A circuit board includes an insulating substrate having opposed first and second surfaces and a thickness; and first and second conductive layers disposed on the first and second surfaces of the insulating substrate, respectively, wherein the first conductive layer has an end surface projecting outwardly from the first conductive layer in a direction generally parallel to the first surface of the insulating substrate, and a contact surface in contact with the insulating substrate and joining the end surface at a junction, wherein the end surface is spaced from the first surface of the insulating substrate except at the junction.

1. Field of the Invention
The present invention relates to a circuit board for mounting a component such as a semiconductor electronic device and, more particularly, to a circuit board for use, at high voltage.
2. Description of the Related Art
Circuit boards constructed with a metal plate such as copper bonded to a base substrate of alumina or aluminum nitride are now widely used in a power transistor module or a switching power supply module. Various structures of circuit boards of this type, and various production techniques thereof, are known in the art. Some of these are disclosed for example in: (1) Print Circuit Board Handbook, Second Edition, Completely Revised, Japan Print Circuit Industry Association, 1987; (2) Japanese Patent Publication No. 60-4154 (1985); and (3) Journal of the Institute of Metals, Vol. 22, No. 1, pp. 3-7, 1983. FIGS. 17A and 17B illustrate an example of a conventional aluminum nitride circuit board, wherein FIG. 17A is a plan view and FIG. 17B is a cross-sectional view taken along the line 17B--17B of FIG. 17A. In FIGS. 17A and 17B, a copper plate is bonded to a surface of an aluminum nitride substrate 1 serving as a ceramic substrate so as to form a collector electrode 2. The other surface opposite to the collector electrode 2 is entirely covered with another copper plate so as to form a ground electrode 3. A power semiconductor device such as an insulating gate bipolar transistor (hereafter referred to as an IGBT) 4 is attached to the collector electrode 2. On the aluminum nitride substrate 1, there is also a copper plate bonded to an area adjacent to the collector electrode 2 so as to form an emitter electrode 5. In the final product form, the circuit board is placed in a power module package in such a manner that the ground electrode 3 is connected to a block serving as a heat sink (not shown) or the like. That is, the circuit board, on which the semiconductor device 4 is mounted, is placed in a plastic package, and the inside of the package is filled with a resin such as silicone gel or epoxy resin (not shown) so that the surfaces of the circuit board are covered with the resin.
FIG. 18 illustrates an example of a production process flow of a circuit board according to a conventional technique. In this specific example, an electrode pattern is formed by means of etching. First, an aluminum nitride substrate 1 is prepared. A soldering material to be used to bond copper plates 6 and 7 to the aluminum nitride substrate 1 is printed on the surfaces of the aluminum nitride substrate 1. The thickness of the copper plates 6 and 7 is typically of the order of 0.3 mm. Copper plates 6 and 7 are placed on the aluminum nitride substrate 1 and heated at a high temperature so that these copper plates 6 and 7 are bonded to the aluminum nitride substrate 1. A resist 8 is then coated on both surfaces, and exposed to light so as to form a predetermined pattern in the resist. After developing the resist, the copper plates are etched using the resist pattern as a mask so as to remove unnecessary parts of the copper plates. The surfaces of the copper electrodes are polished, and plated with Ni. Thus, a complete circuit board is obtained.
FIG. 19 illustrates another example of a production process flow of a circuit board according to a conventional technique. In the previous example described above, the electrode patterns are obtained by etching the copper plates 6 and 7 which have been previously bonded to both surfaces of the aluminum nitride substrate 1. In the present example, unlike the previous one, copper plates are first formed into predetermined patterns and then bonded to a ceramic substrate. The patterning of copper plates into electrode patterns can be performed by means of punching or etching. After the patterning process, a soldering material for use to bond the electrode patterns to the ceramic substrate is coated on the ceramic substrate. The copper electrodes are then placed on the ceramic substrate, and heated at a high temperature so that the copper electrodes are bonded to the substrate. Thus, a complete circuit board is obtained.
When an IGBT is in an on-state, a high current of the order of 100 A flows through the IGBT. On the other hand, when the IGBT is in an off-state, a high voltage of the order of 2 kV or greater is applied to the IGBT. Thus, a high voltage appears between the collector electrode 2 and the ground electrode 3 on the circuit board. Therefor, a circuit board for mounting a power semiconductor device such as an IGBT should meet the following requirements:
1) The circuit board should have as good heat removal characteristics as possible to prevent the increase in temperature. To achieve this purpose, aluminum nitride having a high thermal conductivity is preferably employed as the substrate material.
2) The copper plates and the aluminum nitride substrate should be thin enough to prevent generation of cracks during heat cycles due to stress caused by the difference in expansion coefficients of the copper plates and the substrate.
3) The electrode patterns of the circuit board should be designed so that no discharge occurs at any portion of the electrode patterns during operation of the semiconductor device.
As a result of recent advances in semiconductor device technology, a circuit board for mounting a semiconductor device designed to operate at a voltage greater than 3 kV has been required. The increase in operating voltage of semiconductor devices has brought about problems of dielectric breakdown and partial discharging, which are not significant problems in conventional circuit boards. These problems cause a great reduction in reliability of circuit boards. The partial discharge refers to a discharge that occurs at a localized portion of a circuit board where a high electric field is concentrated. The partial discharge generates noise which can cause a semiconductor device mounted on a circuit board to operate in an erroneous manner. If partial discharge continues for a long time, degradation occurs in an insulating material, which can finally result in dielectric breakdown. If dielectric breakdown occurs in a circuit board, an apparatus or system including that circuit board can no longer operate in a correct manner. Thus, with the increase in the operating voltage of semiconductor devices, there is an increasing need for a circuit board having a high dielectric breakdown voltage and also having a high partial discharge voltage.
In conventional circuit boards, semiconductor devices mounted thereon are not operated at a very high voltage, and thus the partial discharge is not a significant problem. Therefore, the partial discharge is not taken into account in the design of the conventional circuit boards. The inventors of the present invention have investigated the effects of the partial discharge on the circuit board. First, the voltage at which a partial discharge starts was measured for conventional circuit boards whose patterns were formed by means of etching. In the case of an aluminum nitride substrate having a thickness of 1.0 mm, a partial discharge was observed to start at a voltage as low as about 5 kV. To find the cause of the low starting voltage of partial discharge, the cross-section at an end of the electrode pattern was observed. The observation has revealed that the electrode pattern 2 has a very sharp edge 2a in a portion in contact with the ceramic substrate 1 as shown in FIG. 20. In the case of a copper electrode pattern having a thickness of 0.3 mm on an aluminum nitride substrate having a thickness of 1.0 mm, the radius of curvature of the sharp edge 2a is as small as 0.01 mm. Since the electrode 2 has a certain finite thickness, the electrode 2 has another sharp edge 2b on the side opposite to the sharp edge 2a in direct contact with the substrate 1. The etching process generally occurs in an anisotropic fashion, and thus the copper pattern is etched not only in a direction across its thickness but also in a lateral direction. As a result, the etched copper pattern has a sharp edge in cross section in a portion in contact with the ceramic substrate 1. This phenomenon is well known in the art as described for example in Print Circuit Board Handbook, Second Edition, Completely Revised, Japan Print Circuit Industry Association, 1987. However, little has been known about the magnitude of the electric field at the sharp edge and its effect on the discharge. To obtain knowledge about these, the inventors of the present invention have performed numerical analysis on the electric field at the sharp edge 2a in contact with the substrate 1. The result shows that a very high electric field can occur at such a sharp edge. When a high voltage, for example 5 kV, is applied to the electrode 2, the maximum electric field near the edge 2a can be as large as 80 kV/mm. This high electric field near the edge 2a causes a reduction in the starting voltage of partial discharge. Thus, the analysis has shown that the low starting voltage of partial discharge in the conventional circuit boards is due to the concentration of the electric field at the sharp edge of the electrode pattern.
In an electrode pattern on the conventional circuit board, as described above, a very sharp edge is produced at an end portion in contact with an insulating substrate. The sharp edge of the electrode facing the ground electrode causes a concentration of lines of electric force at that edge, and thus a high electric field is produced there.
A discharge occurs in a gas space near the sharp edge of the electrode pattern. This means that if the gas space, in which a high electric field is present, is eliminated, then the circuit board will have a higher starting voltage in discharge. To eliminate the gas space, the circuit board is usually housed in a case filled with a silicone gel 9 as shown in FIG. 21. However, in some cases, a small void 10 is produced in the gel 9. The electric field in the void 10 is generally higher than that in the dielectric surrounding the void 10. Therefore, if such a void is present near the pattern electrode 2 where an electric field is concentrated to a high level, a discharge is induced more easily, which results in a reduction in the reliability. Thus, the generation of such a void 10 in a gel 9 in a high electric field region is another problem in the conventional circuit boards.

Circuit board with conductor layer for increased breakdown voltage


The invention discloses a process to implement and maintain water bodies larger than 15,000 m3 for recreational use, which comprises the following steps:    a.—providing a structure able to contain a large water body larger than 15,000 m3;    b.—feeding the structure of step (a) with inlet water;    c.—measuring water pH;    d.—adding an oxidizing agent to the water contained in the structure of step (a),    e.—adding a flocculating agent in concentrations within 0.02 and 1 ppm with maximal frequencies of 6 days and cleaning the bottom of the structure of step (a) with a suction device to remove precipitated impurities from the bottom of said structure, and;    f.—generating a displacement of surface water containing impurities and surface oils by means of the injection of inlet water according to step (b), which generates said displacement in such a way to remove said surface water arranged in the structure of step (a), which together with step (e) replaces traditional filtering.

When a nutrient enters into water, aerobic organisms consume dissolved oxygen as a result of the induced metabolic activity. Thus, the nutrient exerts a demand on dissolved oxygen availability, which is called biological oxygen demand (BOD). If the amount of organic material in the medium is very high, it can lead to a decrease in dissolved oxygen concentration. At low oxygen levels, aquatic environment promote the growth of anaerobic species.
Anaerobic metabolism is much slower than aerobic processes (typically more than one order of magnitude) have lower efficiency, and generates various intermediate organic compounds (e.g. organic acids, alcohols, methane). As a result of the lower rate of dissolved organic matter consumption, this will accumulate in the aquatic environment.
If dissolved oxygen is consumed faster than it can be replenished, water starts to deoxygenate. No strictly aerobic organism, from microorganisms to fish, will survive in said water. Thus, organic contaminants will accumulate and further establish anaerobic conditions, which generate malodorous substances (e.g. sulfides and volatile amines) and partially oxidized organic compounds.
In addition to bad smell, anaerobic conditions can raise human health issues, because many anaerobic bacteria are pathogenic (for instance, tetanus, and botulism). When the water contains dissolved sulfates, reducing anaerobic bacteria produce H2S (corrosive and poisonous).
The increase of the amount of nutrients required for life in a water body is called eutrophication. Eutrophication is defined as the process of nutrient enrichment in a water body. It is a natural phenomenon in the ageing process of ponds and lakes (eutrophic lakes). On the contrary, a young water body, poor in nutrients required for life, is called oligotrophic. The nutrient increase in the pond promotes a higher production of aquatic plants and animals. Said organic matter increase generates in its turn an increase of the organic content of sediments. Eutrophication can generate serious problems in superficial water bodies.
Photosynthesis implies the creation of organic matter from inorganic materials and therefore the production of large amounts of organic substances where there were only little amounts before. When algae/plants die, their components are transformed in organic nutrients that exert an oxygen demand.
During photosynthetic action, CO2 is readily consumed, thus producing a rise in pH, which can attain a value over 10. During the night, the inverse reaction occurs, consuming oxygen and generating CO2, with which pH tends to drop. Photosynthetic activity has a significant effect on the pH level of the water body, because it affects the reversible reaction.HCO3−+H+← - - - →CO2+H2O
Finally, the masses of algae deposited in the shore die and rotten, thus producing anaerobic conditions, which present health dangers (e.g. formation of Clostridium botulinum, a strictly anaerobic pathogen microorganism). On the other hand, aquatic plant ramifications retain organic solids that decompose, which exerts a concentrated oxygen demand.
Generally, nitrogen N and phosphorus P are the limiting factors. In microorganism growth, P is consumed as phosphate, while the major part of bacteria assimilate N under the form of NH3, and only some of them assimilate N as NO3−. Inversely, algae assimilate N as NO3− and very few use NH3. There are more bacteria able to use NO3− as oxygen source than as N source. According to the approximate stoichiometry of photosynthesis in algae, N:P ratio is in the order of 7:1. According to the Liebig minimum law, an N:P ratio much higher than 7 in a water body indicates that P is the limiting nutrient; on the other hand, an N:P ratio value much lower than 7 implies an N limitation. Some authors suggest that P and N concentrations higher than 0.015 and 0.3 mg/l, respectively, are enough to generate an excessive growth of algae in lake waters.
The main sources of organic N are proteins, amino acids and urea; on the other side, inorganic N is in the form of NH3, NO3−, NO2−. Ammonia is a characteristic product of organic matter decomposition, and it can be microbiologically oxidized to nitrites and nitrates by the action of nitrifying bacteria. These processes occur naturally in water and constitute a major contribution to the biological oxygen demand.
When artificial water bodies are formed, such as lakes or ponds, water quality deteriorates progressively. Depending on the nutrient contribution, it can be reached any state from equilibrium in which algae, aquatic plants, bacteria, insects and fish survive in stable condition to eutrophication processes in which the excessive contribution of nutrients produces a high proliferation of algae and aquatic plants. When these die, they are decomposed by bacteria in aerobic processes that consume the oxygen. When oxygen decreases, many organic remainders remain deposited in the bottom, thus increasing sediments and suffering processes that increase turbidity, bad smells are produced and the physicochemical and sanitary quality of the water is impaired, which reduces the possibilities of recreational use.
To mitigate these effects different techniques are used, such as aeration systems to increase oxygen levels, algaecides and herbicides to control the excessive proliferation of algae and aquatic plants, the use of biological filters to decrease nutrient contribution, fish and zooplancton to reduce algae, nutrient capture by means of chemicals, inoculation of bacteria to digest organic matter, colorants to improve the aesthetic appearance, mechanic removal of algae and aquatic plants, the use of dredges to decrease the amount of sediment, clarifying agents to decrease turbidity, etc.
The characteristics and quality of the water of these ponds are very different to those of swimming pools. In the first case, an ecological equilibrium between different species must be attained, while in the second case the objective is the removal of organisms and impurities. Therefore, very different turbidity, color and physicochemical characteristics standards are accepted.
To keep swimming pool water transparent and apt for bathing, filtration systems are used, mainly sand, diatomaceous earth and cartridge filtration systems. The entire water must be filtered every 4 to 12 hours, depending on the type of swimming pool.
In addition, organic matter oxidants, disinfectants, algaecides and eventually pH regulators and clarifiers must be used to keep aesthetic and sanitary conditions. Depending on each country's regulation, swimming pools are required to keep minimal disinfectant residual concentrations or permanent redox potential (ORP) levels between 650 mV and 750 mV.
The application of the swimming pool technology to large water bodies to obtain optimal water quality is not possible due to the high cost of the installations and the involved operative costs.
To illustrate this situation, we can recall that if the water body to be filtered is the one described below in the application example of 250,000 m3, complying with the minimal regulations of Chilean Swimming Pools (T=2 en NCh 209, example country for the application), 2,983 liters per second are required to be filtered, which corresponds to the water volume treated by a potable water plant for a city. An Olympic swimming pool has 2,500 m3 (50×25×2 m), which corresponds to 1% of the considered volume in the application example of this patent application.
The same is true when swimming pools chemicals are to be applied to these volumes. The water volume of the application example of this invention corresponds to 4,000 10-meters-long swimming pools.
The control of disinfectants in swimming pools and spas by means of the measurement of the (ORP) has been used for many years with good results. ROP measures the oxidizing power of the disinfectant or, in other words, its real concentration-independent chemical activity. Direct measurement of disinfectant concentration can lead to error, because the activity can be decreased depending on pH and the presence of contaminants, even at high concentrations. In fact, studies have demonstrated that bacterial life in water is more dependent on ROP than on oxidant concentration. To remove undesired microorganisms in swimming pools, normally a ROP value between 650 mV and 750 mV is permanently maintained (public swimming pool regulations in developed countries require more than 700 mV permanently) at a normal pH between 7.2 and 7.6. This is not possible with large water bodies due to the high implied costs.
The previously exposed facts make maintaining large water bodies (over 15,000 m3) using filtration and disinfection technologies similar to those of swimming pools for recreational use largely unviable.
Therefore, there are no large artificial ponds or dams with the aesthetic and sanitary characteristics of swimming pools or tropical seas that have clarity levels higher than 25 and even 40 meters.
The technical problem solved with the present invention is the achievement of these characteristics in large water bodies at low cost.

Structure to contain a large water body of at least 15,000 m


An image forming system includes a server, a first image forming apparatus, and a second image forming apparatus. The server includes: a registration unit that stores identification information for the first image forming apparatus in the first memory; a job obtaining unit that obtains a print job; and a job transmission unit that, upon receiving a request including the identification information stored in the first memory, transmits the print job. The first image forming apparatus includes: a second memory that stores the identification information; and a first job reception unit that transmits the request including the identification information stored in the second memory to the server and receives the print job. The second image forming apparatus includes: an identification information obtaining unit that obtains the identification information; and a second job reception unit that transmits the request including the obtained identification information to the server and receives the print job.

1. Field of the Invention
The present invention relates to an image forming system and an image forming apparatus.
2. Description of the Related Art
A print system has been proposed in which a client sends a print job to a server via the Internet, the server sends the print job to a printer via the Internet, and the printer performs printing based on the print job (for example, see Japanese Patent Application Publication No. 2008-146465).
In the print system, plural printers may be connected to the server and receive print jobs from the server to print them.

Image forming system and apparatus usable with the internet in a cloud printing arrangement


A jointing apparatus includes a first laser head which emits a laser beam for adhesive heating and a second laser head which emits a laser beam for welding. In jointing components of a work with a thermosetting adhesive agent, the defocused laser beam is applied to an adhered part for a short time. Thereupon, the adhesive agent is primarily cured so that the components are tacked together. In spot-welding the components, the laser beam for welding that is converged by the second laser head is applied to a spot-welded joint.

1. Field of the Invention
The present invention relates to a component jointing apparatus used to joint components together and a joint structure formed of a plurality of components.
2. Description of the Related Art
A hard disc drive (HDD) that is used to record in or read data from a rotating disc has a disc drive suspension that is attached to the distal end portion of an actuator arm. A head portion that includes a slider is mounted on the distal end portion of the suspension. When the disc rotates, the slider slightly lifts above the disc surface, whereupon an air bearing is formed between the disc and the slider.
The disc drive suspension comprises a load beam, a baseplate provided on the basal part of the load beam, a flexure fixedly lapped on the load beam, etc. The slider is attached to the distal end of the flexure. Further, a hinge member is located between the load beam and the baseplate.
As is described in Jpn. Pat. Appln. KOKAI Publication No. 2001-155458, for example, the disc drive suspension is formed by jointing together a plurality of platelike components, such as the load beam, baseplate, flexure, etc. These components are fixed to one another by spot welding or the like.
Improvement of the response (seek time) of the disc drive requires a disc drive suspension having high stiffness and high natural frequency. With the spread of portable computers, the shock resistance of the disc drive has become an important factor.
In order to enhance the shock resistance of the disc drive suspension or increase the natural frequency, it is effective to reduce the weight of the suspension without lowering its stiffness. To attain this, the components (load beam, baseplate, hinge member, etc.) that constitute the suspension should be formed of materials that suit their respective functions.
In some cases, therefore, the components are expected to be formed of any other materials than metal, cladding materials, or unweldable materials. In general, components of a disc drive suspension are jointed together by laser welding. Depending on the materials of the components, however, laser welding cannot be applied to the jointing.
A proposal has been made to joint the components with an adhesive agent instead of welding them. For example, the components may be jointed with an ultraviolet-curing adhesive agent or thermosetting adhesive agent.
In order to cure the ultraviolet-curing adhesive agent, however, the components should be partially formed having holes through which light passes. Inevitably, therefore, the shape of the components is complicated, and their stiffness is lowered.
If the thermosetting adhesive agent is used, the components should be positioned with respect to one another by means of a jig after the adhesive agent is supplied to those regions of the components to be jointed. Further, the components should be heated in a heating oven for a long time. Since the next process cannot be started while this heating process is being carried out, the operating efficiency is not high enough.
Conventionally, an apparatus for welding and an apparatus for setting the adhesive agent are provided separately. Thus, separate apparatuses must be used to carry out a welding process and a bonding process for a work that has a bonded part to be bonded with the adhesive agent and spot-welded joints in a mixed fashion. In consequence, the processes are complicated and time-consuming.

Jointing method for obtaining a joint structure formed of a plurality of parts


The subject matter described herein relates to implementation of a dictionary in a column-based, in-memory database where values are not stored directly, rather, for each column, a dictionary is created with all distinct values. For each row, a reference to the corresponding value in the dictionary is stored. In one aspect, data is stored in a memory structure organized in a column store format defined by a plurality of columns and a plurality of rows. A dictionary for each column in the memory structure is generated. The dictionary has distinct values for each column. A reference to the dictionary is generated for each column in the memory structure. The dictionary and the reference to the dictionary are stored in the memory structure.

An in-memory database system is a database system that primarily uses main memory for data storage. One example of an in-memory database system is the HANA in-memory database system provided by SAP AG of Walldorf Germany. As opposed to employing a disk storage mechanism for storing business data, in-memory database systems such as HANA use main memory, which is faster than disk-based databases since storage, access and retrieval functions execute far fewer CPU instructions. Accessing data in main memory reduces the input/output reading activity when querying the data, which in turn provides faster and more predictable performance than disk.
Traditional databases are row-based, and for each row, the size of the row in bytes is known and needs to be set aside for storage. For example, the instruction:
Create Table T (City Char (10), Revenue Integer)
Each row will require 10+4 bytes of storage (INTEGER requires 4 byte), and rows with identical values will still require 10+4 bytes per row. Accordingly, a storage estimate is 14 bytes per row, and 42 bytes total, for storing 3 rows. One challenge is to represent the data with small memory consumption, because memory is costly, and less storage means faster access (less memory bus bandwidth).


A method (900) includes delivering a first bias current (IGAIN) to an anode of gain-section diode (590a) and delivering a second bias current (IPH) to an anode of a phase-section diode (590b). The method also includes receiving a burst mode signal (514) indicative of a burst-on state or a burst-on state, and sinking a first sink current (ISINK) away from the first bias current when the burst mode signal is indicative of the burst-off state. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method also includes sinking a second sink current away from the second bias current at the anode of the phase-section diode and ceasing the sinking of the first sink current away from the first bias current at the anode of the gain section diode.

The tunable optical network unit (ONU) is a component widely used in a Time and Wavelength Division Multiplexing-Passive Optical Network (TWDM-PON) system, which serves as the primary architecture for Next-Generation Passive Optical Networks (NG-PON1 and NG-PON2). A tunable transmitter, which is made of a laser and a driving circuit for the laser, is the most critical component in the tunable ONU. Traditionally, Directly Modulated Lasers (DMLs) have been widely used in the TWDM-PON system with wavelength lengths tuned either through Distributed Bragg Reflector (DBR) current or the temperature by Thermoelectric Cooling (TEC) control. However, DML-based tunable ONUs suffer from limited transmission distance because of dispersion. Instead, an Electro-absorption Modulated Laser (EML)-based tunable ONU is preferable because of its superior performance and compact size. Typically, a burst-mode circuit drives an EML. Wavelength stability is a crucial specification for a tunable ONU and the associated burst-mode circuit, as wavelength drift may cause channel cross-talk. Temperature can have a significant impact on the wavelength of the laser. Despite the TEC controlling the temperature accurately at static states, the self-heating effects, introduced by burst-operations, can cause large wavelength drifts, which eventually introduces large Bit-Error-Rate (BER) for the optical system. Moreover, a fast burst time is required to reduce the overhead and increase the bandwidth of the system.

Wavelength drift suppression for burst-mode tunable EML transmitter


A first potential hot trace of a program is determined. A second potential hot trace of the program is determined. A common path from the first potential hot trace and the second potential hot trace is selected as the selected hot trace of the program.

In recent years, there has been increasing interest in dynamic binary translation and runtime optimization. Dynamic binary translation and optimization is a technique that translates and optimizes binary code at runtime for compatibility and performance improvement. The basic idea is to identify the most frequently executed code of a program as a hot trace and optimize the hot trace code based on runtime profiling information.
Typically, a dynamic optimizer monitors a program execution, identifies hot traces within the program, and performs optimizations of these hot traces. The optimized hot traces may be placed in an instruction cache so that subsequent executions of hot traces may be run in their optimized forms from the instruction cache. The performance results of a runtime optimized program depend greatly on the hot trace selection techniques.

Two-pass MRET trace selection for dynamic optimization


A device and method are disclosed for regulated storage capacitor charging to high voltage. The device comprises an AC source configured to output an AC voltage, a voltage multiplier that constitutes a charging unit and a control unit. The control unit is configured to constantly sense the voltage on the storage capacitor and upon detecting that a predefined maximum charging voltage has been reached to react in at least one of the following ways: stop charging the storage capacitor, and closing an output switch so as to discharge of the storage capacitor through some load. The capacitance of each capacitor in the charging unit is substantially smaller than that of the storage capacitor so as achieve accurate maximum charging voltage as well as limited charging current.

There are various circuit models in the art for charging energy storage capacitor (ESC) to high voltage, i.e. above 5 KV. A typical application of these circuits is to generate a short and very strong pulsed electric field (PEF). This PEF is used, for example, to result in an electroporation process in an Electroporation Cell (EPC).
One favorable charging circuit model is disclosed in European Patent Application EP3176246. This prior art publication provides an electric pulse generator for an electroporator including, as a poring pulse generating means: (A) an n-stage Cockroft-Walton circuit; and (B) a branching-merging circuit including (b1) a switching switch that is turned off in a high-voltage mode and turned on in a low-voltage mode; and (b2) a circuit that is m1-series m2-parallel capacitors connected in series to the output side of the switching switch. However, in this publication there is no mention of how to adjust the amplitude of the generated pulse.
Thus, it would be desirable to provide a simple to implement technique for ESC charging when high amplitude PEF is required, when accurately adjustable amplitude is required as well as limited peak EPC charging current.

Regulated storage capacitor charging device and method


A system that limits the torque of motors and discontinues motion control activity of system components in order to protect electrical and mechanical system hardware. Mechanical stresses are controlled by a microprocessor in a manner that they will not exceed predefined limits so that mechanical components will not be destroyed. Thus, replacement of major system components such as drive electronics and fuses may be avoided. Hence, there will be a reduction in service calls to repair the motors and system components.

Electric motors receive electrical energy and convert the electric energy into mechanical energy or torque. The rotary direct current electric motor delivers mechanical power by means of a rotating shaft extending from one or both ends of its enclosure. When a rotary direct current motor is first connected to an electric supply, there is a large surge of current because nothing in the motor opposes the flow of current except the armature resistance, which is very low. As the motor accelerates the counter emf increases which causes the armature current to decrease. The current decreases as the motor accelerates until a point of equilibrium is reached where the current drawn by the motor from is the power source just balances the requirement of the driven load at a constant speed.
As long as the motor-driven load remains constant, the motor speed remains constant. If the load on the motor is increased, the motor speed decreases. This decrease in speed causes a decrease in the counter emf, which in turn allows the motor to draw more current from the power supply, which in turn causes the motor to develop more torque to carry the increased load at a slightly lower speed. If the motor load continues to increase, the motor will continue to develop additional torque and continue to slow down. As the load continues to increase the motor will have to be turned off to prevent damaging the motor. The prior art utilized electrical circuit breakers like fuses to protect electrical devices from excessive currents. In a typical fuse, there is a time delay between the first sensing of the high current and the blowing of the fuse. The blowing of the fuse caused the motor to stop. Thus, a problem with the prior art was that intervention would be required for the fuse to blow and time would be required to replace the fuse.
Prior art Motor systems employed in paper handling equipment used a Positive Temperature Coefficient resistor (PTC) or a Polyfuse to control excessive current. The positive temperature coefficient resistor was placed in series with the motor and acted somewhat like a fuse. If the Motor stalled, the current drastically increased and the PTC heated up. When the PTC heated up, the resistance increased, which caused the current to decrease, thus preventing the motor from becoming a fire hazard. The use of PTC type devices also eliminates the need to replace fuses. Since the motor can be shut off, the PTC device cools and the motor can be returned to normal service.
If a paper jam would occur in paper handling equipment that utilized PTC type devices and fuses, typically it would take too long for the PTC device to heat up and limit the current before the fuse would blow. The foregoing was true even if a slow blowing fuse with a time delay was used. Thus, a simple paper jam may necessitate a service call to repair the damage.
Many different types of systems utilize electric motors to move material through the system, i.e., photocopiers, integrated mailing systems, etc. The above systems utilize closed-loop motion control circuits to monitor and control the torque of individual motors. The torque limiting was accomplished by utilizing analog set points and analog circuitry to measure the current required by the motor. If the current exceeded a preset threshold, the torque limiter would reduce the current or turn off the motor.
A disadvantage of the foregoing is that the system was inflexible, since the system was dealing with fixed set points. The above system would turn off the motor when the set point was reached, regardless of the existing machine or motor operation. The system may turn off the motor when the motor should not be turned off, i.e., the set point was set too low. The above system was also subject to false triggers from transient currents. Furthermore, if the current thresholds were set too high, the drivers could fail and the fuse protecting the circuit could blow, necessitating a service call to repair the motor or machine.

Intelligent torque limiting through current sensing


A leaf bagger composed of an adjustable planar frame carrying on a lower part. A plate is fixed to the lower frame part define front and rear ramps having front and rear edges extending beyond the lower frame part and lying in a common plane. The ramps thus serve to guide material, such as leaves, moved horizontally into a horizontally disposed bag whose mouth is received over the frame and the ramps also serve to support the frame in a vertical position. The plate defining the ramps also be hung vertically on a wall so that the frame is horizontal to receive trash deposited vertically into a bag now carried vertically by the frame.

There are a number of prior patents for leaf baggers consisting of frames which can be inserted into the mouth of the plastic leaf bag to retain the bag open. A typical frame for this purpose is shown in the patent to Barnhart U.S. Pat. No. 4,787,753 where the bag mouth is first threaded through an inner frame then folded back over the frame with an outer frame trapping the folded-over part of the bag between it and the first frame. A major problem with this type of frame is that there is no means other than a user's hand for supporting the frame in a vertical position which is extremely awkward and inefficient when one tries to rake leaves into the bag with only one hand. Furthermore, bare bag material is located immediately inside the frame where it can be easily snagged and ripped by rake tines, particularly when the rake is under the control of only one hand.
Other baggers are either complex and thus exorbitantly expensive as, for example the wheeled bagger shown in the patent to Pravettone U.S. Pat. No. 4,357,728, or lack ramps while exposing the bag to damage as in the patent to Wolf U.S. Pat. No. 4,704,246, or have parts which are easily struck by the rake as in Dieter U.S. Pat. No. 4,530,533.
Furthermore, little thought has been given to making use of the baggers for collecting trash in that long period of the year between leaf falls.


Among six follower balls (5) aligned on the input shaft (7), the two balls (5) situated on one end side (A) always engage tightly with one engagement surface (10a), while the other two balls (5) situated on the other end side (B) always engage tightly with the other engagement surface (10b). This regulates the movement of the balls (5) against the engagement surface (10a, 10b) of the cammed streak portions (10) so as to eliminate a backlash played between the balls (5) and the cammed streak portions (10). This makes it possible to prevent the meshing noise from being induced so as to implement a low noise operation. With the point-to-point contact maintained between the cammed streak portions (10) and the balls (5), it is possible to reduce a friction therebetween, thereby improving a torque transmissibility against the follower wheel (4) to insure a smooth rotational movement with a higher precision.

Speed reducer devices have been applied to robot techniques in which various component parts are transferred during manufacturing processes (e.g., producing digital versatile disks (DVD)). In the speed reducer devices, upon implementing the power transmission, an output shaft is reduced at its speed by driving the input shaft which is connected to a brachiate arm. The speed reducer device is known as a worm wheel device which has a transmission mechanism in which balls are provided between a worm screw and a wheel (referred to e.g., Japanese Laid-open Patent Application No. 6-109081). The worm screw has a series of helical grooves defined as thread helices, and the wheel has semi-circular cavities in which the respective rolling balls are provided.
The worm screw transmits its rotational movement to the wheel by way of the rolling balls, thereby avoiding a backlash played between the worm screw and the wheel so as to insure a low friction and high transmissibility therebetween.
In the worm wheel device disclosed by the Japanese Laid-open Patent Application No. 6-109081, the helical grooves of the worm screw represent the cammed grooves into which the semi-spherical portions of the respective balls are always fit in a surface-to-surface contact. Upon transmitting the rotational movement of the worm screw to the wheel while meshing the balls with the cammed grooves, the cammed grooves slide its concave surface along the spherical surface of the balls so as to implement a torque transmission between the worm screw and the wheel.
It is disadvantageous to slide the cammed grooves along the balls in the surface-to-surface contact from the point of inducing the friction between the cammed grooves and the balls. In order to implement a point-to-point contact instead of the surface-to-surface contact, it is necessary to provide the input shaft with streaks of cammed rib instead of the cammed grooves. In the ribbed cam structure in which the ribbed cam has a jutted portion, the cammed rib comes to engage with the balls to establish a pushable force in association with the rotational movement of the input shaft. This causes to induce a backlash played at an engagement surface between the cammed rib and the balls due to the mechanical reason.
Therefore, it is an object of the invention to overcome the above drawbacks, and provide a ball type speed reducer device which is capable of eliminating a backlash when the cammed rib structure is adopted to engage cammed ribs (jutted streaks) with balls in a point-to-point contact.
It is other object of the invention to provide a ball type speed reducer device which is capable of avoiding a meshing noise when engaging the cammed ribs with the balls so as to implement a low noise operation, while at the same time, improving a torque transmissibility against a follower wheel to insure a smooth rotational movement with a higher precision.


The present invention provides a dual-beam apparatus which employs the dark-field e-beam inspection method to inspect small particles on a surface of a sample such as wafer and mask with high throughput. The dual beam apparatus comprises two single-beam dark-field units placed in a same vacuum chamber and in two different orientations. The two single-beam dark-field units can perform the particle inspection separately or almost simultaneously by means of the alternately-scanning way. The invention also proposes a triple-beam apparatus for both inspecting and reviewing particles on a sample surface within the same vacuum chamber. The triple-beam apparatus comprises one foregoing dual-beam apparatus performing the particle inspection and one high-resolution SEM performing the particle review.

1. Field of the Invention
The present invention relates to a charged particle beam apparatus which employs a scanning electron microscope (SEM) to inspect or observe particles and/or defects on a sample surface. More particularly, it relates to a low-voltage scanning electron microscope (LVSEM) for inspecting uninvited particles and/or defects on surfaces of patterned wafers or masks in semiconductor manufacturing industry.
2. Description of the Prior Art
In semiconductor manufacturing industry, uninvited particles sometime appear and remain on surfaces of masks and/or wafers during semiconductor fabrication process for some reasons, and they impact yield to a great degree. To monitor and therefore ensure the yield, optical apparatuses or called optical tools which are typically based on microscopy have been employed to inspect the particles after some fabrication processes because of their high inspection throughputs and good detection efficiencies. As integrations of IC chips are required higher and higher, critical dimensions of patterns on wafers and masks are shrunk, and consequently smaller and smaller particles will become killers in the yield. On development trends, optical tools are losing their abilities to detect such killer particles due to their longer wavelengths compared to particle dimensions.
Theoretically, an electron beam (e-beam) has a relatively shorter wavelength (such as 0.027 nm/2 keV) compared to particle dimensions (down to several nm), and therefore can provide higher detection sensitivity for small particles than an optical beam. Higher detection efficiency comes from higher detection sensitivity. Conventional e-beam apparatuses or called e-beam tools for inspecting defects on wafer/mask, which are based on Low-voltage Scanning Electron Microscopy (LVSEM) with the normal incidence, can therefore directly perform particle inspection but still be criticized in detection sensitivity and throughput.
To get a high detection sensitivity and high inspection throughput in particle inspection, a dark-field e-beam inspection method is proposed in the cross reference. The dark-field e-beam method employs the difference between the irregular scattering on particles and regular scattering on a sample surface due to an illumination of a primary electron (PE) beam. A dark-field backscattered electron (BSE) imaging, which has a high contrast due to the particles, can be obtained by specifically arranging oblique illumination of the PE beam, collection of backscattered electrons (BSEs) and guiding secondary electrons (SEs). FIGS. 1A and 1B schematically illustrate the formation of the dark-field BSE image. In FIG. 1A, a primary electron (PE) beam 1 passes through a hole of an electron detector 3 and illuminates a sample 2 by an oblique incidence. Consequently, BSEs and SEs are generated and emitted from the illuminated area. Most of the BSEs due to the sample surface travel to the reflection side, and most of the BSEs generated due to the particle 21 moves towards the incidence side and are collected by the detector 3. The electrode 4 attracts the SEs 12 to prevent them from being collected by the detector 3. In other words, the detector 3 only detects the dark-field BSEs 11 which comprise a minority of the diffusely scattered BSEs from the sample surface and most of both the diffusely scattered BSEs and the reflection-like scattered BSEs from the particle 21. In FIG. 1B, the detection signal S3 of the detector 3 is increasing from a low value S3_0 to a high value S3_1, as the PE beam 1 approaches the position P1 of the particle 21. The particle 21 will be shown in the scanning image with a dark background and a high contrast and therefore can be detected out easily.
For a sample with surface trenches or called patterned sample, an e-beam apparatus, which comprises only one single-beam unit employing the foregoing dark-field e-beam inspection method (simply expressed as single-beam dark-field unit hereafter), is only adequate to detect particles inside trenches which are orientated almost parallel to the incidence plane (formed with the surface normal) of the PE beam 1. For the sample 2 in
FIG. 2, one single-beam dark-field unit with an oblique incidence in XOZ plane can detect the particle 21-2 inside the trench 22-2 along the X direction, not the particle 21-1 inside the trench 22-1 along the Y direction, as shown in FIGS. 3A˜3C. As the trench 22-1 lowers the particle 21-1 almost below the surface of the sample 2 in FIG. 3A, the PE beam 1 can only hit the top of the particle 21-1 and consequently the dark-field BSEs 11 disappear. In FIG. 3B, the trench 22-1 is so deep that the PE beam 1 can not hit the particle 21-1 at all. In FIG. 3C, although the trench 22-2 is so deep that the particle 21-2 is much lower than the surface of the sample 2, the PE beam 1 can travel along the trench 22-2 and hit the particle 21-2 from bottom to top as usual.
Accordingly, an e-beam apparatus, which can especially inspect small particles on a patterned sample surface with high detection efficiency and high throughput, is needed. In addition, it will benefit the yield management in semiconductor manufacturing to a great degree if the e-beam apparatus can observe or review the detected particles within the same vacuum chamber as well.


A chimeric protein is provided which comprises a target protein and has been designed so as to be easily cleaved by a processing enzyme, permitting a target protein to be efficiently recovered. The chimeric protein is represented by the following formula: EQU A-L-B. wherein A represents a protective peptide;. B represents a target peptide; and PA1 L represents a linker peptide having the sequence X.sub.1 -X.sub.2 -(Pro, Lys, or Arg)-Arg, wherein X.sub.1 and X.sub.2 represent any amino acid, in its C-terminal region and a domain rich in His in its N-terminal region.

1. Field of the Invention
The present invention relates to a chimeric protein serving as a substrate in the production of a physiologically active peptide or a precursor thereof, and a process for producing the physiologically active peptide or a precursor thereof. Further, the present invention relates to a method for separating the physiologically active peptide from the chimeric protein to purify the physiologically active peptide.
2. Related Art
A number of peptide production processes utilizing the expression of a chimeric protein have been attempted. In this case, chemical or enzymatic cleavage is used for separating a target peptide. Enzymes used in this method include lysyl-endopeptidase (Achromobacter protease I) for specifically cleaving the peptide bond on the C-terminal side of a lysine residue and Staphylococcul protease V8 for specifically cleaving the C-terminal side of a glutamic acid. Chemical methods include cleaving of an asparagine residue by nitrous acid and cleaving of a methionine residue by CNBr.
For the chemical methods, the modification of the target peptide is unavoidable, necessitating the separation of the target peptide from various analogues in the purification of the target peptide after cleaving. On the other hand, for the enzymatic cleaving method, the specificity is high, and the cleaving is performed under relatively moderate conditions, facilitating the purification of the target peptide. Since, however, whether or not enzymes are usable depends upon the amino acid sequence of the target peptide, existing proteases cannot be always used, leading to a demand for universal cleavage enzymes.
When a peptide hormone or a precursor thereof is produced in an organism, a precursor polypeptide for the peptide is specifically cleaved by an enzyme (a processing enzyme). Examples of such enzymes known in the art include a prohormone enzyme 1/3 (PC 1/3), a prohormone enzyme 2 (PC 2), and furin. Kex2 protease which functions in the production of an .alpha.-mating factor of Saccharomyces cerevisiae is also a kind of the above enzyme. When these processing enzymes are used for excising a target peptide from the chimeric protein, it is expected that the peptide hormone is not damaged and the processing enzymes is applicable to a wide variety of peptides. Therefore, the development of such production methods has been desired in the art.
The present inventors have reported a method which comprises providing a polypeptide, derived from E. coli .beta.-galactosidase, as a protective peptide, selecting a proper linker peptide, and efficiently producing a chimeric protein with a target peptide, as an insoluble inclusion body (Japanese Unexamined Patent Publication (Kokai) No. 5-328992). This chimeric protein is solubilized with a modifier, such as urea, and used as a substrate for processing enzymes.

Method for cleaving chimeric protein using processing enzyme


A system that reduces power consumption in an integrated circuit. During operation the system receives a placement for the integrated circuit. The system then groups registers in the placement into clusters and builds a temporary clock tree for the registers within the placement. Next the system assigns net weights to clock wires in the temporary clock tree and signal wires between the rest of the cells of the circuit, and uses the assigned net weights to optimize placement of the cells of the circuit by minimizing a sum of the weighted costs of the wires, wherein the weighted cost of a wire is a product of the net weight of the wire and the length of the wire.

1. Field of the Invention
The present invention relates to techniques for reducing power consumption in an integrated circuit (IC) chip. More specifically, the present invention relates to a method and apparatus for reducing power consumption of the IC chip by judiciously placing the standard cells in the IC chip.
2. Related Art
Advances in semiconductor technology presently make it possible to integrate large-scale systems, including tens of millions of transistors, onto a single semiconductor chip. Integrating such large-scale systems onto a single semiconductor chip increases the speed at which such systems can operate, because signals between system components do not have to cross chip boundaries, and are not subject to lengthy chip-to-chip propagation delays. Moreover, integrating large-scale systems onto a single semiconductor chip significantly reduces production costs, because fewer semiconductor chips are required to perform a given computational task.
However, as the clock frequency of these systems increases, power consumption also increases. In addition to meeting timing and area constraints, power consumption is becoming an important concern for designers of integrated circuits. Excessive power consumption can cause problems in dissipating heat. Additionally, to prolong battery life used in mobile devices such as laptops, cell phones, PDAs, and MP3 players, power consumption must be reduced.
Power consumption can be divided into several components: net-switching power, leakage power, and cell internal power. Net-switching power is the power consumed when switching a net from one state to another one. At the present time, net-switching power accounts for the majority of the power consumption in an integrated circuit chip.
A large component of net-switching power comes from clock nets because clock nets switch during every cycle. Furthermore, the clock tree has a large load because it drives all of the registers and the clock lines feeding the registers. The power consumed on these clock nets is proportional to k*V2C*f, where k is a constant, V is the supply voltage, C is the capacitance of the net and the load connected to the net, and f is the switching frequency of the signal. As the frequency increases or the capacitance increases, power consumption increases. This net-switching power can be somewhat mitigated by decreasing the supply voltage, but this technique has limitations because as supply voltage is decreased, the transistors will run out of headroom and noise margin. The invention reduces C*f, the product of the capacitance and the switching frequency.
A small amount of power consumption within a cell occurs when a temporary short-circuit path between VDD to ground exists. For instance, when an inverter circuit switches from high-to-low or low-to-high, for a brief time interval during the transition, the pull-up device and the pull-down device are both conducting, which causes the inverter circuit to consume a large amount of power. This power consumption component can be somewhat mitigated by sizing the transistors to trade-off performance for decreased power consumption.
In addition to the power management techniques mentioned above, It is possible to turn off the clock in the unused sections of the chip, which can significantly reduce power consumption. It is also possible to reduce or cut off the voltage supply to the sections of the chip not being used. However, when these sections of the chip are active, net-switching power is still being consumed.
Even if all of the above-described techniques are used, power consumption still remains a problem. Hence, what is needed is a method and an apparatus to reduce power consumption in an integrated circuit chip even further.

Method and apparatus for reducing power consumption in an integrated circuit chip


A barrier fabric composite is provided which comprises:. i) a textile fabric comprising a front surface, a back surface, interstices within said fabric, and a determinable interstitial volume; PA1 ii) a liquid barrier enhancing thermoplastic within said interstices and on said back surface, filling at least 50% of said interstitial volume; and PA1 iii) a liquid barrier enhancing plastic coating, on the back surface of said thermoplastic, having a higher melting point or glass transition temperature (T.sub.g) than said thermoplastic, and capable of withstanding temperatures of at least 350.degree. F. PA1 a) forming a film and fabric composite having a determinable interstitial volume by simultaneously feeding a thermoplastic film and a textile fabric between first and second rollers, wherein said film is heated to a plastic state and forced into interstices in the backside of said fabric by said first roller so as to fill at least 50% of the interstitial volume; PA1 b) applying to the backside of the composite resulting from step a) a liquid barrier enhancing plastic coating having a higher melting point or glass transition temperature (T.sub.g ) than said thermoplastic, and capable of withstanding temperatures of at least 350.degree. F; and PA1 c) drying said liquid barrier enhancing plastic coating.. The composite can be prepared by

Various processes are known to make fabrics liquid resistant. Such processes include treatment by soaps, silicones, or polymers such as vinyl, urethane and various latex coatings. U.S. Pat. No. 5,565,265 to Rubin et al. discloses a polyester fabric which is coated with a composition comprising a nonfluorinated copolymer composition such as acrylic copolymer, an antimicrobial composition and a fluorochemical composition. Although the coated fabric can be transfer printed, the resulting product lacks the hand of a fine fabric and high breathability as measured by air permeability test ASTM D737, perhaps due to a combination of fiber to fiber bonding resulting from copolymer latex padded onto the substrate and penetration of the acrylic backcoating into the interstices between the yarns comprising the fabric.
Fabrics for blocking out light have been produced by a three-pass backcoating process. A white (titanium dioxide-containing) latex is applied onto a fabric substrate, a light absorbing black (carbon black-containing) latex is applied onto the white late, and a second coat of white latex is applied onto the black latex. The white latex coats are applied to prevent the black latex coat from being visible on either side of the fabric. While providing an effective "blockout" fabric, the process requires three passes of backcoating and results in adverse drapability (the desired pleating effect and the way in which the. drape hangs) owing to the thickness of the backcoating layers. Parent application U.S. patent Application Ser. No. 071829,521, filed Jan. 31, 1992 discloses a composite suitable f or use in the manufacture of interior automotive parts, which comprises a surface layer of a textile fabric weighing from 6 ounces per square yard to 24 ounces per square yard said fabric being comprised of fibers made at least predominately (that is containing at least 80 percent) from a synthetic thermoplastic polymer selected from nylon or polyester; and a layer of a thermoplastic film, e.g., polyester/polyurethane having a thickness of from 0.5 mil to 20 mils, said film having b een heat bonded to the textile fabric. The resulting composite is not transfer printable, but retains good "hand" or texture characteristics of its fabric component.
It would be desirable to provide a fabric composite suited for use in institutional environments, which provides the good liquid barrier, cleanability, stretchability and characteristics of a plastic or vinyl material, while further providing cloth-like hand, drape, and printability characteristics. It would also be desirable to provide a "blockout" fabric composite which is economical to produce and which has improved drapability.

Barrier fabric composite and its method of preparation


A two section damper assembly and method of use is disclosed for avoiding stratification of cooled air in an air conditioning system. The damper assembly is especially adapted for use in variable air volume air conditioning systems that include an economizer. During the economizer mode of operation, the building in which the air conditioning system is installed is cooled at least partially with outside air as opposed to cooling solely by mechanical means and the volume of air that is required may be relatively low. The variable two section damper assembly ensures that an adequate volume of cooling air is taken in and that there is adequate velocity of the outside air and return air to ensure mixing of the outside air with the return air in order to avoid the stratification of the supply air that can occur. The damper assembly is variable in the size of the opened area and in the direction that the individual vanes of the damper assembly are set.

So called "rooftop" air conditioning systems have steadily evolved since their introduction in the 1960's for heating and cooling of commercial buildings. Rooftop units are characterized as forced air units that distribute the conditioned air by means of fans, through supply ducts, to each of the ventilated zones of a building. The systems are closed loop systems in the sense that conditioned air is provided to the spaces of a building to cool or heat the spaces, and then is returned by return ducts to the heating or refrigeration system to be heated or cooled again.
The most recent rooftop designs are variable air volume (VAV) systems. VAV systems are designed to operate at a constant supply air temperature, for example, 55.degree. F. The volume of the supply air provided to the ventilated zones of the building is varied in order to satisfy particular cooling or heating requirements. On a hot day, for example, when the zones are fully occupied by people, a high volume of cooled air at 55.degree. F. would be needed to satisfy the cooling requirements. On a cool day, when few people are occupying the building, a substantially reduced volume of cooled air at 55.degree. would be required to meet design cooling requirements. The fans in a VAV system are controlled to vary the volume of conditioned air that is being supplied to the various zones at any given time, thereby keeping the temperature of the zones at a design temperature of, for example, 72.degree. F.
The first VAV air conditioning systems provided all cooling by mechanical means. Thus, the compressor and the evaporator coil were operated frequently in order to cool the air distributed throughout a building. This was true even when the outside ambient air was relatively cool. As ways were sought to improve the efficiency and reduce the cost of cooling air, economizers were designed and installed on air conditioning systems. An economizer is a device that introduces outside air into the system to provide cooling when possible. Since VAV systems always supply air at a constant temperature of nominally 55.degree. F., outside air is effective to assist in cooling at all times that the outside air temperature is less than 55.degree. F.
Outside air is mixed by an economizer in a VAV system with the return air from the building cooling zones. The outside air is provided by the fans as cooled supply air to the ventilated zones in a continuous loop to keep the building at a comfortable temperature of, for example, 72.degree. F. It will be appreciated that, as the temperature of the outside air is reduced, a much reduced volume of outside air is needed to cool the zones to a desired temperature. When the outside air is, for example, 10.degree. F., very little outside air needs to be added to the return air to reduce the return air to 55.degree. F. and to keep the zones at 72.degree. F. In such conditions, the total air flow through the air conditioning system can typically be less than one third of the air conditioning system's full capacity, which occurs during 100% mechanical cooling.
The reduced volume of air flow at the lower outside air temperatures results in a problem called stratification in the supply ducts. This simply means that the return air and the outside air are not mixed together prior to delivery to the cooling zones. When the air in the main supply duct descending into the building becomes stratified, one side of the duct will have return air in it while the other side of the duct has outside air in it. Zones that are supplied off of the "return air" side of the duct receive air that is too warm and such zones are perceived by the occupants as being stale and stuffy. Zones that are supplied off of the "outside air" side of the duct, receive air that is very cool and these zones are perceived by the occupants as being cold and drafty.
The problem of stratification is made worse in the more recent VAV systems that are of a side-by-side' design. Side-by-side VAV systems are designed to have return air enter the rooftop-unit on one side of the unit and the outside air enter on the other side, as opposed to the "over and under" orientation of previous designs. The return air and the outside air each pass through a damper assembly and enter a common plenum, where mixing should occur. Side-by-side designs are preferable in that the air that is directed onto the coils of the evaporator is more uniform in temperature from the top to the bottom of the unit. However, at low air flow rates, the side-by-side design results in the fans drawing the return air and the outside air through the plenum of the rooftop unit in unmixed parallel, side-by-side flows. The air then enters the descending supply ducts in a stratified, unmixed manner. The problem of stratification is further exacerbated as rooftop designs are made wider to add additional cooling capacity. The plenum becomes wider, making it more difficult to effect adequate mixing under low flow conditions.
It is a primary object of the present invention to provide a damper assembly for the economizer of a VAV air conditioning system which accomplishes destratification effectively and efficiently, particularly when the air flow is relatively low.
It is a further object of the present invention to provide such a damper assembly that has a plurality of positionable and controllable sections to effect adequate air flow and mixing under all operating conditions of the air conditioning system operation.
These and further objects of the present invention will become apparent from the following description of the preferred and alternate embodiments.
The present invention provides an air damper assembly for use in an air conditioning apparatus providing conditioned air to a space. The air conditioning apparatus has an outside air portion through which outside air is admitted to the air conditioning apparatus and a return air portion through which return air is admitted to the air conditioning apparatus. The air conditioning apparatus is selectable between a mechanical cooling mode of operation during which the cooling is provided by mechanical means and an outside air cooling mode of operation during which the cooling is provided by admitting outside air to the air conditioning apparatus. The air damper assembly comprises an outside air damper and a return air damper. The outside air damper is for controlling the admission of outside air to the air conditioning apparatus, having a first outside air damper portion that is closed during the outside air cooling mode of operation and having a second outside air damper portion that is at least partially open during the outside air cooling and mechanical cooling modes of operation. The return air damper is for controlling the admission of return air to the air conditioning apparatus, having a first return air damper portion that is closed during the outside air cooling mode of operation and is selectable between the open and closed positions during the mechanical cooling mode of operation, and having a second return air damper portion that is at least partially open during the outside air cooling mode of operation and is selectable between the open and closed positions during the mechanical cooling mode of operation.
The present invention also provides an air damper assembly for use in an air conditioning system that provides conditioned air to a space. The air damper assembly has a return air admitting portion and an outside air admitting portion. The air damper assembly comprises a return air damper sub assembly for controlling the flow of return air and an outside air damper sub assembly for controlling the flow of outside air. The return air damper subassembly defines a return air aperture through which return air flows. The return air damper sub assembly has a first return air aperture control for controlling the opening and closing of a first portion of the return air aperture and a second return air aperture control for controlling the opening and closing of a second portion of the return air aperture. The outside air damper subassembly defines an outside air aperture through which outside air flows. The outside air damper sub-assembly has a first outside air aperture control means for controlling the opening and closing a first portion of the outside air aperture and a second outside air aperture control means for controlling the opening and closing of a second portion of the outside air aperture.
The present invention additionally provides a method of controlling an air conditioning system that supplies conditioned air to a space presenting an air conditioning demand. The air conditioning system has a return air admitting portion and an outside air admitting portion and an air damper assembly. The air damper assembly has a return air damper subassembly that controls the flow of return air. The return air damper subassembly has a first portion and a second portion. The air damper assembly also has an outside air damper subassembly that controls the flow of outside air. The outside air damper subassembly has a first portion and a second portion. The method of promoting a uniform temperature distribution throughout the air conditioning system comprises closing the first portion of the return air damper subassembly and closing the first portion of the outside air damper subassembly and at least partially opening the second portion of the return air damper subassembly and the second portion of the outside air damper subassembly at times of relatively low outside air flow. The method also comprises at least partially opening the second portion of the outside air damper subassembly and varying the first and second portions of the return air damper subassembly between the open and closed positions as a function of outside air temperature and cooling demand at times of relatively high outside air flow.
The present invention further provides a method of controlling an air conditioning system that supplies conditioned at a set conditioned air temperature air to a space presenting an air conditioning demand. The conditioned air is at least partially made up of outside air. The air conditioning system has a return air admitting portion and an outside air admitting portion and an air damper assembly. The air damper assembly having a return air damper subassembly that controls the flow of return air and an outside air damper subassembly that controls the flow of outside air. The return air damper subassembly has a first portion and a second portion. The outside air damper subassembly has a first portion and a second portion, the method of promoting a uniform temperature distribution throughout the conditioned air comprises the steps of: comparing the outside air temperature to the conditioned air temperature; closing the first portion of the return air damper subassembly and the first portion of the outside air damper subassembly at substantially all times when the conditioned air temperature exceeds the outside air temperature; varying the position of the second portion of the return air damper subassembly between the fully closed and the fully open positions as a function of the difference between the outside air temperature and the conditioned air temperature and the air conditioning demand at substantially all times when the conditioned air temperature exceeds the outside air temperature; and, varying the position of the second portion of the outside air damper subassembly between the fully closed position and a partially open position as a function of the difference between the outside air temperature and the conditioned air temperature and the air conditioning demand at substantially all times when the conditioned air temperature exceeds the outside air temperature.
The present invention yet further provides a method of controlling an air conditioning system that supplies conditioned at a set conditioned air temperature air to a space presenting an air conditioning demand, wherein the conditioned air is at least partially made up of outside air. The air conditioning system has a return air admitting portion and an outside air admitting portion and an air damper assembly. The air damper assembly has a return air damper subassembly that controls the flow of return air and an outside air damper subassembly that controls the flow of outside air. The return air damper subassembly has a first portion and a second portion. The outside air damper subassembly has a first portion and a second portion. The method of promoting a uniform temperature distribution throughout the conditioned air comprises the steps of: comparing the outside air temperature to the conditioned air temperature; varying the positions of the first and second portions of the return air damper subassembly between the fully closed position and at least a partially open position at substantially all times when the conditioned air temperature is less than the outside air temperature as a function of the difference between the outside air temperature and the conditioned air temperature and the air conditioning demand; and, varying the positions of the first and second portions of the outside air damper subassembly between the fully open position and at least a partially open position at substantially all times when the conditioned air temperature is less than the outside air temperature as a function of the difference between the outside air temperature and the conditioned air temperature and the air conditioning demand.

Two section economizer damper assembly providing improved air mixing


An acoustic transformer includes at least one outer boundary wall. A plurality of inner walls are disposed within the outer boundary wall. The outer boundary wall and the inner walls define a substantially annular input opening divided by at least some of the inner walls into a plurality of circumferentially-spaced input sections. Each of the input sections has an inner circumferential side and an outer circumferential side. A substantially rectangular output opening is divided by at least some of the inner walls into a plurality of output sections. Each of a plurality of acoustic paths interconnects a respective one of the input sections with a respective one of the output sections. The acoustic paths maybe identical or individually unique in order to change the both the shape of the acoustic wavefront at the output and the energy distribution.

1. Field of the Invention
The present invention relates to audio speaker systems, and, more particularly, to audio speaker systems including acoustic transformers that transform wavefronts of one shape from primary waveguides into another shape for input into sound disseminating secondary waveguides.
2. Description of the Related Art
Typically, a horn-type loudspeaker consists of a driver coupled to an initial throat section. The geometry of the sound-radiating diaphragm of the loudspeaker driver may be a cone, a spherical dome, a flat piston, or an annular ring-radiating diaphragm.
It is well known that the angle of sound radiation of the loudspeaker driver is dependent on the dimensions of the radiating exit relative to the wavelength of sound that is being generated. When the wavelength of sound is large compared to the dimension of the driver exit, the resulting radiation pattern has a wide angle. When the wavelength of sound is small compared to the dimension of the driver exit, the resulting radiation pattern has a narrow angle.
The walls of a horn can only confine the radiation pattern; the walls cannot widen the pattern. If the pattern of sound radiated from driver is wider than the angle of the horn walls, then the sound from the driver will fill the horn and the horn walls will determine the resulting radiation pattern of the horn/driver combination.
On the other hand, if the pattern of sound radiated from driver is narrower that the horn walls, then the sound from the driver will radiate as a narrow beam through the horn and the resulting radiation pattern of the horn/driver combination will be substantially unaffected by the horn walls. In this latter case, where the angle of radiation from the driver exit is narrower than the desired coverage, several techniques have been used in the prior art.
One technique in the prior art to widen the angle of radiation of the driver exit is to pass the sound from the driver exit through an acoustic-transformer/geometry-transition that changes the shape from a round to a rectangular slot, wherein one dimension of the slot is smaller than that of the driver exit. If the smallest dimension of the rectangular slot is smaller than the wavelength of sound, then the radiation angle from the slot will be wide and the horn walls can control the angle of radiation from the horn/driver combination (see U.S. Pat. Nos. 4,187,926 and 4,308,932).
The transformation from round to rectangular can solve the problem in the direction where the slot is smaller than the driver exit. However, problems may still exist in the direction where the direction where the rectangular slot dimension is larger than the driver exit.
Another technique used in the prior art in addition to the rectangular slot is to apply vanes in the throat that spread out the acoustic energy, widening the radiation angle (see U.S. Pat. No. 4,685,532). The vanes are a brute force approach to spreading the pattern out.
In the former case, where the angle of radiation from the driver exit is wider than the desired coverage, the horn walls can control the angle of radiation from the horn/driver combination. However, for very narrow horn/driver radiation angles, the horn can become long enough to create practical problems. Several techniques have been used in the prior art to narrow the coverage angle in a shorter distance. These effectively use an acoustic-transformer/geometry-transition that transforms from the round driver exit to a rectangular slot wherein the wave front has been tailored to be substantially flat, resulting in a narrow radiation pattern. This may be substituted for the first part of the horn, shortening the overall length. These inventions use path way geometries to delay the arrival of the sound at the center of the rectangular slot, making the wave front at the rectangular slot substantially flat (see U.S. Pat. Nos. 5,163,167, 6,581,719 and 6,668,969).
The above describes horn/driver combinations with symmetric radiation angles. However, a horn may be designed to radiate sound energy asymmetrically, directing more energy out the top of the horn and less energy out the bottom. One technique in the prior art to achieve that is to pass the sound from the driver exit through an acoustic-transformer/geometry-transition that changes the shape from round to a tall slot with a semi-trapezoidal shape that is wider at the top than at the bottom. This geometric transition directs more energy towards the top. The trapezoidal-shaped slot is coupled to horn flares to define the radiation angles of the horn/driver combination. (see U.S. Pat. No. 5,020,630).
For substantially curved and substantially flat wavefronts, the prior art addresses the two extremes as independent devices—devices that are applicable for making the radiation pattern from the loudspeaker driver exit much wider, or devices for making the pattern much narrower. The prior art addresses asymmetrical energy distribution with slots of varying widths.
The propagation of sound in a horn may be described by the one-dimensional horn equation:
                              ∂          2                        ∅                    ∂                  r          2                      -                  c        2                                                ∂            ∅                    ∂                                      ∂            x                                          ∂            x                                            (                  log                                                              S                )              -                  c        2                                                ∂            2                              ∅                          ∂                      x            2                                =  0where the scalar velocity potential, Φ, is described along the x direction, and the cross sectional area of the horn is given by S. The speed of sound c (e.g., the speed of pressure waves) may be defined by:c2=B/ρwhere B is the bulk modulus of a gas (such as air), and ρ is the fluid density of the gas. The acoustic impedance at the throat of a waveguide is determined by the size and shape of the input and output of the device, the expansion function S and the waveguide length. This is a one-dimensional approximation for determining the radiation impedance of an acoustic waveguide. So, for two acoustic paths to have equal impedance they must share the same input and output shape, length, and expansion function.
According to the prior art, when designing waveguides for the purpose of transforming the apparent shape of the source, certain assumptions are made regarding the nature of the source. U.S. Pat. No. 5,163,167, for example, assumes a planar circular isophase wave surface as the excitation for such a waveguide. The term "isophase" means that the sound wave produced would be similar to the sound wave produced by a single piston-like vibrating disk. It can be shown for all electromechanical transducers that there exists a high frequency limit where diaphragm mode shapes and/or acoustic effects produce a non-planar, non-isophase wave front.
What is neither disclosed nor suggested in the art is an acoustic waveguide that does not have the problems and limitations of prior art waveguides as described above.

This patent is subject to a terminal disclaimer.

Equal expansion rate symmetric acoustic transformer


A process for producing a probe-driving mechanism. A laminate of a first and second insulating layer is placed on a support. Electrode layers and piezoelectric layers are successively laminated on the second insulating layer. Part of the support and second insulating layer is removed to form a cantilever.

1. Field of the Invention
The present invention relates to a piezoelectric actuator, a probe-driving mechanism, methods of production thereof, and an apparatus employing the same such as a tunnel current-detecting device and an information-processing device.
2. Related Background Art
In recent years, application of STM technique is investigated in a variety of technical fields including observation and evaluation of semiconductors and high-molecular materials in atomic or molecular order, fine working, and recording apparatus.
In particular, recording apparatuses are required to have large capacity in calculation information and image information of a computor, and so forth, and development of STM technique therefor is more and more strongly demanded. As the result of progress in semiconductor processing technique, microprocessors have come to be miniaturized and computing ability has been improved. Consequently, recording apparatuses are desired to be further miniaturized. To satisfy such requirements, a recording-reproduction apparatus is disclosed which employs a transducer having a tunnel-current-generating probe provided on a driving means capable of fine adjustment of the gap between the probe and a recording medium. This apparatus records information by applying voltage with the transducer to change the work function on the surface of the recording medium, or reads out information by detecting the change of a tunnel current caused by the change of the work function, at the minimum recording area of 10 nm square (Japanese Patent Application Laid-Open No. 63-161552).
Generally, the probes need to be increased in number in order to accelerate transfer and recording of data. In the transfer or recording of data in the aforementioned apparatus, the probes run along the lines of recorded data by adjusting the space between the probe and a recording medium. Since the breadth of the lines of the recorded data is extremely small, stable recording-reproduction cannot readily be achieved owing to the drift caused by the temperature variation of the apparatus, run-out of the probes from the data lines caused by external vibration, and other influences. Accordingly, the respective probes are required to move independently in high speed in a direction perpendicular to the face of the recording medium.
To satisfy such requirement, W089/07256, for example, discloses a cantilever constituted of lamination of piezoelectric material layers 5, 7 and electrode layers 4, 6, 8 as shown in FIG. 6. The cantilever is prepared by forming an insulating layer 11 composed of silicon oxide film, patterning it, and etching anisotropically a substrate 1 to have a bimorph arm 10.
In the above example of the prior art, however, the thickness of the insulating layer 11 needs to be made thin to suppress side-etching of the Si substrate 1 in the etching of the bimorph arm 10 and the insulating layer 11. Thereby, nonnegligible capacitance is induced between the lower electrode 4 and the Si substrate 1, forming an equivalent circuit by connection with another electrode through the substrate as shown in FIG. 7.
Usually, the driving frequency of a cantilever is limited by the resonance frequency determined by the dimension and the layer constitution of the cantilever. In the example of the above prior art, the driving frequency is limited also by the increase of the time constant caused by the capacitance induced by the piezoelectric substance layers 5, 7 and the aforementioned parasitic capacitance. Consequently, the adjustment of the spacing between a medium and the probe becomes impossible and malfunction arises in writing and reading. In a multi-probe construction, difference in lengths of wiring to the driving electrodes for respective probes causes large variation of the parasitic capacitance, which causes variation of the driving characteristics of the cantilever.
If the insulating layer under the electrode is made thick to reduce the parasitic capacity for the purpose of avoiding the above problems, Si is isotropically etched, when the insulating layer 11 is etched, in the side direction in a dimension of ten times larger or more than the thickness of the insulating layer as shown in FIG. 6, which lowers the controllability of the cantilever.

Process for producing a probe-driving mechanism


Liquid precursors containing indium and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and method of depositing a liquid precursor on a substrate are also disclosed.

Compounds of Groups IB, IIIA and VIA, including for example copper indium diselenide (CIS) and copper indium gallium diselenide (CIGS), have been studied as semiconductor materials for a number of thin-film semiconductor applications. One key application is their use as light absorbing materials in solar cell components. The elements, which form these compounds, are relatively common and fairly inexpensive, and when formulated and processed into light absorbing materials (e.g., CIS and GIGS), they are highly efficient in converting solar energy into electrical energy.
Unfortunately, cost effective methods of fabricating these light absorbing materials, especially in the form of thin films, have been elusive and limited at best. Most current fabrication methods of light absorbing materials (e.g., CIS and GIGS) rely on vacuum deposition techniques (e.g., physical vapor deposition), which are generally expensive and labor-intensive.
Recent advances in the thin film technology involve the use of liquid precursors to deposit precursors of light absorbing materials. Liquid precursors for use in thin film deposition represent less expensive alternatives to vacuum deposition technology. Liquid precursors provide distinct advantages over conventional vacuum deposition technology including higher throughput, lower cost and more efficient material utilization. In addition, liquid precursors are compatible with a broader range of substrate types and surface morphologies including very large substrates or those having considerable flexibility.
Liquid precursors are generally formulated to contain a combination of metal and a multinary chalcogenide material each selected, respectively, from the elements of Group IB, Group IIIA and Group VIA, utilizing hydrazine as a solvent. Upon deposition, the liquid precursor converts to a desired solid precursor or a metal chalcogenide through the application of heat. The deposited solid precursor can then be processed through suitable means in combination with other solid precursors to produce the final light absorbing material (e.g., CIS and GIGS).
The use of hydrazine as a solvent is problematic. Hydrazine is a volatile, corrosive liquid that is not only highly toxic and dangerously unstable, but also expensive. Its use is therefore strictly controlled. For the same reasons, hydrazine-containing liquid precursors require special care and handling including implementation of extensive safety measures. Thus, the cost and difficulty of making and using hydrazine-containing liquid precursors presents problems in the industry.

Liquid precursor for deposition of indium selenide and method of preparing the same


An ethylene polymer having. a) a Polydispersity Index, PDI, of about 3 to 9; PA1 b) an nRSI of about 5 to about 18; PA1 c) a cRSI of about 1.1 to 3.0; PA1 d) a Composition Distribution Index, CDI(100), greater than about 45; and PA1 e) a log-viscosity ratio, log(.eta.0/[.eta.]), of about 0.5 to about 1.5 is described. The ethylene polymer has improved processability over conventional linear low density polyethylene.

Wide attention has been given to metallocene catalysts for their ability to make ethylene polymers having relatively narrow molecular weight and comonomer distributions at excellent polymerization rates. Such narrow molecular weight and comonomer distributions contribute to improvements in clarity, toughness, and extractables levels in ethylene polymers having densities much below 0.95 g/cc. However, for some applications requiring processing ease, such as enhanced extrudability, these ethylene polymers can be deficient due to their narrow molecular weight distributions. For example, U.S. Pat. Nos. 5,420,220 and 5,324,800 disclose metallocene-made, linear low-density polyethylenes having characteristic narrow molecular weight and comonomer distributions, along with the associated limitations in processability.
Unfortunately, if the molecular weight distribution of an ethylene polymer is broadened in order to improve processability, the clarity and impact strength of the polymer diminish. In addition, extractables increase, especially for ethylene polymers having densities much below 0.93 g/cc. To improve the processability of an ethylene polymer while maintaining a narrow molecular weight distribution, long chain branching may be incorporated into the polymer. For instance, U.S. Pat. Nos. 5,272,236 and 5,278,272 and PCT Application No. WO94/07930 describe metallocene-made, very low-density and low-density polyethylene having long chain branch structures that are reported to have improved processability. However, long chain branch structures sometimes promote directional orientation during fabrication leading to an imbalance in mechanical properties and reduced impact and tear resistance. The clarity of fabricated articles such as blown film may also be less than optimum for long chain branched ethylene polymers even with narrow molecular weight and comonomer distributions. It would be advantageous, therefore to identify ethylene polymers having the benefit of long chain branching that maintain good mechanical strength and clarity.
U.S. application Ser. No. 08/611,278 filed on Mar. 3, 1996, now abandoned discloses ethylene polymers having narrow molecular weight and comonomer distributions, and very high clarity. However, these polymers do not possess a high degree of fabrication ease, i.e., extrudability, bubble stability in blown film processing, and melt instability resistance in cast film processing. This is due to their relatively low normalized Relaxation Spectrum Index (nRSI), which ranges from about 2.5 to about 6.5. U.S. Pat. No. 5,527,752 generically discloses catalyst compositions that are complexes of transition metals, substituted or unsubstituted .pi.-bonded ligands, and heteroallyl moieties, which may be used to make these ethylene polymers.
An ethylene polymer having fabrication ease superior to that of the ethylene polymer disclosed in U.S. application Ser. No. 08/611,278 filed on Mar. 19, 1996, now abandoned and yet maintaining good mechanical strength and clarity, has now been discovered. This ethylene polymer has a broadened relaxation time distribution that is defined by its high nRSI and cRSI.

Ethylene polymers having enhanced processing ease

Union Carbide Chemicals & Plastics Technology Corporation


A blast gate assembly for connecting two hoses includes a first cylindrical section for frictionally engaging with a first flexible vacuum hose, a second cylindrical section for frictionally engaging with a second flexible vacuum hose, and a valve section disposed between the first cylindrical section and the second cylindrical section. The valve section includes a mounting bracket.

Many woodworking tools, including joiners and planers, for example, create copious amounts of sawdust and airborne dust. Dust collection assemblies have been designed for woodworking to vacuum up dust particles to increase a user's respiratory comfort and allow for clear visibility of the object being worked upon. In some configurations, flexible hoses are used to direct suction capacity from a vacuum source to an end use location. In many woodworking environments, such flexible hoses have a diameter of about 4 inches.
Some woodworking dust collections assemblies are set up as a central vacuum assembly with hoses directed to each of a plurality of end use locations. Valves may be used on each of these hoses to quickly turn the suction on and off at each desired location. One configuration of a vacuum valve is a blast gate configured to connect two flexible hoses end-to-end. In one configuration, a blast gate has an interior sliding panel that is moved between an opened and closed position, as desired by a user. However, because the hoses to which the blast gate is connected are flexible, such panel movement (particularly when done manually) may cause undesirable play in the assembly, which can lead to loosened hose connections, operation difficulty, and stress on the components.