
In still another preferred embodiment, reducing current flow includes:
monitoring the current flow through one of the plurality of electrodes; and
reducing the current flow through another one of the plurality of electrodes responsive thereto.
Preferably, placing the plurality of electrodes includes placing two of the plurality of electrodes at a separation therebetween that is less than about 0.3 mm. Further preferably, placing the plurality of electrodes includes placing the two of the plurality of electrodes at a separation between about 0.01 mm and about 0.1 mm.
In a preferred embodiment, placing the plurality of electrodes includes:
applying a conduction-enhancing material to an area on the surface of the subject""s skin in order to enhance current flow through the skin; and
placing the electrodes on the material,
wherein the electrical resistance of the conduction-enhancing material increases responsive to a function of the current flow therethrough.
Preferably, placing the plurality of electrodes includes:
placing on the skin a common electrode which has a plurality of perforations therethrough; and
placing on the skin a plurality of positive electrodes, each positive electrode passing through a respective perforation in the common electrode, such that current from the power source flows from each positive electrode through the skin to the common electrode.
Further preferably, the method includes positioning in a vicinity of the electrodes a medical patch containing the substance, such that ablation of the stratum corneum increases a transport rate of the substance from the patch into the skin.
In a preferred embodiment, applying electrical energy includes generating alternating current, a frequency thereof being above about 100 Hz. Preferably, the frequency is between about 1 kHz and about 300 kHz. Alternatively or additionally, applying electrical energy includes modulating a frequency of the alternating current between a first frequency value and a second frequency value.
There is additionally provided, in accordance with a preferred embodiment of the present invention, a method for passing electrical current through the skin of a subject, including:
placing a plurality of electrodes against the skin at respective points; applying the current through the electrodes; and
coupling to at least one of the electrodes an electrically conductive dissolving element, the element being characterized by having a dissolving rate generally proportional to the current passing therethrough, and by becoming substantially nonconductive responsive to a function of the current passing therethrough.
The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which:
FIG. 1A is a schematic, partly sectional illustration of a device for transdermal transport of a substance, in accordance with a preferred embodiment of the present invention;
FIG. 1B is a schematic, partly sectional illustration of another device for transdermal transport of a substance, in accordance with a preferred embodiment of the present invention;
FIG. 2 is a schematic bottom view of the device of FIG. 1A, in accordance with a preferred embodiment of the present invention;
FIG. 3 is a schematic illustration of a switching unit in the device of FIG. 1A, in accordance with a preferred embodiment of the present invention;
FIG. 4 is a schematic illustration of an electrode assembly, in accordance with a preferred embodiment of the present invention;
FIG. 5 is a schematic illustration of another electrode assembly, in accordance with a preferred embodiment of the present invention;
FIG. 6 is a schematic illustration of yet another electrode assembly, in accordance with a preferred embodiment of the present invention;
FIG. 7 is a schematic illustration of still another electrode assembly, in accordance with a preferred embodiment of the present invention;
FIGS. 8A and 8B are schematic illustrations of charge-limited electrode assemblies, in accordance with preferred embodiments of the present invention;
FIG. 9 is a schematic illustration of another charge-limited electrode assembly, in accordance with a preferred embodiment of the present invention;
FIG. 10 is a schematic illustration of yet another charge-limited electrode assembly, in accordance with a preferred embodiment of the present invention;
FIG. 11A is a schematic side view of a concentric electrode assembly, in accordance with a preferred embodiment of the present invention; and
FIG. 11B is a schematic top view of a common electrode layer in the concentric electrode assembly of FIG. 11A, in accordance with a preferred embodiment of the present invention. | {
"pile_set_name": "USPTO Backgrounds"
} |
The present invention relates generally to the field of aircraft rotors, and in particular to a rotor design for use in a helicopter or similar aircraft.
Helicopters generally incorporate at least two rotors into their design. The large rotor providing thrust in the vertical direction is known as the main rotor. In addition to this main rotor, the traditional helicopter design incorporates a tail rotor system to counteract the torque from the main rotor system. Although operable helicopter designs have been produced without the traditional tail rotor geometry, the vast majority of helicopters use this design. The number of blades in the tail rotor itself will depend on the requirements of a particular application.
A significant limitation inherent in the design of prior multi-bladed tail rotors is their inability to satisfactorily accommodate potentially powerful Coriolis torque. A Coriolis torque is generated in a helicopter rotor whenever the rotor plane is tilted relative to the shaft. Since the 1/rev Coriolis torque is proportional to the coning angle, it is usually negligible for most tail rotors. For a two-bladed tail rotor, the 2/rev Coriolis torque is also not a problem because both blades speed up and slow down at the same time, and the drive system is generally sufficiently flexible to provide the necessary torsional freedom. The 2/rev Coriolis torque does, however, become a problem with a multi-bladed rotor if insufficient lead-lag articulation is provided.
Existing multi-bladed tail rotors use a variety of methods to provide the necessary relief for 2/rev Coriolis torque. One design, developed by Sikorsky, uses a fully articulated rotor, complete with lead-lag hinges and dampers. Another design incorporates a flexible spindle at the blade root combined with restricted flapping motion to limit stresses due to Coriolis torque. One design, used by Kaman, allows a small amount of lead-lag motion by using a xe2x80x9crocking pinxe2x80x9d arrangement in its flapping hinge. Yet another design, developed by Lockheed, uses a gimbaled tail rotor hub that relieves the 2/rev Coriolis torque in the same manner as a two-bladed teetering rotor.
All of these designs suffer from limitations. In general, each of the above solutions is heavy and complex. Each requires the use of heavily-loaded bearings oscillating at tail rotor frequency, resulting in designs requiring high levels of maintenance and excessive downtime.
Accordingly, there is a need in the art for a tail rotor assembly overcoming the above-described limitations of the prior art designs, including reduction of tail rotor weight and mechanical complexity, reduction or elimination of catastrophic failure modes, and increased service life of the tail rotor mechanisms.
The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention, and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
The present invention relates to a dual-trunnion hub-to-mast assembly that provides improved damage tolerance with extended life expectancy and reduced maintenance burden due to the use of composite and elastomeric materials. In certain embodiments, the assembly is useful as part of a tail rotor assembly consisting of two stacked two-bladed teetering rotors, mounted on a single output shaft.
The present invention makes use of a variety of novel features to overcome the inherent limitations of the prior art. In certain embodiments, the present invention achieves increased-service life of the tail rotor mechanisms. In certain embodiments, the present invention achieves a reduction or elimination of catastrophic failure modes by the incorporation of redundant load paths within the rotor structure. In certain embodiments, the tail rotor of the present invention may be employed in a xe2x80x9cpusherxe2x80x9d implementation for improved aerodynamic performance by minimizing vertical fin blockage effects.
In addition to the above advantages, in certain embodiments the teachings of the present invention may provide improved aerodynamic efficiency, higher maneuvering capability, improved mechanical flaw tolerance design, and extended life expectancy. In certain embodiments, the present invention allows for reduced maintenance due to the use of composites and elastomerics. In one embodiment, a tail rotor constructed according to the present invention has been designed to achieve a minimum life of 10,000 hours of severe duty use in ground-air-ground maneuvers, air combat maneuvers, and high cycle vibratory loads, with little or no maintenance.
In certain embodiments, the present invention makes extensive use of multiple primary load paths in order to provide a fail-safe structure. In certain embodiments, the present invention provides redundant load paths for critical metal parts to minimize catastrophic failure modes. Certain embodiments eliminate the use of the bearings traditionally required to carry the full centrifugal force of the blade while oscillating at tail rotor one-per-revolution. This is done in order to further increase life expectancy, improve reliability, and minimize maintenance. In certain embodiments, the present invention minimizes control washout to the blades due to control system softness.
As described above, a significant limitation inherent in the design of prior multi-bladed tail rotors is their inability to satisfactorily accommodate potentially powerful Coriolis torque. A Coriolis torque is generated in a helicopter rotor whenever the rotor plane is tilted relative to the shaft. Since the 1/rev Coriolis torque is proportional to the coning angle, it is usually negligible for most tail rotors. For a two-bladed tail rotor, the 2/rev Coriolis torque is also not a problem because both blades speed up and slow down at the same time, and the drive system is generally sufficiently flexible to provide the necessary torsional freedom. The 2/rev Coriolis torque does, however, become a problem with a multi-bladed rotor if insufficient lead-lag articulation is provided.
Existing multi-bladed tail rotors use a variety of methods to provide the necessary relief for 2/rev Coriolis torque. One design, developed by Sikorsky, uses a fully articulated rotor, complete with lead-lag hinges and dampers. Another design incorporates a flexible spindle at the blade root combined with restricted flapping motion to limit stresses due to Coriolis torque. Another design, used by Kaman, allows a small amount of lead-lag motion by using a xe2x80x9crocking pinxe2x80x9d arrangement in its flapping hinge. Yet another design, developed by Lockheed, uses a gimbaled tail rotor hub that relieves the 2/rev Coriolis torque in the same manner as a two-bladed teetering rotor.
All of these designs suffer from inherent limitations. In general, each of the above solutions is heavy and complex. Each requires the use of highly-loaded bearings oscillating at tail rotor frequency, resulting in designs requiring high levels of maintenance and excessive downtime.
One manner of addressing this problem is to mount a pair of two-bladed rotors on the same shaft. This arrangement provides a four-bladed tail rotor with the mechanical and structural simplicity of a two-bladed teetering rotor. By using this concept, no bearings are required to oscillate while carrying the full centrifugal force of the blade.
Although this solution partially addresses the above-described problems, it does not inherently provide relief for the 2/rev Coriolis torque. With this design, whenever the tail rotor experiences first harmonic flapping, one pair of blades will be attempting to accelerate at the same instant in time that the other pair of blades is attempting to decelerate. Thus, the two rotors will try to move in the same manner as a pair of scissors, placing considerable stress on the rotor hub components.
In spite of these limitations, variations on this approach have been employed successfully in aircraft. One design uses a double-teetering tail-rotor with coaxial shafts. Aircraft using this design have been successfully flown. Another design uses a double-teetering tail rotor with flexible forks. While both these approaches provide the desired relief for 2/rev Coriolis torque, there are several disadvantages associated with each one. The designs exhibit increased mechanical complexity and a heavier design. In addition, there are problems associated with tailoring the stiffness of critical metal parts, possibly resulting in a degraded structural design and potentially catastrophic failure modes.
The tail rotor of the present invention utilizes a modification of the above approach. In one embodiment of the present invention, each of a pair of two-bladed rotor assemblies is independently mounted on a common drive shaft. Each rotor assembly is a two-bladed teetering rotor. The spanwise axis of the blade-pair units are perpendicular to each other, and are separated axially to provide adequate space for accommodating hub attachment hardware and operational clearance between them.
The 2/rev Coriolis relief for the tail rotor system of the present invention is provided by optimizing the dynamic charactericstics of an existing component in the system rather than by adding additional hardware. The rotor assembly uses an elastomeric bearing to accommodate rotor flapping. Conventional teetering rotors that use elastomeric bearings to provide flapping degree of freedom require the radial stiffness of the bearings to be very high in order to minimize radial deflection under rotor torque. In the design of the present invention, however, the bearing radial stiffness is tailored to provide adequate stiffness to react rotor torque and to provide adequate softness to relieve for 2/rev Coriolis loads. Since the Coriolis relief is provided by tailoring the spring rate of an existing component required to accommodate the xe2x80x9cflappingxe2x80x9d degree of freedom anyway, the resulting hub assembly provides a much simpler configuration with reduced weight and cost, and higher reliability due to reduction in number of parts.
In one embodiment of the present invention, an inboard trunnion and outboard trunnion are clamped together on a tail rotor mast using a pair of tapered cones, a hub adapter, and a mast nut. The tail rotor mast transmits drive torque to the inboard trunnion by means of a spline section. The inboard trunnion has mating splines on its inside surface to mate with the mast spline section, and curvic teeth on its outboard face to mate with the corresponding teeth on the hub adapter.
A cone set between the inboard trunnion and inboard shoulder of the mast provides positive centering of the inboard trunnion and locks out radial looseness in the spline section. The drive torque is transmitted to the outboard trunnion from the inboard trunnion through a hub adapter having an inboard curvic coupling mating with the inboard trunnion and an outboard curvic coupling mating with the outboard trunnion. A second cone set between the outboard trunnion and the mast nut provides centering of the outboard trunnion.
In certain embodiments, the section of the mast outboard of the inboard trunnion has a reduced outside diameter to produce a torsional stiffness significantly lower than the torsional stiffness of the hub adapter. Thus for any rotational deflection of the outboard trunnion, the mast will rotate an equivalent amount with this rotation occurring in the reduced section of the mast and not at the outboard cone set joint.
In certain embodiments, the cones, trunnions, and hub adapter slide over the tail rotor mast and are sandwiched between an integral shoulder of the mast and the mast nut. The mast nut torque produces an axial pre-load across these components. The axial pre-load generates the desirable frictional clamp up at the outboard cone and counteracts separation force from the curvic coupling joints.
The primary purpose of the hub adapter is to deliver drive torque to the outboard trunnion. The inboard trunnion is splined to the mast. Accordingly, all of the steady drive torque from the mast goes into the inboard trunnion. Approximately half of that torque goes into the inboard rotor through the inboard yoke. The remaining drive torque exits the inboard trunnion, goes through the hub adapter, and into the outboard trunnion, which drives the outboard yoke and outboard blades. It will be noted that the outboard trunnion is not splined to the mast. Therefore the hub adapter sees about one half of the mast torque as a steady load.
The above-described structure provides a number of benefits, including reduced failure due to fretting and wear, the absence of relative motion at the attachment joints, and commonality between the inboard and outboard rotor assemblies. Since the 2/rev Coriolis torque loads between the inboard trunnion and outboard trunnion are reacted by the curvic couplings, and not the tail rotor mast spline section, the potential failure due to fretting is reduced. Since the two stacked rotor trunnions are clamped together through curvic couplings, they are securely fixed to one another via a tight joint, which is desirable for minimizing the fretting and wear common to joints that see high oscillatory loads. The torsionally-soft outboard section of the mast accommodates the angular deflection between the two trunnions with minimal relative motion occurring at the attachment joint surfaces. Finally, this design allows for common inboard and outboard rotor assemblies, which can be assembled, replaced and shipped as individual 2-bladed assemblies.
There are at least two major design considerations in the sizing of the curvic couplings of the hub adapter. First, each of the couplings must be capable of reacting the steady, oscillatory, and limit torque loads imposed by the tail rotor. Second, it is desirable that the axial pre-load across the couplings be high enough to prevent joint separation during operation. The couplings and surrounding hardware (cone sets, mast nut, and mast) must also be capable of carrying the pre-load requirement. The size and pitch of the curvic couplings will, of course, vary from one application to another.
The novel features of the present invention will become apparent to those of skill in the art upon examination of the following detailed description of the invention. It should be understood, however, that the detailed description of the invention and the specific examples presented, while indicating certain embodiments of the present invention, are provided for illustration purposes only because various changes and modifications within the spirit and scope of the invention will become apparent to those of skill in the art from the detailed description of the invention and claims that follow. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates to a plasma processing method using a plasma processing apparatus. More particularly, it relates to a plasma cleaning in the plasma processing method.
In order to enhance the productivity of semiconductor devices in the semiconductor processing field, it is requested that, in the plasma etching, the dropping of microscopic particles onto a microminiaturized structure fabricated on a wafer is reduced to the minimum possible degree. The mechanisms of the emission of the particles are explained as follows. Deposition film formed during wafer processing on the inner-wall surface of a processing chamber and on parts inside the chamber is re-injected onto the wafer. Or the material itself constituting the surface of the inner-wall and the parts is emitted and dropped onto the surface of the wafer. In view of this situation, as measures for reducing the emission of the microscopic particles, the following method or configuration is devised and used. Namely, a plasma cleaning method for removing the deposited film can be used. Otherwise, a material which can prevent the emission of the microscopic particles is used as the inner-wall surface and the inside parts of a processing chamber.
As the conventional technology for reducing the emission of the microscopic particles, there exists the method of applying the plasma cleaning to the deposited film after the wafer processing. In JP-A-10-261623, the emission of the microscopic particles is reduced as follows. Namely, in addition to the conventional plasma-cleaning-based method of removing deposited films, the emission of the microscopic particles is reduced by using a plasma which is capable of chemically decomposing and removing a chemical compound formed between the inner-wall material released into the processing chamber and a processing gas used. Also, in JP-A-10-233388, the emission of the microscopic particles is reduced as follows. Namely, after the deposited-film removing step is over, the emission of the microscopic particles is reduced by adding a step that releases the reaction product of residual adsorbed gases from the inner-wall surface into the processing chamber. Here, this releasing operation is performed by exposing the inner-wall surface to plasma for a short time of a few hundreds of milliseconds to a few seconds.
In mass production of the devices, the amount of deposit material or the chemical compound which is formed from the processing chamber's inner-wall material and the processing gas is increased with increasing the time of the continuous processing of wafers. As a result, the number of the microscopic particles is increased. In order to address this problem, the apparatus is disassembled, and the washing or replacing operation for the processing chamber's inner-wall parts is carried out. In order to restart wafer processing after these operations, however, the start-up of the processing chamber takes a few hours to about a day. In addition, the start up time decreases the productivity of the devices. Accordingly, it is requested to provide a plasma processing apparatus or plasma-processing operating method which makes it possible to continue the plasma processing over a longer time in a state where the number of the microscopic particles is small.
On the surface of the wafer, there exist an area where the microminiaturized structure is fabricated with high density and an area of that with low density. When the microscopic particles drop onto the area of the low density of the structure, the dropped microscopic particles exert only a little influence on a decrease in the yield of the device. This situation holds as long as the microscopic particles are sufficiently smaller as compared with the structure. Meanwhile, when the microscopic particles drop onto the area of the high density of the structure, it becomes highly possible that the yield decreases with the worsening of the etching profile under the dropped particles. Also, the worsened area is enlarged in proportion to the size of the particles and the yield decreases. Consequently, with the development of microminiaturization in a semiconductor processing in recent years, it is requested that the number of the microscopic particles which will drop onto a wafer and the diameter of the particles are decreased as small as possible.
As described above, one of the causes for the emission of the microscopic particles is as follows. Namely, the processing chamber's inner-wall material is sputtered by the plasma used. Then, the sputtered inner-wall material is released into the processing chamber as the microscopic particles. Accordingly, it is preferable that a material which has tremendously high resistance to the plasma sputtering is employed as the processing chamber's inner-wall material. In view of this situation, in recent years, there has been more employment of the following new plasma-resistant materials: a sprayed-on product or sintered body of yttria (which, hereinafter, will be referred to as “Y2O3”), and Y2O3 or alumina (Al2O3) to which a trace amount of various elements such as zirconia is added for the purpose of enhancing the plasma-resistant property. | {
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Business intelligence (BI) is a business management term that refers to applications and technologies that are used to gather, provide access to, and analyze data and information about business operations. Business intelligence systems can help companies have a more comprehensive knowledge of the factors affecting their business, such as metrics on sales, production, internal operations, and they can help companies make better business decisions.
Business intelligence applications and technologies can enable organizations to make more informed business decisions, and they may give a company a competitive advantage. For example, a company could use business intelligence applications or technologies to extrapolate information from indicators in the external environment and forecast the future trends in their sector. Business intelligence is used to improve the timeliness and quality of information and enable managers to better understand the position of their company in comparison to its competitors.
Business intelligence applications and technologies can help companies analyze the following: changing trends in market share, changes in customer behavior and spending patterns, customers' preferences, company capabilities and market conditions. Business intelligence can be used to help analysts and managers determine which adjustments are most likely to affect trends. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
An apparatus consistent with the present invention relates to a microwave oven and, more particularly, to a microwave oven provided with a cooking container for both steaming and grilling food.
2. Description of the Related Art
Microwave ovens are used to cook or heat food located in a cooking compartment using high-frequency waves generated from a magnetron installed in an electric element compartment. Generally, in such a microwave oven, high-frequency waves irradiate the cooking compartment so as to repeatedly alter the molecular arrangement of water contained in food; thus, cooking the food by means of frictional heat generated between molecules of the water.
In order to cook food evenly in the cooking compartment, a rotating turntable for mounting food thereon or a stirrer for dispersing high-frequency waves is installed in the cooking compartment.
Various types of cooking containers can be positioned in the cooking compartment of the microwave oven so as to cook food by various methods using high-frequency waves that irradiate the cooking compartment.
For example, cooking containers that are specifically designed for steaming and grilling may be used. When food is required to be steamed, a container designed for steaming is irradiated with the high-frequency waves. Similarly, a container designed for grilling food is irradiated when grilled food is desired.
Since the conventional cooking containers used in the conventional microwave oven are designed for either steaming or grilling food, the microwave oven must include both a cooking container for steaming and a cooking container for grilling in order to perform both steaming and grilling functions.
Accordingly, the conventional microwave oven includes separate cooking containers for steaming and grilling. Thus, there is an increased cost of ownership since both cooking containers are needed, and more storage space is required for storing both the cooking containers. | {
"pile_set_name": "USPTO Backgrounds"
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Headrest support assemblies are common in vehicles. However, as currently designed, the headrest support assemblies require multiple anchors and pieces to adequately distribute loading of the headrest. Accordingly, a headrest support assembly is provided herein have a single-piece support received by the headrest bun and the seatback. | {
"pile_set_name": "USPTO Backgrounds"
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Field of the Invention
The present invention relates to a method and apparatus for positioning a head at a position on a predetermined reference track of a disk medium in response to a rezero request, etc. in a disk storage unit. | {
"pile_set_name": "USPTO Backgrounds"
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As the use of digital data increases, the demand for faster, smaller, and more efficient memory structures used for storing that digital data increases. One type of memory structure which has recently been developed is a crossbar memory structure. A crossbar memory structure includes a set of upper parallel wires which intersect a set of lower parallel wires. A programmable memory element is placed at the intersections between the upper and lower parallel lines. The programmable memory element may store digital data.
One type of programmable memory element which may be used is a memristive element. A memristive element is a device which changes the state of its resistance based on an applied programming condition. For example, a programming condition may be applied to change the memristive element from a high resistive state to a low resistive state or vice versa. A high resistive state may represent a digital “1” and a low resistive state may represent a digital “0”.
One challenge that results from use of a crossbar memory structure is the process of reading the state of a specific memory element. The state of a memory element may be determined by applying a sensing condition such as a sense voltage or a sense electric current. The behavior of the sensing condition when applied to a memory element may be indicative of the current state of that memory element. However, when applying sensing conditions in such a manner, the sensing condition will be adversely affected by other memory elements along the upper wire and along the lower wire to which the memory element to be read is connected. Thus, it is difficult to isolate the memory element to be read from other memory elements within the crossbar array for the purpose of reading the state of the memory element.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. | {
"pile_set_name": "USPTO Backgrounds"
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It is highly desirable for tires to have good wet skid resistance, low rolling resistance, and good wear characteristics. It has traditionally been very difficult to improve a tire's wear characteristics without sacrificing its wet skid resistance and traction characteristics. These properties depend, to a great extent, on the dynamic viscoelastic properties of the rubbers utilized in making the tire.
In order to reduce the rolling resistance and to improve the treadwear characteristics of tires, rubbers having a low hysteresis have traditionally been utilized in making tire tread rubber compounds. On the other hand, in order to increase the wet skid resistance of a tire, rubbers which undergo a large energy loss have generally been utilized in the tire's tread. In order to balance these two viscoelastically inconsistent properties, mixtures of various types of synthetic and natural rubber are normally utilized in tire treads. For instance, various mixtures of styrene-butadiene rubber and polybutadiene rubber are commonly used as a rubbery material for automobile tire treads. However, improvements in rolling resistance often occur in tandem with a reduction in wet traction, and vice versa. There is a continuing need, therefore, to develop tread having both good rolling resistance and wet traction. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to methods for manufacturing non-oriented magnetic steel sheets having superior magnetic properties. Such sheets are ideally suitable as magnetic components for rotating elements such as electric motor cores and the like.
In particular, this invention relates to methods for manufacturing semiprocessed non-oriented magnetic steel sheets having superior workability in assembling iron cores for motors and the like, and having superior magnetic properties after stress relief annealing following assembly.
As referred to herein, a xe2x80x9csemiprocessedxe2x80x9d magnetic steel sheet is a substantially non-oriented magnetic steel sheet which exhibits superior magnetic properties after stress relief annealing. Usually, stress relief annealing is performed at 700 to 800xc2x0 C. for approximately 2 hours following the step of die cutting the sheet by customers. In general, the non-oriented steel sheet is manufactured by pickling hot-rolled steel sheets with or without annealing thereof, and cold rolling, annealing and skin pass rolling the sheet.
2. Description of the Related Art
Magnetic sheet steel materials for rotating motor or generator cores or the like are magnetized in various directions substantially parallel to the surfaces of the materials. Such materials have substantially no magnetic anisotropy and are accordingly very advantageous for use in rotating electrical components and the like.
A method is disclosed in Japanese Examined Patent Application Publication No. Hei-7-59725 in which hot rolling conditions are controlled, and a method is disclosed in Japanese Unexamined Patent Application Publication No. Hei-3-75313 in which annealing is performed for hot-rolled steel sheets.
In addition, recently, in order to alleviate the effect of magnetic anisotropy of the steel sheets after performance of die cutting operations for cores for motors, manufacturing methods for making iron cores have been somewhat improved. For example, a so-called xe2x80x9crotation pilingxe2x80x9d method can be performed, in which, when a set of a predetermined number of cores is piled, a following set of cores is piled at or along one or more different angles therefrom, by rotating. As a result, differences in performances of motor cores caused by anisotropy of materials are not very significantly manifested, compared to those conventionally observed.
Recently, the processes of assembling motor cores have been significantly automated. As a result, in particular, improvements of material thickness accuracy and of die cutting properties have been strongly desired.
Concerning improvements of material thickness accuracy and of die cutting properties, some methods have been proposed; for example, Japanese Examined Patent Application Publication No. Hei-4-25345 disclosed a method in which grain diameters of a steel sheet are controlled before skin pass rolling, Japanese Unexamined Patent Application Publication No. Hei-9-35925 disclosed a method in which an appropriate amount of titanium (Ti) is added, and Japanese Unexamined Patent Application Publication No. Hei-10-25552 disclosed a method in which material elongation percentage is controlled. However, since the methods mentioned above are proposed from experimental results based on the observed phenomena, the reasons for the proposals are not sufficiently explained, and in addition, any effects achieved are not sufficient for practical commercial use.
An object of the present invention is to provide a manufacturing method which can be advantageously applied to the manufacture of semiprocessed magnetic steel sheets, in which productivity increase and higher accuracy of product thickness can be realized by improving workability of a die cutting step without impairing the magnetic properties of the sheet. Improvements of workability in a die cutting step can be achieved by, for example, reducing flash height and reducing material thickness variation.
According to the present invention, the method for manufacturing a semiprocessed non-oriented magnetic steel sheet having superior workability and magnetic properties after stress relief annealing, comprises hot rolling a steel slab containing about 0.001 to 0.03 wt % carbon (C), about 0.1 to 1.0 wt % silicon (Si), about 0.01 to 1.0 wt % aluminum (Al), about 0.05 to 1.0 wt % manganese (Mn), and about 0.001 to 0.15 wt % phosphorus (P), cold rolling the hot rolled sheet, continuously annealing the cold rolled sheet and skin pass rolling the annealed sheet, wherein the average rapid cooling rate of continuous annealing is about 10xc2x0 C./second or more, and wherein skin pass rolling is performed at a reduction rate of about 0.5 to 5% within about 20 hours after the rapid cooling is completed. In addition, in the method of the present invention, rapid cooling in the continuous annealing step is preferably performed at a rate of about 10xc2x0 C./second or more between about 600 to 400xc2x0 C. Furthermore, the steel slab preferably further comprises at least one of about 0.001 to 0.20 wt % tin (Sn), about 0.001 to 0.10 wt % antimony (Sb), and about 0.001 to 0.010 wt % boron (B), and the difference between the amount of carbon present in the steel slab and the Ceq obtained by the equation (1) shown below is preferably about 0.001 wt % or more, in which the Ceq value is calculated from the wt % amounts of the impurities titanium (Ti), niobium (Nb), vanadium (V), and zirconium (Zr) in the steel slab. The equation is:
Ceq(wt %)=12xc3x97{[Ti(wt %)]/48+[Nb(wt %)]/93+[V(wt %)]/51+[Zr(wt %)]/92}xe2x80x83xe2x80x83(1) | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates generally to envelopes, and more specifically to envelopes of the type that are adapted to be used for transactions using banking machines.
The use of an envelope type carrier for transporting money between a cashier and a customer at locations such as drive-in windows has been in existence for years. These carriers generally include a sheet of paper that is folded to produce a carrier that is open at one side and along one end.
Quite recently, the banking industry has developed computerized automatic banking centers that may be positioned at remote locations and need not have an operator or a teller present for the customer to transact business.
Manufacturers of carriers for use in banks and particularly remote banking centers, are constantly striving for producing a simplified version of carrier for envelopes while still insuring that the envelope can be readily sealed sufficiently so that the contents does not get separated from the envelope. | {
"pile_set_name": "USPTO Backgrounds"
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A customer self-help system is a system that supports or accompanies one or more other software systems by helping users of the one or more other software systems find answers to their questions, without involving live customer support personnel. If a customer self-help system adequately helps a user find a satisfactory answer to the user's question, the user is less likely to seek addition support from live customer support (e.g., telephone support, live chat, text message, etc.). A business benefit of a well-functioning customer self-help system is reduced overhead costs for a company because providing live customer support can be expensive (e.g., sometimes costing as much as $25 per use of the live customer support). A user benefit of a well-functioning customer self-help system is that users can find answers to their questions more quickly than having to wait for live customer support because use of live customer support usually involves waiting in a queue for a turn to communicate with a customer support representative.
Traditional customer self-help systems use content searching methods that employ content prioritization techniques. In some cases, these prior art prioritization techniques inadequately match available customer support content with user search queries. In particular, traditional customer self-help systems prioritize the relevance of customer support content based on the creation date (e.g., file creation date) of the customer support content. Consequently, newer customer support content (e.g., user experience pages) are prioritized over older customer support content. While this approach could be used to prioritize some customer support content (e.g., product features), such an approach is less appropriate for customer support content that does not change very often (e.g., tax laws or regulations). In other words, such an approach might de-prioritize customer support content that is the most relevant to a search query because the age of the customer support content is older than newer customer support content, leading to search results that are not relevant or most relevant to a user's search query.
A problem with failing to provide users with information that is relevant or most relevant to their search query is that the customer self-help system may appear useless, e.g., be irrelevant, to the users. If a user enters a search query and does not obtain search results that are expected or that answer the user's question, then the user may continue to feel concerned about one or more aspects of the financial management system that led the user to submitting a search query in the first place. A natural result is that the user will lose trust in the customer self-help system and possibly in any financial management systems associated with the customer self-help system.
Another problem with failing to provide users with information that is relevant or most relevant to their search query is that the customer self-help system may fail to capitalize on becoming a trusted source of information for users. For example, if a media outlet (e.g., AARP®, CNN®, Financial Times®, etc.) makes an announcement that is related to obtaining a particular financial advantage (e.g., based on a change to tax laws), users who search a customer self-help system for more information about the announcement may recognize the customer self-help system as a trusted source of information. However, users who receive search results that appear to be oblivious to the announcement may be disappointed and look elsewhere for guidance, both for the current situation and for future issues.
Another problem associated with failing to provide users with information that is relevant or most relevant to their search query is that the customer self-help system may be providing users with the faulty (e.g., out-dated) instructions. For example, if a customer self-help system provides a user with information on how to address a particular product error, even though the product error has been resolved, then the user is essentially being instructed to perform one or more unnecessary steps to address a problem that is no longer relevant.
Traditional content searching techniques include associating the relevance of searchable customer support content with the age of customer support content, but the age of the customer support content is not necessarily the dominant characteristic that determines whether the customer support content is relevant or highly relevant at a given point in time. Thus, a technical problem that exists for customer self-help systems and search engines is a need to avoid providing less-relevant or irrelevant search results due to poor prioritization of customer support content. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to a structure for a plunger pump which can be optimally applied for an anti-skid brake control system for an automotive vehicle, and specifically to a support structure for a plunger operably employed in a plunger pump.
2. Description of the Prior Disclosure
Recently, there have been proposed and developed various automotive brake control systems associated with at least one of advantageous braking force control systems, namely a traction control system generally abbreviated as a TCS which is provided for suppressing excessive driving force exerted on driven wheels during quick depressing operation of an automotive accelerator pedal, such as quick starting, quick acceleration, or the like, and an anti-skid brake control system generally abbreviated as an ABS which is provided for preventing brakes from locking vehicle wheels during quick braking or during braking on a low frictional road surface so as to provide maximum effective braking. Of these braking force control systems, the ABS generally includes at least one brake fluid reservoir associated with either the front-wheel side or the rear-wheel side for temporarily storing the brake fluid returned from the wheel cylinders, and an auxiliary pump unit arranged for supplying the brake fluid in the wheel cylinders to the brake fluid reservoir so as to reduce the wheel cylinder pressure during the anti-skid brake control. The ABS also includes a pressure intensifying valve and a pressure reducing valve both connected to the associated wheel cylinder. The pressure intensifying valve is provided between the outlet port of the master cylinder and the inlet port of the wheel cylinder so as to establish or block the brake fluid flow from the master cylinder to the wheel cylinder, while the pressure reducing valve is provided between the brake fluid reservoir and the wheel cylinder so as to return the brake fluid in the wheel cylinder through the brake fluid reservoir and the ABS pump to the master cylinder. The ABS is operated so that the wheel slippage can be maintained within a predetermined slippage criterion by reducing, holding, and increasing the wheel cylinder pressure in response to the road condition. Traditionally, the pressure intensifying valve and the pressure reducing valve are each comprised of a two-position electromagnetic solenoid valve. Alternatively, the pressure intensifying valve and the pressure reducing valve are both comprised of a single three-position solenoid valve. For instance, the pressure intensifying valve is closed and the pressure reducing valve is opened in order to control the wheel slippage within an acceptable slippage, when the wheel cylinder pressure is reduced during the anti-skid brake control. The auxiliary pump unit is usually referred to as an "ABS pump". One such ABS pump has been disclosed in Japanese Patent First Publication Tokkai Heisei No. 2-286883.
As shown in FIG. 4, the above-noted conventional ABS pump unit is comprised of a plunger pump. Referring now to FIG. 4, the plunger pump comprises a pump housing 1 defining a cylindrical hollow 2 therein, a cylinder 3 inserted and fixed into the cylindrical hollow 2, and a plunger 4 slidably enclosed in the cylinder 3. The pump housing 1 is integrally formed as the same housing as the pressure intensifying and reducing valve being comprised of a three-position solenoid valve, for example. As clearly seen in FIG. 4, the cylinder 3 has a radial opening 3a, while the plunger 4 is formed with a radial opening 4a and an axial bore 4b. The plunger pump includes a plunger biasing means, such as a coil spring 7 comprised of a compression spring, for normally biasing the plunger 4 to a drive cam 8. The plunger pump also includes a check valve means for regulating the outlet pressure of the plunger pump. The check valve means is comprised of an inlet check ball 6 and a coil spring 5 whose spring constant determines a setting pressure of the check valve means. Conventionally, the drive cam 8 is comprised of an eccentric cam having a driven connection with a direct current motor. The plunger pump is driven by virtue of the DC motor. During operation of the plunger pump, the brake fluid temporarily stored in the brake fluid reservoir is introduced through the radial openings 3a and 4a into the axial bore 4b. Thereafter, the brake fluid in the axial bore 4b is fed through the inlet check valve 6 and 5 to an outlet port of the plunger pump, in accordance with a reciprocating motion of the plunger 4.
As set forth above, since the plunger 4 of the prior art plunger pump is normally biased in a direction outwardly projecting from the interior of the cylinder 3 by means of the coil springs 7 and 5, when a sub-assembly being in a state wherein the plunger 4, the return spring 7 for the plunger, the inlet check ball 6, and the return spring 5 for the check ball 6 are all assembled in the cylinder 3, is inserted into the cylindrical hollow 2 of the housing, there is a tendency for the plunger 4 and the check ball 6 to fall out of the cylinder 3. Therefore, when assembling the sub-assembly with the housing, a working efficiency is lowered and consequently a manufacturing cost is increased. Due to the outwardly projecting plunger of the sub-assembly, a degree of freedom for assembling is limited. That is, although the sub-assembly can be upwardly assembled into the cylindrical hollow 2 of the housing 1 in its vertical direction, it is difficult to downwardly insert the sub-assembly into the cylindrical hollow 2 of the housing in a vertical direction or to horizontally insert the sub-assembly into the cylindrical hollow 2, because the plunger and the inlet check valve both tends to fall out of the cylindrical hollow of the pump housing. | {
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Directed audio systems allow a user to be located at nearly any point within an area and to listen to selected audio content while preventing others in the same area from hearing much or any of the audio content, without the aid of attachments such as headphones or any similar speaker based devices attached to the person or clothing of the user. A simple version of such a technology might be an array of speakers in a ceiling such that only one or more selected speakers located over the listener's location plays the audio content while all other speakers are silent, or alternatively play other audio content for other listeners. Another example of such technology is HyperSonic Sound (HSS)1, a technology used in products marketed by American Technology Corporation. HSS products convert an audio signal into a complex ultrasonic signal that is radiated from a transducer emitter. The signal may be tightly focused because it is highly directional. A listener in the path of the beam of ultrasonic energy is able to hear the audio signal while others outside the beam are unable to hear the signal or may hear it at a low level. The audible frequencies associated with the audio signal are created by interactions between different frequencies carried in the ultrasonic beam and air molecules which respond non-linearly to the ultrasonic frequencies. 1The product names used are for identification purposes only. All trademarks and registered trademarks are the property of their respective owners.
A related system is described in Austin Lowrey III, Apparatus and method of broadcasting audible sound using ultrasonic sound as a carrier, U.S. Pat. No. 6,052,336. Another system with similar goals is described in Wayne B Brunkan, Hearing system, U.S. Pat. No. 4,877,027.
Networks allowing the transmission of data are well known. Networks that are associated with mobile devices are well known, and examples are abundant. For example, a cellular telephone system is a network that allows mobile users to transmit and receive data, including, for example, digitized voice transmissions, text messages and other data. Other forms of wireless networking allow processor based devices of various type to intercommunicate with each other and with other networks, including for one example a wireless network that complies with the 802.11 family of standards. See for example, ISO/IEC 8802-11:1999(E) ANSI/IEEE Std 802.11. Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, 1 edition, 1999.
Some mobile device networks are persistent, that is, a node stays in a network as long as it is in the vicinity of a network access point and is operating; others may be spontaneous and short lived. For one instance a device may form a spontaneous, temporary network with another device when two devices are proximal and then disconnect when either device moves away, only to form another spontaneous network.
Locating devices are also well known. A common example of a locating device is a GPS receiver; because of the common knowledge of GPS receivers, this type of locating device is not further described here, except to note that GPS receivers work better outdoors, in general, than indoors.
Other forms of locating devices that work indoors or within a bounded area are also well known. Several classes of locating devices based on a radio source at the device or a radio-responsive circuit at the device are known. For one example, a cellular phone may be locatable based on the signal emitted by the cellular phone and its reception by locators. A wireless device such an 802.11 class transceiver on a wireless network may be similarly located. Even an un-powered device that has a Radio-Frequency Identification (RFID) circuit as a component may be locatable by other devices able to activate and read a signal from the activated RFID circuit. | {
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1. Field of the Invention
The present invention relates to a lithographic projection apparatus.
2. Description of the Related Art
The term xe2x80x9cpatterning devicexe2x80x9d as here employed should be broadly interpreted as referring to device that can be used to endow an incoming radiation beam with a patterned cross-section, corresponding to a pattern that is to be created in a target portion of the substrate. The term xe2x80x9clight valvexe2x80x9d can also be used in this context. Generally, the pattern will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit or other device (see below). An example of such a patterning device is a mask. The concept of a mask is well known in lithography, and it includes mask types such as binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid mask types. Placement of such a mask in the radiation beam causes selective transmission (in the case of a transmissive mask) or reflection (in the case of a reflective mask) of the radiation impinging on the mask, according to the pattern on the mask. In the case of a mask, the support structure will generally be a mask table, which ensures that the mask can be held at a desired position in the incoming radiation beam, and that it can be moved relative to the beam if so desired.
Another example of a pattering device is a programmable mirror array. One example of such an array is a matrix-addressable surface having a viscoelastic control layer and a reflective surface. The basic principle behind such an apparatus is that, for example, addressed areas of the reflective surface reflect incident light as diffracted light, whereas unaddressed areas reflect incident light as undiffracted light. Using an appropriate filter, the undiffracted light can be filtered out of the reflected beam, leaving only the diffracted light behind. In this manner, the beam becomes patterned according to the addressing pattern of the matrix-addressable surface. An alternative embodiment of a programmable mirror array employs a matrix arrangement of tiny mirrors, each of which can be individually tilted about an axis by applying a suitable localized electric field, or by employing piezoelectric actuators. Once again, the mirrors are matrix-addressable, such that addressed mirrors will reflect an incoming radiation beam in a different direction to unaddressed mirrors. In this manner, the reflected beam is patterned according to the addressing pattern of the matrix-addressable mirrors. The required matrix addressing can be performed using suitable electronics. In both of the situations described hereabove, the patterning device can comprise one or more programmable mirror arrays. More information on mirror arrays as here referred to can be seen, for example, from U.S. Pat. Nos. 5,296,891 and 5,523,193, and PCT patent applications WO 98/38597 and WO 98/33096, which are incorporated herein by reference. In the case of a programmable mirror array, the support structure may be embodied as a frame or table, for example, which may be fixed or movable as required.
Another example of a pattering device is a programmable LCD array. An example of such a construction is given in U.S. Pat. No. 5,229,872, which is incorporated herein by reference. As above, the support structure in this case may be embodied as a frame or table, for example, which may be fixed or movable as required.
For purposes of simplicity, the rest of this text may, at certain locations, specifically direct itself to examples involving a mask and mask table. However, the general principles discussed in such instances should be seen in the broader context of the patterning device as hereabove set forth.
Lithographic projection apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, the patterning device may generate a circuit pattern corresponding to an individual layer of the IC, and this pattern can be imaged onto a target portion (e.g. comprising one or more dies) on a substrate (silicon wafer) that has been coated with a layer of radiation-sensitive material (resist). In general, a single wafer will contain a whole network of adjacent target portions that are successively irradiated via the projection system, one at a time. In current apparatus, employing patterning by a mask on a mask table, a distinction can be made between two different types of machine. In one type of lithographic projection apparatus, each target portion is irradiated by exposing the entire mask pattern onto the target portion at once. Such an apparatus is commonly referred to as a wafer stepper. In an alternative apparatus, commonly referred to as a step-and-scan apparatus, each target portion is irradiated by progressively scanning the mask pattern under the projection beam in a given reference direction (the xe2x80x9cscanningxe2x80x9d direction) while synchronously scanning the substrate table parallel or anti-parallel to this direction. Since, in general, the projection system will have a magnification factor M (generally less than 1), the speed V at which the substrate table is scanned will be a factor M times that at which the mask table is scanned. More information with regard to lithographic devices as here described can be seen, for example, from U.S. Pat. No. 6,046,792, incorporated herein by reference.
In a known manufacturing process using a lithographic projection apparatus, a pattern (e.g. in a mask) is imaged onto a substrate that is at least partially covered by a layer of radiation-sensitive material (resist). Prior to this imaging, the substrate may undergo various procedures, such as priming, resist coating and a soft bake. After exposure, the substrate may be subjected to other procedures, such as a post-exposure bake (PEB), development, a hard bake and measurement/inspection of the imaged features. This array of procedures is used as a basis to pattern an individual layer of a device, e.g. an IC. Such a patterned layer may then undergo various processes such as etching, ion-implantation (doping), metallization, oxidation, chemo-mechanical polishing, etc., all intended to finish off an individual layer. If several layers are required, then the whole procedure, or a variant thereof, will have to be repeated for each new layer. Eventually, an array of devices will be present on the substrate (wafer). These devices are then separated from one another by a technique such as dicing or sawing, whence the individual devices can be mounted on a carrier, connected to pins, etc. Further information regarding such processes can be obtained, for example, from the book xe2x80x9cMicrochip Fabrication: A Practical Guide to Semiconductor Processingxe2x80x9d, Third Edition, by Peter van Zant, McGraw Hill Publishing Co., 1997, ISBN 0-07-067250-4.
For the sake of simplicity, the projection system may hereinafter be referred to as the xe2x80x9clens.xe2x80x9d However, this term should be broadly interpreted as encompassing various types of projection system, including refractive optics, reflective optics, and catadioptric systems, for example. The radiation system may also include components operating according to any of these design types for directing, shaping or controlling the beam of radiation, and such components may also be referred to below, collectively or singularly, as a xe2x80x9clensxe2x80x9d. Further, the lithographic apparatus may be of a type having two or more substrate tables (and/or two or more mask tables). In such xe2x80x9cmultiple stagexe2x80x9d devices the additional tables may be used in parallel or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposures. Dual stage lithographic apparatus are described, for example, in U.S. Pat. No. 5,969,441 and WO 98/40791, incorporated herein by reference.
A projection apparatus, such as used in lithography, generally includes an illumination system, referred to hereafter simply as an illuminator. The illuminator receives radiation from a source, such as a laser, and produces a projection beam for illuminating an object, such as the patterning device (e.g. a mask on a mask table). Within a typical illuminator, the beam is shaped and controlled such that at a pupil plane the beam has a desired spatial intensity distribution. This spatial intensity distribution at the pupil plane effectively acts as a virtual radiation source for producing the projection beam. A Following a first pupil plane, the radiation is substantially focused by a lens group referred to hereafter as xe2x80x9ccoupling Lensxe2x80x9d. The coupling lens couples the substantially focused radiation into an integrator, such as a quartz rod. The function of the integrator is to improve the homogeneity of the spatial and/or angular intensity distribution of the projection beam. The spatial intensity distribution at the pupil plane is converted to an angular intensity distribution at the object being illuminated by the coupling optics, because the pupil plane substantially coincides with the front focal plane of the coupling optics. Controlling the spatial intensity distribution at the pupil plane can be done to improve the processing latitudes when an image of the illuminated object is projected onto a substrate. In particular, spatial intensity distributions with dipole, annular or quadrupole off-axis illumination profiles have been proposed to enhance the resolution and other parameters of the projection, such as sensitivity to projection lens aberrations, exposure latitude and depth of focus.
A known illuminator comprises an optical system referred to hereafter as xe2x80x9czoom-axiconxe2x80x9d. The zoom-axicon is a device that adjusts the intensity distribution at the pupil plane. Radiation from the source passes through a first optical element such as, for example, a diffractive optical element (DOE), which generates an angular intensity distribution. Next, the radiation beam traverses a zoom lens. In the back focal plane of the zoom lens a spatial intensity distribution occurs that generally is suitable to serve as a secondary light source in the pupil plane. Hence the back focal plane of the zoom lens typically substantially coincides with the pupil plane (i.e. the front focal plane of the coupling optics). The outer radial extent of the spatial intensity distribution at the pupil plane can be changed by changing the focal length of the zoom lens. However, the zoom lens must have two degrees of freedom, one to change the focal length of the zoom lens and a second to change the position of the principal planes such that when the focal length changes, the back focal plane remains located at the pupil plane of the illuminator. Due to this functionality, the zoom lens typically consists of several (e.g. at least three) separate lenses in series, several of which are movable. As mentioned above, by tuning the focal length of the zoom lens, the radial extent of the intensity distribution at the pupil plane can be set. In the following, any preselected, preferred spatial intensity distribution at the pupil plane may be referred to as an xe2x80x9cillumination settingxe2x80x9d.
An axicon, which is located near the pupil plane, generally consists of two elements having complimentary conical shaped faces. The axicon is used to generate annular spatial intensity distributions, or other spatial intensity distributions with substantially no intensity around their center, i.e. no on-axis illumination. By tuning the distance between the two conical faces of the axicon, the annularity can be adjusted. When the axicon is closed, i.e. the gap between the conical faces is zero, conventional, (i.e. disc-like) illumination settings can be produced. With a gap between the conical faces, an annular intensity distribution results, with the inner radial extent of the annulus determined by the distance between the two conical faces. On the other hand the zoom lens determines the outer radial extent and thus the width of the annulus. Preselected inner and outer radial extents of the intensity distribution are often referred to as "sgr"-settings, in particular the "sgr"-inner settings and the "sgr"-outer setting, respectively. Here, "sgr"-inner and "sgr"-outer are a measure for the ratio of the radius in question to the maximum radius of the pupil.
The term xe2x80x9czoom-axiconxe2x80x9d as employed here should be interpreted as referring to a module comprising a zoom lens and an axicon.
Multiple illumination settings can be generated by various device in the known illuminator, for example by modifying the first optical element in front of the zoom lens, such as to appropriately shape the angular intensity distribution, or by inserting aperture plates or blades into the beam path, for instance near a pupil plane, and so on. Further information on a known zoom-axicon module and multipole mode generation are given (for example) in U.S. Pat. No. 6,452,662, incorporated herein by reference.
In the known illuminator, described above, it is apparent that to produce the desired range of illumination settings the zoom-axicon module will generally have several (e.g. five or more) optical components, which can make it expensive to produce, particularly given the fact that several of the elements must be independently movable. A further problem is that the lenses comprising the zoom lens and the two conical elements of the axicon represent a considerable thickness of lens material and a large number of surface interfaces. This means that the transmission efficiency can be poor due to absorption, reflection, inefficient coatings, degradation effects and contamination. This problem is exacerbated by the demand for imaging ever smaller features at higher densities, which requires the use of radiation with shorter wavelengths, such as 193, 157, 126 nm or even EUV (e.g. 5-20 nm). The efficiency of suitable transmissive materials, such as CaF2 and quartz, decreases at shorter wavelengths due to increased absorption and no materials are known that are sufficiently transmissive for EUV radiation. The effectiveness of the optical coatings of the components also typically decreases at shorter wavelengths and degradation effects generally become worse. Thus, overall, a significant throughput reduction can occur, due to decreased transmission. Another problem is that the known illuminator occupies a relatively large volume in the lithography apparatus. This in turn can lead to excess bulk in the machine, and increased manufacturing costs (particularly when using material such as CaF2).
As mentioned above, spatial intensity distributions with dipole, annular or quadrupole off-axis illumination profiles can enhance the projection properties. The choice of the profile depends on, amongst others, the respective application of the lithographic process. To provide a desired non-standard illumination mode for a given application, requires dedicated optical devices which must be specially designed at considerate effort and expense.
EP 0 744 641 A describes an illumination system for use in a lithography apparatus which uses a deformable mirror to improve the uniformity of illumination of the mask.
EP 0 486 316 A describes various different lithography apparatus including a variety of different arrangements for providing dipole and quadrupole illumination settings. These include arrangements using fiber bundles whose exit points are moveable to define the pole positions. Other arrangements use a mirror shiftable between two positions during an exposure or between shots of a multishot exposure.
An aspect of the present invention is to provide an improved lithography apparatus with an illuminator which avoids or alleviates the above problems. A further object is to provide devices which can be used to generate nearly any desired intensity distribution of the projection beam.
According to one aspect of the present invention there is provided a lithographic apparatus including a radiation system to provide a projection beam of radiation; a support structure for supporting a patterning device, the patterning device serving to pattern the projection beam according to a desired pattern; a substrate table to hold a substrate; a projection system to project the patterned beam onto a target portion of the substrate; wherein the radiation system comprises an illumination system configured to define the intensity distribution of the projection beam, wherein the illumination system comprises a steering device to individually steer different parts of an incoming beam into different directions to provide a desired angular intensity distribution of the projection beam at the patterning device, the steering device comprising a plurality of discrete mirrors, each for steering a part of the incoming beam and whose orientation can be controlled individually to direct the corresponding part of the incoming beam into a desired direction.
Another aspect of the present invention the plurality of discrete mirrors. Preferably, the discrete mirrors can be controlled to direct their corresponding part of the incoming beam into (substantially) any desired direction. The resulting angular intensity distribution can then be transformed into a spatial intensity distribution, for example by a focusing lens. Examples for a directing element are a reflecting element, which reflects the incident radiation into a direction or range of directions, and a diffractive element, which diffracts and thereby diverges the incident radiation. Any other type of element which is capable of directing radiation into a specific direction or range of directions or into plural directions can be used as a directing element, as long as the direction or the directions can be controlled. The control can be performed by any suitable way, for example mechanically to orient the directing element and/or electrically to directly or indirectly change the directing properties and/or the orientation of the directing element. Other methods for influencing the directing element and thereby setting the direction or directions are possible, such as methods using electromagnetic radiation or fields.
In recent times, micro-electromechanical and micro-opto-electro-mechanical systems (MEMS and MOEMS) have been developed for use as optical switches in devices for optical data transmission. Some of these MEMS comprise arrays with more than 1000 microscopic mirrors wherein each of the mirrors can be tilted in two different planes perpendicular to each other. Thus, radiation incident on such devices can be reflected into (substantially) any desired direction of a hemisphere. Such an array of reflective elements can be used as the plurality of discrete mirrors and are individually oriented to reflect projection radiation into different pre-determined directions.
An important advantage of the present invention lies in the fact that it can be applied to EUV radiation to provide desired intensity distributions. It has up to now not been possible to provide a zoom-axicon or equivalent device that would function with EUV radiation.
In a particular embodiment of the invention, the steering device includes a first faceted mirror, each of the discrete mirrors being a facet of the first faceted mirror and serving to project an image of a radiation source onto a selected facet of a second faceted mirror by control of the orientation thereof. In this arrangement, the first faceted mirror acts as a field mirror and a fly""s-eye reflector, creating a large number of virtual sources on the second faceted mirror which are then redirected to overlap on the mask, providing the desired uniformity of illumination. Preferably, the second faceted mirror is in a plane conjugate with a pupil plane of the projection system so that the illumination of the second faceted mirror determines the illumination mode of the mask. Thus, the illumination mode can be controlled by controlling the orientation of the facets of the first faceted mirror to illuminate selected ones of the facets of the second faceted mirror. This avoids the loss of beam intensity that would occur if the illumination mode is set by selective masking in a pupil plane.
The present invention is not limited to the case that the radiation system provides a single projection beam of radiation. Rather, different sub-beams or bundles of sub-beams can be generated at different locations and can be steered by the steering device to produce the desired angular intensity distribution. Furthermore, the projection beam or at least one of the projection beams can be split up to form separate sub-beams before reaching the directing elements. This means that the angular intensity distribution may be somewhat influenced by the manner in which the projection beam or projection beams is generated or manipulated before reaching the directing elements, but the control of the directing elements enables the user to produce the desired angular intensity distribution by choosing from a wide range of possible distributions. In particular, it is preferred that the directing elements can be controlled to direct each incident part of the projection radiation into (substantially) any direction of a hemisphere.
As described above, a desired spatial intensity distribution is to be produced in some cases. In these cases, it is preferred to produce a corresponding angular intensity distribution and to use a re-directing element to at least a part of the steered projection beam to produce the desired spatial intensity distribution in a cross-section of the projection beam, in particular in a focal plane. In particular, if focusing optical elements are used, such as a convex lens, each of the different directions of radiation propagation (of the produced angular intensity distribution) corresponds to one particular area of the spatial intensity distribution, in particular to one specific local point in a focal plane.
Different shapes and/or profiles of such a spatial intensity distribution such as annular, quadrupole, dipole and (soft) multipole, have been proposed. The present invention enables the user of a lithographic projection apparatus to produce any desired spatial intensity distribution, for example with arbitrary, definable shapes.
According to a preferred aspect of the invention, at least some of the sub-beams are steered and re-directed so that they correspond to spots or dashes of radiation in the cross-section in which the spatial intensity distribution is defined. Thus, the spatial intensity distribution has a profile with a discrete character. Depending on the size of the spots and/or dashes, and thereby depending on the size of the range of directions into which a single sub-beam is steered by the steering device, the spatial intensity distribution can comprise zones where the intensity is zero or almost zero (non-illuminated or dark zones) between illuminated areas.
In a preferred embodiment, the range of directions into which a single sub-beam propagates is influenced so that there is a sufficiently continuous intensity distribution. It is possible to influence the respective sub-beam or beams before the beam reaches the directing element and/or afterwards. In one particular embodiment, the sub-beams are steered so that they each propagate essentially to a single point. The points can be the same or different for the different sub-beams. One advantage of this embodiment is that the sub-beam can easily be adjusted to be incident on the directing element in the correct place. Further, undesired boundary effects due to radiation which is incident at the boundaries of the directing element can be reduced or avoided. For example, if the directing element is a reflective element with a given size of a reflective area, the arrangement can easily be adjusted so that the sub-beam is incident on the reflective element in the central zone of the reflective area.
To increase the range of propagation directions of the steered sub-beam, a diffuser device, such as a diffuser plate, can be used. However, this also may affect the polarization of the sub-beam and can make it difficult or impossible to exploit the polarization in subsequent stages.
In another embodiment, the sub-beam or beams are therefore manipulated before reaching the directing element or elements. In particular, the respective sub-beam is manipulated so that the steered sub-beam propagates into a defined range of propagation directions. For example, this can be done using a concentrating element to concentrate the sub-beam onto the directing element. The concentration also has the advantage that the sub-beam is incident on the directing element at the correct place, e.g. the central zone of a reflective area.
In addition or alternative to the embodiments described before, the range of propagation directions of the sub-beam or beams can be increased using the directing element or elements. In particular, the reflective surface area of a reflective element can be shaped accordingly, for example to have a convex shape.
The term xe2x80x9csub-beamxe2x80x9d as here employed should not be interpreted in a limiting way regarding the intensity distribution of the beam or beams before reaching the directing elements. Rather, the respective beam can be a single beam with a continuous intensity distribution, but, at the same time, can be considered to comprise a bundle of sub-beams. At least some of the sub-beams may become individual beams, separated from other parts of the beam, after being steered by the steering device. In any case, each steered sub-beam corresponds to a related part of the originally generated projection beam or beams.
Another aspect of the invention is that a variety of intensity distributions of the projection beam can be produced without the need to design corresponding optical arrangements especially for each one particular illumination setting and/or to replace at least parts of an existing optical arrangement. In particular, intensity distributions can be produced which previously existed only in theory.
According to a further aspect of the invention there is provided a device manufacturing method including providing a substrate at least partially with a layer of radiation-sensitive material; providing at least one projection beam of radiation; modifying the intensity distribution of the projection beam; using a patterning device to endow the modified projection beam with a pattern in its cross-section; projecting the patterned beam of radiation onto a target which comprises at least a part of the radiation-sensitive material, wherein the modification of the intensity distribution of the projection beam includes controlling the direction into which the radiation propagates, wherein the projection beam comprises a plurality of sub-beams, wherein at least some of the sub-beams are steered into different directions using a plurality of directing elements, and wherein the directing elements are individually controlled to direct the corresponding sub-beam into a desired direction.
According to still a further aspect of the invention there is provided a control system for controlling the intensity distribution of a beam of radiation for use in lithography including a calculation unit for calculating, based on a given intensity distribution of the beam, the necessary modifications to be made to the given distribution to produce a desired intensity distribution; an input device to input information about the desired intensity distribution; an output device to output a plurality of control signals to a plurality of directing elements which are capable of re-directing parts of the beam; wherein the calculation unit is adapted to calculate the control signals so that the directing elements can be controlled to modify the given intensity distribution of the beam to an angular intensity distribution which corresponds to the desired intensity distribution.
The calculation unit calculates the control signals based on a given intensity distribution. In particular, the given intensity distribution is applied in a projection beam of radiation which is used repeatedly to project the same pattern onto respective radiation-sensitive areas of one or more than one substrate. In one scenario, the given intensity distribution will be the same for each projection period, which may be interrupted by time periods with no illumination of radiation-sensitive material. However, it is also possible to employ different intensity distributions one after the other, using the same plurality of directing elements. In this case, the control system outputs different sets of control signals to the plurality of directing elements in order to change the angular intensity distribution between two projection periods.
In particular if the directing elements are electrically controlled, the illumination setting can be changed very quickly, due to the small mass and inertia of single, individually controllable directing elements compared to the mass and inertia of whole sets of optical elements, such as sets of diffractive optical elements with many microlenses. Thus, it is now possible to change the illumination setting between two flashes of illumination in acceptable time and to employ different intensity distributions alternatingly on a substrate.
According to a further aspect of the present invention there is provided a control system for controlling the intensity distribution of a beam of radiation for use in lithography including a calculation unit for calculating, based on a given intensity distribution of the beam, the necessary modifications to be made to the given distribution to produce a desired intensity distribution; an input device to input information about the desired intensity distribution; an output device to output a plurality of control signals to a plurality of discrete reflectors which are capable of re-directing parts of the beam, wherein the calculation unit is adapted to calculate the control signals so that the orientation of the discrete reflectors can be controlled to modify the given intensity distribution of the radiation beam to an angular intensity distribution which corresponds to the desired intensity distribution.
The control system may also be provided with an input device to receive the actually obtained mirror positions and/or pupil distribution so as to effect a closed loop control of the minor position and/or pupil distribution. The pupil distribution may be measured as described in European Patent Application No. 00307558.7, which is hereby incorporated by reference.
According to still a further aspect of the invention there is provided a computer program for producing a desired spatial intensity distribution of a beam of radiation for use in lithography, wherein an angular intensity distribution of radiation propagation of the beam corresponds to a spatial intensity distribution in a cross-section of the beam; and a steering device can be controlled to form an angular intensity distribution for any desired spatial intensity distribution by re-directing parts of the beam; the computer program comprising a code adapted to calculate the necessary state of the steering device and/or the control signals for controlling the steering device to form the angular intensity distribution which corresponds to the desired spatial intensity distributions.
In a preferred embodiment, an arbitrary spatial intensity distribution in a cross-section of the beam can be defined and the code is adapted to calculate the necessary state of the steering device and/or the control signals to form the corresponding angular intensity distribution.
In general, it is not possible to produce any theoretically possible angular intensity distribution. In particular, if the steering device includes directing elements as described above, there will be some discrete character of the intensity distribution due to the fact that each directing element directs the corresponding part of the beam into a limited range of directions only (see above). Depending on the number of directing elements, on their characteristic properties, and other factors, the discrete character of the intensity distribution will be more or less pronounced. It is preferred that the code of the computer program take the discrete character into account and calculate the necessary state of the steering device and/or the control signals which result in the closest approximation of the angular intensity distribution which is equivalent to the desired spatial intensity distribution.
Preferably, in order to increase the number of spatial intensity distributions which can be produced by transforming the angular intensity distribution to the corresponding spatial intensity distribution, the optical elements (e.g. zoom lens) which transforms the angular intensity distribution to the spatial distribution can be modified and/or exchanged. In this case, the computer program must have access to the amended transformation behavior. In a preferred embodiment, the code is adapted to choose between different transformation arrangements and/or properties of transformation arrangements and are adapted to calculate not only the state of the steering device and/or the control signals for controlling the steering device, but are also adapted to calculate the corresponding transformation arrangement which produces the desired spatial intensity distribution. For example, the transformer may include a zoom lens and the code are then adapted to choose or calculate an appropriate value of the focal length of the zoom lens.
Alternatively, or as an added feature, it is possible that the code can choose between different arrangements for influencing the projection beam before it reaches the steering device.
Although specific reference may be made in this text to the use of the apparatus according to the invention in the manufacture of ICs, it should be explicitly understood that such an apparatus has many other possible applications. For example, it may be employed in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, liquid-crystal display panels, thin-film magnetic heads, etc. One of ordinary skill will appreciate that, in the context of such alternative applications, any use of the terms xe2x80x9creticlexe2x80x9d, xe2x80x9cwaferxe2x80x9d or xe2x80x9cdiexe2x80x9d in this text should be considered as being replaced by the more general terms xe2x80x9cmaskxe2x80x9d, xe2x80x9csubstratexe2x80x9d and xe2x80x9ctarget portionxe2x80x9d, respectively.
In the present document, the terms xe2x80x9cradiationxe2x80x9d and xe2x80x9cbeamxe2x80x9d are used to encompass all types of electromagnetic radiation, including ultraviolet radiation (e.g. with a wavelength of 365, 248, 193, 157 or 126 nm) and EUV (extreme ultra-violet radiation, e.g. having a wavelength in the range 5-20 nm), as well as particle beams, such as ion beams or electron beams. | {
"pile_set_name": "USPTO Backgrounds"
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Conventional in-window air conditioners tend to be loud (often in the 50-60 dB range), large, and heavy. Installation of such an air conditioner within a window can be difficult due to its weight and bulk. Once installed, the air conditioner blocks visibility through the portion of the window occupied by the air conditioner. When occupied by an air conditioner, the window may also otherwise be non-functional; that is, while the air conditioner is installed, it may not be possible to safely open the window for fresh air. Further, air conditioners are typically made a standard size and have expandable spacers on one or both sides to allow the air conditioner to laterally fill a space created by opening the window to accommodate the air conditioner. Such spacers are typically poor insulators, allowing heat to enter the room being cooled by the air conditioner. Further, conventional in-window air conditioners tend to rely exclusively on a refrigeration cycle using a refrigerant, compressor, and expansion valve. Such an arrangement may not be efficient in certain temperature environments. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates generally to the field of image sensors and, more particularly, to such image sensors having a capacitive control gate for eliminating an undesired capacitive effect caused by a reset gate on a floating diffusion and controlling the capacitance of a floating diffusion.
As shown in FIGS. 1 and 2, prior art charge-coupled devices 10 typically include a substrate 20 of a p-type having a buried channel 30 of the n-type for transferring charge packets of electrons. A plurality of gates 40 (two gates for the two-phase device shown in FIG. 1) are connected to the buried channel 30 for controlling charge packet transfer in the buried channel 30. A non-clocked output gate 50 is positioned between one of the gates 40a and a floating diffusion 60 for preventing capacative coupling of the last clocked gate 40a to the floating diffusion 60.
The floating diffusion 60 provides a mechanism for sensing the size of the charge packet for subsequent measurement and the like. A reset transistor 70 provides a mechanism for resetting the voltage level of the floating diffusion after appropriate sampling. A reset drain 80 is adjacent the reset transistor 70 for receiving drained charge from the floating diffusion 60, as is well known in the art.
Referring to FIG. 3, a typical timing sequence of the charge-coupled device 10 is shown. At time T0, the reset gate 70 is clocked high. This turns on the reset transistor 70 and resets the floating diffusion 60 to the reference voltage of the reset drain 80. Then at time T1, the reset gate 70 is clocked low. Capacitive coupling (represented by Creset) between the reset gate 70 and the floating diffusion 60 causes the voltage of floating diffusion 60 to be pushed to a more negative voltage when the reset gate 70 is turned off. The floating diffusion 60 voltage then remains stable and is sampled at time T2. Then at time T3, the gates 40 are clocked which changes their levels and transfers a new charge packet over the output gate 50 and onto the floating diffusion 60. The magnitude of the voltage change at time T3 on the floating diffusion 60 is proportional to the size of the charge packet and the capacitance of the floating diffusion 60. The relationship is given by V=Q/C where V is the voltage change, Q is the size of the charge packet (coulombs), and C is the capacitance of the floating diffusion (farads). The new voltage on the floating diffusion 60 is sampled at time T4 and then the timing cycle is repeated.
Although the currently known and utilized sensor and associated method for transferring charge is satisfactory, it includes drawbacks. The shortcoming of the output structure is the capacitive coupling of the reset gate to the floating diffusion, which causes the voltage glitch between times T0 and T1 on the amplifier input node. This short glitch also restricts the type of electronics that are used to process the output signal of the CCD. Another disadvantage of the prior art is the voltage change of the floating diffusion is fixed to a constant value by the floating diffusion capacitance. Consequently, it is desirable to have a structure, which allows the voltage gain to be changed for some means of altering the floating diffusion capacitance, and which eliminates undesired capacative coupling of the reset gate 70.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, the invention is a charge-coupled device having a plurality of cells for forming the charge-coupled device, each of the cells capable of retaining charge; a transfer mechanism within the charge-coupled device for moving charge through the plurality of cells; an output region for receiving charge moved through the plurality of cells under control of the transfer mechanism; a floating diffusion to receive charge moved across the output region; a reset gate to remove charge from the floating diffusion and reset the floating diffusion to a reference voltage level; and a capacitance control gate adjacent to the floating diffusion for canceling capacitance coupling of the reset gate. A capacitance control gate covers a portion of the floating diffusion and the voltage of the capacitance control gate is adjusted to alter the capacitance of the floating diffusion. The capacitance control gate is clocked opposite that of the reset gate to cancel the capacitive effects of the reset gate.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
The present invention has the following advantages of producing a smoother waveform going to the CCD amplifier input, which is easier for the electronics of the camera to process. The present invention also provides a means for changing the effective gain of the CCD output. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention generally relates to low VOC (volatile organic component) high solids coating compositions and more particularly to fast-drying two-component compositions suited for automotive coatings.
The time needed before a primer-surfacer on an auto body surface can be sanded after application, without fouling the sandpaper, is becoming increasingly important since it determines how many cars can be repaired per day. It is typical for traditional two-pack (2K) non-isocyanate-based thermoset resin systems to employ polyacrylics containing pendant acetoacetate (AcAc) groups as zone component of the binder resin and an amine and/or ketimine oligomer and/or polymer as the other. However, such an approach does not provide sufficiently rapid formation of robust coatings that can be sanded easily since viscosity restrictions imposed by the Environmental Protection Agency of the United States (EPA) must be adhered to (xe2x89xa64.8 lbs. volatile organic content (VOC)/gallon).
Several attempts have been made to produce rapid formation of coatings. U.S. Pat. No. 4,772,680 (hereafter ""680 patent) discloses polymers of average molecular weight in the range 1000 to 100,000. However, to comply with the EPA regulation above, the average molecular weight must actually be less than about 45,000, otherwise the coating composition becomes too viscous to be of practical use or has a very short pot life of less than 30 minutes. One approach to overcome this problem is to utilize coatings composition containing polymers having high. glass transition temperatures (Tgs). However, with the ever increasing restrictions on the permissible amount of the VOC that can be released in the atmosphere and attendant molecular weight limitations, it is becoming more difficult to polymerize polymers having Tg""s above 40xc2x0 C. and having sufficient pendant AcAc groups (e.g., 10 to 40% by weight). Such polymers having the desired cross-link density are required to achieve good repair durability. Therefore, one cannot apply the teaching of the ""680 patent for polymers with Tg""s above about 40xc2x0 C. and still meet the EPA restrictions. The instant invention provides for coating compositions containing high Tg polymers and it represents a significant advance over the teachings of the ""680 patent.
The present invention is directed to a coating composition comprising:
a crosslinking component comprising a polyamine, a polyketimine, or a combination thereof, wherein said polyamine has an average of at least two amine functionalities per polyamine molecule and wherein said polyketimine has an average of at least two ketimine functionalities per polyketimine molecule; and
a binder component comprising:
a polyacetoacetate having at least two acetoacetate functionalities, said polyacetoacetate being polymerized from a monomer mixture comprising a methacrylate monomer, a styrene monomer, or a combination thereof, said methacrylate and styrene monomers each having a bulky pendant moiety, wherein a coating from said coating composition at a two-hour cure has a Persoz hardness of about greater than or equal to 60 for a dry film thickness of greater than or equal to 40 microns.
The present invention is also directed to a method of producing a coating on a substrate, said method comprising:
mixing a crosslinking component with a binder component to form a pot mix, said crosslinking component comprising a polyamine, a polyketimine, or a combination thereof, said polyamine having an average of at least two amine functionalities per polyamine molecule and said polyketimine having an average of at least two ketimine functionalities per polyketimine molecule; said binder component comprising a polyacetoacetate having at least two acetoacetate functionalities, said polyacetoacetate being polymerized from a monomer mixture comprising a methacrylate monomer, a styrene monomer, or a combination thereof, said methacrylate and styrene monomers each having a bulky pendant moiety;
applying a layer of said pot mix on said surface; and
curing said layer under ambient conditions to form said coating on said surface of said substrate, said coating at a two-hour cure has a Persoz hardness of about greater than or equal to 60 for a dry film thickness of greater than or equal to 40 microns.
One of the advantages of the present invention is its low VOC, which is significantly below the current guidelines of the EPA.
Another advantage of the composition of the present invention is that it is free from isocyanate groups. As a result, it has less toxicity than conventional polyurethane coatings prepared from isocyanate group-containing compounds. This reduced toxicity is particularly helpful for auto paint repair shops that may not have physical facilities required to handle more toxic compositions containing isocyanate functionalities.
Yet another advantage of the composition of the present invention is that it reduces the time-to-sand, before the coating can be sanded without fouling the sandpaper, thereby increasing the number of repairs that could be performed in a day.
Still another advantage of the composition of the present invention is that it does not release pungent odors often associated with low molecular weight compounds containing acrylate functional moieties. Compounds such as these are employed in some of the conventional low VOC non-isocyanate containing coating compositions.
As defined herein:
xe2x80x9cTwo-pack coating compositionxe2x80x9d means a thermosetting composition comprising two components that are stored in separate containers, which are typically sealed for increasing the shelf life of the components of the coating composition. The components are mixed just prior to use to form a pot mix, which has a limited pot life, typically a few minutes, such as 15 minutes to 45 minutes to a few hours, such as 2 hours to 6 hours. The pot mix is applied as a layer of desired thickness on a substrate surface, such as an autobody. After application. the layer dries and cures to form a coating on the substrate surface having desired coating properties, such as solvent resistance.
xe2x80x9cLow VOC coating compositionxe2x80x9d means a coating composition that is less than about 0.6 kilogram of organic solvent per liter (4.8 pounds per gallon) of the composition, as determined under the procedure provided in ASTM D3960.
xe2x80x9cHigh solids compositionxe2x80x9d means a coating composition having a solids component of above 20 percent, preferably in the range of from 25 to 95 percent and more preferably in the range of from 30 to 80 percent, all in weight percentages based on the total weight of the composition.
xe2x80x9cGPC weight average molecular weightxe2x80x9d means a weight average molecular weight measured by utilizing gel permeation chromatography. A high performance liquid chromatograph (HPLC) supplied by Hewlett-Packard, Palo Alto, Calif. was used. Unless stated otherwise, the liquid phase used was tetrahydrofurane and the standard was polymethyl methacrylate.
xe2x80x9cPolydispersityxe2x80x9d means GPC weight average molecular weight divided by GPC number average molecular weight.
xe2x80x9cPolymer solidsxe2x80x9d or xe2x80x9cBinder solidsxe2x80x9d means a polymer or binder in its dry state.
xe2x80x9cBulky pendent moietyxe2x80x9d means a group on a polymer that restricts segmented motion of the polymer backbone.
The present invention is directed to a coating composition suited for various coating processes, particularly in automotive refinishing processes used for coating autobodies. The composition is a two-pack composition, which includes a crosslinking component and a binder component.
Typically, about a 3-hour cure time is required for conventional polyacetoacetate-ketimine binder systems, before coatings therefrom can be sanded without fouling the sandpaper. However, a need exists for a coating composition that provides for a coating that can be sanded in 1 hour or less without adversely affecting holdout [i.e., distinctness of image (DOI) and feather-edge holdout (FIE)] once it is topcoated with a base coat and a clear coat, or with a single-stage coat. One approach to achieve this end is to increase the glass transition temperature (Tg) of the polyacetoacetate. However, the amount of monomer containing the cross-linkable moiety, e.g., AcAc-functionalized monomer, must be maintained in the range of from about 10 to 80 weight percent to provide sufficient cross-linking so that holdout is not adversely affected. The foregoing weight percent range is important for avoiding lacquer-type primer-surfacer behavior with very little or no cross-linking in which the DOI and FIE holdout are poor due to solvent swelling after topcoat application. Furthermore, the molecular weight for conventional spraying will be in the range of about 5,000 to 50,000, or else the viscosity is too high to be used in a primer-surfacer formulation that adheres to current Environmental Protection Agency (EPA) restrictions (i.e., 4.8 VOC or less).
We have made an unexpected discovery that permits the use of a polyacetoacetate polymerized from sufficient amount of cross-linkable monomer (e.g., 10 to 80% of AcAc-functionalized monomer) for providing good DOI and F/E holdout, having a reasonable molecular weight (5,000 to 50,000) so that it can be readily applied by conventional spray gun, and having sufficiently high Tg (e.g., 40xc2x0 to 150xc2x0 C.) to provide a fast drying two pack coating composition that yields a coating that sands well (i.e., no fouling of the sandpaper occurs) at a short cure time of about an hour. We discovered that the foregoing results could be accomplished by incorporating high Tg (rigid) bulky monomers in the polyacetoacetate used in the coating composition of the present invention to provide the resulting polyacetoacetate with bulky pendent moieties. The coating from the coating composition of the present invention has a Persoz hardness of about greater than or equal to 60, preferably in the range of from 60 to 150, more preferably in the range of 70 to 120 for a dry film thickness of greater than or equal to 40 microns.
The coating composition includes in the range of from 10 percent to 90 percent, preferably in the range of from 10 percent to 70 percent and more preferably in the range of from 15 percent to 60 percent of the crosslinking component, the percentages being in weight percentages based on the total weight of binder and crosslinking components solids.
The crosslinking component includes a polyamine, a polyketimine, or a combination thereof. Polyketimine is preferred. When used as a combination of a polyamine and a polyketimine, the ratio thereof by weight parts is in the range from 1 to 100 through 100 to 1, preferably in the range of from 1 to 50 through 50 to 1, more preferably in the range of from 1 to 20 through 20 to 1.
The polyamine has a weight average molecular weight of at least 100, as determined by gel permeation chromatography using polymethyl methacrylate standards. Typically, the GPC weight average molecular weight ranges from about 100 to about 100,000, preferably from about 200 to about 50,000 and more preferably from about 300 to about 10,000.
The polyamine has an average of at least two amine functionalities per molecule, which may be primary, secondary or a combination of secondary and primary amine functionalities. Preferably, the polyamine has an average of from about 2 to about 25 and more preferably, in the range of from about 2 to about 6 amine functionalities per polyamine molecule and has 2 to 200, preferably 6 to 100 and more preferably 8 to 50 carbon atoms. These amine functionalities may be present either as pendant functionalities or amine functionalities positioned in the backbone of the polymer chain. Pendent amine functionalities are preferred.
Examples of representative polyamines suitable for use in the invention include aliphatic or cycloaliphatic amines, or a combination thereof. The aliphatic polyamine is preferred.
Examples of suitable polyamines include primary and secondary amines, such as, ethylenediamine, propylenediamine, butylenediamine, pentamethylenediamine, hexamethylenediamine, decamethylenediamine, 4,7-dioxadecane-1,10-diamine, dodecamethylenediamine, 4,9-dioxadodecane- 1,12-diamine, 7-methyl-4,10-dioxatridecane-1,13-diamine, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, 4,4xe2x80x2-diminodicyclohexyl methane, isophorone diamine, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, nitrile tris(ethane amine), bis(3-aminopropyl)methylamine, 3-amino-1-(methylamino)propane, 3-amino-1-(cyclohexylamino)propane, and N-(2-hydroxyethyl)ethylene diamine. Ethylenediamine, propylenediamine, butylenediamine and 1,2-diaminocyclohexane are preferred.
Other suitable polyamines include those of the formula:
H2Nxe2x80x94(R2)nxe2x80x94NHxe2x80x94(R1)nxe2x80x94NH2,
where the R1 and R2 groups may be the same or different and represent an alkylene group containing 2 to 6 and preferably 2 to 4 carbon atoms and n is an independently selected number in the range of from 1 to 6 and preferably in the range of from 1 to 3. The alkylene group is a cycloalkylene group or an alkylene group containing an ether-oxygen atom. Examples of representative polyamines containing polyalkylene groups include diethylene triamine, dipropylene triamine and dibutylene triamine. It is preferred that these polyamines should be of a cycloaliphatic nature and contain 5 to 15 carbon atoms. such as isophoronediamine; more particularly containing an alpha-aklyl group, such as bis(3-methyl-4-aminocyclohexyl)methane and bis(3-methyl4-aminocyclohexyl)propane.
Other suitable polyamines include reaction products of primary or secondary polyamines, such as ethylene diamine, diethylene triamine and isophorone diamine, with polyfunctional epoxy, isocyanate, maleinate, fumarate, acryloyl, methacryloyl, or a combination thereof.
Some of the suitable polyepoxides include those containing at least two oxirane groups in the molecule, i.e.,
where n is at least two, R1 is hydrogen or methyl, and R2 broadly represents an organic based molecule or polymer typically composed of carbon, hydrogen, oxygen, and optionally nitrogen, sulfur, or both. Hydroxyl substituent groups may also be present, as well as halogen and ether groups. Generally, the epoxide equivalent weight ranges from about 100 to about 1500, preferably from about 100 to about 1200, and more preferably from about 150 to about 600. These polyepoxides can be broadly categorized as being aliphatic, aromatic, cyclic, acyclic, alicyclic or heterocyclic.
Another group of useful polyepoxides for use in the present invention includes epoxy novalac resins. These resins are prepared by reacting an epihalohydrin with the condensation product of an aldehyde with a monohydric or polyhydric phenol. One example is the reaction product of epichlorohydrin with a phenolformaldehyde condensate.
Another particularly preferred group of the polyepoxides are the polyglycidyl ethers of polyhydric aromatic hydroxy compounds, such as for example, dihydric phenols. The phenol must be at least dihydric, such as, for example, resorcinol, catechol, hydroquinone, bis(4-hydroxyphenyl)-1,1-isobutane; 4,4-dihydroxybenzophenone; bis(4-hydroxyphenyl)1,1-isobutane; 4,4-dihydroxybenzophenone; bis(4-hydroxyphenyl)-1,1-ethane; bis(2-hydroxynaphenyl)methane; 1,5-hydroxynaphthalene and 4,4xe2x80x2-isopropylidenediphenol, i.e., bisphenol A. Preferably bisphenol A is utilized. Of the many polyepoxides possible, the one principally utilized is epichlorohydrin although epibromohydrin is also quite useful. The polyglycidyl ethers especially useful herein are obtained by reacting epichlorohydrin and bisphenol A in the presence of an alkali, such as sodium or potassium hydroxide. The series of epoxy resins sold by Shell Chemical Company under the trademark EPON are especially useful herein.
Another group of useful polyepoxides are the polyglycidyl ethers derived from reacting epihalohydrin, preferably epichlorohydrin, with polyhydric alcohols, such as ethylene glycol; diethylene glycol; triethylene glycol; 1,2-propylene glycol; 1,4-butylene glycol; 1,5-pentanediol; 1,2,6-hexanetriol; glycerol and trimethylolpropane.
Also useful are the polyepoxides which are polyglycidyl ethers of polycarboxylic acids. These materials are produced by the reaction of an epoxy compound, such as epichlorohydrin with an aliphatic or aromatic polycarboxylic acid such as oxalic acid; succinic acid; glutaric acid; terephthalic acid; 2,6-naphthalene dicarboxylic acid and dimerized linoleic acid.
Still another group of polyepoxides are derived from epoxidation of olefinically unsaturated alicyclic materials. Among these are the epoxy alicyclic ethers and esters, which are well known in the art.
It should be understood that mixtures of the polyepoxides are also useful herein. The preferred epoxy equivalent weight of the polyepoxide(s) is in the range of from 87 to 6000, more particularly the range of from 120 to 1000. suitable polyoxides include those containing oxyalkylene groups, i.e.,
wherein R is hydrogen or C1 to C6 alkyl, m is an integer varying from 1 to 4 and n is an integer varying from 2 to 50. The proportion of oxyalkylene groups in the polyepoxide depends upon a number of factors, among them the size of the oxyalkylene group and the nature of the polyepoxide.
Examples of suitable polyisocyanates include aliphatic, cycloaliphatic or aromatic di-, tri- or tetraisocyanates which may or may not be ethylenically unsaturated, such as 1,2-propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, 2,3-butylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, dodecamethylene diisocyanate, omega, omega-dipropyl ether diisocyanate, 1,3-cyclopentane diisocyanate, 1,2-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4-methyl-1,3-diisocyanatocyclohexane, trans-vinylidene diisocyanate, dicyclohexylmethane-4,4xe2x80x2-diisocyanate, 3,3xe2x80x2-dimethyl-dicyclohexylmethane-4,4xe2x80x2-diisocyanate, a toluene diisocyanate, 1,3-bis(1-isocyanato 1-methylethyl)benzene, 1,4-bis(1-isocyanato-1-methylethyl)benzene, 1,3-bis(isocyanatomethyl)benzene a xylene diisocyanate, 1,5-dimethyl-2,4-bis(isocyanatomethyl)benzene, 1,5-dimethyl-2,4-bis(2-isocyanatoethyl)benzene, 1,3,5-triethyl-2,4-bis(isocyanatomethyl)benzene, 4,4xe2x80x2-diisocyanatodiphenyl, 3,3xe2x80x2-dichloro-4,4xe2x80x2-diisocyanatodiphenyl, 3,3xe2x80x2-diphenyl4,4xe2x80x2-diisocyanatodiphenyl, 3,3xe2x80x2-dimethoxy-4,4xe2x80x2-diisocyanatodiphenyl, 4,4xe2x80x2-diisocyanatodiphenylmethane, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-diisocyanatodiphenyl methane, a diisocyanatonaphthalene, polyisocyanates having isocyanaurate structural units, the adduct of 2 molecules of a diisocyanate, such as hexamethylene diisocyanate or isophorone diisocyanate, and a diol such as ethylene glycol, the adduct of 3 molecules of hexamethylene diisocyanate and 1 molecule of water (available under the trademark Desmodur(copyright) N from Bayer Corporation of Pittsburgh, Pa.), the adduct of 1 molecule of trimethylol propane and 3 molecules of toluene diisocyanate (available under the trademark Desmodur(copyright) L from Bayer Corporation ), the adduct of 1 molecule of trimethylol propane and 3 molecules of isophorone diisocyanate, compounds such as 1,3,5-triisocyanato benzene and 2,4,6-triisocyanatotoluene, and the adduct of 1 molecule of pentaerythritol and 4 molecules of toluene diisocyanate.
Examples of suitable polyacrylates or polymethacrylates include polymerized monomers, such as acrylic or methacrylic esters of a mono-, di- or polyfunctional hydroxyl compound including methyl acrylate, methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, propyl acrylate, hydroxypropyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isobornyl acrylate, oleyl acrylate, glycidyl methacrylate or (meth)acryloxypropyl trimethoxysilane.
The polyketimines, which are suitable for use in the present invention, are obtained by blocking the amino groups on the aforedescribed polyamines with a blocking agent, such as a ketone having not more than 18 carbon atoms, preferably 3 to 10 carbon atoms. The polyketimine suitable for use in the coating composition of the present invention has a weight average molecular weight in the range of from 100 to 100,000.
The polyamine is preferably blocked with a ketone represented by the following formula:
wherein R and Rxe2x80x2 are independently selected alkyl groups having between 1 and 12, preferably 1 to 8 carbon atoms. An aliphatic or cycloaliphatic ketone is preferred and an aliphatic or cycloaliphatic ketone with 3 to 8 carbon atoms is more preferred.
The polyamine suitable for use in the coating composition of the present invention includes:
I. an adduct of an amine of diglycidyl ether based on bis(4-hydroxyphenyl)-2,2-propane;
II. an adduct of an amine and dimethyl maleate; or
III. an adduct of an amine prepared from a polyacrylate having at least two acrylate groups per molecular and having a weight molecular weight from about 100 to 50,000.
Examples of suitable blocking agents for the amino groups include acetone, diethyl ketone, methylisobutyl ketone, isobutyraldehyde, hydroxybutyraldehyde, pentanone, cyclohexanone, ethylamyl ketone, hydroxycitronellal, isophorone and decanone.
The binder component of the coating composition includes in the range of from percent 1 percent to 90 percent, preferably in the range of from 5 percent to 80 percent and more preferably in the range of from 20 percent to 60 percent of at least one polyacetoacetate, the percentages being in weight percentages based on the total weight of binder solids. The polyacetoacetate has at least 2, preferably in the range of from 2 to 30, more preferably in the range of 2 to 25 and still more preferably in the range of 2 to 10 and most preferably in the range of acetoacetate groups. The polyacetoacetate has a GPC weight average molecular weight in the range of from 100 to 50,000, preferably in the range of from 200 to 40,000 and more preferably in the range of from to 1000 to 35,000. The polyacetoacetate has an acetoacetate equivalent weight (grams/equivalent) from about 100 to about 1500, preferably from about 100 to about 1000 and more preferably from about 200 to about 950. The polyacetoacetate has a Tg in the range of from 40xc2x0 C. to 150xc2x0 C., preferably in the range of from 50xc2x0 C. to 100xc2x0 C. and more preferably in the range of from 55xc2x0 C. to 90xc2x0 C.
The equivalent ratio of the amine in polyamine or polyketimine to polyacetoacetate is in the range of from 0.3 to 2.5, preferably in the range of from 0.5 to 2.0 and more preferably I the range from 0.6 to 1.8.
The polyacetoacetate is polymerized from a monomer mixture that includes in the range of from 5 percent to 90 percent, preferably in the range of from 10 percent to 70 percent, and more preferably in the range of from 15 percent to 60 percent of an acetoacetate-functionalized monomer. All percentages being in weight percent based on the total binder component solids weight.
The aforedescribed monomer mixture further contains in the range of from 5 percent to 90 percent, preferably in the range of from 10 percent to 70 percent, and more preferably in the range of from 15 percent to 60 percent of a methacrylate monomer, a styrene monomer, or a combination thereof, each provided with a bulky pendent moiety.
Examples of suitable methacrylate monomers having the bulky pendent moiety includes isobornyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, t-butyl methacrylate or a combination thereof.
Examples of suitable styrene monomer having the bulky pendent moiety include t-butyl styrene, more particularly para-tertiary-butylstyrene supplied by Deltech Corporation, Baton Rouge La.
The aforedescribed monomer mixture may include 5 percent to 90 percent, preferably in the range of from 10 percent to 70 percent and more preferably in the range of from 15 percent to 60 percent of an acetoacetic ester of a hydroxyalkyl (meth)acrylate or allyl alcohol monomer unit, all percentages being in weight percentages based on the total weight of the monomer mixture.
If desired the monomer mixture may contain 0.1 percent to 90 percent, preferably in the range of from 5 percent to 80 percent and more preferably in the range of from 10 percent to 70 percent of an acrylic or methacrylic ester of a mono-, di- or polyfunctional hydroxyl compound having 1 to 18, preferably 2 to 10 carbon atoms, all percentages being in weight percentages based on the total weight of the monomer mixture. Some of the examples of the acrylic or methacrylic esters include methyl acrylate, methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, propyl acrylate, hydroxypropyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isobornyl acrylate, oleyl acrylate, glycidyl methacrylate and (meth)acryloxypropyl trimethoxysilane.
If desired the monomer mixture may further contain 0.1 percent to 20 percent, preferably in the range of from 1 percent to 15 percent and more preferably in the range of from 1 percent to 12 percent of a monoethylenically unsaturated mono- or dicarboxylic acid having 3 to 12, preferably 3 to 10 carbon atoms or an anhydride thereof, all percentages being in weight percentages based on the total weight of the monomer mixture. Some of the examples of such acids or anhydrides thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, cinnamic acid or dodecenic acid. Acrylic acid and maleic anhydride are preferred.
If desired the monomer mixture may contain 0.1 percent to 90 percent by weight of one or more other copolymerizable monomers, such as styrene, xcex1-methyl styrene, vinyl toluene, acrylamide, methacrylamide, acrylonitrile, vinyl acetate, vinyl versatate, vinyl trimethoxy silane and/or allyl glycidyl ether. These monomer units are obtained for instance by acetoacetylation of an adduct of a lactone, a monoepoxy compound or a diisocyanate reacted with a diol to a hydroxyalkyl (meth)acrylate. Examples of other suitable monomer units include allyl acetacetate and acetoacetic esters of ethylenically unsaturated diols or triols such as 2-butene-1,4-diacetoacetate and (2-methylene acetoacetyl)-1-propene-3-acetoacetate.
The polyacetoacetate may be prepared in any convenient manner, for instance by polymerizing one or more acetoacetate groups-containing monomer, optionally mixed with one or more other aforedescribed monomers, at a temperature of 50xc2x0 to 160xc2x0 C., in the presence of 0.1-10% by weight of an initiator, calculated on the total amount of the monomer mixture. Examples of suitable initiators include free radical initiators, for instance potassium persulfate, hydrogen peroxide, cumene hydroperoxide, benzoyl peroxide, ditert-butyl peroxide, tert-butylpertrimethyl hexanoate, tert-butyl perbenzoate, azobisisobutyronitrile, azobisvaleronitrile, azobis(2,4-dimethylvaleronitrile). The polymerization is carried out in the presence of water and/or an organic solvent, such as ketone, an alcohol, an ether, an ester or a hydrocarbon. The polymerization can optionally be carried out by using UV light and in the presence of UV initiators, such as benzil, benzoin ethers and thioxanthone derivatives.
Other suitable polyacetoacetate are addition polymers having, for instance hydroxyl groups, a number of which have been converted with a reactive acetoacetate compound or a compound yielding an acetoacetate group, for instance with diketene. Examples of suitable reactive acetoacetate compounds include alkyl esters of acetylacetic acid, preferably methyl acetoacetate or ethyl acetoacetate. Suitable hydroxyl groups-containing addition polymers include copolymers of a hydroxyalkyl (meth)acrylate such as hydroxyethyl methacrylate, hydroxypropyl methacrylate and/or hydroxybutyl acrylate and optionally one or more other comonomers, and copolymers of styrene and allyl alcohol.
If desired, the binder and the crosslinking component of the coating composition may contain at least one organic solvent. Suitable examples include water, aromatic hydrocarbons, such as petroleum naphtha or xylenes; aliphatic hydrocarbons; ketones, such as methyl amyl ketone, methyl isobutyl ketone, methyl ethyl ketone or acetone; diketo compounds, such a acetyl ketone; nitroalkanes, such as nitropropane; esters, such as butyl acetate or hexyl acetate; glycol ether esters, such as propylene glycol monomethyl ether acetate; and (cyclo)aliphatic or aromatic esters of acetylacetic acid, of which the (cyclo)alkyl group or the aromatic group has 1 to 20 carbon atoms, such as ethylacetoacetate, cyclohexylacetoacetate and phenylacetoacetate. The amount of organic solvent added depends upon the desired solids level as well as the desired amount of VOC of the composition. If desired, the organic solvent may be added to both components of the binder. The amount of organic solvent used in the present invention results in the composition having a VOC of less thin 0.576 kilogram (4.8 pounds per gallon) and preferably in the range of 0.012 kilogram to 0.576 kilogram (0.1 pound to 4.8 pounds per gallon), more preferably in the range of from 0.12 kilogram to 0.42 kilogram (1.0 to 3.5 pounds per gallon), and most preferably in the range of from 0.012 kilogram to 0.252 kilogram (0.1 to 2.1 pounds per gallon) of organic solvent per liter of the composition. The solids level of the coating of the present invention varies in the range of from 5 percent to 100 percent, preferably in the range of from 10 percent to 95 percent and more, preferably in the range of from 25 percent to 85 percent, all percentages being based on the total weight of the coating composition.
The coating composition typically contains conventional additives, such as pigments, stabilizers, rheology control agents, flow agents, toughening agents, leveling agents, emulsifiers, anti-foaming agents, reducing agents, anti-oxidants, UV-stabilizers, sag control agents and catalysts such as organic carboxylic acids and fillers. Such additional additives will, of course, depend on the intended use of the coating composition. Fillers, pigments, and other additives that would adversely effect the clarity of the cured coating will not be included if the composition is intended to be used as a clear coating. The foregoing additives may be added to either the binder or crosslinking component, or both, depending upon the intended use of the coating composition. Optionally, the composition can also contain a compound, such as an acrylate (co)polymer, cellulose acetopropionate, cellulose acetobutyrate, nitrocellulose, a vinyl polymer, an epoxy resin and/or an xcex1,xcex2-ethylenically unsaturated group-containing compound.
The coating composition can be applied to the substrate in any suitable manner, such as by roller coating, spraying, brushing, sprinkling, flow-coating or dipping. It is preferred that the composition be applied by spraying or roller coating.
In use, the binder and crosslinking components of the coating composition are mixed just prior to use or about 5 to 30 minutes before use to form a pot mix, which has limited pot life, in the range of from 10 minutes to 60 minutes, before it becomes too viscous to permit application through conventional application systems, such as spraying. A layer of the pot mix is typically applied to a substrate by conventional techniques, such as spraying, electrostatic spraying, roller coating, dipping or brushing. The layer of the coating composition then cures under ambient conditions in the range of 10 minutes to 3 hours, preferably in the range of 30 minutes to 60 minutes to form a coating on the substrate having the desired coating properties. It is understood that the actual curing time depends upon the thickness of the applied layer and in the presence or absence of any suitable drying devices, such as fans that assist in continuously flowing air over the coated substrate to accelerate the cure rate. Generally, a layer having a thickness in the range of from 25 microns to 300 microns applied over a metal substrate, such as automotive body, cures in 30 to 60 minutes under ambient conditions and in the absence of any suitable drying devices. If desired, baking the coated substrate at a temperature of about 60xc2x0 C. to 120xc2x0 C. for about 10 minutes to 40 minutes may further accelerate the cure rate. The foregoing baking step is particularly useful under OEM (Original Equipment Manufacture) conditions. Suitable substrates include those of pretreated or non-pretreated metals, wood, synthetic materials, paper or leather. Suitable metals include iron, steel and aluminum.
Measurement of Sandability
To correlate one hour primer-surfacer sanding behavior without fouling the s and paper, we compared the primer-surfacer hardness and sanding behavior to the Persoz hardness measurements (number of pendulum oscillations before the machine stops counting) by utilizing only the crosslinking and binder components of the coating composition. The hardness of the coating was measured with respect to time by using a Persoz Hardness Test (Under ASTM D4366 Test) by using a Persoz Hardness Tester Model No. 5854 supplied by Byk-Mallinckrodt, Wallingford, Conn. It was determined that to obtain good 1 hour sandability in the body shop, the Persoz instrument had to provide values of about xe2x89xa770 oscillations, 2 hours after layer deposition onto steel panels via doctor blade, where the resulting dry film thickness was greater than or equal to 40 microns. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to a method and apparatus for manufacturing a rod of tobacco or the like enclosed by a paper strip, wherein a paper strip is supported and transported by a garniture tape and tobacco is deposited on the paper strip, wherein the tobacco is compressed into a tobacco core and a channel is formed in the tobacco core and wherein the paper strip is closed with its longitudinal edges parts around the compressed tobacco core, and to a cigarette manufactured in accordance with said method.
A cigarette with a channel at the circumference of the cigarette is for example known from Dutch patent 173.017 and French patent 1.349.992. These documents only indicate that there is such a channel in the tobacco rod, wherein it is noted in said first document that the cigarette can be manufactured by an adapted cigarette machine. However, it is not indicated which adaptations are required. Further German "Offenlegungsschriften" 3.435.844 and 3.435.845 describe relatively complicated special cigarette machines for manufacturing a tobacco rod with a central core with low density.
A first object of the invention is to provide a method of the above-mentioned type for forming an open channel at the circumference of the tobacco rod in a relatively simple manner.
A second object of the invention is to provide an apparatus, by which it is possible to apply the method according to the invention by minor technical adaptations on existing cigarette machines.
A further object of the invention is to provide a cigarette manufactured by the method according to the invention. | {
"pile_set_name": "USPTO Backgrounds"
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The use of user equipment (UE) or mobile devices, including smartphones, cellphones, laptops, digital pagers, among others, is becoming more prevalent. Many of these UEs have at least one cellular connection which may be used for both circuit switch and packet switch calls. Such cellular connections are usually based on a subscription or pre-paid plan with a cellular provider.
In order to access the cellular provider's network, a smart card such as a universal integrated circuit card (UICC) is typically found on such devices, where the UICC has one or more applications used for subscriber identity verification. Such applications may, for example, include a subscriber identity module (SIM) application or a universal subscriber identity module (USIM) application for the global system for mobile communication (GSM) networks, for a universal mobile telecommunications system (UMTS system) or long term evolution (LTE) system, a code division multiple access (CDMA) subscriber identity module application (CSIM application) for a CDMA 2000 network, a remote-user identity module (RUIM) for a CDMA network, international mobile services (IMS) subscriber identity module (SIM) for IMS services, among others. Once authenticated to the network, the user equipment may then exchange voice or data, depending on the subscription with the cellular network.
One trend in the workplace is to bring your own device (BYOD) policy for employers, where employees may bring their own device and be connected to enterprise services on that device. However, allocation of resources and billing for such systems is complex, since it is difficult to distinguish between personal and work phone calls, text messages, and data usage and the associated costs and billing between the two. | {
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3rd generation partnership project (3GPP) long term evolution (hereinafter, referred to as ‘LTE’) and LTE-advanced (hereinafter, referred to as ‘LTE-A’) communication systems will be schematically described as examples of mobile communication systems applicable to the present disclosure.
One or more cells exist in one base station. One cell is set to one of bandwidths of 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz with respect to one carrier so as to provide a downlink/uplink transmission service to several user equipments (UEs). In this case, different cells may be set to provide different bandwidths. One base station controls data transmission/reception for a plurality of UEs. The base station transmits downlink (DL) scheduling information of DL data to a corresponding UE so as to inform the corresponding UE of information related to time/frequency domains to which data is to be transmitted, encoding, data size, hybrid automatic repeat request (HARQ), etc. The base station transmits uplink (UL) scheduling information of UL data to the corresponding UE so as to inform the corresponding UE of information related to time/frequency domains that can be used by the corresponding UE, encoding, data size, HARQ, etc. An interface for transmitting user traffic or control traffic may be used between base stations.
Although radio communication technology has been developed up to LTE based on wiideband code division multiple access (WCDMA), the demands and expectations of users and providers continue to increase. Since other radio access technologies have also been continuously developed, new technology evolution is required to secure high competitiveness in the future. The new technology requires decrease in cost per bit, increase in service availability, flexible use of a frequency band, simple structure, open interface, suitable UE power consumption, etc.
Recently, the standardization of the subsequent technology of the LTE is ongoing in the 3GPP. In this specification, the technology is called as ‘LTE-A.’ The LTE and LTE-A systems are different from each other in terms of system bandwidths and introduction of relays.
The LTE-A system aims to support a wideband of a maximum of 100 MHz. To this end, the LTE-A system uses carrier aggregation or bandwidth aggregation technology which achieves the wideband using a plurality of frequency blocks. The carrier aggregation enables the plurality of frequency blocks to be used as one large logical frequency band in order to use a wider frequency band. The bandwidth of each of the frequency blocks may be defined based on the bandwidth of a system block used in the LTE system. Each of the frequency blocks is transmitted using a component carrier.
As the carrier aggregation technology is used in the LTE-A system that is a next-generation communication system, it is required to develop a method in which a UE receives a signal from a base station or relay in a system supporting a plurality of carriers. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates generally to automated machine control, which can be configured for work order management involving multiple agricultural vehicles and crop fields, and in particular to a global navigation satellite system (GNSS) based agricultural spray boom height control system and method.
2. Description of the Related Art
Mobile equipment and machinery, including vehicles, agricultural equipment, open-pit mining machines and crop duster aircraft, are commonly guided and operationally controlled using global navigation satellite system (GNSS) components. Currently-available satellite positioning systems (SATPS) provide parallel and contour swathing for precision farming. For example, equipment can be guided or automatically steered along adjacent parallel path swaths, which can be offset from each other by approximately the vehicle width in a parallel path mode of operation.
Various GNSS-based navigation systems have been installed in ground-based vehicles. Systems using Doppler radar guidance systems can encounter positioning errors with the radar and latency. Similarly, gyroscopes and accelerometers (collectively inertial measurement units (IMUs) provide heading, roll and pitch measurements (e.g., XYZ headings). However, IMUs tend to encounter drift and bias errors requiring external attitude measurements for gyroscope initialization and drift compensation. Gyroscopes have good short-term characteristics but undesirable long-term characteristics, especially lower-cost gyroscopes, such as those based on vibrating resonators.
Similarly, inertial systems employing gyroscopes and accelerometers have good short-term characteristics but also suffer from drift. Existing GNSS position computations may include lag times, which may be especially troublesome when, for example, GNSS velocity is used to derive vehicle heading. Many existing GNSS systems do not provide highly accurate heading information at slower vehicle speeds. Therefore, what is needed is a low cost sensor system to facilitate vehicle swath navigation that makes use of the desirable behaviors of both GNSS and inertial units while eliminating or reducing non-desirable behavior. Specifically, what is needed is a means to employ low-cost gyroscopes (e.g., micro electromechanical (MEM) gyroscopes) which tend to provide good short-term, low-noise, high-accuracy positioning while minimizing inherent long-term drift.
Providing multiple antennas on a vehicle can provide additional benefits by determining an attitude of the vehicle from the GNSS ranging signals received by its antennas, which are constrained on the vehicle at a predetermined spacing. For example, high dynamic roll compensation signals can be output directly to the vehicle steering using GNSS-derived attitude information. Components such as gyroscopes and accelerometers can be eliminated using such techniques. Real-time kinematic (RTK) navigation can be accomplished using relatively economical single frequency L1—only receivers with inputs from at least two antennas mounted in fixed relation on a rover vehicle. Still further, moving baselines can be provided for positioning solutions involving tractors and implements and multi-vehicle GNSS control can be provided.
Providing additional antennas in combination with standard SATPS and GNSS guidance, as mentioned above, along with optional gyroscopes, can provide an effective method to increase GNSS positioning precision and accuracy. However, accuracy and precision can only improve the efficiency of working vehicles, such as those in the agricultural field, to a limited extent. Although such systems are able to track and guide vehicles in three dimensions, including along ridges and sloped-regions, errors may appear in other aspects of a working vehicle. For example, in an agricultural field-working situation where a tractor is towing an implement, the implement may slide on a sloped-region, or the tractor may list to one side or another when entering softer soil or rocky areas. This can happen repeatedly when a vehicle is guided around the same field, regardless of the precision of the guidance system in pre-planning a path. Thus, a system that can detect such changes in uniformity of a field as the vehicle traverses a path, and can remember those changes, can predict and re-route a more accurate and more economical path than a guidance system alone.
Conventional agricultural spraying operations are carried out over an entire field, everywhere the crop is planted. In contrast, environmental spraying allows the spraying of certain materials which require restrictions in the area of deposition due to potential toxicity or strength. The restrictions can include the distance from waterways and slope of the ground which can affect run-off and concentrations of deposits. In spray equipment with booms, maintaining uniform boom height over field surfaces during product application is important for uniform application rates and optimum product drift management relative to the targets, e.g., field crops. These systems are limited in performance due to their ability to look ahead and react with a spray vehicle traveling at a high rate of speed. In addition, these methods encounter issues when there are rapid changes in terrain or skips in crop canopy. The present invention addresses both issues.
GNSS-based precision application of agricultural inputs, such as pesticides, fertilizers and seeds, are commonly performed with large fleets of vehicles dispatched from common or networked home-base locations. Communication of mission planning information to all working vehicles, in real time, is paramount to efficiency. One piece of such information, which is a key to the present invention, is the terrain model, which can be created with specialized software using previously-logged field data containing highly precise positioning information from real-time kinematic (RTK) GNSS receivers. The logged data can be uploaded to the processing center from the logging vehicle through any data connection, although a wireless/remote connection is most desired for efficiency. Once processed, the terrain models can be dispatched from the home-base or processing center location to any vehicle via wireless data connection. The data is thus available to operators preparing to work fields using the boom height control system of the present invention. Using wireless data connectivity, the Internet (i.e., via the “Cloud”) enables efficient use of a boom height invention via the seamless transfer of the terrain model, which is a key component of the system.
Work order management functions for coordinating multiple machines at multiple remote locations can be accommodated with the present invention.
Previous spray boom height control systems include sonic sensors for measuring spray boom heights over ground surfaces and crop canopies.
Heretofore there has not been available a system and method with the advantages and features of the present invention. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to an apparatus for medical X-ray diagnosis and/or X-ray therapy which includes a detection device for electromagnetic detection of the presence of an object in the vicinity of a movable part of the apparatus, and also includes:
at least one sensor electrode which is mounted on the movable part in order to produce an electromagnetic field in the vicinity of this sensor electrode,
at least one sensor electrode which is mounted on the movable part in order to detect an electromagnetic field in the vicinity of this sensor electrode,
a receiver for receiving, via a sensor electrode, an input signal which corresponds to the electromagnetic field in the vicinity of the sensor electrode, and
an additional electrode.
An apparatus of this kind is known from U.S. Pat. No. 5,651,044.
An apparatus for medical diagnosis and/or therapy may be provided with a radiation transmitter and a radiation receiver. An example in this respect is formed by a medical X-ray apparatus which is provided with an X-ray source and an X-ray detector, which is usually referred to as an image intensifier. These two elements are arranged at some distance from one another and the patient to be examined or treated is positioned between the X-ray source and the image intensifier. The X-ray source and the image intensifier are positioned relative to the body of the patient in such a manner that an image can be formed of the desired cross-section of the body (the object). The orientation and the position of such apparatus can often be adjusted by means of a motor drive. Generally speaking, in the context of the present invention an object is to be understood to mean the body of a patient to be examined or another object to be examined, the body or a part of the body of a person operating the apparatus, parts of the apparatus itself (for example, the patient table) or of neighboring apparatus, or other obstacles which could invade the path of movement of the parts of the apparatus.
Many of such apparatus are provided with a so-called C-arm, that is, a circular carrier which is rotatable in its own plane (so about an axis extending perpendicularly to the plane in which the C-arm is situated) by way of a trackway, its own plane being rotatable about an axis situated in said plane. Furthermore, a number of other possibilities of displacement also exist.
During the use of the apparatus it is important that a movable part, for example the image intensifier, closely approaches the object to be examined so that the desired clarity and magnification factor of the image can be attained. The image intensifier has a comparatively large front surface for receiving the X-rays and each point on this front surface or on its circumference could come into contact with the object to be examined. Such a collision can take place in any direction of movement of the image intensifier. This is undesirable and, therefore, such an apparatus is provided with a detection device for the detection of the presence of an object in the vicinity of the movable part of the apparatus. It is important to install such a detection device notably in the case of motor-driven apparatus. When the presence of an object is detected within a given small distance from the movable part of the object, the motion of (said part of) the apparatus can be stopped so as to prevent a collision.
The cited U.S. Pat. No. 5,651,044 discloses a medical X-ray apparatus with a capacitive collision sensor which is capable of detecting the presence of an object within a given distance from the movable part (the image intensifier) of the apparatus. The apparatus is provided with a signal source for producing an electric signal which is applied to a sensor electrode mounted on the outer circumference of the image intensifier. An electromagnetic field is thus produced in the vicinity of this sensor electrode; also connected to the sensor electrode is a signal receiver which receives a signal which corresponds to the electromagnetic field in the vicinity of the sensor electrode. This signal is further processed by means of a processing unit which produces an output signal corresponding to the field strength. This known detection device utilizes the same sensor electrode for the production as well as the detection of the field strength.
The known detection device is also provided with one or more additional electrodes for the electromagnetic shielding of the sensor electrodes for the detection of the presence of other components of the X-ray apparatus, such as the image intensifier itself or the slide on which it moves.
The sensor electrodes of the known detection device are mounted around the X-ray receiving window of the image intensifier. Because the X-ray receiving window of an image intensifier may be comparatively large, particularly at the center of this (often approximately circular) window there are regions which lie outside the sensitive area of the sensor electrodes, so that in these regions the proximity of the object to be examined cannot be detected or only inadequately so.
It is an object of the invention to provide an apparatus of the kind set forth in which the detection of the proximity of an object to be examined is enhanced.
To this end, the apparatus according to the invention is characterized in that
the additional electrode is RF coupled to at least one sensor electrode,
which additional electrode is arranged in the beam path between the X-ray apparatus and in the sensitive area of said sensor electrode, and
which additional electrode includes a carrier of a material which is substantially transparent to X-rays, said carrier supporting a layer of an electrically conductive material of a thickness such that this layer is substantially transparent to X-rays.
The sensitive area of the detection device is expanded by the RF coupling of the additional electrode to the sensor electrode. The arrangement of the additional electrode in the beam path of the apparatus ensures that this electrode covers exactly the region in which a reduction of the intensity occurs in the known apparatus. The original region covered by the sensor electrode remains the same. Because the carrier of the additional electrode and the layer of electrically conductive material are both substantially transparent to X-rays, the additional electrode does not form an obstacle for the X-rays to be detected.
The movable part in a first embodiment of the invention is formed by an X-ray detector whose X-ray receiving side has a substantially cylindrical shape, the sensor electrodes being constructed so as to be strip-shaped and being arranged in a mutual parallel arrangement in the same plane around the cylindrical shape whereas the additional electrode is arranged directly in front of the X-ray receiving side of the X-ray detector. The strip-shaped sensor electrode, or assembly of sensor electrodes, in this embodiment creates a sensitive area which is situated mainly in the vicinity of the edge of the X-ray receiving window of the apparatus; if a plurality of sensor elements are present (for example, separate transmitter and receiver electrodes), they are arranged so as to extend parallel to one another. Because of the strip-like shape of the electrodes, a preferred orientation for the sensitivity is avoided. The additional electrode can be formed as a circular plate which is arranged directly in front of the X-ray receiving window; it should be proportioned such that the edge of this plate very closely approaches the edge of the sensor electrode.
The strip-shaped sensor electrode in a further embodiment of the invention is subdivided into a number of N parts, the additional electrode being subdivided into a corresponding number of N sectors, each of said sectors being situated opposite a respective one of said parts of the detection electrode. This step enables the detection of not only the presence of an obstacle, but also of the position of the obstacle relative to the X-ray detector, for example, by determination of the difference in the strength of the signals from the various sectors. On the basis of said information the direction can be decided in which the apparatus must displace the image intensifier so as to avoid an impending collision.
In another embodiment of the invention the RF coupling between the additional electrode and the sensor electrode is realized without a physical connection. In this embodiment the sensor electrode and the additional electrode must be arranged so near one another that a capacitive coupling is realized between the two types of electrode. Because of the absence of physical electrical connections, the advantage is achieved that no expert personnel is required so as to remove and re-install the additional electrode, for example, in the case of cleaning of the image intensifier.
The carrier in a preferred embodiment of the invention is made of a synthetic material. Because many synthetic materials consist mainly of light elements such as hydrogen and carbon, the required X-ray transparency is achieved by the choice of this carrier material.
The layer of electrically conductive material in a further embodiment consists of aluminium and/or nickel. These materials are comparatively highly transparent to X-rays and can be deposited in such thin layers that the thickness of the layer does not impose a restriction from a point of view of X-ray absorption. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention relates to a new and simplified arrangement of a stuffing box assembly which is discussed herein in particular application to pumps having reciprocating or rotary pump rods but which is also applicable to any situation where an actuating rod or shaft penetrates through a wall and into a chamber containing a fluid, particularly an environmentally hazardous fluid under pressure. The present invention concerns a stuffing box assembly having an internal pressure transmitter piston used to equalize the pressure across the secondary seal in a stuffing box for reciprocating or rotating rods of pumping systems and to transmit the pressure of the fluid being pumped to a sacrificial safe-lubricant so the primary seal will be sealing a fluid of known characteristics. More particularly, the present invention is directed to reciprocating multiplex plunger pump stuffing boxes which include axially spaced primary and secondary seals that are separated by an annular chamber which contains a safe, refined, and clean lubricating fluid, such as a food grade hydraulic fluid. Even more particularly, the present invention concerns a stuffing box assembly having primary and secondary seals within a housing, with a safe lubricating fluid reservoir within the housing and arranged to contain a safe lubricating fluid therein at a pressure slightly exceeding the suction pressure of the pump, so that the secondary seal is substantially hydro-balanced with respect to suction pressure and both the primary and secondary seals are exceptionally well lubricated, thus permitting the packing assembly to have exceptionally long service life and to prevent leakage of pumped fluid to the environment.
2. Description of the Prior Art
One of the greatest sources of pollution of toxic fluids is the result of packing seals leaking when attempting to seal hazardous fluid under pressure. All plunger pumps used to transfer, load, circulate liquids, or produce oil wells with hydraulic pumps have, at one time or another, had to have the packing seal assemblies replaced because of leakage of the fluid being pumped due to wear to or damage of the packing seal assemblies by the pumped fluid. More and more oil wells are being produced with hydraulic pumping systems, and the horsepower requirements increase as the wells get deeper. As the pressure increases, the life of packing seals and pump plungers decreases. The application of this technology to multiplex plunger pumps as used in hydraulic pumping systems for producing oil wells will overcome the universal problem of losing production and polluting the area around the pumping unit.
In recent years progressive cavity pumps (P.C. pumps) have been developed for producing oil wells using rotating sucker rods. In P.C. pumping systems the stuffing box packing seals do not receive any lubrication from the fluid being pumped because the polished rod is rotating in the stuffing box instead of reciprocating, as compared with beam type pumping units, where the polished rod strokes down into the fluid being pumped. The greatest problem and maintenance requirement in P.C. pumping systems is controlling the leakage of produced fluid through the stuffing box seal around the rotating polished rod due to lack of lubrication, causing heat. The present invention helps solve the this problem in P.C. pumping systems, because the packing seals are pressure lubricated with clean refined fluid of known characteristics, and because hydro-balance is provided across the secondary seal. Maintenance cycles are greatly extended and no produced fluid will leak to the environment when the primary packing seal begins to leak.
The concept of hydro-balancing the pressure across the secondary seal of a stuffing box is the subject of U. S. Pat. No. 5,209,495 which is embodied in a commercial product for reciprocating sucker rod pumping systems. However, this patented technology has the pressure transmitter as a separate component of the stuffing box with the transmitter piston functioning in its own housing or cylinder. | {
"pile_set_name": "USPTO Backgrounds"
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A reading control technique is a technique of reading a digital stream recorded on a recording medium such as a BD-ROM at a desired rate, for example, at 4 times or 8 times, and supplying the read digital stream to a decoder.
Generally, a program for realizing this control is stored in a playback device as a built-in program. However, such a control program which is recorded on a BD-ROM and supplied to a playback device will become widespread in a near future, in order to produce a movie with a video stream being played back in conjunction with an application. The producing of the movie work will be described below.
When producing the movie work, an application using video data is recorded on a recording medium having the video data recorded thereon. Upon start-up by a playback device, the application sets a character in motion next to the video data being played on a screen. By making such an application to apply to a game or a quiz, an added value of the movie work will be enhanced greatly.
In such interactive control, adjustment of a video playback rate by the control program on the BD-ROM can speed up or slow down the motion of the character while playing back the video. By recording this control program on the BD-ROM for playback in the playback device, an interactive application in close conjunction with video can be distributed. As a result, the added value of the movie work can be further enhanced. Conventional techniques relating to adjustment of a playback rate include a known technology disclosed in the following Patent Document 1. Patent Document 1: Japanese Patent Application Publication No. 2003-7035 | {
"pile_set_name": "USPTO Backgrounds"
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Heat exchangers are used in various capacities in automotive applications. For example, all automobiles having water cooled engines employ a radiator and a heater core. Automobiles equipped with air conditioning also include an evaporator and a condenser. These heat exchangers are made from aluminum and consist of two spaced header tanks interconnected by flow tubes having cooling fins extending therefrom. Fluid is circulated through the header tanks and flow tubes to effect the necessary temperature drop.
The header tanks, flow tubes, and cooling fins are rigidly attached to one another by brazing. It has been found that this brazing operation can be most efficiently accomplished in a furnace for mass production applications. Further, it has been found that dividing the furnace into varying zones independently controlled to raise the temperature of the workparts to a predetermined level can be utilized to produce improved braze joints. The zones are created by forming a braze furnace housing from a plurality of tubular shell sections arranged in end-to-end fashion with a partition between each shell section. One example of a multi zone furnace may be found in U.S. Pat. No. 3,756,489 to Chartet, issued Sep. 4, 1973.
The prior art is deficient in that, because the temperature between the various shell sections varies from zone to zone, the degree of thermal expansion and contraction varies from zone to zone creating stress fractures which are not adequately anticipated and prevented. Hence, the prior art is deficient in that satisfactory expansion joints are not provided between the various zones. | {
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This invention relates to a multiple compartmented dynamoelectric machine, and particularly a dynamoelectric machine having a main electromagnetic compartment in combination with one or more auxiliary component compartments formed in a self-contained assembly with a single outer main machine frame.
Different dynamoelectric machines, such as rotary electric motors, have a common basic motor construction with significantly different operating specifications adapted to various particular applications. Generally, a rotary electric motor includes a stationary stator unit and a rotating rotor unit. The stator unit is conventionally an annular unit with a cylindrical rotor unit rotatably mounted therein. The stator unit is mounted within a rigid supporting tubular round main frame. Opposite ends of the main frame are closed by end bearing plates or frames which are precisely formed and secured to the round frame to locate a rotor bearing in a precise coincidence with the axis of the opening of the annular stator. The rotor unit includes a supporting shaft journaled within the bearings in the end bearing frames to rotatably support the rotor. The rotor shaft projecting from at least one end bearing frame for coupling to a load device. Different applications and specifications generally require particular controls as well as particular mounting and couplings for adapting the motor to the particular application. Various controls, such as a centrifugal switch current and temperature sensing devices, a terminal board and the like are mounted within an end of the frame, or in a separate control box and coupled to the motor. Centrifugal switches and second devices may be mounted within the motor's frame structure and connected to suitable external controls for controlled energizing of the motor. The external controls may include various manual and automated control units. Other applications may require forced cooling and a fan unit may be mounted separately or within the motor to create an air flow through the motor.
In current practice, electronic controls are available and widely used in controlling of the motors in response to external sense controls. A typical example is a fractional horsepower motor connected to operate ventilating and fan devices and particularly water or liquid motor-pump devices for use in whirlpools, spas, tubs, jet devices and the like. The controls may be made to respond to the surrounding environment, and are normally or advantageously protected from the surrounding environment. The controls however should be conveniently accessible for monitoring and servicing of the control systems. A particularly practical control housing system is disclosed in the co-pending application of James L. King, entitled "Electric Motors Having Integrated Control Housing And Method Of Fabrication", filed on Feb. 6, 1989 with Ser. No. 07/306,887. As more fully disclosed in the above application, the motor structure is formed with a conventional stator and motor. A cup-shaped end cap is secured to the closed end bearing frame of the motor and specially coupled thereto to form a control compartment immediately adjacent to the end frame of the motor. Electronic and other control components are housed in such compartment, preferably by attachment to the end cap. A basically standard motor can then be provided with a custom designed control located within the end compartment. Basic sized end caps can be provided to accommodate different complexities and components required for different control systems.
In addition, applications may require certain specialized motor constructions for adaptation to a load device. For example, motor driven pump units are often constructed with the motor directly mounted to the pump device. The pump motor is preferably a round motor with a smooth continuous exterior surface to establish an attractive as well as attractice unit for use in spas and like devices. Special consideration must be given to any possible leakage of liquid from the pump unit entering into the motor structure. Thus, the electrical winding of a motor will be damaged, if not destroyed, in the presence of unacceptable liquid contact. Further, the mechanical components, such as the bearings and support structure can be adversely affected by liquids, particularly water and the like. A standard motor pump construction includes a drip compartment between the motor components and the pump. The drip compartment is formed by an extension of a standard pump mounting flange structure to which the motor frame is mounted such that any liquid which escapes from the pump unit along the motor shaft connection discharges into the pump drip compartment. Appropriate openings in the drip compartment discharge the liquid and thereby bypass the liquid from the motor.
In many applications, the motor requires a forced ventilation and cooling. A fan may be mounted on and coupled to the either end of the motor shaft within the annular frame and provide forced air flow through the motor.
Motor controls for a pump driven device will have various electronic controls in modern-day practice. For example, motor driven pump units are widely used for pumping of water in whirlpools, spas and other like tubs. The pumping action will vary with time and require different pumping levels. In addition, various safety factors must be considered in view of the danger of operating electrical devices while in a body of water. Generally, the prior art and commercial development retains a rather conventional approach used over the many years of electric rotary motor development wherein the motors are either specially constructed for an application or the load device and is specially constructed to accommodate and receive the basis motor unit. The above identified co-pending application discloses a particularly advantageous control system and one modular construction of and electric motor which permits custom assembly of the motor for various applications and avoids the fabrication of special motor construction for each specification.
There is a need for a modular design incorporating a basic electromagnetic motor structure which can be readily adapted to various motor specifications and applications. The design should permit application to existing commercial loads and application that presently include special housing and mounting frame constructions and the like. | {
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The present invention relates generally to servo mechanisms, and more particularly to a servo mechanism for controlling a means having a controllable member in response to a difference, or an error signal, between a signal indicating the power required of the means and an actual speed or feedback signal thereof.
Conventionally, servo mechanisms comprise only one spool valve means and an actuator having a piston which is operatively connected to a means having a controllable member. The piston is slidably disposed within a housing of the actuator in order to thereby define first and second chambers within the housing. Each chamber is hydraulically connected through the spool valve means to a source of pressurized fluid and a reservoir. The spool valve means thus arranged is associated with an input signal of the required power and an actual or feedback signal of said means having the controllable member. Thus the spool valve means has three positions, namely, a first position wherein each chamber is interrupted from the pressurized fluid source and the reservoir, a second position wherein the first chamber is hydraulically connected to the pressurized fluid source while the second chamber is hydraulically connected to the reservoir, and a third position wherein the first and second chamber are hydraulically connected to the reservoir and the pressurized fluid source, respectively. Thus the piston will be stopped or moved in response to the position of the spool valve means. However, this requires four valving portions of the spool valve means and the relative position between these four valving portions must be formed with high accuracy which of course results in comparatively high manufacturing costs.
In order to obviate the drawbacks mentioned above, further conventional servo mechanisms have been proposed wherein a piston has large and small hydraulic pressure receiving areas. The small receiving area is adapted to be exposed to the first chamber which is always connected to a source of hydraulic fluid, and the large receiving area is adapted to be exposed to the second chamber which is connected through a spool valve means to the fluid source and a reservoir. However, such servo mechanisms still require two valving portions of the spool valve means, and thus such servo mechanisms also require high accuracy in construction and will also be comparatively high in cost.
Another conventional servo mechanism comprises a piston having small and large hydraulic pressure receiving areas which are exposed to a first and a second chamber, respectively. The first chamber is always connected to a source of hydraulic fluid while the second chamber is always connected to the fluid source through means of an orifice and is further connected to a reservoir through a spool or poppet valve means. Due to the orifice interposed between the fluid source and the second chamber, however, the speed by which the hydraulic pressure within the second chamber increases will be delayed, so that movement of the piston will also be delayed. | {
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Solar is becoming increasingly popular in the United States and abroad, but penetration remains relatively low versus the number of homes that could benefit from solar. The price per kilowatt-hour for solar is now competitive with or below that of fossil fuel based utility power in most areas, however, solar largely remains a niche product for those who value saving money, reducing CO2 emissions, and/or people living off the grid.
One factor that may limit the adoption of solar technology is aesthetics. Most residential solar systems are installed as rectangular framed photovoltaic (PV) modules positioned above an existing tile or composite shingle roof. The solar array often only covers a portion of the roof and therefore stands out both in height and material as separate and distinct from the underlying existing roof. This structure is visible even from the street level and over large distances.
Another obstacle to solar adoption in existing homes is the dissonance between the age of the existing roof and the lifespan of a solar system, particularly where the existing roof is made from composite shingles. The expected life of a solar system is at least 25 years, and the expected life of a composite shingle roof ranges from 20 to 50 years, depending on the local climate and quality of materials. At the time a customer is considering going solar, their existing roof may have less remaining lifespan than the expected lifespan of a solar system. So when deciding to go solar, the customer may be presented with the dilemma of having to get a new roof in addition to the solar system, which dramatically increases the cost of going solar.
Accordingly, there is a need to resolve the dissonance between the expected life of the solar system and the remaining life of the roof, that also blends in aesthetically with the complete roof surface, and that does not require the prospective customer to pay for a new roof and a new solar system over that roof. | {
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1. Field of the Invention
This invention relates generally to transmitting voice telephone calls over Internet Protocol (“IP”) based networks.
2. Discussion of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
One of the paramount challenges facing modem wireless telephone systems is the rapid growth of consumer demand for data services, such as Internet access, text messaging, and e-mail. In fact, consumers are demanding greater access to data related services than ever before, and this trend is not likely to change. For example, in the coming years, consumers will likely expect their wireless telephones to provide many, if not all, of the communications features currently provided by computers communicating over wireline, (e.g., video conferencing, picture mail, etc.). Unfortunately, building or upgrading the wireless telecommunications infrastructure is relatively expensive.
Voice over IP (“VoIP”) is one of many recent wireless telephone advances that may challenge the capacity of the existing wireless communication infrastructure. VoIP systems move the routing of audio telephone calls away from conventional circuit switching networks to packets-based systems. One of the advantages of VoIP is that the IP packets that carrying the voice, referred to as VoIP packets, can be routed over a packet-based networks, such as the Internet or a cellular data network. Unlike conventional circuit switching phone systems that employ a constant connection during telephone calls, VoIP systems only send voice data packets across the network as they are needed. For example, VoIP packets are created and transmitted at the moment a user talks but not when the user listens or either end is in silence. As such, networks that employ VoIP systems may be able to support more telephone conversations over the same bandwidth as conventional circuit switched systems.
Employing VoIP systems in wireless network presents additional challenges that ay be not found in wireline VoIP systems. Most VoIP systems combine small pieces f telephone audio with a header, referred to as the “inner header,” that contains network routing for the telephone call and quality of service (QoS) information to create VoIP packets that can travel via the Internet. With wireless VoIP system, however, the VoIP packets also have to traverse through the wireless network, referred to as the Radio Access Network (“RAN”), to reach the Internet. In order to navigate the RAN, the VoIP packets are encapsulated with a second set of headers, known as the “outer header,” that contain network information for the RAN. After the VoIP packet navigates through the RAN to the Internet, the outer header can be removed from the VoIP packet. The VoIP packet may then travel through the Internet to the intended recipient of the telephone call. When the VoIP packet reaches its intended destination, the telephone audio from a plurality of VoIP packets are reformed and the original telephone conversation is reconstructed with a voice decoder.
In a typical VoIP packet, however, the headers may occupy a significant percentage of the overall VoIP packet size—fifty percent or more in some cases. For example, in the IPv4 standard, approximately sixty percent of each VoIP packet is used by the headers. Similarly, in the IPv6 protocol, approximately seventy percent of the total packet size is used by the headers. Using sixty percent or more of each VoIP packet to transmit headers, however, is inefficient. This inefficiency is especially significant in the RAN, because the backhaul bandwidth of the RAN is typically limited. For example, a typical RAN may employ relatively low bandwidth T1 lines to link components together. As such, it would be advantageous to be able to reclaim some percentage of the VoIP packet space occupied by the headers. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to a traction device for performing traction with a rope, and more particularly to a traction device for medical use which is adapted for correcting an affected part of a patient having a fracture in his or her arm, leg, cervical vertebrae or the like by pulling such affected part.
2. Description of the Related Art
As a conventional traction device for medical use, one shown in FIG. 4 which is invented in Holland is known. To operate this traction device, first of all, a rope 2, which is wound around a drum 1 with one end thereof held at the drum 1, is paid out to allow the other end thereof to be attached to, e.g., a foot of a patient. Next, the drum 1 is fixed by tightening a lock handle 3. Thereafter, a spiral spring inside the drum 1 is tightened by rotating a handle 4, whereby the drum 1 is imparted a potential energy for rewinding the rope 2. Traction is thus performed as the rope 2 becomes tense due to the drum 1 being urged by the spiral spring.
In the aforementioned conventional traction device for medical use, in order to rewind the rope 2 onto the drum 1 after a fitting attached to the other end of the rope 2 has been removed from the foot of the patient, an operator is required to hold the rope 2 with his or her hand so that the 2 will be reversely wound around the drum 1 quietly. If the rope 2 is not thus held, the spiral spring inside the drum 1 pulls the rope 2 rapidly back onto the drum 1, making it likely that not only an operator such as a nurse will be exposed to danger, but also the rope 2 will be jammed on the drum 1 so that the traction device is not readily usable for subsequent operations.
It is therefore an object of the present invention to provide a traction device for use in medical therapy which is easy to operate and highly safe, and which allows a traction rope to be rewound an a drum in an orderly way.
In one aspect, the present invention provides a traction device for medical use, which comprises a drum for rewinding a traction rope while holding a tail end of the rope, a casing for rotatably supporting the drum therein, a spring for urging the drum in a direction of rewinding the rope, a rope coupling attached to a head end of the rope paid out from a rope entrance provided in the casing for blocking the pulling in of the head end of the rope, a first gear provided so as to be rotatable integrally and in a manner concentric with the drum, and a rotary damper having a second gear, which is a small reduction gear meshed with the first gear, and being installed inside the casing.
In another aspect, the present invention provides a traction device for medical use, wherein a tension meter for indicating a tension of the rope is interposed between the rope and the rope coupling.
In still another aspect, the present invention provides a traction device for medical use, wherein a roller for guiding the rope and a biasing piece for resiliently biasing the rope onto the roller are provided in the vicinity of the rope entrance provided in the casing.
In still another aspect, the present invention provides a traction device for medical use, wherein the spring is constructed of a spiral spring contained in a hollow portion of the drum, one end of the spiral spring which is located at the center is fixed to a central shaft which is loosely fitted into the drum in a manner concentric with the drum and supported on the casing, the other end of the spiral spring is fixed to an inner circumferential wall portion located in the hollow portion of the drum, and an adjusting member integrally rotatable with the central shaft for adjustably applying an initial load to the spiral spring is releasably attached to the outside of the casing.
In the above-mentioned traction device for medical use, the drum for rewinding the traction rope is coupled to the rotary damper at all times through the second gear, which is a small reduction gear meshed with the first gear that is integrated with the drum, even when the spring urges the drum in the direction of rewinding the rope. As a result, when the rope is removed from the affected part of a patient suffering a fracture, it is not likely to be drawn back onto the drum violently. Hence, the rewinding operation can be performed at such mild speeds as not to expose an operator such as a nurse to danger.
Further, since all components such as the drum and the damper are installed inside the casing, the traction device can be handled with more ease.
When the tension meter is provided between the rope and the rope coupling, the tension meter can constantly monitor the tractive force applied to the affected part of a patient, thereby allowing a desired traction condition to be maintained.
If the roller for guiding the rope and the biasing piece, which is a flat spring-like piece, for resiliently biasing the rope onto the roller are provided in the vicinity of the rope entrance provided in the casing, during the rewinding operation of the rope onto the drum after a therapy with this traction device has been completed, the damper and the reduction mechanism constructed of the gears jointly act to decelerate the rope pulling speed, and further, the additional action of the biasing piece that biases the rope onto the roller prevents the rope from whirling and bouncing. Therefore, the rope can be rewound onto the drum neatly, thereby eliminating such inconvenience that the operator will have difficulty handling the rope during the next operation.
When a spiral spring is used as the spring and is inserted into the drum, and when the adjusting member for applying an initial load to the spiral spring is releasably attached to the outside of the casing, an initial tractive force can be set properly in the order of 10 N (≈1 kgf) in advance, and hence the operator can use the traction device in hospitals in an extremely simple way.
When a ratchet plate is used as the adjusting member and the ratchet plate meshes with the rotary pawl having a spring attached thereto, the initial load can be applied to the spiral spring easily by rotating the ratchet plate intermittently. | {
"pile_set_name": "USPTO Backgrounds"
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Field of the Invention
The present invention relates to a body cover structure for a straddle type vehicle and particularly, to the structure capable of ensuring an arrangement space of a relatively large electrical component.
Description of Related Art
There is disclosed a structure in which, in a two-wheeled motorcycle as an example of straddle type vehicle, a vehicle body cover located in front of driver's legs swells in the lateral direction of a vehicle and an exhaust pipe is arranged in the vehicle body cover. Japanese patent No. 4,294,180 is considered to be a prior art reference.
By the way, in an off road vehicle having a cradle type vehicle body frame, a tank shroud is provided as a vehicle body cover, but there is not provided the body cover which covers an exhaust pipe. However, there may be cases where the off road vehicle is equipped with a fuel injection device, an ABS unit or the like. In this case, also in the off road vehicle, it is desired to have an electric component arranged in front of the driver's legs. Accordingly, it is required that in such off road vehicle, the body cover is formed in an optimum shape which allows the electrical component to be arranged therein. | {
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Prestressed concrete railroad ties are known. These ties include a standard trapezoidal section usually having a broad, lower, and ground facing section of the ties reinforced with pre-stressed tensile elements, cables such as wire or strand. These wires or strands exert a compression force on the concrete of the tie, especially in the lower and ground facing portions of the tie. The ties at an upper and track supporting surface are manufactured with track fastening hardware integrally formed to the tie. Once the tie is placed, the track fastening hardware enables relative rapid rail placement and holds the rail precisely in place during the life of the tie.
When the ties are subjected to service loading--such as where a train passes over the ties--the pre-stressed concrete remains in compression. In what would otherwise be portions of a conventional wooden tie under tension become portions of the pre-stressed concrete tie under reduced--but not eliminated --compression. There results a concrete tie having superior wear characteristics over its wooden counterpart.
Such ties are manufactured in forms which in most cases define the tie dimensions. In all known cases, forms locate with precision the track fastening hardware. Consequently, a review of the manufacture of concrete railroad ties utilizing forms can be instructive.
In a conventional tie forming process, paired deadmen which resist the pre-tensioning force from the cables are located at opposite ends of a casting bed. Since the tie are cast to a mold, the bottom of which is the casting soffit, and are required to be released from the mold, casting occurs with the broad ground facing portion of the tie upwardly exposed and the track supporting upper portion of the tie with its track fastening hardware facing down. This requires the prestressing tie elements, cables, be elevated a distance from the casting soffit which is a further distance from the base of the casting bed, generally the ground.
Supporting elevated cables under high tension from deadmen is not trivial. The steel elements of the ties are high-strength steel usually stressed to 75% of their ultimate strength. Where the steel elements of the ties are supported in the order of over 6" from the ground, the deadmen at either end of the casting soffit must be designed to resist considerable torque relative to the casting bed. This being the case, it is common to firmly anchor pretensioning deadmen in buried and permanent foundations especially constructed to resist torque.
The forms are placed and distributed longitudinally along the casting bed with the pre-tensioning wires passing through the forms at the respective ends of the ties. The forms define in their lower surface, receptacles for the placement of the track fastening hardware. In one common process, form ends are defined by end gate bars. Once the forms are in place, concrete is poured, usually in conjunction with a vibratory force applied to the molds for consolidating the concrete.
When sufficient solidification has occurred--but before complete curing occurs, the gate end bars are removed leaving defined gaps at the tie ends. Once curing is complete, concrete sawing of the tie and tensile elements occurs at the interval defined by the now removed gate end bars. The discrete ties are then collected and shipped.
Having recited a process representative of the prior art, some of the disadvantages of conventional pre-stressed concrete railroad tie construction can be set forth.
First, and because the deadmen at either end of the casting soffit must resist considerable torque, facilities that manufacture concrete railroad ties are generally not portable; most facilities constitute permanent installations with deadmen having elaborate underground foundations which can never be conveniently moved. The concrete ties themselves are not easily shipped; commonly each conventional length tie weighs in the order of 750 pounds.
Second, the forms which mold the ties are expensive. Compounding this problem, changes in either the kind or location of rail fastening hardware requires replacement of the forms. Since such forms are custom made from steel stock, such replacement is expensive. Further, it is commonly required to discretely identify ties--especially as to production "batch". The forms must be modified to enable this identification. Unfortunately, the placement and manner of tie identification most always varies with each tie customer.
Third, where tie lengths change, form lengths likewise must change. When it is remembered that so-called switch ties come in many differing lengths, many forms are required for a single switch installation.
Fourth, combining the capital cost of deadmen and forms with other required accessories, plants for the production of concrete railroad ties are extremely expensive. Construction of a conventional concrete tie fabrication plant has an extremely high capital cost.
Fifth, the forms must be cleaned and maintained. Cleaning is required between each casting cycle. Form maintenance is required as forms age with use. For example, it is well known that forms, especially in the vicinity of the gate end bars, have wear induced gaps with repeating use. The gaps become points of grout leakage. Grout leakage leads to inconsistent strengths in the cast tie product, especially where such leakage occurs adjacent the tensile members of the tie.
Sixth, when the ties are in use, rail seat abrasion can occur. Specifically, a vulnerable point of the tie is adjacent to the tie fastening hardware where relative abrading movement of the rail relative to the tie and track fastening hardware can occur with the dynamic loading applied by passing rail wheels and their supported loads. Since ties are commonly constructed of a single consistent grade of concrete, abrasion at the tie support surface adjacent the rail fastening hardware is a common occurrence.
Attempts have been made to simplify concrete railroad tie construction utilizing slip forms. In Stinton et al. U.S. Pat. No. 4,253,817 entitled CONCRETE RAILROAD TIE CASTING AND HANDLING SYSTEM, molds defining the track support surface and holding the rail fastening hardware are placed in a casting bed and slip forming occurs over the molds. The tie is slip formed in an inverted disposition relative to the molds defining the track supporting surface and holding the hardware.
It is known to use slip forms--at least partially--for the construction of pre-stressed piles or slabs. | {
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The present invention provides an improved pressure swing adsorption (PSA) process capable of delivering high purity and high recovery of a high purity gas, such as argon, from a feed stream. More specifically, the present invention provides an improved process with high recovery for purification of crude argon available from a cryogenic air separation unit. The high recovery enables the present invention to become a complete process without any additional requirement for purification and recycle back to the cryogenic air separation unit.
Currently, oxygen and nitrogen, the two main products of an air separation, can be directly removed from a two-stage cryogenic rectification unit involving a high pressure column and a low pressure column. Argon, which constitutes almost 1% of the feed air, is then enriched in the middle section of the low pressure column. This enriched argon containing about 10 to 12% of argon, 0.1% of nitrogen and the rest of oxygen is fed to the argon low ratio column to produce crude argon containing impurities of about 1 to 5% of oxygen and 1 to 3% of nitrogen. Crude argon is then purified to about 99.999% purity, typically first by catalytic deoxygenation or by a superstaged argon column to remove oxygen, then by rectification in a high ratio column to remove nitrogen.
Catalytic deoxygenation requires the availability of hydrogen, which is not always available and cost effective everywhere in the world. Hydrogen reacts with oxygen to form water, which is then removed from crude argon. Superstaging is another alternative for oxygen removal by adding additional separation stages in the argon column. However, the number of these additional stages could be fairly large, for example, between 115 to about 140, because of the small difference in the relative volatility between oxygen and argon. Furthermore, a high ratio cryogenic column will still be required for additional nitrogen removal if nitrogen is present in the crude argon column.
As compared to the above conventional very elaborate methods of recovering 80 to about 90% argon from air, a PSA process provides a simple and effective alternative for argon purification and recovery. No hydrogen or additional cryogenic stages are required. However, conventional PSA processes suffer from a rather low argon recovery of about 40%. Thus, it is necessary to recycle the PSA waste stream, still containing significant amount of argon, back to the cryogenic air separation unit for additional recovery. Consequently, PSA is much less attractive.
High purity argon is generally produced by purifying crude argon available from an air separation unit. Adsorption is a promising alternative to cryogenic superstaging as disclosed by Bonaquist and Lockett in U.S. Pat. No. 5,440,884 and catalytic deoxygenation as disclosed by Tomita et al. in U.S. Pat. No. 5,783,162.
Jain and Stern in U.S. Pat. No. 5,601,634 and Jain and Andrecovich in AU-A-47537/93 disclose respective cryogenic temperature swing adsorption purification processes. In AU-A-47537/93, the cryogenic TSA is carried out below 150 K in a two layer adsorbent bed. The first layer comprises one or more equilibrium selective adsorbents, such as calcium exchanged type X and A zeolite to preferentially adsorb nitrogen over argon. The second layer comprises one or more rate selective adsorbents, such as CMS and 4A type zeolite, to preferentially adsorb oxygen. Upon completion of adsorption, the bed is regenerated by passing a warm purge gas substantially free of impurities, such as nitrogen and oxygen. This prior art involves low temperature adsorption and argon recycle.
U.S. Pat. No. 5,601,634 discloses a cryogenic TSA process with a liquid-vapor two phase feed. The adsorption bed contains one or more adsorbents selective for nitrogen and/or oxygen at a temperature between the bubble and dew point of the two phase mixture. The advantage of this two phase feed is that any increase in temperature during the adsorption step will evaporate some of the liquid and that the heat of adsorption is offset. This can improve the adsorption capacity. However, because of low operating temperature and the warm purge required, this process is energy relatively intensive.
Nguyen et al. in U.S. Pat. No. 5,730,003, teaches a PSA process for crude argon purification. The process uses oxygen rate or equilibrium selective adsorbent for oxygen removal. In Nguyen et al., the O2 rate selective adsorbents include CMS, clinoptilolite, type A zeolite, and the O2 equilibrium selective adsorbents include adsorbents disclosed by Ramprasad et al. in U.S. Pat. No. 5,294,418. A layer of nitrogen equilibrium selective adsorbent such as CaA and type X zeolite is mentioned for nitrogen removal. The process uses the following cycle steps: feed pressurization, adsorption, cocurrent depressurization, countercurrent blowdown, countercurrent purging and product pressurization. This process does not require low temperature as required by a TSA. However, the argon recovery is low (about 40%) and recycling of desorption gas, during bed regeneration, back to the cryogenic air separation plant is necessary to enhanced argon recovery. This prior art uses a Simplex two bed PSA system.
Kumar et al. in U.S. Pat. No. 4,477,265, discloses a two stage PSA process for argon purification. The two layers of adsorbents for oxygen and nitrogen removal are in two separated stages. The two stages are connected in series. This allows the process to be more flexible, for example, it permits possible bed interactions even within a stage and using different number of beds in different stages. In one preferred embodiment, three beds are in fact used in the first stage for nitrogen removal using a nitrogen equilibrium selective adsorbent. Two beds are in the second stage for oxygen removal using an oxygen rate selective adsorbent. The basic cycle steps include adsorption, evacuation and pressurization. Also, argon recovery is low, and recycling the waste stream, still containing considerable amount of argon, back to cryogenic unit is necessary for additional recovery. In addition, recycling of PSA waste stream back to the cryogenic plant makes the air separation unit more complex and a PSA option less attractive.
Also, Kumar et al. in U.S. Pat. No. 5,395,427 discloses a two stage PSA process using oxygen and nitrogen equilibrium selective adsorbents for producing high purity oxygen from air. The oxygen equilibrium selective adsorbent is a cobalt-based material and preferably used in the second stage. Carbon dioxide, water and nitrogen are preferably removed in the first stage filled with one or more adsorbents selective for the impurities. Oxygen is desorbed from the second stage as product, and the effluent is used to regenerate the first stage adsorbent(s).
Wilson, U.S. Pat. No. 4,359,328, discloses an inverted PSA process, in which a strong component is adsorbed at low pressure while a weak component is adsorbed at high pressure. This is just opposite to conventional PSA process and could be used to recover strong component with enhanced purity.
Lee and Paul, U.S. Pat. No. 5,738,709, discloses a nitrogen PSA process with an intermediate pressure transfer. Instead of a conventional end-to-end (bottom, top or both) transfer, a transfer is carried out from an intermediate point of the high pressure bed to a point close to the feed end of the low pressure bed. Such a transfer increases the productivity and recovery of nitrogen.
Leavitt, U.S. Pat. No. 5,085,674, discloses a Duplex PSA process. The setup is similar to a two stage PSA but with two distinguished features: intermediate feed between the two stages rather than at one end (top or bottom) and recycling capability from the low pressure bed to the high pressure bed. Such a process combines both the conventional PSA and the inverted PSA features of U.S. Pat. No. 4,359,328, and could provide high purity and also recovery. However, this process has not been applied to argon purification with removal of both oxygen and nitrogen. In addition, the process does not advantageously use the capability of the system, e.g., intermediate pressure transfer.
Diagne et al, J. Chem. Eng. Japan, 27, 85 (1994), Ind. Eng. Chem. Res., 34, 3089 (1995), J. Chem. Tech. Biotechnol. 65, 29 (1996), discloses a Duplex process for carbon dioxide removal and enrichment from air-carbon dioxide mixtures. It simultaneously concentrates and removes carbon dioxide beyond the factor of pressure ratio between adsorption and desorption, a limit for the conventional PSA.
Garrett, U.K. Patent No. 2,174,922 A, discloses a fast cycle PSA system for separating a gas feed mixture into two gas streams. The system is close to the Duplex and also has intermediate feed and bottom recycle features. However, the process focuses on fractional pressure change for thermodynamic efficiency and short cycle time. This consequently limits the purity in the separation process. Therefore, it could not be applied to purification where high purity is required as in the instant invention.
The non-PSA processes, i.e., superstaged cryogenic distillation and catalytic deoxygenation, in the prior art of crude argon purification require a large number of cryogenic stages or the availability of hydrogen. In addition, they normally require some recycling between argon purification unit (argon column or deoxygenation system) to the main air separation unit and further residual nitrogen removal. Therefore, the entire hybrid plant from air separation to argon purification becomes very complex, less flexible and less attractive.
On the other hand, conventional PSA processes in the prior art could provide high argon purity, but the recovery is limited. So, a recycling from PSA back to the air separation unit is normally required for additional argon recovery. This in turn makes PSA integration more difficult and less flexible.
The Duplex process of Leavitt in U.S. Patent No. 5,085,674 is able to provide both high purity and recovery by using an intermediate feed and a recycle at the bottom ends between desorption and adsorption beds. In the Leavitt process, argon is purified from its mixture with about 100 ppm nitrogen using 13xc3x97 molecular sieve and operating at 105-210 kPa pressure range and at ambient temperature. However, Leavitt""s Duplex process does not utilize simultaneous removal of oxygen and nitrogen, and thus does not provide a complete argon purification process.
It is an object of the present invention to provide an advanced PSA purification process which is capable of delivering a gas, such as argon, at high purity and high recovery. More specifically, it is an object of the instant invention to provide an improved crude argon purification process which does not require any additional purification or recycling from PSA back to the cryogenic air separation plant for higher argon recovery. In addition, the instant invention is intended to use more efficient process cycle and adsorbents.
In a preferred embodiment, the instant invention preferably provides an improved Duplex process with simultaneous removal of both oxygen and nitrogen. Therefore, it is a complete argon purification process, and there is no need for recycle from PSA to the cryogenic unit. In addition, in a preferred embodiment, the instant invention enhances process performance and economics by using improved adsorbents (e.g., LiX zeolite with SiO2/Al2O3 ratio of 2.0-2.5, CMS and materials disclosed by Ramprasad et al. in U.S. Pat. No. 5,294,418) and process cycle (short cycle time and overlapping steps). Additionally, in a preferred embodiment, the instant invention uses improved bed-to-bed interactions such as dual end pressure transfer.
In a more preferred embodiment, starting with crude argon (e.g., 97.5% Ar, 1.5% O2 and 1% N2) from a cryogenic air separation plant, the instant invention can purify argon to over 99.999% purity and with high recovery over 70% (theoretically as high as 99%) while employing only a Duplex PSA system with no recycle requirement of the argon in the PSA waste stream to the cryogenic air separation unit.
An improved process of this invention is characterized by one or more of the following:
a Duplex PSA system for crude argon purification with simultaneous removal of oxygen and nitrogen;
high purity and recovery of argon product;
a complete purification system: no need for recycle from the PSA to the cryogenic air separation unit and further purification;
use of advanced materials such as nitrogen selective (e.g., LiX) and oxygen equilibrium selective adsorbent (e.g., TEC); and
improved process cycle: overlapping steps, fast cycle and bed-to-bed interaction. | {
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The invention relates to an improved process for the preparation of a copolyether ester. Copolyether esters are thermoplastic elastomer polymers built up of hard polyester segments of repeating units derived from at least one alkylene glycol and at least one aromatic dicarboxylic acid or an ester thereof and soft segments derived from a polyalkylene oxide glycol. Such a copolyether ester is generally prepared by a process involving the combining in the melt of at least one alkylene glycol, at least one aromatic dicarboxylic acid or an ester thereof and the polyalkylene oxide glycol. If an ester of an aromatic dicarboxylic acid is started from, for instance the dimethyl ester of terephthalic acid, then first a transesterification reaction takes place upon which the alkylene glycol and the polyalkylene oxide glycol take the methyl position in the aromatic dicarboxylic acid ester, with the methanol, which is volatile under the transesterification reaction conditions, being separated off. If the aromatic dicarboxylic acid is present in place of the ester, then esterification with the glycols takes place directly. Subsequently, polycondensation of the ester to yield polyester, in the case specified here copolyether ester, takes place under reaction conditions that are generally different from those of the transesterification or esterification. The polycondensation in the melt is then continued until a polycondensate with the desired molecular weight is obtained.
In a number of cases, especially if the polyalkylene oxide glycol is based on propylene oxide, the polycondensate must then be subjected to solid-phase post-condensation in order to achieve a sufficiently high molecular weight. For the softer copolyether esters the polycondensation is also much slower than for the harder copolyether ester that contain less soft segment.
It has proved possible to shorten the time needed to obtain a desired molecular weight in the melt condensation process by using a catalyst. Various catalysts have been developed for this; in practice, complex titanium compounds, in particular titanium tetrabutoxide (TBT), have found the widest application.
In U.S. Pat. No. 3,801,547 A and U.S. Pat. No. 4,687,835 A besides TBT salts of a bivalent metal, in particular magnesium acetate and calcium acetate are used as cocatalysts. In said patent publications other combinations of titanium and magnesium are also mentioned, for instance Mg[HTi(OR6]2 where R=alkyl, and other complex titanates obtained from alkaline earth metal alkoxides and titanate esters. No reasons are given for the use of such combinations of a bivalent metal compound with the titanium compounds. The molar ratio of titanium to bivalent metal is generally 2:1.
In spite of the presence of said catalyst combinations, the state of the art processes take quite some time or lead, as for instance stated in Example 2 of U.S. Pat. No. 3,801,547-A at most to a copolyether ester having a minimum melt flow index (MFI) of 5.1 g/10 min. Polyether esters with such a high MFI can be used for only a limited number of processing techniques.
By using chain branching, for instance by alcohols or acids with a functionality of three or higher, for instance trimethylol propane or trimellitic acid, the time needed to reach a certain molecular weight can be shortened also, or a copolyether ester with a lower MFI can be obtained, see U.S. Pat. No. 4,205,158-A. However, the resulting branched copolyether esters have inferior elastic and fatigue properties, making them less suitable for use in, for instance, bellows in automotive applications under more extreme conditions.
Another process by which the problem of the low reaction rate in the preparation of the softer copolyether ester types can be obviated comprises partial replacement of the terephthalic acid by isophthalic acid, so that a lower polyalkylene oxide segments content is needed for a certain shore D hardness, while the hard segments content, which promotes a higher polycondensation rate, increases. However, this process has the drawback that the melting point of the copolyether ester is substantially lower than that of the corresponding copolyether ester that is based entirely on terephthalic acid, while moreover the glass transition temperature is higher. Particularly in applications at higher temperatures and extremely low temperatures, for instance under the bonnet, these iso- and terephthalic acid based copolyether esters prove less suitable. In addition, the elongation at break is lower.
The aim of the invention was therefore to find a process that offers the advantage of an increased polycondensation rate while it does not have the above-mentioned drawbacks, or only to a very limited extent.
The inventors have now found, very surprisingly, that when the ratio of titanium to bivalent metal in the catalyst combination is chosen to be substantially lower than the value of 2 that has so far been customary, for instance 1.6 or even lower, the polycondensation time for a given viscosity is substantially shortened and it proves possible to produce, without solid-phase post-condensation, copolyether ester that is suitable for, inter alia, injection moulding applications, but contains substantially less chain branching agent, or even no chain branching agent at all, than copolyether esters obtained in the melt according to the state of the art as described in U.S. Pat. No. 4,205,158-A.
The process according to the invention for the preparation of a copolyether ester with hard polyester segments of repeating units derived from at least one alkylene glycol and at least one aromatic dicarboxylic acid and soft segments derived from at least one polyalkylene oxide glycol, which comprises polymerization by polycondensation in the melt of at least one aromatic dicarboxylic acid, at least one alkylene glycol and at least one polyalkylene oxide glycol in the presence of a catalyst based on a combination of titanium and a bivalent metal in a single compound or a combination of titanium and bivalent metal containing compounds, is characterized in that the molecular ratio of titanium to bivalent metal is at most approximately 1.6, preferably at most 1.5.
The best results are achieved when the molecular ratio of titanium to bivalent metal is approximately 1.
Within the group of bivalent metals in particular the alkaline earth metals, for instance magnesium, barium and calcium, and zinc are very suitable. Magnesium is preferred. Preferably, the titanium and the bivalent metal are combined in two separate compounds. The compounds already referred to in the introduction are in principle eligible for use in the process according to the invention. However, the invention is not limited to these.
Preferably, the titanium is used in the form of a metal organic compound, for instance in the form of a titanium alkoxide, for instance TBT, or a titanium ester. The bivalent metal is preferably used in the form of a compound that is soluble in the reaction mixture, for instance in the form of an acetate, preferably magnesium acetate. The concentration of the catalyst in the reaction mixture may vary within broad limits; in general the useful activity is within a range of 0.01 wt. %-1 wt. % of TBT, relative to the terephthalic acid or terephthalate used. Preferably, the content lies between 0.03 and 0.3 wt. % TBT. Below a value of 0.01 wt. % TBT no effect is generally noticeable, and at a content of higher than 1 wt. % a polycondensate is obtained that is unsuitable for solid-phase post-condensation. Generally speaking, in the copolymerization of copolyether esters on the basis of polybutylene oxide diol or polyethylene oxide diol a smaller amount of catalyst will suffice than in the copolymerization of copolyether esters on the basis of polypropylene oxide diol. The same holds for the harder copolyether ester types, for which likewise a smaller amount of catalyst needs to be applied than for the softer types.
The titanium containing compound and the bivalent metal containing compound can simultaneously, or optionally separately, be added to the polycondensation. If an ester of the aromatic dicarboxylic acid is used, for instance the dimethyl ester of terephthalic acid, it is sometimes recommendable to add the bivalent metal containing compound only after the transesterification has taken place. The titanium containing compound can then be added in its entirety already at the start of the transesterification reaction in which methanol is released, or in two steps, viz. at the start of the transesterification and at the start of the polycondensation.
The process for the preparation of copolyether esters can otherwise be applied under the customary conditions for melt polycondensation, with the transesterification reaction taking place at elevated temperature, in general first between 150 and 260xc2x0 C., with methanol being distilled off in case the dimethyl ester of terephthalic acid is used, and subsequently the polycondensation being continued at reduced pressure. The pressure is preferably chosen to be between 0.1 and 30 kPa, and the temperature between 230 and 275xc2x0 C.
The polycondensation will be completed in the shortest time at the lowest pressure. It is also possible to use a dry inert gas atmosphere, for instance nitrogen circulation, instead of reduced pressure. Inclusion of oxygen should be avoided.
If desired, the reaction mixture may contain a minor amount of chain branching agent, However, the process according to the invention has the advantage that much lower concentrations than required in U.S. Pat. No. 4,205,258-A suffice. As chain branching agent use can be made of the compounds mentioned in this patent publication, viz. alcohols having a functionality of at least 3, for instance trimethylol propane, pentaerythritol and 1,1,4,4-tetrakis (hydroxymethyl)-cyclohexane, carboxylic acids having a functionality of at least 3, for instance trimellitic acid, trimesinic acid and 1,1,2,2-ethane tetracarboxylic acid and hydrocarboxylic acids having a functionality of at least 3, for instance citric acid, 3-hydroxyglutaric acid and dihydroxyglutaric acid. Preferably, the functionality is 3 or 4. Preferably, use is made of carboxylic acids having a functionality of 3 or 4, for instance trimellitic acid or an ester thereof and trimellitic anhydride. The chain branching agent content is preferably chosen below 0.3 eq/100 moles of dicarboxylic acid, more preferably below 0.2 eq/100 moles.
The process according to the invention is in principle suitable for the preparation of all types of copolyether esters with hard segments of repeating units, derived from at least one alkylene glycol and at least one aromatic dicarboxylic acid or an ester thereof, and soft segments derived from at least one polyalkylene oxide glycol.
The alkylene group generally contains 2-6 carbon atoms, preferably 2-4 C. Preferred alkylene glycols are ethylene glycol, propylene glycol and butylene glycol. As polyalkylene oxide glycol use can be made, for instance, of polybutylene oxide glycol, polypropylene oxide glycol and polyethylene oxide glycol or combinations thereof, for instance ethylene oxide end capped polypropylene oxide glycol. The invention is effective in particular when the polyalkylene oxide glycol is polypropylene oxide glycol or ethylene oxide end capped polypropylene oxide glycol.
Suitable for use as aromatic dicarboxylic acid are terephthalic acid, 1,4-naphthalene dicarboxylic acid, 4,4xe2x80x2-diphenyl dicarboxylic acid. In particular the combinations of butylene glycol or propylene glycol with terephthalic acid or naphthalene dicarboxylic acid and ethylene glycol with naphthalene dicarboxylic acid and diphenyl dicarboxylic acid (molar ratio 6:4-4:6) are very effective as hard segments for copolyether esters with a high melting point. Optionally, other dicarboxylic acids, such as isophthalic acid, may be present. In general, however, the effect of these is to depress the melting point.
The invention will now be elucidated with reference to the following examples and comparative experiments.
Materials used:
aromatic dicarboxylic acid DMT=dimethyl terephthalate
alkylene glycol BDO=butylene glycol
polyalkylene oxide glycol PL6200=Pluronic PE6200(copyright)=polypropylene oxide end capped with ethylene oxide glycol, from BASF Germany. ethylene oxide:propylene oxide=36:64 (weight ratio) THF 2000=tetrahydrofuran of molecular weight=2000
catalyst TBTxe2x80x94titanium tetrabutoxide MgAc=magnesium acetate tetrahydrate
stabilizer Irganox(copyright) 1330 from Ciba-Geigy, Switzerland.
chain branching agent: TMP=trimethylol propane D-TMD=di-trimethylol propane TMA=trimellitic acid TME-TMA=trimethyl ester of trimellitic acid. | {
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The present invention relates, most generally, to semiconductor devices and methods for forming the same. More particularly, the present invention relates to trench capacitors formed on silicon-on-insulator substrates.
Semiconductor devices typically utilize a multiplicity of capacitors to perform various charge storage functions. Capacitors include two electrodes isolated from each other by an insulating material referred to as a dielectric. Electrodes are commonly formed of conductive or semiconductive materials. According to conventional semiconductor manufacturing methods, capacitors are xe2x80x9cvertically stackedxe2x80x9d and include a horizontally formed dielectric material which insulates conductive or semiconductive materials formed above and below the is dielectric. Materials used as conductive materials include various metals, and materials used as semiconductive materials include doped polysilicon and other films, as well as the silicon substrate itself. The ability of a capacitor to store charge depends on the capacitor area. Since conventional stacked capacitors are formed above the surface of the semiconductor substrate, as the area of the capacitor increases to enhance the charge storage ability of the capacitor, it does so at the expense of substrate surface area which might otherwise be used for other device features. As a result and in order to minimize the surface area occupied by capacitors, trench capacitors have become highly favored in the semiconductor manufacturing industry.
Trench capacitors extend down from the surface of the semiconductor substrate and include a capacitor area which increases as does the depth and width of the trench opening in which the trench capacitor is formed. It can be therefore understood that the charge-storage ability of the capacitor can be increased by simply increasing the depth of the trench and not at the expense of substrate surface area. Trench capacitors are therefore highly favored.
Recent trends in the semiconductor manufacturing industry have been towards the use of silicon-on-insulator (SOI) substrates. SOI substrates are favored because active devices formed within the upper silicon layer, are insulated from the bulk substrate. Therefore, device leakage through the substrate is minimized and other problems associated with being electrically coupled to the substrate, are avoided. The use of SOI technology, however, presents a problem since the trench openings commonly used to form trench capacitors, must extend through the insulating layer of the silicon-on-insulator substrate in order for the trench capacitor to have a sufficient capacitor area. The problem results because the outer of the trench capacitor electrodes is the substrate region which bounds the trench opening. The trench opening is filled with a dielectric liner which insulates the other electrode, commonly a plug formed of a semiconductor material disposed within the trench, from the outer electrode. A shortcoming associated with the use of trench capacitors in SOI technology is that the outer capacitor electrode is insulated from the substrate surface by the insulator film of the silicon-on-insulator substrate structure and cannot be easily contacted. An alternative approach for integrating capacitors into SOI technology would be to revert to stacked capacitors formed above the substrate surface and which include a capacitor area which comes at the expense of device geometry. In these days of advancing device integration, this particular approach is not favored.
The present invention addresses these issues and provides a space saving trench capacitor which is compatible with SOI technology.
The present invention provides a method for forming a semiconductor device including a trench capacitor compatible with SOI technology. The trench capacitor extends through the upper silicon layer and the insulating layer, and extends into the semiconductor base substrate beneath the insulating layer. The trench capacitor includes an inner electrode formed within the trench opening and surrounded by a capacitor dielectric material. The trench capacitor also includes an outer electrode which is electrically coupled to a contact structure formed in close proximity to the trench capacitor. The outer electrode may include portions of the base semiconductor substrate which bound the trench opening, portions of the silicon layer which bound the trench opening, or both.
The method includes forming an associated contact structure in close proximity to the trench capacitor by providing a silicon-on-insulator substrate including a silicon layer formed over an insulating layer formed over a base substrate, forming a duality of trench openings that extend into the base substrate, thermally oxidizing to selectively form an oxide liner on one of the trench openings, and filling each trench opening with a semiconductor material. The contact structure includes a semiconductor material formed in a trench which extends through the insulator material and is thereby electrically coupled to the outer trench electrode which includes portions of the base semiconductor substrate which bound the trench capacitor.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but not restrictive of the invention. | {
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1. Field of the Invention
This invention is related to computer systems and in particular computer systems having integrated circuit computers, serial keyboards, serial displays, and dynamic memories with memory refresh.
2. History of the Prior Art
Prior art data processors typically use magnetic memories such as core memories, thereby precluding a fully integrated circuit computer architecture. Although some prior art computers use integrated circuit memories, these computers use static (non-refreshable) integrated circuit memories; thereby precluding the advantages achievable with a fully integrated circuit computer and with dynamic (refreshable) integrated circuit memories.
Prior art data processors use core memories for program storage and for operand storage. The non-volatile characteristic of core memories, wherein information is preserved when power is removed, permits a program to be stored and preserved in the core memory. The electrically alterable characteristic of core memories permits operands to be stored and modified in the core memory. Such core memories are not producible with monolithic processes as used to manufacture integrated circuits, where the core memory is typically a large, expensive array of discrete elements.
The prior art is further shown in the prior art references cited herein. | {
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An explanation will first be provided of a conventional method of setting a mechanical error correction quantity for mechanical axes which are not orthogonal to each other. FIG. 5(a) shows a grinding tool using a grindstone which moves up and down and which is displayed along a mechanical axis (Z axis) in a direction Z1 with an inclination of, e.g., 45.degree. relative to a horizontal mechanical axis (X axis) on which a workpiece is mounted. A coordinate system (Z1-X1) in the moving directions thereof is referred to as an actual or mechanical axis coordinate system, and thus the terms "mechanical axis" and "actual axis" are used interchangeably herein. However, machining work to be performed by the tool is expressed in terms of an orthogonal coordinate system, and hence a command is issued while (virtually) assuming an orthogonal coordinate system (axes Z2-X1 in FIG. 5(a)). This is referred to as a virtual orthogonal coordinate system. In the conventional system, the Z axis is set as an oblique moving axis for movement in the direction Z1, thereby attempting to obtain improved moving accuracy in the direction Z2 relative to the machining accuracy of the Z axis in the Z2 direction. For example, if it is presumed that the accuracy of the Z axis is 10 .mu.m in the Z1 direction, then the accuracy in the Z1 direction is improved since 10 .mu.m (Z2 direction).div..sqroot.2=7.071 .mu.m (Z1 direction). There is not, however, provided a gauge for measuring a mechanical error with respect to the inclined axis (i.e., Z1 direction). Rather, a gauge is provided for measuring a mechanical error with respect to an axis of the virtual orthogonal coordinate system (i.e., Z2 direction). Specifically, as shown in FIG. 5(a), a gauge 53 of, e.g., 10 mm stands vertically on an X-axis table 52. The mechanical axis Z is located at an origin position (point A). A micrometer provided at the tip of the Z axis is made to contact the gauge, and an indicator of the micrometer is set to 0 at this position. The mechanical axis Z is moved by, for example, 10.times..sqroot.2 mm (10 mm in the virtual orthogonal coordinate system direction Z2) in the direction Z1. The micrometer at the tip of the Z axis contacts the gauge at for example point B, thus reading an error representing the difference between the commanded amount of movement of the tool and the actual amount of movement of the tool. This error is converted by the operator into a mechanical error (gauge value.times..sqroot.2=mechanical error in the direction Z1) and is then set.
FIG. 5(b) shows a known lathe machine tool which comprises a horizontal axis (X axis) along which is disposed a tool 54 and a rotary axis (C axis) on which a workpiece is provided. The X and C axes are axes along which the tool actually moves. These two axes are simultaneously moved, and three axes are controllable by pseudo-creating a Y axis as if performing machining in a Y-axis direction of a machining work orthogonal coordinate system. With this arrangement it is possible to execute complicated machining with a simple construction. There is, however, no means for setting a mechanical error correction quantity for the pseudo Y axis. Hence, a high accuracy encoder 55 is set to the rotary axis, thus measurement-setting the mechanical error at constant angles.
FIG. 3(a) is a block diagram illustrating a conventional control system for effecting a pitch error correction. Referring to FIG. 3(a), the numeral 1 designates a command issued from a numerical control device (hereinafter referred to as a CNC device) to the tool; 2 represents a correction quantity setting means for setting a correction quantity for effecting a pitch error correction with respect to every axis; 4A represents a mechanical axis direction error storage means for storing the correction quantity of each axis set by the correction quantity setting means 2, and 6 represents a command converting means for converting the command 1 to a positional command (a). The positional command (a) is added to the output of the storage means 4A and the added result is output (b) controlling the tool.
FIG. 3(b) is a block diagram depicting a conventional control system for performing a backlash error correction. Referring to FIG. 3(b), the numeral 1 denotes a command issued from the CNC device to the tool; 2 represents a correction quantity setting means for setting the correction quantity for effecting the backlash error correction with respect to every axis; 4A represents a mechanical axis direction mechanical error storage means for storing the correction quantity set in setting means 2; 5 represents a direction reversing means for determining whether or not there is reversal along the mechanical moving axis; and 6 represents a command converting means for converting command 1 into a positional command (a). The stored correction quantity of each axis which is set by the correction quantity setting means 2 is added to each axis command issued to the tool (after the command is converted by converting means 6) and then output (b) to the tool. The mechanical error correction quantity is set with respect to the oblique axis in the same manner as described above in connection with FIG. 3(a) (i.e., the operator performs the conversion).
FIG. 4(a) shows a flowchart for the conventional control process of pitch error correction. Initially, in step 11, it is determined whether or not a command has issued from the CNC device. If it is determined that a command has issued, then it is determined in step 12 whether or not there exists a correction quantity for the axis concerned. If it is determined that the correction quantity is provided, then the correction quantity of each axis is added to the command of each axis (step 18), and the added result becomes an output to the tool. However, if it is determined in step 12 that there is no correction quantity ("N" in step 12), then each axis command is directly output to the tool (step 20).
FIG. 4(b) shows a flowchart for a conventional control process of backlash error correction. In step 11 it is determined whether or not a command has issued from the CNC device. If it is determined that the command has issued, then it is determined in step 12 whether or not there exists a correction quantity for the axis concerned. If it is determined in step 12 that there exists a correction quantity, then it is determined in step 15 whether or not the mechanical moving axis has reversed. During a direction reversion, the correction quantity of each axis is added to the command of each axis, and the added result is output to the tool (step 18). However, if it is determined that there is no correction quantity in step 12, then each axis command is directly output to the tool (step 20). Further, if it is determined in step 15 that there is no direction reversion, then each axis command is directly output to the tool.
The conventional mechanical error corrections (pitch error correction and backlash error correction) are executed in the manner discussed above. Accordingly, the grinding tool (in which the moving axes of the tool are not orthogonal to each other) includes no means for directly measuring the mechanical error of the oblique mechanical axes (e.g., direction Z1 in FIG. 5(a)). Rather, the mechanical error is measured in terms of the orthogonal axes (two or more virtual axes which are orthogonal to each other; e.g., axes Z2-X1 in FIG. 5(a)), and then the mechanical error is converted by the operator into a mechanical error correction quantity in terms of the actual mechanical axes. After this conversion, the mechanical error correction quantity is set. This conversion results in a conversion error. For example, suppose that the mechanical error in the virtual orthogonal coordinate system direction Z2 is 20 .mu.m in FIG. 5(a), and that the error is converted into a mechanical error on the actual mechanical axis Z (direction Z1). This conversion causes the mechanical error to become 20 .mu.m.times..sqroot.2=28.284 .mu.m (.theta.=45.degree.). The converted mechanical error value is then rounded-off resulting in the error value being set at 28 .mu.m. When reconverting this set error value into a mechanical error in terms of the virtual orthogonal coordinate system direction Z2, it follows that the accuracy degrades to 28 .mu.m.div..sqroot.2=19.798 .mu.m. Accordingly, a problem arises in that the grinding tool will not exhibit good accuracy as a result of the conversion error.
Further, there is no means in the conventional systems for setting the correction quantity of the mechanical error of a pseudo Y axis which, as illustrated in FIG. 5(b), is pseudo-created by the rotary axis C and the rectilinear axis X. Hence, a high-accuracy encoder is set at the center of the rotary axis, and the correction quantity is set by measuring the mechanical error at every constant angle. This leads to a problem in that the correction quantity in the vicinity of the center gets rough. For instance, when a correction pitch is set to 5.degree., the accuracy in the vicinity of the center is worse than at the end.
Japanese Patent Laid-Open Publication No. 282863/1987 discloses a method of converting a command expressed in terms of the virtual orthogonal coordinate system into a coordinate system in the mechanical axis direction. According to this method, a machining program expressed in terms of the virtual orthogonal coordinate system is first converted into the coordinate system in the mechanical axis direction, and then the command is given. However, this method is not used in determining the mechanical axis error correction.
Further, Japanese Patent Laid-Open Publication No. 21610/1989 discloses a correction method for an oblique-type tool. This method involves the steps of: inputting a tool diameter, decomposing it into components in the mechanical axis direction, adding the components to a moving distance and performing a pulse distribution. Accordingly, this method is not used as a correcting method for effecting the mechanical error correction on the mechanical axis (Z axis). | {
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The present invention relates in general to an email system for sending electronic messages over computer networks, and more specifically to an email system utilizing proxy email addresses to identify particular email relationships between the sender and recipient.
Conventional email systems are known. These systems operate on the assumption that each user of the email system has a private email address and all mail to be directed to an individual is addressed to this email address. This architecture, however, makes it difficult for an email recipient to organize incoming email messages into subject or organizational categories. Since all email for an individual is directed to a single email address, there is no way to automatically filter the mail unless the sender manually incorporates an identifier into the email message or header. The success of this method is thus dependent upon the response of the sender. A failure to manually include the requisite information defeats the intended functionality.
It is also an important security issue in the operation of an email system that the stated sender of the email message is the actual sender of the email. Any ability to xe2x80x9cspoofxe2x80x9d or disguise the sender compromises the integrity of the email system, which may have severe consequences. It is thus very desirable to eliminate or at least minimize any ability to present a false sender email address to a recipient.
It is also inherent in the conventional email architecture that the sender must know and provide the recipient""s private email address in order to send a message. Typically, for practical reasons the email address of a recipient is not necessarily intuitive, and may require the sender to look up the address in a directory. This, of course, requires an additional effort by the sender to send email, and it would be desirable to avoid any such necessity.
It would thus be desirable to provide an email system that facilitates the automatic filtering of email messages for a recipient so that the recipient can readily organize them according to a desired grouping. Furthermore, access to a recipient""s email mailbox could be denied if the sender did not adhere to the predetermined groupings of the recipient.
It would be further desirable to provide a convenient interface for sending email to a recipient without requiring specific knowledge of the recipient""s private email address.
The present invention advantageously provides for an email system that implements proxy email addresses to control access to a recipient""s email mailbox, and eliminates the requirement of a sender of email to know the recipient""s private email address when sending mail.
In one aspect of the invention, a user interface is presented to a user of the email system that corresponds to permissible email exchanges. The user interface that is presented may be particular to the individual user. The user interface may represent a defined relationship between the email participants identified in the user interface. Email recipients may be included in multiple, user interfaces corresponding to different roles an individual may hold. For example, the user interface may be implemented in a hierarchical tree structure that identifies all the members of a work project, and facilitates email exchanges between the members of the project. Since the project members of one project may also be members of a second project, these individuals will be included in two user interfaces or two hierarchical trees for sending email to other project members.
In a further aspect of the invention, email exchanges are performed through a proxy email address to identify the recipient of the email. The proxy email address corresponds to the particular user interface that identifies the email exchange, and may be different for different user interfaces.
In a yet further aspect of the invention, the proxy email address is converted to the recipient""s private email address prior to delivering the email message to the recipient. Additional information may be added to the email message by the email system that is related to the proxy address used to initiate the email exchange. The additional information related to the proxy email address provides an indication to the recipient of the email""s subject or general focus.
In a still further aspect of the invention, the email system may substitute a proxy email address as the return address for a sender of email in order to identify the subject matter or focus of the reply.
In a further aspect of the invention, the ability to exchange email relating to a certain matter may be eliminated by deleting the proxy email address, and thus the invention provides a convenient and efficient manner of restricting the email exchange process.
In a yet further aspect of the invention, the security of the sender and recipient email addresses is enhanced since the email system generates the sender and recipient email addresses, and thus minimizes the ability to xe2x80x9cspoofxe2x80x9d or present a false email address to the recipient | {
"pile_set_name": "USPTO Backgrounds"
} |
A user device may include a display allowing a user to view a wide variety of content items which may be based on different data types. The display may show information in the form of text, images, graphic objects, bitmaps, video, audio controls, etc. The display may also provide graphic objects which can serve as Graphical User Interface (GUI) widgets permitting user content interaction and control. However, conventional approaches for displaying and controlling content in a simple, accessible manner can present challenges as the number of content options increase and/or the display sizes become limited to sizes consistent with mobile devices. Conventional user interfaces may include formats such as nested menus that may require a user to “drill down” through multiple menus to make a selection. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Technical Field
The present disclosure relates to communication technologies and, particularly, to a photoelectric conversion device and an optical fiber coupling connector.
2. Description of Related Art
An optical fiber coupling connector includes a photoelectric conversion device and a number of optical fibers. The photoelectric conversion device includes a circuit board, a number of light emitting modules, a number of light receiving modules, and an optical coupling lens part. The light emitting modules and the light receiving modules are mounted on the circuit board. The optical fibers correspond to and are optically coupled with the light emitting modules and the light receiving modules one-to-one through the optical coupling lens part. The optical coupling lens part includes a number of first converging portions and a number of second converging portions corresponding to the first converging portions. The optical coupling lens is fixedly mounted on the circuit board. The first converging portions are aligned with the light emitting modules and the light receiving modules. The second converging portions are aligned with the optical fibers.
The optical coupling lens part is fixed on the circuit board via dispensing glue at joint between sidewalls of the optical coupling lens part and the circuit board. On the one hand, the glue occupies much extra space of the circuit board. On the other hand, the optical coupling lens part is easily shifted or dropped from the circuit board when in transit because the contact area between the optical coupling lens part and the circuit board is limited.
Therefore, it is desirable to provide a photoelectric conversion device and an optical fiber coupling connector having the photoelectric conversion device, which can overcome or alleviate the above-mentioned problems. | {
"pile_set_name": "USPTO Backgrounds"
} |
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