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There have been developed many bill handling machines such as vending machines, exchangers, automatic cash dispensers, automatic teller machines and bill validators mounted in gaming machines. Sometimes, these bill handling machines may encounter an illegal action by an imprudent person who fraudulently tries to extract a bill from inside of the machine by pulling out a string connected to the bill already received within the machine as a genuine one. To inhibit such a fraudulent action, some of these machines have an anti-pullback unit for preventing the bill from being taken out of the machine with any extracting tool.
U.S. 2006/284410A1 discloses a bill processing device which comprises a plurality of long channels disposed on a convexly bent path surface to form a bill path along a conveying direction of a bill and in parallel relation to each other in a transverse direction of the bill path, and a row of projections extending from respective side walls of the long channels. Each projection has a first surface inclined to a bottom surface side of the long channel to guide a foreign matter such as string or band conveyed with the bill to enter the long channel, and a second surface horizontal or inclined to the bottom surface side of the channel to inhibit string which has entered the long channel from exiting from the long channel. When string is connected to conveyed bill, it naturally enters long channel away from side wall to radially inward move along the first surface of the projection. Then, the string further goes into a recessed hole adjacent to the projection to effectively hinder escape of string from the recessed hole.
However, the disclosed bill processing device has a drawback in that disadvantageously it only has a single row of the stationary and irrotational projections not to wind or tangle string or band connected to the conveyed bill around projection and a bottom surface of the long channel. Accordingly, the prior art bill processing device would involve a large risk of inconvenient extraction of bill by drawing the string connected to bill.
Therefore, an object of the present invention is to provide a rotary anti-pullback unit of fletched fins for preventing extraction of a valuable document already received or stacked within an associated device by pulling out an extracting tool connected to the document. Another object of the present invention is to provide a rotary anti-pullback unit of fletched fins provided with a rotatable rotor capable of reeling an extracting tool connected to a document around the rotor to inhibit fraudulent extraction of the document. | {
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1. Field of the Invention
The present invention relates to a thermal printer and, more particularly, to an improvement in a thermal printer suitably used for preparing a block copy.
2. Description of the Prior Art
A typical conventional thermal printer is shown in FIG. 1. A thermal ink ribbon 3 overlays recording paper 2 wound around a platen 1. The thermal ink ribbon 3 and the recording paper 2 are selectively heated by a thermal head 4 to transfer ink from the ink ribbon 3 to the recording paper 2. In order to print a halftone image in a thermal printer, an image 5, divided into 1024.times.512 picture elements, is formed by scanning with the thermal head 4 having 512 heating elements 6 in the direction V indicated by the arrow shown in FIG. 2. In this case, the thermal head 4 is intermittently moved relative to the paper 1024 times for completing an image. The heating elements 6 are seleotively energized and heated for periods of time corresponding to the image densities of the picture elements. The elements 6 are intermittently stopped to print a line extended in the V direction (which is here-in-after referred to as a V line). It should be noted the head 4 in the printer of FIG. 1 is fixed, and that the platen 1 is intermittently rotated to perform the required scanning.
In order to reproduce a full-color image, four ink ribbon sheets such as Y (yellow), M (magenta), C (cyan), and B (black) color ink ribbon sheets are used, and scanning is performed one color at a time. In some case, B (Black) color printing may be omitted.
The above conventional printer is disclosed in U.S. Pat. No. 4,496,955.
In the field of full-color printing, when four block copies, i.e., Y, M, C, and B copies are prepared from a single full-color image, the full-color image is separated by a color scanner to obtain four monochromatic images whose densities respectively correspond to levels of Y, M, C, and B color components. These monochromatic images are converted into dot pictures to prepare the corresponding block copies.
The above method requires an expensive color scanner, and color separation is also cumbersome and time-consuming. | {
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Known carboxyl-terminal (C-terminal) sequencing methodologies are enzymatic physical or chemical. The enzymatic approach is basically a time-course carboxypeptidase procedure. It is limited by differential hydrolysis rates of the involved peptide bonds and by potential unaccessibility of the COOH carboxyl terminus in proteins. The results may include the correct amino acids but in the wrong order and may not extend to more than three to five amino acids.
Physical approaches include mass spectrometry and nuclear magnetic resonance (NMR) and are most suitable for small peptides. Fast atom bombardment--Mass Spectrometry (FAB/MS) sensitivity for determining an entire peptide sequence is in the range of 1-10 nmol and is limited to expensive multisector instruments. Micromolar samples are required for NMR analysis.
Four chemical methods of some interest are known. In 1978 Parkam and Loudon reported a method in which the carboxyamido peptide derivative is treated with bis(1,1 trifluoroacetoxy)iodobenzene to yield a derivative of the amino acid. Free COOH groups were treated with bis-p-nitrophenylphosphoryl azide to generate the carboxyamido derivative through a Curtius rearrangement..sup.1 FNT .sup.1 See, Parham, M. E. and Loudon G. M. Biochem. Biophys. Res. Commun. 80: 1; 7 (1978).
Loudon and coworkers presented another version of the method which entailed reaction of the COOH terminus with pivaloylhydroxyl amine in the presence of carbodimide to effect a Lossen rearrangement. This method failed to degrade aspartic and glutamine residues..sup.2 FNT .sup.2 See, Miller, M. J. and Loudon, G. M., J. Am. Chem. Soc. 97: 5296 (1975); Miller, M. J., et al., J. Org. Chem. 42: 1750 (1977).
The method reported by Stark.sup.3 releases the COOH-terminal amino acid as a thiohydantoin. It entails activation of the COOH group with acetic anhydride, followed by reaction with ammonium thiocyanate and cleavage by acid or base hydrolysis to release the thiohydantoin from the peptide chain. FNT .sup.3 See, Stark, G. R. Biochemistry 8: 4735 (1968); Stark, G. R. in "Methods in Enzymology", Vol. 25, p. 369, Academic Press, New York, N.Y. (1972).
Hawke reported a modification of the Stark chemistry in which trimethylsilylisothiocyanate is utilized as the coupling reagent..sup.4 FNT .sup.4 See, Hawke, et al. Analytical Biochemistry 166: 298-307 (1987).
Notwithstanding these procedures, there is a continuing substantial need for a generally applicable chemical method for C-terminal sequencing. Such a method would have particular value with respect to, among other things, sequencing N-terminal blocked polypeptides and proteins, verifying the primary protein structures predicted from DNA sequences, providing practical detection of post translational processing of gene products from known codon sequences, and as an aid in the design of oligonucleotide cDNA or gene bank probes. | {
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Recently, a treatment using a plasma (hereinafter, referred to as “plasma processing”) such as an etching, sputtering and CVD (chemical vapor deposition) has been employed to be performed on an object to be processed such as a semiconductor wafer (hereinafter, referred to as “wafer”) in a manufacturing process of a semiconductor apparatus.
An apparatus for carrying out such process (shown in FIG. 8) has a processing chamber 800, which is a cylindrical container, for performing a plasma processing on a wafer. The processing chamber 800 includes a chamber sidewall 810, an upper electrode 811 installed at the top of the chamber 800, a lower electrode 812 installed in a lower portion of the processing chamber 800, an ESC (electrostatic chuck) stage 820 and a focus ring 821 mounted on an upper side of the lower electrode 812, and a baffle plate 830 interposed between the chamber sidewall 810 and the lower electrode 812.
The upper electrode 811, which has a plurality of through holes not shown in the drawing, serves as a shower head for introducing a process gas for the plasma processing into the processing chamber 800 through the through holes. The lower electrode 812 is connected to a high frequency power supply 813. The focus ring 821 is made of a ring-shaped member formed to enclose a wafer mounted on the upper side of the ESC stage 820.
The ESC stage 820 includes an ESC electrode 820a embedded in the ESC stage 820 to electrostatically adsorb the mounted wafer onto the ESC stage 820. The ESC electrode 820a is connected to a variable power supply 822 for providing electric power required to adsorb the wafer onto the ESC electrode 820a.
In the plasma processing apparatus shown in FIG. 8 is formed a plasma region of the plasma generated by a high frequency electric field formed in a space between the upper electrode 811 and the lower electrode 812 as shown in the figure. The plasma processing apparatus performs an etching on, for example, an oxide film already formed on an upper side of the wafer by the generated plasma. The particles detached from an inner wall of the chamber sidewall 810 by the etching float around inside the processing chamber 800. After the etching is completed, the particles are removed by exhausting the processing chamber 800 through a small through hole (not shown) located in the baffle plate 830 by using a pump which is not shown.
Such particles are negatively charged by the electrons in the plasma to float around the plasma region above the wafer during the etching process, and will be attached onto the upper side of the wafer to thereby contaminate the wafer after the plasma production is stopped by completing the etching process.
There are disclosed techniques that can be employed to prevent the particles from being attached onto the upper side of the wafer as described above, wherein the charged particles are actively removed by using another electrode installed in the processing chamber 800 before the plasma generation or after the plasma extinction (for example, References 1 and 2). (Reference 1) Japanese Patent Laid-open Application No. H10-284471 (Reference 2) European Patent Publication No. 1119030
However, although the particles can be driven from the region above the wafer towards the other electrode before the plasma being generated or after the plasma being extinguished by the techniques described in References 1 and 2, it is not practical to remove the particles while the plasma is being produced because the other electrode causes to generate an abnormal discharge or to produce particles during the plasma generation.
Further, since the particles in the region above the wafer effectively mask the parts to be processed on the wafer to thereby reduce the yield, it is required that these particles have to be purged out of the region above the wafer especially while the plasma is being generated. In addition, by suppressing the yield reduction, the productivity is expected to improve. | {
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The present invention relates to a new and improved construction of a chair or the like, whose chair frame is equipped with a seat portion and a backrest portion and is supported on a support or carrier portion forming part of the chair pedestal or base and which support or carrier portion is provided with a projecting support arm.
Numerous different constructions of such type chairs are well known in this art. In order to increase sitting comfort, it is known to construct the seat portion so as to pivot or swivel with respect to the support or carrier portion or part, a spring element exerting an opposing force for supporting the body weight of the sitting person or occupant. If the seating comfort is to be further increased, particularly through the sitting person assuming a so-called relax or reclined position, it is also known to pivot the backrest portion with respect to the seat portion. Here again it is necessary to produce an opposing force by one or more correspondingly positioned spring elements to the forces exerted on the backrest portion by the chair occupant.
The forces exerted by the occupant on the seat portion and the backrest portion and which are transferred to the support or carrier portion or part are considerable. In the case of chairs with a pivotable seat portion and/or a pivotable backrest portion, it is necessary to support these two chair portions for ensuring the mobility thereof on a chair frame. The term chair frame is here understood to encompass components, elements or parts such as links or link elements or brackets, levers and spring elements, with the aid of which the seat portion and the backrest portion are supported on the support or carrier portion or part. However, as the chair frame must be accommodated in a minimum amount of space, as a result of the nature of the arrangement of these components, elements or parts, they must partially absorb much higher forces than merely that of the body weight of the chair occupant and, in particular, the spring elements must be designed to take-up quite considerable forces. They therefore have an unfavorable influence on the manufacturing costs. | {
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The present invention relates to a process for manufacturing lids, in particular lids for beverage cans. Such lids are most often made of aluminum (pure aluminium or an aluminium alloy), tin plate or tin free steel (TFS) and are usually coated, at least on the inside face, with a protective layer of lacquer e.g. a phenolic epoxy based lacquer.
It is known to provide such lids with a pouring hole or group of holes and, if desired, at least one air inlet hole.
These holes are then covered over with a sealed on, pull-off closure strip. Such strips are, advantageously, made of an approximately 0.9-0.14 mm thick aluminium foil which is coated on the side to be sealed to the lid with a coating of thermoplastic plastic e.g. about 0.015-0.03 mm thick, usually about 0.02 mm thick. Before applying that plastic layer, however, the aluminium is usually coated first with a thinner layer of phenolic epoxy lacquer. The outside of the strip is usually covered with a decorative lacquer coating. Strips of aluminum-polyamide laminate, in particular with a polyamide-12 coating, have proved to be very suitable for this purpose.
For production reasons the lid material is lacquered in strip or sheet form and the lids prepared from that with the pouring and, if desired, airing holes being punched out of the material in the process. The result is, however, that the cut edges around the holes are then left unprotected. These unprotected edges are undesireable as they are exposed to corrosive attack by the contents, in particular by such ones containing CO.sub.2 ; the corrosion products could lead to spoiling of the contents. Such a phenomenon is already found to occur to a moderate degree with aluminium lids; it is however more pronounced in the case of lids made of ferrous material (tin plate or TFS). For example at a concentration of only 1 mg Fe-ions per liter beer becomes cloudy, also some cola drinks at a concentration of 1.5 mg Fe per liter. | {
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1. Field of the Invention
The present invention relates to a method for manufacturing semiconductor structures.
2. Description of the Prior Art
Conventional planar metal-oxide-semiconductor (hereinafter abbreviated as MOS) transistor has difficulty when scaling down to 65 nm and below. Therefore the non-planar transistor technology such as Fin Field effect transistor (FinFET) technology that allows smaller size and higher performance is developed to replace the planar MOS transistor.
Since the manufacturing processes of the FinFET device are easily integrated into the traditional logic device processes, it provides superior process compatibility. More important, since the FinFET device increases the overlapping area between the gate and the substrate, the channel region is more effectively controlled. This therefore reduces drain-induced barrier lowering (DIBL) effect and short channel effect. In addition, the channel region is longer under the same gate length, and thus the current between the source and the drain is increased.
However, the FinFET device still faces many problems. For example, because the fin structures include a thin and slim configuration, it is always difficult to improve process control. There is therefore a continuing need in the semiconductor processing to improve the process control and to obtain the fin structures having desirably expected profile. | {
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Use of pre-processed foods, both in homes and in restaurants, has created a demand for high-capacity automated food processing equipment. That demand is particularly evident with respect to hamburgers, molded steaks, fish cakes, and other molded food patties.
Food processors utilize high-speed molding machines, such as FORMAX F-6, F-12, F-19, F-26 or F-400 reciprocating mold plate forming machines, available from Formax, Inc. of Mokena, Ill., U.S.A., for supplying patties to the fast food industry. Prior known high-speed molding machines are also described for example in U.S. Pat. Nos. 3,887,964; 4,372,008; 4,356,595; 4,821,376; and 4,996,743 herein incorporated by reference.
Although heretofore known FORMAX patty-molding machines have achieved commercial success and wide industry acceptance, the present inventors have recognized that needs exist for a forming machine having an even greater energy efficiency, an even greater durability and an even greater duration of maintenance free operation. The present inventors have recognized that needs exist for an enhanced controllability and ability to tune a patty-forming machine for particular food materials to be processed, for an enhanced effectiveness of a patty-forming machine in producing uniform patties, for an even greater output rate of patties from a patty-forming machine, for an enhanced convenience for cleaning and maintenance of a patty-forming machine, and for a smoother and quieter patty-forming machine operation. | {
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(1) Field of the Invention
The present invention relates to devices for handling articles in general and more particularly to automatic devices for depalletizing/palletizing boxes and manipulating them, for instances, for transferring them from one position to another as on an assembly line.
(2) Prior Art
In order to reduce product cost, improve product quality and increase product throughout, the current trend in industry is to automate the assembly lines that manufacture the product. Automated assembly lines necessitate the use of robotic systems for performing tasks that were formerly done by humans. A fully automated assembly line includes a conveyor system with a plurality of workstations disposed along the conveyor system. The conveyor system transports the components that are used to manufacture the product while the actual fabrication of the product is done at the different workstations.
Each workstation is fitted with a robotic system designated to perform an assigned task. Included in the assigned task is the depalletizing of boxes. Usually, the boxes carry the components that are used in the fabrication of a particular product. Other tasks include opening the boxes, removing the components from the boxes, assembling the component in a finished product, testing the product, packaging the product, and palletizing the product for shipment to the ultimate user.
The typical robotic system includes a robot and an article handling system connected to the robot. The article handling system is usually designed to handle and/or manipulate the article while the robot is the mechanism that move the article handling system and its attached article to a designated point. Article handling systems may be broadly classified into two types, namely: the gripping type and the lifting type.
The gripping type article handling systems invariably include a gripping mechanism that attaches to the top of an article, such as a box, and moves said article from one position and/or place to the next. Such gripping mechanism may include suction cups to which a source of negative pressure is applied to effectuate attachment to the article. Alternately, attachment may occur by magnetic means and/or mechanical means. U.S. Pat. Nos. 4,266,905; 4,299,533; 4,242,025 and 4,392,766 describe gripping mechanisms in which negative pressure is used to effectuate attachment.
On the other hand, the lifting type article handling systems may be considered to be reminiscent of the fork lift devices used in warehouses to move articles. Such devices consist of a pair of spaced forks or lifting elements which are inserted under the bottom side of the article. As a result, the article sits on the forks and is relocated.
Although the above identified article handling systems work well for the intended purpose, they all handle the boxes from either the top side or the bottom side and as such are not suitable for use on the type of automated manufacturing lines wherein the components for manufacturing the product are provided in boxes (such as cartons) having removable covers (shoe box style). Since the top covers are loose, such cartons cannot be handled and/or depalletized by holding onto the covers. | {
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Set accelerators are used when it is necessary to work with hydraulic cement compositions at freezing or near-freezing temperatures. The rate of hydration of Portland cement, for example, is very dependent on temperature, such that, at lower temperatures, Portland cement compositions will often harden at a rate slower than desired unless the hardening process is accelerated. In addition to accelerating the set, it is desirable to also attain an increase in the rate of early strength development at normal or low temperatures. This reduces curing and protection periods necessary to achieve specified strengths in concrete. Some techniques for accelerating the set are: increasing the proportion of cement in the mix, heating the mix, and using chemical admixtures that act on the components of the mix to increase the rate at which the cement paste sets.
Several chemical set accelerators are well-known. They include alkali hydroxides, silicates, fluorosilicates, calcium formate, sodium chloride, calcium chloride, and calcium nitrate and calcium nitrite.
Calcium chloride is widely used because it is easy and inexpensive to produce and its effects on hydraulic cement are predictable and well-documented. However, like sodium chloride, it has the disadvantage of corroding steel. Thus, it can cause the corrosion of steel reinforcing bars in concrete. Other drawbacks of calcium chloride use include reduced compressive strength at later ages, reduced response to air entrainment, and blotching of hardened concrete surfaces (Concrete Admixtures, Dodson: Van Nostrand Reinhold, 1990).
It is thus an object of this invention to provide new set-accelerating admixtures which reduce the set time of hydraulic cement compositions at lower temperatures, without inducing or promoting corrosion of steel reinforcement. Further objects of the invention are to provide methods for preparing such cement compositions and to provide methods for reducing the set time of hydraulic cement compositions. | {
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To monitor and control operation of internal combustion engines, one or more sensor may be arranged at suitable position of the internal combustion engine. Those sensors monitor operating conditions of the internal combustion engine such as pressure and/or temperature values, for example, within each cylinder of the internal combustion engine.
A sensor may be provided within a cylinder head covering a cylinder liner. The sensor may sense operating conditions such as combustion temperature and/or combustion pressure within the cylinder during operation of the internal combustion engine.
For example, DE 10 2010 048 464 A1, discloses a pressure sensor arranged in a sensor shaft of the cylinder head. Specifically, an outer thread of the sensor may be screwed into an inner thread of the sensor shaft to mount the sensor in the cylinder head.
Machining of a sensor seat and a thread within a sensor shaft extending through a cylinder head may require expensive special tooling and may be difficult and complex to machine.
As a further example, US 2009/0126472 A1 discloses a combustion pressure sensor having a housing with a fixing functional member fixed to an engine head.
FR 2 656 247 A1 discloses a flexible device for fitting refrigerated inserts such as valve seats and valve guides in a cylinder head of an internal combustion engine.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems. | {
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Application of a multicoloring technique making use of a color conversion method to liquid crystal displays, organic electroluminescent (EL) displays, lighting devices, and other devices is being energetically studied. Color conversion means conversion of light emitted from a light-emitting body into light having a longer wavelength, and, for example, indicates conversion of blue light emission into green or red light emission.
A composition having such a color conversion function (hereinafter, referred to as a color conversion composition) is used, and combined with, for example, a blue light source, whereby the three primary colors, namely, blue, green, and red can be extracted, in other words, white light can be obtained from the blue light source. A white light source obtained by combining the blue light source with the composition having the color conversion function is used as a backlight unit, and a combination of a liquid crystal driving unit and color filters allows a full-color display to be produced. Without the liquid crystal driving unit, the residual part can be used as a white light source as it is, which can be applied as a white light source such as light-emitting diode (LED) lighting using an LED.
Examples of a problem with a liquid crystal display making use of a color conversion system include the enhancement of color reproducibility. To enhance color reproducibility, making a full width at half maximum of each of blue, green and red emission spectra of a backlight unit narrower and thereby enhancing the color purity of each of blue, green and red are effective.
To solve this problem, there has been proposed a technique of using a combination of a light emitting body having a light emission peak wavelength in a wavelength range of 240 nm to 560 nm, a green phosphor having a light emission peak wavelength in a wavelength range of 510 nm to 550 nm, a red phosphor activated by a tetravalent manganese ion, and a color filter having a blue pixel in which the difference between the maximum and the minimum of a transmittance in a wavelength range of 420 nm to 460 nm in a spectral transmittance curve is 4% or smaller (for example, see Patent Literature 1). | {
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This invention relates generally, as indicated, to light emitting panel assemblies.
Light emitting panel assemblies are generally known. However, the present invention relates to several different light emitting panel assembly configurations which provide for better control of the light output from the panel assemblies and more efficient utilization of light to suit a particular application. | {
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The present invention pertains generally to optical communication devices and pertains more particularly to optical waveguides that provide Raman amplification.
Current telecommunication and computer network services demand high-capacity communication systems. This demand is often satisfied by optical communication systems in which voice and data signals, represented by optical signals, are conveyed through optical waveguides such as silica fibers. Many optical communication systems are able to achieve better performance by using one or more types of optical amplifiers to increase the intensity of the optical signals. Typically, these optical amplifiers are driven by a source of optical energy known as pumping energy.
The demand for communication system bandwidth is growing rapidly. One technique known as wavelength division multiplexing (WDM) is often used in optical communication systems to meet this growing demand in a cost-effective manner by more fully utilizing the capacity of existing communication facilities. In many practical communication systems, however, the increase in capacity achieved by WDM is restricted by the fact many optical amplifiers can provide gain within only a fairly narrow bandwidth.
The erbium-doped fiber amplifier (EDFA) is one common type of optical amplifier that exhibits this limitation. An EDFA can provide reasonable gain for optical signals having a wavelength of about 1.5 xcexcm but it cannot provide a useful amount of gain for optical signals having a wavelength of about 1.3 xcexcm. As a result, the 1.3 xcexcm portion of the bandwidth is generally underutilized in optical communication systems that incorporate EDFA. This is particularly unfortunate in systems that use silica fiber because signal losses in such fiber are usually lower for wavelengths at 1.3 xcexcm than they are for wavelengths at 1.5 xcexcm.
This limitation in bandwidth can be avoided by using a so called Raman amplifier that achieves amplification through a phenomenon known as Raman scattering. Like EDFA, a Raman amplifier requires a source of pumping energy; however, the level of pumping energy must be considerably higher to achieve reasonable gain. Unlike EDFA, no special doping is required for a Raman amplifier. This feature is particularly attractive because a Raman amplifier can be incorporated into existing optical fibers by merely providing a suitable source of pumping energy. Furthermore, unlike the amplification provided by an EDFA, Raman amplification occurs over a fairly wide bandwidth that is to a large extent dependent upon only the wavelength of the pumping energy.
Unfortunately, a Raman amplifier can be noisier than many other types of optical amplifiers like an EDFA, for example. One source of noise is the Raman scattering mechanism itself, which readily couples intensity fluctuations of the pumping energy into the signal to be amplified. This problem can be mitigated by using counter-propagating pumping energy, which propagates in a direction counter to or opposite the propagation direction of the signal to be amplified.
Another source of noise in Raman amplification is due to variations in amplifier gain caused by fluctuations in the polarization orientation of the pumping energy. Although polarization-induced gain effects tend to be averaged along the length of a Raman amplifier, there are some situations in which the averaging effect does not occur because a particular polarization orientation exists throughout an appreciable portion of the amplifier length.
Although wide-bandwidth Raman amplification is possible in principle, a Raman amplifier is not very useful in a communication system if the spectral gain characteristic or spectral shape of the gain profile across frequency is highly irregular or nonuniform. As may be understood from the discussion above, the spectral gain characteristic of a Raman amplifier is determined essentially by the spectral shape and intensity of the pumping energy. Unfortunately, it is generally more costly to provide pumping energy having an appropriate polarization and sufficient intensity at the proper wavelengths that causes Raman amplification to have a reasonably flat spectral gain characteristic.
It is an object of the present invention to provide for a wide bandwidth optical amplifier having a reasonably flat spectral gain characteristic.
According to one aspect of the present invention, an optical amplifier comprises an optical waveguide having a first end and a second end, wherein a signal is received through the first end, is amplified by Raman amplification as it propagates within the optical waveguide from the first end to the second end, and is transmitted through the second end; a pumping energy source optically coupled to the optical waveguide to provide pumping energy that causes the Raman amplification to have a spectral gain characteristic; and a reflector having an input optically coupled to the second end of the optical waveguide and having an output, wherein the reflector receives the amplified signal through the input and reflects it through the output, and wherein the amplified signal is modified by the reflector according to a property that is complementary to the spectral gain characteristic of the Raman amplification.
The various features of the present invention and its preferred implementations may be better understood by referring to the following discussion and the accompanying drawings in which like reference numerals refer to like elements in the several figures. The contents of the following discussion and the drawings are set forth as examples only and should not be understood to represent limitations upon the scope of the present invention. | {
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Medical devices have many applications in the context of modern medicine. Medical devices can include external devices and implantable devices. Devices can be formed of various materials including metals, ceramics, polymers and the like. The usability and/or efficacy of medical devices can be impacted by the functional properties they possess. As such, medical devices can be enhanced through the incorporation of various desirable functional properties. | {
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Congestive Heart Failure (CHF) is a form of heart disease still increasing in frequency. According to the American Heart Association, CHF is the “Disease of the Next Millennium”. The number of patients with CHF is expected to grow even more significantly as an increasing number of the “Baby Boomers” reach 50 years of age.
CHF is a condition that occurs when the heart becomes damaged and reduces blood flow to the organs of the body. If blood flow decreases sufficiently, kidney function becomes impaired and results in fluid retention, abnormal hormone secretions and increased constriction of blood vessels. These results increase the workload of the heart and further decrease the heart's pumping ability and, in turn, causes further reductions in blood flow to the kidney. It is believed that the progressively-decreasing perfusion of the kidney is a principal non-cardiac cause perpetuating the downward spiral of the “Vicious Cycle of CHF”. Moreover, the fluid overload and associated clinical symptoms resulting from these physiologic changes are a predominant cause for excessive hospital admissions, poor quality of life and large costs to the health care system due to CHF.
There is a long-felt demand for a miniature and portable extracorporeal fluid treatment devices for patients suffering from repeated fluid overload. Such a device might be worn during the day as the patient moves about. The device would preferably be easy to use. If the procedure for inserting catheters percutaneously is too complicated, it will be difficult to have sufficiently trained clinical personnel available to insert the catheter. Standard OTN (Over The Needle) catheters generally require nurses with intravenous (IV) insertion experience to insert catheters to gain blood access for the fluid removal device. When midline catheters are used for accessing blood peripherally, the insertion of the catheter is limited to clinicians with the required training. To insert PICC (Peripherally Inserted Central Catheter) line requires IV nurses with training in seldinger insertion technique and doctors with similar training.
Utilizing an ultrafiltration fluid removal device that uses standard IV access would greatly simplify the process. A simpler approach would be to use an implanted port whereby the nurse could quickly gain access to blood flow. Implanted ports are commonly used for drug infusion therapies and are ideal for long term access. Implanted ports are also accessed via IV needles. Ports have reduced infection rates when compared with standard central venous percutaneous catheters and are ideal for repeatable access over long periods of time.
Peripheral IV blood access is not without its own inherent issues, which include: (1) The blood flow may be limited and intermittent with peripheral access because the further down the peripheral vein tree blood flow is accessed there is less blood flow is available and the more that the available blood flow is subject to fluctuations in flow. Implanted ports can overcome many of these limitations because they are placed centrally. (2) The majority of nurses are comfortable using OTNs with sizes of 20 G and less. These are simpler to insert, cause less trauma and facilitate multiple insertions. If larger catheters gauge sizes are required, the percentage of nurses that can gain access without trouble quickly diminishes which would cause a further hurdle to the usage of such an ultrafiltration device. However, the smaller the gauge size of the catheter the smaller its internal diameter which results in a limitation in the maximum blood flow that can be achieved. This limitation is due to the maximum positive and negative pressures that blood can safely be exposed to without compromising patient safety. Patients with fluid overload also suffer from peripheral edema and the edema tends to hide the veins by placing them further from the skin surface making it more difficult to locate them. In these cases the clinician resorts to multiple sticks before a vein is located. The smaller the IV catheter the more acceptable such a procedure is. Larger gauge needles increase the trauma to the arm and are less acceptable to patients. Implanted ports will overcome many of these limitations because access is gained via a septum which when located makes gain blood flow access relatively simple.
When low blood flow is used in an extracorporeal device, it creates a significant engineering challenge. In general the lower the blood flow, the longer the residence time of blood extracorporeally and the greater the propensity of the device to clot. Lower blood flows increases the difficulty of pressure sensors to reliably detect infusion disconnects. Lower blood flows yield lower pressure drops that result in a large pressure sensor signal to noise ratio between the pressure drop attributed to the access and variations in pressure due to patient movement. When peripheral vein access is used or when a patient is treated for an extended period of time, it is normal to expect the patient to be mobile and that the patient will move about, bend over and lift their arms to stretch occasionally during treatment. Every centimeter (cm) in height change of the patient's arm having the withdrawal and/or infusion catheter results in a 0.75 mmHg pressure increase or decrease in the blood circuit due to the resultant change in static head pressure. Accordingly, the ratio between variation in static head pressure due to patient movement and needle pressure drop due to blood flow should be relatively insignificant so that false alarms will not be annunciated. Disconnection of blood tubes/access in the circuit are generally detected by a reduction in the pressure drop across a needle. It may be hard to distinguish pressure fluctuations due to patient motion and to needle disconnects. It is accepted medically that a blood loss of 100 ml or less will not result in the patients' health being compromised. In the case of the typical dialysis machine this time period is 100 ml/400 ml/min or 15 seconds. Disconnection algorithms have to be extremely sensitive to ensure patient safety. In hemodialysis standards, such as IEC 60601-2-16, the standards committee was aware that there are inherent limitations in using pressure measurements for detecting disconnects which is why devices which use high blood flows have been limited to ICU and dialysis clinic use up until recently. It is also recognized as being an increased risk for the use of home dialysis. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of Invention
The inventive concepts disclosed and claimed herein relate generally to improved methods for clean-up of oil spills and, more particularly, but not by way of limitation, to methods for clean-up of oil spills using onium halides to disperse and solubilize chemical constituents of the oil.
2. Brief Description of Related Art
Oil spills have become an international problem. Oil spills often result from oil tanker accidents; however, a number of other causes of oil spills exist including offshore drilling spills and blow-outs, land run-off, natural seepage, etc. The toxic nature of crude petroleum makes such spills a hazard to life in the oceans, on the oceans, and by the oceans, presenting a toxic environment for marine life, waterfowl, and other animals until effectively cleaned up. The most general means for clean-up are physical in nature: burns, containment booms, sorbents, and vacuums (pumps).
Use of chemicals in oil spill clean-up gets only minor consideration because of their general lack of effectiveness. For example, the COREXIT™ 9500 Dispersant used in the 2010 Gulf of Mexico oil spill, is not technically a dispersant, but rather an emulsifier causing water-in-oil emulsions. Proposed here are a class of chemicals that are not only useful for cleaning oil-contaminated areas, they are very effective for the clean-up of oil spills.
To this end, a need exists for methods capable of remediating oil contamination and for clean-up of oil spills. It is to such a process that the inventive concepts disclosed and claimed herein are directed. | {
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In an image forming device such as an electrophotographic device and an electrostatic recording device, first, an electrostatic latent image formed on the photoconductor is developed by a toner. Next, as needed, the thus-formed toner image is transferred onto a transfer material such as a paper and then fixed by various methods such as heating, applying pressure, and solvent fume.
The above-mentioned toner obtains desired flowability and charging characteristics by attaching an external additive to the surface of colored resin particles. As the external additive, fine particles composed of an inorganic or organic material are widely and generally used.
A toner is disclosed in Patent Literature 1, which is characterized in that the liberation rate of liberated mother particles to which silica is not attached, is set to be 10% or less, and the liberation rate of liberated silica, which is silica that is not attached to the mother particles, is set to be 0.2% to 10%. Also, Patent Literature 1 describes that the toner can improve low-temperature fixability, with preventing toner filming on toner-contact members. | {
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The present invention relates to an electrochemical device for measuring the concentration of oxygen in a liquid alkali metal and, more particularly, to such a device which has a longer life and is more reliable and accurate than prior devices of this nature especially designed to measure the concentration of oxygen in molten sodium.
It is desirable for various purposes to be able to measure the oxygen content of molten alkali metals used in industrial processes and commercial equipment. For example, it is quite important to be able to detect the presence of oxygen in the liquid sodium heat transfer loops of liquid metal fast breeder reactors. The presence of oxygen in the liquid sodium coolant of the primary coolant loop in such a reactor, i.e., the loop which passes through the reactor core, has to be minimized to prevent corrosion and consequent mass transport from the reactor core of radioactive corrosion products. A reliable oxygen monitoring device is also needed for the secondary loop of such a reactor liquid sodium coolant system in order to provide prompt and quantitative detection of steam or water leaks into the sodium.
Oxygen monitoring devices which rely on galvanic principles and ionic conduction have been designed to measure oxygen concentrations in molten metals. Basically, such devices provide an indication of the oxygen content by measuring the electromotive force generated between a reference electrode and a molten metal by the conduction of oxygen ions therebetween through a solid electrolyte. The devices described in U.S. Pat. Nos. 3,776,831; 3,864,231; and 3,864,232 are representative of such devices. Presently available electrochemical oxygen monitoring devices, however, suffer from several deficiencies which make them less than optimum for use in measuring the oxygen content in liquid alkali metals, especially if the alkali metal is, for example, liquid sodium being used as a fission reactor coolant.
One of the primary problems with most presently available devices is that they are not as accurate as desired. That is, most of such devices use air or some other gas as a reference electrode, and in order to provide a sufficiently fast response time the device must be operated at a relatively high temperature, e.g., 800.degree. C. The difficulty with operation of such a device with a gas reference electrode at such a high temperature is that electronic conduction through the electrolyte becomes sufficiently high to interfere with the accurate measurement of ionic conduction through the solid electrolyte. Moreover, high temperature operation substantially increases corrosive action of the alkali metal on the solid electrolyte, thereby reducing the effective life of the device. While it may appear that such problems could be circumvented by operating at a lower temperature, for example, at temperatures around 550.degree. C., such devices generally become irreversible with consequent potential drift during operation.
Also most presently available devices will not provide accurate readings when initially immersed in a liquid alkali metal having a concentration of oxygen in the range of parts per million. The electrolyte material used in such devices is generally comprised of a stoichiometric ceramic composition that has oxygen atoms removed when initially immersed in the alkali metal until an oxygen-depleted composition in equilibrium with the alkali metal is achieved. This removal of oxygen atoms from the electrolyte interferes with the accuracy of the operation of the device until an electrolyte with an oxygen depleted composition is achieved. Generally the kinetics of such removal of oxygen atoms from the electrolyte of the immersed device is very slow and a period of two or three months is required until the electrolyte material is in equilibrium with the alkali metal. | {
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The present invention relates to a grout bag, sometimes referred to as an inflatable bag, for use in mine support and also to a method of installing the support.
Such grout bags are used to support the hanging wall or roof in underground mining operations relative to the footwall or floor. The grout bags generally are filled with a liquid settable grout which sets solid using cementitious or other suitable binding material.
Props have been used for supporting the mine roof for many years. More recently inflatable grout bags have been employed as mine props whereby they are positioned in a deflated condition with the upper end thereof secured to the mine roof. The bag is then inflated to a substantial pressure with a settable grout and thereafter permitted to cure.
Such grout bags are also referred to as pillar bags and they are generally supported and reinforced over their vertical length by metal hoops or other reinforcing structure against expansion in the traverse direction when filled with a liquid settable material.
Problems incurred with existing grout bags are that they are generally expensive because of the associated elaborate reinforcing structures employed and further because considerable labor is involved in their erection. Additionally, reinforced grout bags of the prior art have insufficient load carrying capacity. Such prior art grout bags usually have a residual load capacity of approximately 250 kips to 300 kips, 125 tons to 150 tons, with about 9″ of displacement. It is a principal object of the present invention to provide a pumpable crib bag having a residual load capacity which is exceptionally greater. | {
"pile_set_name": "USPTO Backgrounds"
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In three-dimensional printing, building material is selectively jetted from one or more printing heads and deposited onto a fabrication tray in consecutive layers according to a pre-determined image data. In printing machines that utilize photopolymers as building material, the liquid layers are solidified, conditioned or cured using a radiation source. The radiation source may emit light such as ultraviolet (UV) light according to predetermined working parameters, such as output radiation intensity and spectral region. Formation of high-quality 3D objects requires maintaining the radiation power and wavelength region substantially constant. For example, the radiation power may only vary within ±5%-±10%. The intensity of the light source, however, may decrease in more that 10% from various reasons including deterioration of the light source, deterioration of a reflector of the light source, appearance of mist or undesired splashes of material on the protective glass of and the like. Further, the desired spectral region of the light source may shift so that light may be at less effective wavelengths. Accordingly, there is a need to monitor the radiation power and other characteristics of the radiation source.
It will he appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function. | {
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Medical privacy, also known as health privacy, is the practice of keeping information about a patient confidential. In the modern electronic age, this typically involves the security of medical records stored in health information systems. Another aspect of medical privacy involves the physical privacy of patient health information from third parties (e.g., other patients, providers, etc.) in a medical facility. With the proliferation of mobile recording devices (e.g., smartphone, tablets, wearable computers, etc.) equipped with, for example, a microphone and/or camera, new concerns are raised about inadvertently disclosing sensitive patient information to unauthorized third parties with such devices in the vicinity. | {
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Field of the Invention
The teachings herein are directed to intervertebral scaffolding systems having a stabilizer for stabilizing and/or retaining support beams upon expansion of the scaffolding in an intervertebral disc space.
Description of the Related Art
Bone grafts are used in spinal fusion, for example, which is a technique used to stabilize the spinal bones, or vertebrae, and a goal is to create a solid bridge of bone between two or more vertebrae. The fusion process includes “arthrodesis”, which can be thought of as the mending or welding together of two bones in a spinal joint space, much like a broken arm or leg healing in a cast. Spinal fusion may be recommended for a variety of conditions that might include, for example, a spondylolisthesis, a degenerative disc disease, a recurrent disc herniation, or perhaps to correct a prior surgery.
Bone graft material is introduced for fusion and a fusion cage can be inserted to help support the disc space during the fusion process. In fact, fusion cages are frequently used in such procedures to support and stabilize the disc space until bone graft unites the bone of the opposing vertebral endplates in the disc space. A transforaminal lumbar interbody fusion (TLIF), for example, involves placement of posterior instrumentation (screws and rods) into the spine, and the fusion cage loaded with bone graft can be inserted into the disc space. Bone graft material can be pre-packed in the disc space or packed after the cage is inserted. TLIF can be used to facilitate stability in the front and back parts of the lumbar spine promoting interbody fusion in the anterior portion of the spine. Fusion in this region can be beneficial, because the anterior interbody space includes an increased area for bone to heal, as well as to handle increased forces that are distributed through this area.
Unfortunately, therein lies a problem solved by the teachings provided herein. Currently available systems can be problematic in that the methods of introducing the fusion cage and bone graft material leaves pockets in regions of the intervertebral space that are not filled with bone graft material, regions in which fusion is desired for structural support. These pockets can create a premature failure of the fused intervertebral space due to forces that are distributed through the regions containing the pockets, for example, when the patient stands and walks.
Traditional fusion cages, such as the Medtronic CAPSTONE cage, are designed to be oversized relative to the disc space to distract the disc space as the entire cage is inserted. However, this makes it difficult to insert and position properly. In response to the problem, the art has developed a number of new fusion cages, such as the Globus CALIBER cage which can be inserted at a low height and expanded vertically to distract the disc space. Unfortunately, these types of devices have the typical graft distribution problem discussed above, in that they do not provide a path for bone graft to be inserted and fill in the space surrounding the cage or within the cage. They have other problems as well, including that the annulotomy must be large to accommodate a large enough cage for stability, and this large opening necessitates more trauma to the patient. Moreover, they can also create the additional problem of “backout”, in that they cannot expand laterally beyond the annulotomy to increase the lateral footprint of the cage relative to lateral dimension of the annulotomy. Since it takes several months for the fusion to occur to completion in a patient, the devices have plenty of time to work their way out of the space through the large annulotomy.
Scaffolding systems may also suffer a lack of stability and/and or a lack of a retention of structural components in a desired expansion configuration in the intervertebral space. As such, a multi-component scaffolding system, for example, can benefit from an improved design that adds stability through, for example, (i) enhancing the amount of contact between the scaffolding components upon expansion; and/or (ii) limiting the amount of expansion, or relative movement, that can occur between components upon expansion, or after expansion, in the intervertebral space. Such design considerations can, for example, address the problems of overexpansion of one component relative to another due to, for example, variable stresses that might occur in the intervertebral space upon expansion or after expansion, stresses which can result in at least partial failure of the scaffolding system in the intervertebral space.
Accordingly, and for at least the above reasons, those of skill in the art will appreciate bone graft distribution systems that facilitate an improved distribution of graft material throughout the intervertebral space. Such systems are provided herein, the systems configured to (i) effectively distribute bone graft material both from the system, and around the system, to improve the strength and integrity of a fusion; (ii) reduce or eliminate the problem of failures resulting from a poor bone graft distribution; (iii) have a small maximum dimension in a collapsed state for a low-profile insertion into the annulus in a minimally-invasive manner, whether using only a unilateral approach or a bilateral approach; (iv) laterally expand within the intervertebral space to avoid backout of the system through the annulotomy; (v) vertically expand for distraction of the intervertebral space; (vi) provide an expansion in the intervertebral space without contracting the system in length to maintain a large footprint and an anterior position adjacent to the inner, anterior annulus wall, distributing load over a larger area, anteriorly, against the endplates; (vii) and, incorporate a stabilizer for stabilizing and/or retaining support beams upon expansion of the scaffolding in an intervertebral disc space. | {
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Neutron radiography is a non-destructive testing process used for determining certain material characteristics. In its simplest terms, neutron radiography is accomplished by irradiating an object with neutrons and measuring the resulting flux of neutrons which pass through the object per unit area. Material variations and characteristics of the tested object may thereby be detected by observing variations in neutron flux through the object. Neutron radiography is most often accomplished using thermal neutrons, or those neutrons having an average kinetic energy of about twenty-five one thousandths electron volts (0.025 eV). Some applications of neutron radiography require the use of cold neutrons, or neutrons having a kinetic energy less than five one thousandths electron volts (0.005 eV). Other applications may require the use of epithermal neutrons, or neutrons having kinetic energies up to a few electron volts. Neutrons with any of these energy levels are usually produced by thermalizing, or "moderating", high energy neutrons (up to several MeV), known as fast neutrons, which are emitted by a neutron source. This moderation is accomplished by directing the fast neutrons through a moderating material. The thermalization process results in an energy spectrum of neutrons essentially in thermal equilibrium with the moderating material.
Several different types of fast neutron sources for radiography are used. For example, nuclear reactors are one source of neutrons which provide highly intense beams of neutrons for irradiating an object to be tested. For many important applications of neutron radiography, however, it is desirable to have a neutron source other than a nuclear reactor.
An alternative source of neutrons known in the prior art is a Van de Graff accelerator. It produces neutrons for irradiation by accelerating deuterons against a beryllium target to produce fast neutrons. The beryllium target is disposed in a chamber of moderator material appropriate for moderating, or thermalizing, the fast neutrons down to the desired neutron energy level for radiography. An example of such a device is discussed in U.S. Pat. No. 4,599,515 which issued to Whittemore.
Yet other sources of neutrons for radiography are radioisotopes. One such radioisotope is californium-252, which emits, by radioactive decay, approximately 10.sup.6 neutrons per second per microgram of californium. The seemingly large neutron flux produced by californium-252 and other radioisotopes, however, is still much less intense than the neutron flux produced by a nuclear reactor. It is, therefore, important to make optimum use of all available neutrons when using a radioisotope neutron source in order to obtain a good image with a minimum of exposure time. A neutron radiography device using a radioisotope as the neutron source may incorporate one or several design features to fulfill the requirement of optimum use of available neutrons. For example, as is well known in the art, neutron flux will vary throughout the radiography device. The radiography apparatus could be designed to establish a maximum thermal neutron flux at the imaging plane. One way of achieving this result is to dispose the radioisotope sources in a neutron moderator such that the imaging plane is exposed to the maximum thermal neutron flux in the moderating material. A second method of making optimum use of available neutrons is to shield the imaging plane from non-neutron radiation "noise". Such noise primarily consists of electromagnetic radiation, such as gamma rays produced by source radioisotope decay. The gamma rays, by irradiating the imaging plane, can thereby lower system photographic contrast. In the past, conventional radioisotope neutron radiography devices have provided poor shielding of gamma rays emerging directly from the radioisotopes. This is due, in part, to some of these prior devices disposing the neutron source in line-of-sight of the imaging plane, in an attempt to obtain maximum neutron flux. Unfortunately, such line-of-sight placement also results in a substantial amount of direct gamma irradiation of the imaging plane.
A third design technique to optimize the number of available neutrons in a radiograph is to establish a uniform neutron flux across the imaging plane by opening up the full neutron source plane as an optimum source of neutron flux. By establishing a substantially uniform neutron flux across the entire imaging plane, a greater area of the test object per exposure may be radiographed. Conventional designs for neutron radiography devices which use radioisotopes as the neutron source tend to produce a neutron flux which is not uniform across a relatively large imaging plane. This, in turn, either reduces the effective area of the test object which can be radiographed with each exposure, or results in lower photographic image density of those parts of the imaged object or objects near the boundaries of the imaging plane.
Accordingly, it is an object of the present invention to provide a neutron radiography deice which optimizes neutron flux across the imaging plane. It is a further object of the present invention to provide a neutron radiography device which produces a uniform neutron flux across the imaging plane. Still another object of the present invention is to provide a neutron radiography device which accomplishes the above while substantially shielding gamma rays from the imaging plane. Another object of the present invention is to provide a neutron radiography device that is durable, reliable, and cost-effective in its manufacture and use. | {
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This invention relates to an outboard motor and more particularly to an improved cowling construction for outboard motors.
As is well known, it is the normal practice to enclose the engine of an outboard motor within an outer protective cowling. The protective cowling serves several purposes, the prime of which are the protection of the engine and its associated components from the elements and to improve the appearance of the motor. Since the engine is substantially concealed and contained with the protective cowling, it is necessary to provide some arrangement wherein the inlet air may be delivered to the engine induction system through the cowling. The air inlet should be of such a nature that it does not substantially restrict the intake air flow, but, at the same time, it should prevent the entry of water from either rain or splashes from entering the engine induction system. In order to achieve these inconsistent functions, it has been proposed to provide a rear air inlet in the protective cowling and a tortuous air path from that inlet to the engine induction system. The tortuous air inlet path is designed so as to facilitate separation of water from the inlet air so the engine induction system and other engine components will be protected from water which may be drawn into the air inlet opening. However, the constructions of the type previously proposed for this purpose have provided such tortuous paths and restricted inlet openings that the efficiency of the engine induction system is deteriorated.
It is, therefore, a principal object of this invention to provide an improved cowling construction for an outboard motor.
It is another object of this invention to provide an improved air inlet system for the cowling of an outboard motor.
It is yet a further object of this invention to provide an outboard motor air inlet that will not significantly restrict air flow but which will at the same time prevent the ingress of water into the area around the engine.
As has been noted, certain prior art outboard motor cowlings provide rearwardly directed air inlets. Although such an arrangement may assist in preventing the ingress of water during forward travel of the boat, when the motor is tilted up and not in use it is possible for water to enter into the inlet opening and come into contact with the engine. For example, if the motor is tilted up when not in use and rain occurs, the rain can flow directly into the air inlet. Although a labyrinth or tortuous air path may be provided, the water can accumulate in the air inlet cavity provided in the outer cowling and enter into the engine area either when the engine is tilted up or when it is returned to its normal operating condition.
It is, therefore, a further object of this invention to provide a protective cowling for an outboard motor that will prevent the entry of water into the engine area under substantially all conditions.
It is a further object of this invention to provide a protective cowling arrangement for an outboard motor in which water is permitted to drain from the air inlet area regardless of the orientation of the motor.
The rearward facing air inlet of prior art protective cowlings has been defined in part by a recess in the rear portion of the main outer cowling member. This recess is covered by a cover plate and defines an air inlet cavity with the recess and an inlet to this cavity. When connecting the outer cowling members and cover plate together, it is important that the final construction provide a unitary appearing assembly and, nevertheless, one in which the air inlet function is efficiently and effectively provided.
It is, therefore, a further object of this invention to provide an improved cowling assembly for an outboard motor. | {
"pile_set_name": "USPTO Backgrounds"
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1. Technical Field of the Invention
This invention relates generally to wireless communication systems and more particularly to integrated circuits of transceivers operating within such systems.
2. Description of Related Art
Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), radio frequency identification (RFID), Enhanced Data rates for GSM Evolution (EDGE), General Packet Radio Service (GPRS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, RFID reader, RFID tag, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channels (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system or a particular RF frequency for some systems) and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the Internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the receiver is coupled to an antenna and includes a low noise amplifier, one or more intermediate frequency stages, a filtering stage, and a data recovery stage. The low noise amplifier receives inbound RF signals via the antenna and amplifies then. The one or more intermediate frequency stages mix the amplified RF signals with one or more local oscillations to convert the amplified RF signal into baseband signals or intermediate frequency (IF) signals. The filtering stage filters the baseband signals or the IF signals to attenuate unwanted out of band signals to produce filtered signals. The data recovery stage recovers raw data from the filtered signals in accordance with the particular wireless communication standard.
As is also known, the transmitter includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier. The data modulation stage converts raw data into baseband signals in accordance with a particular wireless communication standard. The one or more intermediate frequency stages mix the baseband signals with one or more local oscillations to produce RF signals. The power amplifier amplifies the RF signals prior to transmission via an antenna.
While transmitters generally include a data modulation stage, one or more IF stages, and a power amplifier, the particular implementation of these elements is dependent upon the data modulation scheme of the standard being supported by the transceiver. For example, if the baseband modulation scheme is Gaussian Minimum Shift Keying (GMSK), the data modulation stage functions to convert digital words into quadrature modulation symbols, which have a constant amplitude and varying phases. The IF stage includes a phase locked loop (PLL) that generates an oscillation at a desired RF frequency, which is modulated based on the varying phases produced by the data modulation stage. The phase modulated RF signal is then amplified by the power amplifier in accordance with a transmit power level setting to produce a phase modulated RF signal.
As another example, if the data modulation scheme is 8-PSK (phase shift keying), the data modulation stage functions to convert digital words into symbols having varying amplitudes and varying phases. The IF stage includes a phase locked loop (PLL) that generates an oscillation at a desired RF frequency, which is modulated based on the varying phases produced by the data modulation stage. The phase modulated RF signal is then amplified by the power amplifier in accordance with the varying amplitudes to produce a phase and amplitude modulated RF signal.
As the desire for wireless communication devices to support multiple standards continues, recent trends include the desire to integrate more functions on to a single chip. However, such desires have gone unrealized when it comes to implementing baseband and RF on the same chip for multiple wireless communication standards.
Therefore, a need exists for an integrated circuit (IC) that implements baseband and RF of multiple wireless communication standards on the same IC die. | {
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1. Field of the Invention
The invention relates to magnetic article surveillance systems, and coded markers for such systems, which are capable of generating and distinguishing among large numbers of codes.
2. Statement of Art
Article surveillance systems using soft magnetic materials and low frequency detection systems have been known since the Picard patent (Ser. No. 763,861) was issued in France in 1934. Picard discovered that when a piece of metal is subjected to a sinusoidally varying magnetic field, an induced voltage, characteristic of the metal composition, is produced in a pair of balanced coils in the vicinity of the applied field. Today, such systems utilize the harmonics produced by a marker of soft magnetic strip to detect the marker. Due to the nonlinear characteristics of such markers, groups of even and odd order harmonics can be produced simultaneously or individually. Odd order (1, 3, 5 . . . ) harmonics are produced by a symmetrical switching of the B/H loop. Even order harmonics (2, 4, 6 . . . ) are produced by a non-symmetrical switching condition, typically caused by a D.C. magnetic bias internal or external to the material.
The nonlinear characteristics of the soft magnetic material, while not commonly found, can be duplicated is some ferrous alloys by the presence of a magnetic bias. This results in the generation of even and odd order harmonics that duplicates the response of soft magnetic materials, such as permalloy and the metallic glass products. However, the use of more sensitive detection equipment can add to the probability of false alarms due to ferrous alloys.
Another limitation of the soft strip and low frequency system is that only a single bit of information is available during marker and system interaction. The marker is either in the detection zone, or not. The only other alternative is that the marker is, whether or not in the detection zone, deactivated. While this is not a disadvantage for systems used in theft control, it is an extreme limitation when used for monitoring the flow of a group of differing objects, or even persons, through the detection zone.
Those systems using coded devices for monitoring people and articles in a selected area are quite capable of a large number of codes. Card access systems are a good example. They generally combine a digital network and/or radio frequency circuit to transmit the code. However, these devices are too expensive to use either for theft control of low cost items or for inventory control in factories or stores. It is understood that encoded markers can be affixed to or otherwise carried by any article or person, animal, etc. The term "article" is used herein to encompass such possibilities.
This invention differs from the prior art in that the codes utilized are not duplicated by biased ferrous alloys, even accidentally. Further, the coded marker can be embodied in a single element device and can be programmed (code changed) by altering the geometry of or extent of a conductor surrounding a magnetic core. It is detectable at large distances and is not sensitive to spatial orientation within the system. The number of codes does not depend on the marker structure but on the phase resolution of the detection system and programming device.
The concept of this invention can best be appreciated in contrast to the teachings of specific and representative patents. The prior art can be broken down into the following classifications: (1) single element; (2) multiple element (3) biased (magnetized); and, (4) unbiased.
A bistable magnetic device is disclosed in U.S. Pat. No. 3,820,090-Wiegand. The marker is in the form of a wire, preferably with a magnetically "hard" magnetized outer shell (having a relatively high coercivity) and a moderately "soft" magnetic core (having a relatively low coercivity). The magnetized shell portion is operable for magnetizing the core portion in a first direction, the magnetization of the core portion is reversible by application of a separate magnetic field and the shell is operable to remagnetize the core portion in the first direction upon removal of the separate magnetic field. The device requires a fixed orientation to the interrogation field. The system can produce additional codes only by using multiple elements. Such devices are generally used for close proximity card access systems.
The device disclosed in U.S. Pat. No. 3,747,086-Peterson uses multiple elements to bias a soft magnetic strip. The marker comprises a plurality of ferromagnetic elements including a first element capable of generating a signal containing harmonics of an exciting oscillatory interrogating field and a seond element having a coercive force greater than the first element and capable of retaining a state of magnetization when exposed to the interrogation field, such that when so magnetized, a magnetic bias is imposed on the first element to prevent the generation of the harmonic signal. Four possibilities (codes) exist depending on which element is magnetized. However, these codes are easily reproduced in any biased, ferrous alloy. The system is neither unique nor reliable.
The system disclosed in U.S. Pat. No. 3,765,007-Elder uses markers of "n" number of elements with differing AC coercivities to produce "n" number of codes. When the elements are subjected to a periodically varying magnetic field, the magnetization of the elements reverses sequentially at equal intervals of time. Like Peterson, Elder's system is prone to false alarms from biased, ferrous alloys which inadvertently, and all to frequently, duplicate the code. Moreover, a plurality of magnetic field producing means must be used to cover all orientations of the coded elements (markers).
The system disclosed in U.S. Pat. No. 4,134,538-Lagard, et al. uses markers of "n" multiple elements or bands producing varying amplitudes as a code. Such magnetic bands are selectively divided at variable predetermined locations by cuts of variable predetermined extent, such that when in the detection zone, signals of varying amplitudes are produced. The marker must pass correctly oriented and in close proximity to the coils in the detection zone. It is primarily a device intended for access or inventory control and is expensive to produce.
This invention is based upon the discovery that when a suitable conductor, such as aluminum or copper, partially or totally encloses a core of soft magnetic material, the phase of the harmonics produced will be shifted (delayed in time). The amount of phase shift induced is controlled largely by the amount and resistivity of the conductor surrounding the magnetic material. It is feasible to shift any harmonic or groups of harmonics by any amount, through 360 degrees. However, some loss of harmonic amplitude is encountered as the conductor thickness increases and as the harmonic number increases.
The ability to control harmonic phase permits the generation of signals having a unique signature, apart from both ferrous alloys and soft magnetic materials. This avoids the accidental detections plaguing prior art systems as described above. In addition, a number of codes can be established according to the phase shift induced. The phase shift is not affected by a low level, external magnetic bias, in that odd order products are totally unaffected and even products shift by +/-180 degrees.
The system comprises an oscillator which provides phase locked signals to a transmitter/amplifier circuit and receiver/phase comparator circuit. Phase shifted harmonic generated by the marker are captured and amplified in the receiver. A comparison is made only of the phase of the received harmonics to the phase of the transmitted signal. Either one or more harmonics may be compared depending on the particular system use. A system used for theft control device requires a minimum code level but a maximum number of harmonic phase comparisons. A system used for inventory control would require a maximum number of codes but a minimum number of phase comparisons. Once the phase shift is compared and found to be correct (in the case of a theft system for example) an alarm is sounded. An inventory control system would have further processing equipment to send data to a cash register or a computer, to actuate a mechanical/electrical device or a combination thereof. | {
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The present invention relates generally to a high-power pulsing circuit and more particularly to a repetitive pulse inductive energy storage and transfer circuit for an electromagnetic launcher.
Electromagnetic launchers are generating considerable interest because their projectile launch velocities are not limited to the sonic velocity of an expanding gas, as in conventional guns. In the railgun, the simplest and most successful type of electromagnetic launcher, a projectile sliding between two parallel rails acts as a sliding switch or electrical short between them. By passing a large current down one rail, through the projectile (or a conducting sabot or plasma behind it), and back along the other rail, a large magnetic field is built up behind the projectile, accelerating it to a high velocity by the force of the current times the magnetic field. Projectile velocities over 10 kilometers per second can be obtained by this method.
Electromagnetic launchers of the railgun type have the problem that the launch process is inefficient. Even under the ideal conditions of constant-current drive and no dissipative losses, only one-half of the energy extracted from the power source is transferred to the projectile. The remainder goes into building up the magnetic field behind the projectile or, equivalently, into energizing the railgun inductance. If the energy stored in the inductance of the rails is not recovered after each launch operation, then it will be dissipated (in the rail resistance and in a muzzle blowout arc). Under these conditions, therefore, the best operational efficiency (projectile energy/power supply energy delivered) that repetitive railguns can achieve is 50 percent. Of course, dissipative losses in switches, the rail resistance, or a plasma arc behind the projectile only serve to reduce the operational efficiency below this limit.
One possibility for utilizing the inductively-stored rail energy is the breech crowbar circuit which uses a crowbar switch at the breech of the railgun to crowbar or short circuit the driving power supply when the projectile has reached some fraction of its launch velocity. Thereafter, the projectile is further accelerated by the expansion of the magnetic field trapped in the railgun behind the projectile. Unfortunately, the barrel length has to be doubled to convert one-half of the trapped magnetic energy to projectile kinetic energy and quadrupled to convert 75% of the trapped energy (assuming no dissipative losses). While technically feasible, the breech crowbar scheme results in a very large increase in railgun barrel length and never recovers all of the trapped energy.
High pulse power repetitive pulse inductive storage circuits have been disclosed in applications Ser. No. 617,653 and Ser. No. 617,658 both filed on June 5, 1984, and issued as U.S. Pat. No. 4,642,476 on Feb. 10, 1987, and U.S. Pat. No. 4,613,765 on Sept. 23, 1986, respectively. These applications illustrate some advantages of repetitive pulse indicative storage circuits and describe the type of switches that can be used therewith. These applications are incorporated by reference.
Therefore, it is an object of the present invention to provide a high-power energy transfer circuit with the capability to recover energy stored in the inductance of the load.
It is another object of the present invention to provide a repetitive energy transfer and recovery circuit.
It is another object of the present invention to provide an efficient energy transfer and recovery circuit using survivable switches.
It is still another object of the present invention to provide an energy transfer circuit for railgun electromagnetic launchers which can recover the energy from the load inductance without increasing the barrel length over that required for normal acceleration. | {
"pile_set_name": "USPTO Backgrounds"
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Barbecue grills have been popular for many years with backyard and patio chefs. These grills typically have been heated by charcoal briquettes or by fuel gas. In recent years, portable grills heated by a fuel gas source, such as a propane tank, have become increasingly popular. These gas grills combine the convenience of portability with the use and thermal efficiency of propane, which eliminates the need for lighter fluid, new charcoal at each use, and charcoal disposal.
Portable gas grills typically include a cart, with two or four wheels, that supports a cooking housing. The cooking housing typically consists of a firebox, a cover, and a burner near the bottom of the firebox. It also includes a grate for holding socalled "lava rocks" (pumice stone), a heat distribution plate, or an apparatus that shields the burner tubes from grease drippings and simultaneously vaporizes drippings falling on to the apparatus. That plate or apparatus is typically spaced above the burner in the firebox, and a metal wire cooking grid is positioned well above the plate or apparatus for holding the food to be cooked. Portable gas grills include a portable fuel tank supported by the cart, below the firebox. Features often found on portable grills include side burners for cooking or warming food; warming racks positioned above and to the rear of the cooking grid; rotisserie devices for cooking on a spit above the cooking surface; and condiment racks for holding spices, sauces, and other useful condiments.
Lava rock grates, heat distribution plates and vaporizing structures each act as barriers to the heat transfer from the gas burners at the bottom of the grill lower housing to the cooking grid. It is an object of the present invention to remove these structures, or any other structures, between the burner and the cooking surface and thereby increase heat transfer efficiency. The burner in the present invention is also placed substantially closer to the cooking surface than burners in the prior art. As a consequence of the burner's proximity to the cooking surface and the removal of heat barriers, the heating efficiency of the present invention is significantly increased.
It is another object of the invention to provide a burner shaped to vaporize grease, spread out the flame for even heat distribution, and allow grease to run off the tube without clogging the burner holes in the tube.
It is another object of the invention to provide burner tubes that are easy to insert into and remove from the firebox.
It is another object-of the invention to provide a structure for propagating flames from one burner tube to another burner tube parallel to the first burner tube that does not create a "hot spot" in the grill cooking surface.
Portable gas grills are typically constructed out of cast aluminum. One object of .the present invention is to provide an improved method of manufacture for the grill housing, cart, and burner, through the use of roll-forming technology. The use of roll-forming allows for the manufacturing and marketing of different-sized grills and grill parts without re-tooling of the manufacturing process.
It is another object of the invention to provide a cooking surface with crests and troughs, and apertures in the troughs, to optimize heat transfer and to allow for improved flow of grease drippings, and to contain flare-ups below the cooking surface.
It is another object of the invention to decrease the frequency of grease fires by the general placement of exhaust vents or apertures in the upper portion of the walls of the grease-catching structure located beneath the firebox.
It is another object of the invention to provide an improved rotisserie device for use with the barbecue grill described herein.
Other objects and advantages of the invention will become apparent to those skilled in the art by reference to the accompanying description and drawings. | {
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The present invention relates to a measurement system. In particular, the present invention relates to a capacitance-to-digital modulator for use with a capacitive differential pressure sensor.
A field transmitter is a device that is used to monitor the operation of an industrial process. The field transmitter includes a transducer that responds to a measured process variable with a sensing element and converts the variable to a standardized transmission signal that is a function of the measured variable. The term “process variable” refers to a physical or chemical state of matter or conversion of energy. Examples of process variables include pressure, temperature, flow, conductivity, and pH.
One such transmitter is described in U.S. Pat. No. 6,295,875 by Roger L. Frick and David A. Broden. This transmitter employs a capacitive sensor having a deflectable sensing diaphragm and three or more capacitor electrodes which form separate capacitive sensing elements with the diaphragm. Two of the capacitor elements are primary sensing capacitors that are arranged differentially so that the capacitances of the primary sensing capacitors charge oppositely in proportion to the process variable. The third and fourth capacitor elements are compensation capacitors that provide signals representing offset errors or hysteresis associated with the primary capacitors. As pressure is applied to one or both sides of the diaphragm, the diaphragm deflects. The deflection of the diaphragm can be detected by measuring a change in a ratio of electrical capacitance related to the deflection. This capacitance ratio is converted into a digital format using an analog-to-digital converter.
One particularly advantageous form of analog-to-digital converter uses a sigma-delta (or delta-sigma) modulator. The use of sigma-delta modulators in transmitters is described in U.S. Pat. No. 5,083,091 by Roger L. Frick and John P. Schulte; U.S. Pat. No. 6,140,952 by Michael Gaboury; U.S. Pat. No. 6,509,746 by Rongtai Wang; and U.S. Pat. No. 6,516,672 by Rongtai Wang.
In a transmitter having a sigma-delta modulator acting as a capacitance-to-digital (CD) converter, an excitation circuit provides charge packets to the capacitive sensor elements. The sensor elements are charged by an amount based on the capacitance value of that capacitive element. The charges are transferred to an integrator/amplifier of the sigma-delta modulator to produce a one-bit binary output which is a function of a capacitance ratio.
The basic function of the CD modulator is to convert the capacitance ratio into a PCM (pulse code modulation) signal. The capacitance ratio under measurement is defined as: η=(CX−CY)/(CX+CY), where CX and CY represent capacitance of two sensor capacitors with a common plate.
For a CD modulator using sigma-delta architecture, the actual process involves converting a charge ratio into a PCM signal. Under normal operating conditions, since the charge is proportional to the capacitance, the charge ratio is equal to the capacitance ratio.
However, this equivalent relation is not true under certain abnormal operating conditions. One such operating condition is overpressure in conjunction with a short circuit in one of the sensor capacitors. Due to the leakage caused by the short circuit, the charge that is transferred from the sensor capacitor may be very small. As a result of this, the digital reading provided by PCM signal is not equal to the capacitance ratio. Not only is the magnitude of the reading not correct, in many cases even the polarity of the reading is wrong. This kind of phenomena is called “fold-back anomaly”. There is a need for improved circuitry that eliminates the fold-back anomaly. | {
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This invention relates to drawer organizer systems in general, and in particular to an improved drawer organizer management system using R.F. drawer identification.
Drawer organizer systems are known and are used generally to store small items in drawers which are slidably mounted in a cabinet designed for this purpose. The cabinet is usually fixed to a wall or a support surface, such as a work bench. Each drawer typically has a drawer pull mounted on a front panel so that a user can slide the drawer outwardly from the cabinet and gain access to the contents of the drawer. Cabinets and drawers have been fabricated from both metal and plastic, with some drawer organizers using metal for both the cabinet and the drawers, others using plastic for both the cabinet and the drawers, and others using a metal cabinet and plastic drawers. The plastic materials used in the past have been either opaque or translucent.
Many types of items can be stored in a drawer organizer. Some examples are fasteners of several kinds, such as nuts, bolts, washers, sheet metal screws, and wood screws; grommets of various sizes; O-rings; electrical connectors; and small electronic components, such as diodes, resistors, and capacitors. Drawer organizers are found in homes, work shops and manufacturing facilities and have proven to be useful in a wide variety of situations requiring the organized storage of small items for future access.
A principal difficulty encountered with the use of drawer organizers lies in the manner of retrieving desired items from the collection of items stored in the several drawers in a given cabinet. In particular, retrieving the correct item requires identifying the contents of individual drawers until the correct drawer is found. In some applications, visual inspection through a transparent front drawer panel is the technique relied upon to identify the types of articles contained in that drawer. In other applications, small labels are adhered to the front panel of the drawers, with each label containing a brief description of the articles contained in that drawer. Both techniques are less than optimal. The visual inspection technique divulges only a minimum of subjective information about the contained articles. Similarly, the label technique is limited by the amount of space available on the label to describe the contained articles. Depending on the nature of the contained articles, the label technique cannot adequately distinguish the articles in one drawer from the articles in other drawers. For example, if the contained articles are resistors of different resistance values and power ratings, it is at best difficult to adequately distinguish among the several choices. The label technique also suffers from the disadvantage that the labels must be changed whenever the kinds of articles contained in a given drawer are changed. Both techniques are relatively inefficient in enabling quick identification of the correct drawer in applications having large collections of different types of articles. In general, the larger the number of drawers, the slower the access time to the contents of the desired drawer.
The invention comprises a drawer organizer management system which is devoid of the above-noted limitations and disadvantages, which can be implemented using any articles suitable for containment in an organizer drawer, and which greatly facilitates ready access to specific items contained in organizer drawers.
In a broadest aspect the invention comprises a drawer organizer management using r.f. identification of individual drawers in a cabinet. The system includes a cabinet having a structure including a rear wall for providing a plurality of drawer locations, the cabinet having a plurality of pairs of external terminals adapted to be coupled to an r.f signal generator for receiving r.f. signals from the generator, with each of the external terminal pairs being arranged preferably on the rear wall in a position corresponding to a different one of the drawer locations.
A plurality of drawers are each slidably mounted in a different one of the drawer locations between a closed position and an opened position. Each of the plurality of file drawers has a pair of electrically conductive drawer terminals adjacent the rear thereof and are adapted to engage a corresponding pair of the external terminals, a pair of electrical r.f. signal conductors coupled to the drawer terminals, and an r.f. circuit coupled to the pair of r.f. signal conductors. Each of the r.f. circuits has a crystal resonant at a specific frequency and a visible indicator activated whenever the associated crystal detects an r.f. signal at the specific frequency of that crystal. The resonant frequency of each of the crystals is different from the remaining ones of the crystals so that an r.f. signal of a specific frequency applied to the external input terminals of the cabinet causes only one of the plurality of crystals to resonate and only the visible indicator associated to that crystal to be activated.
Each of the drawers has a front panel, and the indicators are located on the front panel so as to provide a visible indication of a resonant crystal in the drawer when the drawers are closed. Each of the visible indicators preferably comprises an LED. Each of the drawers also has a rear panel, and the pair of electrically conductive drawer terminals is preferably mounted on the rear panel. Each of the drawers is further provided with a positive detent mechanism for promoting contact between the electrically conductive drawer terminals and the external terminals. Each of the drawers is also provided with a pair of positive contact elements, such as a pair of springs, for promoting contact between the electrically conductive drawer terminals and the external terminals
The system is used to locate the drawer containing a desired type of item in the following manner. A user enters the identity of a desired item in the system computer, either via a keyboard or by using a mouse to select an item from a list displayed on the computer monitor. In response, the computer performs a table-lookup from a set of frequencies which are uniquely associated to the items stored in the drawers. Once the corresponding frequency has been found, the computer instructs the r.f. signal generator to generate r.f. signals of the correct frequency. These r.f. signals are coupled to the individual cabinet drawers, and the r.f. circuit having the crystal of the correct frequency resonates, thereby illuminating the corresponding visible indicator on the drawer front panel. The user now knows which drawer contains the desired item.
The invention provides a low cost, effective and convenient technique for facilitating the location of specific items contained in a drawer organizer system. In addition, the invention eliminates, or substantially reduces the need for reliance on, the labelling practice currently followed in setting up drawer organizer systems. Moreover, the invention affords a flexibility in arranging drawer organizers hitherto unavailable. In particular, the identity of the items in any given drawer can be easily changed by modifying the description in the system computer. Also, additional drawers can be added to expand the inventory held in the system, and existing drawers can be deleted from the system by changing the information stored in the computer.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings. | {
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Sanding devices are used for sanding a variety of surfaces. Some forms of sanding devices are manufactured with an abrasive material permanently bonded to a base structure. In one example, this type of sanding device comprises abrasive particles adhered to a foam base. When the abrasive particles are worn or clogged, the entire sanding device is discarded.
In order to mitigate the cost of discarding such sanding devices, alternate variations are also available where the sanding device is configured to interchangeably receive sandpaper sheets. The sandpaper sheets are loaded and, after use, the worn sandpaper sheet is removed and a new sandpaper sheet is subsequently loaded. Such a sanding device is molded as a single unit and typically has an extension flexibly integrated on each end to provide an open slot on each end. This sanding device further includes a series of spikes with the slot for retaining the sandpaper. The sandpaper is loaded onto the spikes when the extension is flexed away to enlarge the slot. Once the sandpaper is properly positioned, the extension is released and the slot is closed. The two extensions typically oppose one another to retain the sandpaper in two locations. One example of a prior art sanding device is shown in FIGS. 1-3.
The extensions are typically integral to the sanding device and are formed by a molding process. Rubber is a common material used for the fabrication of these types of sanding devices. Unfortunately, the excessive bending of the extensions between their more open and closed positions on a continual basis causes fatigue of the connection and often results in the extension breaking off. It has also been observed that if the extensions are over flexed to an extreme position during a single use, breakage may occur. Once breakage has occurred, the sanding device cannot function as intended and is usually discarded.
Therefore, there is a need for sanding devices that overcome, alleviate, and/or mitigate one or more of the aforementioned and other drawbacks of prior art sanding devices. | {
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There are a number of processes described in the literature and patents for recycling NIMH batteries to recover the valuable nickel values contained in them as nickel metal grid, nickel plated foil, the nickel hydroxide in the cathode with some cobalt hydroxide and the nickel metal powder present in the anode as a nickel metal alloy with rare earth metals. Up to now the recovery processes have focused only on the nickel values which allowed for direct smelting of these batteries in furnaces as part of the feed for making high nickel alloys. The rare earth metals react under these conditions to form the rare earth oxides similar to how they are found in nature and end up in the molten oxide slag which is thrown away. More recently, processes have been described where these batteries are carefully melted and the slag volume and nature are controlled to end up with a richer rare earth slag more suitable for recovering the rare earths from the slag in the same way they are recovered by current production processes from rare ores. Another way that is being developed is the total solution of the isolated NIMH electrode materials to produce solutions of the nickel, cobalt and the rare-earth salt mixtures. These solutions are then processed by normal hydrometallurgical methods to separate the solution components into the nickel hydroxide (or carbonate), cobalt hydroxide (or carbonate) and the rare earth separated into a separate mixed rare earth component for processing on a standard rare earth oxide separation process line associated with rare earth ore processing. The reason for this change in the expansion of these recycle processes to recover the rare earth oxides is that the world supply of these oxides is 95% controlled by China and the use for rare earth compounds continues to expand. This has caused supply of rare earth to become tight and probably to remain so with the associated increase in the value of these materials.
The rare earths material are found in the NIMH battery in the unique hydrogen absorbing AB5 metal alloy anode (about 32% are earth metals primarily lanthanum-25%) powder which is the key anode material found in most NIMH batteries. There is a significant amount of energy and loss material in separating then converting a rare-earth ore to the purified rare earth compound mix (25% lanthanum). The correct rare earth oxide mix is converted to the highly reactive rare earth metal mixture (Misch metal) under vacuum and very high temperatures (>1400° C.) under vacuum. This Misch metal then must be mixed with the correct amount of nickel metal and re-melted in a vacuum induction furnace and then cooled rapidly and then ground to a −325 mesh powder under inert atmosphere due to its reactivity. The very hard alloy is difficult to grind. This is a very energy intensive and costly process.
The invention is more preferably used in a cell containing a negative electrode having hydrogen storage alloy materials of the so-called AB5-type, a common example of which is described in the basic formula MsNiAlxMn4Co3 and MsNi5(AlxMn4Co3)x wherein Ms represents a lanthanum-rich misch metal (REM), which includes various rare earth metals and wherein 2.5<r<5.0, 0<s<2.5, 0<t<0.5, and 0<u<0.5. Hydrogen absorbing alloys of this class (i.e., AB5) are disclosed, for instance, in U.S. Pat. Nos. 4,216,274 (Bruning et al) and 4,375,257 (Bruning, et al).
The typical AB2-type materials, as currently envisioned, are based on TiNi2 and typically have the basic atomic structure Ni—Ti—V—Cr—Zr—X—Y wherein X and Y can be other elements of various selection. The invention is more preferably used in a cell containing a negative electrode having hydrogen storage intermetallic alloy materials of the so-called AB5-type, a common example of which are described in the basic formula MmNirCosMntAlu, wherein Mm represents a lanthanum-rich misch metal, which includes various rare earth metals, and wherein 2.5<r<5.0, 0<s<2.5, 0<t<0.5, and 0<u<0.5 and MsNiAlxMn4CO3.
Negative electrode alloys used in NiMH batteries typically comprise La, Pr and Nd as rare earth elements and Zn, Mg and Ni. Cobalt, manganese and aluminum are common additives.
The components of the NIMH battery include nickel metal grid, Ni(OH)2, nickel coated iron, potassium hydroxide electrolyte, and most importantly a nickel metal alloy powder of up to 25-30% by weight. This alloy powder has been developed to absorb considerable hydrogen and is the source of the descriptor “nickel metal hydride” battery. Under charging conditions this nickel alloy absorbs significant amounts of hydrogen as the metal hydride is formed electrochemically. Under battery discharge conditions this absorbed hydrogen reacts electrochemically back to hydroxide and water providing the electrical current of the battery. The currently most well known nickel alloy used is termed AB5 which is an alloy consisting of one part misch metal (mostly lanthanum or REM) to five parts nickel on a mole basis—theoretically 32.1% (REM) on a weight basis. Therefore the naturally occurring rare earth oxide mixture is used to form the misch metal which avoids the expense of separating the rare earth oxides into the individual elements before reducing them to the mixed metal and not to the pure metal such as pure lanthanum metal. This metal mixture is used which is called misch metal. Therefore the AB5 alloy is an alloy of a mixture of lanthanum group metals and nickel with some cobalt and other metals added in small amounts for optimized hydrogen formation and storage. This AB5 component is the most expensive raw material cost for this battery. | {
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The subject invention relates generally to positioning systems and more particularly to improvements in a servo-control continuous path closed-loop position control of an object.
In the art of precision positioning systems to position a machine tool slide, for example, it has generally been the practice to utilize a rotary prime mover coupled to a ball nut/lead screw. Linear slide motion is obtained by attaching the ball nut to the machine slide while driving the lead screw through a gear box. The prime mover may take various rotary drive forms, such as servo motors, pulse motors or pneumatic drives. A numerical controller may be employed to generate position command signals for multiple axis coordinated continuous position control of a machine tool from part description data stored on punched tape or other storage media. Continuous-path-positioning as opposed to point-to-point positioning requires extremely precise control of the velocity on the object being positioned at all times.
Various advances in the art have been used to improve the tool-positioning accuracy in the above-described machining system. For example, the laser interferometer has been employed to monitor the slide movement and its output compared with the command signals to obtain a following error signal which is used to power the prime mover through a servo amplifier. A velocity feedback arrangement has been combined with the laser interferometer position feedback to improve position accuracy. Normally a rotary transducer, such as a tachometer generator, is attached to the lead screw to generate the velocity control feedback signal. Nevertheless, prior art continuous-path-position control systems were limited with respect to their prospective utility in many applications, especially diamond machining of mirror surface finishes of complex geometric configurations. For continuous-path-precision machining systems, the above-described systems cannot be controlled to obtain continuous-path following errors in the range required for precise surface finishes.
For a specific feed rate, the error signal will have two significant components: a steady state following error level and a transient error level riding the following error level. The small steady state error is required to reduce the effects of load disturbances while a small transient error is required for a good surface texture.
Large loop gains are generally necessary for the position and velocity loops in order to reduce the error signal. A conventional way for achieving this is to use a lag compensator in the forward path. In some cases, this signal compensator is not adequate, particularly in ultra-precision machining. A second lag compensator added to the outer loop may be used to further reduce the error signal. This arrangement, either the single inner loop lag compensator or the combination of inner and outer loop lag compensation, is effective for routine cutting speeds (i.e., 0.05 inch per minute and higher).
At low cutting speeds, however, even very low friction in the drive train will cause a sticking and then slipping effect. It is believed that the slow transient response of the lag compensator allows the error signal to reach several microinches before a large enough portion of the signal has reached the terminals of the motor to effect the change in position, thus causing the stick-slip movement of a tool holder on the axis slide, or the like. The result is a finish on the machined part that is inferior to that obtained at higher cutting speeds. However, slow cutting speeds cannot be avoided when preparing certain parts.
Therefore, there is a need for improvements in continuous-path-position control systems for precision, continuous-path contour machining which can be operated at very low velocities and yet obtain an acceptable surface finish by maintaining transient positioning errors for the individual machine slides to less than 3 microinches. | {
"pile_set_name": "USPTO Backgrounds"
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The use of fiber reinforced/resin matrix composite materials in the manufacture of articles and components in becoming increasingly widespread in a number of industries, including the aircraft industry. Such composite materials include, for example, graphite fiber reinforced/epoxy resin matrix materials and glass fiber reinforced/polyimide resin matrix materials. In a common manufacturing procedure for producing articles and components from composite materials, a plurality of layers of the material are held onto a mold, and the mold with the lay-up thereon is placed in an autoclave to cure the resin matrix. During the curing process, the lay-up is covered by a vacuum pressure bag which transmits the autoclave pressure uniformly over the surface of the lay-up. The uniform pressure produces a high quality finished article or component and is particularly important in the manufacture of aircraft parts which must meet stringent tolerance limitations and/or structural strength requirements. In preparation for the curing procedure, a vacuum probe is positioned under the bag and is connected to a vacuum line. A vacuum is applied through the line and the probe is evacuate air between the bag and the lay-up. This urges the bag against the lay-up so that the desired uniform pressure will be achieved.
A number of problems have arisen in connection with the use of conventional vacuum probes. A major problem is that conventional vacuum probe structures do not provide a sufficiently reliable seal between the bag and the probe around the opening in the bag through which the probe extends. In a commonly used type of vacuum probe, the bag and an annular sealing gasket are clamped between two probe body parts. During the clamping procedure, the body parts are twisted relative to each other. This relative twisting tends to cause the bag to wrinkle or bunch and thereby prevent a reliable seal between the bag and the probe. Since the sealing surfaces are not visible, the presence of wrinkling or bunching cannot be detected and the quality of the seal cannot be inspected visually. If the seal is lost during the curing process, the entire lay-up must be discarded. The discarding of lay-ups adds significantly to the overall cost of producing the parts.
Conventional probes are relatively difficult and time consuming to use. They include a plurality of parts which must be assembled each time the probe is used. The parts can become separated from each other between uses. Therefore, even more time may be required to locate the parts before the probe can be assembled for use. Conventional probes are also relatively expensive to manufacture because of the plurality of parts, the relatively complex structure, and the need to machine the sealing surfaces. In addition, although excess resin from the lay-up is usually absorbed by a breather layer positioned between the bag and the lay-up and an extra pad of breather material is conventionally positioned under the probe, resin from the lay-up can get into the probe. The resin can foul the screw connections of the probe and thereby necessitate either an expensive cleaning procedure or the discarding of the entire probe. All of these factors add to the overall cost of manufacturing the parts.
Still another problem associated with the conventional vacuum probe design is that the entire vacuum line quick connect/disconnect fitting is positioned above the sealing surfaces, and therefore, the probe has a high profile. Vacuum hoses are heavy and must stretch over a long distance during the curing procedure. The relatively high probe profile creates relatively high leverage tending to tip the probe over during the curing process. A tipped probe can mar the surface of the lay-up and create pressure voids. This ruins the lay-up so that it must be discarded.
One approach to solving the problem of unreliable seals is to modify the basic two-part body and gasket probe structure described above. Examples of modifications that improve seal reliability are providing a pressure plate and lock ring to seal against the gasket, and providing concentric seal ridges on the probe top. In the latter example, the ridges are machined into the probe top and seal into the gasket to allow it to slide over the bag. Another type of two-part probe body developed by the assignee of the applicant is the subject matter of a copending U.S. patent application Ser. No. 06/901,855, filed Aug. 29, 1986, in the name of Matin et al. and entitled "Non-Metallic Vacuum Probe". In the probe disclosed in that application, a bearing washing is positioned adjacent to the gasket to avoid twisting of the bag upon assembly of the probe. The two parts of the probe body are tightened together by twisting the upper body part. The body parts engage each other by a ramp and lug arrangement. The upper body part extends down through a central opening in the lower body part and has a center passageway that borders on and communicates with an indentation on the bottom surface of the lower body part.
Vacuum probe arrangements used in the manufacture or repair of composite material parts are disclosed in U.S. Pat. No. 3,666,600, granted May 30, 1972, to S. Y. Yoshino; and U.S. Pat. No. 4,554,036, granted Nov. 19, 1985, to C. M. Newton, U.S. Pat. No. 2,411,743, granted Nov. 26, 1946, to H. G. Morner discloses a vacuum connection on a bag used in molding plastic-bonded sheet material, such as plywood. Apparatus for evacuating bags of food for home freezing is disclosed in U.S. Pat. No. 4,018,253, granted Apr. 19, 1977, to S. I. Kaufman. The open end of the bag is pulled through a hollow retainer and is sealed between the retainer and a cap to which an evacuation tube is connected. U.S. Pat. No. 4,417,638, granted Nov. 29, 1983, to B. F. Harvey, discloses a self-sealing elastomeric grommet for the rigid portion of an air pallet which has a bayonet connection to an air supply nozzle.
Molding apparatus in which the edge of an internal pressure bag around the opening in the bag is positioned in a groove or clamped is disclosed in U.S. Pat. No. 54,204, granted Apr. 24, 1866, to J. L. Presbrey; U.S. Pat. No. 3,137,898, granted June 23, 1964, to E. E. Geringer; U.S. Pat. No. 3,610,563, granted Oct. 5, 1971, to P. E. Allen; and U.S. Pat. No. 3,674,394, granted July 4, 1972, to A. J. Wiltshire. In the Geringer and Allen apparatus, fibrous material is positioned between the bag and the mold, and air is driven out of the material through a vent by the introduction of resin. In the Wiltshire apparatus, a sealing ring is positioned around the circumference of a sliding core of the air supply fitting between the material being molded and the mold. The core is driven outwardly to a final molding position by pressure supplied to the bag. In this position, the sealing ring is received in a sealing ring seat provided between the counterbore in which the fitting slides and the inner mold surface. The sealing ring prevents resin from entering the counterbore and fouling the sliding surface of the core.
Other types of connections between a pressure bag and an air supply fitting are shown in U.S. Pat. No. 1,784,817, granted Dec. 16, 1930, to A. E. Bronson; and U.S. Pat. No. 2,999,272, granted Sept. 12, 1961, to E. P. Warnken. Molding apparatus in which the outer and/or inner periphery of a pressure diaphragm is clamped is disclosed in U.S. Pat. No. 286,693, granted Oct. 16, 1883, to J. Fried; and U.S. Pat. No. 2,962,757, granted Dec. 6, 1960, to C. O. Slemmons et al. Fried also discloses an air supply hose coupling to a chamber above the diaphragm. In the Slemmons et al. apparatus, air is exhausted from the space between the upper mold portion and the workpiece and from the space between the workpiece and the diaphragm. A diaphragm or gasket-like member with peripheral edge portions that are received in a groove or are clamped are disclosed in U.S. Pat. No. 2,322,043, granted June 15, 1943, to J. C. McCune; U.S. Pat. No. 2,944,523, granted July 12, 1960, to F. A. Werstein; U.S. Pat. No. 3,187,590, granted June 8, 1965, to J. E. Duggan; and U.S. Pat. No. 3,410,144, granted Nov. 12, 1968, to J. L. Noz et al. Grommet-like annular fittings clamped to sheet material are disclosed in U.S. Pat. No. 4,626,122, granted Dec. 2, 1986, to B. Harrison et al.; and French Pat. No. 1,194,397, published Nov. 9, 1959, in the name of R. Discry.
The above-cited patents and the prior art that is disclosed and/or cited therein should be studied for the purpose of putting the present invention into proper perspective relative to the prior art. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates to autoregulating electric heaters and methods of using same, and more particularly, to a small ferromagnetic autoregulating electric heater that may be temporarily disposed about a part to be heated or soldered. The heater may be integrated as a permanent part of the structure or removed for subsequent repetitive uses after each heating application is completed.
In the U.S. Pat. No. 4,256,945 of Carter and Krumme, there is described an autoregulating electric heater having a laminated structure; one lamina of which has high magnetic permeability and high resistance and another lamina of which is non-magnetic and has a low resistance (such as copper) in electrical contact, and therefore, thermal contact with the first lamina. This structure is adapted to be connected across a constant current, a.c. source such that the layers are in a sense in parallel across the source.
Due to skin effect, the current is initially confined to the high magnetic permeability, high resistance layer so that P=KR.sub.1 where P is power, K is I.sup.2 which is a constant, and R is the effective resistance of the permeable material at high current concentrations. The dissipation of power heats the layer until it approaches its Curie temperature. The permeability of the lamina decreases towards the level of the second layer, copper for instance, at about its Curie temperature. The current is no longer confined to the high resistivity first lamina by the magnetic properties of the first lamina, and spreads into the copper layer; the resistance to the current drops materially, the power consumed, P=KR.sub.2 where R.sub.2 <<R.sub.1 is greatly reduced and the heating effect is reduced to a level that maintains the device at or near the Curie temperature. The device thus thermally autoregulates over a narrow temperature range about the Curie temperature.
The current source employed in the aforesaid patent is typically a high frequency source, for instance, 8 to 20 MHz to insure that the current is confined to the thin, high resistivity, magnetic layer until the Curie temperature of the magnetic material is attained. Specifically, the maximum regulation is achieved when the thickness of the magnetic layer is of the order of one skin depth at the frequency of operation. Under these circumstances, the maximum change in effective resistance of the structure is achieved at or about the Curie temperature. This fact can be demonstrated by reference to the equation for skin depth in a monolithic, i.e., non-laminar magnetic structure: ##EQU1## where 29 is the resistivity of the material in ohm-cms, .mu. is relative magnetic permeability and f is frequency of the current. The field falls off in accordance with e.sup.-x where x is thickness/skin depth. Accordingly, in a monolithic structure, by calculation, 63.2% of the current is confined to one skin depth in the high mu material. In the region of the Curie temperature, where .mu.=1, the current spreads into a region S.D.=5030 ##EQU2## If mu was originally equal to 200 (200-1000 being common), the skin depth in the region at the Curie temperature increases by the square root of 200; i.e., the skin depth in the monolithic structure is now 14.14 times greater than with .mu.=200.
The same type of reasoning concerning the skin effect may be applied to the two layer laminar structure in the aforesaid patent. Below the Curie temperature, the majority of the current flows in the magnetic layer when the thickness of this layer is nominally one skin depth. In the region of the Curie temperature, the majority of the current now flows in the copper and the resistance drops dramatically. If the thickness of this high mu material were greater than two skin depths, the percentage change of current flowing in the high conductivity copper would be less and the resistivity change would not be as dramatic. Similarly, if the thickness of the high mu material were materially less than one skin depth, the percentage of current flowing in the high resistivity material at a temperature less than the Curie temperature would be less so that the change of resistance at the Curie temperature would again not be as dramatic. The region of 1.0 to perhaps 1.8 skin depths of high mu material is preferred.
An exact relationship for the two layer case is quite complex. The basic mathematical formulas for surface impedance from which expressions can be obtained for the ratio of the maximum resistance, R.sub.max, below the Curie temperature, to the minimum resistance, R.sub.min, above the Curie temperature, are given in Section 5.19, pp. 298-303 of the standard reference, "Fields and Waves in Communications. Electronics," 3rd Edition, by S. Ramo, J. R. Winnery, and T. VanDuzer, published by John Wiley and Sons, New York, 1965. Although the theory described in the above reference is precise only for the case of flat layers, it is still accurate enough for all practical applications in which the skin depth is substantially less than the radius of curvature.
Difficulty may arise in such devices when the Curie temperature is achieved due to spread of the current and/or magnetic flux into adjacent regions outside of the device, particularly if the device is located close to sensitive electrical components.
In copending patent application of Carter and Krumme, Ser No. 243,777, filed Mar. 16, 1981, a continuation-in-part application of the application from which the aforesaid patent matured, there is described a mechanism for preventing the high frequency field generated in the heated device from radiating into the regions adjacent the device. This effect is accomplished by insuring that the copper or other material of high conductivity is sufficiently thick, several skin depths at the frequency of the source, to prevent such radiation and electrical field activity. This feature is important in many applications of the device such as a soldering iron where electromagnetic fields may induce relatively large currents in sensitive circuit components which may destroy such components.
As indicated above, the magnetic field in a simple, single layer, i.e., monolithic structure, falls off as e.sup.-x so that at three skin depths, the field is 4.9% of maximum, at five skin depths, it is 0.67%, and at ten skin depths, the field is 0.005% of maximum. For some uses, thicknesses of three skin depths are satisfactory although at least five are preferred in most cases, ten or more may be required with some highly sensitive devices in the vicinity of large heating currents.
The devices of the patent and aforesaid application are operative for their intended purposes when connected to a suitable supply, but a drawback is the cost of the high frequency power supply. Where only a very low field may be permitted to radiate from the device, the frequency of the source is preferably maintained quite high, for instance, in the megahertz region, to be able to employ copper or other non-magnetic material having reasonable thicknesses.
In accordance with the invention of co-pending application of John F. Krumme, Ser. No. 543,443, filed Oct. 25, 1983, a continuation in part of Ser. No. 430,317 , filed Sept. 30, 1982, now abandoned; both said applications being entitled "Autoregulating Electrically Shielded Heater", a relatively low frequency constant current source may be employed as a result of fabricating the normally non-magnetic, low resistivity layer from a high permeability, high Curie temperature material. Thus, the device comprises a high permeability, high resistivity first layer adjacent the current return path and a high permeability, preferably low resistivity second layer remote from the return path; the second layer having a higher Curie temperature than the first-mentioned layer.
As used herein, the term "high magnetic permeability" refers to materials having permeabilities greater than para-magnetic materials, i.e., ferromagnetic materials, although permeabilities of 100 or more are preferred for most applications.
The theory of operation underlying the invention of the aforesaid application filed on Sept. 30, 1982 is that by using a high permeability, high Curie temperature material as the low resistivity layer, the skin depth of the current in this second layer is such as to confine the current to a quite thin layer even at low frequencies thereby essentially insulating the outer surfaces electrically and magnetically but not thermally with a low resistivity layer of manageable thickness. The second layer is preferably formed of a low resistivity material, but this is not essential.
An example of a device employing two high mu laminae utilizes a layer of Alloy 42 having a resistivity of about 70-80 micro-ohms-cm, a permeability about 200, and a Curie temperature of approximately 300.degree. centigrade. A second layer is formed of carbon steel having a resistivity of about 10 micro-ohms-cm, a permeability of 1000, and a Curie temperature of about 760.degree. centigrade. The skin depths, using a 60 Hz supply are 0.1" for Alloy 42 and 0.025" for carbon steel. An example of a practical 60 Hz heater based on the above, may employ a coaxial heater consisting of a 0.25 inch diameter cylindrical or tubular copper conductor (the "return" conductor), a thin layer (perhaps 0.002 in thickness) of insulation, followed by the temperature sensitive magnetic alloy having a permeability of 400 and a thickness of 0.1 inch, and finally an outer jacket of steel having a permeability of 1000 and a thickness of 0.1 inch. The overall heater diameter would be 0.65 inch. If the heater is used in a situation requiring 5 watts per foot of heater length for instance, for protection of a liquid against freezing, the total length of the heater is 1000 feet, the resistance of the heater will be 1.96 ohms. The current will be 50 amperes, and the voltage at the generator end will be 140 volts at temperatures somewhat below the Curie temperature of the temperature sensitive magnetic alloy on the inside of the outer pipe. If there were substantial changes in the electrical resistance due to variations of the thermal load, the required voltage must vary in order to maintain constant current. Such a supply provides current at costs considerably less than a constant current supply at 8 to 20 MHz.
The power regulation ratios (AR) in such a device; 2:1 to 4:1, are not as high as with the device of the patent with a resistivity difference of about 10:1, but the AR difference may be reduced by using materials of higher and lower resistivities for the low Curie temperature and high Curie temperature materials, respectively. Also, a high mu, relatively low resistivity material such as iron or low carbon steel may be employed to further increase the power regulation ratio.
In accordance with the invention of copending patent application Ser. No. 445,862 of John F. Krumme filed on Dec. 1, 1982, autoregulation power ratios of 6:1 to 7:1 are attained while retaining the ability to utilize low frequency supplies without producing unacceptable levels of field radiation.
The objects of the invention are achieved by providing a region of high conductivity at the interface of the two members having high permeability as set forth in the Krumme application, Ser. No. 543,443, filed Oct. 25, 1983.
The material in the interface region may be copper, for instance, or other highly conductive material. The material may appear as a separate layer, a sandwich of magnetic, nonmagnetic and magnetic material or may be bonded to the high and/or low Curie temperature, ferromagnetic layers at the interface to provide a low resistivity, interface region.
Typical thicknesses of the sandwich construction for 1 KHz are 0.03" for both the low and high Curie temperature ferromagnetic materials, respectively, and 0.010 inch for the copper layer.
In operation, as the Curie temperature of the first layer is approached and its permeability rapidly decreases, the current spreads into the copper layer and into the second magnetic layer. The total resistance of the structure, due to the presence of the copper, drops dramatically providing a high autoregulating ratio. Also, most of the current is confined to the copper layer and only a small percentage penetrates into the second magnetic layer. In consequence, this latter layer need be only 3 to 5 skin depths thick to effect virtually complete shielding of the device. Thus, the object of a large autoregulating power ratio in a relatively small device using a low frequency source is achieved. By a low frequency is meant a source in the range of 50 Hz to 10,000 Hz although 50 to 8000 Hz is fully adequate.
With autoregulating ratios of 6:1 and 7:1, the heating variations below and above Curie temperature are quite large so that the apparatus may respond rapidly to thermal load variations and thus maintain accurate temperature regulation in a small device operating at low frequency.
In all of the above cases, the autoregulating heater structures are rigid and either constitute all or part of the device to be heated, i.e., the work piece, and becomes of necessity, a part of the final structure. The rigidity of the prior devices and the fact that the devices are, of necessity, part of the work, prevents their use in certain specialized areas. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention generally relates to a bicycle shift operating device. More specifically, the present invention relates to a bicycle shift operating device, which has a shift operating member that is relatively easy to move, yet is reliably retained in the desired shift position.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. Specifically, the bicycle shifting mechanisms or shift operating devices have been extensively redesigned.
The bicycle shifting mechanisms are parts of the bicycle transmission. The bicycle transmission typically includes front and rear shifting mechanisms designed to operate front and rear derailleurs to move the front and rear derailleurs laterally over a plurality of front and rear sprockets, respectively. The front and rear sprockets are usually coupled to the front crank and the rear wheel, respectively, such that the pedaling force from the rider is transferred to the rear wheel via the chain. Depending on the position of the chain on the front and rear sprockets, a variety of gear ratios can be provided.
In the past, shifting mechanisms or devices have been utilized that include one or more levers that are pivoted in order to wind and unwind an inner wire of a control cable. Alternatively, rotating hand grips have also been utilized to wind and unwind the inner wire of the control cable. Two shifting mechanisms are typically provided on multi-speed bicycles. Typically, one shifting mechanism is a front shifting mechanism, while the other shifting mechanism is a rear shifting mechanism. Each shifting mechanism usually has one shift cable coupled thereto that includes an inner wire. The wires of the front and rear shifting mechanisms are coupled to the front and rear derailleurs to shift the chain over the various front and rear sprockets, respectively. While these prior shifting devices work well, the prior shift levers do not always operate as well as desired by some riders and/or these prior shifting devices can be relatively complicated and expensive to manufacture and assemble.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle shift operating device. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates to severing and sealing thermoplastic material and, more particularly, to apparatus for using a hot wire to sever a plurality of plies of the thermoplastic material and sealing the severed margins thereof to form bags or similar containers.
In the process of manufacturing thermoplastic bags or other containers, a continuous web of the thermoplastic material is supplied from which individual bags are severed. The severed margins are sealed simultaneously to form the side seams of the bag. Typically, a hot-wire is used to sever and seal the thermoplastic material. The wire is formed of a metal alloy and may have a generally circular, elliptical, or rectangular cross-section and is usually heated to a temperature above about 1000.degree. F. to sever and seal the thermoplastic material, such as a polyethylene resin.
A significant problem with using a hot-wire element is that the heat from the wire causes gaseous polymer degradation products such as aldehydes to form during the severing and sealing operation. Some of these gaseous degradation products become entrapped on the surface or in the bags which are formed. The presence of such gaseous degradation products can produce an unpleasant odor and impart an off-taste to foods later stored in the bag. Past approaches to the problem have focused on accelerating the dissipation of the degradation products from the bag after the bag has been formed, rather than on reducing their creation during bag formation. For example, fans have been used to ventilate the bags while moving along the assembly line after formation and while being packaged into cases. Inventory hold-times have been established to allow time for the degradation products to dissipate from the bags while being stored. Additionally, the bags sometimes are stored in curing rooms heated to above 115.degree. F. to reduce the inventory holding-times.
Nevertheless, odor and taste problems associated with severing and sealing with a hot wire can be a serious problem. Accordingly, there is a need for apparatus that alleviates the odor and taste problems associated with using a hot wire to sever and seal thermoplastic material. | {
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The present invention is a process for the hydrogenation of chlorosilanes. The process comprises contacting a chlorosilane with aluminum and a hydrogen source selected from a group consisting of hydrogen gas and gaseous hydrogen chloride in the presence of a catalyst. The catalyst is selected from a group consisting of copper and copper compounds, tin and tin compounds, zinc and zinc compounds, and mixtures thereof.
Industrially significant methods for producing hydrosilanes involve, for example, the reaction of a halosilane with a metal hydride in the presence of a solvent as described in Kirk and Othmer, Encyclopedia of Chemical Technology; The Interscience Group, New York, N.Y, Vol. 12, p. 368, 1978. The preferred metal hydride reagents are LiAlH.sub.4 and NaAlH.sub.4. The reaction is reported to proceed quantatively at low system pressure and temperature. However, metal hydride reagents offer significant processing disadvantages. First, they are highly reactive and may oxidize exothermically to release explosive concentrations of hydrogen gas. Because of this, hydrogenation reactions with these reagents are typically carried out in solvents. The use of solvents presents a second disadvantage in that the solvent must be separated from the product. If solvents are not used, the metal may be stabilized by replacing a portion of the metal hydride ligands with bulky organic substituents. While this eliminates the solvent, it necessarily reduces the equivalent hydrogenation potential for the metal hydrides.
Non-metal hydride, non-solvent systems for hydrogenating halosilanes have also been reported. Hurd, U.S. Pat. No. 2,406,605, issued Aug. 27, 1946, disclosed the reaction of certain halosilanes with hydrogen or a hydrogen halide at an elevated temperature with a metal selected from a group consisting of aluminum, magnesium, and zinc. At temperatures of 400.degree. C. to 500.degree. C. and atmospheric pressure, Hurd determined that SiCl.sub.4 and MeSiCl.sub.3 could be reacted to SiHCl.sub.3 and MeHSiCl.sub.2 respectively. Hurd reported that the reaction of Me.sub.2 SiCl.sub.2 was generally unsuccessful, even at 500.degree. C.
Hatcher, U.S. Pat. No. 2,458,703, issued Jan. 11, 1949, reported a method of hydrogenating halosilanes using silicon as a chloride acceptor in a continuous high-pressure system. Hatcher reported that the silicon could reduce a halosilane in a hydrogen atmosphere when AlCl.sub.3 or AlBr.sub.3 was present.
Wagner et al., U.S. Pat. No. 2,595,620, issued May 6, 1952, reported that silicon could be used to reduce a chlorosilane with hydrogen at temperatures above about 400.degree. C. and the AlCl.sub.2 or AlBr.sub.3 required by Hatcher, supra, was not necessary.
Muetterties, U.S. Pat. No. 3,057,686, issued Oct. 9, 1962, reported a hydrogenation process where a halosilane was reacted with hydrogen and activated aluminum metal at superatmospheric pressure. Muetterties described the activated aluminum as a metal having an essentially oxygen free surface. The groups of compositions suitable for activating the aluminum as described by Muetterties were (1) metal hydrides, (2) mixtures of iodine and an alkyl halide in which the halogen has an atomic number of at least 17, and (3) trialkyl aluminum compounds.
Jenkner, U.S. Pat. No. 3,100,788, issued Aug. 13, 1963, reported a process for hydrogenation of halosilanes with hydrogen gas using sodium metal as the halogen receptor.
The present invention is a process for the hydrogenation of chlorosilane by a hydrogen source selected from a group consisting of hydrogen gas and gaseous hydrogen chloride. The process uses aluminum as the halogen receptor. The process does not require a solvent and can be run at near atmospheric pressure. The process employs a catalyst selected from a group consisting of copper and copper compounds, tin and tin compounds, zinc and zinc compounds, and mixtures thereof. Under the described process conditions, the catalyst provides for increased formation of silicon hydrogen bonds and increased chlorosilane conversion, when compared to the use of aluminum without catalyst. The catalyst also allows the process to be run at a lower temperature than that used for similar uncatalyzed processes.
Hydrosilanes prepared by the present process are useful intermediates in the formation, for example, of silicone polymers, elastomers, and resins. | {
"pile_set_name": "USPTO Backgrounds"
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Vehicle fueling service stations in some regions of the United States, i.e. those regions where only Phase I (i.e. non-Phase II) vapor recovery is mandated, and in many other countries, operate with limited or no restrictions on release of fuel vapors into the environment, e.g. including fuel vapors generated by evaporation of liquid fuel into the ullage space of vehicle and underground storage tanks (“UST”), and then displaced from the tank by entering liquid fuel during filling. This loss of fuel in its vapor state is recognized as a detriment to the environment. Over a period of fueling operations, it can also represent a substantial loss of product and potential profit to the service station owner and operator. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention generally relates to prevention of cross connections by residential users between a public source of drinking water where quality of the water is regularly monitored and maintained and a private source of water of questionable quality, such as from a domestic water well, where monitoring and maintenance of quality are lacking. More particularly, the present invention is concerned with an apparatus used for testing the condition of an end user's water distribution system, particularly, to test the condition of a one-way flow control valve and to detect the presence of cross connections.
2. Description of the Prior Art
Legislation passed by the Federal Government regarding protection of the public sources of drinking water addresses the problem of cross connections between public water supplies and any other questionable sources at the sites of end users in an attempt to eliminate sources of contamination of public drinking water supplies. Manufactures have designed devices to prevent cross connections from occurring. For example, a single one-way flow control, or check, valve is typically installed on a user's water meter setter to prevent backflow of water to the public water supply from a private water source through a connection with the residential water distribution system downstream of the water meter setter.
The employment of an one-way flow control valve is an effective solution to the prevention of contamination should there be such cross connections present as long as the flow control valve functions as it is intended so as to only allow one-way flow from the public water supply to the residential water supply plumbing and not vice versa. However, as with any mechanical device, flow control valves can develop backflow leakage after prolonged periods of use.
Consequently, a need exists for ways and means to not only test for and detect the presence of cross connections but also to test the condition of flow control valves meant to prevent backflow at the location of a users' water meter setter. | {
"pile_set_name": "USPTO Backgrounds"
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Modern storage systems typically include multiple standalone storage devices that are passive and whose performance characteristics are fixed in general once manufacturing is complete. A processor (e.g., RAID controller) executing software (firmware) is necessary to add intelligence to make the collection of unintelligent storage devices work as a unit. Because storage devices, such as solid state drives (SSDs), may be also controlled through the software or firmware, efforts have been made to control operating characteristics of a solid state drive according to the use environment.
The traditional approaches for satisfying user qualification tests require a manufacturer to provide last minute engineering processes to customize the storage devices for each customer. Customers typically wish to recalibrate their software systems whenever new models of storage devices are adopted because the characteristics of the storage devices are widely heterogeneous. However, the assumptions for one storage device are often not valid with another device. Consequently, traditional customization approaches are not sustainable in part because the manufacturer's engineering cost increases with the number of storage devices and customers requiring customization.
Therefore, a framework that enables an easy reconfiguration of storage systems on the behalf of customers is crucial. For instance, solid state disk (SSD) optimization software, such as Magician™ by Samsung, tunes performance of SSDs for a customer's system. However, customers have very limited optimization options, the optimization metrics are device-oriented in contrast to user-oriented, and the optimization is not controlled or quantifiable. In addition, storage device characteristics can change over time due to the degradation of the storage media such as wearing and fatigue. This can violate the initial assumption that the customer had, which cannot be perceived easily until malfunctions happen at the user level.
Another type of reconfigurable storage device process allows a customer to select individual features to configure a storage device. In this approach, instead of adjusting a customer's system to a new storage device, a reconfigurable storage device allows the customer to adjust the storage devices to their systems, which simplifies the maintenance and upgrade process.
Although reconfigurable storage devices can provide more flexibility in performance optimization and allow the customers to do customization, several challenges remain. One challenge is that the recalibration process constitutes a combinatory problem whose complexity increases exponentially with the number of features of the storage device to customize. In other words, current approaches do not provide systematic configuration method for feature selection. For example, if a customer changes the value of three features, it may be difficult for the customer to determine what effect the combination of features will be on the performance of the storage device.
A related challenge is that the selection of features by the customer is accomplished through a software user interface in which the customer selects the features manually. Manual selection of features without a systematic configuration method or performance guideline results is essentially a trial and error process.
Finally, the conventional reconfiguration process does not address the effects of storage device characteristics changing over time due to the degradation of the storage media. Such changes can render the original selection of features for a particular use environment no longer valid.
Accordingly, the trend of software-defined storage (SDS) in which storage resources required by an application can be defined by software and provisioned automatically requires an improved reconfigurable storage process that is more flexible. | {
"pile_set_name": "USPTO Backgrounds"
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Golf is becoming a more and more popular sport. Driving ranges are often used as a practice area for many golfers. Most driving ranges use a simulated grass mat having a rubber tee for supporting a golf ball in a teed position. As a result of continuous use, even these rubber tees become damaged and incapable of supporting a golf ball.
The traditional driving range rubber tee is set at one height only and therefore not suitable for use with both woods and irons, i.e. if the tee is set at appropriate height for use with a wood, it is too high to be used with an iron. If on the other hand the tee is set for use with an iron, it is too low to be used with a wood.
When practicing at a traditional driving range mat, including a standard rubber tee, the person using the mat must release the club and move away from the set up position after each and every hit in order to bend down, pick up a new ball and place it on the tee. This severely detracts from the persons ability to repeat each swing as is highly desireable for practice purposes. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates generally to the field of soybean breeding. In particular, the invention relates to the novel soybean variety D4120384.
2. Description of Related Art
There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety an improved combination of desirable traits from the parental germplasm. These important traits may include higher seed yield, resistance to diseases and insects, better stems and roots, tolerance to drought and heat, better agronomic quality, resistance to herbicides, and improvements in compositional traits.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of variety used commercially (e.g., F1 hybrid variety, pureline variety, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, recurrent selection and backcrossing.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable variety. This approach has been used extensively for breeding disease-resistant varieties (Bowers et al., 1992; Nickell and Bernard, 1992). Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful varieties produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s) for generally three or more years. The best lines are candidates for new commercial varieties. Those still deficient in a few traits may be used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, may take as much as eight to 12 years from the time the first cross is made. Therefore, development of new varieties is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to one or more widely grown standard varieties. Single observations are generally inconclusive, while replicated observations provide a better estimate of genetic worth.
The goal of plant breeding is to develop new, unique and superior soybean varieties and hybrids. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The varieties which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same variety twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large amounts of research monies to develop superior new soybean varieties.
The development of new soybean varieties requires the development and selection of soybean varieties, the crossing of these varieties and selection of progeny from the superior hybrid crosses. The hybrid seed is produced by manual crosses between selected male-fertile parents or by using male sterility systems. Hybrids may be identified by using certain single locus traits such as pod color, flower color, pubescence color or herbicide resistance which indicate that the seed is truly a hybrid. Additional data on parental lines as well as the phenotype of the hybrid influence the breeder's decision whether to continue with the specific hybrid cross.
Pedigree breeding and recurrent selection breeding methods are used to develop varieties from breeding populations. Breeding programs combine desirable traits from two or more varieties or various broad-based sources into breeding pools from which varieties are developed by selfing and selection of desired phenotypes. The new varieties are evaluated to determine which have commercial potential.
Pedigree breeding is commonly used for the improvement of self-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F1. An F2 population is produced by selfing one or several F1's. Selection of the best individuals may begin in the F2 population (or later depending upon the breeders objectives); then, beginning in the F3, the best individuals in the best families can be selected. Replicated testing of families can begin in the F3 or F4 generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (i.e., F6 and F7), the best lines or mixtures of phenotypically similar lines are tested for potential release as new varieties.
Mass and recurrent selections can be used to improve populations of either self-or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
Backcross breeding has been used to transfer genetic loci for simply inherited, highly heritable traits into a desirable homozygous variety which is the recurrent parent. The source of the trait to be transferred is called the donor or nonrecurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., variety) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., variety) and the desirable trait transferred from the donor parent.
The single-seed descent procedure in the strict sense refers to planting a segregating population, harvesting a sample of one seed per plant, and using the one-seed sample to plant the next generation. When the population has been advanced from the F2 to the desired level of inbreeding, the plants from which lines are derived will each trace to different F2 individuals. The number of plants in a population declines each generation due to failure of some seeds to germinate or some plants to produce at least one seed. As a result, not all of the F2 plants originally sampled in the population will be represented by a progeny when generation advance is completed.
In a multiple-seed procedure, soybean breeders commonly harvest one or more pods from each plant in a population and thresh them together to form a bulk. Part of the bulk is used to plant the next generation and part is put in reserve. The procedure has been referred to as modified single-seed descent or the pod-bulk technique.
The multiple-seed procedure has been used to save labor at harvest. It is considerably faster to thresh pods with a machine than to remove one seed from each by hand for the single-seed procedure. The multiple-seed procedure also makes it possible to plant the same number of seeds of a population each generation of inbreeding. Enough seeds are harvested to make up for those plants that did not germinate or produce seed.
Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987a,b).
Proper testing should detect any major faults and establish the level of superiority or improvement over current varieties. In addition to showing superior performance, there must be a demand for a new variety that is compatible with industry standards or which creates a new market. The introduction of a new variety will incur additional costs to the seed producer, the grower, processor and consumer; for special advertising and marketing, altered seed and commercial production practices, and new product utilization. The testing preceding release of a new variety should take into consideration research and development costs as well as technical superiority of the final variety. For seed-propagated varieties, it must be feasible to produce seed easily and economically.
Soybean, Glycine max (L), is an important and valuable field crop. Thus, a continuing goal of plant breeders is to develop stable, high yielding soybean varieties that are agronomically sound. The reasons for this goal are to maximize the amount of grain produced on the land used and to supply food for both animals and humans. To accomplish this goal, the soybean breeder must select and develop soybean plants that have the traits that result in superior varieties. | {
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1. Field of the Invention
The present invention relates to an interconnector to electrically connect a plurality of electronic device elements in a serial direction or a parallel direction. Particularly, the present invention relates to a planar type interconnector employed in the connection of solar cells for artificial satellites or diodes, a method of forming such an interconnector, and a join apparatus thereof.
2. Description of the Background Art
The current consumed energy worldwide corresponds to an enormous amount, which is mainly supplied by fossil fuel such as oil or the like. It is expected that the fossil fuel will be exhausted in the near future if the energy consumption increases at the current rate.
In these few years, intensive research of the technology utilizing inexhaustible and clean solar energy has been in progress as the energy source to replace the fossil fuel. Development of solar cells can be referred to as one major technique thereof. In general, the plurality of solar cells constituting the solar battery are arranged adjacent to each other. An interconnector formed of a small piece of metal is provided in order to electrically connect the solar cells in the serial or parallel direction.
An interconnector includes a stress relief portion that absorbs displacement generated between solar cells connected to each other, and at least two connecting portions connected to the solar cells. The invention disclosed in Japanese Patent Laying-Open No. 4-298082 and the invention disclosed in Japanese Utility Model Laying-Open No. 1-125563 can be enumerated as conventional art related to such an interconnector.
FIG. 1A schematically shows a structure of an interconnector disclosed in Japanese Patent Laying-Open No. 4-298082. This interconnector 101 includes a front surface electrode connecting portion 121, a back electrode connecting portion 122, and a stress relief portion 110. As shown in FIG. 1B, front surface electrode connecting portion 121 and back electrode connecting portion 122 have a mesh structure.
The interconnector disclosed in Japanese Utility Model Laying-Open No. 1-125563 includes a first stress absorption portion having a plurality of permeable holes arranged in the row direction with respect to the interconnector, and a second stress absorption portion having a plurality of permeable holes arranged in the column direction.
In order to withstand the displacement generated between adjacent solar cells, an area for connecting or welding sufficient for the connecting portion is required in joining the connecting portion of the interconnector with the electrode portion of the solar cell. In the inventions disclosed in the aforementioned Japanese Patent Laying-Open No. 4-298082 and Japanese Utility Model Laying-Open No. 1-125563, a mesh opening or permeable hole is provided at the connecting portion of the interconnector. Connection with the electrode portion of the solar cell was effected using the opening or permeable hole. In order to ensure a connection area sufficient for the connecting portion of the interconnector, the area of the connecting portion of the interconnector will become larger. In solar cells for artificial satellites, there is a problem that increase in the area of the connecting portion will raise the cost since noble metal such as gold, silver or the like is generally used as the material of the interconnector. Increase in the area of the connecting portion of the interconnector will also reduce the light-receiving area of the solar cell. As a result, there is a problem that the efficiency and output of the solar cell will be degraded.
The provision of a mesh opening or permeable hole at the connecting portion of the interconnector will become the cause of crushing the mesh opening or permeable hole when welding is effected using a weld electrode of a large width. When pressure is applied with the weld electrode in contact with the residual portion of the mesh opening or permeable hole, i.e. the remaining metal portion for welding, stress concentration occurs at that portion to become the cause of damaging the solar cell. For the reliability of the weld portion, welding was effected on one connecting portion between the interconnector and the solar cell using a small weld electrode of a small width. If the area of the connecting portion of the connector is increased, welding must be effected many times on one connecting portion when a small weld electrode is used. A tremendous amount of time will be required for welding to degrade the productivity.
There was also problem that the process of etching is required to form the mesh opening or permeable hole at the connecting portion of the interconnector, resulting in increase of the processing cost. In the case where etching is applied on the connecting portion of the interconnector, automation cannot be facilitated since it is extremely difficult to work on components of a continuous form. Even if a continuous interconnector is formed by working on a continuous form, there was a problem that the cost of the interconnector is increased.
In the case where a continuous interconnector cannot be formed, each produced interconnector must be accommodated in a pallet or the like individually. Extra space to install the pallet is required. There is also the possibility that the produced interconnector may be lost if small in size. | {
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The following description is related to wireless communications. In the background art, SMS-related procedure could not be fully and properly supported in certain types of wireless communication systems. Further, the so-called Machine-to-Machine (M2M) communications or Machine Type Communications (MTC) could not be fully and properly supported in certain types of wireless communication systems. | {
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Conventional multi-phase voltage regulators typically control activation of multiple phases to produce an output voltage to power a respective load. The amount of current consumed by the load can vary over time. For example, a load such as a processor dynamically can change its current draw to optimize performance and efficiency.
For optimal efficiency, the currents supplied by each of multiple phases typically need to be balanced. In other words, it is typically desirable that the current from each of multiple phases is substantially equal. In accordance with conventional techniques, a low bandwidth, low speed algorithm can be used to physically measure current provided by each phase and ensure current balancing via respective adjustments.
However, during load oscillations (such as when there are sudden changes in load current), it is possible that one or two phases conduct more current at the expense of others because it is often very difficult to equalize or balance phases during a transient condition. Current imbalance amongst multiple active phases can lead to undesirable consequences, one of which is inductor saturation (a fall in inductor impedance), which leads to current spikes. The current spikes can cause damage to circuitry. | {
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1. Field of the Invention
The present invention relates to a control system and, more particularly, to a control system which enables a reduction in electric power consumption of backup power by making use of data communications between control units.
2. Description of the Relevant Art
In recent years, a lot of ECUs (Electronic Control Units) have been mounted on vehicles for electronic control, and various types of control have been performed. Among these ECUs, an ECU for EFI for performing fuel injection control of an engine, an ECU for ABS for performing drive control of solenoid valves for hydraulic control and the like, an ECU for a transmission for performing drive control of solenoid valves for shifting and the like, an ECU for air bags for controlling spreading of air bag systems, and an ECU for body work for controlling keyless entry and the like are exemplified. The specifications of these ECUs mounted on vehicles very with car models and grades.
Recently, in order to increase the efficiency of control processing between these ECUs and reduce component costs or the like, multiple ECUs have been mutually communicably connected through a communication line so that they can share data of each ECU.
FIG. 11 is a block diagram schematically showing the construction of a control system including conventional ECUs. Reference numeral 60 in the figure represents a control system, which is constituted of ECUs 50a-50f mutually connected through a communication line 12. A vehicular LAN system is constructed of these ECUs 50a-50f.
The ECU 50a comprises an input circuit 2 to perform input processing of signals from a sensor, a switch and the like, a microcomputer 53 to perform various types of computing based on the input signals captured through the input circuit 2, an output circuit 4 to output control signals computed in the microcomputer 53 to an actuator and the like, a power circuit 5 to provide stable power supply voltage to the microcomputer 53, and a communication circuit 6 for data communications through the communication line 12 with the other ECUs 50b-50f.
The microcomputer 53 comprises a CPU 53a, a ROM 53b and a RAM 53c. In accordance with programs previously stored in the ROM 53b, the CPU 53a performs various types of computations based on the input signals captured from the input circuit 2 or data read from the RAM 53c, and stores the computation results in the RAM 53c or outputs them through the output circuit 4 to the actuator.
A battery 8 is connected through a power line 9a and an ignition switch 7 to the power circuit 5. The 12V power from the battery 8 is converted to 5V power in the power circuit 5, and the 5V power is provided to a power terminal 9c of the microcomputer 53 by turning on the ignition switch 7. In addition, the battery 8 is connected through a backup power line 9b without the ignition switch 7 involved to the power circuit 5. Even while the ignition switch 7 is in the off position, a prescribed constant voltage to which power is converted in the power circuit 5 is supplied to the power terminal 9c of the microcomputer 53. The hardware of any of the other ECUs 50b-50f except the ECU 50a, is almost the same as the above.
In the control system 60 having the above construction, when the ignition switch 7 is turned off, each microcomputer 53 in the ECUs 50a-50f is provided with electric power through the backup power line 9b and the power circuit 5 from the battery 8 even during the off state of the ignition switch 7. As a result, even while the ignition switch 7 is in the off position, data stored in the RAM 53c of each microcomputer 53 is not destroyed, so that the ECUs 50a-50f each can maintain required data.
In recent years, the number of ECUs mounted on each vehicle has been larger and larger. Although the electric current consumption for maintaining data stored in RAM is small on a single ECU basis, with an increasing number of ECUs mounted on each vehicle, the electric current consumption for maintaining data per vehicle becomes considerably large.
According to the above conventional method, with an increasing number of ECUs mounted, the electric current consumption, or dark current for maintaining memory contents increases, so that there is a high possibility of an early dead battery being caused in cases where a vehicle is transported or let stand with the battery connected.
Although efforts to decrease the dark current for maintaining memory contents are being made on a single ECU basis, there is a limit to these efforts as long as the basic construction of an ECU is not greatly changed.
There is a method wherein an EEPROM, being a nonvolatile memory which can maintain data even after power supply cutoff, is mounted and part of the data to be stored in RAM is stored in the EEPROM. However, in general, since the capacity of an EEPROM is small, the amount of data which can be written therein is limited. When the capacity thereof is made large, it becomes expensive, resulting in the limited uses thereof. | {
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A great amount of effort has been devoted to improving methods and materials for delivery of active agents or therapeutics to patients. Oftentimes, the improvements involve increasing the efficiency of drug delivery, improving drug targeting, improving drug delivery profiles, reducing side-effects, or improving drug stability. In some instances, the improvements are achieved by using an excipient, or more particularly a drug delivery vehicle.
Drug delivery vehicles can be employed with implantable devices, some of which are capable of delivering desired doses of a beneficial active agent over extended periods of time. For example, U.S. Pat. Nos. 5,034,229, 5,557,318, 5,110,596, 5,728,396, 5,985,305, 6,113,938, 6,156,331, 6,375,978, and 6,395,292, the contents of each of which are herein incorporated in their entirety by reference, teach osmotically driven devices capable of delivering an active agent formulation, such as a solution or a suspension, at a desired rate over an extended period of time (i.e., a period ranging from more than one week up to one year or more). Other exemplary implantable devices include regulator-type implantable pumps that provide constant flow, adjustable flow, or programmable flow of beneficial agent formulations, which are available from, for example, Codman of Raynham, Mass., Medtronic of Minneapolis, Minn., and Tricumed Medinzintechnik GmbH of Germany. Further examples of implantable devices are described in U.S. Pat. Nos. 6,283,949, 5,976,109, 5,836,935, and 5,511,355, which are herein incorporated in their entirety by reference. This category of implantable devices can be designed to deliver a desired active agent at therapeutic levels over an extended period of time, and, therefore, drug delivery vehicles incorporated with such devices need to account for such extended periods in vivo.
Examples of active agents or drugs contemplated for use with the present invention are biomolecular material that can act as therapeutics. The delivery of such agents over an extended period of time with an implantable drug delivery system has proven difficult for a number of factors. As it is used herein, the term “biomolecular material” refers to peptides, polypeptides, proteins, nucleic acids, viruses, antibodies, and any other naturally derived, synthetically produced, or recombinantly produced active agent that includes nucleic or amino acid. Among other challenges, two problems must be addressed by the device and the delivery vehicle when seeking to deliver biomolecular material over an extended period of time from an implanted delivery device. First, the biomolecular material must be contained within a formulation that substantially maintains the stability of the material at elevated temperatures (i.e., 37° C. and above) over the operational life of the device. Second, the biomolecular material must be formulated in a way that allows delivery of the biomolecular material from an implanted device into a desired environment of operation over an extended period time. This second challenge has proven particularly difficult where the biomolecular material is included in a flowable composition that is delivered from a device over an extended period of time at low flow rates (i.e., ≦100 μl/day).
Biomolecular material may degrade via one or more of several different mechanisms, including deamidation, oxidation, hydrolysis, disulfide interchange, and racemization. Significantly, water is a reactant in many of the relevant degradation pathways. Moreover, water acts as a plasticizer and facilitates the unfolding and irreversible aggregation of biomolecular materials. To work around the stability problems created by aqueous formulations of biomolecular materials, dry powder formulations of biomolecular materials have been created using known particle formation processes, such as by known lyophilization, spray-drying, or dessication techniques. Though dry powder formulations of biomolecular material have been shown to provide suitable stability characteristics, it would be desirable to provide a formulation that is stable over extended periods of time, and, when delivered via an implantable device, is also flowable and readily deliverable from the implantable device.
In the instances when a drug delivery vehicle uses polymeric excipients, such as povidone, crospovidone, and copovidone, these excipients may lead to oxidation of the active agents in the drug formulations due to the presence of peroxides in the polymer preparations. Some examples of active agents that can be sensitive to oxidation, or oxidation-sensitive active agents, include proteins, peptides, ergot alkaloids, and antibiotics such as doxycycline, metformin and molsidomine. Povidone, crospovidone, and copovidone thus have limited utility as solid excipients in formulations containing oxidation-sensitive active agents. To reduce oxidation, freshly prepared polymeric excipients can be used as they typically have lower peroxide levels than polymer excipients that have been stored for a period of time. However, the use of freshly prepared polymer excipients to prepare drug formulations often involves major logistical problems.
Other nonaqueous drug formulations that can be delivered from an implantable device include biomolecular materials that are stable over extended periods of time at elevated temperatures. The nonaqueous vehicle formulations typically include polymers, solvents, and surfactants. Under certain circumstances, when these formulations are exposed to an aqueous liquid, such as a physiological fluid, within a delivery conduit of a device used to deliver the formulations, the polymer included in the vehicle tends to phase separate from the solvent into the aqueous liquid. As the polymer partitions into the aqueous liquid, the concentration of polymer within the aqueous liquid may increase to such an extent that a highly viscous polymer gel or precipitate is formed within the delivery conduit, resulting in a partial or complete occlusion of the delivery conduit and interfering with the desired operation of the delivery device. The potential for such occlusions increases where the geometry of the conduit is such that aqueous liquid interfaces with the drug formulation in a confined area over a relatively long period of time (e.g., hours or days).
A need therefore exists in the art for methods for reducing peroxide levels in delivery vehicles formed from polymer preparations, particularly in drug formulations comprising oxidation-sensitive active agents. There is a further need for such delivery vehicles to be deliverable from an implantable device with reduced potential for occluding a delivery conduit, while providing enhanced stability to the active agent that is intended for delivery. | {
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The present invention relates to intumescent compositions based on foamed or unfoamed polyurethanes which contain a combination of polyester polyols, cyanuric acid derivatives and phosphorus-containing hydroxyl compounds as part of the formulation thereof and which are plastic and elastic in character.
Intumescent compositions are generally understood to be materials which foam under the influence of fire or heat and, in doing so, form an insulating and fire-resistant foam which protects the areas situated behind the foam against fire. Such intumescent compositions are generally known in the form of lacquers, coatings and mortars or cements.
Good intumescent compositions should be able to at least double in volume on contact with a flame and, in addition, should be unaffected by water. It would be of particular commercial interest if these properties could be combined with the absence of halogen, with a low density, with good thermal insulating properties in the absence of stressing, and with plasticity or flexibility and/or elasticity. Elastic-plastic intumescent compositions characterized by high dimensional stability could be widely used in the field of fire prevention in the form of semi-finished products, such as tapes, sheetings, profiles, coatings, granulates or fillings.
The use of melamine in the production of flexible foams using substantially linear polyols, and preferably polyether polyols, is known (see e.g. German Offenlegungsschrift No. 2,815,554). Although foams of this type are flame-resistant and do not burn completely on exposure to a flame, they do not have the character of intumescent compositions. In other words, they do not undergo any increase in volume on exposure to a flame, forming a fire-repellent foam.
According to an earlier proposal, flame-resistant sealing compounds free from phosphorus and halogen may be produced using branched polyesters containing hydroxyl groups. Sealing compounds of this type are not intumescent, i.e., they do not foam on exposure to a flame.
In yet another proposal optionally foamed intumescent compositions are obtained by reacting:
(1) polyisocyanates with PA1 (2) phosphorus-containing condensation products having at least one hydroxyl group obtainable by condensing (i) primary or secondary, aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic monoamines and/or polyamines, which amino or polyamine may contain OH--groups, (ii) carbonyl compounds and (iii) dialkyl phosphites, optionally followed by alkoxylation, and PA1 (3) aromatic hydroxy carboxylic acids or salts thereof and PA1 (4) optionally water and/or other organic compounds containing isocyanate-reactive hydrogen atoms. PA1 (1) polyisocyanates with PA1 (2) phosphorus-containing condensation products having at least one hydroxyl group obtainable by condensing (i) primary or secondary aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic monoamines and/or polyamines, which mono- or polyamines optionally may contain OH--groups; (ii) carbonyl compounds; and (iii) dialkyl phosphites, optionally followed by alkoxylation, and PA1 (3) polyesters containing hydroxyl groups and having an OH--number of from 140 to 300, obtained by reacting polycarboxylic acids containing from 2 to 10 carbon atoms with at least two polyols selected from two different groups of the following three: PA1 (4) cyanuric acid and/or cyanuric acid derivatives and PA1 (5) optionally water and/or other organic compounds containing isocyanate-reactive hydrogen atoms. PA1 R represents C.sub.1 -C.sub.8 alkyl or C.sub.1 -C.sub.8 hydroxyalkyl; and PA1 X represents H or methyl. PA1 n=2-4, preferably 2; and PA1 Q represents an aliphatic hydrocarbon radical containing from 2 to 18, preferably from 6 to 10, carbon atoms, a cycloaliphatic hydrocarbon radical containing from 4 to 15, preferably from 5 to 10, carbon atoms, an aromatic hydrocarbon radical containing from 6 to 15, preferably from 6 to 13, carbon atoms or an araliphatic hydrocarbon radical containing from 8 to 15, preferably from 8 to 13, carbon atoms. Specific isocyanates include ethylene diisocyanate; 1,4-tetramethylene diisocyanate; 1,6-hexamethylene diisocyanate; 1,12-dodecane diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and 1,4-diisocyanate and mixtures of such isomers; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (German Auslegeschrift No. 1,202,785, U.S. Pat. No. 3,401,190); 2,4- and 2,6-hexahydrotolylene diisocyanate and mixtures of such isomers; hexahydro-1,3- and/or 1,4-phenylene diisocyanate; perhydro-2,4'- and/or -4,4'-diphenyl methane diisocyanate; 1,3- and 1,4-phenylene diisocyanate; 2,4- and 2,6-tolylene diisocyanate and mixtures of such isomers; diphenyl methane-2,4'-and/or -4,4'-diisocyanate; naphthylene-1,5-diisocyanate; and the like. PA1 R represents C.sub.1 -C.sub.8 alkyl or C.sub.1 -C.sub.8 hydroxyalkyl, preferably ethyl or hydroxy ethyl; and PA1 X represents H or methyl, preferably H. PA1 (a) hydroxyl compounds containing more than three OH--groups and having a molecular weight of up to 200, PA1 (b) hydroxyl compounds containing three OH--groups and having a molecular weight of up to 150, PA1 (c) hydroxyl compounds containing two OH--groups and having a molecular weight of up to 80, PA1 a:b=(4,5-6,5):(0,1-1,5), PA1 preferably (5-6):(0,2-1) PA1 a:c=(4,5-6,5):(0,5-1,2), PA1 preferably (5-6):1 PA1 to between 5 and 50%, by weight, preferably to between 15 and 25%, by weight, for the phosphorus-containing condensation products containing at least one hydroxyl group (2): PA1 to between 30 and 70%, by weight, preferably to between 60 and 45%, by weight, for the highly branched polyesters (3): PA1 to between 7 and 40%, by weight, preferably to between 15 and 30%, by weight, for the cyanuric acid derivatives (4): PA1 to between 0 and 10%, by weight, preferably to between 0 and 3%, by weight for water (5): PA1 to between 0 and 25%, by weight preferably to between 0 and 15%, by weight, for the other organic compound containing isocyanate-reactive hydrogen atoms.
According to this proposal, polyesters containing hydroxyl groups and melamine may also be used. However, the polyesters in question are not the highly branched, i.e. polyfunctional, polyesters used in accordance with the present invention, but are instead linear polyesters. The products obtained are thus always rigid. | {
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The stator of an electric motor comprises a stator core, consisting of a stack of laminae, having at least two and sometimes more coil windings thereon. The ends of the windings must be connected to insulated lead wires which extend from the stator to the switch or other control circuit for the motor. In addition, it is common practice to provide a motor protector having two terminals, one of which is connected to one of the winding ends and the other of which is connected to a lead wire. The motor protector serves to shut down the motor in the event of an overload or other undesirable operating conditions.
The connections between the insulated lead wires and the ends of the windings are customarily made by crimping connecting devices on the ends of the leads and the winding ends. The terminals of the protector are similarly connected by crimped connectors to the end of one or more windings and a lead wire. It is often necessary to use color-coded lead wires and connect each wire to a specifically predetermined winding end since the lead wires in turn must be connected to predetermined terminals in a switch for controlling the motor.
The manufacturing and assembly procedure described above is relatively costly and time consuming and presents many opportunities for errors or mistakes in wiring the stator. For example, the operations of connecting the lead wires to the winding ends by means of crimped connections is usually carried out by hand with a crimping press and the operator must therefore handle the entire stator each time a crimped connection is made. These crimped connections between the lead wires and the winding ends must, moreover, be insulated since they are adjacent to the stator and the coil windings and the provision of insulation on these connections adds additional labor to the process. Mistakes can arise in wiring the stator since predetermined color-coded wires must be connected to the winding ends and if a mistake is made at this stage, the motor will not be properly connected to the switch for controlling the motor. When a protector is provided, it is customary to connect one or more of the winding ends to the protector and also to connect the protector to a lead wire and these operations add more labor to the process.
The present invention is directed to a combination of a motor stator and a stator connector which greatly facilitates the wiring of the stator and which eliminates many of the manual operations discussed above. The provision of a connector on the stator which can be mated with a complementary connector is also advantageous in that the lead wires can then be produced with a connector on their ends, the complementary connector, as a harness subassembly which can be produced with automatic or semiautomatic machines. Making the connections to the stator would then only require that two connectors be mated with each other. | {
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The present invention relates generally to the field of computing, and more particularly to group by/aggregate query processing in databases.
Columnar databases are being used with increased frequency due to fast query processing response times on modern multi-core computers. Among database operations that are used, group by/aggregate queries are an important, and potentially costly, operation to process. | {
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1. Technical Field
The present invention relates generally to supply management systems and in particular to communications between an enterprise and outside suppliers for that enterprise. Still more particularly, the present invention relates to automatically notifying outside suppliers for an enterprise of design changes relating to the products supplied or services performed by the outside supplier.
2. Description of the Related Art
Improvements and other design changes are frequently required during the life cycle of tools and similar products. Engineers or designers within an enterprise may institute design changes to improve performance, reduce manufacturing costs, or increase compatibility with other products. However, such design changes complicate the supply management process since outside suppliers affected by the changes must be notified.
Currently, notification of outside suppliers regarding design changes is generally a manual and/or physical process. The engineer or designer must identify each outside supplier affected by the change. Modified drawings reflecting the design changes are sent, usually in hard copy form, to the outside suppliers which have been identified. Responses from the outside suppliers, which are also generally in hard copy form, must be correlated to the appropriate change or revision.
In contemporary supply systems, identifying outside suppliers affected by a design change (e.g., part specification and/or drawing changes) is complicated by the global nature of most manufacturing bases. A design change implemented by an engineer in Houston may affect a manufacturer in England or Singapore with whom the engineer has never had contact. Mere transmission of hard copies of the revisions to an outside supplier located on a different continent requires significant time and expense.
It would be desirable, therefore, to automate the process of notifying outside suppliers or other affected parties regarding relevant design changes. | {
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1. Field of the Invention
The present invention relates to techniques for monitoring at least one of a plurality of electric power sources in an electric system wherein a load device consisting at least one electrically operated device is electrically connected to the plurality of electric power sources.
2. Discussion of the Related Art
JP-A-10-336915 discloses an electric system wherein a load device is electrically connected to a plurality of electric power sources. In this electric system, the load device can be operated unless all of the plurality of electric power sources are abnormal or defective. Thus, the provision of a plurality of electric power sources in an electric system increases the operating reliability of the electric system.
However, all of the plurality of electric power sources may be defective or abnormal. If it is possible to detect that at least one but not all of the plurality of power sources is defective, it is possible to inform or warn the user of the load device of that fact, that is, that there is a certain possibility that all of the plurality of power sources will be defective. This information or warning help the user of the load device take an appropriate measure or action for the load device, making it possible to avoid undesirable situations which would result from the abnormality of the power source or sources.
The electric current or voltage applied to the load device to which a plurality of electric power sources at least one of which is monitored as a subject power source are connected does not reflect the present capacity or state of each subject subject power source, that is, the ability of the subject power source to energize or activate the load load. To correctly monitor each subject power source, it is necessary to avoid an influence of the other power source or sources on the state of the subject power source. | {
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I. Field of the Disclosure
The technology of the present application relates to gated diodes and their use in circuits and related methods, including protection circuits, electro-static discharge (ESD) protection circuits, and high speed or switching circuits.
II. Background
Electro-static discharge (ESD) is a major reliability issue in integrated circuits (ICs). ESD is a transient surge in voltage (negative or positive) that may induce a large current in a circuit. To protect circuits against damage from ESD surges, protection schemes attempt to provide a discharge path for both positive and negative ESD surges. Conventional diodes can be employed in ESD protection circuits to clamp the voltage of positive and negative ESD surges to shunt current and prevent excessive voltage from being applied to a protected circuit. FIG. 1 illustrates a conventional ESD protection circuit in this regard. As illustrated in FIG. 1, a voltage rail (Vdd) 10 and a ground rail (GND) 12 are provided to power a protected circuit 14. The protected circuit 14 can be any type of circuit and provided in any form desired. In this example, a terminal in the form of a signal pin 16 provides a signal path to the protected circuit 14 for providing information and/or control to the protected circuit 14. For example, the protected circuit 14 may be included in an IC, with the signal pin 16 being an externally available pin on the IC chip.
A conventional ESD protection circuit 18 may be coupled between the voltage rail 10 and ground rail 12 to protect the protected circuit 14 from ESD surges. The exemplary ESD protection circuit 18 in FIG. 1 includes two conventional diodes: a positive ESD surge diode 20 and a negative ESD surge diode 22. The positive ESD surge diode 20 and the negative ESD surge diode 22 are coupled in series. The positive ESD surge diode 20 clamps positive voltage on the signal pin 16 to one diode drop above the voltage rail 10. The negative ESD surge diode 22 clamps negative voltage on the signal pin 16 to one diode drop below the ground rail 12. A cathode (k) of the positive ESD surge diode 20 is coupled to the voltage rail 10. An anode (a) of the positive ESD diode 20 is coupled to the signal pin 16 at a node 24 on the signal path between the signal pin 16 and the protected circuit 14. A cathode (k) of the negative ESD surge diode 22 is also coupled to the node 24 on the signal path from the signal pin 16 to the protected circuit 14. An anode (a) of the negative ESD surge diode 22 is coupled to the ground rail 12.
For positive ESD surges on the signal pin 16, the positive ESD surge diode 20 will become forward biased and clamp voltage on the signal pin 16 to one diode drop above the voltage rail 10 to protect the protected circuit 14. Energy from such an ESD surge will be conducted through the positive ESD surge diode 20 in a forward biased mode and dispersed into the voltage rail 10. Appropriate ESD protection structures may be implemented (not shown) in the voltage rail 10 to eventually dissipate a positive ESD surge to the ground rail 12. For negative ESD surges on the signal pin 16, the surge is similarly dissipated. A negative ESD surge on the signal pin 16 will place the negative ESD surge diode 22 in a forward biased mode thus providing a low-impedance path relative to the protected circuit 14. Energy from the negative ESD surge will be dissipated into the ground rail 12.
Because circuits are increasingly being provided in system-on-a-chip (SOC) configurations due to higher transistor counts, providing ESD protection in SOC technologies is becoming increasingly important. SOC technologies may employ field effect transistors (FETs) that provide a relatively thin oxide gate dielectric. These relatively thin dielectrics are susceptible to destructive breakdown and damage by excessive voltages from an ESD surge event. Further, conventional diodes, such as the ESD surge diodes 20, 22 provided in FIG. 1, may not provide sufficient conduction for ESD protection in SOC technology.
To address these shortcomings in ESD protection, and for SOC technologies in particular, shallow trench isolation (STI) diodes have been provided in ESD protection circuits. Gated diodes are also being employed in ESD protection circuits. It has been shown that use of a gated diode has superior conductance per unit length as well as turn-on speed due to the transient path of its carriers. Turn-on speed of an ESD protection circuit is important for meeting charge device modeling (CDM) specifications where large amounts of current (e.g., several amps) can flow in a very small fraction of time (e.g., less than a nanosecond) during ESD events. However, even with these advantages of gated diodes, STI diodes are predominantly used in ESD protection circuits for high speed circuits. Gated diodes can unacceptably decrease performance. A gated diode has greater perimeter capacitance per unit diffusion or active length than an STI diode. This is illustrated by example in the modeling graph 26 of FIG. 2, where input capacitance (C) of a gated diode pair 28 and an STI diode pair 30 corresponding to FIG. 1 is plotted versus input voltage (V). This example assumes a 65 nanometer (nm) process. As shown, the input capacitance (C) of the gated diode pair 28, which is normalized to the maximum capacitance of the STI diode pair 30, is higher than the input capacitance (C) of the STI diode pair 30 for given voltage (V), length, and width of the diodes (approximately 8.0 and 0.45 micrometers (μm), respectively). For example, at the rail voltage (Vdd), the normalized capacitance (C) of the gated diode pair 28 is nearly 1.8 whereas the normalized capacitance (C) of the STI diode pair 30 is approximately 1.0. This equates to the gated diode pair 28 having an approximately eighty percent (80%) increase in capacitance over the STI diode pair 30 in this example.
Increased perimeter capacitance in a gated diode increases the load capacitance when the gated diode is added to a protected circuit. Increasing load capacitance can negatively affect protected circuits. For example, increased load capacitance can decrease switching times and frequency performance of a protected circuit, because charging time will be increased due to the ESD protection circuit being coupled to the protected circuit in an R-C circuit arrangement. Further, increased capacitance provided as a result of inserting an ESD protection circuit can decrease the sensitivity of radio frequency (RF) components, such as a low noise amplifier (LNA). However, use of an STI diode having a lower capacitance in an ESD protection circuit also has a trade off over a gated diode. Use of an STI diode in an ESD protection circuit can result in low CDM voltage tolerances for the protected circuit for both positive and negative surges, and especially for protected circuits and related processes employing thin oxide gate oxide dielectric devices coupled to a pad that can be found in large SOC chips.
To preserve performance, chip manufacturers and customers have had to accept the lower CDM voltage tolerances provided by use of STI diodes in ESD protection circuits, which results in greater ESD-related exposure and failures. Thus, a need exists to provide an ESD protection circuit that exhibits superior conductance and turn-on time as well as a low capacitance so as to not adversely affect performance of a protected circuit. | {
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Many electronic systems utilize high voltage signals that exceed the 5V or less logic signal levels of typical digital systems. For example, applications such as communications systems that incorporate modems, serial line drivers, etc., may be required to operate at elevated voltage levels. In many flat panel displays, row and column electrodes are driven by low cost integrated circuits (`ICs`) that must be capable of driving high voltages. Many types of nonvolatile semiconductor memories, e.g. EPROMs, EEPROMs and flash EEPROMs, require on-chip manipulation of high voltage signals in order to control programming. Implantable electronic medical devices, such as pacemakers, often require signal or output voltages in the range of 5V to 40V.
Conventional monolithic high voltage amplifier circuits have been fabricated in special Complimentary Metal-Oxide Semiconductor ("CMOS") processes that permit high voltage operation, since transistors fabricated in conventional low voltage CMOS processes typically break down at voltages around 6V to 10V. Transistor breakdown is due to phenomenon such as zener breakdown of the drain, short channel effects and gate oxide failure. J. Y. Chen, CMOS Devices and Technology for VLSI, Prentice Hall, Englewood Cliffs, N.J., 1990; S. M. Sze, Semiconductor Devices Physics and Technology, John Wiley & Sons, New York, 1985. Double diffused drain structures, thicker oxides and long channel Field Effect Transistors ("FETs") have been used in high voltage processes to achieve higher voltage break down levels. But these modifications result in characteristically larger transistors, i.e. a minimum transistor length greater than about 1.5 .mu.m as compared to less than 0.5 .mu.m for low voltage transistors. Larger transistors limit the integration density of the transistors.
Integrated circuits are generally fabricated with standard (also known in the art as "commodity") CMOS processes that are less expensive than specialty high voltage CMOS processes, but are only capable of reliably supporting voltages at or below 5 volts. Combining large, high voltage transistors with small, low voltage transistors on the same semiconductor substrate can be relatively expensive as a result of additional mask steps in the IC fabrication process. Therefore, specialty fabrication of conventional high voltage circuits raises the cost of manufacturing for applications that require extended voltage ranges.
Integrated circuits that implement high voltage circuitry using a low voltage fabrication process have been reported, but with limited applicability. In these circuits, high voltage n-Field Effect Transistors ("n-FETs") and p-FETs are fabricated by extending the drain terminal of the FETs with lightly doped parasitic implants. See Z. Parpia, C.A.T. Salama and R. A. Hardaway, `Modeling and Characterization of CMOS-Compatible High-Voltage Device Structures,` IEEE Transactions on Electron Devices, Vol. ED-34, No. 11, 1987, pp. 2335-2343; M. J. Declercq, M. Schubert and F. Clement, `5V-to-75V CMOS Output Interface Circuits,` Proceedings of the International Solid State Circuits Conference, San Francisco, 1993, pp. 162-163. These high voltage FETs have lightly doped drain-to-substrate diodes which diodes for standard CMOS fabrication processes typically can sustain voltages of over 40V. These high voltage n-FETs and p-FETs can be used in operational amplifiers and buffer circuits with conventional transistor arrangements.
One of the problems the devices described by Parpia et al. and Declercq et al. have is that the gate oxide between the low voltage gate and the high voltage drain is a thin oxide, which cannot reliably withstand voltages above 5V for most small geometry CMOS processes. Fabricating high voltage devices using small device geometries (i.e. sub micron transistor length) can degrade the transistor significantly and impact long term reliability, if the transistors must sustain voltages above 5V. This degradation is due to the phenomenon of electron tunneling, avalanche breakdown and charge retention in oxide traps. For this reason, previously described high voltage circuits have been restricted to relatively large geometry (i.e. greater than 1.5 .mu.m minimum transistor length) low voltage CMOS processes, a restriction that hinders the integration density and hence applicability of the circuits.
Another problem with the previously described devices is the large gate-to-drain capacitance caused by the overlap of the drain and gate regions. Since the lightly doped parasitic implants are not self-aligned with the gate, as is the case with conventionally fabricated transistors, the overlap and hence capacitance of these transistors can be significantly larger than that of self-aligned transistors. These large capacitances can significantly limit the speed of the transistors.
For applications in which power consumption is a concern, such as battery-powered devices, amplifiers that minimize power-supply currents and have low power-supply voltage operation are desirable. Examples of conventional micropower operational amplifier designs are described in P. E. Allen and D. R. Holberg, CMOS Analog Circuit Design, Holt, Rinehart and Winston, New York, 1987, pp. 497-504. Traditionally, such micropower amplifier designs were unable to provide large output currents while still maintaining micropower consumption when quiescent. A dynamically or adaptively-biased operational amplifier has been described that attempts to overcome this problem by boosting the tail current when a differential input is applied. Degrauwe, et al, `Adaptive Biasing CMOS Amplifiers,` IEEE Journal of Solid-State Circuits, Vol. SC-17, No. 3, June 1982, pp. 522. However, the solution presented by Degrauwe et al suffers from instability problems and requires well-matched components. | {
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A minimum energy optical network is considered to be one that provides point-to-point connection for every pair of end-users. In such a network, each user can transmit to only one other receiver at a time and only the optical transmitter (laser) that is currently transmitting is turned on at any given time. However, given the large number of separate optical channels to choose from, the user node must include a device capable of selecting the proper optical channel and routing the communication payload originating from the user premises equipment (such as a personal computer), to the selected optical transmitter. Similarly, the user node must include a device capable of buffering and delivering to the user, the payload received through each one of its optical channels.
These functions are implemented by certain electronic circuitry. Given that complementary metal-oxide-semiconductor (CMOS) is, and is expected to remain the most energy-efficient electronic technology in the foreseeable future, the best implementation of the transmitting router for the minimum energy optical network should be based on digital CMOS circuits. For the same reason, a receiver at every user node of the minimum energy optical network should also be a digital CMOS circuit.
However, the choice of the implementation technology is not a sufficient guarantee for high energy efficiency of a circuit. In fact, the design of the two devices described above is rather challenging assuming that a large number of optical fibers is originating from one user node. In a conventional implementation, the device on the transmit side would appear as a large 1-to-N digital demultiplexer, where N is the number of optical fibers. As shown in FIG. 2, a 1-to-N demultiplexer 20 would consist of approximately 2N digital 1-to-2 demultiplexers 10, whose logic function is illustrated in FIG. 1 using two two-input NAND gates 12, 14 and one inverter 16. It can be seen from FIG. 2 that each demultiplexer is controlled by one from the set of ‘select’ signals tsel_1 22, tsel_2, tsel . . . k, where k=log 2(N). As a result of this control scheme, each time a new route is selected between the user interface and one of the optical fibers, the ‘select’ signals will change, causing energy dissipation in the 1-to-2 demultiplexers. Assuming that, on the average, one half of the ‘select’ signals change its state and that there are ˜2N demultiplexers, the total dissipation will be proportional to N.
The conventional implementation of the receive routing device is an N-to-1 multiplexer 40 shown in FIG. 4, which consists of about 2N 2-to-1 multiplexers 30, whose logic function is shown in FIG. 3. The logic function is depicted as consisting of 3 NAND gates 32, 34 36 and one inverter 38. Similar to the control in the conventional implementation of the transmit device, the multiplexers in FIG. 4 are controlled by a set of ‘select’ signals rsel_1 42, rsel_2, . . . rsel_k, where k=log2(N) and the resulting dissipation is proportional to N.
The prior art circuits of FIGS. 1 to 4 represent the logic functions for known demultiplexer and multiplexer systems. It will be apparent to a person skilled in the art, that these logic functions can be implemented by many alternative circuits to the ones depicted in these figures.
What is required is a routing device with lower energy dissipation than the conventional routing devices discussed above. | {
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1. Field of the Invention
Certain inventions disclosed herein relate to treating a carotid artery. For example, a carotid artery may have a lesion or a partial occlusion that can be treated using the methods and apparatus disclosed herein.
2. Description of the Related Art
Carotid angioplasty and stenting (CAS) is a minimally invasive approach for treating carotid stenoses. Since its introduction two decades ago, the use of CAS has steadily increased, with 8% of the 107,000 carotid procedures performed in Europe in 2001 utilizing CAS. The prospect of an outpatient procedure without the discomfort of a sizable neck incision appears to be driving patient decision making away from carotid endarterectomy, the standard procedure for carotid bifurcation disease for the past fifty years. | {
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1. Field of the Invention
The present invention relates generally to a system and method for operating a motor vehicle. More particularly, the invention relates to a method for inferring the operational status of a vehicle starter motor.
2. Background Art
Early disengagement of a vehicle starter motor can result in no-start, reverse run and air/fuel mixture conditions that can damage or diminish the longevity of engine components. These problems often arise, for example, when an operator attempts to crank a vehicle""s starter but prematurely releases the vehicle ignition switch. If the switch is not held in the START position for a long enough period of time, a spring mechanism inside the switch will push the key back to the switch""s RUN position, thus disconnecting the battery from the starter solenoid and disengaging the starter motor. Repeated misstarts may degrade the starter motor and reduce its longevity, increase vehicle fuel emissions during vehicle cold start conditions, and also affect a customer""s satisfaction with the vehicle.
As such, in order to prevent reverse run and other conditions that may result in inappropriate ignition of an air/fuel mixture, it is desirable when starting the vehicle to know whether the starter motor is engaged or disengaged. By knowing whether the starter is disengaged, for example, a vehicle""s control system can be operated to cease fuel supply and/or deactivate spark actuation so as to avoid a reverse rotation xe2x80x9cbackfirexe2x80x9d condition of the engine. Knowledge of the starter operational state can also be used in scheduling power-up of other vehicle electrical subsystems or components, for example climate control, entertainment and navigational subsystems. Conventional systems for monitoring starter operation however utilize rotation detectors that typically do not differentiate between forward and reverse rotary motion of the engine. Other alternatives, such as key and rotary position sensors, are costly and more difficult to implement into a typical vehicle control strategy.
Accordingly, the inventors herein have recognized an opportunity for inferring the operational state of a vehicle starter motor by monitoring changes in battery voltage during the vehicle starting process.
The aforedescribed limitations of conventional automobile starting systems are substantially overcome by the present invention, in which a method is provided for determining an operational state of a vehicle starter motor coupled to vehicle battery. The method includes the steps of detecting a vehicle battery voltage, deriving an average (xe2x80x9cfilteredxe2x80x9d or xe2x80x9csteady-statexe2x80x9d) vehicle battery voltage and inferring the operational state of the starter motor based at least in part on a difference between the detected vehicle battery voltage and the filtered vehicle battery voltage.
An advantage of the present invention is that the operational state of a vehicle starter motor can be accurately determined without using an engine rotation detector or starter voltage/current sensor hard-wired to a vehicle""s engine or powertrain controller. In accordance with the present invention, the engagement and disengagement of the starter may be inferred from changes in the battery voltage without wiring and control module costs associated with hard-wired sensors. The disclosed method and system can be used advantageously to minimize occurrences of vehicle no-starts, avoid reverse rotation of the engine and prevent undesired ignition of an air/fuel mixture.
Further advantages, objects and features of the present invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying figures showing illustrative embodiments of the invention. | {
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There are a variety of devices used to treat fractures of the femur, humerus, tibia, and other long bones. For example, fractures of the femoral neck, head, and intertrochanteric region have been successfully treated with a variety of compression screw assemblies, which include generally a compression plate having a barrel member, a lag screw and a compressing screw. Examples include the AMBI″ and CLASSIC™ compression hip screw systems offered by Smith & Nephew, Inc. In such systems, the compression plate is secured to the exterior of the femur, and the barrel member is inserted in a predrilled hole in the direction of the femoral head. The lag screw has a threaded end, or another mechanism for engaging bone, and a smooth portion. The lag screw is inserted through the barrel member so that it extends across the break and into the femoral head. The threaded portion engages the femoral head. The compression screw connects the lag screw to the plate. By adjusting the tension of the compression screw, the compression (reduction) of the fracture can be varied. The smooth portion of the lag screw is free to slide through the barrel member to permit the adjustment of the compression screw. Some assemblies of the prior art use multiple screws to prevent rotation of the lag screw relative to the compression plate and barrel member and also to prevent rotation of the femoral head on the lag screw.
Intramedullary nails in combination with lag screws or other screw assemblies have been successfully used to treat fractures of the femur, humerus, tibia, and other long bones as well. A significant application of such devices has been the treatment of femoral fractures. One such nailing system is the IMHS® system offered by Smith & Nephew, Inc., and covered at least in part by U.S. Pat. No. 5,032,125 and various related international patents. Other seminal patents in the field include U.S. Pat. Nos. 4,827,917, 5,167,663, 5,312,406, and 5,562,666, which are all assigned to Smith & Nephew, Inc. These patents are all hereby incorporated by reference. A typical prior art intramedullary nail may have one or more transverse apertures through its distal end to allow distal bone screws or pins to be screwed or otherwise inserted through the femur at the distal end of the intramedullary nail. This is called “locking” and secures the distal end of the intramedullary nail to the femur. In addition, a typical intramedullary nail may have one or more apertures through its proximal end to allow a lag screw assembly to be screwed or otherwise inserted through the proximal end of the intramedullary nail and into the femur. The lag screw is positioned across the break in the femur and an end portion of the lag screw engages the femoral head. An intramedullary nail can also be used to treat shaft fractures of the femur or other long bones.
As with compression hip screw systems, intramedullary nail systems are sometimes designed to allow compression screws and/or lag screws to slide through the nail and thus permit contact between or among the bone fragments. Contact resulting from sliding compression facilitates faster healing in some circumstances. In some systems, two separate screws (or one screw and a separate pin) are used in order, among other things, to prevent rotation of the femoral head relative to the remainder of the femur, to prevent penetration of a single screw beyond the femoral head, and to prevent a single screw from tearing through the femoral neck and head. When an additional screw or pin is used, however, unequal forces applied to the separated screws or pins can cause the separate screws or pins to be pressed against the sides of the holes through which the separate screws or pins are intended to slide. This may result in binding, which reduces the sliding of the screws or pins through the nail. Conversely, a problem can result from excessive compression of the femoral head toward or into the fracture site. In extreme cases, excessive sliding compression may cause the femoral head to be compressed all the way into the trochanteric region of the femur.
Furthermore, overly rigid nails sometimes generate periprosthetic fractures in regions away from a fracture site. Therefore, it is important that intramedullary nails be adequately flexible in comparison to the bones in which they are implanted. The harder, generally outer portion of a typical bone is referred to as cortical bone. Cortical bone is usually a structurally sound load-bearing material for support of an implant. A cross-section of a long bone that shows the typical anatomical shape of cortical bone generally reveals a non-circular ring of cortical bone which surrounds a medullary canal. Accordingly, the medullary canal generally features a non-circular cross section. Intramedullary nails of the prior art, however, are usually round or square in cross-section, and therefore not anatomically consistent with the cortical bone or the medullary canal. Some have addressed this problem by reaming the medullary canal of the bone with a round reamer in order to cause the nail to fit the cortical bone. This approach, however, can remove significant portions of healthy cortical bone.
The problem of providing an effective load bearing physical relationship between an implant and cortical bone in the proximal femur has been addressed in the art of hip replacement devices. Various hip stems have been developed which feature generally non-circular cross sections along their length, in order better to fit the anatomically shaped cortical bone of the proximal femur and thus more evenly and effectively distribute the load between the stem and the bone. However, none of these hip stems have been incorporated into a nail or configured to accept a screw or screws useful in repairing substantially all of the portions of the treated bone. Instead, hip stems as a general matter have been considered as a device for replacing portions of a long bone, and designed and used for that purpose. For example, the typical application of a hip stem includes completely removing a femoral head and neck, implanting a hip stem, and using the hip stem to support an artificial femoral head.
In summary, and without limitation, the foregoing shows some of the shortcomings of the state of the art in this field. Among other things, what is needed is an orthopaedic implant system that includes a superior sliding screw or other mechanism for applying compression across a fracture. Some embodiments would also provide a sliding screw or other mechanism that obtains adequate bone purchase while reducing the incidence of cut-out, rotational instability, and excessive sliding. An anatomically appropriately shaped implant for achieving improved cortical bone contact would also be advantageous. Where the implant is an intramedullary nail, the nail would provide for reduced reaming and removal of healthy bone. An improved nail may also have a cross-section that provides a greater area of material on the side of the nail that is placed under a greater tensile load when the nail is subjected to a typical bending load. Additionally, an improved implant system could include a sliding screw in combination with intramedullary nails of various designs, or in combination with plates. Combinations of any of these with each other or combinations of each other, and 1 or with other devices or combinations of them also present opportunities for advancement beyond the state of the art according to certain aspects of the present invention. | {
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The present invention is described in the following three papers published by the applicants.
The first paper is N. Praphairaksit et al., xe2x80x9cReduction of Space Charge Effects in Inductively Coupled Plasma Mass Spectrometry Using a Supplemental Electron Source inside the Skimmer: Ion Transmission and Mass Spectral Characteristicsxe2x80x9d, Analytical Chemistry, Vol. 72, No. 11, Jun. 1, 2000, pp. 2356-2361 (the Praphairaksit I paper). An earlier version of this paper is included in U.S. provisional application Serial No. 60/175,688 referred to above as Appendix I.
The second paper is N. Praphairaksit et al., xe2x80x9cAttenuation of Matrix Effects in Inductively Coupled Plasma Mass Spectrometry with a Supplemental Electron Source inside the Skimmerxe2x80x9d, Analytical Chemistry, Vol. 72, No. 11, Jun. 1, 2000, pp. 2351-2355 (the Praphairaksit II paper). An earlier version of this paper is included in U.S. provisional application Serial No. 60/175,688 referred to above as Appendix II.
The third paper is N. Praphairaksit et al., xe2x80x9cReduction of Mass Bias and Matrix Effects in Inductively Coupled Plasma Mass Spectrometry with a Supplemental Electron Source in a Negative Extraction Lensxe2x80x9d, Analytical Chemistry, Vol. 72, No. 18, Sep. 15, 2000, pp. 4435-4440 (the Praphairaksit III paper). An earlier version of this paper is included in U.S. provisional application Serial No. 60/175,688 referred to above as Appendix III.
The Praphairaksit I, Praphairaksit II, and Praphairaksit III papers referred to above are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention is directed to mass spectrometers, and in particular to mass spectrometers wherein space charge effects occur in a sample beam due to an excess of positive ions in the sample beam. The present invention is particularly useful in inductively coupled plasma-mass spectrometers (ICP-MS).
2. Description of the Related Art
FIG. 1 shows a prior-art mass spectrometer which is basically the same as that described in K. Hu et al., xe2x80x9cInductively Coupled Plasma Mass Spectrometry with an Enlarged Sampling Orifice and Offset Ion Lens. I. Ion Trajectories and Detector Performancexe2x80x9d, Journal of the American Society for Mass Spectrometry, Vol. 4, 1993, pp. 16-27 (the Hu I reference), and K. Hu et al., xe2x80x9cInductively Coupled Plasma Mass Spectrometry with an Enlarged Sampling Orifice and Offset Ion Lens. II. Polyatomic Ion Interferences and Matrix Effectsxe2x80x9d, Journal of the American Society for Mass Spectrometry, Vol. 4, 1993, pp. 28-37 (the Hu II reference). One of the authors of the Hu I and Hu II references, Robert S. Houk, is also one of the applicants of the present application. The Houk I and Houk II references are incorporated herein by reference in their entirety.
The prior-art mass spectrometer in FIG. 1 includes an ion source 1, a sampling interface 2, and a mass analyzer 3.
In the Hu I and Hu II references, ion source 1 is an inductively coupled plasma ion source, and mass analyzer 3 is a quadrupole mass analyzer.
Sampling interface 2 includes a sampler 4, a skimmer 5, an ion lens 6, and a differential pumping plate 7. Ion lens 6 includes seven electrodes 8, 9, 10, 11, 12, 13, and 14, which are typically DC electrodes.
In the Hu I and Hu II references, a positive voltage +V1 is applied to a first electrode 8 of ion lens 7, meaning a voltage that is more positive than a potential of skimmer 5.
First electrode 8 may be a cylindrical electrode having holes in it as indicated by the dashed lines in FIG. 1, and may be formed of a mesh.
Ion source 1 generates a quasineutral beam 15 of positive ions and electrons wherein the total positive charge of the positive ions is substantially equal to the total negative charge of the electrons. Sampling interface 2 extracts a portion of quasineutral beam 15 to form a sample beam 16 which is analyzed by mass analyzer 3.
Quasineutral beam 15 and sample beam 16 are shown schematically in FIG. 1 as a single line representing the center lines of these two beams. The shapes of quasineutral beam 15 and sample beam 16 and the trajectories of the positive ions and the electrons in these two beams are described in the Hu I and Hu II references, and elsewhere in the prior art, for example, in H. Niu et al., xe2x80x9cFundamental aspects of ion extraction in inductively coupled plasma mass spectrometryxe2x80x9d, Spectrochimica Acta Part B, Vol. 51, 1996, pp. 779-815 (the Niu reference). One of the authors of the Niu reference, Robert S. Houk, is also one of the applicants of the present application. The Niu reference is incorporated herein by reference in its entirety.
As sample beam 16 passes through sampler 4 and skimmer 5, it is initially a quasineutral beam of positive ions and electrons wherein the total positive charge of the positive ions is substantially equal to the total negative charge of the electrons. However, as sample beam 16 travels downstream from skimmer 5 towards ion lens 6, it changes to a positively charged beam with an excess of positive ions, causing space charge effects to develop in sample beam 16. The reasons for this are described in detail in the Praphairaksit I and Praphairaksit II papers and the Hu I, Hu II, and Niu references.
However, a simplified explanation of the reasons for this is that electrons diffuse away from sample beam 16 as it travels downstream from skimmer 5 towards ion lens 6, creating an excess of positive ions in sample beam 16 and causing sample beam to become positively charged. This causes a space charge field to develop in sample beam 16, thereby causing space charge effects to develop in sample beam 16 as it travels downstream from skimmer 5 towards ion lens 6. Other fundamental reasons for preferential loss of electrons, in place of or in addition to diffusion, are also possible.
The space charge effects which develop in sample beam 16 have numerous disadvantages, and adversely affect the performance of the prior-art mass spectrometer in FIG. 1 as described in detail in the Praphairaksit I, Praphairaksit II, and Praphairaksit III papers and the Niu reference.
FIG. 2 is a diagram showing some consequences of these space charge effects, wherein (xe2x88x92) denotes electrons, (+) denotes light analyte ions, such as Li, and (+) denotes heavy analyte ions, such as U. As shown in FIG. 2, the electrons (xe2x88x92) diffuse away from sample beam 16 as it travels downstream from skimmer 5 towards ion lens 6, creating an excess of positive ions in sample beam 16 and causing sample beam 16 to become positively charged.
For the reasons discussed in detail in the Praphairaksit I, Praphairaksit II, and Praphairaksit III papers and the Niu reference, this causes sample beam 16 to defocus as it travels downstream from skimmer 5 towards ion lens 6, decreasing the number of the light analyte ions (+) and the heavy analyte ions (+) which are available to enter first electrode 8 of ion lens 6. Also, this causes the light analyte ions (+) to defocus to a greater extent than the heavy analyte ions (+), such that the ratio of the abundance (or number density) of the light analyte ions (+) to the abundance of the heavy analyte ions (+) in the portion of sample beam 16 which actually enters first electrode 8 of ion lens 6 is less than the actual ratio of the abundance of the light analyte ions (+) to the abundance of the heavy analyte ions (+) in sample beam 16 where it enters skimmer 5. These effects are particularly troublesome when attempting to measure a small amount of a light element such as Li, in a matrix of a heavy element, such as U, especially when ion source 1 has a high temperature which induces a large variation of ion kinetic energy with ion mass and/or ion mass-to-charge ratio, as described in the Niu reference.
One method of reducing space charge effects in a mass spectrometer is disclosed in S. Tanner et al., xe2x80x9cReduction of Space Charge Effects Using a Three-Aperture Gas Dynamic Vacuum Interface for Inductively Coupled Plasma-Mass Spectrometryxe2x80x9d, Applied Spectroscopy, Vol. 48, No. 11, 1994, pp. 1367-1372. This method uses a three-aperture sampling interface including a sampler, a skimmer downstream from the sampler, and a third aperture downstream from the skimmer which is offset from a beam axis defined by apertures in the sampler and the skimmer.
Another method of reducing space charge effects in a mass spectrometer is disclosed in E. Denoyer et al., xe2x80x9cDetermination of Trace Elements in Uranium: Practical Benefits of a New ICP-MS Lens Systemxe2x80x9d, Atomic Spectroscopy, Vol. 16, No. 1, January/February 1995, pp. 1-6. This method uses a sampling interface including a sampler, a skimmer downstream from the sampler, a grounded shadow stop downstream from the skimmer, and a single cylindrical ion lens downstream from the shadow stop. A voltage applied to the ion lens is dynamically varied in accordance with the mass-to-charge ratio of the ion being analyzed.
The applicants of the present application have invented another method of reducing space charge effects in a mass spectrometer which involves adding electrons to a sample beam having an excess of positive ions to reduce space charge repulsion between the positive ions in the sample beam, thereby reducing space charge effects in the sample beam and producing a sample beam having reduced space charge effects.
The present invention is directed to a mass spectrometer including an ion source which generates a beam including positive ions, a sampling interface which extracts a portion of the beam from the ion source to form a sample beam that travels along a path and has an excess of positive ions over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the excess of positive ions in the sample beam, an electron source which adds electrons to the sample beam to reduce space charge repulsion between the positive ions in the sample beam, thereby reducing the space charge effects in the sample beam and producing a sample beam having reduced space charge effects, and a mass analyzer which analyzes the sample beam having reduced space charge effects. | {
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Field of the Invention
The present invention relates to golfing devices and methods; and more particularly, to golfing devices and methods that are designed to perfect a golfer's swing, increase ball contact and improve golf performance.
Description of the Prior Art
The sport of golfing has become a major entertainment and business industry. Frequently business meetings and dealings take place on the golf course. Social events and outings often are carried out on golf courses. Consequently, individuals of all golfing levels frequently search for methods and devices to improve their golf game. Notwithstanding the plethora of such methods and devices, the improvement of golf prowess can be challenging. Golfers have long known that a proper golf swing is an important component of good golfing technique. Extra care must be taken by the golfer to ensure optimal stroke carry through. A necessary prerequisite for proper golf form is the requirement that a golfer keep his head down during the swing. This condition is actually quite challenging in that golfers frequently forget to keep their head facing downward during the swing and, in doing so, overlook an important swing requirement. Without proper form a tee shot is much less likely to find the fairway.
Golf outings represent a form recreational sporting activity; but additionally provide opportunities to improve business relations, develop inter-company networking and conduct business transactions. For many golfers, the desire to increase performance cannot be understated. While various training devices and methods have been disclosed and utilized, many of these devices and methods are complicated and costly.
Numerous methods and devices have been proposed that attempt to improve a golfer's performance. Such devices and methods are summarized herein below.
U.S. Pat. No. 3,435,554 to Philips discloses a sparking hammer generally having a lower head portion provided with an external bellows, to which is secured a plate. A striker bar, serrated on its exterior, frictionally engages flint secured to the oscillating extension of a spring in order that it will engage the serrations of the striker bar, when the bellows of the lower head portion strikes a surface.
U.S. Pat. No. 3,947,027 to Brown discloses a high performance golf tee having a stem, a cup-shaped ball receptacle on the top of the stem, and a projection extending outwardly from the ball receptacle. The extension distance is such that when a golf ball is placed on the tee and a golf club is swung at the ball, the golf club contacts the projection and imparts motion to the ball before the golf club makes direct contact with the surface of the golf ball. The contact between the golf club and the projection imparts an initial backspin on the ball.
U.S. Pat. No. 3,992,011 to Jessee discloses a heads down golf practice device having a resilient tubular golf tee member mounted in and protruding upwardly from a resilient, flat tee support structure base. The base includes a light emitting assembly having a light visible through the interior portion of the resilient tubular golf tee and mechanical indexing elements for randomly selecting a color of the visible light. It does not teach or discloses a golf tee having a contact alert coating.
U.S. Pat. No. 4,131,280 to Poortman discloses an electronic tee off device having a plurality of light-emitting diodes of different colors. These diodes are situated at a location where, when energized, they are visible to a golfer when the golfer is properly positioned with respect to a golf ball appointed to be driven from a tee.
U.S. Pat. No. 4,898,389 to Plutt discloses a self-contained gold training device designed to be integral with, or attached to and detached from the head of any golf club. The device gives a golfer an exact indication of the point of impact of the face of a golf club with a golf ball.
U.S. Pat. No. 5,085,431 to McGuire discloses a golf tee providing a pliant riser and a rigid anchor. A placement tool providing means for placement of said golf tee into the ground. The anchor having enough length and exposed surface area to provide the required friction needed to hold said golf tee firmly in place even after being struck by a golf club used to hit a golf ball teed up on said golf tee. The placement tool consisting of a tool handle, a tool shaft and a tool sleeve is used to place said golf tee into the ground such that the anchor head is below the ground surface a distance calibrated by the tee height indicator on the riser. There is no disclosure of a coating on the placement tool, which is utilized for placing a golf tee into the ground. Furthermore, the placement tool and golf tee do not emit a spark that immediately indicates proper golf stroke form.
U.S. Pat. No. 5,120,358 to Pippett discloses that determination of the point of impact on a golf club face with a golf ball is facilitated through the use of a flowable chalk compound placed on the ball at the intended point of contact with the club face. The flowable chalk compound includes a homogeneous, paste-like mixture of a major proportion of a solid, finely divided pigment and a minor proportion of a grease-like material. Upon impact, the chalk compound will make a visible mark on the club head face that may be observed by the golfer. There is no disclosure of a coating on the golf tee. Instead the chalk compound in placed on the ball. Furthermore, the chalk compound does not provide immediate feedback concerning of the golf club stroke, since the club head face must be observed after the golf swing in order to discern the point of contact between the club head and the ball.
U.S. Pat. No. 5,356,146 to Blosser discloses a golf tee having successive contrasting color stripes around most of its length. A golfer can determine at a glance how many of the stripes are exposed above the ground in which the tee is set, and thereby determine the height of a golf ball on the tee above the ground. The stripes are arranged in repeated sequences with two or more different colors in each sequence.
U.S. Pat. No. 5,597,361 to Hope discloses a self-adhesive indicator which adheres to a golf club face to provide an indication of the point of impact of the golf ball on the club face. The indicator consists of a sandwich of various layers--a layer of pressure-sensitive adhesive on the bottom, followed by a layer of energy-absorbing elastomeric material on which is provided a film of a thermochromic material such as a temperature sensitive liquid crystal, followed by a top layer of clear high impact plastic.
U.S. Pat. No. 5,830,077 to Yavitz discloses a device for assisting a golfer in improving his or her golf swing. The device includes an impact detector mounted to the club head of a golf club. The impact detector provides an instantaneous visual or audible indication of when a predetermined area, e.g., the “sweet spot”, of the club head face strikes the golf ball. There is no disclosure of a coating on the golf tee. Instead the impact detector is mounted to the club head. Modifying the golf club head by mounting the impact detector thereon would disqualify the golf club and lead to stroke penalties if the club were used in recreational and tournament play. Standard regulated golf clubs and golf balls must be unadulterated or un-manipulated as required under golf organization rules and regulations of the United States Golf Association (USGA).
U.S. Pat. No. 5,890,976 to Anderson discloses an encasement device for a golf tee cylindrically adhered to a shaft of golf tee. The encasement device is a cover with graduated markings, which allow the golfer to consistently set the tee at the golfer's desired depth. Each graduated marking is numerically related to other graduated markings and the ground penetration depth. The resulting multi-layer structure of the golf tee and the encasement device deters breakage of the golf tee and reinforces the shaft structure of the golf tee.
U.S. Pat. No. 6,319,156 to Alexsen discloses a biodegradable golf tee having fertilizer properties, as well as a method of making the golf tee.
U.S. Pat. No. 6,832,964, U.S. Patent Application Publication Nos. 20040162153 and 20050101413 to Adams et al. disclose a golf tee coated with colored coatings which, when struck with a golf club, leave a marking that easily identifies where the ball was struck on the club face and the path of the swing, but does not come off in normal handling. The tee leaves a multi-colored marking on the club face that is used to show the swing path of a golfer's swing and the point of impact of the tee on the face of the golf club. There is no disclosure of a spark coating on the golf tee. Instead a colored coating compound leaves a mark on the golf club face. Furthermore, the colored coating does not provide immediate feedback regarding the golf club stroke, since the club head face must be observed after the golf club swing in order to discern the point of contact.
U.S. Pat. No. 7,169,067 to Town discloses a swing training device. A microprocessor controlled set of colored LEDs teach the user to watch the ball during contact by a ball hitting device such as a baseball bat or golf club.
U.S. Pat. No. 7,604,554 to Otsubo discloses a golf tee implementing an anchoring device, an impact energy deflection device and a friction reduction device in one-piece configuration. The tee anchoring device comprises two anchoring fins for initial impact resistance and the recoil dislodgement prevention fin after-impact resistance.
U.S. Pat. No. 7,959,525 to Brown discloses a dual composition polymeric device to be used as a golf tee. The device has a polymeric hollow stiff stem portion with an integral cone portion at its top end; a cone-shaped polymeric flexible face portion mechanically joined to the cone and stiff stem portion; an internal air passage through the center of the cone-shaped flexible face; and a removable mechanical screw joining the cone-shaped flexible face portion with the stiff stem portion and its integral cone portion.
U.S. Pat. No. 8,083,615 to Wood et al. discloses a set of golf tees. The set includes at least a low spin golf tee and a high spin golf tee. The low spin golf tee is constructed to provide decreased resistance to the deformation of a golf ball that is impacted by a golf club while resting on the low spin golf tee.
U.S. Patent Application Publication No. 20050127630 to Kuhlman et al. discloses a spark-emitting device for a skateboard. The spark-emitting device includes a housing and a plurality of misch metal barrels inserted into a housing and spaced apart so that the wear rate of the housing in the misch metal barrels is compatible and a desired sparking effect is achieved. The spark-emitting device for a skateboard is not utilized for golf purposes; no disclosure is contained therein regarding a spark-emitting tee for golf play.
U.S. Patent Application Publication No. 20090143159 to Murph et al. discloses a golf club that provides a universal training tool for golfers of all sizes. The golf club includes an adjustable length shaft having a club head secured at one end thereof and a handle secured at the other end thereof. A sensor circuit disposed in the club head includes a first sensor adapted to generate and transmit a first measurement signal representing a first desired characteristic of the golf club, and a display circuit disposed in the handle.
U.S. Patent Application Publication No. 20130165273 to Delisle et al. discloses a golf tee including an elongate shaft having opposed upper and lower ends, the lower end configured to be inserted into an underlying surface; and a support cup that is configured to support a golf ball from beneath and that merges with the shaft. The support cup has a base portion and further includes at least three arcuate support prongs projecting upwardly from the base portion. The support prongs define a discontinuous annulus about the periphery of the support cup. There is no disclosure of a spark induction coating on the golf tee. Inasmuch as no spark is generated, the golf tee does not provide immediate feedback regarding the golf club stroke.
Foreign Patent Publication No. WO/2011/078469 to Ru discloses a golf tee that prevents the golfer from raising his head up. The golf tee construction comprising inter alia a light emitting lamp built in a laid portion.
None of the heretofore disclosed and/or utilized devices or methods provides a training aid that is economical to produce, easy to use and reliably assists a golfer to achieving proper golfing form. Specifically, none of the heretofore disclosed and/or utilized devices or methods provides a golf tee that is inexpensive to construct, reliable in operation, and provides a readily accessible and entertaining way to improve one's golf swing and provide immediate evidence of the optimal stance and follow through required for proper swing form.
There exists a need in the art for a device or method that provides a low cost, reliable training aid that is easy to use and assists a golfer to achieving proper golfing form. In addition, there exists a need in the art for a golf tee that is inexpensive to construct, accurate and reliable in operation, and provides a readily accessible and entertaining way to improve one's golf swing and provide immediate evidence of the optimal stance and follow through required for proper swing form. Further, there is a need in the art to provide a golf tee achieving these features that can be used in compliance with rules and regulations of golf courses and tournaments, for use with standard regulation golf clubs and golf balls. | {
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1. Field of the Invention
The present invention relates to a radiator attachment structure for a saddle-ride type vehicle.
2. Description of Background Art
A motorcycle is known that includes a vehicle body frame having a pair of down tubes extending from a head pipe respectively on the left and right sides; and a radiator disposed between the pair of left and right down tubes. See, for example Japanese Patent No. 2834998.
In this motorcycle, the radiator is formed with a thickness substantially equal to the outer diameter of each of the down tubes, and side plates are fixedly disposed respectively at the left and right sides of an upper portion of this radiator. The radiator is then supported between both down tubes with the side plates therebetween. A support pin is attached and fixed to the lower end of the radiator. The support pin is supported by a cross pipe with a shock absorbing rubber member therebetween with the cross pipe being between the both down tubes. With this support structure, the radiator is disposed in a positional relationship in which the front surface of the radiator is substantially flush with the front edges of the down tubes. Further, a net screen is attached to the front surface side of the radiator, and this screen protects the radiator.
However, in the conventional structure, the pair of left and right down tubes and the screen are respectively formed in linear shapes in a side view, and the screen is disposed in a way to overlap with the linear shaped down tubes while being flush with the front surfaces thereof. Thus, the shapes of the down tubes are limited. In addition, when the radiator is disposed to be inclined forward and the forward inclination angle of the radiator thus is large, that is, when the radiator is laid, it is difficult to efficiently intake a flow of air. Thus, in order to improve the cooling performance, measures to make the radiator larger or the like need to be taken.
Even if the down tubes are curved in the side view without considering the aforementioned limitation, the radiator or the like existing between the curved portions is exposed and is highly visible in the side view because the upper end and lower end of the radiator are fixed to the down tubes.
On the other hand, in a case where the radiator is formed in a curved shape along the curved portions of the down tubes in order to avoid exposure of the radiator from the curved portions of the down tubes, the radiator needs to be designed exclusively, and it is difficult to use a versatile radiator. For this reason, a general radiator, which is formed in a linear shape in the side view, that is, one whose entire shape is in a rectangular solid is preferred. | {
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The present invention relates to a semiconductor protection device for protecting a semiconductor switch which generates a surge voltage at the time of current interruption and a power converting system using the same.
As a power electronics system such as a motor driving power converting system, an inverter is known. As a switching element used in the inverter, recently, an IGBT (Insulated Gate Bipolar Transistor) is widely used. In this type of inverter, a protection circuit is used for protecting the IGBT from a surge voltage generated at the time of turn-OFF of the IGBT which is turned ON/OFF at the frequency of 50 Hz to 20 kHz.
As the above type of protection circuit, a clamp type snubber circuit (charging type RCD snubber circuit) shown in FIG. 35 is conventionally used. The clamp type snubber circuit is provided for a series circuit including a filter capacitor Cf for supplying a circuit voltage, a wiring inductance Lm and two IGBTs 1 and 2 which are used as switching elements. More specifically, series circuits including snubber capacitors C1 and C2 and snubber diodes D1 and D2 are respectively connected in parallel with the IGBTs 1 and 2. One-side ends of snubber resistors R1 and R2 are respectively connected to nodes between the capacitors C1 and C2 and the diodes D1 and D2. The other ends of the resistors R1 and R2 are respectively connected to the emitter of the IGBT 2 and the collector of the IGBT 1.
That is, the clamp type snubber circuit has a construction in which the capacitors C1 and C2 are cross-coupled and previously charged to a circuit voltage. At the turn-OFF time, energy stored in the wiring inductance Lm is discharged, and when an instantaneous excessively high voltage (which is hereinafter referred to as a surge voltage) higher than the circuit voltage is applied to the IGBTs 1 and 2, charges are stored (excessively charged) in the capacitors C1 and C2 to clamp the surge voltage. This operation occurs at each turn-OFF time. Since the energy loss corresponds to an excessively charged amount of charges, the clamp type snubber circuit has an advantage that the energy loss is small in comparison with a completely discharging type snubber circuit.
However, the surge voltage suppressing function of a snubber circuit using a capacitor, i.e., either of the completely discharging type snubber circuit and the clamp type snubber circuit, has a disadvantage that the magnitude of the generated surge voltage varies, depending on the magnitude of an interruption current. For example, a surge voltage of 400V is generated when the interruption current is 100 A as shown in FIG. 36 and a surge voltage of 800V is generated when the interruption current is 200 A as shown in FIG. 37. Thus, the surge voltage varies according to the magnitude of the interruption current.
In this case, 100 A corresponds to 100% of a normally used current area of the switching element and 200 A is an excessive current set value such as an accident current and corresponds to 200% of the normal current. In the above application method, a circuit a voltage (1000V)+surge voltage (800V)+marginal amount (200V)=2000V is used as the breakdown voltage of the element. That is, the breakdown voltage of the element becomes approximately 200% of the circuit voltage.
The above relation can be expressed by use of a reverse bias safe operating area (RBSOA) which is necessary for the characteristic of the element, as shown in FIG. 38. That is, it is necessary to safely interrupt the maximum excessive current at the circuit voltage (1000V) and safely interrupt the steady-state current at the maximum voltage (1800V). As is clearly seen from FIG. 38, the safe operation is required in an area higher than the circuit voltage (1000V). However, in the high breakdown voltage area, holes and electrons are easily generated by the avalanche breakdown so as to abruptly make it difficult to attain the safe operation. Therefore, particularly, in order to develop IGBTs which can be used in an area higher than the circuit voltage 1000V, some restrictions for reducing the current used are required, for example.
Further, the clamp type snubber circuit has a cross-coupled wiring and cannot be applied to a circuit in which one arm includes serially connected two or more IGBTS. Therefore, in a high voltage converting system having a plurality of IGBTs serially connected, there is a problem in that a usable snubber circuit of small loss is not realized, but, as a result, a non-charging type snubber of large loss is used.
On the other hand, there is a circuit system having a combination of a snubber circuit and a protection circuit against the excessive voltage, as shown in FIG. 39. The operation of the above circuit is explained with reference to FIGS. 40 and 41.
First, if IGBTs 1 and 2 interrupt a normal current i1 (=100 A at maximum), a surge voltage is generated and it is suppressed to V1 (=1400V at maximum) by a clamp snubber. V1 is suppressed to 150% (=1500V) of the circuit voltage at maximum if the normal current i1 is interrupted. However, if an excessively large current ioc (=200 A at maximum) generated at the time of accident of load short circuit is interrupted, a high surge voltage (1800V) is generated in the clamp snubber circuit. Therefore, it reaches an excessive voltage protection level Vzd (for example, 170% of the circuit voltage=1700V) and is clamped at Vzd, as shown in FIG. 41.
Thus, the element breakdown voltage in a case where the temporary excessive voltage protection circuit of FIG. 39 is attached becomes 1700V+marginal amount 200V=1900V. In this case, an element whose breakdown voltage is lower than the element breakdown voltage 2000V, attained when only the clamp snubber circuit of FIG. 35 is used, can be used, but the difference in the breakdown voltage is small. Since electric energy indicated by the oblique line in the voltage suppressing period is discharged at the turn-ON condition, a current of an amount larger than that of the current flowing at the normal turn-OFF time flows as shown in FIG. 41. Like the case of FIG. 38, the RBSOA of this case is required so that the steady-state current can be safely interrupted at the time of maximum voltage 1700V, and therefore, significant improvement cannot be expected.
Further, an excessive voltage protection circuit different from the excessive voltage protection circuit shown in FIG. 39 is disclosed in Japanese Patent No. 2622524 and Jpn. Pat. Appln. KOKAI Publication No. 7-288456. In the construction disclosed in the above publications, an auxiliary switching element such as an FET or IGBT is connected in parallel with a main switching element and an excessive voltage sensor is provided for the auxiliary switching element. If an excessive voltage is applied, the auxiliary switching element is operated to protect the main switching element from the excessive voltage.
However, the protection method in the above cases is the same as that used in the conventional construction shown in FIGS. 40 and 41 and no improvement can be expected from the viewpoint of utilization factor of the element breakdown voltage. That is, an excessive voltage protection level which is sufficiently higher (for example, 170% as explained in the former case) than the circuit voltage is set and a design is made such that the surge voltage does not exceed the level. Further, the significant improvement cannot be expected from the viewpoint of the RBSOA.
Further, in a case where IGBTs 1 and 2 are connected in parallel instead of using the single IGBT, the characteristics of the IGBTs 1 and 2 are different from each other and the currents flowing therethrough are unbalanced. At this time, a high surge voltage is applied to the snubber circuit by one of the IGBTs which interrupts a larger current. Further, if the IGBTs 1 and 2 are connected in series, surge voltages generated in the IGBTs 1 and 2 at the turn-OFF time become unbalanced and an excessively high surge voltage is applied to one of the IGBTs.
As describe d above, in the conventional snubber circuit, since the surge voltage becomes high in proportion to the magnitude of the in terruption current, the utilization factor of the voltage of the main IGBT is lowered according to the margin for destruction by the excessive voltage. That is, no problem occurs when the interruption current is small as shown in FIG. 36, but when the interruption current is large as shown in FIG. 37, the breakdown voltage is 2000V with respect to the circuit voltage 1000V and the utilization factor is lowered to approx. 50%. Likewise, in a case shown in FIG. 41, the element breakdown voltage is 1900V while the circuit voltage is 1000V and the utilization factor becomes 52.6% and can be enhanced only by 2.6%.
From the viewpoint of the RBSOA, it is required to safely turn OFF the element at a high voltage of 800V or 700V with respect to the circuit voltage 1000V. Further, in the snubber circuit, since the external dimensions of the capacitor and resistor are large, the external dimension of the capacitor becomes extremely large and it becomes difficult to cool the resistor when the breakdown voltage becomes high.
Further, there is a problem that a clamp type snubber circuit of small loss for series connection is not present. Also, there occurs a possibility that surge voltages generated at the time of interruption of the current flowing in the series-connected IGBTs will not be uniformly generated in the respective IGBTs and an excessive voltage is applied to one of the IGBTs to destroy the IGBT.
If the main IGBTs are connected in series or in parallel, the voltages or currents thereof occurring at the switching time become unbalance depending on the characteristics of the main IGBTs. In order to eliminate the unbalanced state, it is required to set the characteristics of the main IGBTs equal. This lowers the yield of the IGBTs and raises the cost thereof.
Further, if the voltages become unbalance at the time of switching of the main IGBT, it becomes difficult to standardize the main IGBT and the peripheral circuit thereof. In this case, it becomes necessary to select the main IGBT and snubber circuit each time the power converting system is formed and the cost thereof may be raised. | {
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Porous substrates are available for various filtration and separation processes. For example, porous substrates with catalytic materials deposited on the substrate are commonly used to reduce particulate emissions and convert toxic exhaust gas into less toxic gases. In certain applications, the chemical conversion is also a useful step in synthesis of intermediate or final compounds. Substrates that have relatively high porosity (i.e., percentage of void space in the material) and relatively high thermal shock resistance (e.g., due to low thermal expansion) may provide the greatest efficiency and effectiveness.
Porosity is generally defined as the percentage of void space in a material. For example, in a substrate with 50% porosity, half of the volume of the substrate is void or open space within the substrate material. Higher porosity in a substrate corresponds to a lower mass per volume in the substrate, which is beneficial when the application requires an elevated operational temperature. For example, when a substrate is used in a catalytic process requiring a high operational temperature, a substrate with a low thermal mass will heat to the operational temperature faster than a substrate with a higher thermal mass, resulting in a shorter light off time for the catalyst.
While porosity is important for filtration and emissions control substrates, even a highly porous substrate is ineffective as a filter where gases have to flow through the filtration medium if it isn't also highly permeable. Permeability is generally defined as the measure of the ability of a material to transmit fluids. For example, in an emissions application, a highly porous substrate cannot effectively filter and convert the exhaust from a vehicle if the exhaust gas cannot flow through the substrate. Thus, it is important for the pores to be interconnected in order to obtain optimal flow through.
Substrates used as a support for catalytic reactions are typically coated with a washcoat, or a high surface area carrier coating, which may be subsequently catalyzed through the addition or impregnation of precious metals or catalytic materials. The washcoat provides high surface area for the dispersion of and stabilization of catalytic materials. In honeycomb substrates, such as the type typically used in exhaust emission controls, the washcoat is deposited over the entire wall of the honeycomb channels. In this flow-through configuration, the limitations on the amount of washcoat coating are dictated by the backpressure resulting from channel size reduction. In a porous substrate, particularly when configured in a wall-flow configuration as a filter, the washcoat limitations are dictated by the backpressure resulting from a reduction in porosity and permeability as the washcoat materials fill the void space within the porous substrate.
The washcoat materials are typically applied through the use of an aqueous slurry of a colloidal suspension of the washcoat materials, such as alumina powder and/or other refractory oxides, or from solution based methods. In the case of a slurry process, the washcoat materials are dispersed in an acidified water-based solution, and mixed using a high shear mixing process. The particle size of the washcoat materials must be carefully controlled to ensure proper adhesion and penetration when applied to the substrate material, and the viscosity of the slurry must be carefully controlled. The slurry is applied to the substrate, typically by pouring the solution into the substrate, which is then dried and calcined. In the case of a solution process, washcoat components, usually in the form of soluble salts in an aqueous solution that are applied to the substrate, dried and then calcined.
Extrusion of ceramic powder materials, and subsequent washcoat loading has proven to be an effective and cost efficient method of producing ceramic substrates for the environmental controls industry. However, there is an upper limit to the porosity in extruded ceramic powder materials that, if exceeded, results in low strength and decreased functionality. Further, porosity of a fired substrate may be reduced in post-production catalyst deposition, in which a washcoat, or surface enhancer, and/or precious metal catalyst material is applied to the finished substrate, potentially filling in voids, or pores, in the substrate.
In addition, the deposition of the washcoat to a fired ceramic honeycomb substrate adds an extra step in the processing and increases the cost of the washcoated substrate. Often, when a high washcoat loading is required, multiple washcoat processing steps have to be taken, which increase the cost and reduce uniformity of the washcoat loading.
Thus, there exists a need for a high-porosity filter substrate in which the washcoat and/or catalyst is included during production. | {
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In typical prior isolating pressure sensors the pressure responsive element, e.g. pressure gauge, senses the pressure of the process fluid flowing in the line through an intermediary sensing fluid isolated from the process fluid by a resilient pressure transmitting member. Such isolating pressure sensors may be used, for example, where contact with the process fluid (e.g. an acid) would damage the pressure gauge. U.S. Pat. No. 3,163,529 and No. 3,563,095 disclose examples.
In one type of prior isolating pressure sensor for interposition coaxially between flanged ends of a coaxially opposed pair of pipeline sections, a U-shaped tube of resilient material contains the sensing fluid. A rigid body member interposed between the pipeline flanges has a bore coaxial with the pipeline. A circumferential, radially inward facing groove in the bore houses the hemicircular bight of the U-shaped tube. The ends of the tube extend tangentially from the bore through elongate parallel passages in an eccentrically extended portion of the body member and connect at the radially outboard end of the latter through fittings to a closable fill plug and a pressure gauge.
Several apparent problems are noted in prior systems of the latter type. Several factors tend to limit sensitivity, including exposure of the sensing fluid containing tube to less than the full circumference of the pipeline passage, location of a major portion of the sensing fluid tube out of contact with pipeline pressure, and (to limit the tendency of the bight portion of the tube to be swept from its groove by fluid flow through the pipeline) the desirability of relatively stiff tube material and of housing most of the cross section of the tube snugly within the groove and which tends to limit free expansion and contraction of the tube in response to changes in pipeline pressure. Also, such prior systems are complicated by the need for special connectors to connect the ends of the resilient tubing within the body member to rigid pipe fittings for the pressure gauge and fill plug. Further, substantial variations in pipeline pressure may tend to push and pull the tangential portions of the tube and cause same to creep axially, creating difficulty in maintaining a seal at the tube ends and in maintaining the tube bight portion in its groove at high process fluid flow rates. Further, although a circular cross section is compatible with conventional end connectors, such circular cross section is inherently more resistant to flexure of the tubing wall than would be a flat cross section, again tending to reduce sensitivity to small changes in pressure in the pipeline fluid.
A second type of prior isolating pressure sensor avoids some of the difficulties noted above, and provides an axially elongate body member of substantially U-shaped wall cross section having a cylindrical central portion terminating in radially outwardly extending end flanges. A resilient cylindrical member is coaxially spaced within the body member by an elongate annular sensing fluid chamber. Annular end plates coaxially fixed to the body member flanges axially press radially outwardly extending end flanges on the resilient member into corresponding, annular axially outward and radially inward opening reliefs at respective ends of the central portion of the body member for the purpose of sealing the ends of the annular fluid chamber. A pressure sensor of this latter kind is disclosed in aforementioned U.S. Pat. No. 3,563,095, assigned to the assignee of the present invention, and has been found to be generally satisfactory in use.
However, in a continuing effort to improve isolating pressure sensors, the present applicant has found that further improvement is possible, for example by reducing cost of and space required for the pressure sensor, particularly for larger diameter pipe systems, and in terms of positive securement of the resilient cylinder member.
Accordingly, the objects of this invention include provision of:
An isolating fluid pressure sensor for a pipeline in which a resilient cylinder, separating a surrounding sensing fluid space from process fluid flowing in the pipeline, has ends positively locked against inadvertent removal from the pressure sensor, even under difficult conditions, e.g. relatively high process fluid flow rates, changing and high process fluid pressures, use with thick or high friction process liquids, etc.
A pressure sensor, as aforesaid, which is compact in axial and radial thickness, and which can be securely sandwiched between end flanges of coaxially opposed pipe sections entirely within the confines of a standard flange bolt circle.
A pressure sensor, as aforesaid, in which the same pressure sensor unit may be used between various styles of pipe flanges without modification, despite substantial variation in bolt hole size, number and location, given correspondence in the internal diameter of the pipe flanges and the pressure sensor.
A pressure sensor, as aforesaid, which is of simple, economical construction.
A pressure sensor, as aforesaid, in which the pressure sensor can be stored and shipped precharged with sensing fluid without fear of leakage past the resilient cylinder, but wherein bolting of the pressure sensing unit between coaxial pipeline flanges tends to even more tightly seal sensing fluid and process fluid interfaces in the sensor.
Other objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings. | {
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The present invention relates generally to the packaging of electronic components. More particularly, the present invention relates to methods for making bond wire pressure sensor die packages.
FIG. 1A illustrates a pressure sensor die 10 suitable for use with the present invention. In one embodiment, pressure sensor die 10 is a piezoresistive pressure sensor. Piezoresistive pressure sensors are discussed, and one method for making piezoresistive pressure sensors is disclosed, in U.S. Pat. No. 5,719,069, entitled xe2x80x9cONE-CHIP INTEGRATED SENSOR PROCESSxe2x80x9d, issued Feb. 17, 1998 to Sparks, which is incorporated, in its entirety, by reference herein. Another type of pressure sensor is disclosed in U.S. Pat. No. 3,748,571, entitled xe2x80x9cPRESSURE SENSITIVE TRANSDUCERS EMPLOYING CAPACITIVE AND RESISTIVE VARIATIONSxe2x80x9d, issued Jul. 24, 1973 to Kurtz, which is also incorporated, in its entirety, by reference herein.
Pressure sensors and pressure sensor die assemblies are well known to those of skill in the art and come in a large variety of sizes and configurations. Consequently, while one embodiment of a pressure sensor die 10 is discussed below, it will be recognized by those of skill in the art that numerous other types of pressure sensors will work equally well with the present invention.
Referring back to FIG. 1A, pressure sensor die 10 includes a pressure sensitive micro-machine element 54 which is a pressure sensing membrane composed of a portion of the epitaxial silicon layer 16. Pressure sensor die 10 also includes a plurality of piezoresistors 14 formed in epitaxial silicon layer 16. Piezoresistors 14 serve as sensing elements for micro-machine element 54.
Pressure sensor die 10 is formed by bonding a Substrate 18 to a glass or silicon wafer 20. Substrate 18 includes a cavity 22 such that when substrate 18 is bonded to wafer 20, wafer 20 seals cavity 22. Cavity 22 is positioned directly below micro-machine element 54. In one embodiment, wafer 20 hermetically seals cavity 22 so that pressure sensor die 10 is an absolute pressure sensor.
FIG. 1B shows another embodiment of a pressure sensor die 10B, which includes a die hole 60 through wafer 20 to vent cavity 22 making pressure sensor die 10B a differential pressure sensor. As discussed in more detail below, the method and structure of the present invention works equally well with both absolute pressure sensors, such as pressure sensor die 10, and differential pressure sensors, such as pressure sensor die 10B.
Pressure sensor die 10 or 10B is typically used to monitor the pressure of an external fluid, i.e., a gas or liquid, by placing first or outer surface 56 of pressure sensor die 10 or pressure sensor die 10B, including micro-machine element 54, in contact with the external fluid. During normal operation of pressure sensor die 10 or 10B, micro-machine element 54 flexes in response to pressure on first or outer surface 56.
This flex is sensed by piezoresistors 14 and processed to determine the pressure exerted on first or outer surface 56 by the external fluid, i.e., the pressure of the liquid or gas.
The structure and operation of pressure sensors, such as pressure sensor die 10 and pressure sensor die 10B, is well known to those of skill in the art. Consequently, a more detailed discussion of the structure and operation of pressure sensor die 10 and pressure sensor die 10B is omitted here to avoid detracting from the present invention. However, it is worth noting here that, as discussed above, in order for pressure sensor die 10 or pressure sensor die 10B to function, first or outer surface 56, including micro-machine element 54 must be flexibly coupled to the surrounding environment and cannot be shielded from that environment by interposing layers of packaging material such as plastics or epoxies.
FIG. 1C is an enlarged cross-sectional view of a pressure sensor sub-assembly 100 including a pressure sensor die 110 mounted on a substrate 102 in die attach region 131. Like pressure sensor die 10 of FIG. 1A, pressure sensor die 110 (FIG. 1C) includes a pressure sensitive micro-machine element 154 composed of a portion of the epitaxial silicon layer 116. Like pressure sensor die 10 discussed above, pressure sensor die 110 is formed by bonding a substrate 118 to a glass or silicon wafer 120. Substrate 118 includes a cavity 122 such that when substrate 118 is bonded to wafer 120, wafer 120 seals cavity 122. Cavity 122 is positioned directly below micro-machine element 154.
Pressure sensor die 110 is attached to a first surface 111 (a die attach surface) of substrate 102 in die attach region 131 using any one of several well-known adhesives 104. Substrate 102 is typically a printed circuit board (PCB). In one embodiment, electrically conductive contacts or pads 106 on first or outer surface 130 of pressure sensor die 110 are connected with electrically conductive bond wires 103 to electrically conductive traces 112 and/or electrically conductive regions (not shown) formed on first surface 111 of substrate 102. Electrically conductive vias 114 are formed through substrate 102, from traces 112 and/or regions on first surface 111 to a second surface (the mounting surface) 140 of substrate 102 which is opposite first surface 111. Electrically conductive traces 113 formed on second surface 140 of substrate 102 extend to electrically conductive contact or pads 115 formed on second surface 140 of substrate 102. Electrically conductive contacts 115 are used to connect substrate 102 and pressure sensor die 110 to a larger system, such as a mother board (not shown), using well known methods such as solder balls, pins, leadless carrier chip (LCC) contacts or other surface mounts.
In accordance with the present invention, a plurality of pressure sensor die packages are fabricated simultaneously, in an array, to minimize the cost associated with each individual pressure sensor die package.
In one embodiment of the invention, a plurality of pressure sensor dice are attached to an array of pressure sensor die sites located on a substrate. The pressure sensor dice are then electrically connected to the pressure sensor die sites using, in one embodiment, standard wire bond techniques.
The resulting array of pressure sensor die sub-assemblies is then molded, in one embodiment of the invention, using a mold tool that closes on three sides of the substrate so that a cavity is formed that is open on the fourth side. To this end, a first portion of the molding tool has a plurality of insert pins that close on the outer surface of each pressure sensor die.
As a result, using the method of the invention, a portion of the outer surface of the micro-machine element of each pressure sensor die is left exposed at the bottom of a cavity in the molding encapsulant. After molding, the exposed outer surface of the micro-machine element is covered with a pressure coupling gel that is applied in the shallow cavity. The coupling gel protects micro-machine elements from the environment, yet is compressible and is capable of coupling pressure from the external environment to the micro-machine elements.
The resulting array of packaged pressure sensor dice are then sigulated using well known sawing or laser techniques or by snapping a specially formed snap array.
In another embodiment of the invention, a hole is formed in the array substrate and the pressure sensor substrate to accommodate a differential pressure sensor die.
In another embodiment of the invention, a custom substrate is formed with a plurality of holes formed, one each, at pressure sensor die mounting sites. A plurality of pressure sensor dice are then attached to pressure sensor die mounting sites located on the substrate. The pressure sensor dice are then electrically connected to the pressure sensor sites using, in this embodiment, standard flip-chip techniques.
The resulting array of pressure sensor die sub-assemblies is then molded, using a mold tool that closes on the substrate and is filled with encapsulant.
Using this embodiment of the method of the invention, a portion of the outer surface of the micro-machine element of each pressure sensor die is left exposed at the bottom of the holes in the substrate. After molding, the exposed outer surface of the micro-machine element is covered with a pressure coupling gel applied in the hole in the substrate. The resulting array of packaged pressure sensors are then sigulated using well known sawing or laser techniques or by snapping a specially formed snap array.
In another embodiment of the invention, a cavity is formed in the encapsulant and the pressure sensor substrate to accommodate a differential pressure sensor die.
In particular, one embodiment of the method of the invention includes: providing a pressure sensor die, the pressure sensor die having a pressure sensor die first surface and a pressure sensor die second surface, opposite the pressure sensor die first surface; providing a substrate, the substrate having a substrate first surface and a substrate second surface, opposite the substrate first surface, the substrate first surface having a die attach region; attaching the pressure sensor die second surface to the substrate first surface in the die attach region; and applying encapsulant to the substrate first surface and the pressure sensor die, the encapsulant having an outer surface, the encapsulant being applied such that the encapsulant forms a cavity over a first region of the pressure sensor die first surface, the cavity having side surfaces and a bottom surface wherein the first region of the pressure sensor die first surface is the bottom surface of the cavity and the first region of the pressure sensor die first surface is not covered by the encapsulant.
One embodiment of the method of the present invention also includes filling at least a portion of the cavity in the encapsulant with coupling gel such that the coupling gel covers the first region of the first surface of the pressure sensor die.
These and other features and advantages of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings. | {
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A popular way of accessing television programming is by way of a satellite broadcast receiver and small attached dish antenna designed to receive television video and audio data received from a satellite uplink center by way of an orbiting satellite. By accessing such a system, a subscriber to a satellite broadcast service provider may receive any of several hundred programming channels providing news, sports, entertainment, and the like for live program viewing, or for recording of programs for subsequent playback at a time more convenient for the subscriber.
Oftentimes, a satellite broadcast receiver provides an additional communication connection, such as a telephone line connection, thus allowing the subscriber to request programming services, such as special events and video-on-demand (VOD) or pay-per-view (PPV) programs, by way of the broadcast receiver. This additional communication connection thus allows the subscriber to contact the satellite uplink center. Such communication is generally not possible by way of the satellite connection, as the broadcast receiver and associated antenna are not designed to transmit information back to the uplink center via satellite.
In addition to delivering broadcast programming, a satellite broadcast service provider may also employ the satellite uplink center and satellite to send control information to the broadcast receiver. Such control information may include, for example, authorization and deauthorization information regarding which, if any, of the programming channels the broadcast receiver is to be configured to receive and present to the subscriber. Such information may be based on the level of service for which the subscriber pays. However, the broadcast receiver may not receive some portion of the information from time to time due to various circumstances, such as poor atmospheric conditions or the receiver being powered down during the transmission of the control information. As a result, the uplink center may transmit this information multiple times by way of the satellite to the broadcast receiver over a number of hours to help ensure that the information is ultimately received at the broadcast receiver. | {
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1. Field of the Invention
The present invention relates to a light-emitting element driving circuit, and in particular, to a light-emitting element driving circuit which changes brightness of a light-emitting element.
2. Description of the Related Art
In recent years, there are more occasions where a video image such as one-segment broadcasting is viewed on a main liquid crystal display of a portable phone, and a light-emitting element driving circuit which changes the brightness of the backlight of the liquid crystal is sometimes equipped in the portable phone. The light-emitting element driving circuit applies an automatic adjustment of the brightness of the backlight of the liquid crystal corresponding to the ambient luminosity, in order to optimize the visibility. More specifically, the light is adjusted such that the brightness of the backlight is increased to achieve brighter display when the ambient environment is bright and the brightness of the backlight is reduced to achieve darker display when the ambient environment is dark, so that the visibility is optimized. JP 2005-310854 A discloses a driving circuit which applies brightness adjustment of a light-emitting element.
In addition, a main liquid crystal screen is provided on a portable phone, and when a key button or the like of the portable phone is operated when the main liquid crystal screen is viewed, the backlight is set in the high brightness (normal mode) and a bright screen is achieved. When a state of no operation is continued, the main liquid crystal screen is automatically set to the low brightness (slight emission mode) and a dark screen is realized, to inhibit the current consumption. JP 2005-310854 A discloses a drive circuit which applies brightness adjustment of a light-emitting element.
Moreover, as described above, because there are more occasions where an video image such as one-segment broadcasting is viewed on the main liquid crystal display of the portable phone, a light-emitting element driving circuit which changes brightness of the backlight of the liquid crystal is sometimes equipped in the portable phone. In the light-emitting element driving circuit, a control to change the brightness of the backlight of the liquid crystal according to content of the video image signal is applied in order to display a clear image with a superior contrast. More specifically, the light is adjusted such that a bright image is displayed brighter with the brightness of the backlight increased and a dark image is displayed darker with the brightness of the backlight reduced. JP 2005-310854 A discloses a driving circuit which applies brightness adjustment of the light-emitting element.
However, when the current value of current flowing through the backlight is increased in order to increase the brightness of the backlight corresponding to the ambient environment becoming brighter, a forward voltage (Vf)) of the backlight is increased, and the terminal voltage of the cathode terminal of an LED forming the backlight is reduced. When the terminal voltage of the cathode terminal is reduced to a value less than a set voltage, a voltage boosting circuit is activated to boost the terminal voltage of the anode terminal. However, there may be cases where, after the voltage is once boosted, for example, the ambient environment becomes darker, the current value of the current flowing in the backlight is reduced in order to reduce the brightness of the backlight, and the forward voltage (Vf)) of the backlight is reduced. In such a case, although the terminal voltage of the cathode terminal of the LED is increased, the voltage boosting circuit may still be in an operating state, and consequently, a wasteful current consumption is caused.
Moreover, during the normal mode, the brightness is high. When the current value of the current flowing in the backlight is increased in order to increase the brightness of the backlight, the forward voltage (Vf)) of the backlight is increased, and the terminal voltage of the cathode terminal of the LED forming the backlight is reduced. Similar to the above, when the terminal voltage of the cathode terminal is reduced to a value less than the set voltage, the voltage boosting circuit is activated and the terminal voltage of the anode terminal is boosted. However, there may be cases where, after the voltage is once boosted, for example, the device is set in the slight emission mode (low brightness), the current value of the current flowing in the backlight is reduced in order to reduce the brightness of the backlight, and the forward voltage (Vf)) of the backlight is reduced. In such cases, if the voltage boosting circuit is in the operating state even after the terminal voltage of the cathode terminal of the LED is increased, wasteful current consumption is caused.
Furthermore, when the brightness is increased for a bright image, the current value of the current flowing in the backlight is increased in order to increase the brightness of the backlight, the forward voltage (Vf) of the backlight is increased, and, consequently, the terminal voltage of the cathode terminal of the LED forming the backlight is reduced. Again, when the terminal voltage of the cathode terminal is reduced to a value less than the set voltage, the voltage boosting circuit is activated to boost the terminal voltage of the anode terminal. However, there may be cases where, after the voltage is once boosted, for example, the brightness is reduced for a dark image, the current value of the current flowing in the backlight is reduced in order to reduce the brightness of the backlight, and the forward voltage (Vf) of the backlight is reduced. In such cases, if the voltage boosting circuit is in the operating state even after the terminal voltage of the cathode terminal of the LED is increased, wasteful current consumption is caused. | {
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Oil and gas wells are typically drilled with a rotary drill bit, and the resulting borehole is cased with steel casing cemented in the borehole to support pressure from the surrounding formation. Hydrocarbons may then be produced through smaller diameter production tubing suspended within the casing. Although fluids can be produced from the well using internal pressure within a producing zone, pumping systems are commonly used to lift fluid from the producing zone in the well to the surface of the earth. This is often the case with mature producing fields where production has declined and operating margins are thin.
The most common pumping system used in the oil industry is the sucker rod pumping system. A pump is positioned downhole, and a drive motor transmits power to the pump from the surface with a sucker rod string positioned within the production tubing. Rod strings include both “reciprocating” types, which are axially stroked, and “rotating” types, which rotate to power progressing cavity type pumps. The latter type is increasingly used, particularly in wells producing heavy, sand-laden oil or producing fluids with high water/oil ratios. The rod string can consist of a group of connected, essentially rigid, steel or fiberglass sucker rod sections or “joints” in lengths of 25 or 30 feet. Joints are sequentially connected or disconnected as the string is inserted or removed from the borehole, respectively. Alternatively a continuous sucker rod (COROD) string can be used to connect the drive mechanism to the pump positioned within the borehole.
A number of factors conspire to wear down and eventually cause failure in both sucker rods and the production tubing in which they move. Produced fluid is often corrosive, attacking the sucker rod surface and causing pitting that may lead to loss of cross-sectional area or fatigue cracking and subsequent rod failure. Produced fluid can also act like an abrasive slurry that can lead to mechanical failure of the rod and tubing. The rod and tubing also wear against each other. Such wear may be exacerbated where the well or borehole is deviated from true vertical. Even boreholes believed to have been drilled so as to be truly vertical and considered to be nominally straight may deviate considerably from true vertical, due to factors such as drill bit rotational speed, weight on the drill bit, inherent imperfections in the size, shape, and assembly of drill string components and naturally-occurring changes in the formation of the earth that affect drilling penetration rate and direction. Also, some boreholes are intentionally drilled at varying angles using directional drilling techniques designed to reach different parts of a hydrocarbon-producing formation. As a result, sucker rods and production tubing are never truly concentric, especially during the dynamics of pumping, and instead contact one another and wear unpredictably over several thousand feet of depth. Induced wear is therefore a function of many variables, including well deviation from true vertical; angle or “dogleg” severity; downhole pump operating parameters; dynamic compression, tensile and sidewall loads; harmonics within the producing sucker rod string; produced solids; produced fluid lubricity; and water to oil ratio. Additionally, in certain conditions, such as in geologically active areas or in areas of hydrocarbon production from diatomite formations, wellbores may shift over time, causing additional deviation from vertical.
Boreholes deviate considerably from true vertical due to various factors, including drill bit rotational speed, weight on the drill bit, inherent imperfections in the size, shape, and assembly of drill string components and naturally-occurring changes in the formation of the earth. When using a tubing anchor to rigidly fix the lower part of a tubing string in a wellbore relative to the casing, it is often necessary to apply a tensile load to the tubing string to prevent sags or kinks in the tubing in certain zones of the wellbore. In certain conditions, such as in geologically active areas or in areas of hydrocarbon production from diatomite formations, producing wells may shift over time, causing additional deviation from vertical. As a result, sucker rods and production tubing are often never truly concentric, especially during the dynamics of pumping, and instead contact one another and wear in certain areas, some of which are known as “doglegs”, or where the tubing sags or is kinked. Without a continuous deviation survey of the wellbore, it is difficult, if not impossible, to identify areas where the well deviation from vertical results in contact and wear of the rods and tubing.
For many years it has been possible to determine the deviation of a borehole, or wellbore, from true vertical. Such techniques are used extensively in the drilling of new wellbores, either as periodic “single shot” surveys, “multishot” surveys or even continuously while drilling, known as “MWD”. U.S. Pat. No. 6,453,239 to Shirasaka, et al, U.S. Pat. No. 5,821,414 to Noy, et al, U.S. Pat. No. 4,987,684 to Andreas, et al and U.S. Pat. No. 3,753,296 to Van Steenwyk, disclose such examples of surveying wellbores. However, in the case of most existing rod-pumped oil wells, any such surveys performed during the original drilling of the well largely comprised periodic surveys of wellbore direction and inclination performed only at one or two key intervals during the well-drilling operation. Consequently, a continuous profile of the wellbore deviation, giving rise to tubing and rod wear, is not generally known. Alternatively, performing a dedicated, continuous directional survey of existing wellbores, such as those contemplated in the above patents, is generally cost-prohibitive. There is a need for a cost-effective directional survey that can be integrated into well work-over operations of existing producing wellbores to obtain an accurate, nearly continuous deviation profile and allow mitigation of rod and tubing wear.
Prior art wellbore deviation techniques and tools are generally designed for the measurement of a wellbore while drilling, or are used on wireline or slickline during the process of drilling, to measure the direction and inclination of the wellbore with respect to an as-yet un-reached planned trajectory or target of interest. Prior art accelerometer and magnetometer deviation tools are also typically capable of determining wellbore inclination and azimuth only outside of the presence of magnetic interference, e.g., in open, uncased wellbores.
Oil well production string inspection methods conventionally use magnetic flux leakage techniques and typically rely only upon signal amplitude and time-based denominations or, in some cases, signal amplitude and wellbore depth, to provide the equipment operator with information representing the sucker rod or tubing string condition. U.S. Pat. Nos. 2,555,853, 2,855,564, 4,492,115, 4,636,727, 4,715,442, 4,843,317, 5,914,596, 6,316,937 disclose methods and apparatus to perform magnetic flux leakage inspections of sucker rods and tubing as elements of the production wellbore.
The amplitude of a magnetic flux leakage signal from a flaw in a ferromagnetic material under test is a function of many variables, including magnetic permeability of the material under test; magnetizing field strength; detection sensor type; sensor-to-material-under-inspection stand-off; flaw orientation relative to magnetic field direction; flaw volume; flaw depth, flaw shape; sensor-to-material-under-inspection relative velocity; sensor signal filtering and; sensor signal-to-noise ratio, among others. Conventional systems that rely only upon amplitude and time, or upon amplitude and wellbore depth, are susceptible to misinterpretation since the apparent flaw signal amplitude may be a function of many factors other than depth alone. Many such systems do not employ field standardization techniques to establish flaw standardization levels for inspection. Even those methods that do employ standardization techniques rely upon signal amplitude alone for flaw severity analysis.
Some prior art gyroscope and accelerometer deviation tools, of either the gimballed or strapped-down type, are capable of use inside cased hole and are generally used during the drilling process. U.S. Pat. No. 4,468,863 discloses a single shot or periodic multi-shot survey tool deployed on a wireline. U.S. Pat. No. 5,821,414 discloses a system for measuring deviation and inclination, while a wellbore is being drilled, to achieve an ultimate bottom hole location that positions the wellbore to optimally drain the target hydrocarbon reservoir. Most Measurement-While-Drilling applications that are intended for open hole, high temperature, high pressure environments, as disclosed in U.S. Pat. No. 6,714,870 to Weston, et al. Such tools are typically large, insulated, shock-absorbing, high pressure- and temperature-resistant to handle the extremely demanding environment of drilling in extreme temperature, vibration and pressure, as disclosed in U.S. Pat. No. 4,302,886. Systems may utilize relatively gimbaled gyroscopes or expensive and complex Coriolis-effect strapped-down gyroscopes, as disclosed in U.S. Pat. No. 6,453,239. Such tools are generally too large and lengthy to be used inside small diameter production tubing, and too expensive for most pumped well application. The high cost of these systems prohibits consideration by the operators of relatively shallow, existing rod-pumped, producing wells in the declining fields of mature sedimentary basins.
Failure of pumped oil wells due to the cumulative effect of the wear of sucker rods on tubing and such wear combined with corrosion is considered to be the single largest cause of well down time. Generally accepted methods of mitigating such wear include installing rod guides to centralize the sucker rod in the tubing with selected tubing surface contact materials; sinker bars to add weight to the sucker rod string; tubing insert liners composed of wear-resistant materials such as nylon and polythene; and improving operational practice. Examples of rod guides are disclosed in U.S. Pat. No. 6,152,223 to Abdo, U.S. Pat. No. 5,339,896 to Hart, U.S. Pat. No. 5,115,863 to Olinger, and U.S. Pat. Nos. 5,492,174 and 5,487,426 to O'Hair. An example of a tubing liner insert is U.S. Pat. No. 5,511,619 to Jackson. Since many of these mitigation techniques are expensive to apply, oil well operators must carefully assess the economics of any such mitigation techniques.
Although wear can be mitigated, it cannot be eliminated, so inspection of sucker rods and production tubing are common in the industry. Well operators within the industry commonly follow a “run until failure” approach, only inspecting components upon failure of some element of the wellbore, which may include a hole or split in the tubing, pump failure, rod failure, or tubing separation. The nature of the industry is that down-time is costly, both in terms of lost or deferred production and the actual cost to repair the failure by work-over of the wellbore. Another reason well operators are reluctant to perform inspections at regular intervals is that the diagnostic capabilities of current inspection practices are somewhat limited. A more useful, reliable, and economical method of wear and corrosion pattern analysis and diagnosis that gives rise to mitigation opportunities would allow operators to be more proactive. Further, many operators are unable to devote the time and human resources to perform the necessary analysis of data such as well deviation, rod failure and tubing failure.
The most basic wear analysis techniques include simply observing the wear patterns contained within the individual lengths of oil well production tubing, to empirically inspect tubing for wall thickness loss due to mechanical wear and corrosion of sucker rods and tubing. Caliper surveys are available to measure the inside diameter of production tubing but cannot examine the condition of the outside condition of the tubing.
More sophisticated inspection techniques employ magnetic sensor technologies to assess the condition of production tubing. Magnetic testing devices have been known for many years, as disclosed in U.S. Pat. No. 2,555,853 to Irwin and more specifically for oilfield tubulars and sucker rods in U.S. Pat. No. 2,855,564 to Irwin for a Magnetic Testing Apparatus and Method. Applying this technology to the inspection of oilfield tubulars, U.S. Pat. Nos. 4,492,115, 4,636,727 and 4,715,442 disclose tubing trip tools and methods for determining the extent of defects in continuous production tubing strings during removal from the well. The tools and methods include magnetic flux leakage sensor coils and Hall effect devices for detecting defects such as average wall thickness, corrosion, pitting, and wear. One or more of the above tools further include a velocity and position detector for correlating the location of individual defects to their locations along the tubing string. A profile of the position of the defects in the continuous string can also be established.
U.S. Pat. No. 4,843,317 to Dew discloses a method and apparatus for measuring casing wall thickness using an axial main coil for generating a flux field enveloping the casing wall. U.S. Pat. No. 6,316,937 to Edens discloses a combination of magnetic Hall effect sensors and digital signal processing to evaluate defects and wear. U.S. Pat. No. 5,914,596 to Weinbaum discloses a magnetic flux leakage and sensor system to inspect for defects and measure the wall thickness and diameter of continuous coiled tubing. All of these systems induce magnetic flux within the tubing. Surface defects result in magnetic flux leakage. Sensors measure the leakage and are thereby used to locate and quantify the surface defect.
Techniques are also known for magnetically inspecting sucker rods. Conventional sucker rod segments are commonly removed from an oil well, separated, and trucked to inspection plants to be “reclaimed”. U.S. Pat. No. 2,855,564 to Irwin discloses a magnetic testing apparatus used in inspection of sucker rods, and U.S. Pat. No. 3,958,049 to Payne discloses an example of a process for reclaiming used sucker rod. In the latter patent, the salvaged rod is degreased, visually inspected, subjected to a shot peening operation, and analyzed for structural imperfections. Magnetic induction techniques are employed, albeit at an inspection plant, rather than on-site. A system for evaluating a coiled sucker rod string, or “COROD”, as it is pulled from a well is disclosed in U.S. Pat. No. 6,580,268. Defects within the COROD may be correlated with their position. The system generates “real time” calculated dimensional display of the COROD and cross-sectional area as a function of position. Wireless technology can be used, such as to convey signals from a processor unit as many as 200 feet to a laptop server.
Aspects of the sucker rod and production tubing inspection techniques discussed above have a certain level of sophistication, such as the use of wireless technology and digital signal processing. Ironically, however, the analyses derived from the resulting data are relatively limited and shortsighted. The data obtained is not optimally used to correct or mitigate wear. For example, the end result of conventional sucker rod inspection and reclamation is the rather simplistic determination of whether to re-classify and reuse or dispose of each rod.
Additionally, because the production tubing in most rod-pumped producing wells is tubing that has previously been used in other wells or from such reclaimed supplies, pre-existing wear patterns on tubing alone are often misleading as to the root causes of tubing wear in the current wellbore. Further, even a detailed, positional analysis of defects does not provide an adequate window as to their root cause or mitigation. For example, in general, well operators simply reposition rod guides, which may merely shift wear on the rod or tubing to another position along the string. An alternative technique to mitigate rod wear on tubing is disclosed in U.S. Pat. No. 36,362E to Jackson, whereby an abrasion resistant polymer, such as polyethylene, is inserted into the tubing. This technique, however, reduces the inside diameter of the tubing and does not assess the cause of tubing wear. As a result, the polythene liner may simply fail over time, rather than the tubing, which still necessitates work-over. Not even “real time” data reports provide an adequate solution to mitigating wear, because they do nothing to improve the quality or scope of the analysis, or correlate tubing condition information with rod condition information. An accurate analysis of the cause of wellbore failure due to tubing or rod failure is also aided with a profile of the wellbore deviation.
Another problem with existing inspection systems is that there is no available means of performing these assessments in a cost-effective and timely manner so that tubing wear can be mitigated through an economical solution specific to a well. Because quickly returning the well to production is of paramount importance, full analysis of any limited information available is often difficult, if not impossible, to perform before the well is returned to production.
The disadvantages of the prior art are overcome by the present invention. An improved system is provided for evaluating and mitigating one or more of wear and corrosion on rod strings and/or tubular strings while being pulled from a wellbore. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Disclosure
This disclosure relates generally to drill bits and systems that utilize same for drilling wellbores.
2. Background of the Art
Oil wells (also referred to as “wellbores” or “boreholes”) are drilled with a drill string that includes a tubular member having a drilling assembly (also referred to as the “bottomhole assembly” or “BHA”). The BHA typically includes devices and sensors that provide information relating to a variety of parameters relating to the drilling operations (“drilling parameters”), behavior of the BHA (“BHA parameters”) and parameters relating to the formation surrounding the wellbore (“formation parameters”). A drill bit attached to the bottom end of the BHA is rotated by rotating the drill string and/or by a drilling motor (also referred to as a “mud motor”) in the BHA to disintegrate the rock formation to drill the wellbore. A large number of wellbores are drilled along contoured trajectories. For example, a single wellbore may include one or more vertical sections, deviated sections and horizontal sections through differing types of rock formations. When drilling progresses from a soft formation, such as sand, to a hard formation, such as shale, or vice versa, the rate of penetration (ROP) of the drill changes and can cause (decreases or increases) excessive fluctuations or vibration (lateral or torsional) in the drill bit. The ROP is typically controlled by controlling the weight-on-bit (WOB) and rotational speed (revolutions per minute or “RPM”) of the drill bit so as to control drill bit fluctuations. The WOB is controlled by controlling the hook load at the surface and the RPM is controlled by controlling the drill string rotation at the surface and/or by controlling the drilling motor speed in the BHA. Controlling the drill bit fluctuations and ROP by such methods requires the drilling system or operator to take actions at the surface. The impact of such surface actions on the drill bit fluctuations is not substantially immediate. Drill bit aggressiveness contributes to the vibration, oscillation and the drill bit for a given WOB and drill bit rotational speed. Depth of cut of the drill bit is a contributing factor relating to the drill bit aggressiveness. Controlling the depth of cut can provide smoother borehole, avoid premature damage to the cutters and longer operating life of the drill bit.
The disclosure herein provides a drill bit and drilling systems using the same configured to control the aggressiveness of a drill bit during drilling of a wellbore. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention relates generally to processes for preparing bis(ether anhydrides). In particular, safer and more efficient imidization, nitration, displacement and exchange reactions leading to the preparation of bis(ether anhydrides) are made possible as a result of conducting the imidization step with a liquid alkylamine wherein the alkyl group of the alkylamine preferably contains at least three carbon atoms.
2. Brief Description of the Background Art
Processes for preparing bis(ether anhydrides) are well known. Bis(ether anhydrides) are intermediates used to prepare polyetherimides which are well known components for plastic automobile parts and the like. Biphenol dianhydride and bisphenol A dianhydride are two frequently used intermediates. Processes for preparing such bis(ether anhydrides) can involve four intermediate steps. Those process steps comprise:
(1) an imidization step in which "make-up" n-alkyl phthalimide is synthesized from an alkylamine and phthalic anhydride,
(2) a nitration step in which the n-alkyl phthalimide is nitrated,
(3) a displacement reaction step in which the nitro substituent on the phthalimide ring is displaced and a bisimide is formed, and
(4) a transformation step ("exchange reaction") in which the bisimide is transformed to dianhydride, preferably by reacting the bisimide with phthalic anhydride in the presence of triethylamine and water. The exchange also can be carried out by a process in which the bisimide is hydrolyzed, acidified and dehydrated to form the desired bis(ether anhydride). The resulting product can then be employed to prepare polyetherimides such as ULTEMO polyetherimides commercially available from General Electric Co. See, for example, U.S. Pat. No. 4,020,089 to Markezich (imidization); U.S. Pat. Nos. 4,902,809 to Groenaweg et al. and 4,599,429 to Odle (nitration); U.S. Pat. No. 4,257,953 to Williams, III et al. (displacement); and U.S. Pat. Nos. 3,957,862 and 3,879,428, both to Heath et al. (exchange reaction).
As with many commercial chemical synthesis processes, there remains a need and desire to improve the process from economic, environmental and overall efficiency aspects. We have specifically identified the use of methylamine in the preparation of the "make-up" phthalimide as an aspect of the existing process that, if avoided, could lead to process improvements.
The disadvantage presented by methylamine is twofold. Methylamine is not only toxic, but also its boiling temperature is relatively low, therefore rendering it gaseous at temperatures under which make-up phthalimide is synthesized. As a result, methylamine requires special toxic gas equipment when preparing the "make-up" phthalimide. In addition, at least two condensers are typically employed to condense methyl phthalimide to its more practical liquid form. The liquid condensate which forms in the condenser, however, solidifies on the walls of the condenser and creates blockages. As a result, the condenser is taken off stream and another condenser is utilized while the blocked condenser is heated to remove the residue. The second condenser is similarly removed once it becomes blocked. A safer and more efficient process thus is desired.
In addition, the resulting methyl-derived phthalimide has a high melting temperature and thus must be stored at temperatures of about 133.degree. C. or higher in order to keep the "make-up" phthalimide in liquid phase for further processing.
The overall efficiency of nitrating methyl phthalimide is relatively low because recycling the methyl phthalimide nitrating agent requires a relatively inefficient nitration concentration system. After nitrating the phthalimide ring to form a methylnitrophthalimide, the nitrophthalimide product and the nitrating agent are recovered. N-methyl nitrophthalimide usually is recovered by removing the nitrating agent and solvent via a falling film evaporator. A falling film evaporator, however, is only capable of concentrating N-methyl nitrophthalimide to about 50% solids. Attempts to remove any more nitric acid results in the precipitation of the methylnitrophthalimide product from the solution. As a result, methylnitrophthalimide reaction product solution is quenched into weak nitric acid. The resulting precipitate is washed in countercurrent fashion on a belt filter. In order to be recycled for later nitration, the remaining dilute nitric acid must be recovered in a nitric acid concentrator and sulphuric acid concentrator (NAC/SAC) system. Both the belt filter and NAC/SAC system are quite inefficient as they employ about two pounds of water for every one pound of methylnitrophthalimide produced.
The N-methyl nitrophthalimide product then is dried by partitioning the product from water into toluene. Handling environmentally hazardous organic solvents thus is required. Organic solvents also are required in the displacement reaction which forms the bisimide.
Further problems and inefficiencies are presented when extracting the by-products created by the displacement reaction of methylnitrophthalimides with the salts of sodium bisphenol. These byproducts typically are extracted at temperatures of about 85.degree. C. using alkali solutions at concentrations of about 1 to about 5% alkali. Extractions with such solutions can cause hydrolysis of the desired bisimide product, and as a result, the time, temperature and alkali concentration must be monitored in order to minimize such hydrolysis.
Displacement reactions with N-methyl nitrophthalimides also can be carried out to only about a 22% solids level in the bisimide reaction mixture. If the reaction is allowed to run to a higher solids level, bisimide product precipitates out of the solvent. In addition, substantial amounts of organic solvents are required for processing mixtures at these levels of solids. Running this reaction to a higher, and thus more efficient, solids level thus is difficult and limited.
Inefficiencies also occur in the exchange reaction with bisimides derived from methyl amines. The reaction influent of the preferred exchange reaction comprises bisimide and excess phthalic anhydride and triethylamine, as well as the accompanying transimidization products of both reactants, e.g., bisimide, imide acid, diacid, phthalic acid, and N-methyl phthalimide. By-products typically are removed by extracting the imide products into toluene, thereby driving the equilibrium and leaving only tetra acid salts in the aqueous phase. These acid salts then are stripped of water and triethylamine to leave the desired dianhydride. Methyl-derived bisimides, however, have a limited solubility in toluene, and, therefore, throughput of reaction product solids in the exchange reaction of these bisimides is low, e.g., about 12%. Greater efficiency is desired. | {
"pile_set_name": "USPTO Backgrounds"
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Exhaust systems are widely known and used with combustion engines. Typically, an exhaust system includes exhaust tubes that convey hot exhaust gases from the engine to other exhaust system components, such as mufflers, resonators, etc. Mufflers and resonators include acoustic chambers that cancel out sound waves carried by the exhaust gases. Although effective, these components are often relatively large in size and provide limited nose attenuation.
Attempts have been made to improve low frequency noise attenuation by either increasing muffler volume or increasing backpressure. Increasing muffler volume is disadvantageous from a cost, material, and packaging space perspective. Increasing backpressure can adversely affect engine power.
Another solution for reducing low frequency noise is to use a passive valve assembly. One disadvantage with a traditional passive throttling valve configuration is a phenomena referred to as “flutter.” Valve flutter is associated with pressure fluctuations (pressure pulses) as the passive valve begins to open, i.e. moves from a fully closed position toward an open position.
The passive valve includes a flapper valve body or vane that is positioned within the exhaust pipe, with the vane being pivotable between open and closed positions. The closed position comprises a start position for the valve where the valve body is orientated to be perpendicular to an exhaust gas flow direction. The passive valve is spring biased toward the closed position and includes a valve top to define a rest/closed position for the valve. When exhaust gas pressure is sufficient to overcome this spring bias, the vane is pivoted toward the open position.
Valve flutter results when the pressure that contributes to the opening of the valve is decreased as the valve opens. The decrease in pressure can contribute to a reduction in valve opening force, leading to the spring biasing force returning the valve to the closed position. A subsequent pressure pulse (an increase in pressure subsequently followed by a decrease in pressure) results in the flapper valve body beginning to open in response to the increase in pressure immediately followed by closing movement in response to the decrease in pressure. When a series of these pressure pulses are generated, such as when the engine is operating a low speeds for example, the valve “flutters” back and forth between opening and closing. This can result in undesirable noise generation as the flapper valve body impacts the valve stop during each closing movement. Further, these multiple impact events can cause pre-mature wear on the valve body. | {
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This invention relates generally to RFID transponder systems and more particularly for disabling devices and methods of use for selectively disabling RFID transponders when desired.
In response to the inability of conventional toll collection means to meet the demands created by increased highway traffic, automated toll facilities that provide improved toll collection methods and systems have been proposed and are being implemented. These electronic toll collection systems eliminate the manual transactions of conventional toll collection means through the use of radio transmitters and receivers that perform the necessary transactions as a vehicle travels through the automated toll booth. For example, U.S. Pat. No. 7,224,291 (Hassett), which is assigned to the same assignee as this invention, discloses a system for automatic collection of tolls includes an in-vehicle toll processor (e.g., an RFID transponder or tag) having memory for storing a toll-money-available quantity purchased by the user, and a toll-facility-identification site that transmits a toll-facility-identifier signal indicating the identity of the upcoming toll facility. As the vehicle approaches the identification site, the in-vehicle processor receives the identifier signal and calculates the toll to be debited. When the vehicle passes through the toll facility, the in-vehicle processor transmits its identity, its net balance and the toll, which it debits from an account balance. The in-vehicle processor may increment a low balance, in which case it transmits information which is relayed to a central system for billing. Various means for shutting down delinquent in-vehicle components or identifying offender vehicles are described.
In some electronic toll collection applications, it is desirable to disable or temporarily degrade the performance of an RFID tag so that it cannot be read by an interrogating reader. One such situation can occur when more than one RFID tag is mounted in a vehicle windshield, and it is desired to read or write to one tag while preventing any interference from the other. This can occur during RFID system testing, or on actual vehicles that travel interstate highways and are forced to use different tags for various toll roads along the way. Another application is a toll road with high occupancy toll (HOT/HOV) lanes. There may be times where it would be desirable to temporarily disable an RFID tag, such as a windshield sticker tag, such that no toll is paid when traveling through a toll plaza. A person driving in the HOT/HOV lane that had someone else or others in the vehicle with them would be allowed by the toll authority to travel on the toll road without paying tolls. If a person was alone and wanted to drive in the HOT/HOV lane, they too would be allowed, but would have to pay tolls, and therefore would not be allowed to use the tag disabling device.
In the past, RFID tags that were mounted to windshields using hook and loop, or suction cups, or other releasably securable means that allowed easy removal and re-installation of the tags, were disabled by removing them from the windshield and placing them in a metallized bag, pouch or box. For example, the State of New Jersey makes use of “EZPass” RFD tags for its electronic toll collection system. As part of that system the State provides a “silver” (e.g., metallized) “read prevention bag” for users of the EZPass tag. Such users are instructed to insert the tag into the bag for situations where the tag is not to be read at a particular toll plaza. The placement of the tag within that bag will prevent the RFID tag from being read or written to by an interrogating system by shielding the tag from RF energy that the interrogator transmits. In particular, the bag or pouch reflects most or all of this energy, thereby cutting off communication between the tag and the reader. The disadvantage of this type of tag disabling method is that the tag has to be removed from the windshield to accomplish it.
The prior art includes other instances where an RFID transponder can be temporarily shielded so that it cannot be read. For example, Emvelope, Inc. offers a device under the trademark Emvelope® that provides an insert for a wallet or billfold to form a Faraday cage to contain the wireless signals being emitted by RFID chips on cards in the wallet or billfold. Emvelope, Inc. also offers a similar device in the form of a cover for use with passports. Magellan's International also offers a product, which it calls an RFID Passport Wallet, that is arranged to hold and protect passports and credit cards by providing protective shield, so the RF data in the card/passport can only be accessed when the user opens his/her wallet at approved locations.
While the foregoing techniques for temporarily disabling or shielding RFID transponders are generally suitable for their intended purposes for their specific applications, such techniques are not suitable for temporarily disabling RFID transponders that are permanently affixed to a vehicle, e.g., sticker tags bearing RFID transponders secured to the inner surface of the vehicle's windshield or RFID transponders encapsulated in the windshield itself.
Recently, RFID ‘sticker’ tags have become increasingly popular, e.g., Transcore, Inc. provides such tags. These types of tags are less expensive, easier to use, easier to distribute and have more capability than the previous tags constructed of conventional printed circuit boards and housed in a plastic case. Another advantage is that the ‘sticker’ tags are designed to be permanently mounted and thus provide more security from fraud by preventing tags to be moved from one vehicle to another. The disadvantage of not being able to move tags between vehicles is offset by the lower cost so that an individual tag can be issued to each vehicle economically. A disadvantage of the permanently mounted ‘sticker’ tags, however, is that they can't be temporarily disabled. For example, once removed from the windshield, the adhesive on a windshield sticker tag, such as that produced by Transcore, Inc., can be damaged. Since the antenna design in this tag relies on uniform close proximity to the glass for proper operation, the tag cannot be reused. Thus, sticker tags and any other permanently mounted transponder would be read every time it passed within the RF field of an applicable interrogation system, even when the user did not desire to have the RFID tag read, e.g., to disable the tag when it was desired to pay using cash or other means.
RFID tags can be permanently disabled by mechanical destruction of the conductive patterns on the tag. An example is provided in U.S. Pat. No. 7,277,016 (Moskowitz et al.). While permanent tag disabling has certain viable applications, by definition it is unsuitable for applications where the tag is to be disabled only temporarily and so that it can be reused at some later time.
Accordingly a need exists for a device and method to temporarily disable sticker or other permanently mounted tags with the ease and simplicity as has characterized the temporary disablement of hard cased tags (e.g., by removal and placement in a remote location or in a shielding pouch so that the tag could not be read). A need also exists for a device and method for the temporary disablement of a permanently mounted tag to be controlled by the user of the tag without dismounting or damaging the tag. Further still, a need exists for enabling an RFID tag patron to use a permanently mounted RFID transponder, which is more secure than a removable transponder, but still has the flexibility to enable or disable operation of the RFID tag, as necessary.
The subject invention addresses those needs by providing ‘sticker’ tags and other permanently mounted RFID transducers with this same capability of temporary disablement while retaining all the other positive attributes of a permanently mounted tag/transponder. In particular, the subject invention provides a device for application to (e.g., mounting over) the sticker tag or any other RFID transponder fixedly mounted on the windshield or some other portion of the vehicle for the temporarily disabling the RFID transponder, wherein the disabling device is removable, reusable, and able to be stored within a vehicle without being damaged. In addition, the subject invention enables the patron to maintain privacy if so desired. | {
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FIG. 1 depicts a block diagram of telecommunications system 100 in the prior art. Telecommunications system 100 comprises telecommunications terminal 101, call server 102, local area network 103, internet protocol-based network 104, and web application server 105, interconnected as shown.
Telecommunications terminal 101 is capable of transmitting and receiving signals as part of a call on behalf of its user. It interacts with call server 102 to place outgoing calls and to receive incoming calls. Terminal 101 transmits via local area network 103 call-related traffic in packet format to one or more destinations, such as devices that are associated with Internet Protocol-based network 104. Terminal 101 also receives via local area network 103 call-related traffic in packet format from one or more sources, such as from devices that are associated with Internet Protocol-based network 104. Terminal 101 communicates by using the Internet Protocol set of rules and, as such, is an Internet Protocol-based telephone.
Terminal 101 is also capable of receiving and displaying Internet Protocol-based content, such as text and graphics, on a built-in display screen and by using a built-in browser. The user of terminal 101 uses the browser to request and display content, such as text and graphics, similarly to how a user of a personal computer uses the computer's browser (e.g., Internet Explorer™, Netscape Communicator™, etc.) to display content on the computer's screen. The user of terminal 101 requests the content by selecting objects on the display screen, which causes terminal 101 to transmit a request message to the source of the content, such as web application server 105. Subsequently, terminal 101 receives a message that contains the content, and the content is then displayed on the display screen.
The browser capability in terminal 101 is useful, in that it enables its user to navigate web applications, including information about the company, news, interactive applications (e.g., a conference room scheduler, etc.), company directory lookup, and so forth. It is the user who determines when to retrieve content; for example, if a call is in progress, the user will typically request content when the content will enhance the call or at a later time so as not to interfere with the call. It is disadvantageous, however, to rely on the user to determine the optimal time to retrieve content because doing so burdens the user rather than making it easier to use a browser-capable telecommunications terminal.
What is needed is a technique that mitigates some of the burden of retrieving content at a telecommunications terminal. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention relates to electronic signal modulation, and more specifically, to spread spectrum modulation of binary messages.
2. Description of Related Art
Many systems provide for a plurality of transmitter and receiver pairs, "communicating pairs", to communicate simultaneously with little or no interference between communicating pairs. This may be accomplished by allocating a different communication frequency to each communicating pair, known as frequency division multiple access (FDMA). There are situations in which it is difficult or impossible to assign each communicating pair a unique frequency. This occurs when there are simply too many communicating pairs close to each other on a designated bandwidth.
Another access method, such as time division multiple access (TDMA), may be employed, wherein each communicating unit is assigned a "time slice" in which to communicate on the same frequency band. This causes the "time slices" to become shorter as the number of communicating pairs increases.
Since both FDMA and TDMA communicate on narrowly defined bands, they are both susceptible to narrowband interference. Another method employs a spreading each message from each communicating pair across the entire usable bandwidth. They are all specially encoded such that they may be separated at the receiver. These are known as spread spectrum techniques.
Spread spectrum techniques are those modulation techniques which require a transmission bandwidth that far exceeds the message information bandwidth. The spread spectrum modulation characteristics should not depend upon the individual message to be transmitted as is the case with some other wideband modulation schemes such as wideband FM. There are many spread spectrum mechanisms. They can be conveniently classified as: (i) direct sequence, (ii) frequency hopping, (iii) time hopping, and (iv) hybrids.
In direct sequence spread spectrum modulation, a wideband carrier signal is combined with the relatively narrowband message to yield an encoded wideband signal. A typical digital implementation would be to create a high speed random binary sequence in having an equal probability of being a one or zero at any particular time. This high speed binary sequence is added to a binary message sequence. The addition is typically done by exclusive-ORing ("XOR") the two sequences together. The bits of the message sequence are much longer in duration than the bits from the high speed random source and thus many random bits are used per information bit. The random bits are often referred to as "chips" and the relationship between the random sequence rate and the message rate is such that an integral number of chips are used per message bit. The code used to "spread" the signal at the transmit unit, is required in "despreading" the signal at the receive unit.
There are many uses for direct sequence spread spectrum techniques. One primary use is that of spectrum sharing. It is possible for a number of different communicating pairs to occupy the same bandwidth simultaneously without significant mutual interference. This is usually accomplished in direct sequence spread spectrum systems by assigning each communicating pair a different spectrum spreading code. This is known in the art as code division multiple access (CDMA).
Since the messages are spread over a large bandwidth, there is less possibility of loss of communications due to narrow bandwidth interference. The effect of the interference is therefore reduced by the bandwidth over which it is applied.
Typically, one problem with direct sequence spread spectrum communications and CDMA is synchronization. In order to function properly, the receiver must generate a signal from the spreading code which is the inverse from the transmitted spread spectrum signal, and do so at the same rate as the transmit unit. The receive unit must also correct relative phase discrepancies between the transmit and receive unit. This requires synchronization to be established and maintained at a tolerance finer than a single chip width. Further, the receiver must know the particular spreading code employed by the transmit unit in order to decode the signal and recover the message.
Currently there is a need for a simplified method of direct spread spectrum modulation which is not as sensitive as conventional systems to synchronization, and which does not require the spreading code in advance. | {
"pile_set_name": "USPTO Backgrounds"
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Over many years, this inventor pursued various implementations of toroidal devices beginning with systems that would have an electronic output (missile nose cone signal transmitters), to very high reduction positioning devices (radar and telescopes), and, lately, to compact, high-torque power XYZ transmissions that can be used in, for example, trucks, automobiles, and marine vessels. Exemplary embodiments of toroidal drive transmissions are disclosed in U.S. Reissue Patent 26,476, issued on Oct. 8, 1968; U.S. Pat. No. 4,297,919, issued on Nov. 3, 1981; U.S. Pat. No. 5,784,923, issued on Jul. 28, 1998; and U.S. Pat. No. 5,863,273, issued on Jan. 26, 1999. The entire teachings of the above documents are incorporated herein by reference.
A transmission of the type described in the above patents is depicted in FIG. 1. The load-sharing elements in this type of transmission comprise rotor units 10, each of which includes a hub 12, a ring 14 rotatably mounted coaxially to the hub, and a plurality of fingers 16 or rotor unit arms extending radially outward from the ring. The fingers are terminated by drive rollers 18. The rotors 10 are mounted via the hubs 12 to a large ring 20, which can be referred to as a yoke, centered on the common rotary axis of the transmission input and output shafts 22 and 24. The drive rollers 18 of radially extending inner fingers 16 of the rotor units 10 engage in the grooves of a worm 26 connected to the input shaft 22, and the ring 20 to which the rotor units 10 are mounted is connected by arms 28 to the output shaft 24.
The outer fingers 16 of the rotor units 10 engage in grooves or races 32 inscribed in the interior of a transmission housing 34. When the drive worm 26 is rotated by the input shaft 22, the various rotor units 10 are caused to rotate about their respective hubs 12. Since the rotors 10 also engage in the stator races 32, rotation of those rotors 10 causes the rotors to advance along the races which, in turn, causes the ring 20 to which the rotor units are attached to precess about the rotary axis of the transmission. Since the ring 20 is connected to the output shaft by arms 28, when the ring 20 rotates, so does the output shaft 24. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention relates generally to air purification systems and more particularly to systems for reducing particles in air.
2. Description of the Prior Art
When a fuel burns incompletely, pollutants such as particles and hydrocarbons are released into the atmosphere. The United States Environmental Protection Agency has passed regulations that limit the amount of pollutants that, for example, diesel trucks, power plants, engines, automobiles, and off-road vehicles can release into the atmosphere.
Currently, industries attempt to follow these regulations by adding scrubbers, catalytic converters and particle traps to their exhaust systems. However, these solutions increase the amount of back pressure exerted on the engine or combustion system, decreasing performance. In addition, the scrubbers and particle traps themselves become clogged and require periodic cleaning to minimize back pressure.
Radiation sources and heaters have been used in exhaust systems, for example, to periodically clean the particle traps or filter beds. Others solutions have included injecting fuel into the filter beds or exhaust streams as the exhaust enters the filter beds to combust the particles therein. However, the filter beds can be sensitive to high temperatures and the radiation sources and heaters must be turned off periodically.
Air purification systems currently use one of two methods to remove particles such as dust, biological toxins, and the like from the air in a room. One type of system uses an ionizer to provide a surface charge to the air-borne particles so that they adhere to a surface. However, ionizers emit ozone, a respiratory irritant, into the air. Another type of system uses a filter, such as a HEPA filter, to trap particles as the air flows through the filter. However, filters need to be replaced or cleaned periodically. Both methods require a fan to circulate the air, which requires electricity and can be loud. | {
"pile_set_name": "USPTO Backgrounds"
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A typical structure for mounting the top of a radiator to a front-end module carrier includes an insulator on an upper mounting bracket. Bracket panels protrude from both sides of the insulator and are bolted to the front-end module carrier. Because the upper mounting bracket and bracket panels are large, reinforcing ribs are usually provided.
However, it is difficult to design strong ribs because of the structural limitations. Further, it is difficult to bolt the bracket panels to the front-end module carrier without bolt guides.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. | {
"pile_set_name": "USPTO Backgrounds"
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(1) Field of the Invention
The present invention relates to a condenser in which a fluid is evaporated into vapor state on warming, meanwhile the same is condensed into liquid state on cooling, and, particularly, the condensation of distinctly superior performance in comparison with the conventional can be efficiently attained.
(2) Description of the Prior Art
Generally speaking, in an electric power plant in which a motive power is generated by heat exchange effected by the circulation of an actuating fluid in vapor state at high temperature, for instance, a heated steam, a chemical plant in which the refining of materials is effected and the like, a condenser of this kind is indispensably employed. However, in most of the heat transferring sections of the conventional condensers customarily used in these various kinds of plants, cylindrical pipes, whose circumferential surfaces are smooth or rough, or which are fitted with fins, are arranged horizontally or vertically in parallel. So that, as for the conventional condensers having heat transferring (heat exchanging) sections constructed as mentioned above, that is, they are fixedly provided with plural cylindrical pipes, it is extremely difficult that any significant improvement of condensation performance in comparison with the conventional is attained, for reasons as follows.
(1) In the above described situation where cylindrical pipes are horizontally arranged, meandering of an actuating fluid is adopted as the flowing mode thereof for attaining a suitable heat exchange between the actuating fluid in vapor state at high temperature and a coolant, so that the pressure loss is increased.
In addition, when the heat exchange is effected, a large amount of actuating fluid condensed in liquid state is deposited on lower halves of horizontally arranged cylindrical pipes through which the coolant is circulated, so that the heat conduction through those lower halves is lowered and hence can hardly contribute to the heat exchange. Consequently, the coefficient of heat transmission is extremely decreased.
(2) In the above described situation where cylindrical pipes are vertically arranged, as the actuating fluid is circulated upwards and downward along a surface on which those pipes are vertically arranged, thick films of actuating fluid condensed in liquid state are deposited on lower halves of those vertically arranged pipes, so that the performance of heat exchange for condensation is extremely deteriorated similarly as mentioned in the above item (1).
(3) As for the conventional condenser having the heat transferring (heat exchanging) section consisting of those pipes as described above, an extremely large number of manufacturing processes and a remarkably high cost are required for manufacturing and installing those heat transferring pipes, as well as for punching a punched partition plate on which those pipes are fitted in the heat exchanging section and for assembling the whole condenser.
(4) Many of heat transferring pipes are fixedly arranged and hence drops of actuating liquid formed on upper pipes drip on lower pipes so that the coefficient of heat transmission for condensation is abruptly lowered.
(5) In place of the above conventional multi-pipe type condenser, a plate type condenser has been recently provided. However, the conventional condenser of this recent type has a remarkably large coefficient of heat transmission in comparison with that of old type, meanwhile the pressure of coolant circulated therethrough is extremely increased.
Consequently, all of conventional condensers of the previously described kinds have various shortcomings respectively in spite of the types thereof and hence cannot efficiently attain the condensation of excellent performance. | {
"pile_set_name": "USPTO Backgrounds"
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The aim of an IDPS is to protect systems, computers, networks and network-connected devices from a variety of attacks threatening their confidentiality, integrity and availability. The Internet is an active ecosystem which evolves rapidly and constantly changes while new types of attacks emerge as the attackers become more sophisticated. In this context, an IDPS needs to be constantly updated in order to detect novel attacks.
IDPSs can be classified into two major categories namely anomaly detection and prevention systems and misuse and prevention detection systems. Anomaly detection and prevention systems are designed to identify deviations from a normal profile behavior in order to detect malicious actions. Even though this kind of system performs better in detecting previously unseen attacks, they suffer from a high False Positive rate rendering them unpractical solutions for protecting a sensitive infrastructure.
With a misuse IDPS, the detection process is based on known signatures or, in other words, detection rules aiming to distinguish legitimate traffic instances from the malicious ones.
Currently, state of the art approaches are able to generate rules for detecting popular classes of attacks, but significantly neglect the minority attack classes. Even if these types of attacks are less common, their impact on the targeted system is considered to be destructive. Attacks such as remote vulnerability exploitations or privilege escalation could lead to a system becoming compromised by an attacker or confidential information leaks, causing financial losses and harming the trustworthiness of the organization.
Analyzing network traffic flows in the context of IDPS is a challenging task mainly because of the nature of the network traffic data. Under realistic terms, a network is flooded with normal traffic flows and only a smaller fraction of the traffic may indicate malicious behavior. This leads to a highly unbalanced data set that is difficult to analyze. In addition, a network analysis process focuses on several features that have to be taken into consideration for distinguishing legitimate from malicious traffic. The aforementioned data properties combined with the numerous attack types introduce many challenges and affect the detection accuracy to a great extent. In short, in many settings, an IDPS is tasked to function with datasets that are characterized by: Being multi-classed (several types of attacks), Being multi-featured (several network traffic attributes), and Being highly un-balanced (many instances of normal network traffic, but very few instances of rare attacks).
Elhag, Salma, et al., “On the combination of genetic fuzzy systems and pairwise learning for improving detection rates on Intrusion Detection Systems,” Expert Systems with Applications 42.1 (2015): 193-202 describe complex classification techniques in the context of Fuzzy Rule Based Classification Systems. However, even using such complex classification techniques, which consume a great deal of computing power in comparison with embodiments of the present invention, only an 89.32% of average accuracy for the aforementioned attacks can be achieved. Additionally, this system cannot be exploited without de-fuzzing steps and considers only a subset of the search area.
Generally, state of the art approaches apply either sampling techniques on the datasets to come up with a subset with specific characteristics or remove redundant instances. In contrast, in an embodiment discussed below, the present invention advantageously uses all available data to infer attacks. | {
"pile_set_name": "USPTO Backgrounds"
} |
Bistable cholesteric liquid crystal displays were introduced in the early 1990's (see U.S. Pat. Nos. 5,437,811 and 5,453,863). Their zero-power image retention and sunlight readability led to their integration into numerous signs and battery-powered applications as reviewed in “Cholesteric Liquid Crystals for Flexible Displays” in Flexible Flat Panel Displays, Ed. G. Crawford, (John Wiley & Sons, 2005) J. W. Doane and A. Khan, Chapter 17. The technology is best suited for reflective color images. In the cholesteric display technology, multiple-color and full-color displays are preferably produced by stacking multiple cholesteric liquid crystal layers with each tuned to reflect a different wavelength, typically red, green, and blue (see U.S. Pat. No. 6,654,080). These three colors are additively mixed to achieve up to eight colors. Images with more colors are possible because the technology is amenable to grayscale. That is, the reflective brightness of each color can be electronically adjusted to any desired level between the display's maximum and minimum brightness. Each level of brightness is referred to as a gray level. The total number of colors depends upon the number of gray levels one can choose for each color layer. High resolution displays with as many as 4096 colors have been produced.
Commercial bistable cholesteric displays of the prior art display digital images and as such are made using of a matrix of pixels with each of the pixels having a small area. The resolution of the display depends upon the number of pixels and size of the display. Typical pixel sizes are substantially less than one square millimeter. These displays are typically manufactured on glass substrates. Recent progress has been made in commercializing displays built on flexible plastic substrates rather than glass. The new flexible displays are manufactured with a simple lamination process, and may be cut into interesting shapes after assembly. Of significance, these displays are very thin since thin plastic sheet material as thin as 12.5 microns can be used for the substrates making possible a display with the over all thickness less that 60 microns. Using cholesteric liquid crystals dispersed as emulsified droplets has made possible even thinner displays since all the materials of the display including the electrodes, substrates and cholesteric dispersion can be coated in thin layers.
Such developments suggest a display film that can be electronically switched from one color to another color that can be laminated to flat surfaces and even made to conform to curved surfaces in the form of a skin. Consumers frequently identify color as a necessity for several types of products, such as; clothing, accessories, hand held electronics such cell phones, personally worn electronics, medical indicators, and decorative items. The color on these items is defined on the product when purchased. Conventionally, it has not been possible to electronically change the color of these items after the initial purchase. Thin flexible displays for changing the color of articles, for example, an electrochromic layer or a cholesteric display skin for changing the color of cell phones, have been described in the patent literature but such devices have not been successfully implemented (Published Patent Application No. 2008/0074383 and U.S. Pat. No. 7,142,190). Such cholesteric display skins would suffer from a problem of gray scale discontinuity discussed below. Other products incorporate a color change indicator for either a sensorial signal to indicate the product is properly working or to indicate the user's attention is required. Several color indicator products exist such as battery testers (U.S. Pat. No. 7,188,996) and self expiring security badges (U.S. Pat. No. 6,752,430).
Cholesteric display films have not been suitable for electronic skin applications with tunable uniform colors because uniform gray levels have not been possible in areas around one square centimeter and larger. In areas of such size, the inventors have noticed that levels of gray become very non-uniform or blotchy in appearance. The reason for this is not completely understood but it is believed by the inventors to be a result of several possible causes such as: non-uniform cell gap thickness (varying distance between electrodes) and non-uniform conductivity of transparent electrodes. Such features have not been a problem in typical cholesteric matrix displays because the pixels are so very small that gray levels appear uniform on the scale of a pixel and image content makes the non-uniformity hard to detect across many pixels. Furthermore, nearly all commercial displays have been driven in a binary (on/off) mode not utilizing shades of gray. | {
"pile_set_name": "USPTO Backgrounds"
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1. Technology Field
The present invention generally relates to a memory erasing method, and more particularly, to a memory erasing method which can effectively execute an erase command on memory cells storing invalid data, and a memory controller and a memory storage apparatus using the same.
2. Description of Related Art
Along with the widespread of digital cameras, cell phones, and MP3 in recently years, the consumers' demand to storage media has increased drastically. Rewritable non-volatile memory is one of the most adaptable storage media to portable electronic products (for example, notebook computers) due to its many characteristics such as data non-volatility, low power consumption, small volume, non-mechanical structure, and high access speed. A solid state drive (SSD) is a storage apparatus which uses a flash memory as its storage medium. Thus, in recent years, the flash memory industry has become a major part of the electronic industry.
A sub memory module of a rewritable non-volatile memory module has a plurality of physical blocks, and each of the physical blocks has a plurality of physical pages. While writing data into a physical block, the data has to be written according to the sequence of the physical pages. Besides, a physical page already containing data should be erased before it is used for writing new data. In particular, each physical block is the smallest unit for erasing data, and each physical page is the smallest unit for programming (i.e., writing) data. In the management of a flash memory module, physical blocks are grouped into a data area and a spare area.
Physical blocks (also referred to as data physical blocks) in the data area are physical blocks already containing data and mapped to logical blocks. To be specific, a memory management circuit of a memory storage apparatus converts a logical access address to be accessed by a host system into a logical page of a logical block, writes the data to be written into a physical page of a specific physical block, and maps the logical page of the logical block to the physical page of the physical block. Namely, in the management of a rewritable non-volatile memory module, the physical blocks in the data area are considered used physical blocks (for example, already containing data written by a host system). For example, the memory management circuit records the mapping relationship between the logical blocks and the physical blocks in the data area in a logical block-physical block mapping table, wherein the logical pages in a logical block are sequentially mapped to the physical pages in the corresponding physical block.
Physical blocks (also referred to as spare physical blocks) in the spare area are used for substituting the physical blocks in the data area. To be specific, as described above, a physical block already containing data has to be erased before it can be used for writing new data. Thus, the physical blocks in the spare area are used for writing update data and substituting the physical blocks originally mapped to logical blocks.
Namely, in the management of a rewritable non-volatile memory module, the physical pages of the physical blocks in the data area and the spare area are alternatively mapped to the logical pages of the logical blocks for storing data written by a host system. In particular, during the operation of a memory storage apparatus, a writing operation may be aborted due to a power failure, and accordingly incomplete data may be stored in a physical block in the spare area. Thus, in an existing design, when the memory storage apparatus is powered on, a memory controller of the memory storage apparatus executes an erase command on the physical blocks in the spare area to ensure that the physical blocks in the spare area have all been erased, so as to avoid double programming.
However, along with the increase in the capacity of rewritable non-volatile memory module, it takes a very long time to execute the erase command on all the physical blocks in the spare area. Thus, after powering on a memory storage apparatus, a user has to wait for a very long time before the user can access the memory storage apparatus.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art. | {
"pile_set_name": "USPTO Backgrounds"
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As the technology develops, the semiconductor optoelectrical device has a great contribution in information transmission and energy conversion. For example, the semiconductor optoelectrical device can be applied to fiber-optic communication, optical storage and military system. Generally, the semiconductor optoelectrical device can be classified as three categories according to energy conversion type: converting electrical energy to light, such as light-emitting diode and laser diode; converting light to electrical energy, such as optical detector; converting the radiation energy of light to electrical energy, such as solar cell.
The growth substrate is very important to semiconductor optoelectrical devices. The semiconductor epitaxial layers of a semiconductor optoelectrical device are grown on the growth substrate, and the growth substrate also provides the supporting function to carry the semiconductor epitaxial layer. But, different semiconductor epitaxial layers need different growth substrates. In order to form the semiconductor epitaxial layer with high quality, it is important to choose a suitable growth substrate.
However, sometimes a good growth substrate is not a suitable carrier substrate for carrying the semiconductor epitaxial layer. Taking the light-emitting diode as an example, in the manufacturing processes of the red light diode, in order to form a better semiconductor epitaxial layer, GaAs substrate is generally selected as the growth substrate because the lattice constant of GaAs substrate is close to that of the semiconductor epitaxial layer though GaAs is opaque and has low heat dissipation, which is adverse to the ultra-bright light-emitting diode which requires good heat dissipation. Such kind of growth substrate with low heat dissipation ability would cause the light-emitting efficiency to decline dramatically.
In order to satisfy the different requirement of the growth substrate and the carrier substrate of semiconductor optoelectrical devices, the substrate transfer technology is developed. Namely, the semiconductor epitaxial layer is firstly formed on the growth substrate, and then the semiconductor epitaxial layer is bonded to the carrier substrate for further processing.
The known ultra-bright light-emitting diode is produced by wafer to wafer bonding. The bonding layer, which is composed of metal or non-metal material, is used to bond the semiconductor epitaxial layer and the heat-dissipation substrate together. However, the bonding layer of a single material would limit the flexibility of light-emitting diode design and the following wafer level package. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention generally relates to the field of the Internet. More particularly, the present invention relates to an improved system and method for identifying unique users accessing a web site.
2. Description of the Related Art
Internet commerce has become an increasingly popular form of commerce in the United States and throughout the world. In general, Internet-based commerce, often referred to as e-commerce, provides advantages to both suppliers and consumers. E-commerce provides vendors and service providers the ability to greatly increase their sales channel and distribution network with minimal cost. An Internet commerce site provides a convenient, effective and secure mechanism for potential buyers to browse, select and purchase goods or services in an easy and simple fashion.
An important consideration for owners and/or operators of web sites, which have been designed to handle Internet commerce, is the amount of web traffic flowing through the site. There are various metrics used to measure web traffic. Various web traffic analysis and tracking software is available to provide the owners and/or operators of web sites with detailed statistics. One commonly used metric, for example, is the number of web page accesses or web hits on a page of a web site. Many Internet sites display a counter to show the number of visitors since last counter reset. The number of web hits per page, measured over a given time period, may have a significant impact on the advertising revenues generated by the web site.
Web site logs and other software designed to measure and analyze web traffic, can provide a wealth of additional information regarding the user. For example, it may include detail such as the operating system of user's computer, web browser software used to access web site, hourly/daily/weekly frequency distribution of web hits, Internet Provider (IP) address of user, country of registration for the user's Internet Service Provider (ISP), etc.
Although it has been possible to get detailed statistics referenced above, such as the number of raw hits per web site, the data collected is often incorrect, inadequate and often misleading. Up to now, it has been difficult to accurately identify and count the number of clients accessing a web site. For example, raw hit data shows the number of times each file has been requested at a web site. It can give an idea of the number of clients visiting a web site. However, it may not be able to disclose further detail. Assuming 1,000 hits were recorded on a web site, the raw hit data may not be able to report whether the hits were generated by 10 visitors racking up 100 hits a piece, or by 200 visitors creating five hits each, or by one visitor creating 1000 hits.
One prior art method to identify unique, distinct or individual users is based on the use of cookies. Cookies are identifiers placed on a user's computer system by a web site that the user may have visited. Web sites may use cookies to identify and track a user's movement through the web site. The use of cookies is thus considered an intrusive technology. Many Internet users have expressed concerns over the privacy issues related to the use of cookies. In order to protect their privacy, many users disable the use of cookies (a standard option in many of the popular web browsers). Furthermore, some types of browser software and earlier versions of popular web browsers do not support the use of cookies. Also, users can refuse cookies on a per cookie basis, or modify their local cookie file at will. As a result, it has been difficult to accurately identify and count individual users using cookies.
Another prior art method to identify individual users is to require user registration before entering a web site. This method, in many respects, is similar to the use of cookies. However, unlike cookies (which have become virtually transparent and often unknown to the user) the user must knowingly enter self-identifying information to gain access to the web site. Many Internet users have expressed concerns over the privacy issues related to the need for user registration to enter a web site, in addition to the inconvenience of remembering yet another user ID and password. As a result, it has been difficult to accurately count individual and distinct users who have not participated in user registration.
Yet another prior art method used to identify individual users is tracking Internet Provider (IP) addressed to identify users. However, larger Internet Service Providers (ISP's) such as America On-line (AOL) use a proxy server. A proxy server sits between a client application, such as a web browser, and a real web server located on the Internet. The proxy server intercepts all requests to the real server to see if the proxy can fulfill the requests itself. If not, the proxy server forwards the request to the real web server. It may be possible for hundreds or perhaps thousands of clients, such as AOL clients, to be accessing a web site simultaneously but may still show the same IP address. As a result, it has been difficult to accurately identify and count individual users who may have been assigned to the same proxy server.
For these reasons, it would be desirable to provide an improved method and system for counting individual users accessing a web site. It would be desirable for the improved method and system to use non-intrusive technology, which would address the privacy concerns of users, yet at the same time be able to identify individual users accessing a web site. It would be desirable for the improved method and system to identify and count all unique users logged on to a proxy server and accessing the web site. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention generally relates to claims processing for policies relating to the life and health of a person, such as a life insurance policy, an annuity policy, a disability insurance policy, a supplementary health, a medicare supplementary benefits policy, a long-term care insurance policy, or any policy paying benefits or requiring a policy change on an event such as death, terminal illness, disability, a need for long-term care, health changes, medical/health services. In particular, embodiments relate to systems and methods of processing claims on multiple policies.
2. Description of the Related Art
To administer a claim for benefits provided by a life insurance policy, an annuity policy, a disability insurance policy, a supplementary health, a medicare supplementary benefits policy, a long-term care insurance policy, or any policy paying benefits similar to those above, a substantial amount of information must be collected and managed. Appropriate documentation must be identified and obtained, such as death certificates in the case of a claim of a life insurance benefit or medical provider verification of condition or service in the case of health/supplementary health. Handling claims relating to a given insured from the time that notice is received through final settlement and payment may involve collecting numerous pieces of documentation (police report, medical examination reports, etc.) to support payment on the claims, tracking numerous documents, generating and receiving numerous pieces of correspondence, and calculating and issue payment to multiple beneficiaries. Managing such information can be cumbersome and time consuming.
In some cases, an insured has more than one policy with a particular insurance company or its servicing affiliates. For example, an individual may have life insurance policies, a disability policy, and a long-term care policy with the same company, or processed by the same company on behalf of one or more other companies. Each policy may have different beneficiaries, premiums, and other terms and conditions.
Typically, an insurance carrier may look at claims for an insured on a policy-by-policy basis. The administration of claims for insureds with more than one policy can be fragmented and paper intensive. For example, if an insured has two life insurance claims with an carrier, the carrier may generate two sets of information requirements, one for each policy, issue two checks to beneficiaries, one for each policy, etc. Fulfilling such information requirements in such cases involves duplication in the claims administration process, providing additional opportunities for error, fraud and other management issues. Additional, more interaction may be required with outside persons and entities. The additional red tape may also place burdens on the insured or the insured family members. For example, a grieving spouse may receive a request for a death certificate under one policy, even if the spouse has already provided the request for another policy. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to a method for keyframe-based displaying of a video presentation whilst enabling a user to select among said keyframes, and through such selecting, displaying a substantially continuous video stream based on said presentation, and which method displays various such keyframes in parallel in a reduced and static video format. The use of keyframes as representative parts of a video presentation that is recorded for subsequent selective playback has been proposed elsewhere. A continuous video stream means that video remains xe2x80x9conxe2x80x9d, which may include animation, a series of stills, or an interactive sequence of images. The character may be various, such as film, news, or for example a shopping list. State of the art is represented by the article xe2x80x98Content-Based Video Indexing and Retrievalxe2x80x99 by S. W. Smoliar and H. J. Zhang, IEEE Multimedia, Summer 1994, pages 62-72.
By themselves, keyframes may be derived from the video material upon its reception at the user""s premises through some derivation algorithm, or keyframes may be labelled as such by the video provider, for example, in that each new video shot will start with a keyframe. The present invention recognizes that such keyframes should be utilized so as to give users a dynamic overview over the presentation, combined with useful facilities for enabling them to edit the material in a sensible manner.
Therefore, amongst other things it is an object of the present invention to provide a user with an immediate feel of the dynamic aspects, as well as of the static content of the video presentation, as combined in a single video screen. Now, according to one of its aspects, the invention is characterized in that said displaying is controlled as starting from a particular active keyframe which subsequently to the selecting acts as a dynamic video cursor frame within said format. In this embodiment, the cursor frame moves in real time, thereby enabling users to discern between keyframes, that may have similar scene configurations but different dynamisms.
Advantageously, the method allows for rendering an audio-accompanied video presentation, whilst said rendering is controlled as starting from audio associated to a particular active keyframe that subsequently to the selecting acts as a discrete video cursor frame within said format. In certain presentations, for proper editing the audio is more discriminative than the video, and so the audio could represent the ongoing stream, while the video keyframe would operate as a kind of xe2x80x9cheaderxe2x80x9d pertaining to the interval between the two successive keyframes in question. The video keyframe may remain static, while the active keyframe that works as discrete or discretely stepping cursor frame may be highlighted in an appropriate manner.
Advantageously, said dynamic video cursor frame freezes upon coinciding with the next displayed keyframe""s content. The freezed display content may pertain either to the start, or to the end of the interval that has just been displayed. Subsequently, the next keyframe may become the a dynamic video cursor frame. The taking over may be controllable and/or programmable: this allows a user to view what editing the presentation will produce. Also, upon going to a next interval, the display mode may be altered, such as from normal to fast or slow display. The invention may be used for fully digital video, or rather for video in which the various video frames have digital labels for easy addressing.
Advantageously, the keyframes are set in a hierarchical structure and/or various keyframes are allowed to be deleted from display for so joining intervals of said presentation before and behind the deleted keyframe. In this way, fine-grained as well as coarse-grained editing can be applied in quick alternation. Again, the hierarchical structure may be implemented through the provider, or rather through some clustering algorithm. For example, if keyframes will be found through some cross-correlation, a rather small discrepancy therein may signal a low level keyframe, whereas a high discrepancy may signal a high level keyframe. The first could occur between successive shots in essentially the same movie scene, whereas the second would pertain to a changeover between scenes, that also may change overall conditions such as lighting level dramatically. Another situation is when various different types of video matter follow each other, such as news, film, or a service shop list. All this may facilitate the operations of the end user.
The invention also relates to a device for keyframe-based displaying of a video presentation and having selection means for enabling a user to select among said keyframes, and based on such selecting rendering a substantially continuous sensory stream relating to said presentation, said display device being arranged for displaying various such keyframes in parallel in a reduced and static video format, characterized in that the device has control means for controlling said rendering as starting from a particular active keyframe which subsequently acts as a video cursor frame within said format. The providing of the recited facilities in the environment of a user terminal, such as an enhanced video recorder plus TV set combination is believed to greatly extend user-directed performance thereof. Further advantageous aspects of the invention are recited in dependent claims. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of Invention
This invention relates to beverage forming systems, such as coffee brewers that use a liquid to form a coffee beverage.
2. Related Art
Beverage forming systems that use a liquid, such as water, to form a beverage are well known. For example, U.S. Pat. No. 8,361,527 discloses a beverage forming system that uses a beverage cartridge containing a beverage material to make a beverage by introducing liquid into the cartridge. Liquid provided to the cartridge may be heated in a tank prior to delivery to the cartridge. | {
"pile_set_name": "USPTO Backgrounds"
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In an illumination device that illuminates a photographic subject during photography, it is known to provide a LED as a light emission element (refer to Patent Document #1). In Patent Document #1, an illumination device is disclosed that is provided with a xenon lamp and an LED, and a technique is described for turning on an LED that emits red colored light or an LED that emits blue colored light, in order to correct the color temperature of the flash light emitted by the xenon lamp. With regard to the amount of light emitted by the LED, it is shown in the drawings (FIGS. 4 through 6) to vary the length of its time period of illumination (light emission) according to the distance to the photographic subject and the amount of color temperature compensation.
Patent Document #1: Japanese Laid-Open Patent Publication H10-206942. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to a job execution system which executes a job directed by a user in accordance with the job execution mode of the group to which the user belongs as well as to a job execution apparatus and an image forming apparatus used for this system.
2. Description of Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
When a job is executed by the job execution apparatus such as an image forming apparatus and others, as before, the user must enter the job execution mode (operating conditions). However, it is troublesome to enter the execution mode every time a job is executed.
Therefore, in Japanese Unexamined Patent Publication No. Hei 10-254301, there proposed is the image forming apparatus which simplifies entry operation of the job execution mode by alterably storing multiple job execution modes in memory, and selecting one from the multiple job execution modes when the job is executed and allowing the apparatus to execute the job.
Now, recently, from the viewpoint of ensuring security and others, the use condition of the job execution apparatus is frequently controlled in accord with the group to which the user belongs. In addition, jobs are frequently executed in the job execution mode designated to each group.
Therefore, in the image forming apparatus stipulated in Japanese Unexamined Patent Publication No. Hei 10-254301, the job execution mode is stored in memory in accord with groups, and when the user who belongs to the group allows apparatus to execute the job in the job execution mode of the group, it is assumed that the entry operation of job execution mode can be simplified by selecting the mode stored.
However, in such case, for the user, the operation to select the job execution mode is necessary, and consequently, the user must remember the group to which the user belongs, and it is just the same troublesome. In the event that the affiliate group is changed, it is still more troublesome.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates to a multi-axis magnetic field sensing apparatus, commonly referred to as a magnetometer, and more particularly to a structure for use in such apparatus to mount magnetic sensing assemblies with their sensitive axes disposed in mutually orthogonal planes.
Multi-axis magnetometers employing separate magnetic flux sensors arranged with their sensitive axes in mutually orthogonal planes are well known for use in determining the sense and/or magnitude of randomly oriented magnetic field vectors and the like. The present invention is not concerned with the magnetic and electronic design of such instruments, but merely with the mechanical construction of a mounting structure for carrying the separate sensor assemblies with their respective axes disposed in the correct orthogonal relationship.
Magnetometers tend, by their nature, to be sensitive instruments requiring accurate mounting and alignment of the respective sensor assemblies for optimum results and it is further desirable that the assemblies be housed in a manner which minimizes the effects of undersirable outside influences, such as physical shock or changes in the orientation of a vehicle or the like on which the magnetometer is carried. | {
"pile_set_name": "USPTO Backgrounds"
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Due to continuous increases in memory and processing power, code generation has become popular method of increasing programmer productivity. In recent years, the popularity of code generators has increased. Code generators automatically generate source-level language code (e.g., C, C#, Visual Basic, Java . . . ). Use of automatically generated code may reduce development time and increase stability of code.
In particular, code generation has become popular in the context of object-relational mapping (ORM). Relational data storage systems (e.g., DB2, SQL Server, MySQL, . . . ) are utilized to store relational data and manage these of relationships. It is useful for software developed in source-level languages to access and manipulate the relational data stored in the relational data storage system. When the application software is managing the relational data, it should maintain the relationships inherent in the data. In addition, any changes or modifications to the relational data should be persisted back to the relational data storage system. | {
"pile_set_name": "USPTO Backgrounds"
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As shown in FIGS. 44 and 45, in a strip blade material 1 that is to be used as a punching blade, a blade edge part 3 is formed in an edge in one side in the width direction of a strip plate part 2. After being subjected to a necessary bending work or the like, the blade material 1 is used in an application such as formation of a notch line or a fold line in a piece of paper, a sheet, a plate, or the like. In the blade material 1, end parts in the longitudinal direction are straight-cut as shown in FIG. 44, or miter-cut as shown in FIG. 45. As seen from FIG. 44, the straight-cut work is a work of linearly cutting end parts of the blade material 1 over the blade edge part 3 and the strip plate part 2. As seen from FIG. 45, the miter-cut work is a work of cutting end parts of the blade edge part 3 in the end parts of the blade material 1 into a shape which is obliquely inclined with respect to end parts of the strip plate part 2, and is conducted, for example, in order to prevent a gap from being formed in the blade edge portion when blade materials are joined to each other. In FIG. 45, miter parts of the blade edge are indicated by a reference numeral 3a.
FIGS. 46 and 47 show the principle of a blade material cutting device which is conventionally known. The blade material cutting device comprises: a stationary blade part 5 having a slit 4 into which the blade material 1 is to be fed; and a movable blade part 6 which is laterally movable in front of the slit 4.
In the blade material cutting device, when the blade material 1 which has been fed as indicated by the arrow F in FIG. 47 is passed through the slit 4 of FIG. 46 and the feeding operation is stopped, for example, the movable blade part 6 is swung about a fulcrum f as indicated by the arrow a of FIG. 46. Then, a stationary edge 5a of the stationary blade part 5 and a movable edge 6a (see FIG. 48) of the movable blade part 6 cooperate with each other to cut the blade material 1. In this case, as shown in FIG. 47, the portion of the blade material 1 where the blade material 1 is overlaid on the stationary blade part 5, and by contrast the portion which is pressed by the movable blade part 6 is deformed in a side direction of the stationary edge 5a. After the cutting, the portion pressed by the movable blade part 6, therefore, the shape of the cut surface of the blade material 1 which is illustratively shown in FIG. 50A is bent as shown in FIG. 50B. By contrast, the portion supported by the stationary blade part 5, the shape of the cut surface of the blade material 1 shown in FIG. 50D is not deformed but is maintained to the original adequate shape as shown in FIG. 50C. When, in portion where the operation of feeding the long blade material 1 is stopped, a predetermined portion of the blade material 1 is cut by using the blade material cutting device shown in FIGS. 46 and 47, therefore, the cut surface shape of the front end 1a of the blade material 1 which is produced as a result of the cutting is not deformed but is maintained to the original adequate shape as shown in FIG. 51, but that of the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent. Also a portion W in the vicinity of the rear end 1b is similarly bent.
When the blade material 1 is to be cut, the strip plate part 2 and the blade edge part 3 of the blade material 1 must be overlaid on a support face 7 formed in the stationary blade part 5 as shown in FIG. 49. When the blade edge part 3 is not overlaid on the support face 7, particularly, the blade edge part 3 is bent.
When the straight-cut work shown in FIG. 44 or the miter-cut work shown in FIG. 45 is requested to be conducted, edges of the stationary blade part and the movable blade part must be formed into a shape which enables such a work.
FIGS. 52, 53, 55, and 56 show a blade material cutting device which can conduct the above-mentioned two kinds of cut works.
In the blade material cutting device, support faces 7a, 7b are formed respectively in right and left side faces of the stationary blade part 5, a stationary edge of the support face 7a on one side serves as a straight-cutting edge, and that of the support face 7b on the other side serves as a miter-cutting edge.
In the blade material cutting device, when the stationary edge for straight-cutting and a movable edge of a movable blade part 6 cooperate with each other to cut two or front and rear portions of the blade material 1 as shown in FIGS. 52 and 53, the front end 1a of the blade material 1 which is produced as a result of the cutting is not deformed but is maintained to the original adequate shape as shown in FIGS. 54A and 54B, but the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent as shown in FIGS. 54C and 54D. In the blade material cutting device, also when the stationary edge for miter-cutting and the movable edge of the movable blade part 6 cooperate with each other to cut two or front and rear portions of the blade material 1 as shown in FIGS. 55 and 56, the front end 1a of the blade material 1 which is produced as a result of the cutting is not deformed but is maintained to the original adequate shape as shown in FIGS. 57A and 57B, but the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent as shown in FIGS. 57C and 57D.
FIGS. 58 to 61 show another blade material cutting device which can conduct the above-mentioned two kinds of cut works.
In the blade material cutting device, the stationary blade part 5 is formed into a fork-like shape having a pair of right and left protrusions 8, 9. The above-mentioned support faces 7a, 7b are formed respectively in opposed left and right side faces of the pair of protrusions 8, 9, a stationary edge of the support face 7a on one side serves as a straight-cutting edge, and that of the support face 7b on the other side serves as a miter-cutting edge.
In the blade material cutting device, when the stationary edge for straight-cutting and a movable edge of the movable blade part 6 cooperate with each other to cut two or front and rear portions of the blade material 1 as shown in FIGS. 58 and 59, the front end 1a of the blade material 1 which is produced as a result of the cutting is not deformed but is maintained to the original adequate shape in the same manner as described with reference to FIGS. 57A and 57B, but the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent in the same manner as described with reference to FIGS. 57C and 57D. In the blade material cutting device, also when the stationary edge for miter-cutting and the movable edge of the movable blade part 6 cooperate with each other to cut two or front and rear portions of the blade material 1 as shown in FIGS. 60 and 61, the front end 1a of the blade material 1 which is produced as a result of the cutting is not deformed but is maintained to the original adequate shape, but the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent.
FIGS. 60 and 61 which have been described above show an example in which the blade material 1 is cut into a miter shape wherein an end part of the blade edge part 3 after the cutting is inclined in a direction along which the end part does not protrude from the strip plate part 2. In contrast, FIGS. 62 and 63 show an example in which the blade material 1 is cut into a miter shape wherein an end part of the blade edge part 3 after the cutting is inclined in a direction along which the end part protrudes from the strip plate part 2.
In the above-described blade material cutting devices, in the same manner as the conventional blade material cutting device which has been described with reference to FIGS. 46 and 47, there is a problem in that the front end 1a of the blade material 1 which is produced as a result of the cutting is maintained to the original adequate shape, but the rear end 1b of the blade material 1 which is produced as a result of the cutting is bent. | {
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1. Field of the Invention
This invention relates generally to an improved compact gas fired water heater for installation in recreational vehicles. Specifically this invention relates to a gas fired water heater of compact size with an improved combustion chamber that offers manufacturing, dimensional, cost and performance advantages over water heaters of this type currently available for such installations.
2. Description of the Related Art
While combustion chambers of various designs and configurations have been invented and used for furnace and other space heating applications, the methods employed over the years for combustion chambers for water heaters for the recreational vehicle market has been limited to direct vent type designs to meet rigid space limitations, test pressure requirements mandated by various regulatory codes, and design methods that will offer the most economical products to the RV manufacturer and the consumer. Consequently water heaters for recreational vehicles continue to be made with direct vent type combustion chambers employing either bent tubes that permit the inlet and outlet ends of the tube to both be positioned on the front of the water heater, or a larger diameter straight horizontal tube, closed at the rear, wherein gases enter the lower front half and exit the upper front half of the horizontally positioned tube.
With the bent tube type combustion chambers utilized in many RV water heater tanks today, hot gases are injected by a burner into an entrance of a tube in the lower portion of the water heater and exit the other end of the same tube in the upper portion of the water heater. Both ends, the entrance and exit, are positioned in front of the water heater, consequently the fronts of such water heaters must be large enough to accommodate the "U" shaped bend in the tube between the entrance and the exit. Due to the large radius required to made the "U" shaped bend without distorting the tube, the dimensions of such water heaters must be either wider or higher than a water heater employing the single straight tube type construction.
While water heaters utilizing a single horizontal tube type heat exchanger may have smaller width or height dimensions in front of the water heaters than water heaters made with bent tube type combustion chambers, they have other disadvantages. In this method of design, the products of combustion pass through the lower portion of the horizontal tube below an internal median divider that extends approximately four fifths of the way from the front to the back of the tube. The gases make a turn in the rear of the tube as they make contact with the rear closure plate, whereby they then move upward and exit through the top portion to the tube above the entrance. This construction while permitting compactness, has severe limitations in performance due to the slowing down of the movement of the hot gases resulting from the abrupt turn in back of the tube as well as the large internal diameter of the tube, generally 41/2" in the water heaters being offered today. A smaller tube diameter used in the same manner, while speeding up the flow of gases by having less internal area, would at the same time be ineffective since the total amount of heating surface making contact with the water would also be reduced accordingly, and in general, even the water heaters with the 41/2" diameter tubes have heating surface limitations below that of water heaters using bent tubes with separate inlets and outlets. In addition the total travel distance of the hot gases permitted with the straight horizontal tube type construction is also considerably less than the distance of travel within a combustion chamber that utilizes a separate inlet and outlet, and this further restricts the efficiency of such water heaters.
In a more recent invention, a combustion chamber is employed for compact water heaters that does not utilize a tube of any kind. This combustion chamber, similar to those used in furnaces in earlier inventions, utilizes two shell shaped halves welded together to form an internal flow pattern within a tank. While meeting the pressure requirements mandated for water heaters, this type of construction has several disadvantages inhibiting its use. Due to the large perimeters of the two halves utilized in its construction, a considerable amount of increased welding is required to weld the two halves together. In a typical water tank for a water heater of this type, the total amount of welding required for the tank is increased by approximately 20 to 25 percent. In the case of a glass lined tank, the increase in the area of the welded surfaces inside the tank, requires that additional cathode protection in the form of a larger anode be provided, further increasing the cost of the water heater to the consumer. Further, to insert the front of this type of combustion chamber into the front head of the water heater tank prior to welding, a large hole consisting of two circular holes joined together in the center with an additional narrow hole is required. This type of fabrication makes it difficult to perform automatic welding since the surfaces where the front head and combustion chamber come in contact are on different radiuses. Fit up problems between the head and combustion chamber complicate the problem even further, since minor variances in the size of the dimensions of the welds in the areas on the combustion chamber that must protrude through the tank head can result in either the combustion chamber not fitting through the pierced holes in the head, or a loose fit in the head which in turn makes it impossible to weld the combustion chamber successfully into the head with automatic welding.
A need therefore exists for a water heater with a combustion chamber design that will enable the water heater to meet the smallest front dimensional requirements for small compact water heaters for recreational vehicles, permit the best possible economies by reducing the total amount of welding required, permit fully automatic welding of the combustion chamber into the tank head, insure long tank life in the case of glass lined tanks without adding additional anode surface, and at the same time enable the water heater to obtain a higher recovery and better efficiency than water heaters of this type currently available to the consumers.
The present invention fulfills this need and provides further related advantages.
Various methods and designs have been used for combustion chambers over the years, most of which were used for furnace and other types of space heating applications. None of the referenced patents or prior art reveals or suggests a combustion chamber which is fabricated by inserting and welding two lengths of tubing into a coupler to make a smaller radius turn than could otherwise have been made by a bend, and then in turn mounting the combustion chamber horizontally into the tank by inserting the two opposite ends of the tubing through the front head of the tank and welding them into position. These prior art references are:
______________________________________ U.S. PAT. NO. INVENTOR ______________________________________ 4,771,762 Bridegum 3,405,690 Burrus et al. 3,062,233 Hammersley 3,056,400 Hammersley et al. 2,796,860 Pinkus et al. ______________________________________ | {
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This invention relates to an automatic processing machine to be used for processing of a light-sensitive color photographic material. More particularly, it pertains to an automatic processing machine for a light-sensitive color photographic material constituted substantially of processing tanks for color developing, bleach-fixing and stabilizing processing, having substantially no water washing tank.
In photographic processing, when the light-sensitive photographic material to be processed is for color, it is constituted to carry out automatically the steps of, for example, color developing, bleaching, fixing, water washing and stabilization, and sometimes bleaching and fixing may be conducted in the bleach-fixing processing in a both endowed with both functions. In photographic processing, there is the method of batch system processing, in which a processing solution in an amount necessary for development is housed in a processing tank such as color developing tank and developoment is effected while immersing a light-sensitive color photographic material in the processing solution in this tank. This is generally called as the tank development. According to this method, water washing is performed with pooled water, but it generally involves the drawback to impair stability of the color dye, and there is also the drawback that the color developing solution will be fatigued after 2 to 3 times of processing to be changed in color developing characteristics. To compensate for this drawback, there is the method in which processing is performed while supplementing the components consumed corresponding to the fatigue, but it is difficult to process stably a large amount of light-sensitive color photographic materials according to this batch processing. For this reason, it has generally been practiced to maintain always constantly the finished photographic performance by supplementing successively the components consumed while processing continuously the photographic materials, thereby maintaining the processing solution components at constant levels.
On the other hand, similarly as such photographic characteristics, durable storability of dyes in color photography is also an important characteristic, and it is presently very commonly accepted to maintain the durable storability by performing sufficient water washing processing. Accordingly, in commercial continuous color photographic processing, a large amount of water is required, and the amount of discharged water is also large, whereby the conditions of location affording supplying and discharging of large amounts of washing water have been required.
Whereas, in these days, the cost of civil tap water is increasing abruptly due to elevation in the development cost of water, and also the cost in discharging sewage water is also continuing to be increased. Such an elevation in cost of water may be due to merely an economical reason, but, on the other hand, in large cities with great populations, it is really occurring that supply cannot pace up with expanded demand. Thus, water resource, which has been said to be infinite, is now coming to the era of finiteness, and shortage of water leading to limited water supply is really occurring somewhere in Japan. In such a district, the situation is so serious as lacking for drinking water or laundering water, and it may be considered to be difficult to ensure washing water in photographic processing. And, in large cities, a water-saving type society is going to be created, in which people are not tolerant enough to afford use of a large quantity of water for washing in photographic processing.
Also, generally speaking, around these respective automatic processing machines, working spaces of desired vastness are necessary, in which works such as control of supplementing cocks, calibration of evaporation, exchange of processing solutions and dissolution of supplemental solutions are conducted. It is not desirable to have tap water piping for washing water or piping for discharged solution at the feet of these workers, because they are dangerous in working environment. Further, for installing newly or moving an automatic processing machine, piping construction is necessarily required, for which time and cost are necessary. For this reason, it would be desirable to have an automatic processing machine having a discharged solution recovery tank.
Further, as another tendency in recent years, the color automatic development processing is shifting from a large scale laboratory processing to a small size laboratory processing, and the so-called mini-laboratories with smaller amounts of processing are rapidly increasing. In such small size laboratories, miniaturization of an automatic developing machine is strongly desired. And, in such a small scale automatic processing machine, in addition to the demand for enabling omission of tap water piping for water washing, there is the demand for also omitting the piping for permitting the discharged processing solutions discharged from respective processing tanks to flow into the sewage waterway, and the volume of the discharged solution recovery tank is desired to be made as small as possible for this purpose.
And, the processing methods to perform stabilizing processing immediately after bleach-fixing or fixing processing without performing washing with water have been proposed by the present Applicant in Japanese Provisional Patent Publications Nos. 14834/1983, 34448/1983, 132146/1982 and 18631/1983, etc. in which counter-measures to overcome the above problems are clarified. However, as the result of the study by the present inventors, these methods were also found to involve various problems. For example, in the water washings of the prior art, since a large amount of water is employed, the preceding bath components brought in attached on the light-sensitive materials are considerably diluted therewith. Accordingly, the discharged solution could be discharged as such into rivers or sewage waterways. Whereas, in performing the above stabilizing processing, a large amount of the preceding bath components will become accumulated in the stabilizing processing solution, and therefore the discharged solution cannot be discharged as such into rivers or sewage waterways as prohibited by statutory regulations in pollution. For this reason, the discharged solutions must be recovered by specialists in disposal of discharged solutions with payment of recovery fees. Consequently, while no cost required for washing water may be necessary, an enormous amount of cost becomes necessary for disposal of said discharged solution.
Further, according to the study by the present inventors, the following problems have been found to be involved.
That is, during conveying light-sensitive materials by a conveying means such as a conveying belt or conveying rolls, if said conveying means is constituted of an endless belt, the stabilizing solution components filled in the stabilizing tank which is the final tank of the processing tanks is brought by the said endless belt into the color developing tank which is the foremost tank of the processing tanks to be accumulated therein, thereby changing the component ratio of said color developing solution, even accelerating deterioration (air oxidation) of the solution, ultimately affecting markedly bad influences on photographic performance. Thus, it has been found difficult to lower the amount of the solution supplemented to the color developing solution at a certain level or lower. This means that there is a limit in reduction of the amount of the discharged solution accompanied with supplement of the processing solution, thus indicating that the volume of the discharged solution recovery tank provided for the demand for prevention of pollution or the demand for silver recovery cannot be reduced and also that the tank recovery frequency cannot be reduced. Such a fact poses no problem in automatic processing machines of the prior art provided with a water washing processing tank with running water as the final tank of the processing tanks, and it is a problem inherent in the automatic processing machine which performs stabilizing processing as substituted for water washing as in the present invention. | {
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Complex systems are all around us, including such examples as highway and air traffic systems; telephone networks; financial and banking systems; systems for the manufacture, distribution and sale of retail goods; legal systems; computer systems of various types; information transmission networks; and many more. In large part, these systems are characterized by concurrency (i.e., a number of actions may be occurring at the same time) and by asynchronicity (i.e., there is no master clock controlling the timing of events; many events can occur independently of one another). The development, modification and management of such systems is a very expensive, time-consuming and difficult task. Because of these and other factors, considerable efforts have been devoted over recent years to developing ways to analyze, simulate and (in some cases) control such systems. For example, one would like to be able to know, analytically, whether a change proposed for the structure or control programs for the long-distance telephone network is safe, or if it will cause the system to become deadlocked under some set of circumstances; it is undesirable to simply wait to see if something disastrous is going to happen.
Computer-graphical methods are being used more and more frequently in the specification and design of complex systems. The resulting models provide a basis for validating the design concepts, because they can be understood both by the designer and by the user, and because they can be scrutinized to determine whether the user's requirements have been satisfied. The model can then be used as a guide to, or vehicle for, the implementation or control of the actual physical system. For example, a computer program implementing the model can be used to control the system operation. The system might, thus, be a telephone switching network and the program might operate the digital controller which, in turn, operates the switches. Or the system might be a subway traffic control system and the program might operate signal lights, dispatch scheduling, and so forth.
Executable models of complex systems (i.e., computer programs which model these systems) are now being introduced into practice. In general, they may be classified into two categories: (1) models based on an underlying mathematical framework and (2) models based on an ad hoc graphical representation tied to conventional programming languages. Both types of models can be executed and, in that sense, can be thought of as programs. Models of the first type, moreover, can be analyzed according to certain rules, to discover whether the system possesses certain behavioral properties. These properties include deadlock, safety, and some forms of invariance. Performance analysis is also possible in some cases.
Few, if any, techniques exist for effectively marrying the two categories of executable models. Thus, one does not readily obtain a model which is both graphically represented or constructed and which is also analyzable. One graphical approach which has been developed for modelling and simulating systems exhibiting concurrency and asynchronicity is that of Petri nets. One reason Petri net representations are used is that they are also somewhat analyzable. A good discussion of the history and general principles of Petri nets is contained in T. Murata, "Petri Nets: Properties, Analysis and Applications," Proceedings of the IEEE, Vol. 77, No. 4, April 1989 (New York) at 541-580, and T. Agerwala, "Putting Petri Nets to Work," Computer, Vol. 12, No. 12, Dec. 1979, at 85-94, both of which are hereby incorporated by reference. Though Petri nets have been very useful for modelling systems graphically and mathematically, and though theoretically they are useful for system analysis, as well, it has been found that there is a tradeoff between modeling generality and analysis capability. That is, the more general the model represented by the Petri net, the less amenable it is to analysis. Indeed, it has been said that the complexity problem is a major weakness of Petri nets; that is, Petri-net-based models become too large for analysis even for a modest size system. Moreover, Petri net models and models based on other such paradigms typically are not analyzable, though they are developed on sophisticated computer systems. Thus, they do not address details of behavior of the complex system which they model. In other words, they do not reveal properties of the modelled system, they only simulate it. Validation that the system behaves as desired occurs only by observing the actual operation of the system. Consequently, serious design flaws and performance limitations may not be discovered until the system is in use. Correction of these conditions can be very costly and time-consuming, to say the least. At least one hardware system has been proposed for implementing Petri net models. See U.S. Pat. No. 4,700,187, titled Programmable, Asynchronous Logic Cell and Array, issued Oct. 13, 1987 in the name of Frederick C. Furtek. Though this system permits simulation of Petri nets as, essentially, executable models, it still does not analyze system properties.
Accordingly, it is an object of the invention to provide an improved method for modelling complex systems.
It is another object to provide a method for generating executable models of complex systems.
Still another object of the invention is to provide a method for generating executable models of large complex systems from simpler models of parts of the system, i.e., subsystems.
Yet another object of the invention is to generate models of complex systems which are analyzable, to permit detection of predetermined system behaviors or properties.
A further object of the invention is to provide a method for graphically constructing executable models of systems, which are also analyzable. | {
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1. Field of the Invention
The present invention generally relates to a computer data storage device, and in particular to a device for retaining and supporting a computer data storage device in a computer enclosure.
2. The Prior Art
A personal computer comprises data storage devices for storage of data. Data storage devices of a personal computer include, but not limited to, hard disk drive, floppy disk drive and CD-ROM. These data storage devices comprise a rigid casing that is retained in a computer enclosure by means of bolts. Tightening/loosening bolts to mount/dismount the data storage device is a time-consuming and laborious job.
A data storage device comprising side rails fixed on opposite sides thereof for sliding along corresponding guiding channel formed in a computer enclosure simplifies mounting/dismounting the data storage device to/from the computer enclosure. An example is disclosed in Taiwan Patent Application No. 78201813. However, bolts are still required for fixing the side rails to the rigid casing of a data storage device. Similar examples are disclosed in Taiwan Patent No. 79209891 and U.S. Pat. No. 5,332,306 that further comprises manually operating retaining pawls for retaining the data storage device in the enclosure.
U.S. Pat. No. 5,599,080 discloses a computer data storage device comprising side rails having stamped projections for resiliently engaging with corresponding notches defined in the casing of the data storage device for attaching the side rails to the casing. The resilient engagement, however, is not sufficient to firmly and effectively maintain the rails on the casing.
It is thus desired to provide a computer enclosure that overcomes the problems discussed above.
Accordingly, an object of the present invention is to provide a device for efficiently and effectively retaining a data storage device in a computer enclosure.
Another object of the present invention is to provide a device for amounting a data storage device to a computer enclosure without using bolts.
A further object of the present invention is to provide a device capable of selectively mounting data storage devices of different sizes to a computer enclosure.
To achieve the above objects, a retaining device for supporting and retaining a computer data storage device in an enclosure in accordance with the present invention comprises an elongate body having a first face and an opposite face. Two sets of pins extend from the first face, each set comprising at least one pin interferentially engaging with a corresponding hole defined in the data storage device thereby attaching the retaining device thereto. The retaining device is slidably inserted into a channel defined in a corresponding side wall of the enclosure with the second face thereof confronting the side wall. A pair of spaced resilient limbs is formed on an end of the body. A leaf spring is arranged between the limbs for biasing projections formed on the limbs to engage with notches defined in the enclosure thereby securely retaining the data storage device in the enclosure. An auxiliary retaining member is selectively attached to the body comprising a base received in a recess defined in the second face and a pin extending from the base through a hole defined in the body for additionally engaging with a hole defined in the data storage device whereby the retaining device may be selectively attached to data storage devices of different sizes. | {
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It is known to pyrolyze organic materials to convert them to useful carbon and graphite articles, the practice dating back at least to the days of Edison. In more recent times, the development of carbon and graphite fibrous materials such as yarn, tow, cloth and felt has progressed at a rapid pace and numerous advances in their manufacture from such various organic fibrous precursors such as acrylic, cellulosic, polyvinyl alcohol, polyamide, polyimide, polyester, polybenzimidazole and the like have been made. In addition to the pyrolysis of fibrous materials, the pyrolysis of bulk resinous materials to produce a variety of glassy and amorphous carbons as well as crystalline carbons and graphites has also proceeded rapidly.
These disciplines overlap in the area of the so-called carbon-carbon and carbon-graphite composites. Carbon-carbon composites are, in general, carbon bodies reinforced with carbon fibers. The method used for the fabrication of these composites is by impregnation of low and high modulus carbon fibers in various forms such as yarn, tow, felt, or cloth in two and three dimensional weaves with a resin, pyrolytic carbon, or combinations of the two. Where a resin is used which may be a pitch or a polymer, the impregnated, cured, or uncured material is pyrolyzed by heating to temperatures sufficiently high to convert the binder to carbon. Where a pyrolytic carbon is used, a fibrous skeleton is impregnated with carbon by the thermal decomposition of a hydrocarbon gas such as methane. Modifications of these processes include reimpregnation of resins into carbonized bodies to increase density and properties, or impregnation of pyrolyzed fiber-carbonized resin composites with pyrolytic carbon to effect the same improvements. During pyrolysis, the matrix shrinks resulting in the development of stresses and/or cracks in the binder and a possible weakening of the bond between the fiber and the matrix. The impregnation of a carbon skeleton with pyrolytic carbon (produced by the thermal decomposition of a hydrocarbon gas) leads to a similar condition which is due to the anisotropic shrinkage of the matrix on cool down from process temperatures (1100.degree. C. to 1300.degree. C.). The above dimensional changes are responsible for the relatively low shear strengths of these materials. With increasing heat treatment temperature and high temperature (2000.degree. C. to 3000.degree. C.) heat treating cycles the dimensional changes in the binder or matrix phase increase leading to further reduction in the shear strength of the material.
The use of nondirectional fiber geometries such as in felted or 3-D weave patterns tends to obscure the above condition to some extent since the purpose of such fiber geometries is to reinforce the material in all directions. However, this scheme does not eliminate the basic problem of dimensional changes in the binder during processing.
A substantial advance could be made in the art of carbon-carbon composites if the problem of differential fiber-matrix dimensional changes could be eliminated. One approach that has been tried with limited success is to employ precursor fibers or partially carbonized fibers in a resin matrix instead of fully carbonized fibers in an attempt to match the shrinkage of the fibers to the matrix during pyrolysis.
This invention takes a markedly different approach to solving problems of fiber-matrix interactions, namely the elimination of the matrix entirely, and relies instead upon the plasticity of suitable precursor fibers to effect fiber bonding by a compression molding step prior to pyrolysis. In this way the strength and stiffness of carbon fibers can be exploited to produce articles having properties tailored to specific end uses, without introducing weaknesses associated with fiber-matrix interaction. | {
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A truck box is a container that is mounted in the bed of a truck, typically a pick-up truck. Ordinarily, the truck box is mounted directly behind the cab of the truck and spans the distance between the side walls of the truck bed. Items like tools, fasteners, and the like can be stored in the truck box rather than simply laying loose in the truck bed.
A typical truck box has a rectangular receptacle and a lid that opens to permit access to the interior of the truck box. Many truck boxes have lateral portions, termed “tray pockets,” that overlie the walls of the truck bed to provide additional storage space. In some instances a biasing device, such as a spring or gas cylinder, is mounted within the interior of one or both tray pockets to facilitate opening of the lid.
As the lid of a truck box should remain closed while driving or when the truck is not in use, it is often desirable that the truck box include a locking system that secures the lid in a closed position. One such locking system is included with truck boxes sold under the trade name JOBOX® by Delta Consolidated Industries, Inc. (Jonesboro, Ark.). This locking system has two palm buttons located in the side walls of the box ends. Actuation of either of the palm buttons releases an internal lock and, assisted by gas cylinders located in the tray pockets, raises the lid to an open position. The internal lock includes an engagement member that is pivotally attached to a base bracket and a pawl member that is coupled to the push buttons with a connecting rod. The engagement member includes a slot that receives a striker pin attached to the lid and is spring-biased to a position in which it releases the pin. The pawl member is spring-biased to engage either of two recesses in the engagement member to prevent it from moving to the release position. Thus, when the lid is closed, the pawl member maintains the engagement member in a position to engage the pin. Actuation of the palm button disengages the pawl member such that the engagement member is urged by its spring to pivot sufficiently to release the pin. The lid is urged by the gas cylinder to move to a raised position. Closing the lid causes re-engagement of the pawl member and engagement member to retain the lid in place. In many truck boxes, two internal locks are included, and they are coupled such that both release when either of the palm buttons is actuated.
Although this type of lock has proven to be popular, there are some shortcomings. For example, positioning of the pin and engagement member are important, and slight misalignment, either horizontally or vertically, can prevent the lid from closing securely. This can be problematic due to varying manufacturing tolerances (typically a truck box is the full width of a pick-up truck bed, so a slight mismatch of components can become greatly exaggerated over the full length of the truck box), or if the lid becomes slightly misshapen due to abuse, racking, or the like. Also, the use of springs for both the engagement member and the pawl member can reduce consistency of operation, particularly when two internal lock units are used and the pins engage the engagement member at slightly different times. | {
"pile_set_name": "USPTO Backgrounds"
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The Internet Engineering Task Force (“IETF”) Multi-protocol Label Switching (“MPLS”) working group has specified a set of standards that help provide quality of service (“QoS”) for applications running over the Internet Protocol (“IP”). The MPLS technology enables IP network operators to explicitly assign a specific path to origin-destination (“O-D”) pairs and to reserve resources along these paths. Because of this capability, MPLS allows network operators to exercise traffic engineering in the sense that if the amount of traffic between O-D pairs is known or can be estimated, then the paths between these O-D pairs (realized by the so called label switched paths (“LSP's”) and the bandwidth of the paths can be appropriately configured.
In practice, the amount of traffic that needs to be served by the network is often known only in terms of a minimum and maximum required bandwidth rather than in terms of a single bandwidth value. For instance, many (so called elastic) applications can adaptively adjust their required bandwidth to network conditions and can operate adequately if a minimum amount of bandwidth is provided. On the other hand, many applications' quality and performance does not increase after a certain level if the network provides more than a required “maximum” bandwidth.
In recent years there have been significant advances in researching and standardizing mechanisms that are capable of providing service differentiation in multi-service networks like the Internet. While there still seems to be a wide span of the methods which aim to provide QoS differentiation between contending flows, it is widely accepted that there is a need for traffic engineering mechanisms that control the access of the different traffic classes to network bandwidth resources. In particular, there is a growing interest in devising bandwidth sharing algorithms which can cope with a high bandwidth utilization and at the same time maintain some notion of fairness, such as the maximum-minimum fairness (“MMF”), proportional-rate fairness (PRF) and minimum-delay fairness.
Different aspects of the MMF policy have been discussed in various publications, mostly in Asynchronous Transfer Mode (“ATM”) Available Bit Rate (“ABR”) context, since the ATM Forum adopted the MMF criterion to allocate network bandwidth for ABR connections. However, these publications do not consider the issue of path optimization in the bounded elastic environment. Moreover, these publications do not consider the problems encompassing maximization of the minimal flow combined with optimization of the paths used by the demands. For instance, these publications study the speed of convergence of MMF allocation algorithms rather than focusing on path optimization.
In addition, MMF routing using widest-shortest, shortest-widest and shortest-distance algorithms have been studied. These algorithms do not, however, aim to explicitly maximize the carried traffic and consequently the path allocation is not formulated as an optimization task. Moreover, a number of fairness notions have been discussed and associated optimization tasks have been presented for the case of unbounded flows and fixed routes.
Although the MMF allocation has been widely accepted and studied in the literature, its appropriateness can be questioned because of the relatively low bandwidth utilization. As a result, the PRF allocation is a promising alternative to the MMF allocation. According to the PRF criterion, in the unconstrained case (i.e. when no minimum or maximum bandwidth requirement is associated with the flows), the rate allocations xd are fair, if they maximize Σd log xd under the capacity and bandwidth demand constraints. This objective may be interpreted as being to maximize the overall utility of rate allocations assuming each route has a logarithmic utility function. While the PRF allocation considers the path optimization problem, it fails to solve the problem and does not provide an efficient algorithm for path optimization when the flows are bounded.
Accordingly, there is a need for a method and apparatus for optimizing elastic flows in a multi-path network for a traffic demand. | {
"pile_set_name": "USPTO Backgrounds"
} |
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