An inverted conical bioreactor is provided for growing cells or microorganisms. The bioreactor has an internal space and a perforated barrier within the vessel, through which a liquid may flow, where cells or microorganisms cannot pass through the perforated barrier. The perforated barrier divides the internal space of the bioreactor into a first chamber and a second chamber. Cells are grown within the second chamber and can be perfused by re-circulating the liquid, for example a growth medium, through the bioreactor. Various inlet ports and outlet ports allow controlling the parameters of flow of the growth medium.

Bioreactors are used to culture microorganisms and isolated living cells, including mammalian and human cells, in a contained and controlled environment. In many cases, the culturing of microorganisms and cells require the microorganisms or cells be physically separated and isolated from the surrounding environment and maintained in a sterile environment. Such cases can include the development and manufacturing of therapeutic microorganisms or cells, such as vaccines and genetically modified cells, and the manufacturing of tools for therapy such as viruses for gene therapy, proteins, antibodies or therapeutic cells. Additionally, the need for containment of the microorganism or cell from the environment could be in cases in which the organism is hazardous.
Culturing and processing of such microorganisms and cells requires several typical steps that might include, but are not limited to, inoculating a bioreactor with a small number of organisms or cells, constantly supplying the microorganism or cells with nutrients, media, supplements, activators, measuring microorganism or cell number, maintaining viability, maintaining identity of the microorganism or cell, maintaining the physical state, and cell collection. During growth and expansion of microorganisms and cells in a bioreactor, it is also important to monitor parameters such as media and glucose consumption, Oxyen, H+ ions in media, conductivity and more. Additionally, long term culturing will usually include transfer of the microorganisms or cells to larger containers as they proliferate. Once the number of microorganism or cells reaches the needed number or activity, the microorganisms or cells are usually processed and formulated. Such processing can include washing of the growth media, concentrating the cells or microorganisms, replacing the media to the final preservation media, or packaging and freezing the microorganisms or cells for further use.
Bioreactors may be used for growing, proliferating, differentiating and maintaining living cells and/or microorganisms for different purposes. Cells grown in such bioreactors are typically perfused by a growth medium, which provides nutrients and oxygen to the cells and removes waste materials and carbon dioxide excreted by the cells. Typically, various steps may be performed before and/or during the culturing of cells or microorganisms in such bioreactors including, for example, selecting cells, culturing cells, modifying cells, activating the cells, expanding the cells (by cell proliferation), washing the cells, concentrating the cells and final formulating of the cells (or microorganisms).
To date, propagation is commonly performed by transferring the medium with the microorganisms or cells between different containers and various tools are used for this purpose, such as larger growth vessels, centrifugation tubes or bags, intermediate storage containers and the final packaging. The above processes may typically include open manipulations were the microorganisms or cells are transferred from one step to the other.
Several of the above indicated steps may require removing the cells from the bioreactor and further subjecting them to steps such as, among others centrifugation, separation, incubation, counting, testing, separation, formulation and packaging. Unfortunately, any steps involving taking the cells or microorganisms out of the bioreactor significantly increase the risk of contamination of the cell by unwanted microorganisms (such as, for example, fungi, bacteria, mycoplasma or other undesired microorganisms) which may adversely compromise the cell culturing process.
There is a long felt need for closed system bioreactors that may reduce or eliminate the need to process the cells or microorganisms by taking them out of the bioreactor and reduce or eliminate the steps and human interaction with the cells during the culture. Furthermore, there is a need to automate and optimize the process end to end by processing the cells from early stages to a final product in one automated and closed system. The bioreactors described herein address these needs and further provide advantageous growth conditions allowing for higher yields and lower media needs.


A method and apparatus for controlling at least one transmission line in a liquid crystal display includes at least one transmission gate. The liquid crystal display includes a plurality of pixels, and each pixel includes a thin film transistor. At least one thin film transistor is connected to the transmission line. The transmission gate has first and second gates, an input and an output. The input is connected to the transmission line. The transmission gate transmits when one of a first voltage of said first gate is greater than a voltage of said input and a second voltage of said second gate is less than said voltage of said input. A first external terminal is connected to the first gate, a second external terminal is connected to the second gate, and a common external terminal is connected to the output of the transmission gate. When the first and second external terminals apply a floating potential, static electricity generated in the transmission line discharges through the transmission gate to the third external terminal. When a low and high voltage are respectively applied to the first and second external terminals, the transmission gate effectively isolates the transmission line. Alternatively, by applying a high and low voltage, respectively, to the first and second external terminals, the transmission line can be pre-charged via the transmission gate with a voltage applied to the common external terminal.

1. Field of the Invention
The present invention relates to a liquid crystal panel for eliminating static electricity generated during the manufacture of the liquid crystal display, and a method of operating the same. More particularly, the present invention relates to a static electricity prevention type liquid crystal panel and a method of operating the same which allows testing of a driving circuit and a pixel section of a driving circuit integrated TFTLCD (thin film transistor liquid crystal display).
2. Description of Related Art
Generally, when manufacturing an LCD panel, static electricity is generated from the upper and lower glass panels of a liquid crystal display panel. If the generated static electricity is maintained, it makes accurately manufacturing the liquid crystal display difficult.
Techniques are suggested in Japanese laid-open patent publications 58-116573 and 63-220289 for eliminating static electricity generated in the liquid crystal panel during the manufacturing process. Since these techniques are described in detailed in the above mentioned publications, the following description of these techniques is provided to discuss problems arising from manufacturing and operating a liquid crystal display device using the above described techniques.
FIG. 1 shows a perspective view of conductive lines of a conventional liquid crystal display for illustrating the conventional method of preventing static electricity as described in Japanese laid-open patent publication 58-116573.
As shown in FIG. 1, a plurality of signal lines G and a plurality of data lines D cross each other to form a cell array. The signal lines are also known as gate lines G. A short conductor ST commonly connects the gate lines G and data lines D so as to maintain the voltage levels thereon at an equal electric potential and eliminate static electricity.
Later in the manufacturing process, the gate lines G and the data lines D are severed according to the dotted line CL. The cut portions of the gate and the data lines G and D are connected to separately manufactured gate driving and data driving circuits (not shown), respectively, to form the liquid crystal panel.
Recently, in order to form a high resolution liquid crystal display panel, a driving circuit and a cell array have been integrated to simplify the manufacturing process and to enhance the reliability of the liquid crystal display device. However, the above described technique for preventing static electricity is not applicable to such an integrated liquid crystal panel for the following reasons.
As shown in FIG. 1, since all of the conductive lines are connected by the short conductor ST, testing of different driving circuits cannot be performed during the manufacturing process.
FIG. 2 shows another technique for preventing static electricity as described in Japanese laid-open patent publication 63-220289.
As shown in FIG. 2, a reference potential line SL is provided external to the region where the gate and data lines G and D are positioned. The reference potential line SL has a certain electric potential value. The source terminals of NMOS transistors 2 are connected to the reference potential line SL, while the gate and drain terminals of the NMOS transistor 2 are connected to an associated data line D. The source terminals of NMOS transistors 4 are connected to the reference potential line SL, while the gate and drain terminals of the NMOS transistors 4 are connected to an associated gate line G. Therefore, the gate lines G and the data lines D are connected to the reference potential line SL through a terminal element of an NMOS transistor. Through the gate lines G and data lines D, a certain voltage generated due to static electricity is input to the NMOS transistors 2 and 4 so as to minimize malfunctions caused by the static electricity.
In the above method, however, if the turn on voltage level is low for the NMOS transistors 2 and 4, currents from the gate and data lines G and D flow therethrough and cause problems for accurately imputing data to the pixels.

Liquid crystal display panel having a static electricity prevention circuit and a method of operating the same


An automatic water regulator apparatus for automatically filling a swimming pool or comparable body of water when the water level is below a predetermined threshold. The water regulator apparatus can be added to any existing built in swimming pool equipped with a skimmer and a water fill line. The water regulator apparatus automatically senses the water level of the swimming pool, establishes if the level is within the allowable range, causes the pool water fill line to turn on if below the allowable range, and subsequently shuts off when the desired water level has been reached. The water regulator apparatus comprises a transmitter assembly and a receiver assembly. The transmitter assembly includes a water level detector which periodically automatically monitors the water level within the pool. If the water level is below a specified threshold, the transmitter assembly sends a radio transmission to be received by the receiver assembly. When the receiver assembly receives the radio transmission, it causes a water fill valve to automatically turn on a water supply to the pool, thereby filling the swimming pool. As the swimming pool is filling, the water level detector monitors the water level until the water level has reached a specified threshold. Once the specified threshold has been reached, the transmitter assembly sends a radio transmission to be received by the receiving assembly. When the receiving assembly receives the radio transmission, it causes the water fill valve to automatically turn off the water supply to the pool.

1. Field of the Invention
The present invention generally relates to the field of swimming pools. More particularly, the present invention relates to the field of automatically activating and deactivating a water supply when the water level in a swimming pool or other body of water is low or high.
2. Description of the Prior Art
Specifically, one of the most common responsibilities associated with pool maintenance is maintaining the proper water level in the swimming pool. Pool water level may fall below acceptable levels due to many factors including evaporation, splashing action, and leakage. If the pool water is too low, the filter will not work properly and may cause damage to the filter which can be costly to repair. In addition, if the swimming pool water is too low, the pool water will not get filtered resulting in stagnation, the pool's sidewall plaster may become stained, and the pool's tile grout may become damaged.
Depending on the swimming pool size, geographical location, time of year (e.g. summer or winter), exposure to sunlight, and amount of use and splashing, a swimming pool may require adding water as much as three times a week, for approximately twenty to thirty minutes per time.
To solve the dilemma of having a water level too low in a swimming pool, pool owners are required to manually turn on the water fill valve to fill the pool, and must subsequently manually turn off the water fill valve once the pool has been adequately filled. The disadvantage of manually turning off the water to the pool is that human presence and labor are required. As a result, pool owners may not be able to take a vacation, since human presence is required to manually add water to the swimming pool. Another disadvantage of manually turning on and subsequently turn off the water to the pool is that the individual may forget to subsequently turn off the pool water once the pool has been adequately filled resulting in the pool being overfilled or overflowing, thereby wasting water.
The following nine (9) prior art patents are found to be pertinent to the field of the present invention:
1. U.S. Pat. No. 3,114,243 issued to Winters on Dec. 17, 1963 for "Automatic System Of Agricultural Irrigation" (hereafter the "Winters Patent"); PA1 2. U.S. Pat. No. 3,726,477 issued to Shapiro on Apr. 10, 1973 for "Automated Irrigation System" (hereafter the "Shapiro Patent"); PA1 3. U.S. Pat. No. 4,133,058 issued to Baker on Jan. 9, 1979 for "Automated Pool Level And Skimming Gutter Flow Control System" (hereafter the "Baker Patent"); PA1 4. U.S. Pat. No. 4,194,691 issued to Birnbach et al on Mar. 25, 1980 for "Automatic Control Of The Moisture Content Of The Soil" (hereafter the "Birnbach Patent"); PA1 5. U.S. Pat. No. 4,197,866 issued to Neal on Apr. 15, 1980 for "Soil Moisture Sampler And Controller" (hereafter the "Neal Patent"); PA1 6. U.S. Pat. No. 4,396,149 issued to Hirsch on Aug. 2, 1983 for "Irrigation Control System" (hereafter the "Hirsch Patent"); PA1 7. U.S. Pat. No. 4,607,399 issued to Yovanofski on Aug. 26, 1986 for "Automatic Pool Water Regulator Apparatus" (hereafter the "Yovanofski Patent"); PA1 8. U.S. Pat. No. 4,621,657 issued to St. Ledger on Nov. 11, 1986 for "Automatic Water Level Monitoring System" (hereafter the "St. Ledger Patent"); and PA1 9. U.S. Pat. No. 5,117,855 issued to Goldsmith on Jun. 2, 1992 for "Automatic Water Control Apparatus" (hereafter the "Goldsmith Patent").
The Shapiro Patent discloses an automatic irrigation system wherein the valves are remotely opened by means of radio signals for operating various irrigation sprinkler valves.
The Baker Patent discloses an automatic pool level and skimming gutter flow control system. It comprises sensor means for sensing the changes in water level and water activity and actuating appropriate mechanical response mechanisms for controlling water feed and skimming gutter drain flow. The system is generally built into the swimming pool upon construction of the pool, or would require substantial installation and expense to add to an existing pool not equipped with the system as it is built into the sidewall, plaster and cement decking of the pool.
The Birnbach Patent discloses an automatic control of the moisture content of the soil. The moisture content of the soil is maintained between predetermined wet and dry thresholds by a control in response to detected thresholds through contacts inserted in the soil to effect the opening and closing of a valve in the conduit by which water is delivered to that area.
The Hirsch Patent discloses an irrigation control system. It comprises masts, soil measurement sensors associated with a lower portion of each mast, data transmission apparatus associated with an upper portion of each mast to transmit data continuously measured by the sensor, and a processing device to process that transmitted data.
The Yovanofski Patent discloses an automatic pool water regulator apparatus. It comprises a pipe opening into the pool through the sidewall and plaster of the pool adequately below the minimum allowable water level of the pool, extending horizontally to supply pool water to two vertical pipes situated away from the swimming pool and which indicate the pool water level. Each pipe has a floating element disposed therein. Each float element has a switch secured to a distal end protruding from the vertical pipes. Brackets are mounted adjacent the switches so that as the float elements rise and fall, the switches are turned ON and OFF thereby activating either pool draining or pool filling devices. The system is generally built into the swimming pool upon construction of the pool or would require substantial installation and expense to add to an existing pool not equipped with the system as it is built into the sidewall, plaster and possibly the cement decking of the pool.
The St. Ledger Patent discloses an automatic water level monitoring system for maintaining a preselected water level. It comprises a chamber in communication with the pool such that the water level in the chamber corresponds to that of the pool. The chamber contains an adjustable overflow tube and a vertically oriented water supply line which has a mechanical diaphragm valve and surrounded by an annular float, where the valve is actuated by a height adjustable overhead actuator bar. The system is generally built into the swimming pool upon construction of the pool or would require substantial installation and expense to add to an existing pool not equipped with the system as it is built into the sidewall, plaster and cement decking of the pool.
The Goldsmith Patent discloses an automatic water control apparatus with a venturi to control water flow over a waterfall. The venturi has a bypass conduit so that the venturi does not act to limit the flow of water to demands made downstream of the water control system. It further comprises a light sensitive control to allow water flow only during day or night by controlling the transmission of the vacuum pulled by the venturi to a porous moisture sensor.
The Winters Patent discloses an automatic system for controlling water on agricultural land.
The Neal Patent discloses a soil moisture sampler and controller. It automatically activates in-ground probes to measure the soil moisture.
It is highly desirable to have a very efficient and also very effective design and construction of an automatic water regulator apparatus for automatically activating a water supply to fill a swimming pool or the like when the water level reaches a certain minimum threshold and deactivating the water supply when the water level reaches a certain maximum threshold. It is desirable that the system does not require installation upon construction of the swimming pool or substantial installation and expense on existing swimming pools. It is also desirable that the system can be easily, efficiently and inexpensively installed by the pool owner to any swimming pool equipped with a water fill line.

Automatic water regulator apparatus for filling a swimming pool or comparable body of water when the water level is low


An image processing system enabling luminance regulation depending on displayed images is provided by a projector, the projector including: a signal input section which input an image signal; a signal output section which outputs a corrected image signal; an image projecting section; a correction table storage section which stores a correction table showing the relationship between a correction amount and a position in an image; an instruction input section which inputs instruction information representing a correction instruction from a user; and a luminance regulating section which corrects a luminance value of the input image signal to make a luminance value in a central portion of an image lower than the current luminance value of the center portion when uniformity improvement of luminance values in central and marginal portions of the image is desired, or corrects that to make a luminance value in a marginal portion of an image lower than the current luminance value of the marginal portion when emphasis of a central portion of the image is desired, based on the correction table and the instruction information.

The present invention relates to an image processing system, projector, program, information storage medium and image processing method which can regulate the luminance value of an image.
In recent years, image display devices such as a projector and the like have been designed to regulate the color and brightness of a displayed image depending on its display contents provided by a movie, game, PC (Personal Computer) or the like.
In such image display devices, the whole image is corrected uniformly.
In fact, however, an appropriate image cannot be displayed by uniformly correcting the whole image since the luminance value in the marginal portion of the displayed image is reduced depending on the properties of light source and projection lens.
For example, Japanese Patent Application No. Hei 4-134914 (Japanese Patent Application Laid-Open No. Hei 5-323892) discloses a uniformity circuit for overcoming such a problem. The uniformity circuit is designed to modulate R, G and B primary color video signals by the use of uneven-color correcting wave-shaped signals, thereby controlling R, G and B beam amperages flowing in CRT to control the luminance output on the CRT phosphor screen. This provides uniform R, G and B illumination distributions on the screen.
However, this uniformity circuit can only suppress the reduction of luminance in the marginal image portion as the result of uneven-color correction. This Japanese Patent Application discloses no concrete technique of correcting the uneven color for suppressing the reduction of luminance in the marginal image portion.
Moreover, it cannot be said that the complete correction of uneven color directly improves the image quality. It is important that the image is regulated depending on the displayed contents, rather than the correction.

Image processing system, projector, computer-readable medium and image processing method


An aqueous dispersion coating for rubber and polymer substrates comprises a blend of a polysiloxane and a curable polyurethane and various additives such as a urethane crosslinking agent, a heat resistant filler, and the like. The aqueous dispersion coating reduces the noise upon contact or movement of the coated substrate with an article and maintains the initial static coefficient of friction therewith over a period of time. A desired end use is as a coating on vehicle weatherstrips such as for doors, trunks, and other enclosing articles.

Heretofore, vehicle weatherstrips while providing a barrier to exterior elements such as wind, rain, snow, and sleet, have generally not diminished, and can even contribute to, the interior noise level of the vehicle. Vehicles thus have had an interior noise level often well above 40 dBA.
Vehicle weatherstrips, such as automotive weatherstrips, have been coated for several years, initially with solvent borne urethane systems and more recently with aqueous urethane systems. While such coatings must pass a variety of automotive performance tests (varies depending upon the Original Equipment Manufacturer (OEM), they generally have an undesirable noise level. Moreover, retention of low coefficient of friction (COF) values is generally not maintained because the coating contains various fillers such as waxes or silicones which migrate to the surface of the weatherstrip and eventually are removed and result in an increased coefficient of friction.
Japanese Abstract 61155432 relates to obtaining a coating composition which, when applied to the surface of a polymeric elastomer such as an object, especially, a nonpolar rubber, allegedly improves the adhesion, lubricity, water repellency, resistance to freezing, abrasion resistance, etc., of the elastomer, by using a curable polyurethane, a curable silicone and a tackifier as the principal components of the coating composition.
Japanese Abstract 61155431 relates to obtaining a coating composition, which, when applied to the surface of an nonpolar polymeric elastomer such as EPT rubber, can allegedly improve its adhesion, lubricity, water repellency, abrasion resistance, resistance to freezing, etc., by using curable polyurethane, a polyorganosiloxane composition and a tackifying agent as the principal components of the coating composition.
Japanese Abstract 61138636 relates to providing a composition containing a curable polyurethane composed of a polyvalent isocyanate and a polyol and a curable silicone as the film-forming elements, giving a firm bond by one-coat treatment, and forming a surface allegedly having excellent slipperiness, water-repellency, sound-proofing property and abrasion resistance.
Japanese Abstract 58071233 relates to preventing friction noise and allegedly improve sliding resistance and adhesion by forming a covering fixing coat using a surface treating agent containing polymer with a specific compounding for polyurethane coating material.
U.S. Pat. No. 6,742,784 relates to a weather strip or glass run for an automotive vehicle. The weather strip comprises a main body formed of an elastomer. A slidably contacting section to which a part other than the weather strip is slidably contactable is fixedly formed on the main body and contains a material having at least one of hydrophilicity and water absorbability. The slidably contacting section may be integral with the main body to form a one-piece structure, in which the slidably contacting section is formed of the elastomer, and the elastomer of the main body and the slidably contacting section contain the material having at least one of hydrophilicity and water absorbability.

Aqueous dispersion coating composition having noise and/or friction abatement properties


Provided is a solid-state imaging apparatus, an electronic device, and a driving method for obtaining an output signal irrespective of temperature-induced changes in characteristics. The solid-state imaging apparatus includes a pixel array section including a first pixel that has a first photoelectric converting section and obtains an output signal with logarithmic characteristics, and a second pixel that obtains a temperature detection signal for detecting temperature, the first and the second pixels being arranged in a matrix pattern, and a correcting section that corrects the output signal on the basis of temperature information obtained from the temperature detection signal.

Logarithmic image sensors have been known that measure output voltage by letting a photodiode operate as an open circuit similar to a solar cell (e.g., see NPL 1).
The logarithmic image sensor in such solar cell mode utilizes a potential difference generated when a current is allowed to flow in the forward direction of a PN junction, i.e., makes use of the relationship of voltage proportional to the logarithm of current. When the voltage in the forward direction of the PN junction is monitored by replacing the current in the forward direction with a photoelectric current generated by photoelectric conversion, the monitoring provides a signal resulting from logarithmic compression of the photoelectric current.

Solid-state imaging apparatus, electronic device, and driving method

SONY SEMICONDUCTOR SOLUTIONS CORPORATION


An oscillator circuit may be used with controller circuits that are designed to operate with crystals, with no modifications to the pinout or firmware of the controller circuit. In some embodiments, the oscillator circuit includes an enable input that is responsive to low-amplitude transitions, which may be coupled to and driven by the crystal output signal of the controller circuit. When transitions are present on the crystal output signal, the oscillator circuit enables its clock output signal. When the controller circuit disables its crystal output signal, the oscillator circuit no longer detects transitions on the crystal output signal coupled to the oscillator circuit enable input, and disables the clock output signal.

1. Field of the Invention
The present invention relates to oscillator circuits, and particularly to oscillator circuits that may be enabled and disabled.
2. Description of the Related Art
Clock generation circuits generally use either a quartz crystal or an oscillator as a clock source. A quartz crystal is a passive, 2-pin component that requires a driver circuit to excite the crystal into resonance, and a receiver circuit to amplify the signal generated by the piezoelectric effect within the crystal, and to generate a useful clock signal. The driver and receiver circuits are frequently embedded within a controller circuit, such as a microprocessor, microcontroller, digital signal processor, network controller circuit, or virtually any digital circuit that utilizes a clock signal. When implemented in this manner, only the crystal is external to the controller circuit, and the remainder of the clock generator circuit is formed within the controller circuit.
Referring to FIG. 1, a clock generator 100 is depicted which utilizes a traditional crystal oscillator circuit. A controller circuit 102 includes a driver circuit 104 for driving a crystal output (i.e., XTAL_OUT) terminal 105, and further includes a receiver circuit 110 responsive to a crystal input (i.e., XTAL_IN) terminal 109. External to the controller circuit 102, a crystal 112 is connected between the XTAL_OUT terminal 105 and the XTAL_IN terminal 109. Such a crystal 112 may be incorporated within the package of the controller circuit 102, or may be located on a printed wiring board (PWB) adjacent to the controller circuit 102. One terminal 106 of the crystal 112 is connected to the XTAL_OUT terminal 105, and the other terminal 108 of the crystal 112 is connected to the XTAL_IN terminal 109.
Within the controller circuit 102, an inverting gain element 114 is provided to close the loop incorporating the crystal 112 and sustain oscillation of the circuit. The inverting gain element 114 may be, in some embodiments, as simple as a digital inverter whose input and output terminals are biased nominally at a mid-rail voltage, such as by a resistor (not shown) coupling the input of the inverter 114 to the output of the inverter 114. Of note, the signal level generated on the XTAL_OUT terminal 105 by the driver 104 is typically a low-amplitude signal, as it needs merely to excite the crystal to resonate. Also provided within the controller circuit 102 is additional buffering, such as is represented by buffer 116, to amplify the output of receiver 110 and generate an internal clock signal on node 118 with a drive strength appropriate for the internal load within the controller circuit 102. If the controller circuit 102 desires to disable the oscillator circuit, such as for a low power mode of operation, the driver circuit 104 may be disabled, thus breaking the feedback loop and preventing oscillations on XTAL_IN node 109.
An oscillator circuit (i.e., sometimes described as a "stand-alone" oscillator circuit) is typically an active, 4-pin component that requires connection to power and ground, and has a digital enable input, and a digital clock output. Referring now to FIG. 2, a clock generator 150 is depicted utilizing a traditional oscillator circuit 162. A controller circuit 152 includes a driver circuit 154 for driving a digital clock enable output signal (i.e., CLKEN) onto output terminal 156, and further includes a receiver circuit 160 responsive to a digital clock input signal (i.e., CLK_IN) conveyed on input terminal 158. External to the controller circuit 152, an oscillator circuit 162 is coupled to a power supply voltage VDD conveyed on node 164, and further coupled to ground reference voltage (i.e., GND) conveyed on node 166. Both the VDD and GND connections are usually provided directly by a printed wiring board upon which the oscillator circuit 162 is typically mounted. The oscillator circuit 162 has an enable input EN connected to node 156 to receive the CLKEN signal from the controller circuit 152, and further has a clock output CLK_OUT connected to node 158 to provide the clock signal to the controller circuit 152.
Within the controller circuit 152, the receiver circuit 160 is included to generate an internal clock signal on node 118 with drive strength appropriate for the internal load within the controller circuit 152. The receiver circuit 160 may include multiple stages of buffering, as dictated by considerations within the controller circuit 152. Of note, the signal level generated on the CLKEN output terminal 156 is typically a full-rail digital signal, as is typical for digital control signals. If the controller circuit 152 desires to disable the oscillator circuit 162, such as for a low power mode of operation, the driver circuit 154 is driven to generate an inactive level on the CLKEN signal (i.e., to de-assert the enable signal), which disables the generation of the CLK_OUT signal by the oscillator 162 and may also put the oscillator into a low power state.

This patent is subject to a terminal disclaimer.

Oscillator circuit with transition detection enable


The invention provides a non-volatile semiconductor storage apparatus wherein silicon pillars are formed by epitaxial growth thereby to suppress a dispersion in channel length and improve the quality of a gate oxide film. In production, epitaxial silicon pillars are formed by selective epitaxial growth on a p-type silicon substrate, and a gate oxide film is formed over the overall area. Polycrystalline silicon is deposited and etched back to form a first polycrystalline silicon film serving as floating gates. Ion implantation is performed to form drain regions at the tops of the epitaxial silicon pillars and form a source region on the surface of the silicon substrate. A layered insulation film is formed, and polycrystalline silicon is deposited and etched back to form a second polycrystalline silicon film which covers over the side faces of the floating gates and serves as control gates. Bit lines are formed on the drain regions.

1. Field of the Invention
This invention relates to a non-volatile semiconductor storage apparatus and a process of producing the same, and more particularly to an electrically erasable non-volatile semiconductor storage apparatus which has a three-dimensional structure and a process of producing the same.
2. Description of the Related Art
In recent years, as an increase in storage capacity and degree of integration of semiconductor storage apparatus proceeds, attention is paid to a non-volatile semiconductor storage apparatus having a memory cell of a three-dimensional structure as a semiconductor storage apparatus in which cell arrays can be arranged with a high density. An exemplary one of such non-volatile semiconductor storage apparatus is disclosed in "Performance of the 3-D Sidewall Flash EPROM Cell", IEEE IEDM 93.2.1, 1993.
The structure and a process of production of an EEPROM flash memory are described below with reference to FIGS. 8 and 9. FIG. 8 is a plan view of the conventional three-dimensional EEPROM flash memory, and FIG. 9 is a sectional view taken along line 9'-9" in FIG. 8. As seen from FIGS. 8 and 9, a plurality of p-type silicon pillars 12 formed by etching are arranged in a matrix on a silicon substrate 1. A polycrystalline silicon film 5 serving as a floating gate is formed around each of the silicon pillars 12 with a gate oxide film 4 interposed therebetween.
A drain region 6 is formed at the top of each of the silicon pillars 12, and a source region 7 is formed continuously on the surface of the silicon substrate 1 around the individual silicon pillars 12. A second polycrystalline silicon film 9 serving as a control gate is formed around each of the polycrystalline silicon films 5 serving as floating gates with a layered insulation film 8 interposed therebetween. The second polycrystalline silicon films 9 are formed continuously in the direction of a row to construct word lines. The surfaces of the second polycrystalline silicon films 9 are covered with an interlayer insulation film 10. The drain regions 6 formed on the silicon pillars 12 are connected commonly for the individual columns to bit lines 11 which extend in the direction of a column.
The EEPROM is formed in the following manner.
1 An etching mask of a silicon oxide film is formed on a p-type silicon substrate 1, and the silicon substrate 1 is etched by RIE (Reactive Ion Etching) to form silicon pillars 12.
2 A gate oxide film 4 is formed by thermal oxidation, and deposition and etching back of polycrystalline silicon are performed to form a polycrystalline silicon film 5 on the side faces of each of the silicon pillars 12.
3 Ion implantation of arsenic is performed to form drain regions 6 and a source region 7.
4 A layered insulation film 8 is formed over the entire area, and deposition and etching back of polycrystalline silicon are performed to form second polycrystalline silicon films 9 which cover over the circumferences of the floating gates and fill up the gaps between the silicon pillars 12 in the direction of a row.
5 An interlayer insulation film 10 is formed.
6 The interlayer insulation film 10 on the silicon pillars 12 is removed, and deposition and patterning of a metal film are performed to form bit lines 11. By the process, a three-dimensional EEPROM flash memory is produced.
With the conventional process of production described above, since silicon pillars are formed by etching of a substrate, it is difficult to form the silicon pillars with an equal height. While the height is an important parameter which determines the channel length of a memory cell transistor, since silicon pillars of memory cell transistors produced by the conventional process exhibit a dispersion in height, they exhibit a large dispersion in threshold value V.sub.T upon erasure and writing of data, resulting in a drawback that the memory cell exhibits a high degree of possibility in malfunction (error in read-out).
Further, in the memory cell described above, upon erasure of data, a high voltage is applied to the source region 7 to remove electrons from the floating gates (polycrystalline silicon film 5). In this instance, the gate oxide film 4 is used as a tunnel oxide film. Since the gate oxide film is obtained by thermal oxidation of the silicon substrate 1 which has been damaged by etching performed for the formation of the silicon pillars, the gate oxide film reflects some of defects of the silicon substrate 1 and cannot be formed as a film of a high quality. Consequently, there is a problem in that the memory cell is Inferior in write repeat characteristics and erasure characteristics.
Also in a non-volatile semiconductor storage apparatus and a process of production of the same disclosed in Japanese Patent Laid-Open Application No. Heisei 6-112503, upon formation of a tunnel oxide film, a groove is formed on a silicon substrate by etching, and a floating gate, an interlayer insulation film, a control gate and so forth are formed in the groove. In this instance, since the tunnel oxide film is formed by thermal oxidation of the bottom and the side walls of the groove of the silicon substrate which has been damaged by the preceding etching, there is a problem in that the tunnel oxide film has a degraded film quality, which deteriorates the reliability of the memory cell.

Non-volatile semiconductor storage apparatus and production thereof


Disclosed embodiments include a method for reducing amplifier offset drift comprised of receiving a first differential input signal at a first transistor base terminal and a second differential input signal at a second transistor base terminal, coupling the collector of the first transistor to the emitter of a third transistor and the emitter of the second transistor to the emitter of a fourth transistor, then coupling the base of the third transistor to the base of the fourth transistor. The method is also comprised of coupling the collector of the fourth transistor to an output terminal, generating a temperature dependent error correction current to minimize the difference in the amount of current flowing through the third transistor and the amount of current flowing through the fourth transistor, then injecting the error correction current into the emitter terminal of at least one of either the third transistor or the fourth transistor.

If both inputs of an operational amplifier (op amp) are at exactly the same voltage, the op amp output would ideally be zero volts. In practice, however, a non-zero output is expected due to small component differences in the input paths of a non-ideal op amp. The offset voltage of an op amp is equal to the direct current (DC) voltage that must be applied between the two inputs of the op amp to obtain a zero volt output.
If the offset voltage was a constant value over different temperatures and operating conditions, it would be relatively simple to compensate for that offset voltage using well-known calibration and/or trim methods. However, the offset voltage is not constant over varying ambient operating temperatures. The change in offset voltage due to changes in operating temperature is known as temperature offset drift.
Some op amp manufacturers have tried to compensate for offset voltages, and the error caused by the offset voltages, by calibrating/trimming the op amp at room temperature. However, that offset calibration/trim may only be effective at the temperature the calibration/trim was performed. This temperature offset drift leads to increasing error in the amplifier output as the temperature changes and gets farther from the temperature at which the calibration was performed.

Compact offset drift trim implementation


Systems and methods are provided for autonomous airborne vehicle control using a millimeter-wave (MMW) radar. Embodiments of the present disclosure enable a MMW radar system to support an unmanned aerial vehicle (UAV) in accomplishing missions involving interacting with peers. In an embodiment, a MMW radar module of a UAV in accordance with an embodiment of the present disclosure enables the UAV to take a measurement (e.g., regarding the location of another UAV) using the MMW radar, classify a return (e.g., a MMW radar return), determine whether the detected object is a peer, and update the vehicle velocity accordingly.

Current small-size, low-cost unmanned air vehicles (UAVs) rely primarily on ground-based control and guidance. Onboard sensors are limited, leaving important capability gaps in military-relevant functions, such as terminal guidance, sense-and-avoid, swarming, and formation control. Operations at night or in degraded visual environments are heavily constrained. There is a need for sensor technology for small UAVs that overcomes the challenges of conventional UAV sensors.
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.

Autonomous airborne vehicle controlled by millimeter wave radar

The Government of the United States of America, as represented by the Secretary of the Navy


A method and apparatus are described for controlling demand of a fluid. The method includes measuring a fluid supply pressure in a supply pipe, determining that the fluid supply pressure is lower than a predetermined threshold supply pressure, and directing a control signal from the fluid information unit to the one or more demand control units to reduce demand for the fluid. In addition, a method and apparatus are described for measuring density of a fluid flowing through a demand pipe. The method includes determining that fluid flow through the demand pipe is stable, measuring fluid flow rate through the demand pipe, preventing the fluid from flowing into the demand pipe for a sample period of time, measuring a drop in fluid pressure in the demand pipe during the sample period, and determining the density from the measured pressure drop. Also, a utility meter for metering a fluid flowing through a supply pipe and a demand pipe having an audible indicator to provide an audible signal to a user is described.

A wide variety of fluid flow measuring devices have been developed for use in fluid delivery systems in an attempt to accurately determine the volume of the fluid delivered through the delivery system and, more particularly, to the volume of fluid delivered to a particular user of the fluid delivery system. Most natural gas utilities, for example, provide a gas meter at each user location. Such conventional gas meters typically include a diaphragm-type flow sensing apparatus having an accuracy that varies widely as the function of the relative pressure drop across the diaphragm and a number of environmental conditions, such as ambient temperature and relative atmospheric pressure. Such conventional gas meters are typically expensive, bulky, and very difficult to repair and maintain. Moreover, conventional gas and water utility meters require periodic manual reading of the meter in order to determine consumer usage of the fluid over a particular period of time. The manually collected fluid meter information must then be input to a computerized billing system which subsequently issues a bill to the consuming user on a periodic basis.
There is a trend in gas and water utilities towards increased competition for consumer business. Multi-tiered pricing schemes, for example, are currently being used by some utilities to charge users varying rates for gas and water depending on a particular usage. In accordance with such a pricing scheme, essential uses of natural gas, such as for air and water heating, for example, are generally priced at a lower rate than gas used for luxury purposes, such as for heating outdoor pools. Further, it is anticipated that enhanced control over gas and water delivery systems from remote locations will be desirable for providing enhanced service and safety features. It can be appreciated that conventional fluid metering devices and systems cannot be practicably adapted to provide such enhanced functionality, which will certainly be required in a de-regulated competitive utility market.


A method of co-producing vinyl acetate and ethyl acetate includes: (a) reacting ethylene, acetic acid and oxygen to form vinyl acetate and at least a minor amount of ethyl acetate; (b) providing a crude product stream containing the vinyl acetate and ethyl acetate of step (a) and acetic acid to a distillation tower; (c) separating the crude product stream into: (i) a vinyl acetate product stream enriched in vinyl acetate with respect to the crude product stream; (ii) an acid recycle stream enriched in acetic acid with respect to the crude product stream; (iii) a mixed sidestream containing vinyl acetate and ethyl acetate, the mixed sidestream being enriched in ethyl acetate with respect to the vinyl acetate product stream; and (d) hydrogenating vinyl acetate in the mixed sidestream to provide an ethyl acetate product stream.

The production of vinyl acetate is well known. The preferred method is by way of reacting of acetic acid (I) and ethylene (II) in the presence of oxygen to produce the vinyl acetic monomer (III):
Water and by-products are also produced, notably ethyl acetate. U.S. Pat. No. 6,420,595, entitled "Process Control for Vinyl Acetate Manufacturing" of Hallinan et al., provides an overview of the commercially preferred vapor-phase oxidation process wherein the crude product is fed to an azeotrope column and separated into a product stream and a waste ethyl acetate stream. Further details of this process appear in other patents, such as U.S. Pat. No. 6,410,817 to Colling and U.S. Pat. No. 6,696,596 to Herzog et al.
Alternatively, a liquid phase or mixed phase process can be used as is seen in U.S. Pat. No. 6,620,965 to Adams et al.
U.S. Pat. No. 5,225,388, entitled "Method for Making a Catalyst" of Wunder et al., relates to a process for the preparation of vinyl acetate from ethylene, acetic acid and oxygen or oxygen-containing gases on a catalyst which contains palladium and/or its compounds and, if desired, gold and/or gold compounds and alkali metal compounds as activators and, if desired, additionally cadmium compounds on a support which is composed of SiO2 or a SiO2—Al2O3 mixture having a surface area of 50-250 m2/g, a pore volume of 0.4-1.2 ml/g and a particle size of 4 to 9 mm, which comprises compressing the support particles with the aid of an Li, Mg, Al, Zn or Mn salt of a C2-C20 carboxylic acid or a mixture of such salts as binder.
U.S. Pat. No. 4,897,161, entitled "Separation of Vinyl Acetate from Ethyl Acetate by Extractive Distillation" of Berg et al., describes a process whereby vinyl acetate can be readily separated from ethyl acetate by means of extractive distillation using certain glycols or glycol ethers. Typical effective agents are 2-methyl-2,4-pentanediol, 1,3-butanediol, ethylene glycol methyl ether and diethylene glycol ethyl ether.
U.S. Pat. No. 4,818,347, entitled "Process for the Isolation of Vinyl Acetate" of Roscher et al., relates to a process for the isolation of vinyl acetate from a gas mixture containing vinyl acetate, ethyl acetate, water and carbon dioxide formed in the reaction of ethylene with acetic acid and oxygen in the gas phase over catalysts containing palladium or palladium compounds. The gas mixture leaving the reaction zone is passed into a distillation column and the gas mixture leaving the top thereof is cooled. The gas, which is not condensed during the cooling, is washed with acetic acid in a washing column, an acetic acid solution containing vinyl acetate being obtained. The bottom product from the distillation column is passed to a second distillation column and a side stream containing ethyl acetate is removed from an enrichment zone above the bottom thereof, all or some of the bottom product from the second distillation column, which product chiefly consists of acetic acid, being used for the wash in the washing column. The top vapor of the second distillation column is cooled. A portion of the organic phase of the condensate thereby formed is passed, together with the acetic acid solution obtained as the bottom product in the washing column, into a third distillation column, which may have an intermediate tray. The bottom product of the third distillation column is passed into a fourth distillation column. Pure vinyl acetate is removed at the top of the fourth distillation column.
Another process for the isolation of vinyl acetate by distillation is described in U.S. Pat. No. 5,066,365 entitled "Process for the Isolation of Vinyl Acetate by Distillation" of Roscher et al. This process for the isolation of vinyl acetate involves not combining the bottom product of the recycled gas washings with the water-saturated vinyl acetate but rather introducing it to further multiple distillation columns from the gas mixture formed in the reaction of ethylene with acetic acid and oxygen over catalysts containing palladium or palladium compounds in the gas phase.
A more exotic process is seen in U.S. Pat. No. 5,821,384, entitled "Process for Generating Vinyl Carboxylate Esters" of Zoeller et al., which describes a process for producing a vinyl carboxylate ester from a carbonyl compound and a carboxylic acid anhydride. The process comprises feeding a carboxylic acid anhydride to the middle portion of a reactive distillation column (RDC) while feeding a carbonyl compound to the lower section of the RDC and removing a product comprising the vinyl carboxylate ester. A carboxylic acid co-product corresponding to the anhydride reactant may be removed from the upper section of the RDC with the vinyl carboxylate ester, or from the upper section of the RDC as a separate side draw. Unreacted carbonyl may be removed from the RDC from the top along with the vinyl carboxylate ester or separately removed and recycled to the bottom portion of the RDC. Unreacted anhydride and an alkylidene dicarboxylate may be removed from the base of the RDC and recycled to the middle portion of the RDC. The product vinyl carboxylate may be further purified in one or two additional distillation vessels.
Ethyl acetate may be prepared by a variety of processes, including by way of direct addition of acetic acid with ethylene, or by way of oxidative acetoxylation of ethylene followed by hydrogenation of vinyl acetate or by way of esterification of acetic acid with ethanol. The process of preparing ethyl acetate by direct addition is relatively expensive because of the equipment required for the process. These processes are represented as follows:
Direct (Michael) Addition:
Oxidative Acetoxylation/Hydrogenation:
Esterification:

Other processes include those which use acetaldehyde or ethanol as starting materials.
The synthesis of lower aliphatic esters using heterpolyacids with an aldehyde-free product stream is described in U.S. Pat. No. 6,187,949 entitled "Synthesis of Lower Aliphatic Esters Using Heterpolyacids with an Aldehyde-Free Product Stream" of Froom et al. This invention describes a process for the production of lower aliphatic esters by bringing together in an addition reaction a lower olefin and a saturated, lower aliphatic, mono-carboxylic acid in the vapor phase into contact with a heterpolyacid catalyst. The reactant olefin and acids and any recycled feeds are rendered substantially free of aldehyde impurities prior to being brought into contact with the heterpolyacid catalyst. Acetaldehyde is a catalyst poison and removal of these from the feeds prolongs life and activity of the heteropolyacid catalyst.
U.S. Pat. No. 6,727,380 entitled "Oxidation Process for the Production of Alkenes and Carboxylic Acids" of Ellis et al., U.S. Pat. No. 6,548,697 entitled "Oxidation Process for the Production of Alkenes and Carboxylic Acids" of Ellis et al., and U.S. Pat. No. 6,476,261 entitled "Oxidation Process for the Production of Alkenes and Carboxylic Acids" of Ellis et al., describe a process for the oxidation of a C2 to C4 alkane to produce the corresponding alkene and carboxylic acid and further to integrated processes in which a portion of the produced alkene and carboxylic acid are used as reactants, in a second reaction zone, for the production of alkyl carboxylates.
U.S. Pat. No. 5,936,117, entitled "Carbonylation of Olefins" of Zoeller et al., describes a process for the preparation of aliphatic carbonyl compounds selected from aliphatic carboxylic acids, alkyl esters of aliphatic carboxylic acids and anhydrides of aliphatic carboxylic acids by the carbonylation of olefins in the presence of a catalyst system comprising (1) a primary component selected from at least one Group 6 metal, i.e., chromium, molybdenum, and/or tungsten and (2) a secondary component selected from at least one of certain halides and tertiary and quaternary compounds of a Group 15 element, i.e., nitrogen, phosphorus and/or arsenic. The process can be carried out at moderate carbonylation conditions without the necessity of using an expensive noble metal catalyst, volatile, toxic materials such as nickel tetracarbonyl, formic acid or a formate ester. U.S. Pat. No. 4,405,808 entitled "Process for Preparing Acetic Acid Esters" of Nakajima et al. describes a process for preparing acetic acid esters by reacting acetic acid with an aliphatic lower olefin in vapor phase in the presence of steam and a catalyst selected from aromatic disulfonic acids and their esters. The high activity of the catalyst can be maintained and the product is obtained in a high space time yield by the presence of steam in the reaction. The effect of maintaining the high activity can be further increased by using silica treated with a strong acid as a carrier.
U.S. Pat. No. 4,365,084, entitled "Preparation of Alkyl Carboxylates" of Young, describes a method for the preparation of alkyl carboxylate compounds, and especially α-methylalkyl carboxylate compounds, by reaction of an olefin and a carboxylic acid compound in the presence of a particular type of zeolite catalyst. The zeolites are characterized by a silica to alumina mole ratio of at least 12 and a constraint index of 1 to 12.
In connection with the production of either vinyl acetate or ethyl acetate a large portion of the capital and operating expense is due to purification requirements as is appreciated from the above references, as well as those discussed below.
WO 03/011809 to BP Chemicals, Feb. 2, 2003, describes a process for separating secondary butanol impurity from ethyl acetate by feeding the impure ethyl acetate to a distillation column operating at a pressure of less than 1 bar absolute. This provides (1) a stream comprising ethyl acetate as a major component and (2) a residue or a second stream comprising at least some secondary butanol from ethyl acetate. The process can be applied to purifying ethyl acetate derived from (a) catalytic reaction of ethylene with acetic acid followed by (b) a hydrogenation step. The 2-butanone impurity produced in step (a) is difficult to separate from ethyl acetate, and step (b) converts it to secondary butanol, which can be separated by reduced pressure fractionation.
A process for removing at least one compound selected from acetic acid, acetate esters and aldehydes from a gaseous fraction additionally containing carbon dioxide is described in U.S. Pat. No. 6,663,692 entitled "Process for Purifying Carbon Dioxide-Containing Gas Streams" of de Poitiers et al. The process includes the steps of scrubbing in a scrubber at least part of the gaseous fraction with water and acetic acid to remove the acetic acid, acetate esters and/or aldehydes and removing carbon dioxide from the scrubbed product by absorption in aqueous potassium carbonate. The process may be used to remove acetate esters such as vinyl acetate and ethyl acetate and aldehydes such as acetaldehyde. The process may be employed in the manufacture of vinyl acetate by the reaction of ethylene, acetic acid and an oxygen-containing gas in the presence of a catalyst, or in the catalytic oxidation of (a) ethane and/or (b) ethylene to produce respectively (a) acetic acid and/or ethylene and (b) acetic acid.

Co-production of vinyl acetate and ethyl acetate


A method which enhances a disinfection process by using a catalyst which increases in effective surface area during the process. Also disclosed are contact lens disinfecting systems which are designed to maintain a high concentration of hydrogen peroxide solution for a longer period of time before increasing the overall surface area of catalyst exposed to the hydrogen peroxide solution. The devices utilize pressure from expanding oxygen generated within the system through use of a small catalyst, or through exposure of only a small portion of a large catalyst, to control deployment of the large catalyst for completing disproportionation of the hydrogen peroxide.

The present invention generally relates to methods and apparatus for controlling the decomposition of a solution using a catalyzing agent, and more specifically relates to a method and apparatus for controlling and enhancing a disinfection process.
The present invention relates to an improved disinfection method and apparatus which utilizes, for example, hydrogen peroxide solution and a catalyzing agent to facilitate controlled decomposition of the hydrogen peroxide within a sealed reaction chamber containing an object to be disinfected, such as contact lenses, wherein the solution, the decomposition catalyzing agent, the resulting energy, and byproducts of decomposition are employed to control and enhance the disinfection process.
While the method disclosed herein may be utilized, for example, to disinfect contact lenses, particularly soft contact lenses, the method may also be suitable to disinfect other types of items, for example larger items, such as non-sterile medical or dental appliances and the like, within a reaction chamber appropriately scaled to size. As such, while the present disclosure focuses on using the method (and associated apparatus) to disinfect contact lenses using hydrogen peroxide, it should be understood that the method can be used in other disinfecting applications.
Hydrogen peroxide is unstable and eventually decomposes (disproportionates) into water and oxygen over time. The decomposition occurs more quickly if the hydrogen peroxide is, for example, subjected to temperature extremes, exposed to ultraviolet light, or introduced to a catalyzing agent. The decomposition rate is also affected by its percentage of concentration, its pH, and the presence of impurities and stabilizers. The decomposition process is exothermic in nature and when a catalyzing agent has been introduced to the hydrogen peroxide, evolved thermal energy and oxygen can accelerate the process by several means that increase molecular contact opportunities with the catalyzing agent. The means include creation of thermally inspired convection, mechanical mixing resulting from the stirring effect of rising oxygen bubbles, as well as increased molecular motion which lowers the energy threshold for decomposition.
Hydrogen peroxide is a larger molecule than water with a specific gravity of 1.443 and a viscosity of 1.245 cP at 20 degrees Celsius, compared to water which has a viscosity of 1.003 cP at 20 degrees Celsius. Nevertheless, each is entirely miscible with the other, allowing a limitless variety of concentration levels to be tailored to suit various applications. Hydrogen peroxide solutions formulated for disinfection may contain surfactants, and are often pH-modified and chemically-stabilized in order to assure reasonable shelf life and potency at the time of use. Hydrogen peroxide formulated for disinfection of contact lenses, for example, is generally supplied at a concentration of no less than 3.0%, and may range up to 4.0% in order to assure that a minimum concentration of 3.0% is available for disinfection.
While more highly concentrated solutions would be more potent and effective against pathogens, the use of more highly concentrated solutions has generally not been pursued for contact lens care use. This is due to the strong oxidizing nature of hydrogen peroxide, and the damaging effects such higher concentrations could have upon accidental, full strength contact with sensitive ocular tissue. Typically, peroxide for the purpose of disinfecting contact lenses is supplied at 3.7% concentration.
Catalysts that facilitate decomposition of hydrogen peroxide include most of the transition metals, manganese dioxide, silver and the enzyme catalase. Quite commonly in connection with single step contact lens disinfection systems, platinum is introduced to the solution in the form of a surface coating on a polymeric support structure. Catalysts function by changing the energy pathway for a chemical reaction. FIG. 1 provides a graph which compares the energy associated with activating without a catalyst (line 10) to the energy associated with activating with a catalyst (line 12). As indicated, when introduced to hydrogen peroxide, a catalyst serves to lower the activation energy required to initiate decomposition of the hydrogen peroxide under ambient conditions in which it was otherwise stable.
The combination of solution temperature, exothermally-generated heat, thermally-inspired convection, mechanical stirring from evolving oxygen bubbles, dilution resulting from disproportionation, dissolved gas in the solution, and changes in ambient pressure has been found to impact the rate at which the catalyzed reaction progresses. In an open environment such as that provided by a typical commercially-available hydrogen peroxide disinfection cup system for contact lenses, for example the AO SEPT system (as shown in FIG. 2, with the overall system being identified with reference numeral 13) offered by Ciba Vision, contact lenses are introduced to 10 milliliters of the hydrogen peroxide solution essentially simultaneously with the catalyst, and evolved oxygen from the reaction is subsequently vented off through a hydrophobic membrane or one way valve (indicated with reference numeral 14 in FIG. 2) in the cap (indicated with reference numeral 15 in FIG. 2). As shown in FIG. 3, with this type of system, solution concentration resulting from the catalyzed reaction declines rather rapidly to about 0.1%, whereupon six to eight hours are required before the concentration of the solution bath has been reduced to a level that is safe for a disinfected lens to be inserted in the eye without risk of ocular irritation to the user.
Disinfection of contact lenses is regularly practiced by lens wearers in order to eliminate a variety of environmentally ubiquitous organisms known to be found on contaminated lenses. The organisms at issue include, but are not limited to, various pathogenic strains of Staphylococcus, Pseudomonas, E. Coli, Acanthamoeba, and the like. Acanthamoeba is an opportunistic pathogen associated with a potentially blinding infection of the cornea termed Acanthamoeba keratitis. Among the general population, contact lens wearers are believed to be most at risk to this organism, accounting for more than 95% of reported cases of the ocular infection. A particularly insidious organism, Acanthamoeba can transition from active trophozoite to a dormant, more resistant encysted stage when exposed to conditions of starvation, desiccation, and changes in pH and temperature. Once encysted, this organism's resistance to biocides results largely from the physical barrier of its cyst walls rather than as a consequence of metabolic dormancy. The major components of the cyst's walls are acid-resistant proteins and cellulose, with the outer wall, or exocyst, composed primarily of protein and the inner endocyst comprised of over 30% cellulose. Although remarkably resistant to chlorine-hearing disinfectants and even hydrochloric acid, encysted Acanthamoeba is subject to destruction by exposure to hydrogen peroxide. Acanthamoeba cysts exhibit greater susceptibility to hydrogen peroxide as the disinfectant's concentration is increased. The impact of hydrogen peroxide's concentration upon Acanthamoeba cysts was documented in a study by Reanne Hughes, Peter W. Andrew and Simon Kilvington of the Department of Microbiology and Immunology, University of Leicester, Leicester, UK, published in the May 2003 edition of "Applied and Environmental Microbiology". A graph extracted from that study and shown in FIG. 4 illustrates the impact of 1%, 2% and 3% hydrogen peroxide solutions over a period of time upon killing the target Acanthamoeba cyst. In FIG. 4, line 20 relates to the 1% hydrogen peroxide solution, line 22 relates to the 2% hydrogen peroxide solution, and line 24 relates to the 3% hydrogen peroxide solution.
Under standard ambient conditions, the method by which hydrogen peroxide destroys pathogens is through oxidation resulting in denaturation of the organism's proteins. One option to deal with heavily contaminated lenses or resistant organisms, such as Acanthamoeba, would be to start with a more highly concentrated solution, but there are undesirable user risks associated with that approach. Some of these risks have already been discussed hereinabove.
A more attractive option would be to slow the decomposition process in order to maintain a higher concentration of hydrogen peroxide for a longer period of time before finally reducing the concentration to an ocularly comfortable level. With such an approach, more heavily contaminated lenses could therefore be disinfected, and resistant organisms could be better dealt with using solutions that have commonly-accepted concentrations. Unfortunately, present day disinfection systems are limited by the reaction rate necessary to obtain irritation-free disinfected lenses at the end of a reasonable 6 to 8 hour overnight wait period. This results from a balance that has historically been struck between the volume of peroxide solution, a safe and practical starting concentration level for the peroxide, and the size of catalyst (such as platinum) necessary to assure adequate decomposition in use. Regarding catalyst size, typically 94 square millimeters to 141 square millimeters of catalyst surface area is allocated for each milliliter of 3.0% to 4.0% hydrogen peroxide solution. Although an undersized catalyst would certainly slow the decomposition process, keeping concentrations higher for a longer period of time, using an undersized catalyst may result in the lens solution not reaching user comfort levels within a reasonable time period, since the significance of catalyst surface area actually increases as the amount of released energy and solution concentration declines. Additionally, methods (such as is disclosed in U.S. Pat. No. 5,468,448) of slowing decomposition by using buoyant catalysts that have contact areas which increase as they sink from loss of attached bubbles have proven too difficult to commercialize reliably.

Method and devices for improved disinfection process


The effluent monitoring system generates an action perform signal for controlling a sampler device or an alarm in response to detecting a plurality of probe inputs receiving signals from a plurality of effluent property detecting probes. A variable and dynamic response to the probe inputs is provided. A plurality of monitoring parameter sets are stored in a memory along with a state number value, and the system may change state number in response to exceeding a threshold value which will result in the system being responsive to a new set of monitoring parameters in order to respond in a variable and dynamic manner. The sampling rate and the rate of recording values of the probe inputs can also be dynamically varied in response to the probe inputs themselves.

Traditionally, waste water quality monitoring was provided by lowering bottles, attached to a rope in the sewer to take samples. A few years ago, automatic samplers came on the market, driven by clocks and/or an external trigger. Today's machines, although often micro-computer driven, reflect their origins and are able to perform only very simple tasks. Typically they have probes that measure pH and temperature (parameters that appear in most by-laws on sewage), sometimes dissolved oxygen and conductivity; the output of these probes is either, via analog comparators, continuously compared to some preset threshold, or sampled through digital techniques for comparison with the digital equivalent of the mentioned thresholds.
To summarize the actual state of the art, water quality monitors can perform the following tasks:
Take a sample at a fixed interval by controlling a mechanical sampler; PA1 Read and sometimes record the values of one or more probes at a fixed interval; PA1 Take a sample when controlled by an external trigger (e.g. flow meter); and PA1 Take a sample and/or record the value when one or more of the measured parameters exceed some threshold. PA1 From 1 min. to 59 h 59 min. in 1 min. increments between consecutive samples; PA1 Non-uniform times in minutes or clock time; PA1 Random time interval between consecutive samples; PA1 From 1 to 9,999 flow pulses in single-pulse interval; and PA1 Flow paced in volume with attachable flow module.
A typical embodiment of a state of the art system is the ISCO (T.M.) family of samplers and flow meters. In the 6700 model, for example, the sample frequency can be selected as:
Optionally, one can add a pH module that can trigger samples when pH is outside a user provided range.
These systems are not well suited for long time base monitoring because, either they generate large amounts of monotonous data, or can ignore short term significant phenomena. Besides, the fixed threshold system can fill the sampler very fast, so that no bottles are available to receive interesting samples later on.


A chemical mechanical polishing slurry comprising an oxidizing agent, a fluoride containing additive and an abrasive and a method for using the fluoride containing additive chemical mechanical polishing slurry to remove tungsten and titanium from substrates.

(1) Field of the Invention
The present invention relates to a chemical mechanical polishing slurry including a fluoride containing additive. This invention is also related to methods for using the chemical mechanical polishing slurry to polish multiple metal layers and thin-films in a single step during the manufacture of integrated circuits and semiconductors.
(2) Description of the Related Art
Integrated circuits are made up of millions of active devices formed in or on a silicon substrate. The active devices, which are initially isolated from one another, are united to form functional circuits and components. The devices are interconnected through the use of well-known multilevel interconnections.
Interconnection structures normally have a first layer of metallization, an interconnection layer, a second level of metallization, and sometimes a third and subsequent level of metallization. Interlevel dielectrics such as doped and undoped silicon dioxide (SiO.sub.2), are used to electrically isolate the different levels of metallization in a silicon substrate or well. The electrical connections between different interconnection levels are made through the use of metallized vias. U.S. Pat. No. 4,789,648, which is incorporated herein by reference, describes a method for preparing multiple metallized layer and metallized vias in insulator films. In a similar manner, metal contacts are used to form electrical connections between interconnection levels and devices formed in a well. The metal vias and contacts are generally filled with tungsten and generally employ an adhesion layer such as titanium nitride (TiN) and/or titanium to adhere a metal layer such as a tungsten metal layer to SiO.sub.2. At the contact level, the adhesion layer acts as a diffusion barrier to prevent tungsten and SiO.sub.2 from reacting.
In one semiconductor manufacturing process, metallized vias or contacts are formed by a blanket tungsten deposition followed by a chemical mechanical polish (CMP) step. In a typical process, via holes are etched through an interlevel dielectric (ILD) to interconnection lines or to a semiconductor substrate. Next, a thin adhesion layer such as titanium nitride and/or titanium is generally formed over the ILD and is directed into the etched via hole. Then, a tungsten film is blanket deposited over the adhesion layer and into the via. The deposition is continued until the via hole is filled with tungsten. Finally, the excess metal is removed by chemical mechanical polishing, (CMP) to form metal vias. Processes for manufacturing and/or CMP of ILD's are disclosed in U.S. Pat. Nos. 4,671,851, 4,910,155 and 4,944,836.
In a typical chemical mechanical polishing process, the substrate is placed in direct contact with a rotating polishing pad. A carrier applies pressure against the backside of the substrate. During the polishing process, the pad and table are rotated while a downward force is maintained against the substrate back. An abrasive and chemically reactive solution, commonly referred to as a "slurry" is deposited onto the pad during polishing. The slurry initiates the polishing process by chemically reacting with the film being polished. The polishing process is facilitated by the rotational movement of the pad relative to the substrate as slurry is provided to the wafer/pad interface. Polishing is continued in this manner until the desired film on the insulator is removed.
The slurry composition is an important factor in the CMP step. Depending on the choice of the oxidizing agent, the abrasive, and other useful additives, the polishing slurry can be tailored to provide effective polishing to metal layers at desired polishing rates while minimizing surface imperfections, defects and corrosion and erosion. Furthermore, the polishing slurry may be used to provide controlled polishing selectivities to other thin-film materials used in current integrated circuit technology such as titanium, titanium nitride and the like.
Typically CMP polishing slurries contain an abrasive material, such as silica or alumina, suspended in an oxidizing, aqueous medium. For example, U.S. Pat. No. 5,244,523 to Yu et al. reports a slurry containing alumina, hydrogen peroxide, and either potassium or ammonium hydroxide that is useful to remove tungsten at predictable rates with little removal of the underlying insulating layer. U.S. Pat. No. 5,209,816 to Yu et al. discloses a slurry comprising perchloric acid, hydrogen peroxide and a solid abrasive material in an aqueous medium. U.S. Pat. No. 5,340,370 to Cadien and Feller discloses a tungsten polishing slurry comprising approximately 0.1M potassium ferricyanide, approximately 5 weight percent silica and potassium acetate. Acetic acid is added to buffer the pH at approximately 3.5.
U.S. Pat. No. 5,340,370 discloses two slurries. The first slurry is useful for polishing tungsten and includes an abrasive and an oxidizing agent such as potassium ferricyanide. The second slurry is useful for polishing titanium and includes a fluoride salt complexing agent and an abrasive. The reference further discloses that detrimental polishing results are obtained when the slurries are combined.
It has been recognized that CMP slurries have low polishing rates towards titanium. As a result, the polishing step is lengthened or operated at aggressive polishing conditions that can cause undesirable erosion of the SiO.sub.2 layer and recessing of the tungsten vias. Such recessing causes a non-planar via layer to be formed which impairs the ability to print high resolution lines during subsequent photolithography steps and can cause the formation of voids or open circuits in the metal interconnections formed above. Additionally, recessing increases when over polishing is used to ensure complete removal of the titanium and tungsten films across the surface of a wafer. Thus, presently available CMP slurries are inadequate to reliably polish a plurality of metal layers including a titanium layer in an integrated circuit. Accordingly, a new CMP polishing slurry that polishes titanium at a higher rate is needed to overcome the present substrate manufacturing reliability issues.

Fluoride additive containing chemical mechanical polishing slurry and method for use of same


A sputtering target for magnetic recording media capable of producing a magnetic thin film in which the magnetic crystal grains are micronized and the distance between the centers of the grains is reduced while good magnetic properties are maintained. The target including metallic Pt and an oxide, with the balance being metallic Co and inevitable impurities, wherein the Co is contained in a range of 70 at % to 90 at % and the Pt is contained in a range of 10 at % to 30 at % relative to a total of metallic components in the sputtering target for magnetic recording media, the oxide is contained in a range of 26 vol % to 40 vol % relative to a total volume of the sputtering target for magnetic recording media, and the oxide is composed of B2O3 and one or more high-melting-point oxides having a melting point of 1470° C. or higher and 2800° C. or lower.

In a magnetic disk for a hard disk drive, information signals are recorded in fine bits of a magnetic recording medium. In order to further improve the recording density of the magnetic recording medium, it is necessary to increase the ratio of signal to noise, which is an index of the information quality, while reducing the size of the bit holding one piece of recording information. In order to increase the ratio of signal to noise, it is essential to increase the signal or reduce the noise.
At present, a magnetic thin film having a granular structure of a CoPt-based alloy-oxide is utilized as a magnetic recording medium that serve to record information signals (see, for example, Non-Patent Literature 1). The granular structure is composed of columnar CoPt-based alloy crystal grains and crystal grain boundaries formed from an oxide that surrounds the columnar CoPt-based alloy crystal grains.
When the recording density of such a magnetic recording medium is increased, it is necessary to smoothen transitional regions between recording bits to reduce noise. In order to smoothen the transitional regions between the recording bits, it is essential to micronize the CoPt-based alloy crystal grains contained in the magnetic thin film.
As the magnetic crystal grains become finer, the intensity of the recording signal that one magnetic crystal grain can hold becomes smaller. In order to achieve both the micronization of the magnetic crystal grains and the intensity of the recording signal, it is necessary to reduce the distance between the centers of the crystal grains.
On the other hand, the progress of micronization of the CoPt-based alloy crystal grains in a magnetic recording medium has sometimes resulted in occurrence of the so-called thermal fluctuation phenomenon, in which the superparamagnetic phenomenon impairs the thermal stability of recorded signals and leads to loss of the recorded signals. This thermal fluctuation phenomenon has contributed a major obstacle to increasing the recording density of magnetic disks.
In order to surmount this obstacle, the magnetic energy of respective CoPt-based alloy crystal grains needs to be increased such that the magnetic energy exceeds the thermal energy. The magnetic energy of respective CoPt-based alloy crystal grains is obtained by v×Ku, which is a product of the volume v of the CoPt-based alloy crystal grains and the magnetocrystalline anisotropy constant Ku. Therefore, the magnetocrystalline anisotropy constant Ku of the CoPt-based alloy crystal grains needs to be increased in order to increase the magnetic energy of the CoPt-based alloy crystal grains (see, for example, Non-Patent Literature 2).
In addition, in order to grow the CoPt-based alloy crystal grains having large Ku in a columnar shape, phase separation between the CoPt-based alloy crystal grains and grain boundary material must be achieved. If the phase separation between the CoPt-based alloy crystal grains and the grain boundary material is insufficient to increase the grain interaction between the CoPt-based alloy crystal grains, the magnetic thin film having the granular structure of the CoPt-based alloy-oxide has had reduced coercive force Hc. As a result, the thermal stability is impaired, and the thermal fluctuation phenomenon may occur with ease. Thus, it is important to reduce the grain interaction between the CoPt-based alloy crystal grains.
The micronization of the magnetic crystal grains and the reduction of the distance between the centers of the magnetic crystal grains may be achieved by micronizing the crystal grains in the Ru underlayer (underlayer provided for orientation control of the magnetic recording medium).
However, it is difficult to micronize crystal grains in the Ru underlayer while maintaining the crystal orientation (see, for example, Non-Patent Literature 3). Therefore, the size of the crystal grains in the Ru underlayer of the current magnetic recording medium is almost the same as that when the longitudinal magnetic recording media are switched to the perpendicular magnetic recording media, and is about 7 to 8 nm.
From the viewpoint of improving the magnetic recording layer instead of the Ru underlayer, an investigation has been made to advance the micronization of magnetic crystal grains. Specifically, an investigation was made to increase the addition amount of the oxide in the CoPt-based alloy-oxide magnetic thin film to decrease the volume ratio of the magnetic crystal grains to micronize the magnetic crystal grains (see, for example, Non-Patent Literature 4). This technique achieved the micronization of the magnetic crystal grains, but has not been able to reduce the distance between the centers of the magnetic crystal grains because the width of the crystal grain boundary increases due to an increase in the addition amount of the oxide.
In addition, an investigation was made to add a second oxide in addition to the single oxide used in the conventional CoPt-based alloy-oxide magnetic thin film (see, for example, Non-Patent Literature 5). However, when a plurality of oxide materials is added, there is no clear guideline for selecting the materials, and even today, the investigation for searching oxides used as grain boundary materials for the CoPt-based alloy crystal grains is being continued.

Sputtering target for magnetic recording media


Provided is a vehicle front structure including a front bumper and a lower grille. The front bumper includes a front-bumper lower surface extending in a vehicle rear direction, the front-bumper lower surface having a pair of bottom surface portions at respective side portions and a recessed surface at a center portion, the recessed surface extending from the pair of bottom surface portions and being recessed in an upper direction. The lower grille includes an annular portion arranged at the lower side of a rear end of the recessed surface and forming an opening, a protruding portion protruding from a lower portion of the annular portion so as to protrude in a front direction and oppose to the recessed surface, and a reinforcing portion extending from an upper portion of the annular portion to a back surface of the recessed surface and reinforcing the front-bumper lower surface.

In related art, there is a vehicle front structure including a lower grille for cooling a radiator etc. provided on the lower side of a front bumper as disclosed in Japanese Unexamined Patent Application Publication No. 2010-254116.
Also, Japanese Unexamined Patent Application Publication No. 2010-254116 discloses the collision energy absorbing structure in which the lower grille arranged on the lower side of the front bumper has a low rigidity to protect a pedestrian and absorbs collision energy if a pedestrian collides with the front bumper.
Meanwhile, a vehicle front structure in recent years includes a safety plate provided at a front bumper to protect a pedestrian. The safety plate sweeps the legs of the pedestrian. Accordingly, if the pedestrian collides with the front bumper, below knee portions of the pedestrian are swept and the pedestrian is lifted on a hood without buckling of the front bumper. Thus, the impact of the collision is reduced.
In the following description, sweeping the below knee portions of the pedestrian and lifting the pedestrian on the hood is called safety plate function.
However, with the vehicle front structure including the lower grille of related art, since the lower grille has the low rigidity, the lower grille cannot provide the safety plate function.
In contrast, if the safety plate is provided at the vehicle front structure including the lower grille of related art, the number of parts is increased, thereby disturbing demand for reduction in the number of parts. Also, the increase in the number of parts results in an increase in the number of mounting steps. This is not preferable.


To control the processing of a work item, the work item is stored in a database of work items and is executed by an operator. Organizations use the database, and the operator belongs to one of the organizations. Organization identifiers are associated with corresponding organizations, and definitional data items are associated with corresponding organization identifiers. The definitional data items define rules that can be altered after the system is initially configured and while the system is running.

The invention relates generally to computer executable workflow management and control systems and more particularly to computer system executable methods for controlling access to, or processing of, a work item in a database of workflow work items stored by the computer system.
As is known in the art, members of an organization having an organizational structure are provided work items for execution from a database of unexecuted work items. These work items represent tasks such as filling out documents, returning telephone calls to potential or existing customers, initiating transactions, or similar duties. Work items may arrive at the database from outside the organization or from inside the organization or both. For example, if the organization provides financial services, the work items may relate to client account maintenance, buy and sell orders, internal management directives, and the like.
Efficiency gains can be accomplished by implementing a workflow management system that automates a process for distributing the work items to the members of the organization (i.e., operators). The work items are stored in a database. Associated with the work items is definitional data. The definitional data includes a plurality of definitional data items. Each definitional data item includes, for example: information about steps (i.e., nodes) in a process for manipulating the work item; information about a characteristic of a list (i.e., a queue associated with a node) of work items appropriate for execution in connection with a node; information about a rule specifying a protocol for executing the work item, such as a display characteristic for the work item; or information about a characteristic of the operator, or operators, who may work on the work item. In general, a node typically represents a single task in a work environment; for example, the single task may be "submitting new account applications." More particularly, a node represents a unit step of work specified in one or more processes; for example, a process for handling new account applications may have a node representing a unit step being "new account application approval." Each node may be used in more than one process and may be associated with a department having responsibility for the single task or unit step of work.
In the workflow management system, each member of the organization (i.e., each operator) is situated at a computer station, such as a personal computer. The computer stations are connected to a computer system running a workflow application program. The operator requests a work item from the database. After a work item is assigned, processed, displayed in accordance with the definitional data, and then completed by the operator, a new work item is provided from the database to the computer station in response to another request from the computer station.
Some organizations are structured into separate sub-organizations such as departments or divisions or separate business units, with each such sub-organization requiring some control over access to and processing of the sub-organization's work items. For example, the sub-organizations may require different sets of rules governing the flow of work items but may also need to share work items. If the sub-organizations use separate databases to control access and processing, and maintain separate sets of rules, the work items may be shared by making and distributing copies of the work items. In such cases, it is necessary to keep track of the copies and also to ensure cross-database consistency of definitional data concerning the shared work items.
One proposed system allows a single database to be used to store the work items of different sub-organizations. In the proposed system, each sub-organization maintains general access rules unrelated to the specific type of business activity performed by the sub-organization. Further, with the proposed system the access rules maintained by each sub-organization are provided specifically to prevent access by the sub-organization to work items not pertaining to the sub-organization. A change in the structure of the organization or one of the sub-organizations typically requires changes to each sub-organization's access rules.

Computer executable workflow control system


The invention combines tiles with an optimal width to thickness ratio together into array(s), and then affixes the array(s) to a depressible adhesive coated substrate. This combination of array(s) and substrates compliments the optimal tile thickness to width ratio to create a more advantageous directional shift of energy dissipation that creates a yaw of the bullet's direction, and subsequent increase of ceramic thickness that the projectile must pass through. The invention eliminates hard epoxies and rigid fiber induced wraps to create a truly flexible matrix that can be applied for use to protect the body with traditional concealable or tactical carriers, or can be used as a “peel and stick” high threat armor system that can be easily field mounted to a vehicle, structure, or aircraft.

Early in the 1990's the evolution of scalar type armor was reinvented using 1″ diameter 0.032 thick titanium alloy discs in an imbricated pattern applied to an adhesive coated high strength fabric substrate(s). This eliminated rivets, wires, or sewn envelops as was the method of affixing tiles or coins in a scalar armor format using the prior art. Further evolution of this method involved using larger high toughness metallic or high hardness ceramic 2″ diameter disks formed into a discus shape to limit weight and thickness of the redundant overlaps inherent in scalar armor. The problem however with scalar rifle resistant armor systems has always been the excessive thickness and weight caused by the redundant two and three tile overlaps present over the entire system. These overlapped areas when flexed caused weak areas of the system, and a weight penalty that is no longer competitive in the current art of today's modern ballistic armor systems. Thus there is a need to reduce the weight and thickness while improving flexibility of an armor system meant to defeat rifle rounds in the modern era of armor meant for body protection, vehicles, aircraft, and structures.

Non-scalar flexible rifle defeating armor system


An embodiment may involve persistent storage containing definitions of a set of queues and a set of servers, and wherein the servers are respectively associated with deactivation times. One or more processors may be configured to: (i) identify, by an assignment engine, an incoming request in a particular queue, wherein the incoming request is ready for assignment to one of the servers; (ii) determine, by the assignment engine and based on data associated with the incoming request, an expected duration for servicing of the incoming request; (iii) calculate, by the assignment engine and based on the deactivation times, times remaining in service for each of the servers; (iv) select, by the assignment engine and from the servers, a particular server that has a time remaining that is greater than the expected duration; and (v) assign, by the assignment engine, the incoming request to the particular server.

Clusters of servers may be arranged to handle incoming requests from one or more queues. The assignment of requests to servers is a complex task and often one for which there is no computably optimal solution. Instead, a number of heuristics may be applied, such as using a first-in-first-out strategy for selecting queued requests and round-robin load balancing. While these techniques provide reasonable results in many situations, modern clustered server systems can be complex and exhibit additional constraints that should be considered.

Assignments of incoming requests to servers in computing clusters and other environments