A low frontal area, aerodynamic drag reducing and adjustable mounting device and bicycle saddle including, an integral saddle or interchangable saddle and fastening mechanism, and a horizontally running open rectangular shaped tube with an over sleeve, the rectangular tube and over sleeve having vertical and horizontal grooves respectively with common fasteners, that allow vertical, horizontal, and inclination adjustments and that are fastened to a bicycle frame.

1. Field of the Invention
This invention relates to a low frontal area, air channeling or aerodynamic base drag reducing bicycle saddle and adjustable mounting device. As disclosed, the invention relates particularly to a bicycle mount and saddle, but the application of its open adjustable mounting air channeling portion is not limited thereto.
2. Description of Prior Art
Overcoming aerodynamic drag has been an area of special concern and interest for bicycle frame and component manufacturers, especially where speed is considered to be of great importance, as in competitive cycling. However the problem of reducing aerodynamic drag cannot be adquately addressed apart from mechanical or structural concerns. One reason for this is that the rules that govern competitive cycling have traditionally disallowed any device added to a bicycle, or any part of the bicycle, that has, as its sole function, the reduction of forward air drag. This means that any improvement in the aerodynamic efficiency of a bicycle, as far as competitive cycling is concerned, must serve a structural or mechanical purpose for the bicycle as well, or that its aerodynamic benefits are consequent with its structural features.
In attempts to improve aerodynamic efficiency of bicycle frames, frame builders who use the traditional two triangle frame design that employs a main triangle composed of three brazed, welded, or glued tubes that connect the front fork, saddle, and peddles, with rear triangle affixed thereto, that holds the rear wheel, have made minor variations in the shape and arrangement of frame parts that either reduce frontal area, or smooth air flow around frame parts. The variation in the shape of frame parts includes, for example, reshaping of the vertical frame tubes to a tear drop or oval shape to smooth air flow and reduce base drag; and variations in arrangement include such things as the use of a mono seat stay in the rear triangle above the top of the rear wheel to reduce frontal area, instead of the traditional two stay configuration, sloping the top tube to accomodate the reduction of the height or the frontal area of the head tube, and bending the top tube and/or seat tube to smooth the air flow around these parts and their joints.
Bicycle component manufactures, likewise, have tried to reduce the aerodynamic drag of their components by changing the shape and reducing the frontal area of their parts. For example, the exposed area of a traditionally round seat post would be replaced with a tear drop shape, while the adjustable part that is received into the seat tube remained round.
A traditional bicycle saddle assembly will employ a saddle with two round rods, known as rails, running underneath the length of the saddle, and a seat post with a clamp that grips these rails, and which is received into the seat tube of the frame. The clamp on the seat post usually incorporates an adjustment mechanism for the inclination of the saddle relative to the horizontal plane of the ground, and the clamp can be loosened so the saddle can be moved forward or backward on the rails for adjustment forward and aft on the horizontal plane. Vertical adjustment is achieved by loosening a fastening bolt mechanism, usually permanently affixed to the seat tube of the frame, and then raising or lowering the seat post in the seat tube until the desired height is achieved, and this adjustment is retained by tightening the fastening bolt of the seat tube.
While this system provides adequate saddle adjustment, it was designed for a bicycle frame made of round tubes and requires close fitting parts, usually made of metal, that also serve the structural purpose of retaining lateral stiffness and bearing rider load. The said parts are also relatively expensive, and heavy, and because of their structural and mechanical requirements, they have a considerable frontal area. In addition, reshaping the exposed area of the seat tube to a tear drop or airfoil shape offers only a slight improvement in overall aerodynamics of the bicycle, and little or no improvement in the aerodynamics of the rider.
The aerodynamic drag, of a body as it moves through the air is comprised of both surface drag, which is the friction of the air as it moves over the surface, and base drag, which is the void or vacuum or wake of turbulent air behind the body. It is apparent, when this principle is applied to cycling, while the aformentioned aerodynamic improvements in components and frames maintain the structural and/or mechanical requirements, they offer only slight improvements in the aerodynamic efficiency of the bicycle, and none lend themselves to accomodate an improvement of the base drag of the body of the rider and frame simultaneously.


A multiport memory that allows simultaneous reading and/or writing to the same memory cells by shorting selected bit lines with other bit lines of cells whose row address from each port match.

The present invention is intended to prevent erroneous data writing of a multiport memory such as a so-called dual-port memory, etc. and enhance reliability of the data writing. The background of the advent of multiport memory will be explained first.
In a well known conventional semiconductor memory, an attempt to share the processing with each CPU by connecting a pair of CPUs to only one semiconductor memory requires connection between each CPU and only one semiconductor memory with a data bus line for sending or receiving information. However, if the data bus line is used in common from a plurality of CPUs, while one CPU sends or receives data from a semiconductor memory, the other CPU naturally cannot send or receive data from this semiconductor memory. Therefore, even when a plurality of CPUs are connected to an ordinary semiconductor memory, it has never been possible to simultaneously connect or allow access by a plurality of CPUs to the semiconductor memory for simultaneous data sending and receiving.
A multiport memory to which the present invention is applied enables such simultaneous data sending and receiving to a plurality of CPUs which cannot be realized with a conventional semiconductor memory. Namely, a multiport memory has a plurality of ports for only one memory cell array and connect CPUs to respective ports in order to enable the shared processing by each CPU. A multiport memory in which a total of two ports, one on the left side of memory cell array and one on the right side thereof, are provided is particularly called a dual-port memory which is used most frequently.


A holographic recording device for multiple recording a plurality of interference fringes of a reference light and intensity-modulated signal lights in a same area or in areas slightly shifted each other of a holographic recording medium is disclosed. The holographic recording device modulates the intensity of a signal light and modulates a phase of the signal light before or after the intensity modulation. A phase distribution of each signal light is changed every time when multiple recording is performed and after each phase modulation, the recording device determines if an assigned multiplicity has been achieved.

1. Field of the Invention
The present invention relates to a holographic recording device for recording interference fringes of 2 light beams on a holographic recording medium and a holographic recording method and, in particular, to a reduction of noise caused at a recording time of current interference fringes by preliminarily recorded interference fringes.
2. Background Art
A holographic data storage system for recording/reproducing a large amount of data by utilizing the holographic technology has been proposed recently. In such holographic data storage system, a multiple recording system is used in order to improve the recording density. In the holographic data storage system, a number of independent pages are recorded in one area. Typical examples of the multiple recording system are the angle-multiple recording system, the shift-multiple recording system and the phase-code multiple recording system and various other systems such as the speckle-multiple recording system are also known. When such multiple recording system is used, the recording capacity of the holographic data storage system becomes substantially large according to calculations. However, it is impossible in the existing circumstances to increase the capacity due to noise caused by previous interference fringe recording.
In recording data by using holographic technology, intensity of light on a holographic recording medium is large in the vicinity of an origin of the medium and light intensity on other areas is small as shown in FIG. 5. Incidentally, the high intensity component in the vicinity of the origin is called DC component. Such uneven distribution of light intensity is known as the DC component problem when a spatial light modulator (SLM), which performs only intensity-modulation is used. It is also known that, with such unevenness of light intensity distribution, various problems occur in a recording time and some countermeasures have been proposed in, for example, a publication "Holographic Data Storage; H. J. Coufal, D. Psaltis, G. T. Sincerbox ED; Springer; p. 259-269 Beam Conditioning Techniques for Holographic Recording Systems".
One of the countermeasures is a method using a random phase mask or a phase-diffusion plate. In the method using the random phase mask as a phase diffusion plate, light is diffused by an optical element, which has, for example, a pitch identical to a pixel pitch of a SLM and a random pattern having phase-difference of 0 and π, correspondingly to the pixels of the SLM. This optical element having a random pattern having phase-difference of 0 and π is called the phase-diffusion plate. When light is diffused by the phase-diffusion plate, the light distribution on the recording medium becomes uniform and the recording characteristics are substantially improved. However, it is known that, although the problem of the DC component is solved by using the phase-diffusion plate, noise of an image is increased as described in page 264 of the above mentioned publication.
One of causes of noise will be described. As shown in FIG. 6A and FIG. 6B, in the angle-multiple recording, interference fringes formed by signal lights and a reference light are recorded in a same recording area of a holographic recording medium 50 while changing an incident angle of the reference light with respect to the recording medium. In FIG. 6A, interference fringes of the signal light 101 and the reference light 201 is recorded in the holographic recording medium 50, which is referred to as a first multiple recording, and, in FIG. 6B, interference fringes of the signal light 102 and the reference light 202 is recorded in the holographic recording medium 50, which is referred to as a second multiple recording. When the multiple recording is performed, both a recording signal and various noises are recorded. One of the causes of various noises will be described.
In FIG. 7, a reference numeral 4-1 shows interference fringes of the signal light 101 and the reference light 201 and a reference numeral 4-2 shows interference fringes of the signal light 102 and the reference light 202. These two interference fringes are indispensable primarily. On the other hand, the reason why unnecessary interference fringes are produced will be described with reference to FIG. 8. After the interference fringes 4-1 are recorded first on the holographic recording medium 50, the interference fringes 4-2 are recorded on the holographic recording medium 50 by irradiating the holographic recording medium 50 with the signal light 102 and the reference light 202. In this case, when irradiation with the signal light 102 is performed, the signal light 102 is diffracted by the interference fringes 4-1 recorded firstly on the holographic recording medium 50. When the signal light 101 and the signal light 102 are identical completely, light identical to the reference light 201 may be generated by this diffraction. The light identical to the reference light 201 thus generated is diffracted again by the interference fringes 4-1 recorded firstly, resulting in a light identical to the signal light 101. The light identical to the signal light 101 thus generated interferes with the reference light 202. As a result, unnecessary interference fringes 5-1 are recorded together with the interference fringes 4-2. Incidentally, although it is assumed in this description that the signal light 101 and the signal light 102 are completely identical, the light identical to the reference light 201 is practically generated with intensity proportional to mutual correlation of these signal lights.

Holographic recording device and holographic recording method


The invention relates to a method and product for treating waste paper material in which the material is pulped to form a slush-like fibrous stock, an ink dispersing agent is added to disperse ink particles from the stock, and the dispersed ink particles are removed from the stock. The ink dispersing agent comprises a mixture of phosphated and carbonated sodium salts, which achieves effective ink dispersal at ambient temperatures and under neutral pH conditions. The ink dispersing agent can also be effectively used as a one-shot product without the addition of any other chemicals to the stock. It also detackifies and disperses stickies from the stock and improves white water clarity.

In the paper and board industry, the use of secondary fibres derived from recycling waste paper material is well-known, and the dispersal and separation of ink particles from waste paper material and its secondary fibres is a necessary step in the recycling of the material, particularly in the production of paper for newsprint, tissues, and fine paper.
In known re-cycling processes, the waste paper or "furnish" is usually placed in a hydropulper where it is mixed with water and the following chemicals:
(1) caustic soda or other de-inking chemical, PA1 (2) sodiummetasilicate a buffering agent, and PA1 (3) hydrogen peroxide or other bleaching agent.
In the hydropulper, the "furnish" is disintegrated into a fibrous pulp, which is then de-inked and bleached by the added chemicals. From the hydropulper the fibrous pulp or slushed fibres, with a consistency of 15% (as in high consistency pulping) or 5-6% (as in mills not using high consistency pulping), is dumped into a series of "dump" or storage chests where the slushed fibres are diluted down to a consistency of around 1.5%.
The "stock" or diluted slush fibres then pass to the de-inking equipment, which either consists of flotation cells or washing screens or a combination of these, where the dispersed ink particles are removed from the slushed fibres.
In the method of utilising flotation cells, a "collector" soap is added to the "stock" prior to entering the de-inking cell to agglomerate the dispersed ink-particles which then float to the surface of the cell on air-bubbles which are sourced at the base of the flotation cell and which are then skimmed off.
In the washing method of de-inking, the dispersed ink particles are washed out of the system by passing the stock onto a rotary decker, a sidemill screen, a screw press, or similar equipment, using large volumes of water.
These known methods of de-inking require the addition of a number of different chemicals to achieve the de-inking process which is generally carried out at high temperatures, for example at least 122.degree. F. (50.degree. C.), and under strong alkaline conditions. Some chemicals are also only effective for one of the two different methods, i.e. flotation and washing methods, and cannot be used in the other method. Furthermore, caustic soda, which is most commonly used in relatively large amounts as a de-inking chemical, can attack the fibres and may not be regarded as being envirorunentally safe when emptied from the mill into external water sources.

Method and product for treating waste paper material


A method and system for securing freight during transport. The method and system secure the freight by using rotatable clamping mechanisms configure to apply axial pressure to the freight so as to prevent movement or shifting in transit. The rotatable clamping mechanisms are rotatable between an fully-opened position, a closed position such that the freight is secured, and a stowed position.

In prior art systems, bulky freight items, such as cylindrical rolls of coiled steel wire or sheets, are secured to railcars or other conventional transport vehicles by way of nylon tie-downs. Each roll is secured by a nylon strap running through the eye of the roll, and the ends of the strap are attached to the vehicle. At least one or two additional straps are placed over the top of the cylindrical roll, with the ends of the straps also attached to the vehicle. The use of nylon straps to secure the cylindrical rolls has several disadvantages. First, the straps often break in continual use, and in particular, due to the frictional deterioration incurred during transport as the extremely heavy rolls shift. Also, the nylon straps are subject to theft or loss. Because the straps are not permanently attached to the vehicles, they are easily removed and misplaced. Finally, the method of securing the rolls with the nylon tie-downs is extremely time-consuming, especially considering the large number of rolls being shipped daily.
When shipping alternative freight loads such as logs, pipes, and even pallets of goods, the freight tends to shift during transport. Shifting of the freight can cause damage to the goods and possibly loss of the freight as it can fall off the vehicle en route. While repetitive longitudinal forces acting upon the freight due to stopping and starting can cause the freight to shift, the forces from hunting, caused by chatter between the wheels and the rail, are the most dangerous to the freight.

Clamping system and method for securing freight


A reflecting film including: an Ag or Ag-base alloy thin film of an Ag-base alloy containing at least one element among Au, Pt, Pd, Bi, and rare-earth elements as a first layer; a film of an oxide or oxynitride of at least one element among Si, Al and Ti having a thickness between 5 and 50 nm as a second layer deposited on the first layer; and a film having a thickness between 10 and 100 nm formed by a plasma polymerization process as a third layer deposited on the second layer.

The present invention relates to a reflecting film excellent in cohesion resistance and sulfur resistance for lighting fixtures for the interior and exterior illumination of residential and office buildings or for headlamps for automobiles and trains.
Ag thin films or Ag-base alloy thin films have been used as reflecting films coating the inside surfaces of reflectors for lighting fixtures for the interior and exterior illumination of residential and office buildings or for headlamps for automobiles and trains. Ag thin films and Ag-base alloy thin films have high reflectance with visible light rays.
Ag is characterized by easy cohesion. Cohesion of Ag atoms reduces the reflectance of the reflecting film. The cohesion of Ag is caused by the adsorption of halogen ions and moisture contained in the atmosphere by the Ag and Ag-base alloy thin films. Therefore, Ag and Ag-base alloy thin films are coated with various resin thin films and coating films, respectively, to prevent the cohesion of Ag. However, the cohesion of Ag is caused often by halogen ions and moisture reaching the Ag and the Ag-base thin films through pinholes in the resin thin films and coating films. Cohesion of Ag forms innumerable white spots in the surfaces of Ag and Ag-base alloy thin films and causes color changes in Ag and Ag-base alloy thin films. Formation of white spots and color changes not only reduce reflectance but also spoils aesthetic appearance and deteriorate commercial value.
The reflecting film has a problem in addition to the problem of cohesion. The reflecting film is exposed to heat of high temperatures between 80 and 200° C. generated by a lamp when the lamp is lighted. Then, sulfur (S) contained in the atmosphere and diffused into the reflecting film reacts with the Ag of the reflecting film. Consequently, the surface of the reflecting film is sulfurated gradually and becomes dark and the reflectance of the reflecting film decreases.
Ag has been widely used as a material of electrical contacts and decorative films and the sulfur resistance of electrical contacts and decorative films has been improved by various methods including methods using alloys and those using multilayer films. For example, an Ag-base alloy disclosed in JP-A-55-85646 contains at least two elements among Pd, Au and Pt as additional element in a total content between 10 and 60 wt %. A multilayer film disclosed in JP-A-5-47251 has an Ag—Sn alloy base layer, and an Au or Au-base alloy thin film of a thickness between 10 and 200 nm deposited on the Ag—Sn alloy base layer. The Ag-base alloy and the multilayer film are excellent in sulfur resistance and are useful for forming electrical contacts and decorative films. However, the alloying elements contained in high alloying element contents and the Au thin film deposited on the surface of the Ag—Sn base layer reduces reflectance. Therefore, the Ag-base alloy is not suitable for forming the reflecting film and the multilayer film is unsuitable for use as a reflecting film.

Reflecting film excellent in cohesion resistance and sulfur resistance


A positioning information processing apparatus includes positioning information acquiring means for acquiring positioning information at predetermined standard time intervals; and positioning information transmitting means for transmitting outside the positioning information acquired by the positioning information acquiring means through a predetermined data communication path only if the positioning information is effective.

1. Field of the Invention
The present invention relates to a positioning information processing apparatus and a method of processing positioning information, which are capable of acquiring positioning information by the use of, for example, a global positioning system (GPS), and to a program executed by the positioning information processing apparatus. The present invention also relates to an information processing apparatus having a structure as the positioning information processing apparatus.
2. Description of the Related Art
Consumer devices having functions of measuring positions by the use of, for example, GPSs (devices supporting GPSs) are in wide spread use. In the present circumstances, vehicle navigation apparatuses, portable positioning apparatuses for climbing, mobile phones having GPS positioning functions, and so on are well known. For example, a cellular phone with a positional information function is disclosed in Japanese Unexamined Patent Application Publication No. 2004-233150.

Positioning information processing apparatus, information processing apparatus, method of processing positioning information, and program


A process for removing PCDD's and PCDF's from cellulose-containing fibers such as waste paper is provided. The process comprises contacting the fibers with supercritical or near supercritical carbon dioxide for a period of time sufficient to extract a substantial portion of the PCDD's and PCDF's without substantially damaging the fibers. Extraction efficiencies of greater than 95% have been achieved with the technique.

The present invention relates to the use of supercritical or near supercritical carbon dioxide to remove polychlorinated dibenzo-p-dioxins, (referred to hereinafter as "PCDD's" or simply "dioxins"), and polychlorinated dibenzofurans, (referred to hereinafter as "PCDF's") from secondary fibers.
As known in the art, secondary fibers comprise materials, usually cellulose-based, which have been used at least once in their intended primary use area but are, nevertheless, amenable to further processing and subsequent reuse. Waste paper, newsprint, ledger stock, packaging materials, cartons, boxes, computer printouts, telephone directories, corrugated boards, and the like represent suitable raw stock for conversion to secondary fibers. The pattern of reuse (i.e., use of the secondary fiber) may not always be similar to the use to which the primary (virgin) fiber was put.
Efficient management of solid wastes, of which cellulose-based materials constitute a significant part (e.g., waste paper, 40%; yard waste, 18%), has become an important societal theme. In recent years, efforts to recycle waste paper have intensified with the ever increasing concerns as to the rate of use of raw materials and the possible adverse environmental impact of common industrial processes. Novel screening systems and sophisticated flotation techniques have emerged which in large measure have successfully addressed the problem of deinking printed stock. New bleaching sequences which avoid the use of chlorine or chlorine compounds and rely solely upon hydrogen peroxide, dithionites, or formamidine sulfinic acid for attaining acceptable levels of brightness are also making their appearance.
One aspect of waste paper reuse, however, has remained a continuing concern. This area is the presence of small quantities of toxic compounds, in particular, PCDD's and PCDF's, in waste papers.
Bleached kraft fibers under a variety of guises (e.g., coated paper, ledger paper, etc.) are often present in substantial quantities in waste paper stock as purchased from commercial dealers. Kraft pulps, when bleached with sequences including an elemental chlorine stage, can contain small but detectable levels of PCDD's and PCDF's. The processing steps currently used to treat waste paper (e.g., pulping/screening/flotation/bleaching) are not effective in removing such compounds from stock containing chlorine-bleached fibers.
PCDD's and PCDF's are large groups of chloro-organic compounds which have become ubiquitous in industrial societies. The structures of these compounds are as follows, where in each case x+y =1-8: ##STR1##
Of the various possible isomers of these compounds, the following are reportedly the most
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) PA1 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PCDD) PA1 2,3,7,8-tetrachlorodibenzofuran (TCDF) PA1 1,2,3,7,8-pentachlorodibenzofuran (PCDF) PA1 2,3,4,7,8-pentachlorodibenzofuran (PCDF) PA1 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HCDD) PA1 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin (HCDD) PA1 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HCDD) PA1 1,2,3,6,7,8-hexachlorodibenzofuran (HCDF) PA1 1,2,3,7,8,9-hexachlorodibenzofuran (HCDF) PA1 1,2,3,4,7,8-hexachlorodibenzofuran (HCDF) PA1 2,3,4,6,7,8-hexachlorodibenzofuran (HCDF) PA1 2,3,7,8-tetrachlorodibenzo-p-dioxin PA1 1,2,3,7,8-pentachlorodibenzo-p-dioxin PA1 2,3,7,8-tetrachlorodibenzofuran PA1 1,2,3,7,8-pentachlorodibenzofuran PA1 2,3,4,7,8-pentachlorodibenzofuran PA1 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin PA1 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin PA1 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin PA1 1,2,3,6,7,8-hexachlorodibenzofuran PA1 1,2,3,7,8,9-hexachlorodibenzofuran PA1 1,2,3,4,7,8-hexachlorodibenzofuran PA1 2,3,4,6,7,8-hexachlorodibenzofuran.
Also reported to be highly toxic are:
See Rappe et al., "Analysis of Polychlorinated Dibenzofurans and Dioxins in Ecological Samples," in Chlorinated Dioxins and Dibenzofurans in the Total Environment II. Keith, L. H., Rappe, C. and Choudhary, G., eds., Butterworh Publishers, Boston Mass., 1985, pages 125-126.
In the recent past, the issue of health hazards associated with PCDD's and PCDF's has received much attention in the news media. PCDD's and PCDF's are known to cause a temporary form of a skin ailment known as "chlor-acne." Also, PCDD's and PCDF's (particularly 2,3,7,8-TCDD) have proved to be extremely toxic to certain animals in laboratory studies, in particular to guinea pigs (LD.sub.50 =0.6-4.0 micrograms/kilogram). See, for example, Ottoboni A., The Dose Makes the Poison, Vincente Books, Berkeley, Calif., 1984, and Dioxins, NTIS Report No. PB82-136847, Industrial Environmental Research Laboratory, Cincinnati, Ohio, November, 1980, Section 6.
Because of this reported high level of toxicity to a common laboratory test animal (i.e., the guinea pig), there is a general concern as to the long-term effects of PCDD's and PCDF's on human physiology. Accordingly, there is an important need to remove or substantially reduce the content of PCDD's and PCDF's from waste paper stock as part of the recycling process. It is an object of the present invention to respond to this need.
Supercritical fluids, including supercritical carbon dioxide, have been proposed for use in various industrial and pollution control processes. A review of this work can be found in Eckert et al., "Supercritical fluid processing" Environ. Sci. Technol., 1986, vol. 20, pp. 319-325. Among other things, these authors describe general applications of supercritical fluid technology to materials processing and pollution control. In particular, they discuss a study in which supercritical ethylene was used to remove trichlorophenol from soil as a model for the removal of dioxins and polychlorinated biphenyls (PCBs). No data are presented for dioxins. More particularly, the reference does not disclose or suggest removing dioxins from recycled paper using supercritical carbon dioxide.
Pang et al., "Supercritical Extraction of Aromatic Hydrocarbon Solids and Tar and Bitumens", Ind. Eng. Chem. Process. Des. Dev., 1985, vol. 24, pp. 1027-1032 discuss the use of various supercritical fluids, including carbon dioxide, to extract organic materials from tar sands. The reference mentions the possibility of using supercritical extraction to remove hazardous materials such as PCBs and dioxin from soils. Again, no data are presented for dioxins and no suggestion is made that supercritical carbon dioxide can be used to remove dioxins from secondary fibers. Also, the data presented for tar sands shows that carbon dioxide extraction produced the poorest yield.
Other studies involving the use of supercritical fluids including carbon dioxide to remove hazardous organic materials from environmental solids such as soil can be found in Groves et al. "State-of-the-art on the supercritical extraction of organics from hazardous wastes", CRC Critical Reviews in Environmental Control, 1985, vol. 15, pp. 237-274; Hawthorne et al., "Extraction and Recovery of Polycyclic Aromatic Hydrocarbons from Environmental Solids Using Supercritical Fluids", Anal. Chem., 1987, vol 59, pp. 1705-1708: Dooley et al., "Supercritical Fluid Extraction and Catalytic Oxidation of Toxic Organics from Soils", EPA Report No. 600/9-87/018F, pp. 383-397; and Brady et al. "Supercritical Extraction of Toxic Organics from Soils", Ind. Eng. Chem Res., 1987, vol. 26, pp. 261-268. None of these studies discloses or suggests the use of supercritical carbon dioxide to remove PCDD's and PCDF's from secondary fibers.
Along these same lines, U.S. Pat. Nos. 4,338,199 and 4,543,190 to Modell describe a process in which organic materials are oxidized in supercritical water. The '199 patent includes a general statement that its process can be used to remove toxic chemicals from the wastes generated by a variety of industries including forest product wastes and paper and pulp mill wastes. No specific mention is made of dioxins. The '190 patent describes the treatment of various chlorinated organics other than dioxins with supercritical water and states that conversion of these materials to chlorinated dibenzo-p-dioxins was not observed (see Example 6). The use of supercritical water to treat organic waste materials is also disclosed in PCT Patent Publication No. WO 81/00854, Modell et al., U.S. Pat. No. 4,113,446, Burleson, U.S. Pat. No. 4,564,458, and Titmas, U.S. Pat. No. 4,594,164.
A summary of experiments performed by Modar, Inc., using the Modell supercritical water process was published in Chemosphere--Chlorinated Dioxins and Related Compounds 1987, McNelis et al., editors, Pergamon Press, New York, 1989, Vol. 18, Nos. 1-6, page 50. As described therein, bench-scale tests were performed on soils and liquid wastes contaminated with chlorobenzenes and PCDD's. Supercritical water oxidation was found to remove 2,3,7,8-TCDD and chlorobenzenes from soil and to remove 2,3,7,8-TCDD, TCDD's and OCDD from liquid wastes.
Various uses of supercritical fluids in the processing of materials have been disclosed in the literature. For example, supercritical carbon dioxide has been used to remove tall oil and turpentine from coniferous woods in Fremont, U.S. Pat. No. 4,308,200, to extract lignin from the black liquor produced by the Kraft process for pulp production in Avedesian, U.S. Pat. No. 4,493,797, to treat refinery sludges in European Patent Publication No. 314,223, to regenerate absorbents used in waste water treatment systems in Modell, U.S. Pat. Nos. 4,061,566 and 4,147,624, to sterilize pharmaceuticals in Pilz et al., U.S. Pat. No. 4,263,253, to remove off-flavor materials from textured vegetable products in Sevenants, U.S. Pat. No. 4,675,198, to remove gamma-linolenic acid from fruit seeds in Traitler et al., U.S. Pat. No. 4,703,060, and to decaffeinate coffee in Katz, U.S. Pat. No. 4,472,442; Toro et al., U.S. Pat. No. 4,728,525 and Kaleda et al., U.S. Pat. No. 4,767,634. See also, Friedrich, U.S. Pat. No. 4,466,923: Lawson et al., U.S. Pat. No. 4,495,095; Myerson, U.S. Pat. No. 4,550,198; Panzner et al., U.S. Pat. 4,554,170: Japikse et al., U.S. Pat. No. 4,647,466; Ritter and Campbell, "The Effects of Supercritical Carbon Dioxide Extraction on Pine Wood Structure", Biotechnology and Bioengineering Symp., 1986, no. 17, pp. 179-182: Hatakeda et al., "Extraction of Sugi (Cryptomeria japonica D. Don) with supercritical carbon dioxide", Nipon Kagaku Kaishi, 1987, no. 5, pp. 931-933: Shishikura et al., "Concentration of Tocopherols from Soybean Sludge by Supercritical Fluid Extraction", J. Jpn. Oil Chem. Soc., 1988, vol. 37, pp. 8-12; and Li and Kiran "Interaction of Supercritical Fluids with Lignocellulosic Materials", Ind. Eng. Chem. Res., 1988, vol. 27, pp. 1301-1312.
Supercritical water or near supercritical water has been used to treat wood chips and black liquor from pulping in Modell, PCT Patent Publication No. WO 81/00855. See also Modell, M., "Gasification and Liquefaction of Forest Products in Supercritical Water", Fundam. Thermochem. Biomass Convers., 1985, 95-119; and West et al., "Pyrolysis of 1,3-butanediol as a model reaction for wood liquefaction in supercritical water", Can. J. Chem. Eng., 1987, vol. 65, pp. 645-650.
In addition to their use in waste treatment and materials processing, supercritical fluids have been used in connection with various analytic procedures. For example, Suprex Publication No. TN-022, Suprex Corporation, Pittsburgh, Pa., 1989, mentions the use of supercritical carbon dioxide as part of an analytical procedure for assaying dioxins, but no mention is made of using supercritical carbon dioxide for the reduction of dioxins in cellulosic substrates. Similarly, Hawthorne et al., "Directly coupled supercritical fluid extraction-gas chromatographic analysis of polycyclic aromatic hydrocarbons and polychlorinated biphenyls from environmental solids", J. Chromatogr., 1987, vol. 403, pp. 63-76, discuss the use of supercritical fluid extraction coupled to a gas chromatograph to analyze environmental solids, e.g., urban dust, for organic pollutants, specifically, polycyclic aromatic hydrocarbons. The extraction was performed using nitrous oxide as the supercritical fluid. Along similar lines, Schneiderman et al., "Determination of anthraquinone in paper and wood using supercritical fluid extraction and high-performance liquid chromatography with electrochemical detection", J. Chromatogr., 1987, vol. 409, pp. 343-353, describe the combination of supercritical fluid extraction using carbon dioxide, high-performance liquid chromatography, and electrochemical detection to analyze Kraft paper and pine plywood sawdust for anthraquinone.
Significantly, none of these references in any way discloses or suggests that the problem of removing PCDD's and PCDF's from secondary fibers can be solved by treating the fibers with supercritical carbon dioxide.
Some references exist in the literature regarding attempts to decompose or destroy dioxins in a state of solution in liquid media (e.g., hexane) or in substances such as silica gel or clay via photolytic techniques, e.g., UV radiation See Ottoboni, supra: Crosby, D. G., et al., Science, Vol. 173, Aug. 20, 1971, pages 173-174: Plimmer, J. R., Bull. Environm. Contam. Toxicol , Vol. 20, 1978, pages 87-92: Botre, Claudio, Adriana Memoil and Franco Alhaique, Environmental Science and Technol., Vol. 12, No. 3, March 1978, pages 335-336; Crosby, D. G., et. al., Environmental Health Perspectives, September 1973, pages 259-266 Dulin, David Howard Drossman, and Theodore Mill, Environ Sci. Technol Vol. 20, No. 1, 1986, pages 72-77: and Podoll R. Thomas, Helen M. Jaber, and Theodore Mill, Environ. Sci. Technol., Vol. 20, No. 5, 1986, pages 490-492. The process has been shown to work to an extent but appears to be highly dependent upon the presence of a hydrogen donor solvent, the type and level of impurities present, and the substrate. Furthermore, the photoproduct resulting from irradiation of 2,3,7,8-TCDD has been reported to be trichloro- and dichloro-benzo-p-dioxins, which are less toxic than 2,3,7,8-TCDD but, nevertheless, are undesirable.
As with the art relating to supercritical fluid technology, these references do not address the secondary fiber problem and, in particular, do not suggest that this problem can be solved by extracting PCDD's and PCDF's from such fibers using supercritical carbon dioxide.
In considering the problem of removing PCDD's and PCDF's from secondary fibers, it is important to note various characteristics of secondary fibers and of PCDD's and PCDF's which make the removal process particularly difficult. For example, secondary fibers have a relatively high surface area per gram. As known in the art, high surface area materials are capable of strongly binding organic compounds such as PCDD's and PCDF's. See Srinivasan et al., "Binding of OCDD, 2,3,7,8-TCDD and HCB to Clay-Based Sorbents," in Chlorinated Dioxins and Dibenzofurans in Perspective, Rappe, C., Choudhary, G., and Keith, L. H., eds., Lewis Publishers, Inc., Chelsea, Mich., 1986, page 532.
Moreover, in an air or water system, PCDD's and PCDF's will adhere to solid sorbents rather than remaining free in solution. Thus, partition coefficients in the range of 2.8-67.1.times.10.sup.3 have been reported for 2,3,7,8-TCDD for a variety of sorbents including hydroxy aluminum-clay and activated carbon. This compound also adheres quite well to glass in a water environment. See Srinivasan et al., supra at pages 531-537.
The combined effects of large surface areas and large partition coefficients makes the effective removal of PCDD's and PCDF's from secondary fibers difficult to achieve. It is to this challenge that the present invention is directed.

Method for removing polychlorinated dibenzodioxins and polychlorinated dibenzofurans from secondary fibers using supercritical CO.sub.2 extraction


A method and apparatus for effecting an accurate, clsoe tolerance guidance between relative movable male and female mold elements operable at high speed to mold thin wall articles free of the risk of mold damage due to relatively small occurrences of mold misalignment.

The relative motion of such molds (fixed cavity and movable core, fixed core and movable cavity or movable core and movable cavity) occurs along an axis common to both the core and the cavity.
Since, the wall thickness of the articles molded and thus the clearance between core and cavity, in the molding position, ranges from 0.010 to 0.020 inches, it is necessary to maintain accurate alignment of the core and cavity along the common axis to avoid mold damage caused by improper contact between core and cavity during the molding cycle.
A prior art device, over which the present invention is an improvement, is disclosed and described in U.S. Pat. No. 4,556,377, entitled Self-Centering Arrangement for Coacting Forming Tools, issued Dec. 3, 1985 to Paul P. Brown.
The '377 patent discloses an externally tapered mold cavity 15 cooperating with a ring 25 surrounding core 20 having a mating taper as at A to guide the core into the cavity to maintain alignment.
The '377 patent is incorporated into the file of this application.
While the device of the '377 patent is operative, it has not proved satisfactory in situations where the product wall thickness is of the order of 0.010 to 0.020 inches.
In addition, there is no means in the '377 device for effecting a positive "stop" when damaging contact between the core and the mold is imminent.

Anti-collision method and apparatus for an injection mold


An electrode for a polymer electrolyte fuel cell, which is a porous gas diffusion electrode comprising a catalyst powder and an ion exchange resin, wherein a solvent-soluble fluorine-containing polymer having substantially no ion exchange groups exists at least at a part of the inner surface of pores of the electrode.

1. Field of the Invention
The present invention relates to a polymer electrolyte fuel cell, an electrode for it and a method for producing it.
2. Discussion of Background
Attention has been drawn to a hydrogen-oxygen fuel cell as a power generation system which gives no adverse effect to the global environment, since the reaction product is only water in principle. A very high output is expected at a low operation temperature of from room temperature to about 150xc2x0 C., which is being studied recently. In such a case, it is assumed to use, as a fuel, hydrogen gas obtained by reforming a hydrocarbon such as methane, methanol or gasoline and containing e.g. carbon dioxide.
On the other hand, polymer electrolyte fuel cells have a low operation temperature. Accordingly, exhaust heat can hardly be utilized, for example, as an auxiliary power, and it is utilized only for hot water at best. To offset such a drawback, it is necessary for the polymer electrolyte fuel cell to secure a high output density. Further, for practical application, it is required to secure performance of a high energy efficiency and a high output density even under an operation condition where the fuel and air utilization ratios are high.
As the electrolyte for the polymer electrolyte fuel cell, a perfluorocarbon sulfonic acid type cation exchange membrane, which is an ultrastrong acid, is mainly used, in view of the chemical stability and electric conductivity. When such an acid electrolyte is used, the following reaction occurs at an air electrode, whereby water will be formed.
1/2O2+2H++2exe2x88x92xe2x86x92H2O
Therefore, under such an operation condition as a low operation temperature, a high current density and a high gas utilization ratio, clogging (flooding) at the pores of the electrode body is likely to take place due to condensation of steam, at the air electrode where water is formed. Accordingly, in order to obtain a stable performance of the fuel cell for a long period of time, it is necessary to secure water repellency of the electrode so as to prevent such flooding. This is particularly important in the case of a polymer electrolyte fuel cell whereby a high output density at a low temperature is desired.
To impart water repellency to the electrode, it has been studied to incorporate a fluorine-containing material to the electrode. Specifically, for example, the following methods (1) to (3) have been proposed. (1) A method in which a catalyst carrier is subjected to a fluorination treatment (JP-A-7-192738). (2) A method in which a fluorine-containing polymer is incorporated in the electrode (JP-A-5-36418). (3) A method in which a fluorinated pitch is incorporated in the electrode (JP-A-7-211324).
Among these, a fluorination treatment such as the method (1) requires a special equipment or technique, and thus it is unsuitable as a means to directly reform the surface of the carrier of the catalyst.
A fluorine-containing polymer which is insoluble in a solvent is used for the method (2). Specific examples include a tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter referred to as FEP), a tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (hereinafter referred to as PFA) and a polytetrafluoroethylene (hereinafter referred to as PTFE). In the present specification, a A-B copolymer means a copolymer having polymer units based on A and polymer units based on B.
To incorporate such a fluorine-containing polymer in the electrode as a water repellent, it is used in the form of a powder or a dispersion of the powder. The method of forming an electrode layer containing the fluorine-containing polymer, may, for example, be a method in which the dispersion of the fluorine-containing polymer is permitted to penetrate into pores of the electrode after the electrode layer is formed (2-1), or a method in which a powder or a dispersion of the fluorine-containing polymer is mixed with the rest of material which forms the electrode and then the electrode layer is formed (2-2).
The pore size of the gas diffusion electrode for a fuel cell depends on the method of producing the electrode. However, in general, the pore size distributes from about 0.01 to about several hundreds xcexcm. If the water repellency in pores is inadequate, clogging is likely to start from pores having a small pore size due to capillary phenomenon, in general. Accordingly, it is considered that if water repellency is imparted to the inside of pores having a pore size of at least 0.05 xcexcm, clogging of pores due to condensed water decreases, a quick electrode reaction can be made possible, and fuel cell properties will improve.
However, the primary particle size of the solvent-insoluble fluorine-containing polymer is about 0.1 xcexcm at smallest. Further, in the case where it is supplied in the form of a powder, it is usually granulated, and thus the average particle size is from about several xcexcm to about 500 xcexcm. Accordingly, it was difficult to let the solvent-insoluble fluorine-containing polymer penetrate to the inside of pores having a pore size of about 0.05 xcexcm, by means of impregnation, spray or filtration, after the electrode layer is formed. Namely, it was difficult to adopt the method (2-1), and the electrode layer was formed by the method (2-2).
On the other hand, in the method (2-2), a catalyst, a catalyst carrier and a conductive agent powder are mixed with the solvent-insoluble fluorine-containing polymer to prepare an electrode. Generally, carbon black is used for the catalyst carrier or the conductive agent, and the particle size is from 0.02 to 0.05 xcexcm. Namely, the particle size of the fluorine-containing polymer is larger than the particle size of carbon black. Accordingly, if the electrode is prepared by this method, the solvent-insoluble fluorine-containing polymer as a water repellent exists ununiformly in the electrode layer in the form of particles. Therefore, with this method, the inside of pores could not necessarily be made water repellent uniformly, although the pore size could be made large. Further, the solvent-insoluble fluorine-containing polymer is non-electroconductive. Accordingly, if the amount of the water repellent is increased in order to improve water repellency of the electrode, the resistance of the electrode may increase.
In the method (3), a polymerization reaction may take place in the process for producing the fluorinated pitch, and the fluorinated pitch is a polymer in a broad sense. In a case where the fluorinated pitch is insoluble in a solvent, there will be the same problems as in the method (2). Some fluorinate pitches are soluble in a fluorine-type solvent. In this case, the fluorinated pitch has a relatively low molecular weight at a level of from about 1,000 to about 3,000, and a six-membered plane structure, whereby the bonding force among molecules is weak, the film-forming property after drying is inadequate, and the fluorinated pitch is likely to fall off, so that durability is inadequate. Further, bonding between a carbon atom and a fluorine atom in the fluorinated pitch is likely to be cut in the presence of an alkali, and it is not sufficiently stable also in this respect.
It is an object of the present invention to provide an electrode for a polymer electrolyte fuel cell which is capable of keeping an adequate water repellency for a long period of time, and to provide a fuel cell having a stable performance for a long period of time, by using the electrode.
The present invention provides an electrode for a polymer electrolyte fuel cell, which is a porous gas diffusion electrode comprising a catalyst powder and an ion exchange resin, wherein a solvent-soluble fluorine-containing polymer having substantially no ion exchange groups exists at least at a part of the inner surface of pores of the electrode, and a polymer electrolyte fuel cell having the electrode.
The electrode for a polymer electrolyte fuel cell of the present invention contains a solvent-soluble fluorine-containing polymer having substantially no ion exchange groups, which imparts water repellency to the electrode. The fluorine-containing polymer is not particularly limited so long as there is a solvent capable of dissolving it. However, preferred is a fluorine-containing polymer which is hardly soluble in a solvent such as an alcohol or water which may be a reactant or reaction product in the electrode reaction of the fuel cell.
Further, the fluorine-containing polymer may be partially fluorinated or totally fluorinated. However, it is preferably in a solid state at a temperature within a range where the polymer electrolyte fuel cell is used, and specifically, it is preferably in a solid state at a temperature of from room temperature to 150xc2x0 C. Further, the fluorine-containing polymer of the present invention has substantially no ion exchange group. Specifically, the amount of the ion exchange group such as a sulfonic acid group or a carbonic acid group, is preferably at most 0.1 meq./g dry resin, particularly preferably at most 0.05 meq./g dry resin.
As the fluorine-containing polymer, a perfluorocarbon polymer having an alicyclic structure in the molecule is preferred. Such a polymer is hardly crystallizable due to twisting of the molecule attributable to the molecular structure, and it is soluble in a fluorinated solvent. Examples of the polymer include ones having cyclic structures of the following formulae, i.e. polymers having cyclic structures of the formulae 1 to 3 as polymer units. Among these, a fluorine-containing polymer having polymer units of any one of the following formulae 4 to 12, is preferred.
wherein 1 is an integer of from 0 to 5, m is an integer of from 0 to 4, n is an integer of from 0 to 1, 1+m+n is from 1 to 6, and R is F or CF3;
wherein each of o, p and q which are independent of one another, is an integer of from 0 to 5, and o+p+q is from 1 to 6;
wherein each of R1 and R2 which are independent of each other, is F or CF3.
Such a fluorine-containing polymer can be dissolved in a fluorinated solvent such as perfluorobenzene, trifluoroethane, AFLUDE (tradename of a fluorinated solvent manufactured by Asahi Glass Company Ltd.), or perfluoro(2-butyltetrahydrofuran), or in a solvent containing polyfluoroalkyl groups, and a solution having a concentration of from 0.01 to 50 wt % can be obtained.
As the fluorine-containing polymer of the present invention, a polymer made by partial fluorination of a non-acrylic resin may be preferably used, in addition to polymers of the formulae 1 to 3. Specifically, preferred is a copolymer having polymer units based on a fluoroolefin and polymer units based on at least one monomer selected from the group consisting of a vinyl ether, a vinyl ester, an allyl ether, an allyl ester, an isopropenyl ether, an isopropenyl ester, an acrylic ester and a methacrylic ester.
As the vinyl ether, an alkyl vinyl ether such as ethyl vinyl ether, butyl vinyl ether or cyclohexyl vinyl ether, a (fluoroalkyl vinyl)ether or a (perfluoroalkyl vinyl)ether made by partial or total fluorination of hydrogen atoms of the alkyl vinyl ether may, for example, be mentioned. As the vinyl ester, a fatty acid vinyl ester such as Beobar-10 (tradename of a commercial product manufactured by Shell Chemical) having branched alkyl groups, vinyl acetate, vinyl butyrate, vinyl pivalate or vinyl batatiate may, for example, be mentioned. The hydrogen atoms of the vinyl ester may be partially or totally substituted with fluorine.
As the allyl ether, an alkyl allyl ether such as ethyl allyl ether or cyclohexyl allyl ether may, for example, be mentioned. As the allyl ester, a fatty acid allyl ester such as allyl propionate or allyl acetate may, for example, be mentioned. As the isopropenyl ether, an alkylisopropenyl ether such as methylisopropenyl ether may, for example, be mentioned. The hydrogen atoms of the allyl ether may be partially or totally substituted with fluorine.
With regard to the copolymer having polymer units based on a fluoroolefin, the polymer units based on a fluoroolefin are contained preferably in an amount of from 30 to 70 mol %, particularly preferably from 40 to 60 mol %, since if the ratio of the polymer units based on a fluoroolefin is excessively large, the solubility in a solvent decreases.
The polymer obtained by partial fluorination of the non-acrylic polymer can be dissolved in at least one member selected from the group consisting of a ketone, an ester, a chloroethane and a benzene derivative, and the concentration of the solution can be made from 30 to 70 wt %.
The perfluorocarbon polymer having an alicyclic structure in the molecule and the polymer made by partial fluorination of a non-acrylic resin, which are mentioned above as the solvent-soluble fluorine-containing polymers, are hardly decomposable to a monomer, and thus they are not likely to undergo radical propagation, and excellent in acid resistance and alkali resistance.
The molecular weight of the fluorine-containing polymer of the present invention is preferably from about 2,000 to about 200,000, particularly preferably from about 5,000 to about 10,000. In the case where the weight concentration of the solution of the fluorine-containing polymer is same, in general, the larger the molecular weight of the polymer, the higher the viscosity of the solution having the polymer dissolved in the solvent. When using a polymer having a molecular weight within the rage as defined above, in the case where the electrode is impregnated in the solution of the fluorine-containing polymer to impart water repellency to the electrode, it is possible to keep the viscosity of the solution at a level where penetrability of the solution to the electrode is adequate, and at the same to obtain adequate adhesion to the surface of pores of the fluorine-containing polymer, and to maintain the water repellency of the electrode for a long period of time.
The electrode for a polymer electrolyte fuel cell comprises a catalyst powder, an ion exchange resin and a fluorine-containing polymer having substantially no ion exchange group and being soluble in a solvent. In addition, carbon to increase conductivity, a binder or a base material such as a fiber to maintain the shape, or a moisturizer such as SiO2 or TiO2 to absorb water, may be incorporated.
Various methods can be employed for producing the electrode for a polymer electrolyte fuel cell, by using the solution of the fluorine-containing polymer of the present invention. For example, it is possible to mix a solution having the fluorine-containing polymer dissolved, with a catalyst powder or an ion exchange resin which is another component to form the electrode, to form the electrode. It is also possible to spray or impregnate the solution to the electrode after the electrode is formed from such another component. Further, in a case where water repellency of the electrode has decreased after the fuel cell is used, it is possible to impart water repellency again to the electrode, by using the solution, i.e. by impregnation or spraying, as the case requires.
In the present invention, the solution having the fluorine-containing polymer dissolved can be used. Therefore, even if the particle size of another electrode-constituting material is small, or no matter how small the pore size of pores of the electrode, the fluorine-containing polymer exists on the inner surface of pores of the electrode after the solvent was removed by drying. The amount of the fluorine-containing polymer of the present invention existing in the electrode is preferably from 0.001 to 30 wt %, more preferably from 0.01 to 20 wt %.
As a method of producing the electrode for a polymer electrolyte fuel cell of the present invention, a known method such as spraying, coating or filtration of a mixed liquid comprising a catalyst powder of platinum-black or platinum supported on activated carbon, an ion exchange resin and, and if necessary, a pore forming agent, a thickener or a diluting solvent, is preferably employed. The water repellent may be preliminarily mixed in the mixed liquid, as mentioned above.
When producing a polymer electrolyte fuel cell using the electrode of the present invention, as a method of bonding the electrode and the ion exchange membrane as a solid polymer electrolyte, a method of directly forming the electrode on the ion exchange membrane, a method of forming the electrode in the shape of a layer on the substrate such as carbon paper, then bonding the electrode with the ion exchange membrane, or a method of forming the electrode on a plate and transferring the electrode to the ion exchange membrane, is preferably employed. When the electrode is formed separately from the ion exchange membrane, as the method of bonding the electrode to the ion exchange membrane, a hot press method or a bonding method (JP-A-7-220741, JP-A-7-254420) may, for example, be employed.
The ion exchange resin and the ion exchange membrane as a solid polymer electrolyte, contained in the electrode of the present invention, are preferably made of a fluorocarbon sulfonic acid type ion exchange resin or a fluorocarbon phosphonic acid type ion exchange resin. Particularly preferably, they are made of a perfluorocarbon sulfonic acid type ion exchange resin comprising a copolymer having polymer units based on CF2xe2x95x90CF2 and polymer units based on CF2xe2x95x90CFxe2x80x94(OCF2CFX)mxe2x80x94Opxe2x80x94(CF2)nxe2x80x94SO3H, wherein m is an integer of from 0 to 3, n is an integer of from 1 to 12, p is 0 or 1, and X is F or CF3, is preferred.
It is preferred to use PTFE, FEP, PFA or the like as the binder for the electrode of the present invention, and the amount is preferably from 0.01 to 30 wt % to the electrode. Such a binder has a function also as a water repellent. Further, it is preferred that the electrode contains a thickener of ethyl cellulose type, methyl cellulose type or cellosolve type.
Further, when forming the electrode, a diluting solvent may be used. As the diluting solvent, a fluoroalkane, a fluorotrialkylamine, a fluoroalkyltetrahydrofuran, a ketone, an ester, a chloroethane, a benzene derivative, an alcohol such as methanol, ethanol or isopropanol, a fluorocarbon, a hydrofluorocarbon, a hydrochlorofluorocarbon or water may, for example, be used.
The electrode of the present invention has a water repellency equal to or more than the ordinary electrode, and at the same time, the amount of a non-electroconductive resin can be made small, whereby the electrode can be made thin. Accordingly, it has an excellent gas diffusion property and low resistance, whereby it can be effectively used as both an air electrode and a hydrogen electrode. Further, it is possible to use the electrode of the present invention as an electrode at which water is formed by the reaction, and to use an electrode having no water repellency as the other electrode, to obtain a fuel cell having high reliability for a long period of time.
In the present invention, a solution of the solvent-soluble fluorine-containing polymer is used. Therefore, it is possible to uniformly coat the surface of the catalyst in the pores of the electrode by the fluorine-containing polymer, and to impart an adequate water repellency to the electrode by the fluorine-containing polymer, even if the amount of the fluorine-containing polymer is small. Further, in the case where the fluorine-containing polymer is incorporated to the electrode by e.g. impregnation or spraying, after the electrode is formed, it is easy to secure durability for the water repellent coating film obtained by drying, since the solution of the fluorine-containing polymer of the present invention has a film-forming property.
Further, in the production process to impart water repellency to the electrode, it is possible to impart water repellency to the electrode with high durability by the same operation as usual or a simpler operation than usual.
Now, specific embodiments of the present invention will be described with reference to working Examples (Examples 1, 4 and 6) and Comparative Examples (Examples 2, 3 and 5). However, the present invention is by no means restricted by such specific Examples.

Polymer electrolyte fuel cell, electrode for it and method for producing it


A toilet seat device includes a main part, a toilet seat, a load sensor, a controller, and a memory. The toilet seat includes a seating part where a user is seated, and a support leg part supporting a load applied to the seating part. The load sensor is provided in the support leg part and detects the load applied to the support leg part. The controller performs at least a body weight measurement of the user based on a detection result of the load sensor. The controller includes a register mode and a normal-use mode in the body weight measurement. The register mode includes determining an estimated value for estimating the total body weight of the user from the seated load. The normal-use mode includes estimating a load value relating to the total body weight of the user based on the estimated value.

Conventionally, a known toilet seat device can measure the body weight of a user by utilizing a toilet seat provided in an upper part of a sit-down flush toilet. Compared to a general body weight scale, the toilet seat device that can measure the body weight does not need storage space or the effort of obtaining the scale from the storage location and replacing it after each measurement is performed. Further, the sit-down flush toilet can perform daily body weight management continuously without conscious effort because the sit-down flush toilet is likely to be used daily by the user.
It is favorable to provide a load sensor at a support leg part of the toilet seat to be able to measure the body weight using a toilet seat device having a simple configuration (e.g., JP-A H6-8548 (Tokko)). To accurately measure the body weight of the user using the load sensor provided at the support leg part of the toilet seat, it is necessary for the total body weight of the user to be applied to the support leg part of the toilet seat. However, for the toilet seat device, for example, a foot of the user may undesirably touch the floor of the toilet room and cause the body weight of the user to be undesirably dispersed in the floor via the foot; therefore, the total body weight of the user is no longer applied to the toilet seat. Also, because the toilet seat is pivotally supported to be rotatable with respect to the main part, the body weight of the user may be dispersed through the rotation shaft part; and the total body weight of the user is no longer applied to the support leg part of the toilet seat.
Therefore, a toilet seat device is known in which the weight corresponding to the body weight applied to parts other than the toilet seat is predetermined by experiments, etc., before the body weight measurement; and the seated load that is measured by the toilet seat is increased by the weight corresponding to the body weight (e.g., JP-A H9-119859 (Kokai)).
However, the inventor of the application discovered that the body weight of the user dispersed in the floor of the toilet room and/or the rotation shaft part of the toilet seat changes greatly according to the physique, the sitting habits, etc., of the user; therefore, it is difficult to use the values determined by the experiments, etc., uniformly for all users.


A mechanism for providing an operating system history is disclosed. A method includes placing, by an operating system (OS) of a processing device, a pointer to context of a first application in a history context of plurality of applications in a direct interface array (DIR) of the OS upon indication of switching from an interface of a first application to the interface of a second application. The method also includes moving the pointer from the context of the first application to the context of the second application in the DIR in view of an indication of a closing of the interface of the second application. The second application is closed in a foreground of the OS and is executing in a background of the OS. The method further includes providing the interface of the second application in the foreground of the OS upon activation of a global back function.

When a user works on a computing device, the user may use multiple various applications. As such, the user may open these applications on the interface of the computing device. Often, the user switches between the applications or even closes the applications and later returns back to the closed applications.
Currently, a contextual history (e.g., an opened application with a position in that application) and a corresponding back button are implemented by the user for individual applications. Some examples of such implementations include Visual Studio™ and Eclipse™. Visual Studio™ is a software development environment (also known as an Integrated Development Environment or IDE) used primarily by software developers to build software products, websites and utilities including their interdependencies, configurations and version control information. Eclipse™ is an extension to the Visual Studio™ that provides global preferences, windows layout, and search and navigation history.
Both Visual Studio™ and Eclipse™ provide navigate forward and navigate backward options in the IDE environment, but are extended to a specific application. None of these mechanisms function on the level of an entire operating system (OS). This is because, at the OS level, applications are heterogeneous and re-launching the applications involves knowledge at the application level.


An interface cable connection is used for connecting between electronic appliances, particularly appliances associated with a computer. The connection includes a hood covering the connector. The connection is useful for preventing accidental electric shocks, filtering undesirable electromagnetic waves and facilitating connecting interface cables.

This invention relates to a connection for an interface cable connecting between electronic appliances, particularly appliances for computers. More particularly, this invention relates to a hood for covering a connector for use in a connection of the appliances.
In general, an electronic appliance, particularly a computer has a central processor arranged at a center to which are connected a memory device, an input unit, an output unit and the like to form one system.
For example, in the computer system above described, the respective devices are connected by so-called interface cables. In most cases, each of the interface cables has a so-called interface connector at its mid-point which detachably connects two parts of the interface cable.
FIGS. 1a and 1b exemplarily illustrate such a connector which is widely used.
The connector shown in FIGS. 1a and 1b is a coaxial two-core connector having a female connector A and a male connector B. In the connectors A and B, each of the main bodies 1 and 1' is made of metal and is formed of generally cylindrical configuration. The main body 1 or 1' is provided with an insulator 2 or 2' in which are embedded contacts 3 or 3' and a cylindrical annular conductor 4 or 4'.
A forward end of each of interface cable 5 and 5' is exposed and fixed to the connector A or B by means of a cable clamp 6 or 6' made of metal and provided in the main body 1 or 1'. Center conductors 8 of coaxial cables 7 in the interface cable 5 and 5' are electrically connected to the contacts 3 and 3' directly or through lead wires, and outer conductors 9 are electrically connected to the annular conductors 4 and 4' directly or through lead wires.
Moreover, the fixed portion of the interface cable 5 or 5' is covered by a conductive braid which covers the built-in coaxial cables 7 and is turned 180.degree. to cover a sheath of the interface cable. Since the fixed portion of the interface cable 5 or 5' is clamped to the conductive braid by means of the cable clamp 6 or 6', the conductive braid of the interface cable and the main body 1 or 1' of the connector are electrically connected to each other.
When the male connector B is moved in the direction shown by an arrow therefor in FIG. 1a, it is fitted in the female connector A so that a fitted condition of the connectors is obtained as shown in FIG. 1b. In this condition, the contacts 3 and 3' contact each other in contact recesses 2-1 of the insulator 2 of the female connector A, while the annular conductors 4 and 4' contact each other in an annular recess 2-2. A connecting nut or internal thread member 10' provided on the male connector B is threadedly engaged on screw-threads 10 formed on an outer circumference of the main body 1 of the female connector A so that the main bodies 1 and 1' of the female and male connectors A and B are electrically connected to each other.
With the development of electronic techniques, the number of electric and electronic appliances which rely upon electric power as their energy source have increased. With such an increase of appliances, various noise electromagnetic noise waves are emitted from these electric and electronic appliances to disturb their activity. For the purpose of eliminating such electromagnetic interferences, even with the usual interface connector of the prior art as shown in FIG. 1b, a filter such as an annular or cylindrical magnet, for example, a ferrite core 11 is fitted on the interface cable adjacent the connectors A and B as shown in FIG. 2. The filter is fixed thereat by a plastic mold 12, a thermally contractible tube or turns of plastic tape on the outer surface of the filter 11 so that undesirable electromagnetic waves are filtered to prevent them from affecting the electronic appliances.
The connectors of the prior art shown in FIGS. 1a and 1b and 2 include the metallic main bodies 1 and 1'. Therefore, when the connectors are connected or disconnected for the purpose of connecting, disconnecting or exchanging interface cables, there is often a risk of unpredictable and accidental electric shock or the like which may injure human bodies as the case may be, if high voltage is applied to the main bodies due to a thunderbolt, electric leakage or the like.
In case of a connector provided adjacent to a magnet capable of removing undesirable electromagnetic waves as shown in FIG. 2, special instruments and tools and difficult assembly operations are needed, such as injection molding of plastic coating, winding plastic tapes or heating for thermal shrinkage, in order to affix the magnet. Moreover, in cases where terminal treatment (forming of connections) of cables of predetermined lengths is effected off site in a factory, if lengths of cables are erroneously cut too short, they cannot be used and therefore are wasted.


Out of two display pixels connected to the same gate line G2, a display pixel (A) is connected to a source line S2, and a display pixel (B) is connected to a source line S3, which is adjacent to the source line S2 and forms a parasitic capacitance with a pixel electrode of the display pixel (A). A write signal for a display pixel (A) is obtained by correcting an input signal for the display pixel (A) in accordance with an input signal for a display pixel (B) or a write signal for the display pixel (B). With this arrangement, it is possible to reduce crosstalk between the two display pixels in a display device, such as a liquid crystal display device, that drives display pixels through a plurality of source lines and a plurality of gate lines.

Conventionally, many drawbacks of display devices in terms of color reproducibility have been pointed out. In particular, it has been pointed out that liquid crystal display devices have the following two drawbacks.
Many liquid crystal display devices allow light transmittance by using the birefringent characteristic of liquid crystal. However, liquid crystal of different pixels (pixels for R, G, and B) show different transmittance with respect to the same voltage. Therefore, even if the same color (e.g. white (R=G=B)) is displayed, the hue could be different, depending on gradation.
An effective measure to solve this problem is setting an independent γ curve with respect to each of R, G, and B, either in an analog or digital way. For example, Patent Publication 1 (Japanese Publication for Laid-Open Patent Application, Tokukai 2002-258813 (publication date: Sep. 11, 2002)) discloses such a technique for independently correcting each of R, G, and B.
In shutter-type liquid crystal display devices, light of each color leaks regardless of display gradation. Especially, if the display gradation decreases, color purity (color saturation) decreases due to the light leakage. Moreover, since luminance efficiency is regarded as an important factor for many liquid crystal display devices, spectrum characteristics of backlight and color filters must be broad even if contrast is sufficient. Under such circumstance, the color saturation decreases as the luminance decreases.
An effective technique for improving the color purity is emphasizing the color saturation by increasing color saturation of such color that has relatively high color saturation, and decreasing color saturation of such color that has relatively low color saturation. For example, Patent Publication 2 (Japanese Publication for Laid-Open Patent Application, Tokukai 2003-52050 (publication date: Feb. 21, 2003)) discloses such a technique for correcting the color saturation.
In addition, the problem of crosstalk, which is caused by the coupling of adjacent pixels through parasitic capacitance, has been pointed out as a problem unique to TFT-LCDs. If there is an insulating film between a transparent electrode and a source line, parasitic capacitance is formed there. Likewise, parasitic capacitance is formed between a gate line and the transparent electrode, and between a source line and a common electrode. Due to the influence of the parasitic capacitances and the capacitance of the liquid crystal itself, the potential of the display pixels could be different from desired voltages, when the gate is OFF. As a result, the display gradation could be different from a desired gradation. For example, Patent Publication 3 (Japanese Publication for Laid-Open Patent Application, Tokukaihei 5-203994 (publication date: Aug. 13, 1993)) discloses a technique for reducing the parasitic capacitances as a means of solving the problem of crosstalk. However, this technique is still insufficient to reduce the crosstalk.
Incidentally, although these prior arts are effective in order to adjust the color reproducibility of a panel as a whole or of each display pixel, these prior arts cannot respond to a situation where reproduced colors change in accordance with display patterns generated by a display device.
To a display pixel connected to a TFT, a desired voltage is applied at the moment the gate is high. On the other hand, when the gate is low, the display pixel is connected to many peripheral electric circuits through parasitic capacitances. Since many of these peripheral electric circuits are related to panel design, the driving voltage can be set in advance while considering the parasitic capacitance formed between the display pixel and the peripheral electric circuits. Thus, the crosstalk caused by the parasitic capacitances formed between the display pixel and the peripheral electric circuits can be compensated in advance. However, since the potentials of source lines for driving other display pixels cannot be determined in advance, the crosstalk caused due to the other source lines cannot be compensated in advance.
A liquid crystal display device shown in FIG. 15(a) is provided with source lines Si (i: integer) and gate lines Gj (j: integer) arranged to be orthogonal. At each intersection of a source line and a gate line, a display pixel 100 and a switching element 200 are provided. Among display pixels 100, each display pixel (A) is provided with parasitic capacitances Csda, Csdb, Cgd, and Ccs. A display pixel (B) is a display pixel adjacent to a display pixel (A) in the direction along which the gate lines are provided.
Details of the parasitic capacitances are as follows:                Parasitic capacitance Csda: parasitic capacitance formed between a display pixel (A) and the source line S2, which drives the display pixels (A);        Parasitic capacitance Csdb: parasitic capacitance formed between a display pixel (A) and the source line S3, which drives the display pixels (B);        Parasitic capacitance Cgd: parasitic capacitance formed between a display pixel (A) and the gate line G2, which drives the display pixel (A); and        Parasitic capacitance Ccs: parasitic capacitance formed between a common electrode line and a display pixel (A).
The capacitance of a display pixel (A) itself is Cp. The voltages applied to the gate lines change as shown in FIG. 15(b). While a display pixel (A) displays G, a display pixel (B) displays R or B. If the display gradation of the display pixel (A) is LA, and the display gradation of the display pixel (B) is LB, LA≠LB.
In this case, at the time the gate is high, if a drain voltage +V(A) is applied to the liquid crystal part of the display pixel (A), a drain voltage −V(B) is applied to the liquid crystal part of the display pixel (B). When the next gate line turns ON, −V(A) is applied to the source line for driving the display pixel (A), and +V(B) is applied to the source line for driving the display pixel (B).
In reality, however, a drain voltage is not applied directly to the display pixel (A). Instead, a drain voltage changed by the influence of the parasitic capacitances is applied to the display pixel (A). Specifically, an effective value Va of a voltage applied to the display pixel (A) is represented byVa=V(A)+(Csda×V(A)+Cgd×Vg+Csdb×V(B)+Ccs×Vc)/Cp where Vg is a voltage applied to the gate line, and Vc is a voltage applied to an opposed electrode.
Thus, the voltage applied to the display pixel (A) is different from the desired drain voltage (A).
The parasitic capacitances Csda, Cgd, and Ccs, which are formed in the vicinity of the display pixel (A), can be estimated at the design stage. Therefore, the drain voltage can be set appropriately by considering values of the parasitic capacitances. This means that the parasitic capacitances do not have much influence on the display gradation of the display pixel (A).
However, the foregoing formula for calculating the effective voltage Va includes the parasitic capacitance Csdb and the drain voltage V(B). This means that the voltage Va is influenced by the source line connected to the display pixel (B). Therefore, depending on the display gradation of the display pixel (B), color crosstalk is caused (that is, the gradation of the display pixel (A) changes).
For example, when V(A)=±2.59V and V(B)=±1.21V, the voltage supplied to the display pixel (A) is ±2.45V. Thus, it is found that color balance changes.
Even if the parasitic capacitances are reduced at the design stage as disclosed in Patent Publication 3, the amount of crosstalk is only reduced. The color crosstalk cannot be eliminated completely. Therefore, the potential actually applied to the display pixel changes in accordance with the display pattern of the display device as a whole. As a result, the display pixel cannot reproduce desired luminance.
In theory, it is possible to compensate the crosstalk by providing new members, such as shield electrodes or wires. However, if new members are provided to the display device, production cost of the display device increases.

Driving method for driving a display device including display pixels, each of which includes a switching element and a pixel electrode, display device, and medium


An image sensor includes a photoelectric conversion element including a first impurity region and a second impurity region, wherein the first impurity region contacts a first surface of a substrate, wherein the second impurity region has conductivity complementary to the first impurity region and is formed in the substrate and below the first impurity region; a pillar formed over the photoelectric conversion element; a transfer gate formed over the photoelectric conversion element to surround the pillar; and a channel layer formed between the transfer gate and the pillar and contacting the photoelectric conversion element, wherein the channel layer contacts the first impurity region and has the same conductivity as the second impurity region.

Exemplary embodiments of the present invention relate to semiconductor device manufacturing technology, and more particularly, to an image sensor including a vertical transfer gate.
An image sensor converts an optical image into an electrical signal. Recently, due to the development of the computer industry and the communication industry, a demand for an image sensor with improved performance has increased for various devices, such as digital cameras, camcorders, PCS (Personal Communication System), game machines, security cameras, medical micro-cameras, and robots.

Image sensor including vertical transfer gate


The invention relates to a method for generating electromagnetic radiation by a laser-produced plasma, wherein a target comprising a target material is provided, at least one pulse sequence is directed to said target, wherein the pulse sequence comprises four to nine conditioning laser pulses, wherein time intervals between subsequent conditioning laser pulses are 200 ns or less, and a main laser pulse is directed to said target along a first axis, such that a radiation-emitting plasma is formed from at least a part of said target material. The invention further relates to a device for generating electromagnetic radiation by means of a laser-produced plasma comprising a dispensing device and at least one laser source, wherein the device is configured such that at least one pulse sequence comprising four to nine conditioning laser pulses and a main laser pulse can be generated by the at least one laser source.

Devices for generating electromagnetic radiation by means of a laser-produced plasma, such as droplet-based laser-produced plasma (LPP) light sources are known from the prior art. These devices are capable of producing very bright point sources of light over an extremely broad range of wavelengths from X-ray to visible light depending upon the application. These high brightness point sources are used for example in the semiconductor industry as well as other manufacturing industries within scanning systems for detecting defects during the semiconductor manufacturing process. There is also a need for these sources in advanced high-resolution microscopes for studies of cell biology or additive manufacturing.
Droplet-based LPP light sources work by generating a high temperature plasma, particularly within a vacuum chamber. Therein, particularly, a droplet train of fuel or target material is generated within a droplet dispenser. A positioning system directs the droplet train through a laser focus. As the droplets align with the laser focus a high energy laser pulse irradiates the droplet, evaporating and ionizing a portion of the target material generating a high temperature plasma. This plasma acts as almost as a point source of radiation. The wavelength and brightness of the light source depends on the choice of fuel and the energy of the laser pulse. For the generation of extreme ultraviolet light (EUV) at 13.5 nm the target material is typically pure tin, lithium or xenon.
In these sources debris from the exploding droplet (often liquid metal) remains a challenge, since the liquid splashes coat optics and nearby instrumentation within the vacuum chamber, making long term source operation challenging.
The unevaporated portion of a droplet typically starts as a spherical shape that when subjected to a shock wave from the expanded plasma produces splash fragments of a predetermined size, wherein the fragment size distribution is highly dependent on droplet and laser parameters. The larger these splashes are, the more difficult it is to protect the source optics.
According to the prior art, the size of debris particles can be reduced by applying a single pre laser pulse to the target, thereby shaping the target prior to the main laser pulse (US 2017/0027047 A1, U.S. Pat. No. 8,164,076 B2, US 2006/0215712 A1, U.S. Pat. No. 9,820,368 B2, U.S. Pat. No. 7,928,416 B2, U.S. Pat. No. 7,239,686 B2).
However, these pre-pulsing methods known from the prior art have the disadvantage that only a limited repertoire of target shapes which are sub-optimal in terms of debris mitigation, conversion efficiency and/or stability of operation can be obtained.

Method and device for generating electromagnetic radiation by means of a laser-produced plasma


Low-complexity channel noise reduction method and apparatus for multi-carrier mode in wireless LANs are disclosed. The method selects an optimal frequency domain channel impulse response by using a known long training sequence and a highly protected signaling sequence of the multi-carrier mode frame structure to ensure the receiver to have a good operation threshold in different time-delay spread environments at the cost of a low complexity. Instead of detecting time domain channel responses, the method directly performs noise reduction to a noise-containing frequency domain channel by using preset Wiener filtering coefficients to obtain multiple frequency domain channel responses, among which there must be a relatively optimal frequency domain channel response. The relatively optimal frequency domain channel response can be selected by using the highly protected signaling sequence to calculate the signaling frequency domain channel.

In wireless communication systems, inevitable influence of terrains or obstacles on signals causes the occurrence of multipath distortion. As a time-varying channel impulse response is generally modeled as a time-domain discrete finite impulse response (FIR) filter denoted by
            h                    (                  τ          ;          t                )              =                  ∑        n                                                a            n                                          (            t            )                                            ⅇ                                    -              j                                                                                2                        π                                                                                f              c                                                                  τ                n                                                          (                t                )                                                                      δ                                (                          τ              -                                                τ                  n                                                                  (                  t                  )                                                      )                                ,complex multipath interference always exists in received wideband signals, which appears as frequency selective fading in the frequency domain. For this reason, single-carrier systems usually employ time domain equalization to eliminate the multipath influence, which results in a very high complexity of receivers.
The orthogonal frequency division multiplexing (OFDM) technology has been widely used in wireless wideband communication systems. One significant advantage of OFDM technology is its capability of dividing a carrier with a relatively wide bandwidth into multiple parallel subcarriers, each subcarrier having a bandwidth far less than the coherence bandwidth of a channel. Therefore, the channel frequency fading that each subcarrier signal undergoes is flat, which overcomes the adverse effect of channel frequency selective fading. If channel frequency response characteristics at different subcarriers can be obtained by channel estimation technology, a receiver will be capable of realizing coherent demodulation to correctly recover transmitted signals. In order to improve demodulation threshold of the receiver and the quality of received signals, noise reduction is generally performed to the estimated channel response.
Wiener filtering is a commonly used channel noise reduction technology in multi-carrier OFDM systems. In consideration of the implementation complexity, Wiener filtering methods are usually designed according to several groups of preset channel power delay characteristics, and the corresponding Wiener filtering coefficients are stored. The receiver selects appropriate Wiener filtering methods and coefficients according to the preset channel power delay characteristic in the practical transmission environment. The above concept is applied in the China mobile multimedia broadcasting (CMMB) system to perform noise reduction and interpolation by selecting the most appropriate group of Wiener filtering coefficients through analyzing the multipath delay spread in a transmission channel. However, this method is only suitable for CMMB systems or the like, which adopt a low quadrature amplitude modulated (QAM) transmission mode, as the low QAM transmission mode is not sensitive to weak paths in reception environment, and ignorance or loss of several weak paths will not effect the determination of constellation points. Moreover, as the energy of noise in the environment where a low QAM reception is located is relatively high, it is advantageous for the reception threshold if some weak paths together with the noise are inhibited. With the increase of transmission rate, great QAM constellation points are more frequently used in practical systems, for example, the 64-QAM constellation points used in wireless LANs and the 256-QAM constellation points used in the European DVB-T2 system. These constellation points all have high demodulation thresholds, so that weak multipath in the transmission environment will have significant effect on their determination. Nevertheless, virtual carriers employed in OFDM systems that include cyclic prefix make weak paths of low energies sometimes be drowned in energy leakage of strong paths and cannot be easily detected, making the channel noise reduction of high QAM reception systems more difficult. In fact, the channel noise reduction process will lead to channel distortion while reducing the noise. As noise reduction is good for demodulation and channel distortion is bad for demodulation, the result of the channel noise reduction process is depended on the combined effect of the above two opposing effects.
FIG. 1 illustrates the frame structure of a multi-carrier transmission mode in 802.11a/g systems. The frame consists of four parts wherein a first part is a short training sequence; a second part is a long training sequence; a third part is a signaling sequence; and a fourth part is a data sequence. The short training sequence is composed of 10 duplicate short training symbols and is mainly used for signal gain adjustment, signal capture and coarse estimation of carrier frequency offset. The following long training sequence is composed of 2.5 duplicate long training symbols and is mainly used for accurate estimation of carrier frequency offset, accurate timing synchronization of OFDM symbols and multipath estimation of transmission channel. The following signaling sequence is used for transmitting indication information which is necessary for the demodulation of the data sequence. Such indication information may include the length of the data sequence as well as the modulation mode used in transmission and the coding efficiency. Once the receiver obtains the above mentioned necessary information, it will be able to correctly demodulate and detect the data sequence.
In the 802.11a/g multi-carrier mode, channel estimation is accomplished during the period of receiving the long training sequence. The frequency domain channel response is obtained by dividing the received long training sequence by the locally stored frequency domain long training sequence. Since the frequency domain channel contains noise in most cases, if the channel is directly used for subsequent demodulation operation, it will result in a poor demodulation performance, therefore a noise reduction process is usually performed to the channel to improve operation threshold of system.

Low-complexity channel noise reduction method and apparatus for multi-carrier mode in wireless LANS

Omnivision Technologies (Shanghai) Co., Ltd.


Methods and systems produce petroleum products by insulating a thermal hydrocarbon recovery process from heat loss to surrounding areas of a formation utilizing an insulating composition including a non-gaseous phase component introduced into the reservoir that is different from water and insoluble in the hydrocarbons. The insulating composition may be disposed in the reservoir adjacent to where the heat loss is desired to be limited. In addition, the insulating composition may be disposed in a thief zone and may also be from an agent activated to form the composition at such desired locations by selecting activation dependent on at least one of temperature, time delay and oil saturation.

Bitumen recovery from oil sands presents technical and economic challenges due to high viscosity of the bitumen at reservoir conditions. Thermal recovery processes such as cyclic steam stimulation and steam assisted gravity drainage (SAGD) rely on injection of steam to heat the bitumen. The bitumen with reduced viscosity due to this heating then drains and is recovered.
Costs associated with energy requirements for generation of steam represent a significant portion of the overall operating expense. In addition, a typical SAGD operation may lose one third of the energy injected to overburden rock, underlying rock and/or thief zones, such as surrounding water and/or gas layers. Inefficiency due to such thermal losses limits economic returns.
Various approaches attempt to limit the thermal losses, but can present problems. For example, injection of non-condensable gases may form an insulating layer to the overburden. The gases fail to mitigate underlying thermal losses and may accumulate impairing heat transfer from the steam to the bitumen, decreasing temperature of the drainage interface due to partial pressure impact, and decreasing effective permeability to oil as a result of increased gas saturation.
Therefore, a need exists for methods and systems for recovering hydrocarbons from oil sands that are energy efficient.

Oil recovery with insulating composition


A marketing campaign management system that includes a campaign platform that categorizes intended recipient profiles corresponding to intended recipients of marketing campaign messages based on their levels of fatigue. Recipient profiles categorized as “saturated” are then sub-segmented to determine their relative levels of fatigue or saturation. The intended recipient profiles that are most fatigued are removed from a recipients list such that they will not be sent any campaigns until after a rest state has been completed. A transitional safe state ensures that the intended recipient profiles inserted back into the list are not immediately removed once again.

The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
In the pursuit of capturing consumer's attention, marketers reach out to their audience via different channels. Marketers commonly connect with recipients via one or more of emails, text messaging, social media advertisements, and website advertisements, among other channels.
This inefficient, "scattershot" approach contributes to network congestion as every marketer has to reach out to all of their potential customers over as many channels as possible to ensure the greatest possible audience.
Moreover, since there is no coherence in the cross-channel messaging, and the cadence at which these messages are sent is too frequent, it can lead to steep decrease in response rates.
When many individuals begin to feel overwhelmed or they frequently see messages from brand, it causes fatigue which can lead to some serious issues, such as:    1. Recipients skipping over messages or deleting them;    2. Increase in spam complaints;    3. Lower response rates with clicks and conversions being lower;    4. High unsubscribe rates; and    5. Negative sentiment towards the brand
Others have attempted to manage marketing campaign performance. For example, marketers monitor their marketing channels for "unsubscribe" rates on a periodic basis (e.g., month over month). Increases in unsubscribe rates can be indicative of recipient fatigue and alludes to a high churn rate. However, the approach is passive and only diagnoses a problem after the damage has already occurred. Additionally, computing and networking resources are wasted marketing to already-fatigued recipients until the moment the recipient unsubscribes.
Thus, there is still a need for marketing campaign systems that maximize audience engagement while optimizing the computing and network resources it consumes.

Network management based on marketing message fatigue