1. Field
The present application relates generally to wireless communications, and more specifically to systems, methods, and devices having wireless dual concurrent bands (DCB) or multiple concurrent bands (MCB), including operations achieving higher overall throughput and improving communication efficiency via band and/or channel switching and buffer management.
2. Background
In many telecommunication systems, communications networks are used to exchange messages among several interacting spatially-separated devices. Networks may be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks may be designated respectively as a wide area network (WAN), metropolitan area network (MAN), local area network (LAN), or personal area network (PAN). Networks also differ according to the switching/routing technique used to interconnect the various network nodes and devices (e.g., circuit switching vs. packet switching), the type of physical media employed for transmission (e.g., wired vs. wireless), and the set of communication protocols used, e.g., Internet protocol suite, Synchronous Optical Networking (SONET), Ethernet, etc.
Wireless networks are often preferred when the network elements are mobiles and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology. Wireless networks may employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.
The devices in a wireless network may transmit/receive information between each other. The information may include packets, which in some aspects may be referred to as data units. The packets may include overhead information (e.g., header information, packet properties, etc.) that helps in routing the packet through the network, identifying the data in the packet, processing the packet, etc., as well as data, for example user data, multimedia content, etc. as might be carried in a payload of the packet.
Recent evolutions of IEEE 802.11 standard expand Wi-Fi onto multiple frequency bands. These bands include: 2 GHz frequency band for IEEE 802.11b/g/n, 5 GHz frequency band for IEEE 802.11a/n/ac, 60 GHz frequency band for IEEE 802.11ad, 900 MHz frequency band for IEEE 802.11ah and TVWS band for IEEE 802.11af. Recent technology enables a wireless device to concurrently operate on multiple bands. With a MCB station (STA) and a MCB access point (AP), multiple links may be established between the STA and the AP. Many Wi-Fi products support DCB, usually including the 2 GHz frequency band and 5 GHz frequency band. A DCB STA and a DCB AP may operate on both frequency bands concurrently and achieve higher overall throughput. However, such a DCB operation mode may cause higher power consumption, and therefore may not be beneficial. Therefore, it would be desirable if a DCB STA or a MCB STA can switch an operation frequency band with an associated AP dynamically.


The steroid hormone cortisol is a key regulator of many physiological processes. However, an excess of cortisol, as occurs in Cushing's Disease, provokes severe metabolic abnormalities including: type 2 diabetes, cardiovascular disease, obesity, and osteoporosis. Many patients with these diseases, however, do not show significant increases in plasma cortisol levels. In addition to plasma cortisol, individual tissues can regulate their glucocorticoid tone via the in situ conversion of inactive cortisone to the active hormone cortisol. Indeed, the normally high plasma concentration of cortisone provides a ready supply of precursor for conversion to cortisol via the intracellular enzyme 11-beta-hydroxysteroid dehydrogenase type I (11beta-HSD1).
11beta-HSD1 is a member of the short chain dehydrogenase superfamily of enzymes. By catalyzing the conversion of cortisone to cortisol, 11beta-HSD1 controls the intracellular glucocorticoid tone according to its expression and activity levels. In this manner, 11beta-HSD1 can determine the overall metabolic status of the organ. 11beta-HSD1 is expressed at high levels in the liver and at lower levels in many metabolically active tissues including the adipose, the CNS, the pancreas, and the pituitary. Taking the example of the liver, it is predicted that high levels of 11beta-HSD1 activity will stimulate gluconeogenesis and overall glucose output. Conversely, reduction of 11beta-HSD1 activity will downregulate gluconeogenesis resulting in lower plasma glucose levels.
Various studies have been conducted that support this hypothesis. For example, transgenic mice expressing 2× the normal level of 11beta-HSD1 in only the adipose tissue show abdominal obesity, hyperglycemia, and insulin resistance. (H. Masuzaki, J. Paterson, H. Shinyama, N. M. Morton, J. J. Mullins, J. R. Seckl, J. S. Flier, “A Transgenic Model of Visceral Obesity and the Metabolic Syndrome”, Science, 294:2166-2170 (2001). Conversely, when the 11beta-HSD1 gene is ablated by homologous recombination, the resulting mice are resistant to diet induced obesity and the accompanying dysregulation of glucose metabolism (N. M. Morton, J. M. Paterson, H. Masuzaki, M. C. Holmes, B. Staels, C. Fievet, B. R. Walker, J. S. Flier, J. J. Mullings, J. R. Seckl, “Novel Adipose Tissue-Mediated Resistance to Diet-induced Visceral Obesity in 11β-Hydroxysteroid Dehydrogenase Type 1-Deficient Mice”, Diabetes, 53: 931-938 (2004). In addition, treatment of genetic mouse models of obesity and diabetes (ob/ob, db/db and KKAy mice) with a specific inhibitor of 11beta-HSD1 causes a decrease in glucose output from the liver and an overall increase in insulin sensitivity (P. Alberts, C. Nilsson, G. Selen, L. O. M. Engblom, N. H. M. Edling, S. Norling, G. Klingstrom, C. Larsson, M. Forsgren, M. Ashkzari, C. E. Nilsson, M. Fiedler, E. Bergqvist, B. Ohman, E. Bjorkstrand, L. B. Abrahmsen, “Selective Inhibition of 11β-Hydroxysteroid Dehydrogenase Type I Improves Hepatic Insuling Sensuitivity in Hyperglycemic Mice Strains”, Endocrinology, 144:4755-4762 (2003)). Furthermore, inhibitors of 11beta-HSD1 have been shown to be effective in treating metabolic syndrome and atherosclerosis in high fat fed mice (Hermanowoki-Vosetka et al., J. Eg. Med., 202(4):517-527 (2002)). Based in part on these studies, it is believed that local control of cortisol levels is important in metabolic diseases in these model systems. In addition, the results of these studies also suggest that inhibition of 11beta-HSD1 will be a viable strategy for treating metabolic diseases such as type 2 diabetes, obesity, and the metabolic syndrome.
Lending further support to this idea are the results of a series of preliminary clinical studies. For example, several reports have shown that adipose tissue from obese individuals has elevated levels of 11beta-HSD1 activity. In addition, studies with carbenoxolone, a natural product derived from licorice that inhibits both 11beta-HSD1 and 11beta-HSD2 (converts cortisol to cortisone in kidney) have shown promising results. A seven day, double blind, placebo controlled, cross over study with carbenoxolone in mildly overweight individuals with type 2 diabetes showed that patients treated with the inhibitor, but not the placebo group, displayed a decrease in hepatic glucose production (R. C. Andrews, O. Rooyackers, B. R. Walker, J. Clin. Endocrinol. Metab., 88:285-291 (2003)). This observation is consistent with the inhibition of 11beta-HSD1 in the liver. The results of these preclinical and early clinical studies strongly support the concept that treatment with a potent and selective inhibitor of 11beta-HSD1 will be an efficacious therapy in patients afflicted with type 2 diabetes, obesity, and the metabolic syndrome.


The present invention relates to a process for producing fiber-reinforced silicon carbide composites. Specifically, the present invention relates to a process for producing fiber-reinforced silicon carbide composites which are suitable for a variety of applications requiring improved toughness, such as aerospace high-temperature structural members, gas turbine members, fusion reactor materials, furnace members, heater materials, and artificial bones.
Silicon carbide ceramics are light-weight and are excellent in, for example, heat resistance, abrasion resistance, and corrosion resistance; they have recently come into wide use as, for instance, high-temperature corrosion-resistant members, heater members, abrasion resistant members, as well as abrasives and grindstones. Such silicon carbide ceramics are, however, low in fracture toughness, and have not yet been used in practice as structural members for use at high temperatures.
Ceramic composites compounded with fibrous reinforcements to improve the toughness of such ceramics have been intensively investigated in recent years. Such fiber-reinforced silicon carbide composites are generally manufactured by, for example, (1) an organometallic polymer impregnation pyrolysis (PIP) process, (2) a chemical vapor infiltration (CVI) process, and (3) infiltration of molten silicon (reaction sintering process).
However, the organometallic polymer impregnation pyrolysis (PIP) process has the following disadvantages in practice. According to this process, only low density and low strength can be obtained by a single impregnation, and the impregnation and pyrolysis procedure must be repeated about ten times to reduce the open porosity to 10% or less to and thereby improve strength characteristics. The process therefore requires a long time for production. The chemical vapor infiltration process (2) can provide products having complicated shapes at comparatively low temperatures of about 1100xc2x0 C., but it requires a very long time, of as much as several months, for infiltration, and gases used therefore are toxic. In addition, composites having an open porosity not exceeding 5% cannot be significantly obtained by the single use of the process (1) or (2).
In contrast, the reaction sintering process (3) requires only a short reaction time and can yield dense composites in a short time period. According to a process employed in Deutsche Forschungs-und Versuchsanstalt fur Luft-und Raumfahrt (DLR), a carbon fiber-reinforced carbon-silicon carbide composite is produced by infiltrating molten silicon into cracks of a carbon-fiber-reinforced carbon composite (C/C composite) to convert part of the matrix carbon into silicon carbide. This process utilizes a phenomenon in which glassy carbon does not react significantly with molten silicon to avoid the reaction between the carbon fiber and the silicon. In the process, however, the mechanical properties depend to a large degree on shapes of the cracks, which shapes in turn depend, for example, on the type of the carbon fiber and on the heat treatment temperature. High mechanical properties can therefore only be provided under specific production conditions suitable for the fiber to be used. The reaction sintering process (3) also includes a process of infiltrating molten silicon into a composite of a carbon powder and a fiber, which is performed by General Electric Co., USA, and Toshiba Corporation, Japan. This process is also disadvantageous in that a large quantity of silicon must be infiltrated, which invites free silicon to remain in large amounts of about 15%, or causes a reaction between the fiber and silicon unless the fiber is coated with boron nitride (BN) or the like.
After investigations on similar ceramic composites, the present inventors previously found that a unidirectional carbon-fiber-reinforced silicon carbide composites having a flexural strength of about 200 to 300 MPa even though having a large open porosity of 30% can be produced by compounding a matrix of a mixture of silicon powder and phenol resin with carbon fiber, and firing the composite in an inert atmosphere. The resultant composite contains a matrix of silicon carbide formed by reaction sintering (Japanese Patent No. 2045825). According to the reaction, however, only porous composites having a large open porosity can be obtained, as the volume of the matrix decreases about 38%. They also found that a unidirectionally carbon-fiber-reinforced silicon carbide composite having a flexural strength of about 500 to 600 MPa, even though it has a large open porosity of about 20%, can be produced by reducing the particle of the silicon powder about 5 xcexcm or below and by adding an organometallic polymer (Japanese Patent No. 2735151), and that a two-dimensional fiber-reinforced composite having a relatively large open porosity of about 15% as a two-dimensional fiber-reinforced silicon-carbide carbon composite, but having a flexural strength of about 300 MPa, can be obtained by heat-treating a green body containing a fibrous woven fabric reinforcement at a temperature at which silicon does not react with carbon, repeating impregnation and carbonization of a phenol resin, and finally forming silicon carbide (Japanese Patent No. 2879675).
It is an object of the present invention to solve the various problems in the production of fiber-reinforced silicon carbide composites according to the conventional silicon melt infiltration technique, and to provide a process for producing fiber-reinforced silicon carbide composites, which process can easily yield a composite having a high toughness even if they are to have complicated shapes.
Specifically the invention is directed to provide a process for easily producing fiber-reinforced silicon carbide composites even if they are to have complicated shapes, by covering a fiber bundle region with glassy carbon derived from resin, forming a porous region in a specific portion of a matrix by a reaction between silicon powder and carbon derived from the resin to form silicon carbide, which reaction is accompanied by volumetric reduction, and subjecting the porous region to infiltration of molten silicon. The resultant fiber-reinforced silicon carbide composite is high in toughness and its strength is not deteriorated, without coating the fiber surface with, for example, BN.
After intensive investigations on the production of fiber-reinforced silicon carbide composites to achieve the above objects, the inventors found that a dense fiber-reinforced silicon carbide composite showing nonlinear fracture can be obtained by preparing and molding a prepreg including silicon powder, carbon source resin and fiber to yield a green body, or laminating a prepreg containing resin with a prepreg containing silicon powder and resin in alternate order and molding the laminate to yield a green body; carbonizing the molded green body at a temperature of about 900xc2x0 C. to 1350xc2x0 C. in an inert atmosphere; preferably, impregnating the carbonized composite with a resin and carbonizing the impregnated composite at a temperature of about 900xc2x0 C. to 1350xc2x0 C. in an inert atmosphere, and repeating this impregnation-carbonization procedure; subjecting the composite to reaction sintering at a temperature of about 1300xc2x0 C. or higher in vacuo or in an inert atmosphere, and finally infiltrating molten silicon into the sintered composite at a temperature of about 1300xc2x0 C. to 1800xc2x0 C. in vacuo or in an inert atmosphere. The present invention has been accomplished on the basis of the above findings.
Specifically, in the process for producing a fiber-reinforced silicon carbide composite of the invention, (i) a mixture of silicon powder, a carbon source resin and reinforcement fiber is carbonized in an inert atmosphere, and the resultant carbonized composite is impregnated with resin and is subjected to carbonization or the like, or (ii) a mixture of (a) a matrix containing silicon powder and carbon source resin, and porous fiber as a container, and (b) reinforcing fiber containing carbon source resin is carbonized in an inert atmosphere, and the carbonized composite is impregnated with a resin and subjected to carbonization or the like. By the procedure of (i) or (ii), carbon in a fiber bundle region as a reinforcement is densified to prevent the fiber from reacting with molten silicon, then open pores are formed in a matrix region by reaction sintering, and molten silicon is infiltrated into only the open pores in the matrix in vacuo or in an inert atmosphere.
According to the inventive process, dense fiber-reinforced silicon carbide composites can be easily obtained without deteriorating the strength of the fiber, even if they are of complicated shape.
Preferred carbon source resins to be used in the invented process include, but are not limited to, phenol resins, furan resins, pitch, and polycarbosilane and other organometallic polymers. Each of these resins may be used alone or in combination. The resin may further include, for instance, a carbon powder, a graphite powder, carbon black, or an aggregate; and/or an antioxidant such as silicon carbide, silicon nitride, mullite, molybdenum disilicide, molybdenum, boron carbide, or boron powder.
The silicon may be either pure metallic silicon or a silicon alloy with, for example, magnesium, aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, or molybdenum.
In addition, a fibrous woven fabric reinforcement is employed in the invented process, and preferred fibrous woven fabrics to constitute the fibrous reinforcement include, but are not limited to, woven fabrics of carbon fibers, silicon carbide fibers, silicon nitride fibers, and oxide fibers. The carbon fibers may be either of pitch fibers or acrylonitrile fibers. Each of these fibrous woven fabrics can be used independently or in combination. Nonwoven fabrics or laminates of transversely laid sheet-like unidirectional fiber prepregs may also be used instead of fibrous woven fabrics.
As the fiber in the matrix to contain the silicon powder and resin, porous woven or nonwoven fabrics are preferred composed of, for example, carbon fibers, silicon carbide fibers, silicon nitride fibers or oxide fibers, as well as porous sheets composed of carbon, silicon carbide, a resin or a plastic. The use of the container can be omitted by coating a resin-impregnated woven fabric prepreg with a mixture of silicon powder and carbon source resin.
According to the inventive process as described above, dense fiber-reinforced silicon carbide composites can easily be produced by covering a fiber bundle region of a two-dimensional fiber reinforced silicon carbide composite with amorphous carbon derived from an impregnated resin to densify the region; forming open pores in spaces between the fibers or between the fibrous woven fabrics with the use of reaction sintering of, for example, a phenol resin with silicon powder; and infiltrating molten silicon into the open pores.
In addition, and advantageously, the invented process can easily yield green bodies (molded parts) having complicated shapes because hot pressing or other techniques are not required. Furthermore, the process can yield dense composites without deteriorating the fiber, as molten silicon is infiltrated in the last step.
Next, preferred embodiments of the present invention will be described.
According to the first embodiment of the invented process (hereinafter simply referred to as xe2x80x9cthe first processxe2x80x9d), a continuous woven fabric as a fibrous reinforcement is impregnated with dissolved resin, is dried, and is further impregnated with a slurry of a mixture of resin and a silicon powder; is dried to give a prepreg; and the prepreg is molded into a desired shape. The molding is carried out by, for example, dissolving resin in suitable solvent, impregnating a continuous fiber woven fabric with the resin solution, removing the solvent by drying, separately preparing a slurry composed of resin, silicon powder and solvent, impregnating continuous fiber woven fabric with the slurry, removing the solvent by drying, molding the dried product in an appropriate die at a temperature of, generally, about 100xc2x0 C. to 250xc2x0 C. into a desired shape. In this procedure, the dissolved liquid resin is incorporated into spaces between fiber bundles, but the powdered silicon, which generally has a relatively large particle size of about 10 xcexcm, is unevenly distributed and present only in spaces between the fibrous woven fabric.
In addition, and advantageously, the following process according to the second embodiment (hereinafter simply referred to as xe2x80x9cthe second processxe2x80x9d) is also effective. According to the second process, continuous fiber woven fabric as a fibrous reinforcement is impregnated with dissolved resin, and is dried to give fiber prepregs; separately, a slurry is prepared by mixing resin and silicon powder, nonwoven fabric is impregnated with the slurry, and is dried to give matrix prepregs; and the fiber prepregs and the matrix prepregs are laminated in alternate order, and the laminate is molded into a desired shape. The laminate may have each layer comprising a plurality of individual prepregs. The molding can be performed by, for example, dissolving a resin in a suitable solvent, impregnating continuous fiber woven fabric with the resin solution, removing the solvent by drying to give fiber prepregs, separately preparing a slurry from resin, silicon powder and a solvent, impregnating nonwoven fabric with the slurry, removing the solvent by drying to give matrix prepregs, laminating an each an adequate number of these prepregs in alternate order, and molding the laminate in an appropriate die at a temperature of, generally, about 100xc2x0 C. to 250xc2x0 C. into a desired shape.
The silicon powder to be used in the invented process is preferably fine powder, and particularly fine powder having a mean particle size not exceeding 20 xcexcm. Silicon powders having a relatively large diameter should preferably be pulverized with, for example, a ball mill, before use.
The obtained green body (molded body) is then carbonized at a temperature of about 900xc2x0 C. to 1350xc2x0 C. in an argon or other inert atmosphere to avoid the reaction of carbon derived from the resin with silicon. The carbonized composite has regions composed of the resin alone, and regions composed of a mixture of the silicon powder and carbon derived from the resin, but it has a high porosity, because the resin is pyrolyzed into carbon.
The fired body is impregnated with a resin solution in vacuo or under pressure, and is carbonized at a temperature of about 900xc2x0 C. to 1350xc2x0 C. in an argon or other inert atmosphere to avoid the reaction of carbon derived from the resin with silicon. A combination procedure of the resin impregnation and carbonization is repeated a predetermined number of times, preferably one to five times, and the resultant composite is fired at a temperature of 1300xc2x0 C. or higher in vacuo or in an argon or other inert atmosphere to react carbon derived from the resins with silicon to form porous silicon carbide in spaces between the fiber woven fabric.
A composite is thus obtained comprising fiber bundles coated with dense carbon so as not to react with molten silicon, and a porous silicon carbide matrix between layers of the fiber woven fabric.
The composite is heated to a temperature of about 1300xc2x0 C. to 1800xc2x0 C. in vacuo or in an inert atmosphere to infiltrate molten silicon into open pores of the composite (fired body), which open pores include the porous silicon carbide matrix between the layers of the fiber woven fabric, to give a fiber reinforced silicon carbide composite. The reaction sintering of silicon with carbon and infiltration of molten silicon can be performed in the same heat treatment.
The proportion of the silicon powder to the resin to be used in the inventive process should preferably be selected from such a range that the atomic ratio of silicon to carbon derived from the resin, Si/C, ranges from 0.1 to 4. The prepregs may be prepared by, as described above, coating the fabric with phenol resin or another resin alone, and coating the coated fabric with a slurry containing silicon powder and phenol resin or another resin. In other words, the proportion of silicon to carbon in the composite can be distributed unevenly. The proportion of silicon carbide matrix to the fiber woven fabric reinforcement in the fiber-reinforced composite can be freely selected according to the application of the composite, but generally, the fiber occupies about 15% to 65% by volume in the composite.
In the invention, the prepreg containing the reinforcing fiber woven fabric can be prepared by any of the following techniques: (i) a technique of using resin from the beginning to yield a prepreg, as described above; (ii) a technique which comprises laminating a container for silicon powder and resin, or silicon powder and aggregate powder with a fiber woven fabric containing no resin to yield a green body, and impregnating the green body with resin to yield a preform; and (iii) a technique which comprises laminating a container for neither silicon nor resin with reinforcing fiber woven fabric containing resin to yield a green body, and impregnating the green body with a slurry containing silicon powder and resin.
Another resin impregnation can be performed after the reaction sintering of carbon from phenol resin or other resin with silicon powder, which is completed at temperatures of 1300xc2x0 C. or higher. Separately, the reaction sintering can be conducted prior to, or concurrently with, the infiltration of molten silicon.


In recent years, we have greeted the age of multimedia in which audio, video, and other data are integrally handled, and the conventional information media, i.e., means for transmitting information between persons, such as newspapers, magazines, televisions, radios, and telephones, have been grasped as subjects of multimedia. Generally, “multimedia” does not mean only representing characters, but means representing especially images, simultaneously in relation with diagrams, speech, and the like. In order to adopt conventional information as information media as subjects of multimedia, it is required to represent the information in a digital form.
When the information quantity possessed by the respective information media described above are estimated as digital information quantity, the information quantity per character is 1-2 bytes, while the information quantity of more than 64 kbits per second (telecommunication quality) is required for audio and the information quantity of more than 100 Mbits per second (current television broadcasting quality) is required for moving picture. Therefore, it is not practical to handle such tremendous amounts of data of the above-described information media as they are in digital formats. For example, though visual phones have already been put to practical use by ISDN (Integrated Services Digital Network) having a transmission rate of 64 kbps˜1.5 Mbps, it is impossible to transmit images of television cameras as they are by the ISDN.
In these circumstances, information compression techniques are required. For example, in the case of visual telephones, the moving picture compression techniques standardized as H.261 and H.263 by ITU-T (International Telecommunication Union-Telecommunication Sector) are employed. Further, according to the information compression technique of MPEG1, it is possible to contain video information together with audio information in an ordinary music CD (compact disk).
MPEG (Moving Picture Experts Group) is an international standard of data compression for a moving picture, i.e., pixel values of a moving picture. MPEG1 is a standard for compressing pixel values of a moving picture to 1.5 Mbps, i.e., data of a television signal to about 1/100. Further, while the transmission rate in MPEG1 is mainly limited to about 1.5 Mbps, in MPEG2 which is aimed at standardization to meet a request for a higher image quality, the limitation is relaxed with pixel values of a moving picture being compressed to 2˜15 Mbps.
Further, under the existing circumstances, standardization of MPEG4 has been almost completed by the working group for standardization of MPEG1 and MPEG2 (ISO/IEC JTC1/SC29/WG11), which enables coding and handling in object units and realizes new functions demanded in the multimedia age. While MPEG4 has initially aimed at standardization of a coding method of a low bit rate, the aim of the standardization thereof is now extended to a more versatile coding process of a high bit rate or an interlaced image. One of characteristics of MPEG4 is coding simultaneously plural image sequences and transmitting the same. This enables one image scene to be composed of plural images. The foreground and the background can be different image sequences, and the frame frequency, the image quality and the bit rate thereof can be individually changed. Thereby, plural images can be arranged in the horizontal or vertical direction like in a multi-screen, and it is enabled for the user to extract or enlarging-display only a desired image. It is general that only pixel values are coded for the background similarly in MPEG2, while, as for the foreground, a pixel value signal indicating pixel values of the object as well as a shape signal indicating the shape of the object are coded. Commonly, the coding of the foreground are known as coding in object units. The displayed image is a video composed of the respective decoded images.
FIGS. 8(a)-8(f) are diagrams for explaining video composition in object units. FIG. 8(a) shows pixel values of a foreground video (hereinafter, simply referred to as foreground) fv1 of a balloon which composes a display video. FIG. 8(b) shows a shape value of a shape signal fml corresponding to the foreground fv1 in FIG. 8(a). FIG. 8(c) shows pixel values of a foreground fv2 of a human which composes the display video. FIG. 8(d) shows a shape value of a shape signal fm2 corresponding to the foreground fv2 in FIG. 8(c). FIG. 8(e) shows pixel values of a background video (hereinafter, simply referred to as background) rv. FIG. 8(f) shows the display video which is obtained by composing the foregrounds fv1 and fv2 of FIGS. 8(a) and 8(c) with the background rv of FIG. 8(e).
In the screens of the shape signals of FIGS. 8(b) and 8(d), parts painted black in the screens show areas in which the corresponding pixel values exist, i.e., inside an object, and white parts show areas in which no corresponding pixel values exist, i.e., outside the object. A wording that “a pixel value is significant/insignificant” is sometimes used in a sense that a pixel value exists/no pixel value exists.
FIG. 9 is a block diagram illustrating a structure of a prior art video decoding system. In this figure, reference DeMux denotes a stream demultiplexer for demultiplexing a multiplexed stream StrM. References Dec1, Dec2 and Dec3 denote decoders for decoding video streams Str1, Str2 and Str3 which have been demultiplexed by the stream demultiplexer DeMux, respectively. Reference Comp1 denotes a video composer for composing decoded videos Dout1, Dout2 and Dout3 which have been decoded by the decoders Dec1, Dec2 and Dec3, respectively. Reference Disp denotes a display unit for displaying a video Vcom which is composed by the video composer Comp1. Reference IF denotes an object selector for the user to select an object. CPU denotes a controller for controlling the decoders Dec1, Dec2 and Dec3 in accordance with the instruction of the object selector IF.
Next, the operation of the prior art video decoding system is described. A multiplexed stream StrM is demultiplexed by the stream demultiplexer DeMux into video streams Str1, Str2 and Str3 corresponding to videos of three objects, as well as overlap information Odr indicating the order of overlap of these videos which is sent to the controller CPU. The decoder Dec1 decodes the video stream Str1 and outputs the decoded video Dout1. Similarly, the decoders Dec2 and Dec3 decode the video streams Str2 and Str3, and output the decoded videos Dout2 and Dout3, respectively. The video composer Comp1 composes these decoded videos Dout1, Dout2 and Dout3 to provide a composed video Vcom, and displays the composed video on the display unit Disp.
On the other hand, in the case of object unit coding, the user can switch the display/non-display of videos in object units. The user selects the display or non-display of each object by means of the object selector IF. The object selector IF notifies the video composer Comp1 of object non-display information Dsel according to this selection, and the video composer Comp1 composes only videos of objects which should be displayed, to display the composed video.
With using the shape value of an object, it can be judged whether a position is inside or outside the object. Accordingly, by executing an operation of selecting a button Bn within the screen using a pointer Pr as shown in FIG. 10, it is possible that the user designates a specific position in the screen and obtains information as to whether the position is inside or outside an object. To be specific, the user moves the pointer by the object selector IF and selects a button, thereby notifying the controller CPU of object selection information Psel which indicates a designated pixel position. The controller CPU makes an inquiry to the decoders Dec1, Dec2 and Dec3 corresponding to the respective objects with object judge commands Q1, Q2 and Q3 about whether the designated position is inside or outside an object such as a button on the screen. The decoders Dec1, Dec2 and Dec3 report the controller CPU whether the inquired position is inside or outside the object by object judge results A1, A2 and A3, respectively, and then the controller CPU notifies the user or applications of the object judge results A1, A2 and A3 collectively as object judge result Req.
The block diagram of FIG. 9 illustrating the video decoding system shows an example where three videos are composed to obtain a composed video Vcom, while the number of videos to be composed can be less than three, or more than three. In addition, in this example, one decoder is provided for each video stream, while when plural video streams can be decoded by one video decoder by time division or the like, the number of video decoders can be properly reduced.
FIG. 11 is a block diagram illustrating a structure of the decoder Dec of the video decoding apparatus in the prior art video decoding system shown in FIG. 9. In this figure, a video stream Str, an object judge command Q, an object judge result A and a decoded video Dout correspond to one of the video streams Str1, Str2 and Str3, the object judge commands Q1, Q2 and Q3, the object judge results A1, A2 and A3, and the decoded videos Dout1, Dout2 and Dout3 in FIG. 9, respectively. Reference DecU denotes a video decoding unit for decoding the video stream Str. References MEM1, MEM2, MEM3 and MEM4 denote memories for containing decoded videos mem1, mem2, mem3 and mem4, respectively.
Next, the operation of the decoder Dec is described. In FIG. 11, the video decoding unit DecU decodes the video stream Str and stores the decoded videos mem1, mem2, mem3 and mem4 which are obtained by the decoding, into the memories MEM1, MEM2, MEM3 and MEM4, respectively. At this time, when the video stream Str has been inter-frame coded, the decoded videos mem1, mem2, mem3 and mem4 are read from the memories MEM1, MEM2, MEM3 and MEM4 to utilize the same as reference videos at the motion compensation. Since a signal of a video having the shape is composed of three components indicating the color (YUV, RGB or the like) and a shape value A, i.e., four components in total, the four individual memories are provided to correspond to the four components, respectively. However, when practically packaged, these can be integrated in one memory.
In the example shown in FIG. 11, the memories MEM1, MEM2, MEM3 and MEM4 contain a luminance pixel value Yimg, two color difference pixel values Uimg and Vimg, and a shape value Aimg, respectively. Since the shape value Aimg is stored in the memory MEM4, when a pixel position such as a position pointed by the pointer is indicated by the object judge command Q from the controller CPU in FIG. 9, the memory MEM4 judges whether that position is inside or outside the object, and outputs the result as the object judge result A. The decoded videos stored in the memories MEM1, MEM2, MEM3, and MEM4 are read as pixel decoded videos Yimg, Uimg and Vimg, and a shape decoded video Aimg at a timing of display, to obtain pixel decoded videos Yout, Uout and Vout, and a shape decoded video Aout, respectively. The decoded video Dout is obtained by combining the pixel decoded videos Yout, Uout and Vout and the shape decoded video Aout.
FIG. 12 is a diagram showing an internal structure of the memory MEM4 which contains the shape value. In this figure, reference MEM41 denotes a shape signal storage memory for containing the shape signal. Reference CMP denotes a pointed position comparison means for comparing and judging whether the pointer operated by the object selector IF in FIG. 9 points inside or outside of an object, such as a button.
Next, the operation of the memory MEM4 is described. In FIG. 12, the shape signal storage memory MEM41 contains the shape signal mem4 which has been decoded by the decoding unit DecU in FIG. 11 as a bitmap. The pointed position comparison means CMP converts pointed position information of the pointer operated by the object selector IF in FIG. 9, which is transmitted in accordance with the object judge command Q issued by the controller CPU in FIG. 11, together with this object judge command Q, into an address of the shape signal storage memory MEM41, and judges whether or not the bitmap of the shape signal exists at that address, thereby judging whether the position pointed by the pointer is inside or outside of the video of the object, such as a button. Then, the pointed position comparison means CMP outputs the judge result to the controller CPU in FIG. 9 as the object judge result A.
As described above, the information as to whether a position is inside or outside an object can be obtained by using the shape value of the object. By utilizing these workings, the shape value can be used as a GUI (Graphic User Interface) operable button whose shape varies. This is what is called a “hot spot”, and, for example, when a certain position on the screen of a terminal (for example, assuming that this is a video in a form of a button) is clicked to make the terminal execute a special processing, a shape signal indicating that position is transmitted as a moving picture, thereby changing the position or shape of the button. For that purpose, not only videos including both of pixel values and shape values, but also videos having only shape values are effective, and accordingly the coding of only shape values can be also used in MPEG4.
For example, when FIG. 8(f) is used as background, only shape values of FIGS. 8(b) and 8(d) are coded, and a position is pointed in FIG. 8(f) by a pointer, the judgement as to whether that position is inside or outside the human or balloon can be made. Therefore, when only the judgement as to whether a position is inside or outside the video is to be made, the coding of individual pixel values of FIGS. 8(a), 8(c) and 8(e) is not required, and only the coding of the pixel value of FIG. 8(f) is required. Therefore, the coding/decoding process can be simplified, and in some cases the compression rate can be also increased by reduction of the number of pixels to be coded.
From the above descriptions, it can be seen that there are three kinds of the stream of color videos (moving pictures) in MPEG4, i.e., only YUV (color signals) in the case of videos whose shapes do not vary, YUV+A (a shape signal is added to the color signals) in the case where coding in object units is carried out, and only A (shape signal) in the case of judgement as to whether a position is inside or outside a video is made.
There are some cases where videos are transmitted according to MPEG1 and a shape signal according to MEPG4 is added thereto. Further, there is also a case where a texture is pasted on a shape signal transmitted according to MPEG4, whereby MPEG4 and CG (Computer Graphics) are combined to display color videos.
FIG. 13 is a diagram schematically showing the format of a video stream Str corresponding to a video of an object. In FIG. 13, reference HD denotes the header of the entire stream. References DA1, . . . , and DAX denote data of one screen, respectively. References HD1, . . . , and HDX denote headers corresponding to the screen data DA1, . . . , and DAX, respectively.
In the header HD of the entire stream, the video size (when the size of the video does not vary with frames) and the coding method (quantization method or information relating to arrangement of data) as well as information indicating a target which is being coded (above-mentioned YUV, YUV+A, A or the like), are coded and stored.
In the headers HD1, . . . , and HDX corresponding to the screen data DA1, . . . , and DAX, respectively, parameters required for the decoding, information indicating which frame is the corresponding video data or which is of I frame and P frame the video data, and the like are coded and stored.
FIG. 14 is a diagram showing a structure of a multiplexed stream StrM which is obtained by multiplexing plural video streams Str each corresponding to a video of an object. In the example shown in FIG. 14, the video streams Str are time-divided multiplexed frame by frame, and a header MHD including the overlap information Odr is arranged between the video streams Str.
As described above, it is useful to code only shape values, while when a stream including no pixel value but having only the shape value is received, what becomes the pixel value which is obtained by decoding this stream is not decided in the MPEG4 standard at the present time.
Originally, a stream having only the shape value is created provided that it is not displayed on the receiving end. However, since the measures to be taken when this is received and decoded are not defined in the MPEG4 standard, the stream having only the shape value should not be displayed, in accordance with proposals on the application side which utilizes video communication to provide information terminals with various kinds of services.
However, in many cases, video decoders created for general purposes are generally used for various applications to reduce developing costs, and these video decoders are designed to always decode and display transmitted information. Therefore, also when receiving a stream having only the shape value, the video decoder decodes this stream, and some pixel values which cannot be predicted are displayed due to that decoding, thereby giving wrong or unpleasant feelings to persons who watch the screen.


Semiconductor integrated circuit devices are designed using various computer aided means to produce a logical circuit in which various functional elements are identified and interconnected to form particular logic functions. Computer-aided design (CAD) or other design tools are typically used to generate lithography data based on the design and the lithography data is used to form a photomask set that is used in the actual fabrication of the semiconductor integrated circuit (IC) devices.
A standard cell type semiconductor IC device is an application specific integrated circuit (ASIC) device designed using multiple standard cells. Each standard cell may include a group of transistor and interconnect structures that provide a boolean logic function (e.g., AND, OR, XOR, XNOR, inverters) or a storage function (flipflop or latch, for example). In a standard cell system, the standard cells are advantageously maintained in a library and various integrated circuit devices can be designed by selecting desired standard cells from the library and combining them in various arrangements to form a most suitable cell arrangement pattern that forms part of the layout of the integrated circuit device.
The design process for standard cell semiconductor IC devices includes constructing the integrated circuit design out of the selected standard cells that are connected together electrically, i.e. routed, using wire interconnects which are also used to route the cells to input and output terminals. The standard cells and connections between them may be stored in databases called “netlists” (i.e., lists of symbolic interconnections). The netlist describes the connectivity of the standard cells within the semiconductor IC device design. One or more computer-aided design (CAD) tools may be used to generate the netlist of the selected standard cells and the interconnections between the cells and input/output. The netlist may be used by a floor planner, placement tool, or other design tool, to place the selected cells at particular locations in the layout of a standard cell integrated circuit device.
The design of the standard cell semiconductor IC device may be carried out by an APR (automatic placement and routing) design tool that includes a placer and a router, by selecting standard cells from the library of standard cells and placing and routing the cells according to design instructions provided to the APR tool such as in the netlist. The placer determines the optimum location of each standard cell of the integrated circuit on the semiconductor substrate, and the router optimizes the routing of input/output lines and the connection between standard cells so that the integrated circuit layout does not become overly congested by input/output and other routing lines. Other CAD tools are also available and may be used in the design of standard cell semiconductor IC devices.
In addition to the standard cells that may be selected from a library, the device design may include other standard cells such as user specified target cells with different operational characteristics. When such target cells are used along with the standard cells from the library to form a standard cell semiconductor IC device, additional challenges in the placement and routing of the cells is imposed. Target cells that operate at higher power consumption levels, for example, require the routing wires used to couple the target cells to ground and power sources, to operate at high power levels and carrying high currents. As such, these wires are especially susceptible to electromigration (EM) failure and even complete blowout of the wire, thus representing a significant shortcoming of conventional technology.


A current transformer monitors a current that passes through an electrical apparatus such as a power transformer, a generator, or a circuit breaker. To ensure that a current transformer is accurately monitoring the current, the metering or the relaying accuracy of the current transformer is verified. The metering accuracy determines the ratio error and the phase angle of the current transformer through a stringent certification process established by the Institute of Electrical and Electronics Engineers (IEEE) under IEEE C57.13 (1993). In comparison, the relaying accuracy relates to measuring the secondary excitation and resistance associated with the current transformer. Generally, current transformers intended for relaying applications do not undergo the certification process under IEEE C57.13 unless the current transformer is retrofitted for a metering application.
Before an accuracy test can be performed under IEEE C57.13 (1993), the current transformer is disconnected and removed from its position within the electrical apparatus. In a traditional accuracy test, a current, referred to as a primary current, circulates through the primary winding of the current transformer and a known standard transformer of the same current ratio. The ratio and phase displacement errors of the current transformer are then determined by comparison to the known standard. This process consumes a substantial amount of time and incurs a significant cost due to removing the current transformer from its installation on or within the electrical apparatus. Frequently, it is more cost-effective to replace rather than test the existing current transformer. It is therefore desirable to have a test method that overcomes the disadvantages associated with conventional methods for determining the accuracy of a current transformer.


The present invention relates to scanners, and more specifically to a carriage positioning structure for a scanner which enables the scanner to pick up the image of an object placed thereon, or turned upside down to pick up the image of an object placed below it.
Regular scanners are commonly designed to pick up the image of flat sheets of document (2-dimensional scanning). If a sufficient depth of field is provided, a scanner can be used to pick up the image of a 3-D object. However, because regular scanners are commonly designed for 2-dimensional scanning, it is difficult to use a regular scanner to pick up the image of a 3-D object. When using a regular scanner to pick up the image of a 3-D object, the scanner may have to be turned upside down, however the image pick-up module (mechanism) cannot be stably reciprocated when the scanner is turned upside down.


1. Field of the Invention
The present invention relates to a semiconductor integrated circuit and an image processing apparatus having the same.
2. Description of the Related Art
According to a conventional technology for data transmission, a plurality of devices can be connected to a peripheral component interconnect (PCI) bus. One of the devices obtains a right to use the PCI bus, and such a device is determined as a master. The master device can transmit and receive data to and from any of the other devices.
Because the PCI bus employs a parallel transmission system, when the PCI bus receives a large amount of data, it is likely to cause a bottleneck. In order to overcome such a problem of the PCI bus, a technology called PCI Express (PCIe) has been proposed.
The PCIe allows point-to-point links between devices, and employs a serial transmission system.
The PCIe employs a full-duplex system in which transmission and reception of data are performed separately, and thereby the PCIe supports split transaction. Thus, the transmission and the reception of data can be performed at the same time. In the split transaction, a request and a response to the request are separately performed, and therefore a subsequent request can be issued before the response is obtained. In this manner, the transmission and the reception of data can be performed in an effective manner and at a high speed.
In the PCIe, a latency time of a read request to read data from a memory becomes longer. The latency time is a period starting from issuing the read request and ending at receiving the data from the memory. For this reason, a timing of issuing a read request affects the throughput efficiency of a bus in use for split transaction.
FIG. 10 is a schematic diagram for explaining transmission efficiency of a conventional PCIe. When write requests are continuously received from an arbiter in an application specific integrated circuit (ASIC) or the like, the write requests are first issued, and afterwards a read request is issued. Therefore, a reception line is in an idle state during a period T1, during which write requests and data corresponding to the write requests are sent via a transmission line. As a result, the conventional PCIe obtains low transmission efficiency.
FIG. 11 is a schematic diagram for explaining another example of transmission efficiency of a conventional PCIe. If the data transmission rate in an ASIC 5 is lower than the packet transmission speed of a PCIe 6, a request is sent to the PCIe after all of data corresponding to the request is stored in a data buffer that is arranged in a PCIe interface (I/F) circuit. Thus, it is possible to prevent data underflow. However, because a request cannot be sent to the PCIe before all the data is stored in the data buffer, the transmission line is in an idle state during a period T2. Occurrence of the period T2 causes the period T1 in the reception line to increase, and therefore the transmission efficiency becomes much lower.
The use of the PCIe makes it possible to perform the transmission and the reception of data separately and at the same time, nevertheless read data transmission can still be delayed.
A master (bus master device) often executes some operation on data that is read from a memory, and then writes the resultant data in the memory. Therefore, a delay in time for receiving read data from the memory causes a delay in an issue of a write request by the master. As a result, the throughput of the whole system is lowered.
According to a conventional technology disclosed in Japanese Patent Application Laid-Open No. 2006-154910, a memory controller selects a memory access request that allows continuous access to a memory upon sending a write request and a read request, and such continuous access achieves high-speed access to the memory. Furthermore, a plurality of read accesses is collectively processed as continuous read access, and a plurality of write accesses as continuous write access. A read cycle and a write cycle are alternately processed. Thus, it is possible to reduce the number of times of switching between a read access and a write access, and achieve high-speed access to the memory.
However, such a conventional technology has a problem if employed in the PCIe. Specifically, when write requests are collectively issued via a transmission line, a reception line is in an idle state. On the other hand, when read requests are collectively issued, a transmission line is in an idle state. As a result, utilization efficiencies of the transmission line and the reception line are decreased, and the throughput of the whole system is lowered.


1. Field of the Invention
The present invention relates to a smoking article comprising a carbon monoxide reducing agent and a method of manufacturing the same, and a method of manufacturing the carbon monoxide reducing agent.
2. Description of the Related Art
Carbon monoxide that is generated during combustion of a smoking article is a substance that is preferable to be removed. Conventionally, attempts to reduce carbon monoxide included in mainstream smoke that is generated during smoking or in sidestream smoke during natural combustion have been done by incorporating a catalyst, an oxidant, an adsorbent and the like into a tobacco filler, a tobacco wrapping paper, a filter and the like.
For example, Jpn. PCT National Publication No. 2008-502343 discloses that silver oxide is used as a catalyst for oxidizing carbon monoxide. Jpn. PCT National Publication No. 2007-527782 and Jpn. PCT National Publication No. 2007-527698 disclose a catalyst comprising metal particles and/or a metal oxide of a nanoscale carried on a fibrous carrier or a high-surface area carrier. Jpn. PCT National Publication No. 2005-527205 discloses an oxyhydroxide compound that acts as an oxidizing agent for converting carbon monoxide to carbon dioxide, and exemplifies an oxyhydroxide compound of a transition metal and the like.
However, use of a large amount of a noble metal or a transition metal as a metal causes increase in the manufacture cost of a catalyst. Furthermore, use of nanoscale particles may cause problems of difficult handling in the manufacture of smoking articles, increase in costs for pulverization, and the like. On the other hand, milliscale particles having a large particle size are difficult to be included into or carried by a smoking article in the manufacture.
Meanwhile, Jpn. Pat. Appln. KOKAI Publication No. 2006-122793 discloses a catalyst including a composite oxide comprising calcium and aluminum as main components and also comprising iron as a catalyst for a shift reaction of water gas. In that publication, a catalyst comprising a composite oxide comprising calcium and aluminum (calcium aluminate) as a main component is manufactured by manufacturing a layered double hydroxide including calcium and aluminum in an alkali aqueous solution in advance, and sintering the product by heating.
It is known that calcium aluminate generally causes a hydration reaction when contacting with water and causes aggregation and crystal breakup. Since the catalyst in Jpn. Pat. Appln. KOKAI Publication No. 2006-122793 has a large BET specific surface area of 20 m2/g or more, it has a very large contact surface area with water, and thus a hydration reaction proceeds rapidly from the surfaces of the catalyst particles and causes breakup of the crystal structure or coagulation of the composite oxide. As a result, the catalyst particles are deactivated within a short time period.


As populations grow and more and more vehicles flood the roadways, parking locations have become problematic in terms of scarcity and proximity to desired sites, particularly in urban settings. Likewise, the presence and operation of large amounts of fuel-burning vehicles leads to undesirable increased air pollution levels, particularly in crowded urban settings. Additionally, difficulties in locating parking spaces in such locations generally requires drivers to undertake prolonged searching for such a purpose, thus resulting, with cumulative numbers of such vehicles facing such a necessary experience, in higher pollution levels on average.
As well, the capability of municipalities to afford proper infrastructure for vehicle parking is typically undertaken through metering devices, although such systems require constant monitoring to ensure proper payments have been made to the necessary effect. In tandem, then, there is a growing issue pertaining to the difficulties inherent in the availability and proper revenue generation of sufficient parking places in such urban locations. Parking garages, decks, commuter lots and other secluded parking lots have been constructed in the past to meet a certain degree of drivers' parking demands. However, these structures and areas are generally limited in terms of locations, typically cost a flat fee for entry, regardless of time spent, or, alternatively, require hourly payments of certain high levels that must be paid before egress is permitted, all in a manner to recoup the costs involved with the overall construction, necessitate either human or mechanical intervention to guarantee payments are made, and other machinery to prevent driver egress until payments have been received (such as gate arms, for example). In essence, although such structures and parking areas have proven successful to a certain degree, there remains a need for other alternatives to drivers who do not wish to be beholden to such strictures.
In particular, as alluded to above, street parking, rather than lot parking, has been an attractive alternative to many drivers, specifically as a means to allow for parking in a vicinity closer to a specific target location, reducing individual costs, and increasing freedom of movement through simple ingress and egress from a parallel parking space onto a roadway (as opposed to ingress into and egress from a parking facility that is controlled and requires some type payment prior to leaving). The greatest difficulty such street parking alternatives pose is the typical requirement for a driver to make numerous passes along certain streets to search for a any vacant space, let alone one that is of proper size to allow for such a driver to undertake a parallel parking operation without contacting adjacent vehicles, as well as to allow for sufficient space to facilitate subsequent egress from the target space. As an alternative to controlled parking facilities and areas, then, although street parking may be desirable to drivers, the inherent problems with such an unreliable possibility has made such a parking alternative not only difficult to manage, but also potentially dangerous as drivers take too many chances due to time constraints and/or impatience.
There are actually two different systems provided by municipalities with regard to street parking arrangements: marked spaces and unmarked spaces. Marked configurations provide separated and properly delineated locations for drivers to choose in comparison with unmarked types, for obvious reasons. Such marked spaces inherently provide not only set distances, locations, and metering possibilities for such municipal entities, but also, to the contrary, inefficient overall space usage and limited revenue generation as a result. San Francisco has begun a pilot program utilizing a sensor system to provide notifications to drivers of empty marked spaces as well as a relatively straightforward manner of implementing charging methods to generate revenue directly in relation to marked space usage. Such an overall system, however, is relatively straightforward itself in that notification of such available marked spaces is much easier through specific sensor utilization. As well, correlating such sensor technology to a metering system that permits indications of parking initiation and ultimately parking space evacuation merely requires indications of sensor operation in the limited areas of such marked locations. In other words, the implementation of a notification/metering system limited to specific delineated parking spaces involves mere sensor activation and deactivation specifically for the sensors present within the area related directly to the marked spaces themselves. Unfortunately, as alluded to above, such marked space usage is rather inefficient, particularly in terms of allowing for various vehicle sizes (i.e., compact vehicles may fit easily within a space whereas a moving van will require far more space, and thus, in certain municipalities may not be permitted to park on a street). The capability of avoiding such inefficiencies with available on-street parking spaces while also according a reliable method of notifying drivers of vacant space of suitable size for specific types of vehicles would not only allow for reduction of necessary paint or other indication materials for marked spaces, but also would permit more efficient space usage and, overall, a reduction in pollution through allowing drivers a more direct route to a possible parking space. Additionally, the capability of implementing a suitable metering and charging method in relation to such an unmarked parking space system would allow, ultimately, to effective and more efficient revenue generation as the amount of available parking spaces would be increased through the omission of demarcations. To date, however, such has not been accorded by the on-street parking industry.
Controlled parking environments (such as lots and garages at public events, airports, stadiums, commuter lots, office buildings or other large parking areas) have been developed with certain marked space notifications in the past, although even these methods have proven problematic and time-consuming to a certain degree due to the difficulties in identifying available parking space locations, particularly in lots that are partially filled or almost filled to capacity. Such parking facilities, however, have, at least in some circumstances, been outfitted with either manual counting means or sensor devices to provide indications to drivers in various ways as to vacant spaces, both in terms of number and, at times, locations. Such notification operations, however, are limited in their scope to such location and number issues; since each parking space present within the confines of outfitted parking facilities are pre-sized and provided specifically for vehicles of various sizes, and, as such, the facilities themselves are configured to compensate for specific numbers of spaces properly aligned for such vehicles to park appropriately in side-by-side relation (and to allow ingress and egress from such spaces easily as result), such monitoring and consequent notification of availability and location is relatively simple and straightforward. Likewise, there is no need nor concern with providing any notification basis with regard to parking availability for vehicles that are parked end-to-end instead in such situations as the overall lot design generally includes such side-by-side arrangements (with limited possibilities of different space sizes based on the potential for smaller or larger vehicles that may be present). In any event, these prior parking lot notification schemes have basically pertained to set parking designations with specific parking configurations that are relatively easy to monitor as to vacancies and locations as a result. To the contrary, street parking, particularly such parking omitting any space demarcations, is highly erratic in principle since end-to-end, parallel parking requirements depend almost entirely on varied vehicle lengths and proper placement of such vehicles without any set configurations in place. Marked on-street parking spaces at least provide specific locations for drivers to select; again, though, such marked spaces are rather inefficient through limiting the amount of available spaces to too great a degree. For instance, with a standard block in New York City is ⅛th of a mile, or 660 feet in length. With set spaces of 23 feet (with one foot between each marked space), roughly 27 standard vehicles may be parked (theoretically, as driveways, hydrants, and set distances from intersections would invariably limit such numbers to a smaller number, in actuality). The utilization of unmarked systems would thus increase the amount of available space by at least six (20 feet per vehicle instead of set 24 feet distances). Additionally, and as noted above, set limits of 23 feet (with another foot set between each space) would consequently limit the type of vehicle that may actual park within such set spaces. Unlined spaces would thus allow, again, for all types and sizes of vehicles to utilize such on-street possibilities. As such, a greater efficiency for on-street parking would be realized if marked spaces were not implemented for these reasons.
Even with unrestrained on-street parking being the norm, other considerations may impact the overall capability of such a system. For instance, numerous items that prevent certain parking locations (such as fire hydrants, driveways, and the like) exist that may cause difficulties for a driver to properly find and select a parking spot. Additionally, the chaotic state of filling up limited spaces in end-to-end arrangements, particularly with, again, myriad lengths of vehicles (from small sub-compact vehicles to large trucks, vans, and/or buses, for example) makes predictability for a driver as to the proper space size for his or her vehicle rather daunting, beyond the initial consideration of whether any space is available to being with. In other words, in comparison with set parking lot configurations, the availability of spaces present on city streets is, suffice it to say, a difficult issue for a driver to overcome, particularly in terms of finding a suitable (and legal) space in a desirable location. In those situations, the longer a driver continues to seek for an available on-street parking space, the more fuel is consumed, the greater pollution is generated, and the more time lost for the driver in terms of his or her own efficiencies. With large numbers of vehicles searching for open spaces on a daily basis, the greater the accumulative effect such fuel consumption, undesirable exhaust, and lost time issues create.
Additionally, in terms of street parking issues, notifications are not easy to provide beyond the fact that end-to-end parking presents an extremely difficult prediction capability (due to the fact that vehicles do not have static lengths, not to mention the fact that other obstacles, such as fire hydrants, etc., may be present, as noted above) and the manner of providing such notifications, if they are provided in that context, would not be provided through, for example, typical board displays or other types of updated signage in a set location (such as is generally employed within parking facilities). The breadth of the street parking area in question would be too great to permit such a display to have any effect, basically, as the entirety of the area at issue would require street-by-street notifications to drivers in order to provide up-to-date and reliable information. As it is, a single, or perhaps two, three, or four, signs strategically placed in the multi-street area in question would require a driver to pass by, read, and comprehend the information provided in order to allow for such an on-street notification system to be effective. In essence, although street by street notifications may be effective in on-street parking configurations, the same has not been found true for typical signage utilized for parking lot situations.
As well, street metering requires investment in technology that requires expenditures for purchase, implementation, upkeep, and constant monitoring to be effective. As a revenue stream, such a system is rather straightforward (as discussed above) for set parking spaces (and thus set sensors with specific activation and deactivation sequences in relation to the presence of a vehicle in the target space). For unmarked spaces, to the contrary, such a needed overall system is, for lack of a better word, nonexistent. Without set spaces, it is difficult to have metering devices devoted to specific spaces (not to mention, individual meters are rather expensive to implement, operate, and monitor). Even with meters with marked spaces, such systems are rather cumbersome and unreliable (drivers do not always pay into the device, and thus an attendant must constantly monitor such areas for proper utilization; furthermore, limited time periods available to a driver for coin or other currency input would require repeated visits to the parking location to avoid incurring parking violations) and, as discussed at great length, inefficient in terms of available spaces and thus overall available numbers of vehicles that may be present within such spaces at any one time; optimizing and maximizing space availability and correlating such to revenue generating capacity would be far more attractive, for obvious reasons. Unfortunately, the capability of effectively charging drivers for unmarked street parking is limited to honor systems (for instance, requiring drivers to pay into permanent structures located on the street itself, and receiving a dashboard ticket for display during parking) as well as constant monitoring to ensure payment has been made for such a benefit. Avoidance of such cumbersome and relatively expensive requirements, in addition to the ability to provide effective and reliable notification to drivers of available and suitably sized spaces within an unmarked on-street parking configuration, has simply not been a possibility.
Of additional importance is the ability to accord drivers of large trucks (18-wheelers, for example) reliable indications as to the availability of locations to rest during a long trip. Federal regulations require such drivers to keep specific logs as to the length of delivery trips as well as the actual time spent driving on a specific day in order to best ensure such driving activities are as safe as possible. To that end, truck drivers utilize any available location to pull over and rest if and when such is necessary during a long trip. Thus, as has been recognizable on interstate highways, it is common for multiple trucks to park end-to-end at highway entry ramps and exit ramps, sometimes in rather long lines. Even, however, if such parking configurations are commonplace, truck drivers have been known to park in isolation in such locations in order to get the necessary rest for a long journey, placing themselves in potential jeopardy of being hit by vehicles or even of invasions by criminals while they are asleep. Certain refilling stations offer amenities to truck drivers (showers, sleeping berths, etc.), as well, although such activities cost money to the user, and prior notifications of availability.
Interstate (and other roadway) rest areas include segregated areas, generally, for such large vehicles to park, ostensibly to permit sufficient space dedicated for such a purpose. Within such highway arrangements, such rest areas are typically spaced from 50-80 miles apart, on average, thereby according such drivers the potential to properly time when they choose to stop. Unfortunately, however, the spaces available in such rest areas are limited and other than word-of-mouth from other drivers, there is little notification provided in terms of such parking space availability. As a result, this lack of notification (or parking availability guarantees) leaves such drivers at the mercy of chance in such situations; when they arrive, only then they can assess the parking space potential for a lengthy rest at a specific site. Additionally, however, it is not unheard of that smaller trucks (such as moving vans, for instance) may be parked in 18-wheeler designed (and typically dedicated) spaces, even though such vehicles may be better suited for the car/van locations at such rest areas. Again, this potential for loss of proper space for a large truck creates other scenarios that may exacerbate an already stressful driving experience.
Thus, there exists a need to provide not only on-street parking notifications as noted above, but also real-time parking space availability notifications for such large 18-wheel vehicles within rest area or other like locations with dedicated sites for such purposes. Furthermore, the ability to not only provide such availability indications but to monitor for vehicle sizes (to ensure proper utilization of such spaces for such specifically sized vehicles) as well as means to monitor the actual time spent within such spaces would be of enormous benefit for a variety of reasons within the driving industry. Additionally, the ability to provide a reservation service for drivers at specific locations would be extremely helpful, particularly to permit reliable timing for drivers to assess and undertake their required rest periods. To date, however, such a system has yet to be provided.


1. Field of the Invention
The present invention relates to methods for preparing 4-aminodiphenylamine (4-ADPA) and, more particularly, relates to a method for preparing 4-ADPA wherein aniline is reacted with nitrobenzene in the presence of a base, and under conditions wherein the amount of protic material, e.g., water, is controlled, to produce a mixture rich in the salt of 4-nitrodiphenylamine and/or the salt of 4-nitrosodiphenylamine. The 4-nitrodiphenylamine and/or 4-nitrosodiphenylamine salts can be isolated and subsequently hydrogenated or, alternatively, the reaction mixture itself is hydrogenated, to produce 4-ADPA in high yield. The present invention also relates to methods for preparing 4-ADPA intermediates as well as to alkylated p-phenylenediamine products useful as antioxidants.
2. Related Art
It is known to prepare 4-ADPA by way of a nucleophilic aromatic substitution mechanism, wherein an aniline derivative replaces halide. This method involves preparation of a 4-ADPA intermediate, namely 4-nitrodiphenylamine (4-NDPA) followed by reduction of the nitro moiety. The 4-NDPA is prepared by reacting p-chloronitrobenzene with an aniline derivative, such as formanilide or an alkali metal salt thereof, in the presence of an acid acceptor or neutralizing agent, such as potassium carbonate, and, optionally, utilizing a catalyst. See, for example, U.S. Pat. Nos. 4,187,248; 4,683,332; 4,155,936; 4,670,595; 4,122,118; 4,614,817; 4,209,463; 4,196,146; 4,187,249; 4,140,716. This method is disadvantageous in that the halide that is displaced is corrosive to the reactors and appears in the waste stream and must therefore be disposed of at considerable expense. Furthermore, use of an aniline derivative such as formanilide, and use of p-chloro-nitrobenzene, requires additional manufacturing equipment and capabilities to produce such starting materials from aniline and nitrobenzene, respectively.
It is also known to prepare 4-ADPA from the head-to-tail coupling of aniline. See, for example, G.B. 1,440,767 and U.S. Pat. No. 4,760,186. This method is disadvantageous in that the yield of 4-ADPA is not acceptable for a commercial process. It is also known to decarboxylate a urethane to produce 4-NDPA. See U.S. Pat. No. 3,847,990. However, such method is not commercially practical in terms of cost and yield.
It is known to prepare 4-ADPA by hydrogenating p-nitrosodiphenylhydroxylamine which can be prepared by catalytic dimerization of nitrosobenzene utilizing, as a reducing agent, aliphatic compounds, benzene, naphthalene or ethylenically unsaturated compounds. See, for example, U.S. Pat. Nos. 4,178,315 and 4,404,401. It is also known to prepare p-nitrosodiphenylamine from diphenylamine and an alkyl nitrate in the presence of excess hydrogen chloride. See, for example, U.S. Pat. Nos. 4,518,803 and 4,479,008.
It is also known to produce 4-nitrosodiphenylamine by reacting acetanilide and nitrobenzene in DMSO in the presence of sodium hydroxide and potassium carbonate at 80.degree. C. for 5 hours. See Ayyangar et al., Tetrahedron Letters, Vol. 31, No. 22, pp. 3217-3220 (1990). See also, Wohl, Chemische Berichte, 36, p. 4135 (1903) and Chemische Berichte, 34, p. 2442 (1901). However, the yield of 4-nitrosodiphenylamine is low and is therefore not commercially practical. Furthermore, such method requires utilization of an aniline derivative, namely, acetanilide, and therefore increases the cost of the starting materials.
The process of the present invention does not include a halide source and therefore eliminates the expensive halide removal from the waste stream. In addition, the process of the present invention is much less expensive in terms of manufacturing costs, as well as the cost of raw materials, because instead of the derivatives of aniline and nitrobenzene, the present method utilizes aniline and nitrobenzene directly.


1. Field of the Invention
The present invention relates to an information processing device, an information processing method, and a program. More specifically, the present invention relates to an information processing device, an information processing method, and a program to control display of information depending on a mode in which the device is used, in relation to the information processing device combining an image display function and a printing function.
2. Description of the Related Art
There has been widely used a digital photo frame as a photo frame type of a display device for displaying, for example, pictures taken with a digital camera. The digital photo frame, for example, is loaded with a recording medium such as a flash memory that stores an image taken with the digital camera, and displays the image stored in the medium on a display unit including a liquid crystal display (LCD) or the like. A user can use the digital photo frame as a photo frame by selecting a favorite picture from among a large volume of image data stored in the medium and displaying it on the display unit. Such a photo frame is described in, for example, Japanese Unexamined Patent Application Publication No. 2009-45139.
There is also a device configured to be connected to a printer via a universal serial bus (USB) terminal and a USB cable and output the image displayed on the display unit to the printer. Such a device with a printing function receives various settings for printing, command inputs, and the like through a remote control, a touch screen, or an operation switch or an operation button arranged in a space around the display unit.
For use as a photo frame, however, the switch or the button for printing presented on or around the display unit spoils a view disadvantageously causing disfigurement and lowering quality. Even if the operation button for printing can be provided on the back of the display unit, such a configuration is disadvantageous because it is difficult to operate the button when the user wants to print out the image while viewing the image displayed on the display unit.


1. Field of the Invention
This invention relates to methods and apparatus for processing and cleaning a substrate, and more specifically to methods and apparatus for cleaning semiconductor substrates after polishing of copper films.
2. Background Information
In the manufacture of advanced semiconductor devices, copper (Cu) is beginning to replace aluminum (Al) as the material for metallization. Cu has become desirable due to its lower resistivity and significantly improved electromigration lifetime, when compared to Al.
One process for Cu metallization uses a dual damascene approach. As illustrated in FIG. 1a, a dielectric layer 110 is deposited above a substrate 100. Dielectric layer 110 may be made up of materials such as silicon dioxide. Vias and/or trenches 120 are then formed in the dielectric layer 110, as illustrated in FIG. 1b. Vias/trenches 120 may be formed, for example, using dry etching techniques. Next, a thin layer of barrier material (barrier layer) 130, for example, tantalum (Ta), titanium (Ti), or titanium nitride (TiN) is deposited as illustrated in FIG. 1c. After barrier layer 130 is deposited the vias/trenches 120 are filled with copper (Cu) layer 140, as illustrated in FIG. 1d. Copper layer 140 may be deposited using well known deposition techniques such as, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), or electroplating. In order to isolate the copper interconnects, as illustrated in FIG. 1e, the excess copper layer 140 and barrier layer 130 must be removed.
One method for removing the excess copper layer 140 and barrier layer 130 is polishing the surface of the substrate, for example, polishing using chemical mechanical polishing (CMP). In a CMP process, the semiconductor substrate is polished with a slurry containing abrasive particles, such as alumina particles, and an oxidant, such as hydrogen peroxide. In the CMP process, contaminants are introduced which include particles and/or metal contamination on the copper layer 150, dielectric surface 160, and in the dielectric subsurface 165.
Regardless of how the CMP process is performed, the surface of semiconductor substrate must be cleaned of contaminants. If not removed, these contaminants may affect device performance characteristics and may cause device failure to occur at faster rates than usual. Cleaning the semiconductor substrate after chemical mechanical polishing of copper may be necessary to remove such contaminants from the copper layer and dielectric layers.
One method for cleaning the semiconductor substrate after polishing of the copper layer is brush scrubbing. Brush scrubbing, whether single-sided or double-sided brush scrubbing, is the industry standard for cleaning oxide and tungsten CMP applications. However, there are several problems associated with applying brush scrubbing to post copper CMP cleaning.
One such problem is brush loading. During the CMP process, the top surface of the copper layer may be oxidized and forms copper oxide, for example copper oxide (Cu.sub.2 O or CuO) or copper hydroxide (Cu(OH).sub.2). In basic or neutral pH cleaning environments, the copper oxide or copper hydroxide does not dissolve and may be transferred to the brushes, thus loading the brushes. The contaminated (or loaded) brushes may then transfer the copper oxide or copper hydroxide contaminants to subsequently processed substrates during cleaning.
For tungsten and other oxide applications, brush loading could be curtailed by adding a dilute ammonium hydroxide (NH.sub.4 OH). In the presence of NH.sub.4 OH, part of the copper oxide may form Cu(NH.sub.3).sup.2+ complex and may be dissolved; however, due to the high pH environment, the dilute ammonium hydroxide has been found to be insufficient to prevent brush loading of copper oxide. Additionally, it has been found that scrubbing with dilute ammonium hydroxide also causes etching of the copper layer and may cause serious surface roughening.
Brush loading may also occur when alumina particles are used in the copper CMP process. In neutral or inorganic acid (e.g. HCl) cleaning environments, there is an electrostatic attraction between alumina particles and the silicon dioxide surface which makes it difficult to remove the alumina particles from the surface of the dielectric material. Because of the electrostatic attractive force, the alumina particles may also adhere to the brush and cause another brush loading problem with similar effects to those discussed above.
Yet another problem caused by the CMP process is that the surface and subsurface of the dielectric layer may become contaminated during polishing with metal from the copper layer and barrier layer as well as other contaminants from the slurry. During the CMP process, contaminants, especially metal contaminants, may penetrate into the dielectric layer up to approximately 100 angstroms (.ANG.) from the surface. Again, these contaminants may affect device performance characteristics and may cause device failure.
Thus, what is needed is a cleaning environment and methods for cleaning post copper CMP substrates that alleviate the problems of brush loading without affecting the quality of the copper and dielectric layers. Furthermore, what is needed is a cleaning environment and methods for cleaning post copper CMP substrates that have the capability of removing surface and subsurface contaminants from the copper and dielectric layers.


Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for controlling an uplink power in a wireless communication system.
Related Art
Universal mobile telecommunications system (UMTS) is a 3rd generation (3G) asynchronous mobile communication system operating in wideband code division multiple access (WCDMA) based on European systems, global system for mobile communications (GSM) and general packet radio services (GPRS). A long-term evolution (LTE) of UMTS is under discussion by the 3rd generation partnership project (3GPP) that standardized UMTS.
The 3GPP LTE is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
To increase the capacity for the users' demand of services, increasing the bandwidth may be essential, a carrier aggregation (CA) technology or resource aggregation over intra-node carriers or inter-node carriers aiming at obtaining an effect, as if a logically wider band is used, by grouping a plurality of physically non-continuous bands in a frequency domain has been developed to effectively use fragmented small bands. Individual unit carriers grouped by carrier aggregation is known as a component carrier (CC). For inter-node resource aggregation, for each node, carrier group (CG) can be established here one CG can have multiple CCs. Each CC is defined by a single bandwidth and a center frequency.
In LTE Rel-12, a new study on small cell enhancement has started, where dual connectivity is supported. Dual connectivity is an operation where a given UE consumes radio resources provided by at least two different network points (master eNB (MeNB) and secondary eNB (SeNB)) connected with non-ideal backhaul while in RRC_CONNECTED. Furthermore, each eNB involved in dual connectivity for a UE may assume different roles. Those roles do not necessarily depend on the eNB's power class and can vary among UEs.
Uplink power control determines the average power over a single carrier frequency division multiple access (SC-FDMA) symbol in which the physical channel is transmitted. Uplink power control controls the transmit power of the different uplink physical channels. Efficient uplink power control method for CA or dual connectivity may be required.


Computing devices generally operate using a combination of firmware and software that is configured to execute on the hardware of a given computing device. A given set of firmware and software (e.g., the operating system) that is used to operate a computing device may be referred to as an operating image for the computing device.
A computing device may come with a trusted operating image (e.g., an image that is signed and may be verified with a key) that was installed onto the computing device in the factory or updated using a trusted image source. However, computing device users may also wish to load and boot images that are not verified or not trusted (e.g., unsigned or self-signed images). For example, a user may wish to customize and make changes to the operating system for the computing device or the user may wish to install a different operating system in addition to or to replace the existing operating system.


1. Field of the Invention
The present invention relates in general to computing systems, and more particularly, to systems and methods for background destaging storage tracks from cache when one or more hosts coupled to the cache are idle.
2. Description of the Related Art
One goal of computer storage systems is to reduce the number of destage conflicts when destaging storage tracks from a write cache so that the storage system operates more efficiently and/or faster. A destage conflict can occur when a storage track is being destaged from the write cache while a host is trying to write data to the storage track. This situation may be created because contemporary storage systems typically destage storage tracks shortly after the storage track is written to and the host must wait until the storage track is destaged from the write cache before the host is able to again write to the storage track. One technique to reduce the number of destage conflicts includes keeping storage tracks in the write cache for a longer period of time before destaging the storage tracks so that a storage track may be written to multiple times before the storage track is destaged. While this is an effective technique for reducing destage conflicts, it is also desirable that storage tracks not reside in the write cache too long so that the data in the storage tracks does not become stale.


Controlled sharing of objects is fundamental to distributed systems. However, only limited and simple means of sharing are supported in network or cloud-based systems. Current software systems are often constructed as a decentralized graph of collaborative, loosely-coupled services that include different protection domains, communication channels, execution environments and implementations.
As such, security and access control are of concern. Instead of using public-key based certificates or other sophisticated key agreement, cloud-based services typically use a pattern of pure bearer tokens or authentication credentials. Bearer tokens or credentials that grant unconditional authority are often sent directly between clients, servers and protection domains, even on unencrypted channels.


It is known for a rocket engine to include as a component thereof a thrust chamber having several sections joined to each other in an axial direction. Each of the sections is formed by a wall structure having an inner wall, an outer wall parallel thereto, and cooling channels formed between the inner and outer walls. The wall structure is continuous in the circumferential direction of the section.
The inner wall of each of two joined (to be joined) sections projects further (longer) in the extension direction of the wall structure than does the outer wall. The projecting end portion of the inner wall of one section is joined to the adjacent projecting end portion of the inner wall of the other section by a weld joint. In this way, a substantially continuous inner wall is achieved.
Thereafter, a ring-shaped element is radially arranged outside the weld joint, and said element is joined to the end portions of the adjacent outer walls. In this way, the cooling channels of one of the sections can communicate with the cooling channels of the adjacent section.
Even though the above described rocket engine component performs satisfactorily, there is still a desire to increase the life of the component so that it can be used for an increased number of engine cycles.


Insect pests are a serious problem in agriculture. They destroy millions of acres of staple crops such as corn, soybeans, peas, and cotton. Yearly, these pests cause over $100 billion dollars in crop damage in the U.S. alone. In an ongoing seasonal battle, farmers must apply billions of gallons of synthetic pesticides to combat these pests. However, synthetic pesticides pose many problems. They are expensive, costing U.S. farmers almost $8 billion dollars per year. They force the emergence of insecticide-resistant pests, and they can harm the environment.
Other approaches to pest control have been tried. In some cases, crop growers have introduced “natural predators” of the species sought to be controlled such as non-native insects, fungi, and bacteria like Bacillus thuringiensis. Alternatively, crop growers have introduced large colonies of sterile insect pests in the hope that mating between the sterilized insects and fecund wild insects would decrease the insect population. Unfortunately, success has been equivocal and the expense considerable. For example, as a practical matter, introduced species rarely remain on the treated land—spreading to other areas as an unintended consequence. Predator insects migrate, and fungi or bacteria wash off of plants into streams and rivers. Consequently, crop growers need more practical and effective solutions.
One relatively recent solution has been to genetically engineer crops to express plant lipases that have insecticidal properties. Until now, such insecticidal lipases have only been described in certain plants, such as patatin from the potato (U.S. Pat. No. 5,743,477) and pentin from the oil bean tree (U.S. Pat. Nos. 6,057,491 and 6,339,144). However, plant-derived lipases have the inherent disadvantage of having induced natural selection pressure in insects feeding on these plants in the wild. Thus, alternative lipases are needed for insect resistance management. The present invention is useful for avoiding the inherent disadvantage of pre-existing natural selection pressure, while conferring numerous other advantages such as low cost relative to repeated-application pesticides and effective insecticidal properties.