Methods are disclosed for preparing a highly active solid metallocene-containing catalyst system and its use in the polymerization of olefins. The catalyst system is prepared by creating a catalyst system solution by combining an aluminoxane with a metallocene having a substituent which has olefinic unsaturation in a suitable liquid to form a liquid catalyst system, conducting prepolymerization of an olefin in the liquid catalyst system, and separating the resulting solid metallocene-containing catalyst system from the reaction mixture. Also polymerization of olefins using the inventive solid catalyst system is disclosed.

The term "Metallocene" as used herein refers to a derivative of cyclopentadienylidene which is a metal derivative containing at least one cyclopentadienyl component which is bonded to a transition metal. The transition metal is selected from Groups IVB, VB, and VIB, preferably IVB and VIB. Examples include titanium, zirconium, hafnium, chromium, and vanadium. A number of metallocenes have been found to be useful for the polymerization of olefins. Generally, the more preferred catalysts are metallocenes of Zr, Hf, or Ti.
Generally, in order to obtain the highest activity from metallocene catalysts, it has been necessary to use them with an organoaluminoxane cocatalyst, such as methylaluminoxane. This resulting catalyst system is generally referred to as a homogenous catalyst system since at least part of the metallocene or the organoaluminoxane is in solution in the polymerization media. These homogenous catalysts systems have the disadvantage that when they are used under slurry polymerization conditions, they produce polymer which sticks to reactor walls during the polymerization process and/or polymer having small particle size and low bulk density which limits the commercial utility.
Some attempts to overcome the disadvantages of the homogenous metallocene catalyst systems are disclosed in U.S. Pat. Nos. 5,240,894; 4,871,705; and 5,106,804. Typically, these procedures have involved the prepolymerization of the metallocene aluminoxane catalyst system either in the presence of or in the absence of a support. An evaluation of these techniques has revealed that there is still room for improvement, particularly when the catalyst is one which is to be used in a slurry type polymerization where the object is to produce a slurry of insoluble particles of the end product polymer rather than a solution of polymer which could result in fouling of the reactor. In the operation of a slurry polymerization in a continuous loop reactor it is extremely important for efficient operations to limit polymer fouling of the internal surfaces of the reactor. The term "fouling" as used herein refers to polymer buildup on the surfaces inside the reactor.
U.S. Pat. No. 5,498,581 discloses a technique for producing insoluble polymerization catalysts by combining a metallocene having polymerizable groups with an aluminoxane and a particulate solid and then prepolymerizing. PCT /US96/13000, the disclosure of which is incorporated herein by reference, and a commonly owned copending application disclose that at least one such catalyst is capable of producing polyethylenes having ethyl branches which are uniformly distributed at the intra and intermolecular level without using any comonomer.
An object of the present invention is to provide a method for producing an insoluble polymerization catalyst that is capable of producing even more ethyl branches without the addition of comonomer. Another object of the present invention is to provide a process for producing polyethylene having unusually high levels of ethyl branches without the use of a comonomer. Still another object of the present invention is to provide polyethylenes that are particularly useful for making films of unusual clarity at a given density, said polyethylenes having a very narrow molecular weight distribution and no detectable amounts of long chain branching.
Another object of the present invention is to provide polyethylene having ethyl branches wherein the level of ethyl branches is substantially the same regardless of the molecular weight of the polymer molecules.
Another object of the present invention is to provide certain types of polyethylene having ethyl branches wherein the molar percent of ethyl branches is substantially the same for molecular fractions across the molecular weight distribution of the polymer. One type of such polyethylene is substantially free of any other type branches. In a preferred embodiment the polyethylene is substantially free of branches having 6 or more carbon atoms.
Another object of the present invention is to provide certain polyethylene having significant amounts of terminal vinyl groups, a very narrow molecular weight distribution, and a lower density than one would normally expect for the amount of branching due to comonomer insertions in the polymer chains.
Another object of this invention is to provide certain narrow molecular weight polyethylenes having an unusually low density for the amount of short chain branching at a given molecular weight. Still another object is to provide polyethylene films having a desirable combination of properties.

Method for making and using a supported metallcene catalyst system


A method and apparatus to facilitate managing communications with at least one wireless node (102, 103) having an outbound payload memory in a severely resource-constrained wireless network (100) can provide for a coordinator node (101) for that network providing (201) information regarding remaining capacity of those outbound payload memories and then automatically using (202) that information in integral combination with a bandwidth allocation management process to control allocation of at least one wireless communication resource by which the wireless nodes can transmit items contained in the outbound payload memory.

Wireless communications networks of various kinds are known in the art. In some cases, as with some wireless sensor node networks, the network comprises a severely resource-constrained wireless network. In some cases, such constraints may comprise hardware resource constraints. Such a network can comprise, for example, a plurality of wireless sensor nodes that are low power devices having only a very small portable power source (such as a 1.5 volt battery having no more than, say, 1800 milliamphours of capacity and only a very limited amount of outbound payload memory (such as, for example, no more than a few bytes, such as, for example, 128 bytes of storage capacity). Such a device will typically have a relatively brief operational life before, for example, the onboard power supply becomes depleted. This operational life, however, will be even briefer if such reserves are frequently expended in favor of frequently transmitting data in order to keep space in the outbound payload memory available to receive and store new data.
In some cases, such resource constraints comprise a constraint as corresponds to system resources. For example, a severely resource-constrained wireless network may also feature severe constraints with respect to available effective bandwidth (be that available carrier frequencies, time slots, spreading codes, or the like). Such constraints can be rendered worse when seeking to accommodate a network such as a wireless sensor network that may conceivably feature hundreds or even thousands of sensors that all need access to such resources in order to convey their payloads. In such a case, it can be literally impossible to permit each and every node to transmit when and as they require in order to maintain their own platform resources (such as battery power and buffer memory) at some individually optimum level of usage.
Typical prior art approaches address and resolve such system-based resource constraints using a dynamic bandwidth allocation approach that is independent of the aforementioned hardware resource constraints. This approach in fact works well in numerous application settings and hence has prompted little in the way of fundamental change in this regard. It is the applicant's observation, however, that such an approach can lead to over-provisioning of resources in wireless nodes in a severely resource-constrained wireless network with bandwidth resources which, while lending an appearance of satisfactory operation in the sense of fostering a retrieval of node-sourced data, nevertheless tends to strap one or more platform-based resources in a manner that is ultimately detrimental to the overall operation of the system.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.

Method and apparatus to facilitate bandwidth allocation management in integral combination with memory capacity information


A system receives a search query that includes a set of search terms, determines whether at least one of the search terms corresponds to the name of a geographic area, and determines whether the geographic area corresponds to an unambiguous geographic area when at least one of the search terms corresponds to the name of the geographic area. The system performs a local search, based on one or more of the search terms, to identify documents associated with the geographic area when the geographic area corresponds to an unambiguous geographic area.

1. Field of the Invention
Implementations described herein relate generally to information retrieval and, more particularly, to the identification of a geographic reference in a search query to assist in local searching.
2. Description of Related Art
The World Wide Web ("web") contains a vast amount of information. Locating a desired portion of the information, however, can be challenging. This problem is compounded because the amount of information on the web and the number of new users inexperienced at web searching are growing rapidly.
Search engines attempt to return hyperlinks to web pages in which a user is interested. Generally, search engines base their determination of the user's interest on search terms (called a search query) entered by the user. The goal of the search engine is to provide links to high quality, relevant results (e.g., web pages) to the user based on the search query. Typically, the search engine accomplishes this by matching the terms in the search query to a corpus of pre-stored web pages. Web pages that contain the user's search terms are "hits" and are returned to the user as links.
Local search engines are search engines that attempt to return relevant web pages and/or business listings within a specific geographic area. For a local search, a user may enter a search query and specify a geographic area near which the search query is to be performed. The local search engine may return relevant results, such as relevant web pages pertaining to the geographic area or listings of businesses in the geographic area, to the user.

This patent is subject to a terminal disclaimer.

Determining unambiguous geographic references


In order to guarantee substantially trouble-free operation when manufacturing sandwich elements on a double conveyor belt installation having a downstream cross cutter and cleaning device, the cleaning device disposed on a transport carriage i) is returned to the carriage of the cross cutter to pick up the next sandwich element, is braked and is then re-accelerated to a speed higher than the production speed, ii) is, after reaching a desired distance.

The present invention relates to a process and apparatus for continuously manufacturing sandwich elements. The sandwich elements have a foam material core between two facing sheets or panels. In the process, a foam-producing reaction mixture is allowed to expand between the two facing sheets and cure to form the foam material core. A sandwich element of the desired length is then cut from the continuous sandwich thus formed by a cross cutter disposed on a carriage travelling along at the feed rate of the sandwich. After being cut away, the sandwich element is accelerated by means of a transport carriage, with a cleaning brush being passed through the gap thus formed before the sandwich element is transported away.
It is known to use a cleaning device disposed downstream of the cross cutter on a movable transport carriage to remove from the sandwich elements any cutting dust and, where the facings are metallic, any burr arising during cutting (see German patent 3,806,070). This type of construction is very expensive. In addition, problems are posed by the repeated gripping of the sandwich elements cut into lengths. Pile-ups can occur because it is not always possible to coordinate the travelling speed of the carriage of the cleaning device precisely with the feed rate of the sandwich. If a sandwich element tilts when clamped in the cleaning device, this may sometimes lead to undesirable loading of the saw blade of the cross cutter and hence to a diagonal cut.
An object of the present invention is to provide a process and an apparatus for manufacturing sandwich elements, which guarantee substantially trouble-free production even when a cleaning process is provided downstream.

Apparatus for continuously manufacturing sandwich elements


Galvanized steel sheets or a galvanized steel sheet and a sheet of another metal are welded to each other by a laser beam. An intermediate layer for suppressing evaporation of zinc is formed between the galvanized steel sheets (1, 4) or the galvanized steel sheet (1) and the sheet of another metal. A laser beam (8) is applied to the galvanized steel sheet (1) or the sheet of another metal, thereby welding the sheets with the laser beam. As a result, porosity is prevented from being formed in a weld bead (9), and the weld bead (9) has a constant width.

Welding metals with beams of high energy density (heat source), typically laser beams, is used in a wide range of metal welding applications since the welding process is clean, has a high degree of freedom, and can minimize thermal strains. Particularly, the laser beam welding process for metals finds growing use in the automobile industry or the like as a composite machining system composed of a laser oscillator and a numerically controlled apparatus or robot.
Automobiles employ a number of corrosion-resistant galvanized steel sheets as a highly durable material in their frames and other components. There is a demand for welding galvanized steel sheets with a laser beam.
FIG. 2 of the accompanying drawings shows a conventional process of welding galvanized steel sheets with a laser beam. A galvanized steel sheet 1 has plated zinc layers 2, 3 deposited on its opposite surfaces, and another galvanized steel sheet 4 also has plated zinc layers 5, 6 deposited on its opposite surfaces. When a laser beam 8 is applied to the galvanized steel sheets 1, 4 to weld them, a weld bead 10 is formed as a result of a weld pass.
Steel has a melting point of about 1545.degree. C. and a boiling point of about 2754.degree. C., whereas zinc has a melting point of 420.degree. C. and a boiling point of 903.degree. C. Because of the heat produced by the high-density energy of the applied laser beam, the zinc with a lower melting point is violently evaporated into a gas, thereby forming porosity (cavities) 11a, 11b, 11c in the weld bead 10. While only the surface porosity is shown, porosity is also formed within the weld bead 10. As a result, the weld bead 10 has irregular width dimensions, and the welded joint is rendered brittle. For the reasons described above, it has been infeasible to weld galvanized steel sheets with a laser beam.

Method of welding galvanized steel sheets with a laser beam


A process for the manufacture of anti-regurgitation infant milk is disclo wherein the milk is preheated, homogenized, and treated at ultra high temperatures and wherein a thickening agent, such as carob, guar, carrageenans, or pectins, is added prior to the homogenization step in an amount of between 0.3% and 1.0% by weight of the milk. The milk is then packaged under aseptic conditions in sterile packages.

The invention relates to a process for the manufacture of a longlife and anti-regurgitation, in particular liquid infant milk; it also relates to the milk thus obtained.
For the feeding of infants, so-called infant milk is used which, most frequently, is provided in the form of powder which is dissolved in previously heated water.
As is known, infants are frequently subject to simple, lightly abundant regurgitations which often occur after meals or during eructation phenomena. These regurgitations have no effect on the development of the child and are mainly a matter of discomfort. More rarely, real gastroesophageal refluxes exist which are linked to anatomical errors and which can have esophageal and respiratory consequences. Faced with this problem, mothers consult the child's doctor (often a pediatrician) who is generally led to prescribe proprietary products, sold in pharmacies, which contain thickening agents such as pectin, carob, carboxymethylcellulose and the like. The proprietary product in powdered form is added to the infant milk, previously heated in a water bath or in a microwave oven. Everything must be added together then allowed to stand for several minutes until thickening occurs. Although very widely used for several decades, this technique is not satisfactory because, on the one hand, the dosing of the addition is always delicate and often imprecise, and on the other hand, it is long and requires a means of heating, and finally curds often form which block the nipples. Moreover, the texture of the reconstituted product changes over time and necessitates immediate consumption of the preparation.
These thickening agents act upon contact with the acidity of the stomach by thickening the alimentary bolus, thus making it possible to avoid the refluxes by gravitational effect. The use of thickening preparations is recommended as a first choice for simple regurgitations. Drug therapies are instead reserved for recalcitrant regurgitations and especially for true refluxes. Moreover, the manufacture of longlife milk by a process called "UHT" (Ultra High Temperature) is well known. This process being well known, it is unnecessary to describe it here in detail. Essentially, this widely industrialized process consists:
in preheating a milk, standardized or otherwise, for example at 70.degree.-75.degree. C.; PA1 in homogenizing this preheated milk by throttling at high pressure (greater than 1.7.times.10.sup.7 Pascals) in order to break up the fat globules and thus prevent the cream from rising; PA1 then, in sterilizing by thermal shock at 130.degree.-145.degree. C. for two to ten seconds; PA1 finally, after cooling, in packaging under an aseptic atmosphere and in sterile packages. PA1 in preheating, then homogenizing an infant milk, PA1 then, in treating this milk at ultra high temperature (UHT), PA1 finally, in packaging under aseptic atmosphere in sterile packages, PA1 on the one hand, in pulverulent form directly into the infant milk; PA1 on the other hand, previously dissolved in distilled water, or more generally in deionised water, at room temperature, with very rapid stirring (1000 revolutions/minute and more) and is kept stirring (100 revolutions/minute and more) before being sent into the circuit; it is essential that this thickening product is maintained stirred. PA1 the carob is introduced at room temperature and with vigorous stirring (more than 1000 revolutions/minute) in pulverulent form in an amount of 0.5 to 0.8% carob flour, or in the form of an aqueous solution containing 10 to 35 grams/liter of carob; PA1 the aqueous carob solution is continuously stirred before being sent upstream to the preheating and homogenization; PA1 the thickening agent may consist of a mixture, in appropriate quantity, of guar and pectins; PA1 a solution of vitamins commonly used in the dairy industry is also added to the solution of milk to be homogenized.
However, as is known, this UHT milk is not adapted to the specific needs of infants, even after addition of thickening agents.
The invention overcomes these disadvantages. It relates to a process for the manufacture of longlife, ready-to-use infant milk which attenuates or even eliminates the risks of regurgitation.

Manufacture of anti-regurgitant milk for infants

Compagnie Europeenne de Diffusion de Produits Laitiers Cedilac SA


A connector for securing a roofing band to a roofing beam by a threaded fastener may include a circumferential flange portion, first and second recess extending within the circumferential flange portion sized to accept a roofing band, and a central portion extending within the circumferential flange portion between the first recess and the second recess, a middle area of the central portion being offset laterally from the circumferential flange portion by a distance enough to permit the roofing band to be slid through the first and second recesses so that the circumferential flange portion is located on a first side of the roofing band and the middle area of the central portion is located on a second side of the roofing band opposite the first side. A single fastener opening defined through the central portion, the fastener opening sized for receiving a threaded fastener therethrough for fastening the roofing band to a roofing beam. Related roofing assemblies and methods of construction are disclosed.

Various roofing systems have been proposed for metal frame buildings. Generally, these systems include metal beams such as rafters, struts, and purlins arranged to cover the desired building interior space. The roof may also include metal support bands and sheeting along the rafters, struts, and/or purlins. The bands and sheeting provide support for additional materials such as insulation layers that may be placed atop the sheeting. An outer roof layer is placed atop the rafters, struts, and purlins to complete the roof.
In the mid 1990's, OSHA instituted fall prevention regulations. Those regulations may in some cases impact the construction of metal frame buildings. Accordingly, protective netting, harnesses, and edge protection have been employed during such construction. Also, metal support bands underlying the sheeting and insulation have been designed so as to be able to support a person who might fall into the sheeting during construction.
In particular, title 29 C.F.R. §1926.502 requires that a roof's insulation support and fall protection system restrain and support 400 pounds dropped from at least 42 inches above the system. This standard is intended to represent potential impact of a person falling onto the structure. Energy Saver FP™ roofing systems available from Guardian Building Products incorporate structures such as bands and sheeting designed to meet such requirements. Metal roofing systems available from other sources also claim to meet such requirements. One such system requires multiple fasteners be driven through both ends of longitudinal and transverse metal support bands where attached to rafters or struts, with the fasteners being spaced at least two inches from the ends of the bands.

Connector for securing metal roofing components, metal roof assembly, and method of installing a metal roof


A data rate conversion device generates a first parameter representing a memory address position to sample and a second parameter representing a phase value of an estimation time point, records input data at a memory based on an input clock, outputs sampled continued data from the memory using the first parameter based on an output clock, and generates and outputs final data using the continued data, a plurality of filter coefficients, and the second parameter.

(a) Field of the Invention
The present invention relates to a method and device for converting a data rate of a mobile communication transmitting/receiving system.
(b) Description of the Related Art
A presently existing mobile communication transmitting/receiving system may be used with synchronization or asynchronization of a clock of a baseband modem and a clock of a radio frequency (RF) transmitting/receiving terminal. A system in which a clock of a baseband modem and a clock of an RF transmitting/receiving terminal are operated with asynchronization requests a data rate conversion device that converts from a clock rate of the baseband modem to a clock rate of the RF transmitting/receiving terminal while minimizing noise.
A general rate conversion method includes a method of converting to a rational number rate, which is M/L. In order to convert to a rational number rate, which is M/L, a method of performing down-sampling of L times, passing through a low pass filter, and performing up-sampling of M times is used. In this case, when values of M and L are embodied with a large prime number, the low pass filter should be formed with hundreds of tabs and coefficients. Accordingly, another method is a method of using a Farrow filter. In a data rate conversion device of a Farrow filter structure, when embodying hardware, hardware complexity is low, but a metastability problem occurring when using an asynchronous clock and a phase offset problem occurring due to a phase error between asynchronous clocks exist, compared with the foregoing method. Further, a problem in that a clock frequency rate error that is generated in a measurement environment should be corrected exists.

Device and method for converting data rate

Electronics and Telecommunications Research Institute


A method for scanning a weld buildup formed on a circumferential portion of a disc for a steam turbine. The method includes providing an ultrasound probe for generating at least one ultrasound beam sweep. The circumferential portion is scanned with a first beam sweep oriented in a first beam orientation to detect a first flaw type in the weld buildup. The circumferential portion is also scanned with a second beam sweep oriented in a second beam orientation to detect a second flaw type in the weld buildup. Further, the circumferential portion is scanned with a third beam sweep oriented in a third beam orientation to detect a third flaw type in the weld buildup. The method also includes rotating the disc about a disc axis during scanning of the circumferential portion and moving the first, second and third beam sweeps in a direction parallel to the disc axis during scanning.

Components of a turbine, such as turbine rotors and discs, are subjected to high stresses due to high operational speeds and temperatures. This results in the erosion of material in areas in which a turbine blade is attached to a disc (i.e. turbine blade attachment areas) and in shaft coupling areas, for example, that have complex geometries. In order to reconstruct or repair eroded areas of the turbine, a weld buildup process is used. In this process, an area to be repaired undergoes an initial machining step to prepare the area for welding. Weld material is then welded to the repair area to form a weld buildup that is subsequently heat-treated. A final machining step is then performed in order to form a desired machined shape from the weld buildup. Prior to final machining, an ultrasonic inspection is performed in order to detect flaws in the weld buildup and determine the size of the flaws.
The ultrasonic inspection is performed manually using a conventional ultrasonic straight beam probe. However, this type of arrangement can only detect flaws that are oriented in a horizontal direction (i.e. 0 degrees). Therefore, it is desirable to provide improved flaw detection techniques in a turbine component.

Method for ultrasound scanning of a weld buildup


A screw press for drying elastomeric polymers and the like having a cylindrical barrel and intermixed, substantially solid and apertured, discontinuous screw flights for more quickly initiating pressure and temperature increase of polymer in the barrel without increasing the back-up restriction and final pressure at the discharge end of the barrel.

In the synthetic rubber industry, extensive use has been made of screw presses with intermittent thread flights in both the dewatering and final drying stages of manufacture. Zies U.S. Pat. No. 3,222,797 discloses such a drying press or "expander" in which the dewatered polymer fed to the press barrel inlet is initially propelled forwardly by a continuous flight unit of several turns or wraps, then advanced through a series of separate flights, and, finally, is ejected through a perforated die plate exit restriction. Rows of "breaker" bolts project radially into the cylindrical barrel between the individual thread flights to increase the resistance to rotation of the feed stock plugs as they are advanced through the casing by rotation of the feed worm. The die head restriction is variable so that the polymer will be compacted throughout a substantial portion of the barrel by the action of the pitched flights. Once the polymer is compacted and "worked," i.e., agitated and kneaded by screw action, heat is developed by friction and hysteresis effects and under the influence of external heating means. The temperature and pressure of the polymer and contained water rise during the process. As the polymer exits through the discharge dies, the pressure is abruptly reduced to atmospheric and the superheated water is released as steam as the polymer expands. This is how drying is accomplished.
Since there are a variety of polymer types with different properties, variable temperature and pressure requirements necessary for drying are usually achieved by proper selection of the size, shape, and number of discharge die openings.
When maximum throughput rates are desired, the die considerations must be adjusted to cause sufficient restriction and back pressure to produce compacting of the rubber through most of the length of the barrel, so that the polymer will receive maximum work input and heating. This often results in extreme pressures at the die head, e.g., as much as 1500 p.s.i.g., and extreme velocities of polymer through the dies. This can produce intolerable conditions at the expander exit because the violent explosions and high velocities produce a very fine product which sticks to the equipment and conveyors, is drawn into the ventilation system, and conveys poorly.
Another disadvantage in the described arrangement is in the tendency of the highly pressured and heated polymer to produce non-uniform crumb with stranded, dense product from some holes and fragmented, blowing fines from other holes.
In the above described prior art drying practice, all thread flights of the feed worm have a drive shaft wrap of approximately 95%. However, Zies U.S. Pat. No. 3,034,424 discloses a feed screw press for removing oil or the like from organic materials, while preventing damaging pressuring and heating of the liquid. Separate flights of the feed screw are variously shortened and relatively positioned to produce tortuous relief passages for returning excessively pressured product to the barrel inlet, to prevent excessive pressure and temperature build-up in the barrel.

Screw press for drying elastomeric polymers


The present invention describes a multi-stage decoder and method of decoding utilizing a pseudo NAND or pseudo AND gate in one of the stages. This invention presents a decoder comprising a first stage circuit having two or more first inputs which generates one or more first outputs; and a second stage circuit having at least one second input and at least one second output, wherein the one or more first outputs are the same as the at least one second input, wherein at least one of the group consisting of the first stage circuit and the second stage circuit includes either a pseudo AND gate or a pseudo NAND gate. This invention presents a method of decoding, comprising the steps of generating a signal responsive to two or more address bits and enabling a decoder by the generated signal.

The present invention generally relates to the field of decoders, and particularly to a decoder with a single critical path for a very high speed synchronous memory.
A series of AND gates or a series of NOR gates, which are the complement of AND gates, are used for decoding of logical input signals, to address memory matrices. As an example, for each group of AND circuits, hereinafter called AND blocks or conventional decoders, there is provided a plurality of logical input signals, depending on the operation to be performed, and there is one output decoded line for each conventional decoder. Associated with each conventional decoder is also a clock pulse input to provide the necessary switching logic for the proper operation of the devices. The conventional decoder blocks are commonly used in the MOSFET large scale integration technology to provide addressing or accessing signals for storage memory arrays. The number of address lines for the memory has been limited by the number of decoded output lines available from the conventional decoders for a particular chip size wherein the spacing between the decoded output lines is referred to as xe2x80x9cpitchxe2x80x9d. Consequently, using MOSFET technology ground rules suitable for maximum density memory fabrication put a restriction on the minimum pitch and minimum array dimensions achievable with these ground rules using conventional decoders, the limitation being the minimum pitch dimension of the conventional decoders.
When a word line decodes an address, the decoder is usually drawn as a NAND gate. This NAND gate takes a large layout area in the tight row decoder pitch. To drive these arrayed NAND gates, the pre-decoder output driver is big.
If a dynamic NAND gate is used for a decoder, a pre-charger signal is required to disable the word line and this pre-charger driver size will be big. A big driver size makes a big load on the previous stage and it makes lower performance also. And it may cause skew or race problem of address and control signal.
An object of the present invention is to provide word line decoder and driver circuits for high density semiconductor memories.
Accordingly, the present invention is directed to a decoder scheme in which one row address (usually the lowest significant bit address) is controlled to be a critical path by address set up control and word line disable timing. Pre-decoded address with the above address bit will control the PMOS transistors of the pseudo AND or pseudo NAND gate.
This invention is smaller and faster than a full AND or full NAND implementation and simpler than a dynamic AND or dynamic NAND implementation as it relates to the control signal derivation.
This invention presents a decoder comprising a first stage circuit having two or more first inputs which generates one or more first outputs; and a second stage circuit having at least one second input and at least one second output, wherein the one or more first outputs supplies a signal to the at least one second input, wherein at least one of the group consisting of the first stage circuit and the second stage circuit includes either a pseudo AND gate or a pseudo NAND gate.
This invention presents a method of decoding, comprising the steps of generating a signal responsive to two or more address bits and enabling a decoder by the generated signal.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.

Address decoder with pseudo and or pseudo nand gate


A fuel cell system is provided including a fuel cell stack having a first end and second end. The fuel cell stack includes at least one fuel cell having a membrane-electrode assembly disposed between adjacent gas diffusion layers. The fuel cell system further includes a compression retention system having a plurality of compliant straps adapted to apply a compressive force to the fuel cell stack. The plurality of compliant straps are further adapted to accommodate an expansion of the fuel cell stack during an operation thereof and maintain the compressive force within a desired range.

Fuel cells have been proposed as a clean, efficient and environmentally responsible power source for electric vehicles and various other applications. One example of a fuel cell is the Proton Exchange Membrane (PEM) fuel cell. The PEM fuel cell includes a membrane-electrode-assembly (MEA) that generally comprises a thin, solid polymer membrane-electrolyte having an electrode including a catalyst on both faces of the membrane-electrolyte.
The MEA generally comprises porous conductive materials, also known as gas diffusion media (GDM), which distribute reactant gases to the anode and cathode electrode layers. Fuel, such as hydrogen gas, is introduced at the anode where it reacts electrochemically in the presence of the catalyst to produce electrons and protons. The electrons are conducted from the anode to the cathode through an electrical circuit disposed therebetween. Simultaneously, the protons pass through the electrolyte to the cathode where an oxidant, such as oxygen or air, reacts electrochemically in the presence of the electrolyte and catalyst to produce oxygen anions. The oxygen anions react with the protons to form water as a reaction product.
The MEA is generally interposed between a pair of electrically conductive contact elements or bipolar plates to complete a single PEM fuel cell. In typical operation, the MEA is known to expand and contract with changes in humidity and temperature. Compression retention systems are typically designed in a manner effective to offset the strains produced by membrane swelling that can occur with membrane expansion and compressive stress relaxation in the fuel cell stack. In conventional fuel cell stacks, for example, the MEA is known to expand by up to about 50% of its original thickness in operation.
Compression retention systems act to minimize an over-compression of the fuel cell stack and are designed to maintain a desired contact pressure between bipolar plates, gas diffusion media, and catalyst layers. A limited amount of compression set of the GDM occurs under typical operational loads of the fuel cell stack. However, when excessive compression loads are applied to the GDM, the force can physically degrade the GDM by fracturing carbon fibers or breaking up binders that bind the carbon fibers together to an undesirable extent. Therefore, it is generally desirable for an appropriate compression load to be maintained and provide a desired electrical resistance, but not to exceed the desired range during operation of the fuel cell stack.
It is stated in U.S. Pat. No. 5,484,666 to Gibb et al. that conventional compression systems have consisted of tie rods extending through and between endplate assemblies and secured with fastening nuts. Springs threaded on the tie rods and interposed between the fastening nuts and the endplates have been used to apply resilient compressive force to fuel cell stacks in the stacking direction. Fuel cell side plates having controlled tensile compliance are also reported in U.S. Pat. Appl. Pub. No. 2006/0040166 to Budinski et al. It is stated in Budinski et al that the compression forces on a fuel cell stack can be controlled by incorporating at least one spring element into a side plate.
In U.S. Pat. No. 5,789,091, Wozniczka et al. further reports a mechanism for securing a fuel cell stack in an assembled and compressed state which includes at least one compression band that circumscribes end unit assemblies and interposed fuel cells in the fuel cell stack. Murphy et al. in U.S. Pat. No. 6,040,072 also reports an apparatus for securing an electrochemical cell stack that includes a banding member.
Assignee's co-pending U.S. patent application Ser. No. 11/638,283, hereby incorporated herein by reference in its entirety, describes a compression retention system including at least one generally planar strap forming at least one bend, the at least one strip extending from a first end to a second end unit of the fuel cell stack. Also, assignee's co-pending U.S. patent application Ser. No. 11/591,377, hereby incorporated herein by reference in its entirety, describes a compression retention system composed of at least one tie rod extending from an upper end unit to a lower end unit. The tie rod is disposed outside of the fuel cell stack and fastened to the end units by brackets secured to the end units. A spring is interposed between at least one of the fastener and the end units.
There is a continuing need for a compression retention system for electrochemical fuel cells that optimizes a mass, volume and thermal efficiency of the fuel cell system, provides substantially uniform compression during fuel cell stack operation and with a variety of stack sizes, and militates against a degradation of the gas diffusion media in the fuel cell stack.

Fuel cell compression retention system using compliant strapping


A phase-locked loop including an oscillator, controlled by a control signal generated by a comparison circuit comparing a reference frequency and the oscillator frequency and filtered by an integrator low-pass filter; a control and adjustment circuit for, with a predetermined frequency smaller than the reference frequency, taking into account the value of the filtered controlled signal and, if this value is out of a range of predetermined values, adjusting the operating range of the oscillator; and an inhibition circuit for deactivating the comparison circuit for a predetermined duration before taking into account the value of the filtered control signal.

1. Field of the Invention
The present invention relates to phase-locked loops, and in particular to a phase-locked loop made in an integrated circuit.
2. Discussion of the Related Art
FIG. 1 schematically shows a phase-locked loop conventionally used in frequency synthesis. The phase-locked loop includes a voltage-controlled oscillator (VCO) 2 generating a periodic output signal of frequency Fout to be synchronized on a reference frequency Fref. A comparison circuit 4 compares a signal with reference frequency Fref and with a frequency signal Fdiv equal to a division of frequency Fout by a predetermined factor N. Comparison circuit 4 provides a control signal to an integrator low-pass filter 6. Filter 6 provides a voltage Vcom for controlling oscillator 2. Frequency Fout varies between minimum and maximum frequencies, in an operating range characteristic of the oscillator, when voltage Vcom varies between minimum and maximum values.
The phase-locked loop is made in an integrated circuit, except for filter 6, as will be seen hereafter. The characteristics of the integrated components may vary along with the manufacturing process. In particular, the operating range of oscillator 2 may vary along with the manufacturing process, which may cause a malfunction of the phase-locked loop. To solve this problem, the operating range of oscillator 2 is adjustable by an adjustment signal FA, generated by a control and adjustment circuit 8. Circuit 8 is provided to control whether the oscillator is in a desired operating range or not. For this purpose, circuit 8 ensures that voltage Vcom of oscillator 2 does not have a value greater than a high threshold value VH, or that it does not have a value smaller than a low threshold value VL. If voltage Vcom is greater than value VH, circuit 8 generates an adjustment signal FA adapted to adjusting the operating range of oscillator 2 upwards. If Vcom is smaller than value VL, circuit 8 generates an adjustment signal FA adapted to adjusting the operating range of oscillator 2 downwards. The taking into account of the value of voltage Vcom by circuit 8 is periodically activated by a clock signal CKaj. Signal CKaj is generated by a frequency divider 9 based on reference frequency Fref.
FIG. 2 schematically shows an implementation of oscillator 2 and adjustment and control circuit 8. Oscillator 2 includes a negative-resistance amplifier 10, the output of which is the oscillator output. The input of amplifier 10 is connected to a first terminal of a capacitor C. The second terminal of capacitor C is connected to the oscillator input via a resistor R. The cathode of a varicap diode Dv is connected to the second terminal of capacitor C. The anode of diode Dv is connected to a ground GND. An inductance L and a variable capacitor Cv are connected in parallel between the input of amplifier 10 and the ground. The capacitance of variable capacitor Cv is controlled by signal FA. As an example (not shown), adjustment signal FA may be a digital signal and capacitor Cv may be formed of a capacitor of predetermined value connectable in parallel with several capacitors by switches, each controlled by one bit of adjustment signal FA. Oscillator 2 has the following operating frequency:Fout=½π[L(Cv+Cdv)]1/2,
where Cdv is the dynamic capacitance of varicap diode Dv, which varies according to control voltage Vcom. The adjusting of the capacitance of capacitor Cv by adjustment signal FA enables adjusting the oscillator operating range. Control and adjustment circuit 8 includes comparators 12 and 14 enabling comparing voltage Vcom with values VH and VL. Comparators 12 and 14 control a coding block 16. Coding block 16 controls via an adder the incrementation or the decrementation of adjustment signal FA, stored in a D flip-flop 18 clocked by clock signal CKaj. The value of voltage Vcom is thus taken into account by circuit 8 at each rising edge of signal CKaj, and causes, if necessary, an immediate adjustment of the operating range.
FIG. 3 illustrates the variations of frequency Fout of the oscillator according to voltage Vcom for different values of adjustment signal FA. For simplicity, the capacitance of variable capacitor Cv is assumed to only be able to take two values, and digital adjustment signal FA is assumed to only take values 0 or 1. In practice, adjustment signal FA may be comprised of several bits and the capacitance of capacitor Cv may take a great number of values. Voltage Vcom varies between a minimum value Vmin and a maximum value Vmax. In the illustrated example, the capacitance of capacitor Cv is maximum when adjustment signal FA is 0. The oscillator then is in a low frequency range. Frequency Fout then linearly varies between a low frequency FL0 when voltage Vcom has a value Vmin and a high frequency FH0 when voltage Vcom has a value Vmax. When adjustment signal FA is 1, the oscillator is in a high frequency range. Frequency Fout then linearly varies between a low frequency FL1 when voltage Vcom has a value Vmin, and a high frequency FH1 when voltage Vcom has a value Vmax. Threshold values VH and VL, which define the voltage range out of which circuit 8 controls an adjustment of the oscillator operating range, are respectively chosen to be slightly smaller than value Vmax and slightly greater than value Vmin. For simplicity, it is considered hereafter that values Vmin and Vmax are substantially equal respectively to ground GND and to value Vdd of the circuit supply voltage.
When the value of voltage Vcom is taken into account by circuit 8, if adjustment signal FA is 0 and if voltage Vcom has a value greater than VH, circuit 8 brings adjustment signal FA from 0 to 1. Similarly, if adjustment signal FA is 1 and if the value of voltage Vcom is smaller than value VL, circuit 8 brings adjustment signal FA from 1 to 0. The operating ranges of the oscillator partially overlap, and oscillator 2 and control and adjustment circuit 8 are chosen so that the median frequency of the upper range substantially corresponds to the high frequency of the lower range. Similarly, the median frequency of the lower range substantially corresponds to the low frequency of the upper range.
FIG. 4 illustrates the variation of frequency Fout of the oscillator according to control voltage Vcom and the variation of voltage Vcom along time in the previously-described phase-locked loop.
It is assumed that, initially, the phase-locked loop is stabilized at a frequency F1 belonging to the lower operating range of the oscillator. Voltage Vcom then has a value V1.
At a time t0, the equilibrium of the phase-locked loop is modified to control a change in output frequency Fout from frequency F1 to a higher frequency F2. The equilibrium of the phase-locked loop is for example modified by increasing the division ratio N determining variable frequency Fdiv. Comparison circuit 4 detects a difference between reference frequency Fref and variable frequency Fdiv, and controls an increase of voltage Vcom. Voltage Vcom is brought from its value V1 to a value V2 corresponding to frequency F2 in the lower operating range of the oscillator. Voltage Vcom varies from value V1 to value V2 in a damped sinusoid. It is assumed, in the illustrated example, that value V2 is greater than threshold value VH.
At a time t1, the value of voltage Vcom is taken into account by control and adjustment circuit 8. Vcom being greater than VH, circuit 8 determines that the oscillator no longer is in the desired operating range, and it brings the oscillator into its upper operating range. Voltage Vcom still is at value V2, and the oscillator then oscillates at a frequency F3 close to maximum frequency FH1 of the oscillator in the upper operating range. The oscillator frequency is then greater than the desired frequency F2. The phase-locked loop then tends to reduce the oscillator frequency. To achieve this, the phase-locked loop brings voltage Vcom from value V2 to a desired value V4, corresponding to frequency F2 in the upper operating range of the oscillator, in a damped sinusoid (shown in dotted lines). Voltage Vcom varies from value V2 to the desired value V4 in a convergence duration Δt, taking intermediary values which may be located out of voltage range VL-VH, although the desired value V4 is in this voltage range. If control and adjustment circuit 8 took into account the value of voltage Vcom at a time when this voltage is outside of range VL-VH, it would, wrongly, determine that the oscillator is in a poorly adapted frequency range. Convergence duration Δt depends on values V2 and V4 and on the characteristics of the phase-locked loop. Conventionally, to avoid for circuit 8 to take into account the intermediary values of voltage Vcom, the period with which the value of voltage Vcom is taken into account is chosen to be greater than the maximum convergence duration Δt of voltage Vcom. In some cases, however, in particular for some embodiments of comparison circuit 4 and of filter 6 of FIG. 1, the convergence duration Δt during which voltage Vcom is likely to take intermediary values located outside voltage range VL-VH may be particularly lengthened.
FIG. 5 illustrates an example of embodiment of a comparison circuit 4 and of an integrator low-pass filter 6 likely to lengthen convergence duration Δt.
Comparison circuit 4 includes a phase/frequency comparator 20 comprised of two D flip-flops respectively clocked at frequencies Fref and Fdiv, having their input terminals connected to a logic level 1. The output terminals of the D flip-flops respectively generate signals UP and DWN. The D flip-flops are reset by a NAND combination of signals UP and DWN. An output terminal A of comparison circuit 4 is connected via a switch 22 to a source 24 of a positive constant current +I. Switch 22 is respectively on or off when signal UP is at 1 or 0. Output terminal A is also connected via a switch 26 to a source 28 of a negative constant current −I. Switch 26 is respectively on or off when signal DWN is equal to 1 or to 0.
Filter 6 includes a capacitor C1 of high value connected in series with a resistor R1 between terminal A and the ground. A capacitor C2 of low value as compared to C1 is also connected between terminal A and the ground. Capacitor C1 plays the function of an integrator of the current provided by circuit 4. Capacitor C2 eliminates the high-frequency components of the current provided by circuit 4.
When a small difference exists between frequencies Fref and Fdiv, comparison circuit 4 provides short current pulses to filter 6. If the current pulses are positive, capacitors C1 and C2 charge at constant current during each pulse. Capacitor C1 charges through resistor R1, while capacitor C2 charges through a negligible parasitic resistance. Between two consecutive pulses, capacitor C2 discharges into capacitor C1 through resistor R1. Similarly, if the current pulses are negative, capacitors C1 and C2 discharge at constant current during each pulse and capacitor C2 charges from capacitor C1 through resistor R1 between two consecutive pulses. The mean value of control voltage Vcom then depends on the difference between reference frequency Fref and variable frequency Fdiv provided by the oscillator, and the phase-locked loop operates normally.
However, when frequencies Fref and Fdiv are very different, comparison circuit 4 provides long current pulses to filter 6. At the beginning of a long current pulse, capacitors C1 and C2 charge (respectively, discharge) at constant current. Capacitor C2 charges (respectively, discharges) rapidly. From the time when capacitor C2 is charged (respectively, discharged), to the end of the current pulse, voltage Vcom is maintained at value Vdd (respectively, GND). Considering that no current is absorbed by oscillator 2, all the current provided by comparison circuit 4 then flows through resistor R1. The voltage drop in resistor R1, of high value, then is on the order of Vdd and capacitor C1 is charged (respectively, discharged) with a reduced current. Further, the duration separating the consecutive current pulses may be too short for capacitor C2 to have time to completely discharge (respectively, to completely charge) into capacitor C1 between two consecutive current pulses. Voltage Vcom is then maintained at a value close to Vdd (respectively, to GND).
FIG. 4 illustrates (in full line) the variation of frequency Fout according to voltage Vcom and the variation of voltage Vcom along time in a phase-locked loop comprised of comparison circuit 4 and of filter 6 of FIG. 5. Until time t1, voltage Vcom varies as previously described. It is assumed that at time t1, the difference between frequencies F3 and F2 is sufficiently large for voltage Vcom to be rapidly brought to a value close to ground GND and smaller than value VL. The oscillator then oscillates at a frequency close to minimum frequency FL1 of the upper operating range. The saturation of comparison filter 4 and of filter 6 is such that voltage Vcom keeps a value close to GND until a time t2 when the value of voltage Vcom is taken into account by circuit 8.
At time t2, circuit 8 erroneously determines that the oscillator no longer is in the desired operating range and it brings the oscillator into its lower operating range. Voltage Vcom still is grounded and the oscillator then oscillates at a frequency close to minimum frequency FL0 of the lower operating range. This frequency being much lower than frequency F2, voltage Vcom is rapidly brought to a value close to value Vdd and greater than value VH. Comparison circuit 4 and filter 6 are saturated in such a way that voltage Vcom is maintained at value Vdd until a time t3 at which voltage Vcom is taken into account again by circuit 8.
At time t3, circuit 8 brings the oscillator back into its upper operating range. The phase locked-loop behaves from time t3 as from time t1, and it cannot stabilize.
As seen previously, a solution to prevent such an oscillation of the phase-locked loop is to decrease the frequency with which the value of voltage Vcom is taken into account by control and adjustment circuit 8. The value of voltage Vcom is then always taken into account after the phase-locked loop is stabilized. However, such a solution reduces the frequency with which the oscillator frequency range can be adjusted, even when comparison circuit 4 and filter 6 are not saturated, which is not desirable.

Phase-locked loop with high frequency adjustment of the operating range of the oscillator


In a spectroscopy module 1, a light passing hole 50 through which a light L1 advancing to a spectroscopic portion 4 passes is formed in a light detecting element 5. Therefore, it is possible to prevent the relative positional relationship between the light passing hole 50 and a light detecting portion 5a of the light detecting element 5 from deviating. Moreover, the light detecting element 5 is bonded to a front plane 2a of a substrate 2 with an optical resin adhesive 63. Thus, it is possible to reduce a stress generated onto the light detecting element 5 due to a thermal expansion difference between the light detecting element 5 and the substrate 2. Additionally, on the light detecting element 5, a first pool portion 101 is formed so as to be located at least between the light detecting portion 5a and the light passing hole 50 when viewed from a direction substantially perpendicular to the front plane 2a. Thus, when the light detecting element 5 is attached to the substrate 2 via the optical resin adhesive 63, the optical resin adhesive 63 is pooled to remain at the first pool portion 101. Thus, the optical resin adhesive 63 is prevented from penetrating into the light passing hole 50.

1. Field of the Invention
The present invention relates to a spectroscopy module for dispersing light to detect the light.
2. Related Background of the Invention
There is known such a conventional spectroscopy module described in, for example, Japanese Published Unexamined Patent Application No. H04-294223, Japanese Published Unexamined Patent Application No. 2004-354176, and Japanese Published Unexamined Patent Application No. 2003-243444. Japanese Published Unexamined Patent Application No. H04-294223 has described a spectroscopy module which is provided with a supporting body through which light is allowed to transmit, an incident slit portion through which light is made incident into the supporting body, a concave diffraction grating that disperses the light made incident into the supporting body to reflect the light, and a diode that detects the lights dispersed and reflected by the concave diffraction grating.


A system for providing media content in a vehicle includes a content component, a noise component, and a closed captioning component. The content component is configured to receive content from a content provider, wherein the content is configured for rendering by the media system of a vehicle. The noise component is configured to determine a noise level within a cabin of the vehicle. The closed captioning component is configured to, in response to determining that the noise level exceeds a threshold, trigger display of closed captioning for the content.

Automobiles provide a significant portion of transportation for commercial, government, and private entities. Autonomous vehicles and driving assistance systems are currently being developed and deployed to provide safety features, reduce an amount of user input required, or even eliminate user involvement entirely. For example, some driving assistance systems may drive a vehicle from one location to another without user input or may provide assistance to a user as a human drives. These systems often require knowledge of an environment, such as current driving conditions obtained through sensors or wireless network communication, and/or such as location or roadway information available from locally or remotely stored map data.

Systems, methods, and devices for rendering in-vehicle media content based on vehicle sensor data


A HVAC system (10) employs a gas valve (20) to supply gas for combustion within a heating portion (12) of the system. An exhaust (22) removes combustion products using a motor (28) driven exhaust fan (24). An apparatus (34) controls combustion and uses a sensor (36) for sensing the rotational speed of a motor shaft (26). A switch (T1) is responsive to sensed motor speed to open and close the valve, the valve being opened only if the motor is operating within a predetermined speed range. A first speed discriminator (48A) enables of the switch to open the valve when the motor speed exceeds a first predetermined value. A second speed discriminator (48B) disables the switch to close the valve when motor speed exceeds a second and higher predetermined speed which is indicative of a blocked exhaust, or a fan blade is loose. This latter action insures that a build-up of potentially dangerous exhaust gases cannot occur.

This invention relates to heating, ventilation, air conditioning (HVAC) systems and, more particularly, to apparatus for controlling operation of the portion of a system as a function of whether or not an adequate draft is induced in the exhaust so combustion products are discharged from the system.
In conventional HVAC systems, gas is supplied to a furnace portion of the system through a switch controlled valve. The gas is combusted to heat air which is then circulated through the system. The products of combustion, carbon monoxide, etc., are exhausted through a flue or exhaust duct. For this purpose, a draft is induced in the flue or duct by a motor driven fan. The resultant air flow draws off the combustion products from the chamber to the flue. Because the exhaust gases are potentially dangerous, it is important to know if they are, in fact, being exhausted.
There are a number of reasons why they may not be. Among these are a fan motor which is not functioning, a blower fan which is loose, a blocked exhaust flue or duct, etc. Operationally, the HVAC system is controlled so that the gas valve is opened only when a sufficient flow of air is induced in the exhaust. If it is ascertained that combustion gases cannot be properly exhausted, for any of the above reasons, then the valve is not opened.
Various techniques exist for determining if a sufficient air flow is being produced. For example, it is known to monitor the rotational speed of an exhaust motor shaft on which an exhaust fan is installed to insure that the motor is rotating above some predetermined speed. If it is, the gas valve can be opened; otherwise, not. This monitoring device is typically a centrifugal switch which closes when the motor speed exceeds some minimum value, and opens when the speed drops below that level. Such devices have a number of drawbacks. While do they monitor shaft speed, they cannot determine if a fan blade is loose and therefore not able to move a volume of gas. They cannot tell if there is flue blockage. It is possible to employ other devices to monitor for these potential problems. Thus, a pressure sensor installed in the flue could sense a blockage condition. Or, air flow sensors could be used to ascertain flow levels toward the exhaust. However, employing more sensors has an impact in a number of areas. More parts have to be installed, calibrated and adjusted, increasing set-up time. More parts are involved increasing inventory costs. With more parts, the reliability of the system decreases and a certain amount of redundancy may have to be built into the system so that its operating life is maintained. Again, this adds to system cost.
It would be advantageous to have available a single sensor to monitor all these different potential areas of failure; especially, a sensing mechanism whose cost is comparable to that of existing low cost sensors and substantially less than that of other sensors which would otherwise be used.


An edge image extraction light modulator forms an edge portion image corresponding to a boundary between two optically equalized portions of a liquid crystal layer. Each portion has a different bistable state and an edge portion optically distinct from the two optically equalized portions. An optical image is written onto the light valve while applying a voltage between two transparent electrode layers of the light valve to effect switching between a first stable optical axis and a second stable optical axis. The light valve is illuminated and the edge portion of the written image is read. A first and a second polarizer are in crossed-Nicols position so that the two optically equalized portions comprise a portion having the written image except for the edge portion thereof and a non-written portion. The edge portion is not optically equal to the two optically equal portions and can thus be detected. A method of driving the edge image extraction light modulator includes writing an optical image onto the light valve by irradiating a photoconductive layer with light. A first pulse voltage is applied to erase and reset the light valve, and a second pulse voltage is applied, having a polarity opposite that of the first pulse voltage, to generate carriers diffusing in the photoconductive film to impart an electric field to the liquid crystal layer and form an enlarged image of the optical image in the light valve. A third pulse voltage, having the same polarity as that of the first pulse voltage, erases a part of the enlarged image except for an edge portion thereof to form an edge enhanced image in the light valve.

The present invention relates to a optically writeable spatial light modulator of an liquid crystal type and relates to a driving method thereof, which may be utilized in an image processing device and an optical information processing device. More specially, the liquid crystal type composes a ferroelectric liquid crystal type having optical bistability.
Conventionally, the spatial light modulator of the ferroelectric liquid crystal type is utilized as an optical device for modulating an intensity of inputted image information on real time basis to output the modulated result. Generally, the outputted image is a binarized form of the inputted image. Further, the inventors have disclosed a method of driving the above noted optical modulator to produce an output image having a continuous gradation in Japanese Patent Application No. 239594/1990.
However, according to the conventional driving methods, there is produced only an output image associated to an intensity distribution of an input image. There could not be directly produced an output image in an edge enhanced form or an edge extracted form, which would be useful in optical information processing technology.

Liquid crystal spatial light modulator for edge detection employing diffusion in the photoconductive layer to enlarge image


A telephone system for providing communications between mobile radiotelephones, portable radiotelephones and landline telephones includes a land-line telephone system including a land-line switching network for providing communication paths for land-line telephones and a mobile radiotelephone system for providing communications paths for mobile and portable radiotelephones. The mobile radiotelephone system includes a digital switching network, base stations, and PCM analog-to-digital (A/D) and digital-to-analog (D/A) converters interposed between the base stations and the digital switching network and between the land-line switching network and the digital switching network. Analog ports are interfaced by the PCM A/D and D/A converters to incoming and outgoing serial bit streams coded according to pulse-code-modulation (PCM) techniques standardized for telecommunications systems by the International Telegraph and Telephone Consultative Committee (CCITT).. The digital switching network receives the incoming serial PCM bit streams and provides the outgoing serial PCM bit streams so that telephone calls are automatically routed between the calling and called parties in the telephone system. Supervisory signalling is detected from the incoming serial PCM bit streams and processed by a signal processing computer to determine an ordering of time slots for the PCM channels for controlling the interchange of PCM channels from the incoming serial PCM bit streams to the outgoing serial PCM bit streams. Supervisory signalling for outgoing PCM channels corresponding to the incoming supervisory signalling from incoming PCM channels is adapted to to a pre-established format recognized by the corresponding outgoing PCM channels and multiplexed into the respective outgoing serial PCM bit streams.

1. Field of the Invention
This invention relates to a method of and an apparatus for a telephone system for radiotelephone communications, and more particularly to an improved telephone system for radiotelephone communications utilizing pulse-code-modulation (PCM) techniques.
2. Description of the Prior Art
Prior art telephone systems for radiotelephone communications have included a single base station for covering a large service area, for example, an entire city, which is in turn connected to a telephone central office. The base station typically had a plurality of duplexed radio channels for providing radiotelephone service to a somewhat limited number of mobile radiotelephones in a densely populated city. Expansion of service to a large number of radiotelephones could only be accomplished by adding more radio channels to such radiotelephone systems. However, the number of radio channels for use in such radiotelephone systems is limited both by governmental regulation and the unavailability of other radio channels. As a result, more mobile radiotelephones had to be added to the existing system, thereby creating congestion on the system's limited number of radio channels.
The problems of the foregoing prior art telephone systems have been solved to some degree by improved radiotelephone systems utilizing a plurality of base stations located in geographical cells. The base stations are operated at relatively low power such that the radio channels assigned to a first base station can be reused by a second base station that is sufficiently distant from the first base station to prevent radio frequency interference. By reusing the available radio channels throughout a large geographical area, a greater number of mobile radiotelephones can be accommodated by such radiotelephone systems.
However, in order to control the operation of such radiotelephone systems, a more complex switching network is required that can handle a large number of remotely located base stations and a large number of mobile radiotelephones including both vehicular and hand-held or portable radiotelephones. In addition, it is highly desirable that the switching network is designed to be capable of providing to the mobile radiotelephones all the telephone service features which are presently available to land-line telephones. For example, these telephone service features include services such as repertory dialing, automatic call forwarding, and automatic conference calling. None of the prior art radiotelephone systems is capable of providing any of these features. Thus, prior art radiotelephone systems cannot accommodate a relatively large number of mobile radiotelephones nor provide the foregoing and similar automatic telephone service features to mobile radiotelephones.
For the foregoing and other shortcomings and problems, there exists a need for an improved telephone system for radiotelephone communications that is capable of handling a large number of base stations and mobile radiotelephones and capable of providing many different standard and unique service features to the mobile radiotelephones.


A system for preventing CRT phosphor burn in a multiple CRT projection type television system is disclosed. The absence of an electron beam deflection signal in the deflection yoke of a CRT is detected and used to provide a signal to CRT shutdown circuitry by means of an unbalanced transformer approach in which the various deflection yoke signals energize a plurality of primary transformer coils with a shutdown signal provided by the transformer secondary when a primary coil flux unbalance occurs.

This invention relates generally to multiple CRT projection type television systems, and particularly relates to a system for preventing CRT phosphor burn in a multiple CRT projection type television system.
A common type of projection television system includes three cathode ray tubes disposed side by side relative to one another each emitting a light beam of one of the three different primary colors, red, green and blue, onto a generally planar projection screen through a lens assembly. The three different color light beams form a proper colored picture when they are projected onto the projection screen in such a manner that images of different color are superimposed upon one another without any displacement.
The three cathode ray tube (CRT) projection color television receiver approach as well as other projection television system approaches have suffered from inherent limitations in the brightness of the reproduced image on the projection screen. These limitations have necessitated a darkened viewing environment for optimum projection television receiver viewing. Other equally undesirable conditions from the viewer's standpoint have been caused by limitations in video display brightness and contrast in a projection television receiver. These limitations result from various characteristics of the projection television environment such as light losses in the image projection lens system, absorption and dispersion of the light energy containing image information incident upon the projection screen, reflection losses if a mirror system is used, and the large size of the projection screen relative to the total surface area of the three CRT's employed in the projection television system. To compensate for these inherent projection television system limitations, substantial effort has been expended to enhance the images produced by the individual CRT's.
The principle elements in the tubes are an electron gun, a target coated with a phosphor upon a surface directly facing the impinging electron beam, various mirror and/or lens combinations to achieve the desired optical effects, and a transparent faceplate through which the image is projected upon a screen external to the CRT's envelope. The most common approach to increasing image intensity, or brightness, is to increase the inter-electrode voltages which accelerate the electrons toward the phosphor-coated faceplate. This has resulted in an increased danger of permanently damaging the CRT's screen by means of a continuous beam of undeflected, energetic electrons impinging on the same spot, or small area, when deflection voltages are removed. During normal operation the electron beam is swept vertically and horizontally across the CRT faceplate. Should a vertical or horizontal deflection yoke malfunction or be deprived of appropriate deflection signals during operation, a permanent mark will be "burned" on the phosphor coating of the CRT's faceplate in the form of a spot or a horizontal or vertical line. This is not a new problem brought on by the advent of projection television systems, for there is much in the prior art addressing this problem in conventional television receivers, but it is only of recent that this problem has been dealt with in the context of a projection television system environment.
One approach to protecting the projection television system's CRT faceplate is disclosed in Quasar Electronics Company Service Manual for projection television chassis AMVDTS-800 published in 1978 by Matsushita Electric Corporation of America. FIG. 1 shows the horizontal deflection yoke open circiut detector system described in a detailed schematic in the referenced Quasar Service Manual. Under normal conditions with current flowing through green 13, blue 15 and red 17 deflection yokes, the magnetic effects in transformer 11 and 19 caused by the current flowing through coils L2 and L3 in each of the transformers cancels out. Thus, under normal operating conditions no current is induced in windings L1 of transformers 11 and 19. With no composite pulse induced in the L1 windings, diode 21 which is connected to them in series detects no voltage. However, during abnormal operation of any of the three deflection yokes, an output voltage is provided to diode 21 in the following manner. If blue deflection yoke 15 ceases to induce a positive pulse in the L3 winding of transformer 11, the L1 winding in that transformer becomes unbalanced because of the presence of only the positive pulse induced by L2. Since transformer 19 does not include a winding from blue deflection yoke 15, L1 in transformer 19 remains balanced. Diode 21 detects and rectifies only the positive pulse form from the L1 winding to transformer 11 and this output is used to control beam current shutoff circuitry. Failure of either the red or green deflection yokes 17 or 13, respectively, will produce the same unbalanced flux condition in transformers 11 and 19 producing a resultant output pulse used to drive CRT shutdown circuitry. Transformer 23 is used to detect failure of all three deflection yokes and to generate an output signal for CRT shutdown in response thereto. This approach thus requires three separate transformers which reduces its reliability.
These and other problems encountered in the prior art are avoided by the present invention which provides a system for preventing CRT phosphor burn in a multiple CRT projection type television system by means of a single transformer in each of the vertical and horizontal deflection systems.

Phosphor protection circuit for multiple CRT projection television


# # S T R 1 # #. A   p r o c e s s   f o r   p r e p a r i n g   a   c o m p o u n d   c o n t a i n i n g   ( a )   p e r o x y a c e t a l   l a c t o n e ,. ( b )   p e r o x y a c e t a l   l a c t o l   o r   ( c )   p e r o x y a c e t a l   e t h e r   f u n c t i o n a l i t y   c o m p r i s i n g. o x y g e n a t i n g   i n   t h e   p r e s e n c e   o f   o n e   o r   m o r e   o x i d i z i n g   m e t a l   c a t a l y s t s   a. c o m p o u n d   c o n t a i n i n g   ( i )   h y d r o p e r o x y   a l k e n e   c a r b o x y l i c   a c i d ,   ( i i ). h y d r o p e r o x y   a l k e n e   a l d e h y d e ,   ( i i i )   h y d r o p e r o x y   a l k e n e   k e t o ,   ( i v ). h y d r o p e r o x y   a l k e n e   a l c o h o l   f u n c t i o n a l i t y   o r   ( v )   d i a l k y l   a c e t a l s   o f. c o m p o u n d s   i n   ( i i )   a n d   ( i i i )   a b o v e .   F o r   e x a m p l e   ( I ) . f w d a r w . ( I I )   w h e r e i n. n = 1 ,   2   o r   3 ;   m = 0 ,   1 ,   o r   2 ,   p = 0 ,   1 ,   2   o r   3 ;   R . s u p . 5   = - - C O O H ,   - - C ( O ) R ,. - - C R O H ,   ( . a l p h a . ) ,   w h e r e   R   i s   H ,   a l k y l ,   a r y l   o r   a r y l a l k y l ;   R . s u p . 1   a r e. i n d e p e n d e n t l y   a l k y l ,   a r y l a l k y l   o r   e a c h   R . s u p . 1   t o g e t h e r   w i t h   t h e   g r o u p. - - O - - C - - O - -   t o   w h i c h   t h e y   a r e   a t t a c h e d   f o r m   a   c y c l i c   a c e t a l ;   X = C R . s u p . 2. R . s u p . 3 ,   O ,   S ,   S O ,   S O . s u b . 2   w h e r e   R . s u p . 2   a n d   R . s u p . 3   a r e   i n d e p e n d e n t l y. s e l e c t e d   f r o m   H ,   o p t i o n a l l y   s u b s t i t u t e d   a l k y l ,   o p t i o n a l l y   s u b s t i t u t e d. a r y l ,   a n d   w h e r e i n   w h e n   n & g t ; 1 ,   X   i s   i n d e p e n d e n t l y   s e l e c t e d   a n d   c a n   b e. b r a n c h e d   o r   s t r a i g h t   c h a i n   a n d   X   t o g e t h e r   w i t h   a   s u b s t i t u e n t   Y   c a n   a l s o. f o r m   a   r i n g ;   Y   i s   a   s u b s t i t u e n t   s e l e c t e d   f r o m   H ;   o p t i o n a l l y   s u b s t i t u t e d. a l k y l   o r   a r y l ;   Y   c a n   b e   o n   t h e   s a m e   C   a t o m   a s   t h e   h y d r o p e r o x y   g r o u p   a n d. a n y   C   a t o m   m a y   b e   d i s u b s t i t u t e d   b y   Y   a n d   i n c l u d e s   r e p l a c e m e n t   o f   H   a t o m ( s ). i n   " ( C H . s u b . 2 ) . s u b . m   "   b y   Y ;   R . s u p . 6   o r   R . s u p . 7   i s   a s   d e f i n e d   f o r   R   a b o v e ,. H ,   O H ,   O R . s u p . 1   o r   t o g e t h e r   w i t h   t h e   c a r b o n   a t o m   t o   w h i c h   t h e y   a r e. a t t a c h e d   f o r m   a   k e t o   g r o u p .   T h e   p r e s e n t   i n v e n t i o n   i s   p a r t i c u l a r l y. i m p o r t a n t   i n   i t s   a p p l i c a t i o n   t o   t h e   p r e p a r a t i o n   o f   b i o l o g i c a l l y   a c t i v e. c o m p o u n d s   c o m p r i s i n g   t h e   c y c l i c   p e r o x y a c e t a l   l a c t o n e   o r   l a c t o l. f u n c t i o n a l i t i e s .   O n e   s u c h   b i o l o g i c a l l y   a c t i v e   c o m p o u n d   i s   q i n g h a o s u. ( A r t e m i s i n i n )

The present invention is particularly important in its application to the preparation of biologically active compounds comprising the cyclic peroxyacetal lactone or lactol functionalities.
One such biologically active compound is qinghaosu (Artemisinin) which has the following formula: ##STR2##
Qinghaosu is a potent antimalarial which has been successfully used to treat patients suffering from malaria. The reemergence of strains of malaria resistant to conventional (chloroquine) therapy is posing a worldwide problem, and indeed, there is no universally acceptable cure at the present time. Qinghaosu occurs to the extent of about 0.1 (dry weight) in an annual shrub, qinghao or (Artemisia annua), which grows in most provinces of China. Unfortunately, the world demand for qinghaosu far exceeds the supply, and there is considerable pressure to develop bioactive analogues, or to develop alternative sources for the compound. The compound has been prepared by total synthesis in the laboratory, but the structural complexity is such that no total laboratory synthesis has been economically feasible.

Cyclic peroxyacetal lactone, lactol and ether compounds


A power control apparatus includes a plurality of transformers configured to transform power generated by a plurality of solar cell strings, and a controller configured to control the transformers. The transformers each include a diode configured to prevent a reverse flow of power to be output from the transformer itself and a switch configured to open or close a connection between the solar cell string and an inverter. When a diode of one of the transformers has failed to prevent the reverse flow of the power to be output from the one of the transformers, the controller first opens the switches of all of the transformers and then closes the switches of the transformers other than the switch of the one of the transformers.

In recent years, there has been known power control apparatuses such as power conditioners (inverters) that connect a plurality of solar cell strings together and control power generated by the plurality of solar cell strings. The power conditioners which have conventionally and popularly been used are of a single-type (or a centralized-type) that aggregate wiring of a plurality of solar cell strings in a connection box and control power output from the connection box. However, power conditioners employing a multistring scheme that allows direct connection of a plurality of solar cell strings together have recently been more popularly used.
The power conditioners employing the multistring scheme includes DC/DC converters having a maximum power point tracking (MPPT) function. Such a DC/DC converter, while adjusting respective voltages of the solar cell strings, controls respective operation points for producing maximum power. In this way, the power conditioner employing the multistring scheme may maximize respective power generation amounts of the respective solar cell strings.

Power control apparatus, power control system, and power control method


The present invention provides an etching liquid for a multilayer thin film containing a copper layer and a titanium layer, and a method of using it for etching a multilayer thin film containing a copper layer and a titanium layer, that is, an etching liquid for a multilayer thin film containing a copper layer and a titanium layer, which comprises (A) hydrogen peroxide, (B) nitric acid, (C) a fluoride ion source, (D) an azole, (E) a quaternary ammonium hydroxide and (F) a hydrogen peroxide stabilizer and has a pH of from 1.5 to 2.5, and a etching method of using it.

Heretofore, aluminium or an aluminium alloy has been generally used as the wiring material for display devices such as flat panel displays, etc. However, with growing in size and increasing in resolution of displays, there has occurred a problem of RC delay caused by the characteristics such as the wiring resistance of such aluminium-based wiring materials and uniform panel displaying has tended to be difficult.
Given the situation, the recent tendency is toward investigation of employing copper or copper-based wiring with a material having a lower resistance. However, copper has an advantage in that its resistance is low but, on the other hand, has a problem in that, in use for gate wiring, the adhesiveness between the substrate such as glass or the like and copper is not sufficient and that, in use for source/drain wiring, copper may diffuse into the silicon semiconductor underlayer. Consequently, for preventing these, there has been made an investigation of barrier layer lamination with a metal that has high adhesion to a substrate such as glass or the like, and hardly diffuses into the silicon semiconductor underlayer and additionally has a barrier property; and as the metal, titanium-based metals such as titanium (Ti) and titanium nitride (TiN) have become specifically noted.
A multilayer film that contains copper or a copper-based copper alloy is formed on a substrate of glass or the like according to a film formation process of a sputtering method or the like, and then processed in an etching process of etching it via a resist serving as a mask to give an electrode pattern. The etching process includes a wet etching mode of using an etching liquid and a dry etching mode of using an etching gas of plasma or the like. The etching liquid for use in the wet mode is desired to satisfy the following: (i) The processing accuracy is high, (ii) the amount of the etching residue is small, (iii) the etching unevenness level is low, and (iv) the etching ability to dissolve the metal of the copper-containing wiring material to be etched is stable; and in addition to these, for meeting the size enlargement and the resolution enhancement of displays, (v) the wiring configuration formed after etching could fall within a predetermined range, or that is, a good wiring configuration can be obtained. More concretely, the parameters shown in FIG. 1 are desired to be as follows: The angle (taper angle) between the etched face of the copper wiring edge and the underlayer substrate is from 20 to 60°, or that is, the angle is a regular taper angle; the distance between the resist edge and the wire edge to be in contact with the resist (top CD loss, a×2) is at most 3 μm, the distance between the resist edge and the wire edge to be in contact with the barrier layer provided below the wire (bottom CD loss, b×2) is at most 1 μm, and the barrier film tailing (c) is not more than b.
As the etching liquid to be used in the etching process for the multilayer film containing copper or a copper-based copper alloy, for example, there have been proposed an etching solution containing at least one selected from a neutral salt, an inorganic acid and an organic acid, and hydrogen peroxide and a hydrogen peroxide stabilizer (for example, Patent Reference 1), an etching solution containing hydrogen peroxide, an organic acid and fluorine (for example, Patent Reference 2), etc.
However, these are all unsatisfactory in point of the wiring profile after etching therewith and, as a result, could not often sufficiently meet the size enlargement and the resolution enhancement of displays.

Etching liquid for a copper/titanium multilayer thin film


An injection molding screw for use in processing heat sensitive polymeric materials and a process for plasticating such materials. The screw has an inlet end, a discharge end, means for mounting a backflow valve on the discharge end, and at least one section which applies high shear and high compression to the polymeric material and controls the material flow rate. A flighted screw section is disposed between the high shear and high compression section and the discharge end; that screw section includes means for decompressing the polymeric material and pumping it to the discharge end of the screw in the decompressed state at a rate at least equal to the pumping rate of the zone of high shear and high compression.

1. Field of the Invention
This invention relates to injection molding screws and more particularly to injection molding screws for use in processing heat sensitive polymeric materials. The invention also relates to an improved process for plasticating such materials in an injection molding machine.
2. Description of the Prior Art
The injection molding process involves feeding a particulate thermoplastic polymer into the hopper of an injection molding machine and thence through a zone where the polymer is plasticated into a melt which is then forced into a mold that conforms the polymer to a desired shape.
The injection molding process is extensively used in producing thermoplastic articles of a wide variety of shapes and sizes. The success of injection molding is attributable to several aspects of the process, the most important being the achievement of high production speeds and minimal waste. The production speeds are maximized by the continuous aspects of the process while material waste is minimized by an ability to reprocess waste thermoplastic polymer.
In addition to the inherent advantages of the injection molding process itself, the types of articles susceptible of fabrication by injection molding have continually expanded through the development of thermoplastic polymers having particularly desirable properties for specific applications and the discovery of techniques for processing such polymers in injection molding apparatus. The result has been the availability of a wide range of injection molded products having desirable chemical and physical properties specified by consumers of such products.
Thus, while any thermoplastic polymer may be processed in injection molding apparatus, the ability to achieve a useful end product depends upon the chemical and physical properties of the polymer and how these properties are affected by the process conditions within the injection molding apparatus. In accordance with the need to adjust processing parameters in the injection molding operation, four main types of systems have been developed to melt and inject the thermoplastic polymer. These systems are referred to as (1) reciprocating screw, (2) single stage plunger, (3) two-stage plunger and (4) fixed screw ram. Combinations of these systems have also been used.
The most widely used system is the reciprocating screw. In this system, a supply of the particulate thermoplastic polymer is maintained in a hopper which feeds the inlet end of a plasticating screw encased in a constant diameter barrel. Typically, the screw has three separate sections: (1) a feed section, (2) a transition section, and (3) a metering section. The hopper transfers (usually by gravity) particulate thermoplastic polymer to the feed section of the screw which has a constant root and a single helical flight of constant pitch. The distance from the land of the screw flight to the root (i.e. the channel depth) is sufficient to permit conveyance of the particulate polymer along the helical channel, while also providing for the application of shearing force to the polymer. The mechanical energy imparted to the polymer through the application of shear is converted to thermal energy and thereby the temperature of the polymer begins to rise. The screw conveys the polymer to the transition section where the root constantly increases in diameter with a resultant intensification of the shear and compression forces to which the polymer is subjected. In the transition section, the polymer begins to melt and be mixed, the objective being the eventual formation of a homogeneous, melted mass of polymeric material. From the transition section, the polymer proceeds to the metering section where compression and average shear are at their maximum levels and where the mass flow rate of polymer along the plasticating screw is regulated.
From the metering section, the polymeric melt is deposited in front of the discharge end of the screw. A backflow valve, which is mounted on the discharge end of the screw, prevents the reverse movement of material onto the screw. As the material is so deposited, the screw retracts until a predetermined space beyond the discharge end of the screw is filled with the polymer melt. When the desired amount of polymer accumulates in that space, the screw becomes a plunger, is moved forward, and forces the polymer melt into a mold or molds of specific shape. The melt is allowed to cool within the mold before the pressure is released. After cooling, the article thus formed is ejected from the mold and the process is repeated.
Although the three section screw is by far the most popular for use in the injection molding process, other screw designs have been used. For example, an injection molding screw may have more than one metering section. But common to all injection molding screws is the progressive average increase of root diameter from the inlet end to the discharge end with the feed section of the screw being characterized by low average shear and low compression and the discharge end being characterized by high average shear and high compression. When used herein, the term "high shear" means the maximum average mechanical force applied to the polymeric material when the material is subjected to high compression; and the term "high compression" means the maximum pressure to which the polymeric material is subjected during the plastication process.
Although conventional injection molding screws are satisfactory for the processing of many polymers, heat sensitive polymers present unique problems and have caused workers in the art to seek alternate screw designs. As used herein "heat sensitive polymers" means those thermoplastic polymers having threshold decomposition temperatures close to, or in the range of, the temperatures necessary for plastication. The difficulty in processing heat sensitive polymers with conventional injection molding screws centers around the inability of such screws to provide the necessary homogeneity in the final polymer melt without exceeding the time/temperature limits for preventing thermal decomposition of the polymer. Examples of such heat sensitive polymers are the chloro- and fluoro-hydrocarbon polymers and the polyesters.
In applications, for example, where the injection molded article is used to contain food, beverages or the like, even minute amounts of a polymer's thermal decomposition products may adversely affect taste; and because the polyesters, particularly polyethyleneterephthalate, are useful in this application, the thermal decomposition products thereof, specifically acetaldehyde, must be eliminated by proper processing to prevent imparting undesirable taste to the food or beverage.
Thus, in accordance with the present invention, an injection molding screw is provided which substantially eliminates thermal polymeric decomposition of heat sensitive polymers in the injection molding process. Further, the present invention provides a process for plasticating such polymers in an injection molding machine while avoiding thermal polymeric decomposition.

Injection molding using screw for processing heat sensitive polymeric materials