An information flow control device has: a first network interface card on a transmission side, the first network interface card including first and second transceivers, each of the first and second transceivers having a transmit port and a receive port; and a second network interface card on a receiving side, the second network interface card including at least one receive port. A first data connection segment connects the first transceiver transmit port to the second transceiver receive port, a second data connection segment connects the second transceiver transmit port to the first transceiver receive port, and a third data connection segment connects the first transceiver transmit port to the receive port of the second network interface card. The first and second segments provide continuity, while the third segment provides one-way data transfer. The first and second transceivers are replaceable with third and fourth transceivers to provide different throughput.

The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, the approaches described in this section may not be prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
When information must be transferred between isolated networks of differing confidentiality or integrity, existing information security models (e.g., Bell-LaPadula and Biba) favor implementation of one-way information flow controls. Examples include: (i) ingest of business intelligence and military intelligence information into confidential networks where backward flow is considered breach of secrecy; and (ii) release of real-time state information from a high-integrity Industrial Control System (ICS) networks for purposes of remote monitoring where ingress of malicious software could disable operations. Examples of the latter include Industrial Control System (ICS) networks in nuclear power plants.
Information flow control may be implemented in software or hardware. However, software is known to be vulnerable to various forms of software attack, which makes hardware-enforced flow control more attractive because unauthorized reconfiguration of the security device cannot be achieved without physical access to the device.
For some high-impact sectors of the US designated as "critical infrastructure" and defined accordingly by the Department of Homeland Security, implementation of hardware-enforced, one-way information flow control devices to protect critical networks are now required by law. One example of "critical infrastructure" sector is the US nuclear industry.
The US National Institute of Standards and Technology (NIST) defines an explicit security control (information security risk mitigation method) in NIST's Special Publication (SP) 800-53, "Catalog of Security Controls for Federal Information Processing Systems," AC-4 (7). INFORMATION FLOW ENFORCEMENT|ONE-WAY FLOW MECHANISMS: "The information system enforces [Assignment: organization-defined one-way information flows] using hardware mechanisms."
Historically, one-way information flow control devices, also known as "data diodes," have been unreliable, slow, difficult to configure (and thus prone to user error), and/or very expensive, and few vendors offer one-way information flow control products. The majority of one-way information flow control products were implemented in software, typically by implementing network access restrictions in commercial firewalls from vendors such as Cisco™ and Sidewinder™. Some specialty one-way information flow control devices, e.g., those produced by Tresys™, implement software that is secured using SE Linux security policies. However, even those software products implementing rigorous security enhancements are known to be vulnerable to a broad variety of software attack methods.
Hardware-enforced one-way information flow control devices are more secure than software-based products because the hardware-enforced configuration cannot be altered by software attack, and their inherent security cannot be breached without physical access. However, conventional hardware-enforced one-way flow control has proven to be problematic for a variety of reasons. One problem has been very slow speed, e.g., as implemented in RS-232 cables with one wire clipped. The US Naval Research Laboratory produced a data diode called the Network Pump that is known to be very slow and is not purely one-way in its information flow. The Network Pump presents a reverse information flow acknowledgement of limited bandwidth. Another problem has been unreliable performance, e.g., as implemented with dubious protocol compromises or with many critical components whose combined MTBF (mean time between failure) results in short overall lifespan. Yet another problem has been the high cost, e.g., as implemented using ATM IC (asynchronous transfer mode integrated circuit) components or custom FPGA (field-programmable gate array) devices by Owl Computing Technologies™.
Therefore, there exists a need for an improved hardware-enforced one-way information flow control device.


The method of the invention recovers CO.sub.2 from an inlet cold feed stream containing a low concentration thereof, and includes the following steps. An inlet feed stream is passed through a heat exchanger, against a compressed flow of the inlet feed stream, to cool the compressed flow. The compressed flow is further cooled and compressed to a high pressure, fed to a distillation column and there converted into a vent gas including CO.sub.2 and a high purity bottom liquid CO.sub.2. A first portion of the bottom liquid CO.sub.2 is expanded to achieve a first cooled liquid CO.sub.2 refrigerant flow, which is then vaporized against the vent gas to recover condensed CO.sub.2 therefrom. The condensed CO.sub.2 is then reintroduced into the distillation column. A second portion of the bottom liquid CO.sub.2 is expanded to achieve a second cooled liquid CO.sub.2 refrigerant flow, which is then used to subcool the CO.sub.2 product output.

In conventional freezing of food with CO.sub.2, liquid CO.sub.2 is obtained from a storage tank at about 0.degree. F. and about 300 psig and is injected into a freezer. As the pressurized liquid CO.sub.2 flashes down to atmospheric pressure, it forms a mixture of solid CO.sub.2 ("dry ice") and cold CO.sub.2 vapor. The sublimation of the solid CO.sub.2 and the warming of the vapor CO.sub.2 from the sublimation temperature (-109.3.degree. F.) to the desired freezer temperature (usually between -100.degree. F. and -50.degree. F.) provide the refrigeration needed to freeze the food. The food to be frozen enters and exits the freezer continuously, and is moved through the freezer on a conveyor. After warming to the freezer temperature, the CO.sub.2 vapor leaves the freezer through the entrance and exit openings, and sometimes also through an exhaust line.
Food freezing typically requires about a one to one (1:1) ratio by weight of liquid CO.sub.2 to food. As a result, large amounts of CO.sub.2 vapor are lost to the atmosphere by conventional freezing. For example, a single standard spiral freezer unit can consume 10,000 tons of CO.sub.2 per year. The cost of CO.sub.2 represents most of the freezing cost. Recovery and recycling of CO.sub.2 from the freezer could substantially lower the cost of freezing food. Furthermore, recycling could produce environmental benefits, such as reduced CO.sub.2 emissions to the atmosphere and reduced truck transportation of liquid CO.sub.2.
Unfortunately, processes used in conventional merchant plants for liquefaction and purification of CO.sub.2 from gas streams would be uneconomical for freezer recycle. Merchant liquid CO.sub.2 is produced from industrial byproduct sources containing typically 98% CO.sub.2 (all CO.sub.2 concentrations are given in mole percentage, dry basis) and higher. In contrast, typical food freezers operate at CO.sub.2 concentrations of 40-80%, due to air infiltration through the freezer openings. The CO.sub.2 vapor exhaust is typically further diluted with room air to warm the exhaust and prevent ice build up in the exhaust system. Vent losses of CO.sub.2 from conventional liquefaction and purification processes increase greatly as the concentration of CO.sub.2 in the feed gas declines. These losses make the cost of conventional processes too high for economical use in recovering CO.sub.2 from typical freezers.
Freezers may be modified to reduce air infiltration and to supply higher CO.sub.2 concentrations to a CO.sub.2 recycle system. However, even at 90% CO.sub.2 concentration in the freezer, conventional CO.sub.2 liquefaction and purification methods would suffer losses of about 29%, which are still too large to be economical.
A simple, economical, and reliable process is needed for the liquefaction and purification of CO.sub.2 from vapor recovered during food freezing. To be economical, the process must have substantially lower losses of CO.sub.2 than conventional methods.
A conventional process for liquid CO.sub.2 production is shown in FIG. 1. A raw gas source 1 is obtained as an industrial byproduct, such as from an ammonia plant, petroleum refinery, or fermentation source. Raw gas characteristics vary, but for economical production using conventional methods, the CO.sub.2 concentration is typically above 95%. Raw gas sources are typically obtained at ambient temperature or above, and are often saturated with water. For exemplary purposes, the raw gas source 1 in FIG. 1, is assumed to contain 98% CO.sub.2 at a pressure of 20 psia and a temperature of 90.degree. F. The gas passes through heat exchanger 2 and is chilled to 50.degree. F. against ammonia refrigerant. As a result, water condenses out of the gas and is removed in separator 4.
Cooled gas stream 5 is compressed by compressor 6 to 75 psia, and the heat of compression is removed in exchanger 8. Gas stream 9 leaving exchanger 8 is cooled to 95.degree. F., which allows separation of condensed water in separator 10. Gas stream 11 is compressed by compressor 12 to about 315 psia (stream 13), cooled in heat exchanger 14 to 50.degree. F., and fed as stream 15 to separator 16 where condensed water is separated. Cooled gas stream 17 is treated by adsorbent driers 18 to remove further water to achieve a low dew point, typically about -80.degree. F. The driers operate in swing mode, with one bed in operation while the other bed is being regenerated. Dry gas stream 19 is used to provide heat to the reboiler of CO.sub.2 purification column 20. Dry gas stream 21 leaving the reboiler is now near the dew point for CO.sub.2 condensation. The dry gas 21 is partially condensed at -5.degree. F. against ammonia refrigerant in exchanger 22, providing a two-phase feed stream 23 for column 20.
Purification column 20 is a distillation column of well-known design to those skilled in the art. Typically, column 20 is a packed bed column, though other types of distillation column designs may be used. Liquid CO.sub.2 is increasingly purified as it flows down the column, and exits at the column bottom as liquid stream 27 at high purity, typically at about 99.9% CO.sub.2. Vapor stream 24 exits at the top of the column and contains all of the non-condensable portions of the raw gas feed, gases such as methane, hydrogen, nitrogen, etc. Some of the CO.sub.2 content of this vent stream is condensed against ammonia refrigerant in exchanger 25 and the CO.sub.2 liquid produced flows back into column 20 as reflux. The final vent stream 26 is released to the atmosphere.
Liquid CO.sub.2 stream 27 is often subcooled to about -20.degree. F., 305 psia, in exchanger 28 against ammonia refrigerant. This subcooling allows use of lower pressure storage vessels at production plants and minimizes vaporization of the liquid as it is pumped. After delivery to a customer site, the liquid CO.sub.2 is stored as a saturated liquid at about 295-305 psig (310-320 psia), and 0.8-2.7.degree. F. For simplicity, storage conditions at the customer site are characterized as 300 psig, 0.degree. F. herein.
The varied characteristics of raw gas sources require many variations of the conventional process described above. Some of the separation stages for removal of water may not be needed, or the pressures and temperatures may differ from the example. Also, additional unit operations are often needed for removal of contaminants such as hydrocarbons or sulfur compounds. The refrigerant used is usually ammonia or cooling water, or a combination thereof, depending on the temperature level in a particular exchanger. In addition, other refrigerants have been used, such as hydrocarbons and chlorofluorocarbons.
Not shown in FIG. 1 is a companion utility process of ammonia refrigeration, typically supplying liquid ammonia at different pressure levels to provide refrigeration at temperatures between -25.degree. F. and 100.degree. F. The design of this process is well known in the art, and is widely used in CO.sub.2 production and in many other industrial and commercial processes.
Conventional methods of CO.sub.2 liquefaction, using ammonia refrigeration at -25.degree. F., suffer increasing CO.sub.2 losses as the purity of the raw gas decreases. A typical conventional system can maintain a vent condenser temperature as low as -20.degree. F., assuming ammonia refrigeration at 1 psig, -25.degree. F. suction, and a 5.degree. F. approach in the condenser. The -20.degree. F. vent condenser temperature produces a vent composition of 73% CO.sub.2. For a typical merchant plant feed of 98% CO.sub.2, this would limit losses to 5.5% of the feed CO.sub.2 content, as shown by the -20.degree. F. temperature line in FIG. 2. However, if the feed were vapor recovered from a freezer at 90% CO.sub.2, the conventional process would suffer vent losses of 30%, making the process uneconomical. Hence, these losses make conventional processes uneconomical for recycle of recovered vapor from food freezing with CO.sub.2.
Losses of CO.sub.2 in the vent condenser may be reduced by increasing column pressure or by reducing the condensing temperature. As cited in U.S. Pat. No. 4,952,223 to Kirshnamurthy et al., increasing the pressure has disadvantages, including increased power consumption, decreased product quality, and the potential for formation of an azeotrope between CO.sub.2 and oxygen. Higher pressure would also increase the cost of the equipment. Decreasing the vent condenser temperature is a better solution.
FIG. 3 presents the vent loss (percent of the feed stream CO.sub.2 content lost in the column vent stream) as a function of the vent condenser temperature, for the case of a 90% CO.sub.2 feed stream (typical of vapor recovered from a freezer that is used as a feed for the invention disclosed below). As shown in FIG. 3, the vent condenser loss for a 90% CO.sub.2 feed stream is 30% at a conventional condenser temperature of -20.degree. F., but only 8.3% at a reduced temperature of -50.degree. F. Loss rates of up to 10% should not prevent the system from achieving economical operation, and indeed are typical of many merchant CO.sub.2 plants. The reduced loss rate achieved by a -50.degree. F. vent condenser temperature is also shown in FIG. 2 for other feed concentrations.
To achieve vent condenser temperatures below -20.degree. F. with conventional designs requires vacuum operation in the ammonia refrigeration system. Vacuum operation is undesirable, causing problems such as leakage of air into the ammonia system, larger vapor line sizes, higher power requirements, and lubrication problems. These problems increase equipment and operating costs and decrease reliability. Other refrigerants, such as chlorofluorocarbons, may be used instead of ammonia to achieve reduced vent temperatures. However, refrigeration systems employing these alternative refrigerants are more expensive, may have operational problems when employed for CO.sub.2 liquefaction, and have environmental concerns.
Conventional CO.sub.2 liquefaction methods have been applied, though without economic success, to recycle CO.sub.2 in food freezing. Duron et al., "Reliquefies CO.sub.2 For Cryogenic Freezing, Food Engineering", April 1972, p. 72-74, described a system developed for recovery, liquefaction, purification, and recycle of CO.sub.2 in food freezing. In the described system, CO.sub.2 gas was obtained from the freezer through ducts on the entrance and exit of a spiral freezer. A blower was used to transfer the gas to the recycle system. In the recycle system, the vapor was compressed, cooled, dried, treated for odor removal, condensed, and purified before returning to the freezer. Two parallel six-stage centrifugal compressors were used, with intercooling on each stage. The system used three mole sieve beds for drying and odor removal, and a four stage Freon refrigeration system. This recycle system was reported to cost $1 million in 1972.
There were several disadvantages to the Duron et al. system. The dual six-stage compressors and four-level refrigerant system were complex and expensive. The centrifugal compressors were limited in turndown and required anti-surge flow control. The estimated power requirement was very high, when compared with conventional CO.sub.2 plant power requirements of less than 200 kWh/ton. There is no indication that means were used to reduce losses of CO.sub.2 in the purification system.
U.S. Pat. No. 4,952,223 to Kirshnamurthy, et al., describes a process to recycle CO.sub.2 from food freezing using pressure swing adsorption (PSA). The process may be used for feed streams containing about 35% to 98% CO.sub.2. When used to recover CO.sub.2 from food freezers, however, the expected feed CO.sub.2 concentration is significantly less than 89% by volume and may be as low as 35% by volume. The patent states that commercial refrigeration units employing liquid CO.sub.2 for freezing foods contaminate the liquid CO.sub.2 with nitrogen and oxygen (air) to the extent that the spent CO.sub.2 vapor may contain as much as 50% or more of the contaminants. In this process, vapor drawn from the freezer is sent down a recovery line by injection of warm, pressurized air. The vapor is compressed, cooled, dried, condensed, and purified by conventional techniques. The purification column vent is treated with a PSA unit. In the PSA unit, the CO.sub.2 from the column vent is adsorbed onto a solid adsorbent. The CO.sub.2 is recovered from the solid adsorbent, at low pressure, and the low pressure CO.sub.2 stream from the PSA is recompressed with a vacuum pump and sent to the suction of the feed compressor. The PSA unit is used to reduce the very high vent loss that a conventional process would experience with such a low concentration feed gas.
Since the vapor from the freezer is further diluted with air before recovery, refrigeration content is wasted, and the injected air increases compression and purification costs. The system is complex, requiring multiple adsorbent beds operated in swing cycles, vacuum pumps, and extra compression to recover the low-pressure CO.sub.2. These factors increase the cost and reduce the operating reliability of the system.
U.S. Pat. No. 5,186,008 to Appolonia et al., discloses a method to increase the CO.sub.2 concentration in the vapor removed from a freezer for recovery, thus addressing one of the disadvantages of U.S. Pat. No. 4,952,223, above. Exhaust plenums are used on the entrance and exit of a spiral freezer, with the draw rate varied with injection rate of cryogen, to reduce air infiltration. A second blower is used to draw vapor for recovery from the freezer bottom, where the CO.sub.2 concentration is substantially higher than at the top because of density differences. The mass flow of recovery vapor is controlled to be equal to the mass flow of injected cryogen times a constant (90% is given). This is done to avoid over or under pressure in the freezer, which would expel more than a minimum amount of CO.sub.2, or would introduce too much air. The recovered vapor is to be recycled by the PSA process of U.S. Pat. No. 4,952,223.
Selective membranes may be used to reduce the loss of CO.sub.2 in the purification column vent. U.S. Pat. No. 4,639,257 to Duckett et al. proposes treating the column vent from a conventional CO.sub.2 process with a selective membrane. The vent is first heated, and then allowed to pass through a membrane unit where the CO.sub.2 selectively permeates the membrane. The high purity, low pressure CO.sub.2 permeate is then sent to the suction of the feed compressor for recovery. For low concentration feeds, a second membrane unit is proposed to increase the concentration of the feed prior to liquefaction and purification. U.S. Pat. No. 4,990,168 to Sauer et al. proposes a similar process, except that the vent stream is not heated prior to the membrane unit.
Both membrane processes suffer disadvantages. High pressures (400-415 psia) are required to feed gas to the membrane units, and the CO.sub.2 permeate is obtained at low pressure (22 psia) requiring substantial recompression. Also, membrane units are expensive and may be subject to fouling by process contaminants.
While U.S. Pat. No. 4,990,168 teaches that it is not necessary to heat the vent stream going to the membrane, and higher selectivities are achieved, the low temperatures reduce the permeability of the membrane and increase the required surface area and expense.
U.S. Pat. No. 4,977,745 to Heichberger describes a process for production of liquid CO.sub.2 from low purity sources using turbine expansion of the non-condensable impurities to provide refrigeration. The feed gas is cooled to remove water, compressed, dried, and partially condensed. The vapor from the condensation step, containing the impurities, is heated and expended in a multistage turbine expander. The cold turbine exhaust is used for refrigeration in the process, such as for the CO.sub.2 condenser.
The Heichberger process is proposed for raw gas feeds containing less than 85% CO.sub.2, particularly flue gas containing less than 50% CO.sub.2. Feed gas with more than 85% CO.sub.2 may not contain enough impurities to provide sufficient refrigeration upon expansion. While it is possible to operate food freezers at less than 50% CO.sub.2 concentration, such low CO.sub.2 concentrations in the freezer indicate air infiltration, which reduces freezer efficiency. Also, the capacity of freezer recovery units would be small compared to merchant CO.sub.2 production plants, and the cost of turbine expansion units taught in the Heichberger patent are high for such small plants. Furthermore, Brayton cycles as used in the Heichberger patent required much more energy than the Rankin cycles used in conventional merchant CO.sub.2 liquefaction. These factors tend to make the Heichberger process uneconomical for CO.sub.2 recovery from freezers.

Method for carbon dioxide recovery from a feed stream


In a video analysis device, a frame separator separates from frame images respresentative of a moving object at least first and second key frames based on either a scene change or a great movement of the object. Responsive to color and edge information, a region divider divides each key frame into region data. A vector detector applies block matching to the key frames to detect block motion vectors and detects in response to the region data of the first key frame a plurality of region motion vectors. Responsive to the region data and the region motion vectors, a correspondence establishing unit establishes correspondence between one of the region data of the first key frame and the region data of the second key frame to identify the object.

This invention relates to a video analysis method and a video analysis device for analyzing a succession of video data or images to detect a plurality of moving objects, such as up to about fifty moving objects which are moving in the video data.
Such a video analysis device is used in a monitoring system for automatically recognizing moving vehicles and walking persons. For example, a method of detecting walking persons in a cinematic sequence of frames is described by Akio Shio and Jack Sklansky in "Konpyuta Bizyon" (Computer Vision), 75-5, (1991-11-22, eight pages) as an article in the Japanese Language with an English title of "Segmentation of People in Motion" and an Abstract in English. In this video analysis method, a background image is first obtained from frame images of the sequence to extract at least two region images. By a block matching technique, motion vectors are detected in the region images. Assuming that region images of similar motion vectors represent a moving object with a high probability degree, the region images are divided into regions of walking persons.
The video analysis is recently used in editing motion video images. An example is described in a paper contributed by Hirotaka Ueda and two others to the 1993 Spring General Meeting of the Electronic Information and Communication Institute of Japan, Paper No. SD-9-1, under the English title of "Automatic Object Linkage by Video Analysis and its Application" as translated by the contributors. According to this paper, a user first specifies an object in one of successive frames. A video analysis device detects objects of identical color combinations automatically in other frames to form a hyperlink.
The technique of the Shio et al article aims at correct detection of the regions of walking persons and an accurate follow of these regions. For this purpose, it takes much time to deal with the frame images of the cinematic sequence. In order to process the frame images at a high speed, it is necessary in most cases to use specific image processing hardware.
The technique of the Ueda et al paper is featured by simple processing. This technique is, however, liable to occurrence of errors and gives results of an objectionable precision. This is because no consideration is taken on correspondence between each moving object and successive frame data.

Detection of moving objects in video data by block matching to derive a region motion vector


An exposure device sequentially transfers a pattern formed in a mask onto connected multiple regions present consecutively on a substrate through a projection optical system. The device includes a substrate stage moving in two dimensions and carrying the substrate in a movement coordinate system determined by a first axis and a mutually perpendicular second axis. A mark detecting sensor detects positions of alignment marks formed on the substrate. A magnification adjustment device corrects the magnification of the projection optical system. At least one calculating device is used to separately calculate extension amounts of the substrate in the direction of the first axis and in the direction of the second axis based on information relating to the positions of the alignment marks detected by the mark detecting sensor. An amount of magnification correction provided by the magnification adjustment device is set based on the extension amounts calculated, and scales of the first and second axes of the movement coordinate system specifying movement of the substrate stage are changed by identical amounts.

1. Field of the Invention
The present invention relates to a method of exposure and an exposure device for substrates used in manufacturing liquid-crystal display (LCD) elements and semiconductor elements. In particular, the invention concerns a method of exposure and an exposure device for forming a single device pattern by connecting multiple shots on a substrate.
2. Description of Related Art
One of the steps in manufacturing devices such as liquid-crystal displays and semiconductor elements is an exposure step in which the pattern of a reticle or mask (referred to hereinafter as a reticle) is exposed by projection onto a photosensitive substrate (referred to hereinafter simply as a substrate) such as a glass substrate or a wafer coated with resist. One method of projection exposure is known as the "step-and-repeat" method in which, after a pattern formed on a reticle has been exposed onto a specific region of a substrate, the substrate is stepped only a specific distance. The reticle pattern is then exposed again, and so on.
In exposure devices using the step-and-repeat method, to correctly position the reticle and the substrate, a reticle stage displacing the reticle within a plane perpendicular to the optical axis of the projection optical system, a substrate stage displacing the substrate within a plane perpendicular to the projection optical system, and a magnification controller controlling projection magnification of the projection optical system to project the pattern on the mask onto the substrate at a prescribed magnification are provided.
For large surface area LCDs, the LCD device pattern on the substrate is normally formed by a step-and-repeat type exposure device by picture synthesis. In picture synthesis, as shown in FIG. 7, for example, the pattern 10 of a single LCD device is divided into four patterns A, B, D, and D, and exposed. Each of patterns A, B, C, and D corresponds to a single reticle. Normally, the pattern of an LCD device including patterns A, B, C, and D is exposed onto the substrate (glass plate) using several devices at one time. FIG. 8 is an example of the formation of the device patterns 41-46 of six LCDs on a single substrate P. When manufacturing LCDs for TFTs (thin film transistors), 6-7 layers of overlay exposure are conducted during processing. This process may vary depending on device configuration. During pattern exposure, alignment marks ALM1, ALM2, . . . are also exposed. During exposure of the following layer, these alignment marks ALMn (n=1, 2, . . . ) are detected to determine subsequent shot positions.
Even when exposing a pattern such as that shown in FIG. 8 onto substrate P, due to subsequent processing, the substrate P sometimes expands nonlinearly in the manner shown by solid lines in FIG. 9, for example, and becomes deformed (FIG. 9, upper left). When the pattern of a subsequent layer, indicated by the dotted lines in FIG. 9, is overlaid and exposed onto a pattern 51-56 that has been nonlinearly deformed by processing subsequent to exposure, indicated by the solid lines in FIG. 9, a substantial overlay misalignment results in the deformed portion of the device pattern 51.
Methods of high-precision overlaying and exposure of subsequent layers of patterns on the pattern of a deformed substrate P include the enhanced global alignment (EGA) method. In this method, the regularity of a shot arrangement is specifically determined in a statistical manner. This is described, for example, in U.S. Pat. No. 4,780,617. However, in the EGA method, even though it is possible to correct for linear expansion and conduct overlay exposure, significant overlay misalignment occurs in nonlinearly deformed portions.
U.S. Pat. No. 4,833,621 is an example of a method in which the shot position is corrected for each shot, permitting good overlay exposure even when there is nonlinear deformation of the substrate. This method permits exposure while maintaining high overlay precision for each shot, and is useful when configuring one or more devices per shot, as in LSIs. However, this method is not effective for exposure methods in which a single device is configured by multiple shots, such as in picture synthesis in LCDs and the like.
FIG. 10 shows an example of overlay exposure by a method in which the shot position is corrected for each shot (A, B, C, D) as is set forth above. An LCD device pattern is formed by connecting the four patterns A, B, C, and D in a picture synthesis method. In FIG. 10, the device patterns denoted by solid lines represent previous layer patterns that have undergone nonlinear deformation. The patterns denoted by dotted lines represent exposure patterns overlaid thereon. Inspection of a device pattern 61 in the upper left portion of FIG. 10, in which nonlinear deformation has occurred, reveals that each of patterns A, B, C, and D has been overlaid with good precision onto the pattern of the preceding layer. However, picture connection errors at the borders of the synthesized patterns, such as at the border of pattern A and pattern B and the border of pattern A and pattern C, and vertical layer overlay precision errors at picture connections are substantial.
When the picture connection errors at the borders of the synthesized patterns and the overlay errors at picture connection areas are substantial, the performance of the elements formed on either side of the borderline varies greatly. As a result, lines due to variance in contrast at the borderline position appear in the finished LCD.
Further, when the substrate expands due to the effects of other processes, the magnification controller adjusts the magnification of the projection optical system. In conventional exposure devices, the combination precision between adjacent pattern regions is emphasized for each pattern of the first layer. The overlay precision relative to each pattern in the previous layer is emphasized for each pattern of the second layer and so on in the formation of LCD patterns through combination using the picture synthesis method.
In exposure of the second layer and so on, the positions of the alignment marks previously formed on the substrate during the exposure of each pattern are detected, the expansion rate in two dimensions of the substrate is calculated based on the detection results, and the projection magnification and scaling of the substrate stage are altered. The expansion rate (.gamma.X) in the X-axis direction and the expansion rate (.gamma.Y) in the Y-axis direction, which are the directions of movement of the substrate stage, are calculated, and the substrate scale of the substrate stage in the X-axis direction is changed by .gamma.X and in the Y-axis direction by .gamma.Y. The average value, m, of .gamma.X and .gamma.Y (m=(.gamma.X+.gamma.Y)/2) is set as the magnification correction value. Based on the magnification correction value, the magnification controller controls the projection magnification of the projection optical system, thereby ensuring overlay precision.
FIG. 11 shows what happens when pattern exposure from the second pattern on has been conducted by using the prior art method described above. The shot region that was originally the region denoted by dotted line S has expanded into the region S', denoted by the solid line, after exposure of the second layer due to swelling of the substrate caused by processing. In exposure from the second layer on, when the scale in the X-axis direction of the substrate stage is separately changed by .gamma.X, the scale in the Y-axis direction of the substrate stage is separately changed by .gamma.Y, and the projection magnification of the projection optical system is separately changed by (.gamma.X+.gamma.Y)/2, patterns extending beyond the individual shot regions in the X-axis direction are transferred and patterns that are narrower than the individual shot regions only in the Y-axis direction are transferred. In the Lx portion, defining a strip extending in the Y-axis direction, adjacent patterns overlap. In the Ly portion, defining a strip extending in the X-axis direction, a gap is formed between adjacent patterns.
When the overlay precision of each pattern is emphasized in this manner, the connecting portions of the first layer, that is, the pattern overlay in the Lx and Ly strip portions, changes and the characteristics of the element formed by the patterns are altered at this border. Even when these changes in element characteristics are slight, sharp changes on either side of the connecting portion of the first layer cause the changes to appear quite prominently to the human eye as a border line on the liquid-crystal display.


A method for extracting polyisoprenes from cells, comprising the steps of contacting the cells with an organic protein-denaturing compound, rupturing the cells to release the polyisoprene from the cells and recovering the polyisoprene. The preferred protein denaturing compound comprises an aqueous solution of a guanidine salt.

Natural rubber and its related polyisoprenes, gutta percha and chicle, have many uses and great commercial value. Natural rubber comprises cis-polyisoprene, while gutta percha comprises trans-polyisoprene and chicle is a mixture of the two. Rubber is the most widely used of the polyisoprenes and in many instances no completely successful synthetic substitute has been found. The balance of the present discussion is directed to the recovery of rubber, but it will be understood that the methods of the present invention are equally applicable to the recovery of all three types of polyisoprene. Hereinafter, the word rubber will be used generally to refer to all polyisoprenes that may be so recovered.
Polyisoprenes occur in many plant species in the form of sap, or latex. Table I is a list of some typical rubber, gutta percha, and chicle containing species. Latex is a white, tacky, aqueous suspension of polyisoprene globules encased in protein. The globules are of round or irregular shape, and vary in size from 0.5 to 3.0 microns in diameter.
TABLE I __________________________________________________________________________ Genus and Species Common Name Commercial Method __________________________________________________________________________ Alstonia spp. Multiple incisions Dyera spp. Single incision Funtumia elastica Multiple incisions Landolphia spp. Multiple incisions Cryptostegia grandiflora Cutting of leafless shoots Parthenium argentatum* Guayule Milling of whole plant Scorzonera tau-saghyz* Milling of roots Solidago spp.* Goldenrod Milling or solvent extraction Taraxacum kok-saghyz* Russian dandelion Milling of roots Hevea brasiliensis Para rubber tree Single incision Manihot glaziovii Ceara rubber tree Multiple incisions Castilla (Castilloa) spp. Hule tree Single incision Ficus elastica India or Assam rubber tree Multiple incisions Euonymus europaeus* Spindle tree Solvent extraction Eucommia ulmoides* Solvent extraction Cnidoscolus elasticus* Red chilte Multiple incisions Cnidoscolus tepiquensis* White chilte Multiple incisions Mimusops balata Bullet tree Multiple incisions Palaquium gutta Taban tree Multiple incisions Achras sapota Sapodilla tree Multiple incisions __________________________________________________________________________ *Temperate zone species Dyera spp. are included under rubber producers, but the polymer formed has not been characterized.
At present, natural rubber is most easily recovered from the flowing sap of rubber trees (Hevea brasiliensis), which are indigenous to tropical regions such as Brazil, Malaysia, and Indonesia. Because the latex flows within the tree, it is possible to obtain quantities of latex by simply piercing or cutting the outer bark of the tree and collecting the sap that flows from the cut. If managed properly, latex can be collected from a single tree for years without harm to the tree itself.
For collection of the rubber, latex can be concentrated by evaporation or centrifugation. Coagulation is induced by the addition of acetic acid or formic acid. Once coagulated and collected, the resulting rubber can be chemically treated, such as by vulcanization, and is suitable for many industrial, commercial and household uses.
Besides Hevea, hundreds of other species produce polyisoprenes in varying amounts, including dandelions and milkweed, as illustrated in Table I above. In these other species, the rubber is typically not as accessible as it is in the Hevea plant because it is stored within individual cells in their roots and stems. A few of these species produce commercially significant amounts of rubber, which are currently extracted by expensive and time-consuming processes.
One such species is the guayule plant (Parthenium argentatum), a desert shrub native to parts of Mexico and the southwestern United States. Since the 1940's, guayule has been selectively cultivated so that its rubber content has been greatly increased. One of the most desirable aspects of rubber-production from guayule is the ability of these shrubs to grow on arid land otherwise unsuitable for agriculture. Because guayule accumulates rubber in parenchyma cells in its stems and roots, however, it is necessary to macerate these tissues in order to obtain the rubber contained therein. Thus, the difficulty of recovery of the rubber is still a major obstacle to large-scale commercialization of the guayule rubber industry. Furthermore, guayule plants produce significant amounts of resinous material, which combines with the rubber during extraction and must be removed before the rubber can be put to commercial use.
Presently, rubber is extracted from guayule by one of two methods. The water flotation method consists of crushing and parboiling the guayule plant in water to coagulate the latex. Particles of resin-containing latex float to the surface, along with particles of plant matter. The latex can be collected and washed with acetate to remove most of the resin, following which the rubber is dissolved into hexane and then extracted therefrom by conventional separation methods. This method of rubber recovery is unsuitable in the desert environment in which guayule grows, as it entails enormous energy and water usage, as well as large amounts of organic chemical solvents.
In the second method presently used, rubber is extracted from guayule plants using organic solvents. The extraction can be either sequential or simultaneous. In both cases the guayule plant is typically frozen and pulverized or chipped into flakes. In sequential extraction, resin is removed from the flaked guayule by washing with acetone and the rubber remaining in the flakes is extracted with a nonpolar organic solvent, such as hexane or toluene. In simultaneous extraction, resin-containing rubber is extracted from flaked guayule using a nonpolar solvent. Rubber is then precipitated from the solution using a polar organic solvent such as alcohol.
Neither type of extraction has enjoyed wide-spread commercial success, as the processing steps are time-consuming, expensive, hazardous and energy-intensive. In addition, capital costs for any of the foregoing methods are large, preventing proliferation of local processing plants and therefore necessitating the transport of unprocessed guayule plants over relatively long distances. This is particularly the case where, in underdeveloped countries, industrial processing centers are typically unavailable near areas of production.
Processes are needed which avoid the disadvantages associated with conventional rubber extraction methods and which give a good yield of rubber in a short amount of time. Such processes should achieve the extraction efficiently, without the use of excessive heat or organic solvents. Additionally, such processes will preferably result in a rubber product substantially free of resins and proteins.

Method for extracting polyisoprenes from plants


Disclosed is a multi-mode/multi-band wireless transceiver. The multi-mode/multi-band wireless transceiver includes a tunable duplexer including transmission and reception channel filters of which transmission and reception channel filtering frequencies respectively are controlled by an external element; and a control portion for controlling the transmission and reception channel filtering frequencies to correspond to transmission and reception channels of a current service band. Thus, a use of a RF SAW filter is unnecessary, while it is possible to support the multi-mode/multi-band using a tunable duplexer. Therefore, the number of parts and volume of the transceiver can be reduced, and it is possible to weaken a specification of an RF system.

1. Field of the Invention
The present invention relates to a wireless transceiver, and more particularly to a wireless transceiver supporting a multi-mode/multi-band.
2. Description of the Related Art
Generally, countries all over the world employ different communication schemes for mobile communication services and each of mobile communication schemes uses various frequency bands.
The mobile communication schemes include, for example, a Code Division Multiple Access (CDMA) scheme, a Global System for Mobile (GSM) communication scheme, a General Packet Radio Service (GPRS) scheme, an Enhanced Data rates for GSM Evolution (EDGE) scheme, a Wide band Code Division Multiple Access (WCDMA) scheme, etc. in each country. The CDMA scheme uses frequency bands of 800 MHz, 1800 MHz and 1900 MHz. The GSM scheme uses frequency bands of 850 MHz, 900 MHz, 1800 MHz and 1900 MHz. The WCDMA scheme includes frequency bands of 850 MHz, 1900 MHz and 2000 MHz.
Previous wireless mobile stations have been manufactured to use signals of one or two frequency bands adapted to a specific communication service, to which a user has subscribed, among every mobile communication services. Thus, the mobile stations can only use one or two mobile communication services, among the various mobile communication services, which are used in a specific country. Therefore, when a user travels or makes a business trip to a region in which a communication service is different from that of his/her country, the use cannot use a mobile station of the region, which provides inconvenience for the user.
Thus, the user requires a mobile station capable of receiving the mobile communication service of all countries. Further, manufacturers of the mobile station need to manufacture a mobile station through which the user can use the mobile communication service in all the countries according to the user's requirement. In order to use all the mobile communication services that exist in a given country, there exists a need for a mobile station supporting multi-mode and multi-band. A term "multi-mode" means a Frequency Division Duplex (FDD) mode based on a WCDMA scheme, a Time Division Duplex (TDD) mode based on a GSM scheme, etc., while a term "multi-band" refers to different frequency bands.
It is possible to consider a multi-mode/multi-band wireless transceiver having a construction as shown in FIG. 1.
FIG. 1 shows a multi-mode/multi-band wireless transceiver, which supports two modes (i.e. the FDD mode and TDD mode), supports three service bands including WCDMA 2000, WCDMA 1900, and WCDMA 850 in the FDD mode, and supports four service bands including Personal Communication Service (PCS) 1900, Digital Cellular System (DCS) 1800, GSM 900, and GSM 850 in the TDD mode. In WCDMA 2000, WCDMA 1900, WCDMA 850, PCS 1900, DCS 1800, GSM 900 and GSM 850, the numbers 2000, 1900, 1800 and 850 represent the frequency bands of 2000 MHz, 1900 MHz, 1800 MHz and 850 MHz, respectively.
WCDMA 2000, WCDMA 1900 and WCDMA 850 respectively indicate the frequency bands of 2000 MHz, 1900 MHz and 850 MHz in the WCDMA scheme. PCS 1900, DCS 1800, GSM 900 and GSM 850 respectively indicate the frequency bands of 1900 MHz, 1800 MHz, 900 MHz and 850 MHz.
Referring to FIG. 1, an antenna 104 is selectively connected by means of a switch 106 to one of duplexers 108, 110 and 112, and a Transmitting/Receiving (T/R) switch 156. The duplexers 108, 110 and 112 separate transmitting and receiving signals of three frequency bands of WCDMA 2000, WCDMA 1900, and WCDMA 850 in the FDD mode, respectively. The T/R switch 156 switches transmission and reception relating to the frequency bands of PCS 1900, DCS 1800, GSM 900, and GSM 850.
An operation of the multi-mode/multi band wireless transceiver, in which a current service frequency band is one of the WCDMA 2000, WCDMA 1900, and WCDMA 850, and which operates in the FDD mode with relation to a reception of signal, will be described with reference to FIG. 1. Received signals introduced from the antenna 104 to the switch 106 are applied to one, which corresponds to the current service frequency band, of Low Noise Amplifiers (LNA) 114, 116 and 118 of a Radio Frequency Integrated Circuit (RFIC) 102 and amplified through one, which corresponds to the current service frequency band of the WCDMA 2000, WCDMA 1900 and WCDMA 850, of the duplexers 108, 110 and 112. The received signal amplified by each LNA 114, 116 or 118 is input to a Radio Frequency (RF) receiving portion 126 through each Radio Frequency Surface Acoustic Wave (RF SAW) filter 120, 122, or 124 which is installed outside the RFIC 102, and is converted into a baseband signal by the RF receiving portion 126, which is finally provided to a baseband processing unit 100. The baseband processing unit 100 functions as a modem for mobile communication in the case where the multi-mode/multi-band wireless transceiver is employed in a mobile station.
An operation of the multi-mode/multi band wireless transceiver, in which a current service frequency band is one of the WCDMA 2000, WCDMA 1900, and WCDMA 850, and which operates in the FDD mode with relation to a transmission of signal, will also be described with reference to FIG. 1. A baseband signal transmitted from the baseband processing unit 100 to a RF transmitting portion 128 is converted to an RF signal and then is pre-power-amplified by one, which corresponds to the current service band, of Pre-Power Amplifiers (PPA) 130, 132 and 134. The transmitted signal pre-power amplified by each PPA 130, 132, or 134 passes through one, which corresponds to the current service frequency band, of Band Pass Filters (BPF) 136, 138 and 140 and is power-amplified by each Power Amplifier (PA) 142, 144, or 146, which in turn is applied to a switch 106 through one, which corresponds to the current service frequency band, of the duplexers 108, 110 and 112. Then, the signal is transmitted by way of the switch 106 and the antenna 104.
An operation of the multi-mode/multi band wireless transceiver in which a current service frequency band is one of the PCS 1900, DCS 1800, GSM 900 and GSM 850 and which operates in the TDD mode, with relation to a reception of signal, will also be described with reference to FIG. 1. A signal introduced from the antenna 104 to the switch 106 passes through the T/R switch 156 of a PA module 154 and one, which corresponds to the current service frequency band, of BPFs 162, 164, 166 and 168 and then is applied to one, which corresponds to the current service frequency band, of the LNAs 170, 172, 174 and 176 of the RFIC 102. The signal amplified by each LNA 170, 172, 174 or 176 is input in a RF receiving portion 178 and converted into a baseband signal by means of the RF receiving portion 178. Then, the signal is provided to the baseband processing unit 100.
An operation of the multi-mode/multi band wireless transceiver in which a current service frequency band is one of the PCS 1900, DCS 1800, GSM 900 and GSM 850 and which operates in the TDD mode, with relation to a transmission of signal, will also be described with reference to FIG. 1. The baseband signal is transmitted from the baseband processing unit 100 to the RF transmitting portion 148 and then converted into a RF signal by means of the RF transmitting portion 148. Then, the RF signal is pre-power-amplified by one PPA 150 or 152 corresponding to the current service frequency band. After being power-amplified by PA 158 or 160 of the PA module 154, the amplified signal is applied to the switch 106 by way of the T/R switch 156. Finally, the amplified signal is transmitted through the switch 106 and the antenna 104.
The multi-mode/multi-band wireless transceiver constructed as shown in FIG. 1 employs a separate duplexer for each service mode or each service band in the FDD mode. This is necessary because the transceiver uses a duplexer having a fixed band for transmission/reception filtering.
Further, a separate RF SAW filter through which the service frequency band passes must be adapted to each service mode or each service band. The reason for this is because the transmitting and receiving filter of the duplexer is a band filter. The main reason for using the RF SAW filter is to decrease an interference of the transmission signal with the signal receiving band in the FDD mode.
However, since the duplexer, or SAW filter, is a band pass filter which passes the service band, it is not helpful to improve an in-band blocking characteristic or to relieve Input 3rd Order Intercept Point (IIP3) and Input 2nd Order Intercept Point (IIP2) characteristics of a mixer which converts the received signal into a low band in the RF receiving portion. Thus, it is difficult to relax a specification of the RF system.
Further, since a separate duplexer and the RF SAW filter are used in every service mode or in every frequency band, respectively, they are a burden to the transceiver in view of cost, volume and required mounting area. Specially, an active element tends to have a gradually smaller size as circuit technology has been developed. However, since an inactive element, such as RF SAW filter, still does not have a small size, it is a burden to the transceiver.
In the case of supporting all the different service modes, such as FDD and TDD, since a duplexer for the FDD mode and a T/R switch for T/R switching must be separately used in the transceiver, they are a burden to the transceiver in view of cost, volume and required mounting area of the transceiver.


A latch assembly combination having: a) a first plate assembly; b) first and second axles extending from the first plate assembly; c) a rotor mounted to one of the first and second axles for guided pivoting movement between latched and released positions; d) a catch mounted to the other of the first and second axles for guided pivoting movement between: i) an engaged position wherein the catch blocks the rotor in the latched position; and ii) a disengaged position wherein the rotor is allowed to reposition; e) a biasing assembly for urging the rotor toward the released position; and f) at least one of: i) a second plate assembly that can be selectively operatively joined to the first plate assembly in first and second different manners; and ii) third and fourth plate assemblies of different configuration that can be selectively operatively joined to the first plate assembly.

1. Field of the Invention
This invention relates to latch systems for releasably maintaining a repositionable closure element in a predetermined position relative to a support therefor and, more particularly, to a latch assembly having a housing with a repositionable rotor thereon for engaging a strike element with the housing and strike element mounted one each on the support and closure element.
2. Background Art
There is a multitude of latch assemblies currently in existence that use a cooperating strike element and rotor to releasably maintain a movable element, such as a closure element, in at least one predetermined position, relative to a support upon which the closure element is mounted. This combination is used in many different industries and environments for both static and dynamic applications.
Typical of this construction is the use of a housing that supports cooperating rotor and catch components. The rotor is repositionable relative to the housing between a latched position and a released position and is spring biased normally towards the latter. As the closure element is moved towards the predetermined position therefor, the strike element interacts with the rotor and causes the rotor to be moved from the released position into the latched position, as an incident of which the strike element becomes captive in a receptacle defined by the rotor. A catch engages the rotor to maintain the rotor in the latched position and is repositionable to allow the rotor to be moved under the spring bias force back into the released position, whereupon the closure element can be moved out of the predetermined position therefor.
Typically, the basic components of the latch assembly are pre-assembled as a module that can be integrated into an actuating system that will ultimately be used to change the rotor from the latched position into the released position therefor. Suppliers of these types of systems encounter demands for myriad different module configurations, depending upon the mounting requirements and nature of the actuating system. As just examples, certain applications require left-handed operation while others require right-handed operation. Repositioning of the rotor through the actuating system may require the direct application of a force on an actuator element that is directly on the housing or upon an actuator assembly that is remote from the housing. The operation of the actuating system may be manually performed or may rely on powered components. Within each of these variations is a further subset of multiple different structures.
Heretofore, each latch assembly module has been custom designed. Latch assembly modules with specific characteristics and features are constructed using a dedicated supply of components, typically including: a) a specific housing; b) a pair of axles; c) a particular "handed" rotor; d) a particular "handed" catch; and e) one or more springs for producing the normal bias on the rotor. These components will normally be stocked in a manner that they can be serially picked and assembled on a dedicated line. Thus, each particular module configuration requires its own dedicated stock of components that is combinable in a consistent manner. Generally, the only components that are practically interchangeable, to be crossed over from one module design to the next, are the axles.
By reason of custom designing and assembling individual modules, there are a number of inherent inefficiencies, from the standpoint of tooling, required stocking and assembly space, manning of assembly lines and inventory control. Generally, manufacturers will keep on hand components for a particular module based upon anticipated demand. By doing so, orders can be filled promptly. However, demand for particular types of modules may fluctuate significantly, as result of which an excess of one particular design may be on hand while there is a shortage of another design. The only way to promptly meet customer demand is to keep on hand an excess of each different module design. This may lead to a significant stock of unused inventory. This is a problem not only from the standpoint of the financial investment, but also from the standpoint that the components and/or assembled modules must be stored.
Further, over time, demand for a certain design of module may decrease, whereupon the inventory of the particular design may remain stagnant and ultimately may have to be disposed of with significant financial consequences.
Also, as noted above, if the manufacturer offers, for example, ten different module constructions, ten different set-ups or lines may be required in the manufacturing facility. This may take up a significant amount of valuable facility space. Manning of these multiple lines may introduce other inefficiencies, potentially both from the standpoint of inefficient personnel time usage and excess personnel.
Aside from space and manning issues, the engineering, tooling and set-up costs increase with the number of parts and model variations. Preparatory to final design manufacture, each latch assembly version must be prototyped and tested to avoid potentially unforseen manufacturing or performance problems. All the above considerations potentially also lead to a delay in introducing a product to market.
The industry continues to seek out latch assembly designs that can be efficiently manufactured to allow suppliers to offer a line of high quality latch assembly products that meet a wide range of customer needs and demands at competitive pricing.

Latch assembly with selectively assembled components


A method for detemiining fringing capacitances on passive devices within an integrated circuit is disclosed. A fringing capacitance region on a passive device is initially divided into a group of fringing electric field areas. A set of fringing capacitance equations is then developed for the fringing electric field areas accordingly. A determination is made as to whether or not an accuracy of the fringing capacitance equations meets a predetermined threshold. If so, then the fringing capacitance equations are utilized in compact device models to determine fringing capacitance on the passive device; otherwise, the physically-based fringing capacitance equations are fitted to a set of extracted data to generate a refined set of physically-based fringing capacitance equations, and the refined set of physically-based fringing capacitance equations is utilized in compact device models to determine fringing capacitance on the passive device.

1. Technical Field
The present invention relates to software tools in general, and, in particular, to a method within a software tool for verifying integrated circuit designs. Still more particularly, the present invention relates to a method within a software tool for determining fringing capacitances on single-layer and multi-layer on-chip passive devices.
2. Description of Related Art
On-chip passive devices can have a single or multiple back-end of the line (BEOL) metal layers. Currently, some foundry offers passive on-chip devices as a part of its design kits. Such passive on-chip devices can be spiral inductors (including multi-layer stacked inductors), transmission lines (microstrip and co-planar waveguide inter-connects including stacked metal line over a silicon substrate), bond pads and capacitors (MIM and vertically stacked parallel-plate). Each passive device is supported by schematic symbol, layout parameterized cell (Pcell), design rule checking (DRC), extraction and layout versus schematic (LVS) decks as well by a compact model that allows both time-domain and frequency-domain simulations such as parametric, temperature dependence and Monte-Carlo runs.
Whenever possible, it is very important to have analytical equations for the area, fringing and mutual capacitances of the on-chip passive devices. Although area capacitance calculations are usually quite straight-forward, the generation of analytical equations for fringing and mutual capacitances tends to be more difficult. Nevertheless, all capacitance terms (i.e., area, fringing and mutual) are required by any compact device model.
There are many drawbacks associated with the prior art methods of calculating fringing capacitance. For example, polynomial-based fringing capacitance equations are not always physically based; thus, the initial errors in polynomial fitting procedure can be relatively large, which may cause problems in accuracy and stability of a numerical convergence, etc. Consequently, it would be desirable to provide an improved method for determining fringing capacitances on on-chip passive devices.

Method for determining fringing capacitances on passive devices within an integrated circuit

International Business Machines Corporation


Disclosed is a process for preparing a cathode structure for impregnated cathodes having desired dimensions by a simplified process without experiencing machining etc. A high-melting-point metal powder is introduced into a mold, and heated with the heater to effect isostatic press molding to provide a cathode structure for impregnated cathodes having a predetermined shape and dimensions by one operation.

1. Field of the Invention
This invention relates to a process for preparing a cathode structure for impregnated cathodes used in electric discharge tubes.
2. Description of the Prior Art
Cathode is an essential constituent of electric discharge tubes, upon which efficiency and life of the electric discharge tubes are decided. Characteristics required for the cathodes for electric discharge tubes are as follows:
(a) high electron emission efficiency;
(b) high current density;
(c) uniform emission energy;
(d) stable operation;
(e) long life;
(f) sufficient resistance to the vacuum pressure imparted to the electric discharge tube; and
(g) no electron emission at any part other than the predetermined electron emitting surface.
Impregnated cathodes can be given as those having the above-described characteristics.
An impregnated cathode is prepared by impregnating a porous high-melting-point metal base such as of porous tungsten with an electron emitting material comprising a compound oxide based on barium. The thus prepared impregnated cathode is usually mounted on a heater sleeve with a heater accommodated therein. During operation of the cathode, the compound oxide impregnated in the porous metal base is heated by the heater and reduced at the activation temperature into free metals which diffuse throughout the surface of the porous metal base and form a single atomic layer. The thus formed single atomic layer is designed to have greatly reduced work function compared with the tungsten, enabling efficient electron emission.
The cathode structure for such impregnated cathodes has conventionally been prepared in the following manner:
(a) a high-melting-point metal powder is shaped by powder extrusion method and then sintered;
(b) the thus sintered porous high-melting-point metal is infiltrated with an acrylic resin as a lubricant so as to facilitate machining thereof;
(c) upon completion of machining into predetermined dimensions of cathode base, the infiltrated acrylic resin is removed; and
(d) the cathode base is soldered or welded onto a heater sleeve.
As described above, fabrication of a cathode structure for impregnated cathodes requires such considerable time, equipments and materials.
According to the above prior art method, an impregnated cathode can be obtained through a long process (molding and sintering.fwdarw.acrylic resin infiltration.fwdarw.machining.fwdarw.acrylic resin removal.fwdarw.bonding), leading to increase in the manufacturing cost and facility cost, disadvantageously. Meanwhile, shaping of the porous high-melting-point metal base includes a molding step and a sintering step, increasing the working time, and besides deformation which occurs during sintering makes it difficult to obtain a desired size of product.

Preparation of cathode structures for impregnated cathodes


A tilt cylinder apparatus for a boat propeller unit comprising a cylinder unit containing an inside cylinder and an outside cylinder, an opening portion of the cylinders being closed by rod guides, a piston which is connected to an end of a piston rod placed through the rod guides and disposed slidably in the inside cylinder, a reservoir chamber which is formed between the inside cylinder and the outside cylinder and contains a fluid chamber and an air chamber, a communicating path which is formed in the rod guides and ensures a communication between the rod side chamber and the reservoir chamber through a conduit pipe disposed in the reservoir chamber, and a selecting valve which is disposed in the rod guides and selects an opening or closing of the communicating path following an outside operation, wherein when the communicating path is opened, air pressure in the air chamber of the reservoir chamber pushes the piston rod out of the cylinder unit so as to tilt up the boat propeller unit.

1. Field of the Invention
This invention relates to a tilt cylinder apparatus for use in an outboard motor or the like.
2 . Discussion of the Background Art
The tilt cylinder apparatus for use with a boat propeller unit, for example, an outboard motor, is disposed between the boat body and an outboard motor tiltingly supported by the boat body, and is used for tilting the outboard motor by extending the cylinder apparatus.
The aforementioned tilt cylinder apparatus for boat propeller has been disclosed in U.S. Pat. No. 3,990,660 (first prior art reference) and Japanese Patent Application publication (JP-B) No.2-58155 (second prior art reference).
The first prior art will be described in detail. An interior of the cylinder is sectioned to a rod side chamber containing a piston rod and a piston side chamber not containing the piston rod, by means of a piston. An air chamber is provided in the piston side chamber of the cylinder across a free piston. The rod side chamber communicates with the piston side chamber through a communicating path formed in the piston. A selecting valve for selecting an opening/closing of this communicating path is disposed in this piston. A function of tilting up the propeller unit is executed by opening the selecting valve by operating an operating rod provided in the piston rod so as to ensure communication between the piston side chamber and the rod side chamber through the communicating path, and move the piston to the rod side chamber by an action of air pressure in the air chamber so as to push the piston rod out of the cylinder.
According to the second prior art reference, the interior of the cylinder is sectioned to the rod side chamber and the piston side chamber by the piston. The air chamber is provided in the piston side chamber of the cylinder. A communicating path between the rod side chamber and the piston side chamber is opened or closed by means of the selecting valve. The communicating path and the selecting valve are provided outside the cylinder. The aforementioned function of tilting up the propeller unit is executed by opening the communicating path by operating the selecting valve so that the piston is moved to the rod side chamber by action of air pressure in the air chamber, thereby pushing the piston rod out of the cylinder.
According to the first prior art reference, the air chamber is provided in the cylinder and the communicating path and the selecting valve are disposed in the piston. As a result, a compactness of the apparatus is achieved. However, because the operating rod for operating the selecting valve is disposed within the piston rod and an operating portion of the operating rod is located at an end of the piston rod so that the operating rod is apart from the boat body, the operability of the selecting valve, that is, the operability of the apparatus is reduced.
According to the second prior art reference, because the communicating path and the selecting valve are disposed outside the cylinder, a position of the operating portion of the selecting valve can be determined arbitrarily. However, because the communicating path and the selecting valve are disposed outside the cylinder, enlargement of the apparatus is unavoidable.

Tilt cylinder apparatus for boat propeller unit


A video converter converts an input video signal conveying pixel data representing an M.times.K pixel image to an output video signal conveying data representing an N.times.L pixel image. The converter samples the input video signal to acquire an M.times.K matrix of pixel data, re-encodes each pixel data value as necessary to meet color coding requirements of the output video signal standard, and then employs digital interpolation and/or decimation filters to convert the M.times.K data matrix to an N.times.L data matrix. A simple digital output encoder operating at four times the output video signal subcarrier frequency is then employed to process the N.times.L matrix to produce a digital output data sequence which, when applied to D/A converter, becomes the output video signal.

1. Field of the Invention
The present invention relates in general to video signal conversion systems and in particular to a video conversion system that selectively alters the dimensions of an image conveyed by an input video signal when converting the input video signal to an output video signal of differing format.
2. Description of Related Art
An image formed by K rows of pixels, with M pixels per row, may be represented by an M.times.K data matrix having elements of the form X(m,k) where each element represents the color of the mth pixel of the kth row of the image. Elements of such a data matrix can be sequentially encoded into analog signals and mixed with a subcarrier to produce a video signal for conveying the image data, for example, to a display monitor. There are many standards for video signals including, for example, devices which generate video signals following an RGB standard where each element X(m,k) of the data matrix has three values (R,G,B) representing intensities of red, green and blue components of the pixel's color. The PAL and NTSC television systems employ a video signal standard where each matrix element has three values (Y,U,V) where Y is luminance and the U,V data pair defines chrominance. The manner in which data is encoded into the analog video signal, the rate at which pixels are generated on a display (the scan rate), and the video signal subcarrier frequency may differ from one video signal standard to the next.
A video converter receives an input video signal and converts it to an output video signal. In the process, the converter may have to change several aspects of the input video signal including the color encoding scheme, the pixel dimensions of the images, the manner in which the pixel data is encoded into the video signal and the subcarrier frequency.
U.S. Pat. No. 5,526,055 issued Jun. 11, 1996 to Zhang et al describes two similar systems for converting an RGB-encoded video signal to a YUV encoded video signal: a system that is prior art to Zhang's system, and Zhang's system that is a modification to the prior art system. In the prior art system, the RGB video signal is digitized to produce a pixel data sequence which is re-encoded into YUV format and then stored in a memory. The resulting data sequence is then read out of the memory and supplied to an analog signal encoder. The encoder converts the data sequence to analog signals and mixes them with a clock signal oscillating at the output video signal subcarrier frequency to produce the output video signal. As the encoder mixes the analog video data with the subcarrier, it alters the pixel dimensions of the image to match the output video signal standards. Zhang modified the prior art video converter essentially by substituting a digital encoder for the analog encoder. Zhang's digital encoder is rather complex since it must include digital sine and cosine wave generators, multipliers and other components. In either video conversion system it is necessary to closely couple the subcarrier frequencies of the input and output video signals using relatively complicated timing systems employing phase lock loop circuits which may require discrete components.
What is needed is a video converter which can convert an input color video signal representing an input image to an output color video signal representing an output image where the pixel dimensions of the input and output images differ, where the color encoding schemes employed by the input and output signals differ, and where the subcarrier frequencies of the two signals differ. In addition, the video converter should not require the use of several phase lock controllers or complicated analog or digital encoders.

Video signal converter utilizing a subcarrier-based encoder


A method for determining whether a terminal is located inside a discovered Secure User Plane Location Platform (D-SLP) service area is disclosed. The method may comprise identifying a discovered Secure User Plane Location Platform (D-SLP). A terminal may receive from a home Secure User Plane Location Platform (H-SLP) an authorization to use the D-SLP. Additionally, the terminal may receive from the H-SLP a list of Area IDs within a Secure User Plane Location Platform (SLP) service area comprises a first group of Area IDs within the SLP service area. The method may comprise comparing an ID associated with a network access point for the terminal, and the list of Area IDs to determine if the terminal is inside the D-SLP service area. The method may comprise making a D-SLP use determination based on the comparison.

Aspects of the disclosure relate to location-based services for mobile wireless devices. In particular, various aspects of the disclosure relate to Secure User Plan Location (SUPL) technology.
Location services for mobile wireless devices enable the current location and optionally speed and heading of a mobile wireless device to be obtained and provided to the wireless device (e.g., to an application running on the wireless device or to the user of the wireless device) or to some third party. Examples of a third party may include an emergency services provider (e.g., in the case of an emergency call from the wireless device) or some external provider of commercial services that depend on knowing the current or previous location of the wireless device. For wireless devices that may access different types of wireless communication networks, location services may be supported using a location server that can be accessed from and, in some cases, may be resident within the wireless network currently being accessed by the wireless terminal. The role of the location server may be (i) to assist the wireless terminal to make appropriate location related measurements (e.g., measurements of radio signals from base stations in the serving wireless network or measurements of various global navigation satellites) and, in some cases, (ii) to compute the location of the wireless terminal based on these measurements. The location server may also be used to relay a wireless device's location to entities authorized to receive the location and convey the wireless device's location to the wireless device in the event that the location server, rather than wireless device, had computed the location.
Current user plane location services, such as the Secure User Plane Location (SUPL) service defined by the Open Mobile Alliance (OMA), derive their security from mutual authentication between a target mobile device (e.g., a SUPL Enabled Terminal (SET)) and a location server (e.g., a SUPL Location Platform (SLP)) in which each party verifies the identity of the other party in a fully reliable manner.
A home location server (e.g., a Home SLP (H-SLP) in the case of SUPL) is a location server permanently affiliated with a number of target devices (e.g., based on service subscription). A home location server would sometimes belong to a home network operator of the target device, in the case of mobile wireless devices. A location server without a pre-provisioned permanent affiliation with a set of target devices may be referred to as a discovered location server.
In the case of SUPL, a discovered location server is referred to as a Discovered SLP (D-SLP). A discovered location server can be found by, or provided to, a target device based on its current location, currently used access network(s) and/or the current date and time and could belong to or be associated with, a non-home network operator or some other non-operator provider of location services. A Discovered SLP (D-SLP) is an SLP able to provide service to a SET in areas where the H-SLP is unable to provide service or unable to provide service at the requested quality of service (e.g., accuracy, time to fix).
In some instance (i.e., certain locations or environments), a H-SLP may not be able to adequately aid the SET in positioning (e.g., provide appropriate assistance data, perform positioning calculation, etc.). In these instances, a D-SLP may have a better ability than the H-SLP to aid the SET in positioning (e.g., provide appropriate assistance data, perform positioning calculation, etc.). In such instances a D-SLP may be used to provide unproved (e.g., localized) location service to a SET. A H-SLP may negotiate with a D-SLP to allow a SET to have access to the D-SLP. When a SET discovers a D-SLP, the SET may query its H-SLP for access rights to that D-SLP through an authorization process.
After D-SLP Authorization by an H-SLP, a SET may only be allowed to access the D-SLP while within the D-SLP service area. To this end, the SET needs to be able to determine whether it is inside or outside the D-SLP service area. This requires the SET to continuously monitor its position relative to the D-SLP service area by using high accuracy positioning methods. This continuous monitoring typically increases the power consumption of the SET and may more quickly drain the battery of the SET. Therefore, the continuous monitoring using precise positioning can reduce standby and usage time.

D-SLP service area detection using area ID


A turbine engine includes an electrical system having at least two generator circuits, one coupled to a high pressure portion of a gas turbine engine and the other coupled to a low pressure portion of the gas turbine engine. The electrical system actively cools an electrical generator during operation in order to ensure proper operation as well as extend the lifespan of the generator.

It has become increasingly desirable to improve the overall system design and operation of gas turbines. In a system having a typical gas turbine engine, electrical power is extracted via an electrical generator to supply electrical power to control systems, actuators, weapons systems, climate control systems, and the like. Electrical storage, such as a battery, is typically provided to operate such systems when the gas turbine engine is not running or to provide power for starting the gas turbine engine. In some known gas turbine engines, the gas turbine engine includes a high pressure shaft and a lower pressure shaft, and the electrical generator is coupled to one of the high and low pressure shafts.
The electrical generator commonly generates thermal energy when in operation. It is important to actively cool the electrical generator during operation in order to ensure proper operation as well as extend the lifespan of the generator. This is commonly accomplished through the use of a fan attached to the generator shaft. The fan adds undesirable weight and complexity to the generator. In addition, when the generator is operating at altitude in an aircraft there becomes a reduction in air density. This results in a reduction in air-flow, which in turn reduces cooling. Increasing fan velocity may be utilized to partially address these losses, but is not always efficient or practical.
Overcoming these concerns would be desirable, could improve generator efficiency, and could save the industry substantial resources.

Generator with controlled air cooling amplifier


A nematic liquid crystal composition of the present invention includes 10 to 80% by mass of either one or at least two compounds represented by general formula (I) as a first component; and 20 to 70% by mass of either one or at least two compounds represented by general formula (II) as a second component, wherein a dielectric constant anisotropy is negative.

Liquid crystal display elements have been used for various electrical household machineries and equipment such as a clock and a calculator, measuring equipments, panels for automobile, word processors, electronic notes, printers, computers, televisions, and the like. Typical liquid crystal display systems include TN (twisted nematic) type, STN (super twisted nematic) type, DS (dynamic light scattering) type, GH (guest-host) type, IPS (in-plane switching) type, OCB (optically compensated bend) type, ECB (electrically controlled birefringence) type, VA (vertical alignment) type, CSH (color super homeotropic) type, FLC (ferroelectric liquid crystal), and the like. Moreover, regarding a driving system, multiplex driving system has become typical from conventional static driving system, and simple matrix systems and recently active matrix (hereunder, referred to as "AM") systems in which driving is performed by TFT (thin film transistor), TFD (thin film diode), and the like, have been in the mainstream.
In these display systems, IPS type, ECB type, VA type, CSH type, and the like are different from TN type and STN type which are currently used for general purpose, and are characterized in that liquid crystal materials having a negative dielectric constant anisotropy (Δ∈) are used. Of these, in particular, VA type display by means of AM driving is the most expected type at present in the application to display elements that require high-speed and wide-field angle, such as a television.
For liquid crystal materials used for display systems such as VA type, a low-voltage driving property, quick responsiveness, and a wide operating temperature range are required. That is, a negative dielectric constant anisotropy of a large absolute value, a low viscosity, and a high nematic phase-isotropic liquid phase transition temperature (Tni) are required. Therefore, in order to realize quick responsiveness, an attempt has been made to reduce the cell gap of display elements. However, in order to optimally set the retardation represented by the product (Δn×d) of the refractive index anisotropy (Δn) and the cell gap (d), the refractive index anisotropy and the cell gap of a liquid crystal material have to be adjusted within appropriate ranges. Accordingly, narrowing of the cell gap has been limited. In order to improve the response speed without changing the cell gap, it is effective to use a liquid crystal composition with a low viscosity. If a liquid crystal display element is applied to a television or the like, since quick responsiveness is prioritized, the development of liquid crystal compositions having a low viscosity has been particularly in demand.
As a liquid crystal material having a negative dielectric constant anisotropy, liquid crystal compounds having a 2,3-difluorophenylene structure as follows are disclosed (refer to Patent Documents 1 and 2).
(wherein R and R′ represent an alkyl group or an alkoxy group of 1 to 10 carbon atoms).
Furthermore, in these cited documents, compounds having a 1-hydroxy-2,3-difluoro-4-substituted benzene structure are disclosed. However, the compounds described in the cited documents are comprehensive in a wide range, and there is no specific disclosure of a compound having alkenyl groups at the both side chains. With liquid crystal compositions having a negative dielectric constant anisotropy using the described compounds, a sufficiently low viscosity has not been realized yet in liquid crystal compositions in which quick responsiveness is required for a liquid crystal television or the like.
On the other hand, there are disclosures of liquid crystal compositions using compounds having a 1-hydroxy-2,3-difluoro-4-substituted benzene structure serving as a basic structure of a liquid crystal compound constituting the invention of the present invention (refer to Patent Documents 3, 4, and 5). However there is no specific disclosure of a liquid crystal composition using a compound having alkenyl groups at the both side chains, and there is no specific disclosure of the type of compound to be used in addition to the concerned compound so as to reduce the viscosity of the liquid crystal composition.
Moreover, liquid crystal compounds having a 2,3-difluorohydroquinone structure have been already disclosed (refer to Patent Documents 6 and 7), and liquid crystal compositions using the concerned compound have been also disclosed. However, the concerned compound has a hydroquinone structure, and thus is considered to be unusable for an active matrix in the point of the voltage-holding ratio (refer to Non Patent Document 1), delaying the development of a liquid crystal composition having a low viscosity for VA using the concerned compound.
Accordingly, the development of a liquid crystal composition having a negative dielectric constant anisotropy with a low viscosity is desired.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. S60-199840
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. H2-4725
[Patent Document 3] Japanese Unexamined Patent Application, First Publication No. H8-104869
[Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2000-96055
[Patent Document 5] European Patent Application, Publication No. 0474062 (page 14)
[Patent Document 6] Published Japanese Translation No. H2-503568 of the PCT International Publication
[Patent Document 7] German Patent Application, Publication No. 3906058
[Non Patent Document 1] Hiroshi Numata, Monthly Display, Vol. 4, No. 3, pp, 1-7, (1998) (page 5, Table 4)

This patent is subject to a terminal disclaimer.

Difluorobenzene derivative and nematic liquid crystal composition using the same

Abstract: The use of this nematic liquid crystal composition can provide a highly reliable liquid crystal display element capable of maintaining a high voltage-holding ratio even in a high temperature region, and achieving quick responsiveness without reducing the cell gap.


Electron beam modulation in response to optical pump pulses applied to a sample is measured using SPAD elements. Individual detection events are used to form histograms of numbers of events in time bins associated with pump pulse timing. The histograms can be produced at a SPAD array, simplifying data transfer. In some examples, two SPAD arrays are stacked and a coincidence circuit discriminates signal events from noise events by determining corresponding events are detected within a predetermined time window.

Conventional time-resolved electron microscopy revolves around synchronizing a pump pulse such as a laser pulse, a microwave pulse, a temperature pulse, a mechanical or other excitation to start a sample probing process. Typically, the pump pulse is directed to a sample to interact with the sample and initiate a sample response. A probe pulse is then directed to the pumped sample and response to the probe pulse is measured. Temporal response can be obtained by varying the temporal delay of the probe pulse with respect to the pump pulse. The probe pulse can be an electron beam pulse produced in response to the pump laser, often by frequency doubling the pump pulse, and generating an electron beam pulse in response to the frequency doubled pump pulse. Pulse/probe pulses are repeated to permit increasing signal-to-noise ratio and varying the pulse/probe temporal delay permits reconstruction of sample temporal response. These pump/probe measurements can require lengthy acquisition times to provide adequate signal-to-noise ratio. In addition, the electron beam modulation and associated temporal delay complicate measurement setup.
Certain electron detectors can provide high temporal resolution but exhibit high noise so that signal to noise ratios are low. For example, single photon avalanche detectors (SPADs) can produce an avalanche-based output signal in response to a single electron. Unfortunately, SPADs also produce output signals (dark counts) in the absence of electron beam input. These dark counts can be reduced by SPAD cooling but cannot be distinguished from real signal.
In view of the above, alternatives to conventional pump/probe measurement approaches are needed as well as alternative detector configurations.

Time-gated detection, dual-layer SPAD-based electron detection


The invention thus provides a core-shell polymer comprising a core phase which is rubbery polymer and a shell phase which is a glassy polymer with an unsaturated dicarboxylic acid or its mono-alkyl ester as a constituent thereof, wherein the toluene-soluble fraction of the core-shell polymer accounts for not more than 10% by weight.. It also provides polyamide resin compositions comprising said core-shell polymer and molded articles produced by molding said compositions.. The resin compositions and molded articles which comprises the core-shell polymer as an impact modifier have good features, especially a high impact strength at temperature ranging from room temperature to -30.degree. C.

Polyamide resins have excellent thermal deformation resistance, rigidity and oil resistance and are used in electric appliance parts and automobile parts. Further improvement in impact strength and water resistance is desired, however.
As regards the impact strength, in particular, various attempts have already been made, including, more specifically, the use of ABS resins and modified polyolefins.
On the other hand, impact modifiers of the core-shell polymer type have been proposed, with a rubbery polymer as the core and a glassy polymer as the shell. Impact modifiers of this kind show good dispersibility in resins and it is relatively easy to attain reproducibility from the morphology viewpoint.
A core-shell polymer for improving the impact strength of polyamide resins has already been proposed in U.S. Pat. No. 3,668,274, which polymer contains carboxyl groups in the shell phase. Compositions composed of this carboxyl-modified core-shell polymer and nylon 6 indeed show good notched Izod impact strength values (thickness: 1/8 inch) at temperatures not lower than 23.degree. C. but still have problems: the impact strength improving effect is low and the melt viscosity is high. The latter fact offers a problem from the moldability viewpoit. Furthermore, said impact modifier shows a very poor improving effect in nylon 66.

Core-shell polymer, resin composition and molded article thereof