There is provided an exhaust apparatus for connection to a personal protection respiratory device that defines a filtered air volume adjacent to the face of a wearer and comprises at least one exhalation, the apparatus comprising a blower in fluid connection with the at least one exhalation valve, the blower being responsive to the wearer's respiratory cycle to draw a substantial portion of the wearer's exhaled breath through the at least one exhalation valve wherein, in response to the wearer's respiratory cycle, the blower operates throughout the wearer's exhale breath, or a substantial period thereof, and does not operate throughout the wearer's inhale breath, or a substantial period thereof.

Negative pressure respirators are well known in the art. With respirators of this type, filtered air is drawn into the enclosed space between the inside of the respirator and a wearer's face through a filter system by the wearer's breathing action. When the wearer draws a breath, negative pressure is created in the respirator and air is drawn in through the filter system. When the wearer exhales a breath, spent air leaves the respirator through an exhalation valve and/or back through the filter system.
Although negative pressure respirators are available in many different configurations, and offer many different benefits, they all have one major drawback, that of the uncomfortable build-up of heat and moisture that can sometimes occur inside the respirator. The heat and moisture build-up is caused by the trapping of the wearer's exhaled breath in the cavity created between the respirator and the wearer's face. As the wearer works harder, and/or wears the respirator for extended periods of time, heat and moisture build-up may increase.
Many different solutions have been proposed in the prior art to eliminate, or at least minimise, the problem of heat and moisture build-up inside negative pressure respirators. For example, the addition of exhalation valves, and optimising the operation of these exhalation valves. The design and optimisation of low pressure drop filters and media has also been proposed to alleviate this problem and/or by controlling the filter surface area and filter material pressure drop. Another solution in the prior art is to include pads to absorb the moisture.
A further solution is offered in WO2014/081788 in which a respirator has a blower in fluid connection with the exhalation valve, the blower being operable to draw the wearer's exhaled breath through the valve. This solution presents advantages but also has drawbacks in that the blower applies a constant negative pressure to the exhale valve. This can lead to increased inhalation effort and decreased filter life as a result of the increased flow of air passing through the filter.
A known improvement to the device of WO2014/081788 is to control the blower so that the blower so that the blower preferably only operates during the exhale breath. This has the advantage that the user no longer needs to overcome the blower during the inhale stroke. Whilst this reduces the inhalatory effort over known devices, the user must still overcome the pressure drop delivered by the filter medium. This can be significant dependent on the type of filter in use and the extent of the respiratory effort of the user.
It is therefore an object of the disclosure to deliver the improved cooling effects of the prior art device whilst reducing the inhalation effort required to overcome the filter pressure drop.
Accordingly, a first aspect of the present disclosure provides an exhaust apparatus for connection to a personal protection respiratory device that defines a filtered air volume adjacent to the face of a wearer and comprises at least one exhalation valve and at least one inhalation valve, the apparatus comprising:
a first air duct in fluid connection with the at least one exhalation valve,
a second air duct in fluid connection with the at least one inhalation valve,
a blower assembly for selectively directing air through the first and second ducts
the blower assembly being responsive to the wearer's respiratory cycle so that, in use,
the blower draws a substantial portion of the wearer's exhaled breath through the first duct and out through the at least one exhalation valve, and
the blower draws a substantial portion of the wearer's inhaled breath through the second duct and in through the at least one inhalation valve.
Operating the blower selectively to draw air through the exhalation valve during user exhalation or draw air through the inhalation valve during user inhalation (or a substantial part thereof) delivers significant advantages to the present disclosure as follows.
Firstly, the inhalation effort of the user is reduced since the pressure drop generated by the filter is at least in part, but potentially entirely, compensated by the blower. In the prior art device the user must generate sufficient back pressure to overcome the filter pressure drop before any air flow passes through the filter. This additional pressure must be maintained throughout the inhalation in order for the user to draw sufficient air into the lung cavity to meet physiological demand. This is not the case in the present disclosure where the blower overcomes the pressure enabling the user to breath "normally", that is to say breath as if the filter was not present in the air flow path to the lungs. This is a significant advantage where heavy duty filters with a significant pressure drop are required.
Secondly, it is possible to operate the blower so as to achieve a positive pressure in the filtered air volume when averaged over the respiratory cycle. This reduces the risk of the filtered air volume becoming compromised by leakage of ambient air between the filter and the user's face during use. This increases the efficacy of the respiratory device.
Preferably, the blower assembly comprises
a first blower associated with the first air duct, and
a second blower associated with the second air duct,
the first and second blowers being responsive to the wearer's respiratory cycle, wherein
the first blower operates throughout the wearer's exhale breath, or a substantial period thereof, and does not operate throughout the wearer's inhale breath, or a substantial period thereof, and
the second blower operates throughout the wearer's inhale breath, or a substantial period thereof, and does not operate throughout the wearer's exhale breath, or a substantial period thereof.
Preferably, the exhaust apparatus further comprises
a controller,
a sensor for sensing a parameter generated by the wearer's breathing cycle and sending a signal indicative of the parameter to the controller,
the controller being in communication with the sensor and the first and second blower,
wherein the controller operates the first and second blower in response to the signal.
Preferably, the parameter is pressure, the sensor is a pressure sensor and the signal is a pressure signal.
Preferably, the pressure is sensed in a filtered air volume of the personal protection respiratory device.
Alternatively, the pressure is sensed downstream of the exhalation valve or upstream of the inhalation valve.
Preferably, the controller stops the first and starts the second blower when the pressure sensed by the pressure sensor falls below a second predetermined pressure or the rate of change of pressure reaches a second predetermined rate.
Preferably, the controller stops the first and starts the second blower when the pressure sensed by the pressure sensor falls below a second predetermined pressure or the rate of change of pressure reaches a second predetermined rate.
Preferably, the first predetermined pressure and the second predetermined pressure are a common predetermined pressure.
Preferably, the common predetermined pressure is substantially ambient pressure so that the controller starts the first blower and stops the second blower substantially at the initiation of the wearer's exhale breath and stops the first blower and starts the second blower substantially at the end of the wearer's exhale breath.
Alternatively, the common predetermined pressure is higher than ambient pressure so that the controller starts the first blower and stops the second blower momentarily after the initiation of the wearer's exhale breath and stops the first blower and starts the second blower momentarily before the end of the wearer's exhale breath.
Alternatively, the common predetermined pressure is lower than ambient pressure so that the controller starts the first blower and stops the second blower momentarily before the initiation of the wearer's exhale breath and stops the first blower and starts the second blower momentarily after the end of the wearer's exhale breath.
Alternatively, the first predetermined pressure is greater than the second predetermined pressure so that the controller starts the first blower and stops the second blower momentarily after the initiation of the wearer's exhale breath and stops the first blower and starts the second blower momentarily after the end of the wearer's exhale breath.
Preferably, the second predetermined pressure is greater than the first predetermined pressure so that the controller starts the first blower and stops the second blower momentarily before the initiation of the wearer's exhale breath and stops the first blower and starts the second blower momentarily before the end of the wearer's exhale breath.
Preferably, the first and second blowers further comprise an inlet, a motor, a fan, and an outlet.
Preferably, the personal protection respiratory device is selected from a group consisting of disposable, reusable, half mask, full face, particulate, gas and vapour and tight-fitting hood respirators.

Powered apparatus for a personal protection respiratory device


Systems, devices, and methods for generating an image representation obtain a set of low-level features from an image; generate a high-dimensional generative representation of the low-level features; generate a lower-dimensional representation of the low-level features based on the high-dimensional generative representation of the low-level features; generate classifier scores based on classifiers and on one or more of the high-dimensional generative representation and the lower-dimensional representation, wherein each classifier uses the one or more of the high-dimensional generative representation and the lower-dimensional representation as an input, and wherein each classifier is associated with a respective label; and generate a combined representation for the image based on the classifier scores and the lower-dimensional representation.

1. Technical Field
This description generally relates to visual analysis of images.
2. Background
In the field of image analysis, images are often converted to representations. A representation is often more compact than an entire image, and comparing representations is often easier than comparing entire images. Representations can describe various image features, for example scale-invariant feature transform (SIFT) features, speeded up robust (SURF) features, local binary patterns (LBP), color histogram (GIST), and histogram of oriented gradients (HOG) features. Representations include Fisher vectors and bag-of-visual features (BOV).

Devices, systems, and methods for learning a discriminant image representation


Epoxy resin compositions that generate reduced levels of sulfur dioxide and which unexpectedly have reduced self-extinguishing times. The epoxy resins are composed of from 50 to 70 weight percent of an epoxy resin component. The epoxy resin composition also includes from 15 to 35 weight percent of a thermoplastic blend that is composed of polyetherimide and polyamideimide. The epoxy resin composition further includes from 5 to 25 weight percent of a curative agent.

1. Field of the Invention
The present invention relates generally to epoxy resins and the properties of such resin when they are burned. More particularly, the present invention involves improving the burn properties of high performance epoxy resins by reducing the amount of sulfur-containing compounds that are emitted when such resins are burned and by also reducing the time it takes the epoxy resin to self-extinguish once it begins to burn.
2. Description of Related Art
Epoxy resins that are reinforced with a fibrous material, such as glass or carbon fiber, are used in a wide variety of situations where high structural strength and low-weight are required. Composite materials that use a high performance epoxy resin matrix are especially popular in the aerospace industry where weight and structural strength are important engineering and design considerations. High performance epoxy resins typically include one or more thermoplastic materials that provide "toughening" of the epoxy resin. Although such high performance epoxy resin composite materials are desirable because of their relatively high strength to weight ratio, they do present some specific issues with respect to flammability, toxic emissions and other burn properties.
High performance epoxy resins of the type that are used in the aerospace industry are generally cured at temperatures of about 177° C. These high performance epoxy resins typically include thermoplastic tougheners and curing agents that contain sulfur. These types of epoxy resins tend to generate toxic sulfur-containing gases when they are burned. The generation of toxic gas is of particular concern when epoxy resin composite parts are located in the interior of aircraft or other aerospace vehicles. A major goal in developing formulations for such high performance epoxy resins is to limit the amount of sulfur emissions that are produced upon burning, while at the same time not reducing the structural strength of the cured composite part. It is also important that any attempt to reduce sulfur emissions does not adversely affect properties of the uncured epoxy resin, such as tack and viscosity. The tack and viscosity of the uncured resin are especially important when the epoxy resin is used to make prepreg, which is a common intermediate material used in the fabrication of aerospace parts.
Resistance to surface flammability is also an important area of concern for high performance epoxy resins. It is important that an epoxy resin composite part, which is on fire, be able to self-extinguish once the source of heat and/or flame is removed. It is also a significant goal of epoxy resin formulators to develop epoxy resins that are self-extinguishing in as short a time period as possible, while at the same time keeping structural strength of the finished composite part at the levels needed for aerospace applications. The same requirement that the tack and viscosity of the uncured epoxy resin not be adversely affected applies with respect to attempts to formulate epoxy resins with low self-extinguishing times.
Sulfur, which is principally in the form of sulfur dioxide (SO2), is a toxic compound that is emitted when a high performance epoxy resin part burns. The National Bureau of Standards (NBS) Smoke Density Chamber is a standard combustion test system that is used to measure SO2 emissions, as well as emission levels of carbon monoxide (CO), hydrogen cyanide (HCN) and nitrogen oxides (NOx). The SO2 emission level is determined by measuring the amount of SO2 in parts per million (ppm) that is released by a sample during combustion under specified thermal exposure conditions in the NBS Smoke Density Chamber.
The specific combustion parameters that are used for measuring the SO2 emission levels of high performance epoxy resin composite materials are set forth in BOEING Specification Support Standard BSS-7238 (Revision B) and BSS-7239 (Revision A), which is recognized in the aerospace industry as a standard test method. The SO2 emission levels for a typical high performance epoxy resin that contains polyether sulfone (PES) or other sulfur-containing thermoplastic toughener will be over 100 ppm. An exemplary PES-toughened high performance epoxy resin is HexPly® resin 8552, which is available from Hexcel Corporation (Dublin, Calif.). It would be desirable to provide epoxy resin formulations where the SO2 levels are 100 ppm or lower.
The United States Federal Aviation Administration has established regulations and requirements for fire resistance of aircraft interior parts and materials. These requirements are set forth in FAR Part 25, Appendix F, Part 1. One requirement is that the material be able to self-extinguish once the flame source is removed. The test procedure for measuring the self-extinguishing time for epoxy resins are set forth in the FAA Aircraft Materials Fire Test Handbook and in BOEING Specification Support Standard BSS-7230 (Revision H), which is recognized in the aerospace industry as a standard test method. A modified version of Method F of BSS-7230 (Revision H) involves igniting a vertically oriented sample of cured neat resin by exposing it to an ignition source for 10 seconds and then measuring the time it takes for the sample to self extinguish. It would be desirable to provide high performance epoxy resin compositions where the self-extinguishing times are as short as possible.

This patent is subject to a terminal disclaimer.

Epoxy resins with improved burn properties


High resolution digital delay circuits and methods are provided. A multiplexer receives the outputs of first and second delay elements. At least the second delay element is adjustable using a digital control signal. The multiplexer and the first delay element form a first delay loop. The multiplexer, the first delay element and the second delay element form a second delay loop. A logic circuit monitors the number of times (M) that a signal cycles through the first loop. After M reaches a predetermined value (i.e., when the signal is delayed by a predetermined delay), the multiplexer receives a control signal that causes the second loop to close. A signal cycles through the second loop, which provides additional delay. Preferably, the signal cycles through the second loop only once. Generally, this causes the resolution of the delay circuit to be proportional to the minimum delay adjustment of the second delay element.

This invention relates to digital delay circuits. More particularly, this invention relates to high resolution digital delay circuits for phase-locked loops (PLLs) and delay-locked loops (DLLs).
PLLs and DLLs are widely used in many applications. Typically, PLLs and DLLs output one or more clock signals locked to both the phase and frequency of a reference clock. PLLs and DLLs lock the output clock to the reference clock by adjusting the time delay of an associated delay circuit. PLLs and DLLs may be used in dynamic random access memory (DRAM) applications to, for example, synchronize DRAM reads, writes and refreshes to a reference clock.
Conventional analog PLLs and DLLs use a plurality of analog voltage-controlled delay elements (VCDs) to lock the output clock to the reference clock. The time delays generated by the VCDs are adjustable and can be controlled by adjusting a control voltage. It is well known that analog designs are more difficult to mass produce reliably with stated specifications and are less portable to various process technologies than digital designs.
Conventional digital PLLs and DLLs use a plurality of serially-connected digital delay elements to lock the output clock to the reference clock. While the time delays of the digital delay elements are adjustable, in present art all of the delay elements are controlled simultaneously by the same digital control signal. In other words, the time delay of one delay element in the serially-connected chain cannot be adjusted without simultaneously adjusting the time delays of all other delay elements in the chain. This causes conventional digital delay circuits to have low resolution.
In general, higher resolution delay circuits (i.e., delay circuits that provide smaller minimum delay adjustments) allow associated PLLs and DLLs to more accurately lock the output clock to the reference clock. Higher resolution delay circuits also allow the associated PLLs and DLLs to more accurately maintain the locked condition in response to process, voltage and temperature (PVT) variations.
In view of the foregoing, it would be desirable to provide high resolution digital delay circuits.

High resolution digital delay circuit for PLL and DLL


A system for writing to a cache memory which eliminates the need, in certain circumstances, to set a dirty bit. The dirty bit indicates that the line of data in the cache has been updated but the corresponding data in main memory has not been updated. Setting the dirty bit can increase the time needed for a bus cycle. When a line of data is written to a cache memory, a dirty bit is set for that line of data. If the next bus cycle is a write to the cache for the same line of data, the cache controller can save time by not setting the dirty bit because the cache controller knows that the dirty bit has been previously set.

1. Field of the Invention
The present invention is directed to a system for using a dirty bit in a cache memory.
2. Description of the Related Art
In a typical IBM PC/AT-compatible computer system, a host processing unit is coupled to a host bus and most I/O peripheral devices are coupled to a separate I/O bus. The host processing unit typically comprises an Intel i386, i486 or Pentium.TM. microprocessor, and the I/O bus typically conforms to a standard known as ISA (Industry Standard Architecture). I/O interface circuitry, which usually comprises one or more chips in a "core logic chip set", provides an interface between the two buses. A typical system also includes a memory subsystem, which usually comprises a large array of DRAMs and perhaps a cache memory.
General information on the various forms of IBM PC AT-compatible computers can be found in IBM, "Technical Reference, Personal Computer AT" (1985), in Sanchez, "IBM Microcomputers: A Programmer's Handbook" (McGraw-Hill: 1990), in MicroDesign Resources, "PC Chip Sets" (1992), and in Solari, "AT Bus Design" (San Diego: Annabooks, 1990). See also the various data books and data sheets published by Intel Corporation concerning the structure and use of the 80.times.86 family of microprocessors, including Intel Corp., "Pentium.TM. Processor", Preliminary Data Sheet (1993); Intel Corp., "Pentium.TM. Processor User's Manual" (1994); "i486 Microprocessor Hardware Reference Manual", published by Intel Corporation, copyright date 1990, "386 SX Microprocessor", data sheet, published by Intel Corporation (1990), and "386 DX Microprocessor", data sheet, published by Intel Corporation (1990). In addition, a typical core logic chipset includes the OPTi 82C802G and either the 82C601 or 82C602, all incorporated herein by reference. The 82C802G is described in OPTi, Inc., "OPTi PC/AT Single Chip 82C802G Data Book", Version 1.2a (Dec. 1, 1993), and the 82C601 and 82C602 are described in OPTi, Inc., "PC/AT Data Buffer Chips, Preliminary, 82C601/82C602 Data Book", Version 1.0e (Oct. 10, 1993). All the above references are incorporated herein by reference.
Many IBM PC AT-compatible computers today include one, and usually two, levels of cache memory. A cache memory is a high-speed memory that is positioned between a microprocessor and main memory in a computer system in order to improve system performance. Cache memories (or caches) store copies of portions of main memory data that are actively being used by the central processing unit (CPU) while a program is running. Since the access time of a cache can be faster than that of main memory, the overall access time can be reduced. Descriptions of various uses of and methods of employing caches appear in the following articles: Kaplan, "Cache-based Computer Systems," Computer, 3/73 at 30-36; Rhodes, "Caches Keep Main Memories From Slowing Down Fast CPUs," Electronic Design, Jan. 21, 1982, at 179; Strecker, "Cache Memories for PDP-11 Family Computers," in Bell, "Computer Engineering" (Digital Press), at 263-67, all incorporated herein by reference. See also the description at pp. 6-1 through 6-11 of the "i486 Processor Hardware Reference Manual" incorporated above.
Many microprocessor-based systems implement a "direct mapped" cache memory. In general, a direct mapped cache memory comprises a high speed data Random Access Memory (RAM) and a parallel high speed tag RAM. The RAM address of each line in the data cache is the same as the low-order portion of the main memory line address to which the entry corresponds, the high-order portion of the main memory address being stored in the tag RAM. Thus, if main memory is thought of as 2'" blocks of 2" "lines" of one or more bytes each, the i'th line in the cache data RAM will be a copy of the i'th line of one of the 2'" in blocks in main memory. The identity of the main memory block that the line came from is stored in the i'th location in the tag RAM.
When a CPU requests data from memory, the low-order portion of the line address is supplied as an address to both the cache data and cache tag RAMs. The tag for the selected cache entry is compared with the high-order portion of the CPU's address and, if it matches, then a "cache hit" is indicated and the data from the cache data RAM is enabled onto a data bus of the system. If the tag does not match the high-order portion of the CPU's address, or the tag data is invalid, then a "cache miss" is indicated and the data is fetched from main memory. It is also placed in the cache for potential future use, overwriting the previous entry. Typically, an entire line is read from main memory and placed in the cache on a cache miss, even if only a byte is requested. On a data write from the CPU, either the cache or main memory or both may be updated.
Accordingly, in a direct mapped cache, each "line" of secondary memory can be mapped to one and only one line in the cache. In a "fully associative" cache, a particular line of secondary memory may be mapped to any of the lines in the cache; in this case, in a cacheable access, all of the tags must be compared to the address in order to determine whether a cache hit or miss has occurred. "K-way set associative" cache architectures also exist which represent a compromise between direct mapped caches and fully associative caches. In a k-way set associative cache architecture, each line of secondary memory may be mapped to any of k lines in the cache. In this case, k tags must be compared to the address during a cacheable secondary memory access in order to determine whether a cache hit or miss has occurred. Caches may also be "sector buffered" or "sub-block" type caches, in which several cache data lines, each with its own valid bit, correspond to a single cache tag RAM entry.
When the CPU executes instructions that modify the contents of the cache, these modifications must also be made in the main memory or the data in main memory will become "stale." There are two conventional techniques for keeping the contents of the main memory consistent with that of the cache--(1) the write-through method and (2) the write-back or copy-back method. In the write-through method, on a cache write hit, data is written to the main memory immediately after or while data is written into the cache. This enables the contents of the main memory always to be valid and consistent with that of the cache. In the write-back method, on a cache write hit, the system writes data into the cache and sets a "dirty bit" which indicates that the data has been written into the cache but not into the main memory. A cache controller checks for a dirty bit before overwriting any line of data in the cache, and if set, writes the line of data out to main memory before loading the cache with new data.
A computer system can have more than one level of cache memory for a given address space. For example, in a two-level cache system, the "level one" (L1) cache is logically adjacent to the host processor. The second level (L2) cache is logically behind the L1 cache, and main memory (e.g. DRAM) is located logically behind the second level cache. When the host processor performs an access to an address in the memory address space, the L1 cache responds if possible. If the L1 cache cannot respond (for example, because of an L1 cache miss), then the L2 cache responds if possible. If the L2 cache also cannot respond, then the access is made to main memory. The host processor does not need to know how many levels of caching are present in the system or indeed that any caching exists at all. Similarly, the L1 cache does not need to know whether a second level of caching exists prior to main memory. Thus, to the host processing unit, the combination of both caches and main memory is considered merely as a single main memory structure. Similarly, to the L1 cache, the combination of the L2 cache and main memory is considered simply as a single main memory structure. In fact, a third level of caching could be included between the L2 cache and the main memory, and the L2 cache would still consider the combination of L3 and main memory as a single main memory structure.
As the .times.86 family of microprocessors has advanced, additional functions have been included on the microprocessor chip itself. For example, while i386-compatible microprocessors did not include any cache memory on-chip, the i486-compatible microprocessors did. Specifically, these microprocessors included a level one, "write-through" cache memory.
Pentium-compatible microprocessors also include a level one cache on-chip. This cache is divided into a data cache and a separate code cache. Unlike the cache included on the i486-compatible microprocessor chips, the data cache on a Pentium chip follows a write-back policy. The cache is actually programmable on a line-by-line basis to follow a write-through or a write-back policy, but special precautions must be taken externally to the chip as long as even one line is to follow a write-back policy. The data cache on a Pentium chip implements a "modified/exclusive/shared/invalid" (MESI) write-back cache consistency protocol, whereas the code cache only supports the "shared" and "invalid" states of the MESI protocol. The MESI protocol is described in "Intel, "Pentium Processor User's Manual, Vol. 1: Pentium Processor Databook" (1993), incorporated herein by reference.
In Pentium-based systems, an L2 cache typically is part of a supporting chip set. One drawback of current L2 cache designs is that they include a performance penalty for setting the dirty bit. For example, one L2 cache that can be used is a write back cache which includes a tag store for storing L2 tags and a dirty bit store for storing L2 dirty bits. Typically, the tag store and dirty bit store are SRAMs. To save resources (cost, space, power, heat, silicon etc.), the tag store and dirty bit store can be combined onto one SRAM. For example, a 32k.times.9 SRAM can be used to store eight bit tags and a dirty bit for each line in the L2 cache, or a 32k.times.8 SRAM can be used to store a 7 bit tag and a dirty bit. However, such a configuration can slow down the system during some memory cycles. A 32k.times.9 SRAM will typically include one set of bidirectional pins for both reading and writing the tags and dirty bit. A default state is likely to be output. When writing dirty bits it will be necessary to use one half of a clock cycle to assert a write enable which would change the dirty bit pin to an input. A second clock cycle is needed to actually write to the dirty bit. Thus, using a bidirectional pin to write to and read from the dirty bit store can cause a performance penalty. In some designs, setting the dirty bit can cause a performance penalty even if the dirty bit store is separate from the tag store and/or has separate data input and output pins.
Since computers are judge by their price and performance, computer makers strive to increase the speed and efficiency of their computers without increasing costs. Thus, there is a need for a system of writing to a cache memory that reduces the performance penalty for setting a dirty bit.

System for using a dirty bit with a cache memory


A magnetic transistor circuit with the OR, NOR, NAND and AND functions has a first, a second, a third, a fourth magnetic transistor, and a routing line. These four magnetic transistors as ordinary transistors that can be turned on or turned off by the control of several metal devices respectively disposed around the magnetic transistors. The OR, NOR, NAND and AND logic functions of the binary system can be implemented by the control of these metal devices.

1. Field of Invention
The present invention relates to an circuit with the OR, NOR, NAND and AND functions. More particularly, the present invention relates to an circuit with the OR, NOR, NAND and AND functions configured by several magnetic transistors.
2. Description of Related Art
'OR', 'NOR', 'NAND', and 'AND' logic circuits are very important for IC circuit design. The designer can combine these four logic circuits each other or with other logic circuits to implement the required functions.
FIG. 1 is a CMOS circuit with the NAND logic function of the prior art. The CMOS circuit has two PMOS transistors 100 and 130 coupled in parallel, and two NMOS transistors 160 and 190 coupled in series. The NMOS transistor 190 couples to the low voltage end 140, and the PMOS transistors 100 and 130 couple to the high voltage end 120. The input signal 'X' at the input end 110 controls the PMOS transistor 100 and NMOS transistor 160. The Input signal 'Y' at the input end 150 controls the PMOS transistor 130 and NMOS transistor 190. The CMOS circuit generates the NAND logic function (output=(X·Y)′) at the output end 170.
The Giant Magnetoresistance Effect (GMR) is a quantum mechanical effect observed in structures with alternating thin magnetic and thin nonmagnetic sections. The GMR effect shows a significant change in electrical resistance from the zero-field high resistance state to the high-field low resistance state according to an applied external field.
Therefore, the GMR effect can be used to design the magnetic transistor. Thus, magnetic transistors can further be used to integrate a magnetic circuit without the expensive process and equipment. The magnetic circuit can be designed and manufactured with short programming time and high density.
Moreover, each ordinary logic circuit has only one function individually. Therefore, the ordinary circuits have to be designed or manufactured seperately to implement a function. The magnetic transistor circuit presented here can generate the OR, NOR, NAND and AND functions by the same circuit. Therefore, the design and manufacture cost can be reduced more than before.
For the foregoing reasons, there is a need to have a magnetic transistor circuit integrated by magnetic transistors.

Magnetic transistor with the OR/NOR/NAND/AND functions


An optical contact element for coupling a laser processing device to an object to be processed is described, wherein the laser processing device focuses a scanned laser beam through a surface of the object into a certain region of the object and the contact element comprises an entrance side for receiving the scanned laser radiation and an exit side imparting a defined surface curvature to the surface of the object upon contact therewith, wherein a diffractive optical element is provided on the entrance side, which element reduces the angle of incidence of the laser radiation on the surface of the object.

In material processing by means of laser radiation, the laser beam's exactness of positioning usually determines the precision achieved in processing. If the laser beam is focused into a processing volume, exact three-dimensional positioning is required. If the object to be machined has a deformable surface, it is usually indispensable in high-precision processing to know the surface shape or to keep any deviation of the surface shape from a predefined shape as small as possible. The above-mentioned contact element serves such purposes, because it imparts a desired surface curvature to the surface of the object to be processed.
In materials having only minor linear optical absorption within the spectral range of the processing laser radiation advantage is usually taken of non-linear interactions between the laser radiation and the material, most often in the form of an optical breakthrough being generated in the focus of the laser beam. Since the processing effect thus only takes place in the laser beam focus, exact three-dimensional orientation of the focal point is indispensable. Thus, the machining of larger areas also requires an exact depth position of the focal location in addition to two-dimensional deflection of the laser beam. Due to the contact element, known optical relationships, in particular relationships of diffraction, with the object are present. In addition, the contact element also fixes the object in a defined position relative to the processing device.
A typical application of such a contact element is the ophthalmic surgery method known as fs-LASIK, wherein a laser beam is focused in the cornea to a focal point with an order of magnitude of a few micrometers. In the focus, a plasma then forms which suddenly evaporates and disrupts the surrounding tissue. This type of interaction between laser light and tissue is referred to as photodisruption. Since photodisruption ideally remains limited to a microscopically small zone of interaction, precise surgical cuts can be performed within the eye. Local separation of corneal tissue is effected. A suitable sequential arrangement of the local separation zones thus generated realizes macroscopic cuts and isolates a defined partial volume of the cornea. Removal of said partial volume then achieves a desired change in refraction of the cornea, thus enabling correction of an eyesight defect.
Exact positioning of the laser beam is indispensable to carry out the method. A randomly involuntary movement of the human eye during treatment is problematic. Mechanical fixation of the eye or optical feedback with respect to the eye movement is required in order to minimize this factor of influence. This is why the above-mentioned contact element is used having a double function: Not only does it ensure the required optical properties when passing the laser beam into the cornea, but it also fixes the eye, preferably with regard to several degrees of freedom, particularly preferably with regard to all possible degrees of freedom. Movements of the eye relative to the laser processing device are thus prevented.
U.S. Pat. No. 6,342,053 proposes to fix the eye by means of a vacuum ring. A coupling medium in front of the eye significantly reduces the difference in refractive index with respect to the cornea. The use of this coupling medium facilitates optical correction of the system. Since said medium has a refractive index of >1, the beam deflection at the boundary surface is further reduced and any aberrations generated at this surface are reduced. In case the refractive indices of the contact glass and of the cornea are identical, no boundary surface exists from a geometrical/optical point of view.
A different concept is described in U.S. Pat. No. 5,549,632. The corneal curvature is nullified by means of a plane-parallel plate or is deformed by a concave or convex surface. This is effected by pressure on the eye. The eye is fixed, and the focused laser bundle is not affected negatively by excessively oblique incidence on a boundary surface. The pressure on the cornea inevitably leads to an increase in the internal pressure of the eye. From a medical point of view, this increase bears risks. Further, "flattening" the cornea in order to achieve a planar geometry is inconvenient for the patient.
High field strengths are a prerequisite for the process of photodisruption; these are realized by small focus diameters and short laser pulses. Small focus diameters can be achieved only with great apertures. Moreover, fields of treatment having a diameter of more than 8 mm are of interest. The geometry of the cornea results in a curved image field. No systems are known to reach an aperture of more than 0.3 with such fields. Therefore, the prior art either is either limited to smaller processing fields or works with planar geometry.
It is an object of the invention to improve a coupling element or a laser processing device of the above-mentioned type such that larger processing fields are also possible without planar geometries.


The disk brake includes a caliper having a plurality of claw portions. A carrier supports the caliper for sliding movement in a direction parallel to the axis of rotation of the disk. A pair of pads are disposed on opposite sides of the disk for sliding in the axial direction of the disk. A wear alarm member is attached to one of the pads, which is pressed by the claw portions of the caliper, at a position inbetween the claw portions. The wear alarm member has a mounting portion attached to the pad and a vibrating piece extending from the mounting portion in a direction intersecting the radial direction of the disk. The distal end portion of the vibrating piece is bent toward the disk at the periphery of the pad to form a contact portion.

1. Field of the Invention
The present invention relates to a disk brake which is attached to a vehicle, for example, an automobile.
2. Description of the Prior Art
In disk brakes, a wear alarm member has heretofore been employed to inform the driver of the wear of the brake pad. This alarm member has a portion that is secured to the support plate of the brake pad, and a contact portion that extends therefrom and bends at the edge of the brake pad support plate so as to extend toward the disk. When the brake pad has become worn, the contact portion comes in contact with the disk and produces sound, thereby giving an audible wear alarm signal to the driver.
The wear alarm member must be sufficiently long to generate vibration effectively. In order to obtain the required length, the conventional wear alarm member is shaped such that the intermediate portion of the member, which is contiguous with the portion secured to the brake pad support plate, is bent to extend away from the disk and then is turned back toward the disk. In order to prevent the portion that extends away from the disk from interfering with a part of the carrier of the disk brake or a claw portion of the caliper, the wear alarm member must be attached to the support plate at a position adjacent to the side edge of the brake pad, and the claw portion needs to be so shaped or positioned as to prevent interference with the wear alarm member. A cut portion may be formed in the claw portion for preventing this interference.
To produce a caliper having a claw portion with a cut portion, a forming die used to produce a caliper having claw portions without a cut portion cannot be used, and it is therefore necessary to modify the die or produce a new die, which invites an increase in the cost.


A control system for regulating a dispenser that includes a feeder bowl and a plurality of dispensing paths is disclosed. The control system includes a control unit for controlling a rotation drive for rotating the dispensing paths, a feeder bowl vibration device for vibrating the feeder bowl, and at least one dispensing path vibration device for vibrating the dispensing paths, such that the feeder bowl receives a plurality of items and supply the items uniformly to each of the dispensing paths, and the dispensing paths dispense the items singularly.

1. Field of the Invention
The present invention relates generally to control systems and methods of controlling the dispensing of items. In particular, the present invention relates to control systems and methods of controlling the dispensing of items from a vibratory dispenser.
2. Description of Related Art
Known control systems and methods of controlling the dispensing of items may be used to operate dispensers that receive and dispense a plurality of items. Known control systems and methods may operate dispensers, so that dispensers may dispense a plurality of items at different rates. Moreover, known control systems and methods may count dispensed items, so that items may be dispensed in predetermined quantities. Known control systems may measure a physical characteristic of dispensed items, e.g., known control systems may weigh dispensed items.
In known control systems, however, the accuracy of the count of dispensed items may be affected by operation of known dispensers. For example, the ability of known control systems to operate dispensers to dispense items singularly, e.g., in a single file, may improve the accuracy of the count of dispensed items. If two or more items are dispensed simultaneously, known control systems may count the items as a single item, thereby undermining the accuracy of the count of dispensed items. Thus, known dispensing control systems may reduce or limit the rate at which items are dispensed in order to improve the accuracy of a count of dispensed items.

Control systems and methods of dispensing items


Electrochemical systems for harvesting heat energy, and associated electrochemical cells and methods, are generally described. The electrochemical cells can be configured, in certain cases, such that at least a portion of the regeneration of the first electrochemically active material is driven by a change in temperature of the electrochemical cell. The electrochemical cells can be configured to include a first electrochemically active material and a second electrochemically active material, and, in some cases, the absolute value of the difference between the first thermogalvanic coefficient of the first electrochemically active material and the second thermogalvanic coefficient of the second electrochemically active material is at least about 0.5 millivolts/Kelvin.

Thermally regenerative electrochemical systems (TRES) are systems in which heat is converted into electricity in an electrochemical heat engine. The heat recovery strategy in TRES is based on the temperature dependence of the electrochemical potential of the system components. For the half reaction, A+n e−→B, the thermogalvanic coefficient α is defined as:
                    α        =                                            ∂              V                                      ∂              T                                =                                    Δ                                                                                S                                  A                  ,                  B                                                                    n                                                                                F                                                          (        1        )            where V is the electrode potential, T is temperature, n is the number of electrons transferred in the reaction, F is Faraday's constant, and ΔSA,B is the partial molar entropy change for the half cell reaction at isothermal conditions. For the full cell reaction, A+B→C+D (discharge), the thermogalvanic coefficient α is defined as:
                    α        =                                            ∂              E                                      ∂              T                                =                                                    -                                  1                                      n                                                                                F                                                                                ∂                    Δ                                                                                G                                                  ∂                  T                                                      =                                          Δ                                                                                S                                            n                                                                                F                                                                        (        2        )            where E is the full cell voltage and ΔG and ΔS are the change of partial molar Gibbs free energy and partial molar entropy, respectively, in the full cell reaction.
Generally, the voltage of the electrochemical cell depends on temperature; thus, a thermodynamic cycle can be constructed by discharging the electrochemical cell at T1 and charging the electrochemical cell at T2. If the charging voltage at T2 is lower than the discharging voltage at T1, net energy is produced by the voltage difference, similar to a thermomechanical engine whose theoretical efficiency is limited by Carnot efficiency.
Traditional TRES are often impractical, as such systems must often be operated at conditions that are incompatible with many processes in which heat recovery would be useful. Improved systems and associated methods would be desirable.

Electrochemical systems configured to harvest heat energy

The Board of Trustees of the Leland Staford Junior University


A building construction configuration comprising an assemblage of wood sheathing panels positioned adjacent one another to form a panel assembly having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips cover an area that is within the range of from about 5 to about 50 percent of the surface area of the panels. In another embodiment of the invention, there is provided a method of constructing a building comprising applying wood sheathing panels to a framework to form a building shell, bonding reinforcement strips of fiber reinforced polymer material to the wood sheathing panels to bond at least some of the wood sheathing panels to each other, and covering the building shell with a finished exterior.

This invention relates in general to strengthening wood-frame construction, and in particular, to a method of strengthening wood-frame construction and increase its resistance to high wind, earthquake or blast loadings by applying strips of fiber reinforced polymers to the panels. A very common wood frame construction method uses wood or steel studs or wood or steel framing with plywood or Oriented Strand Board (OSB) sheathing panels or stucco sheathing. The framing/sheathing combination forms shear walls and horizontal diaphragms which resist horizontal and vertical loads applied to the structure. This form of construction is used in the majority of single family homes in the United States, as well as a significant portion of multi-family, commercial and industrial facilities.
While the system has generally performed well, the economic losses in the United States due to natural disasters, such as hurricanes, earthquakes and tornadoes, have been mounting. The economic losses caused by these natural disasters in the United States has averaged about $1 billion/week in recent years. Most of these losses are due to hurricanes (80%) and earthquakes (10%). For example, loss of roof sheathing under hurricane winds has often been attributed to improper fastening of the sheathing to the framing, such as by the use of larger nail spacing than allowed by code, nails missing the support framing members, or over-driven nails. Loss of sheathing in hurricanes weakens the roof structure and can lead to roof failures. The water damage resulting from a loss of roof sheathing or roof failures has been a major contributor to economic losses in hurricanes. Surveys also show that a significant portion of the damage resulting from hurricanes or earthquakes occurs in nonstructural parts of the home due to excessive deformation or movements of the structure. The cost to repair nonstructural damage often makes it necessary to rebuild the structure rather than to repair it.
While the knowledge to mitigate hurricane and earthquake damage exists today, building code provisions are often misunderstood by builders, and compliance with regulations is difficult to enforce because of the difficulty of inspecting in the field. As a result, surveys show that a significant portion of the damage to homes and property caused by natural disasters is due to lack of conformance to codes. Improper connections between walls at building comers, such as non-overlapping top plates or improper or missing hold-downs to tie the shear walls to the foundations, are further examples of poor construction practices that are difficult to inspect.
Therefore, there is a need for a simple, easy-to-inspect, inexpensive construction method to strengthen and stiffen conventional construction for improved performance against hurricane and earthquake damage. The construction method should increase the strength and ductility of wood buildings and reduce the deformation of the buildings to limit damage to non-structural members.
The above objects as well as other objects not specifically enumerated are achieved by a building construction configuration comprising an assemblage of wood sheathing panels positioned adjacent one another to form a panel assembly having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips cover an area that is within the range of from about 5 to about 50 percent of the surface area of the panels.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips cover at least 20 percent of the joints, thereby bonding together substantially all of the panels in the building roof.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof having elongated joints between adjacent panels, and reinforcement strips of fiber reinforced polymer material bonded to the panels. The reinforcement strips are concentrated at the ridge, eave and edge areas of the roof.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of wood sheathing roof panels positioned adjacent one another to form a building roof, and an assemblage of wood sheathing shear wall panels positioned adjacent one another to form a building wall. A joint is formed between the roof panels and the shear wall panels, and reinforcement strips of fiber reinforced polymer material are bonded to at least some of the roof panels and at least some of the shear wall panels.
In another embodiment of the invention, there is provided a building construction configuration comprising an assemblage of shear wood sheathing wall panels positioned adjacent one another to form a first building wall, and an assemblage of shear wood sheathing wall panels positioned adjacent one another to form a second building wall, where a joint is formed between the first building wall and the second building wall. Reinforcement strips of fiber reinforced polymer material bonded to at least some of the shear wall panels in the first building wall and at least some of the shear wall panels in the second building wall.
In another embodiment of the invention, there is provided a method of constructing a building comprising applying wood sheathing panels to a framework to form a building shell, bonding reinforcement strips of fiber reinforced polymer material to the wood sheathing panels to bond at least some of the wood sheathing panels to each other, and covering the building shell with a finished exterior.

Building construction configuration and method

University of Maine System Board of Trustees


A cylinder apparatus capable of effectively restraining a loss of energy with a simple structure at a low cost. When a piston 16 of a main cylinder 11 cuts off a communication between a subchamber 20 and a supply/exhaust passage 32, a pressure of the subchamber 20 is pushed by the piston 16 and thereby increased. However, an exhaust fluid from the subchamber 20 having the increased pressure is fed to a subcylinder 62. A piston 48 is moved while controlling a velocity by a flow rate control valve 70 in synchronization with the piston 16. This arrangement eliminates a necessity for a special position detector, etc.. The structure is therefore simplified, and the cost decreases. Simultaneously, the energy can be effectively utilized because of employing the exhaust fluid.

1. Field of the Invention
The present invention relates to a cylinder apparatus in which a subcylinder is operated by a fluid exhausted from a main cylinder.
2. Related Background Art
Generally, in the industrial field, when a piston of a certain cylinder moves to a predetermined position, a piston of another cylinder starts moving in synchronization with the former cylinder. In this case, according to the prior arts, a position detector detects a position of the piston of the cylinder. At the same time, when the piston of the cylinder moves to the predetermined position, a changeover valve is changed over in accordance with a signal transmitted from the position detector. The piston of another cylinder is moved by supplying the fluid from another pump to another cylinder.
This type of conventional cylinder apparatus, however, involves the use of a special position detector, a changeover valve and intricate piping and wiring. This presents such problems that the structure becomes complicated, and the cost increases. Besides, there arises a problem, wherein the fluid supplied to another cylinder is normally returned to a tank (when not supplied to another cylinder), and a large loss of energy is to be caused.


Swivel actuator device for lift control of a gas exchange valve in a cylinder head of an internal combustion engine comprising a swivel motor having a shaft on which is provided a first operating element having a control path for opening the gas exchange valve, whereby a second operating element having a second control path provided on the first operating element. Due to the arrangement of the swivel actuator device, less electric power is needed at low rotational speeds and processing of the fuel mixture is improved.

The invention relates to a swivel actuator device for lift control of a gas exchange valve in a cylinder head of an internal combustion engine.
Currently unpublished German Patent Application 101 40 461 describes a rotary actuator device for lift control of a gas exchange valve in a cylinder head of an internal combustion engine. The lift is controlled via an electric motor driven by engine characteristics maps; the rotor of this motor has a shaft with a control cam in a rotationally fixed connection. During operation of the internal combustion engine, the motor swivels and/or swings back and forth and the control cam periodically presses the gas exchange valve into its open position via a swivel lever. The gas exchange valve is closed by the spring force of a valve spring. An additional spring is mounted on the shaft in order for the electric motor not to have to overcome the total spring force of the valve spring in opening the gas exchange valve. The forces of the valve spring and the additional spring are such that in periodic operation of the rotary actuator device, the kinetic energy is stored either in the valve spring or in the additional spring, depending on the position of the gas exchange valve. As a result of this measure, the power consumption in operation of the rotary actuator device is reduced. The control cam is alternately controlled by the electric motor and has a single cam flank designed with a ramp serving for opening and closing between a cam cup and a base circuit; in a diametric area, the control cam has a base circle section that is lengthened in the circumferential direction for this cam flank, a stop face for a first rotational stop on the motor side or on the cylinder head side following this base circle section and being directed essentially radially to the cam cup region.
One disadvantage of the rotary actuator device described here is the high power consumption at low rotational speeds.
The object of the present invention is to reduce power consumption at low rotational speeds for a generic rotary actuator device.
This object is achieved by providing a second operating element having a first control path, situated on the first operating element. This invention expands the existing swivel actuator device through a second contrarotating operating element with a smaller lift in comparison with the main cam. This second operating element does not open the valve completely and is used only for small lifts in the range of low engine rotational speeds. At low rotational speeds of the internal combustion engine, the swivel actuator device receives electric current so that the shaft swivels only in the direction of the second operating element, whereas at high rotational speeds it is swiveled only in the direction of the first operating element. Due to the smaller lift, the swivel actuator device advantageously consumes less current at low rotational speeds.
In further embodiments, the two operating elements form a double cam which can be operated smoothly in two directions. In addition, it is simple and inexpensive to manufacture a double control path designed in this way, such that its zero lift ranges are next to one another.
With embodiments providing less than full lift, the power consumption is low at low rotational speeds. Furthermore, valve noise generated by the gas exchange valve striking the valve seat is reduced by the inventive design. The second operating element equalizes the torques of the spring element, an actuator spring, against the torques of the valve spring. The resulting torque on the camshaft is almost zero, depending on tolerances, and thus the camshaft can be kept almost currentless in any angular position of the second operating element. Such a system has low dynamics because it is built up merely by the torque buildup by the slewing motor (through electric power supply). Another advantage that can be mentioned is the improvement in the gas dynamics in load exchange because supersonic speeds can be generated in the valve gap due to the small valve lift, which thus makes a significant positive contribution toward good processing of the fuel mixture. In one embodiment in particular, system overshooting does not have any effect because the valve lift cannot be altered in these ranges.
To improve the low dynamics of the second operating element, the second control path may be divided into acceleration and deceleration. To do so, the control path is divided into two ranges. In the first lift range, above zero lift or a defined value (from 0.6 mm to 1.5 mm lift), the kinematic torque of the spring element is compensated only to a slight extent so that a spring-induced acceleration is impressed upon the swivel actuator device. In the second lift range (e.g., from 1.5 mm to approx. 3.5 mm), the kinematic torque of the spring element is overcompensated, so that a spring-induced deceleration is imposed upon the swivel actuator device over this lift range. Due to this design, it is possible in a simple way to have a positive influence on the dynamics of the swivel actuator device, especially at low valve lifts.
It is possible to arrange the two operating elements either radially on the outside circumference of the shaft, so that multiple gas exchange valves can be operated by one swivel actuator device, and/or apply a rocker arm path to the end face of the shaft so that a single gas exchange valve can be controlled with it.
The internal friction of the system is reduced with the arrangement of a power transmission element between the operating element and the gas exchange valve.
The inventive swivel actuator device according to patent Claim 12 may be arranged advantageously on the intake and/or exhaust ends of the cylinder head of the internal combustion engine. This principle of equal parts permits inexpensive production.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Pivoting actuator system for controlling the stroke of a gas exchange valve in the cylinder head of an internal combustion engine


A panel component (1) comprises a plastic substrate (3), a display (2), and a metal panel (6) covering an outer surface of the plastic substrate (3). The metal panel (6) is fixed on the plastic substrate (3). The display (2) is mounted on the plastic substrate (3) through a display mounting structure. A light-transmitting structure is arranged in the metal panel (6) in a region corresponding to the location of the display (2). The metal panel (6) enables the panel component (1) to have good decorating effect, and the light-transmitting structure ensures clear display. Further disclosed are an air conditioner provided with the panel component (1) and a method for manufacturing the air conditioner.

Commonly, an air conditioner, with the aid of an air cooling component, a heating component, or an air purifying component, is an appliance for cooling or heating the room, or purifying the air in the room so as to make the indoor environment more comfortable. This type of air conditioner is provided with a ventilation device, an air cooling and heating device, and an air purifying device. The ventilation device forces the air to circulate indoors, takes in indoor air to exchange heat, or purifies the air and then exhausts the air to the indoors. People have been improving the air conditioners. Especially, as the indoor unit of an air conditioner is installed indoors, the user's expectations for the decorative effect of the indoor unit of an air conditioner in the indoor environment are becoming higher and higher.
The panel component of the air conditioner in the prior art is made of plastic, which lacks metallic texture. As for high-grade air conditioners, part or whole of the panel component is made of metal in order to highlight the texture, which creates impressions of high quality. However, it is inconvenient for mounting a display because of limitations on processing an all-metal panel, moreover, metal material is opaque and cannot perform clear display.

Panel component, air conditioner and method for manufacturing air conditioner

Gree Electric Appliances, Inc. of Zhuhai


A composite silicon carbide article and its method of making in which a surface layer or film of silicon carbide is deposited, for example by chemical vapor deposition (CVD), over a free standing silicon carbide substrate, as is formed by bulk methods such as sintering and hot pressing. The article is advantageously used in a plasma reactor, especially an oxide etcher for semiconductor fabrication, and may be any of several parts including the chamber wall, chamber roof, or collar around the wafer. The bulk SiC provides an inexpensive and strong support structure of perhaps a complex shape while the CVD SiC film has advantages for plasma processing and may be tailored to particular uses. The composite SiC structure is particularly useful in that the electrical conductivities of the bulk SiC and film SiC may be separately controlled so as to provide, among many possibilities, a grounding plane, a window for RF electromagnetic radiation, or both. The ultra-high purity achieved in CVD silicon carbide also benefits the control of micro-contamination inside the reactor chamber, a key factor for increased device yield.

Plasma reactors, for example as used in fabricating semiconductor integrated circuits, can present extreme demands upon the materials constituting the chamber walls and other components within the reactor that are exposed to the plasma. A particularly difficult environment is presented by an oxide etcher used in etching through layers of silicon dioxide in semiconductor integrated circuits.
Such a reactor is shown in schematic cross section in FIG. 1 and closely follows the Centura HDP Oxide Etcher, available from Applied Materials, Inc. of Santa Clara, Calif. This reactor is exemplary only and is described here to provide an understanding of the operation of a plasma reactor. The reactor 10 includes a vacuum chamber 12 into which is loaded a silicon wafer 14 that is supported on a pedestal 15. In the illustrated reactor, the wafer 14 is held by a plasma focus ring 16 and a clamping ring 18, and an annular plasma guard 20 surrounds the pedestal 15 to protect it from the plasma. If an electrostatic chuck is used in the pedestal 15, it may be surrounded by an unillustrated free standing collar which controls the plasma conditions in the neighborhood of the wafer 14. This description is intended to be illustrative only and not defining the preferred configuration.
The vacuum chamber 12 includes a cylindrical dielectric wall 22, outside of which is wrapped an inductive coil 24 for coupling RF energy into the chamber 12 so as to create therein a high-density plasma of processing gases admitted into the chamber 12 by unillustrated gas ports. A roof 26 defines the upper boundary of the chamber 12. The roof 26 is often grounded or even biased by an RF electrical source and thus preferably functions as a counter electrode. Alternatively or additionally, the roof 26 is preferably temperature controlled by a heater/cooler 30, which also serves as the vacuum-sealing roof, and may be electrically connected thereto so as to be commonly biased or grounded. The foregoing reactor structure is being given only by way of example so as to explain the usefulness of the invention, and the invention is equally applicable to other reactor structures and is not limited to oxide etchers.
In oxide etching, a fluorocarbon plasma, for instance of CF.sub.4 or C.sub.3 F.sub.8 among other examples, is used to etch through an oxide layer, typically silicon oxide overlying silicon or polysilicon. To assure uniform etching, it is important that the etching process strongly preferentially etch the oxide over the silicon. In the normal parlance, the etch should be selective to silicon.
The plasma is largely supported by the inductive coil 24, which couples a large amount of RF energy into the chamber 12 and thus generates a high-density plasma (HDP), which allows a very high etching rate of the oxide layer on the wafer 14.
However, obtaining selectivity, uniformity of selectivity over the wafer, and reproducibility of selectivity over slightly varying conditions has provided technological challenges in commercializing HDP oxide etchers. It was early recognized, as Collins et al. have described in European Patent Publication 552,491-A1, that a chamber element such as the roof 26 be formed of silicon. Under the proper conditions, the solid silicon provides species of silicon which combine with fluorine radicals in the plasma so that a fluorine-deficient carbonaceous polymer forms on the exposed elemental silicon surfaces, thereby enhancing the oxide-over-silicon selectivity. It was however also recognized that the temperature of the chamber silicon including the silicon roof 26 was important in controlling the process and that proper temperature control means for heating as well as cooling the chamber silicon should be incorporated into an oxide etcher, for example, the heater/cooler 30. It was also recognized that control of electrical biasing of the roof 26 could likewise be used to control the process.
Thereafter, attention passed to the wall 22 inside the inductive coil 24, which has been typically formed of quartz, a crystalline form of silicon oxide. Rice et al. disclose in U.S. Pat. No. 5,477,975 regulating the wall's temperature relative to that of the roof 26 to control the selectivity. It has been further recognized that other parts surrounding the wafer 14 need to have their temperature controlled to control the process. Such parts, which hitherto have been typically made of quartz, include the clamping ring 16, the plasma guard 18, and the plasma ring 20.
However, the temperature control of quartz parts is difficult. Quartz is both an electrical and thermal insulator. Its coefficient of thermal conductivity is less than 1 W/m.multidot.K, a relatively low value, so that it is difficult to closely control the temperature of the entire surface of a quartz piece exposed to the plasma. Furthermore, quartz has a chemical composition closely resembling that of the silicon oxide layer being etched in the semiconductor oxide etch reactor. Thus, one must assure that the quartz part is being operated in a deposition or slow etch mode rather than a strong etch mode while the wafer of similar composition is being strongly etched. If not, the quartz parts will have short lifetimes and hence impose a high cost of replacing consumable parts, both in terms of parts cost and machine down time. Furthermore, the quartz, although it is a silicate material providing some silicon scavenging, also produces a relatively uncontrollable amount of CO and CO.sub.2 from the reaction between, for example, CF.sub.4 and SiO.sub.2. The resultant carbon monoxide and dioxide are particular problems for selectivity to photoresist. Also, quartz is a ceramically formed material and typically includes large amounts of non-silicate components, which become contaminants in the fluorocarbon etching environment. Even further, the etching of the quartz can undercut surface portions to the extent that particles of quartz are separated from the reactor elements and fall onto the wafer as fatal particles. Oxide etching is particularly critical against particles since the etching produces interfaces between two electrically conducting parts, one of which may be semiconducting and any particle falling on the interface before deposition of the subsequent layer can seriously affect the electrical characteristics of the junction across the interface.
Collins et al. have suggested in European Patent Application 601,468-A1 and in U.S. patent application, Ser. No. 08/597,577, filed Feb. 2, 1996 that an inductive coil be placed in back of the silicon roof 26. Further, in the latter, Collins et al. have suggested that other parts of the chamber, including the side walls 22 in front of the RF coils 24 be formed of silicon, either in its crystalline or polysilicon structure. The silicon composition provides some scavenging functions and also avoids contamination by quartz or other ceramics. However, silicon is a semiconductor, not a dielectric. As described by Collins et al., the silicon of the proper doping and thickness can advantageously also be electrically biased, either DC or RF, even while, in a preferred usage, electromagnetic radiation is being propagated therethrough. However, silicon in such uses presents many compromises and disadvantages. First, silicon in such large dimensions is not readily available at reasonable prices, particularly in times of shortage of polysilicon. Secondly, silicon, although affording relatively high structural strength, is prone to fracture from local micro-defects arising from its growth in the form of polysilicon and its subsequent machining. Thirdly, semiconducting silicon (bandgap of about 1.2 eV) affords an uneasy compromise between structural strength and electromagnetic transparency. Electromagnetic radiation can only penetrate a semiconductor or other conductor to the extent of a skin depth which can be expressed as ##EQU1## where f is the frequency of the electromagnetic radiation in hertz, .mu..sub.0 is the magnetic permeability in H/m, and .rho. is the bulk DC plasma resistivity of the semiconductor in ohm-m. The penetration of electromagnetic radiation through a conductive sheet is generally an exponential function of the sheet thickness z having the general form to first order of where surface effects are disregarded. These relationships show that the transparency of a layer depends on both the material resistivity and the frequency of the electromagnetic radiation. The functional dependence (2) shows that for a thickness of no more than the skin depth, the resistive absorption is less than 64%; for a thickness of no more than one-third the skin depth, the absorption is less than 29%; and for a thickness of no more than one-tenth the skin depth, the absorption is less than 10%.
The skin depth for available semiconductor materials at reasonable operating temperatures may be considerably less than a realistic structural thickness, even for vacuum wall members. A typical inductively coupled plasma reactor uses an RF source with a frequency of 2 MHz. For this frequency and for a non-magnetic material, the estimated skin depths for representative material resistivities are given in TABLE 1
TABLE 1 ______________________________________ Resistivity Skin Depth (ohm-cm) (mm) ______________________________________ 0.1 1.13 0.3 1.95 1 3.56 3 6.17 10 11.3 30 19.5 100 35.6 ______________________________________
Many have recognized that plasma reactor chamber parts can be formed of silicon carbide, both for its high-temperature performance and for its fluorine-scavenging characteristics. However, we observe that bulk silicon carbide, at least in its sintered or hot-pressed forms, is inadequate at least in a fluorine etching environment if few particles and long part life are to be attained and if high chemical purity is required in the wafer processing chamber. Silicon carbide is sintered by mixing a silicon carbide powder with a generally pliable sintering aid. The sintering aid has a complex and ill-defined composition producing effective impurity levels on the order of hundreds of parts per million, which greatly exceed the parts-per-billion scale required for wafer processing chambers. Also, the sintering aid, even after it has been hardened in the sintering process, produces a highly granular structure that exhibits a strongly differential pattern of etching, thus becoming a mechanism for producing particulates. In contrast, in CVD SiC, the impurity levels can be controlled, if required, down to less than 100 ppb (parts per billion). Further, our experiments show that CVD SiC demonstrate uniform etch profile when being etched by a fluorocarbon etchant.
Silicon carbide is well known as a susceptor material for RF induction heating of a chamber or wafer support within the chamber. Its thermal conductivity is in the range of 100 to 200 W/m.multidot.K, vastly superior to quartz. An RF coil wrapped around the chamber induces eddy currents in a highly conductive silicon carbide part to thereby heat it to high temperatures, such as are required for thermal CVD, as disclosed by Ban in U.S. Pat. No. 4,401,689. Induction heating is to be contrasted with inductive coupling of RF power into a plasma reactor chamber. Plasma reaction chambers are usually operated at much lower temperatures, and the RF energy should be coupled into the plasma and not into chamber parts. Hence, any silicon carbide parts used in a reaction chamber, at least in the vicinity of the coils, should have relatively high electrical resistivity, for example, above 10.sup.4 ohm-cm.
Silicon carbide composites are well known in which a bulk piece of silicon carbide is coated with a thin film of silicon carbide using a chemical vapor deposition (CVD) or similar process. Such composites include resistive heaters, as disclosed by Ito et al. in U.S. Pat. No. 4,810,526, and rugged mirrors, as disclosed by Hotate et al. in U.S. Pat. No. 5,448,418. Matsumoto et al. in U.S. Pat. No. 4,999,288 discloses using a silicon carbide composite as a diffusion tube for heat treating semiconductor wafers at about 1200.degree. C. According to Matsumoto et al., a 500 .mu.m-thick silicon carbide film is CVD deposited on the interior of a reaction sintered silicon carbide tube, and the film has a low concentration of iron impurities, although this level is defined as 5 parts per million (ppm). If desired, an interfacial region in the silicon carbide tube can be depleted of silicon. Electrical resistivity is immaterial in most diffusion tubes.

Silicon carbide composite article particularly useful for plasma reactors


Power converters having reduced body diode conduction loss, reduced reverse recovery loss and lower switching noise, among other benefits, have a resonant capacitor Cr connected across an unfiltered output. The resonant capacitor Cr resonates with the leakage inductance Lk of the transformer. The resonant capacitor and leakage inductance are selected such that ½ a LC resonance period is equal to an ON time of each secondary switch S1 S2. The resonance provides zero current switching for secondary switches S1 S2, eliminates zero body diode conduction during dead times, and eliminates reverse recovery losses in the secondary switches. The present invention is applicable to many different circuit topologies such as full bridge, active clamp forward, push-pull forward, and center-tap secondary. The present converters provide high energy conversion efficiency and high frequency operation.

Synchronous power converters are widely used in computer and telecommunication electronics. Such power converters typically convert 48 volt bus power to lower voltages (e.g. 12V, 5V and 1.2V) needed for operating microprocessors and the like.
Modern electronics are decreasing in size and typically require increased operating current at lower voltages. As a result, power converters must provide more power while occupying less circuit board space. In order to meet these requirements, power converters must operate at higher frequencies. A high operating frequency allows for smaller passive components. However, high operating frequencies greatly increase body diode conduction losses, reverse recovery losses and switching losses. These losses must be reduced in order to increase the operating frequency of next-generation power converters.
Another problem with high frequency operation is switching noise. The reverse-recovery charge of the switches creates high voltage spikes. When high voltage spikes are present, switches tolerant of high voltages must be used. High voltage-rating switches typically have high ON-state resistance (Rds(on)) and therefore higher conduction loss. Hence, a reduction of the voltage spikes would allow the use of low voltage, low loss switches and would provide an increase in operating efficiency.
FIG. 1 shows a conventional power converter with a full bridge primary circuit 10 and a center-tapped secondary circuit 12. The secondary circuit has an output capacitor Co and an output inductor Lo. The output capacitor is as large as possible, with typical values of about 300 microfarads. A load (not shown) is connected across the output capacitor Co. FIG. 2 shows a timing diagram illustrating the typical operation of the circuit of FIG. 1. Horizontal lines indicate the ON times of switches Q1 Q2 Q3 Q4 S1 and S2. As illustrated, these switches are operated in two groups, Q2, Q3 and S2 and Q1, Q4 and S1, and the groups are operated in an alternating, generally complementary fashion. However, some so-called dead time 14 is provided between the on time of the respective groups to prevent shorting of Vin or the secondary winding of the transformer. During dead times 14, the body diodes of secondary switches S1 S2 conduct current pulses 16 due to the inductance of the transformer and/or any output inductance which may be included in the power converter circuit, resulting in substantial energy loss and reverse recovery loss. Also, high voltage spikes 18 and ringing occur across the switches S1 S2. The body diode conduction loss and reverse recovery loss increase as operating frequency increases, and result in lower power conversion efficiency at higher switching frequencies.
It would be an advance in the art of power conversion to provide a power converter with reduced body diode conduction loss, reduced reverse recovery loss and reduced switching noise. Such circuits could operate at high frequency and have very small size because the higher frequency switching allows passive components of reduced size to be employed.

Power converters having output capacitor resonant with autotransformer leakage inductance

Virginia Tech Intellectual Properties, Inc.


A music search method for finding a desired song in a song database. The method comprises generating a difference sequence for each song in the song database by determining the relative difference between adjacent notes. Next, a note sequence is chosen for the song to be found within the song database. A difference argument is generated for the note sequence by determining the relative difference between adjacent notes. The difference argument for the note sequence and the difference sequence for each song in the song database is compared. The desired song is found if the difference argument for the note sequence corresponds to a portion of the difference sequence for the desired song, or if the net difference at the closest match position is within a set difference threshold.

The present invention generally relates to a method of searching for a song and more particularly to a simplified search method adapted for use on a computer.
As is well known, songs are composed of music and words. The music comprises the ordering of tones and sounds (i.e., notes) in succession to form temporal relationships that produce a composition having unity and continuity. Often times, a musician or music lover will know the tune (i.e., melody) of a song, yet not know the title, words, or music associated therewith. The musician or music lover would like to know the name of the song in order to find the sheet music for it and/or recordings of the desired song. In the prior art, if a music lover and/or musician knows the tune of the song, he/she has a difficult time in finding the title of the song.
In order to facilitate searching for songs, prior art computer systems have been designed which search for matches between notes entered by the searcher and the notes of the song. Typically, in the prior art, a song database is created by entering the notes comprising the music into a computer memory. The song is stored electronically wherein each note is exactly duplicated in the memory of the computer. In order to perform a search with the prior art system, the searcher enters a sequence of notes of the song into the computer, and the system will attempt to find a match between the entered notes and the notes in the database.
Prior art music search systems have been inadequate in that the music is encoded into the database in a fixed key. The database of the prior art music search engine comprises a note listing for each song. The note listing will be generated in the key of the song as written on the music or performed by the encoder. The prior art music search system searches for music corresponding identically to the notes entered by the user. Therefore, in order to find a song, the user must enter notes in the same key and the identical sequence as they were encoded into the song database. The search system will find songs that identically match the notes entered by the user. If the user enters notes in a different key, or makes a mistake in the value of a note, the search system will not find a match for the song. In order to find songs entered in a different key by the user, the prior art search system must either include a database of songs transposed into different keys or transpose the notes entered by the user into the key that the database songs are entered. Neither method is ideal because of the inefficiency of the music search. Specifically, if all songs are entered into the database in all possible keys, the system must search through many unnecessary song versions to find a match. Similarly, if the system converts the entered notes into all possible keys, the system must allocate resources to transpose the notes, and then perform multiple searches (i.e., one for each different key) In either case, the prior art search system will only produce the desired result if the user correctly enters a sequence of notes.
As described above, prior art music search systems require a large amount of computational resources, and as such are highly inefficient. They are also impractical due to the fact that various interpretations of different stylistic impressions of a song (during encoding) and imperfect recollection of a song's exact note sequences (during searching) are common and inhibiting factors. The present invention addresses the problems associated with the prior art music search systems by providing a key-independent music search engine operative to determine a match between the notes entered and the notes of a song using computational resources more efficiently. Additionally, the present invention provides a music search engine capable of finding the closest matches for songs, even if the entered note sequence contains errors. Furthermore, the present invention provides a music search engine that facilitates the analysis and categorization of music in a fast and efficient manner. The music search engine of the present invention additionally provides a system whereby songs found by the system may be transposed into a key selected by the user.


An active pixel includes a a photosensitive element formed in a semiconductor substrate. A transfer transistor is formed between the photosensitive element and a floating diffusion and selectively operative to transfer a signal from the photosensitive element to the floating diffusion. The floating diffusion is formed from an n-type implant with a dosage in the range of 5e13 to 5e14 ions/cm2. Finally, an amplification transistor is controlled by the floating diffusion.

Image sensors have become ubiquitous. They are widely used in digital still cameras, cellular phones, security cameras, medical, automobile, and other applications. The technology used to manufacture image sensors, and in particular CMOS image sensors, has continued to advance at great pace. For example, the demands of higher resolution and lower power consumption have encouraged the further miniaturization and integration of the image sensor.
A typical image sensor includes a pixel array of rows and columns comprised of individual pixels. Each pixel includes a photosensitive region and a readout region. For one commonly used type of pixel (the four transistor pixel), a transfer transistor transfers the signal output by the photosensitive region to a floating diffusion. The signal is then held by the floating diffusion until it can be read out by the readout portion of the pixel.
The floating diffusion region of a pixel is an important structure. Currently, the floating diffusion region is formed as an N+ implant in a semiconductor substrate. This enables the use of standard transistors which are adjacent to this floating diffusion (such as the transfer transistor and reset transistor). The use of the N+ implant to form the floating diffusion also provides a good ohmic contact between a contact plug and the floating diffusion.
However, there have been found to be several performance issues with this type of floating diffusion. First, the N+ implant creates an amorphous region that rearranges to reform the silicon crystalline lattice during subsequent thermal steps by a process known as solid phase epitaxial (SPE) regrowth. This regrowth begins simultaneously at several different physical locations on the floating diffusion. Where the regrowth fronts meet, a stacking fault can occur. The presence of a stacking fault in the floating diffusion will result in a much higher floating diffusion junction leakage with a consequent reduction in imager performance and lower yield.
Secondly, the high N+ implant dosage gives rise to high electric fields in the floating diffusion region, which results in increased floating diffusion junction leakage. Thirdly, the N+ implant with its high concentration diffuses laterally under the adjacent gates (the transfer gate and reset gate) and degrades their off state current performance and their short L punch-through performance. This limits the device scaling of these transistors.

Image sensor and pixel having an optimized floating diffusion


A method and system is disclosed for determining a probability that an encountered platform was of a specific type given that a plurality of emitters exist on the platform and each emitter has a computed probability that it is of each of a set of types. A preprocessing stage operates on a description of the environment and determines the probability of a set of events that are independent of any observation. A runtime processing stage uses the terms computed in the preprocessing stage along with data assembled from a set of observations to determine the conditional probability that a particular platform type was the type encountered.

This disclosure is directed to determining the likelihood that particular type of emitting platform was detected by a receiver, and more particularly, to determining that a specific target platform type of a plurality of possible platform types was detected by a receiver on a tracking platform, the plurality of possible platform types having at least one emitter of a plurality of emitter types.
Any random event that can be observed has a set of possible outcomes. Each of the outcomes has some probability of occurring. The probability that each outcome might occur can be computed using two sources of information. The first piece is deterministic knowledge of the environment which isn't based on any unique information. This data encompasses statistics about the event itself, statistics about events which influence the event of interest, and events that can only have a single, known outcome. The second piece of information is an observation from the events surrounding the event of interest. Events whose outcome is influenced by the event of interest or influence the outcome of the event of interest are called dependent events. Knowledge of how dependent events correlate with the event of interest and observations of the outcomes of dependent events can be used as clues to help compute a more accurate estimate of the outcome of the event of interest.
If it were possible to tabulate every possible outcome of some event and somehow determine the frequency of each possible outcome using an infinite set of observations it would be possible to perfectly know the unconditional probability of each of the outcomes. Unconditional probability is the probability that an event occurs without any information about the circumstances surrounding the event. The problem with this concept is that an infinite number of observations cannot be taken before we start coding a solution to the problem. Without an infinite number of trials it is impossible to be sure that the tabulated list of outcomes is truly complete. This means that certain assumptions must be made based on a statistical certainty that the model is complete and accurate.
The observation portion of the estimation process is plagued with a similar problem. If it were possible to have a perfect understanding of the way all observable events interact with the event of interest then it would be possible to perfectly know the conditional probability of the event. This requires perfect knowledge of the unconditional probability as well. Again, it is impossible to know all the events that have some influence over the event of interest, or even exactly how a single event influences the event of interest. Assumptions must be made about which events are relevant and the accuracy of the model of the dependency of events.

Method and system for identifying target platform

BAE Systems Information and Electronic Systems Integration Inc.


A tether anchor assembly is coupled to a vehicle allowing a child seat tether to be connected thereto. The anchor assembly includes a mounting bracket, a receiver bracket, a nylon loop and a boot. The mounting bracket is configured to be fixedly secured to the vehicle. The nylon loop extends through both the mounting bracket and receiver bracket. The boot includes a channel for concealing the receiver bracket and the loop when not in use.

1. Field of the Invention
The invention relates to tether anchors for securing child seats to automotive vehicles. More particularly, the invention relates to a tether anchor that is concealable in a boot when it is not in use.
2. Description of the Related Art
Automotive vehicles include top tethers for connecting child seats to tether brackets secured to the vehicle. It is known in the prior art to utilize a rubber band for holding a loop and anchor in a stowed position when not in use. Rubber bands are not, however, user friendly. Further, rubber bands have a 'cheap' appearance and are not robust for day-to-day use.
It remains desirable to provide an improved tether arrangement that provides a better appearance for the loop and anchor when not in use, and is more user friendly compared to conventional designs.

Child seat top tether rerouter and bracket

Toyota Motor Engineering & Manufacturing North America, Inc.