A process for the preparation of titanyl phthalocyanine Type 1a which comprises admixing Type I titanyl phthalocyanine with a component that enables dissolution thereof; adding the resulting dissolved titanyl phthalocyanine pigment to a solvent mixture thereby enabling reprecipitation of said pigment; and subsequently contacting the Type X titanyl phthalocyanine formed with hot halobenzene.

This invention is generally directed to titanyl phthalocyanines, imaging members and processes for the preparation thereof, and more specifically the present invention is directed to processes for obtaining titanyl phthalocyanine Type 1a polymorph and layered photoconductive members comprised of the aforementioned titanyl phthalocyanine polymorph. In embodiments, the present invention is directed to imaging members containing as a photogenerating pigment titanyl phthalocyanine Type 1a prepared by a two step direct process which comprises treating Type X titanyl phthalocyanine with a halobenzene, such as heated chlorobenzene or chloronaphthalene. The titanyl phthalocyanine Type 1a can be selected as an organic photogenerator pigment in photoresponsive imaging members containing charge transport components, especially hole transport layers such as known aryl amine hole transport molecules. The aforementioned photoresponsive imaging members can be negatively charged when the photogenerating layer is situated between the hole transport layer and the substrate, or positively charged when the hole transport layer is situated between the photogenerating layer and the supporting substrate. The layered photoconductive imaging members can be selected for a number of different known imaging and printing processes including, for example, electrophotographic imaging processes, especially xerographic imaging and printing processes wherein negatively charged or positively charged images are rendered visible with toner compositions of the appropriate charge. Generally, the imaging members are sensitive in the wavelength regions of from about 700 to about 800 nanometers, thus diode lasers can be selected as the light source.
Certain titanium phthalocyanine pigments have been known, reference the publication WW 2 (PB 85172 Fiat Final Report 1313, Feb. 1, 1948). Specific titanyl phthalocyanines or oxytitanium phthalocyanines are known to absorb near-infrared light at about 800 nanometers and a number of such pigments have been illustrated in the prior art as materials for IR laser optical recording material, reference for example BASF German 3,643,770 and U.S. Pat. No. 4,458,004. The use of certain titanium phthalocyanine pigments as a photoconductive material for electrophotographic applications is known, reference for example British Patent Publication 1,152,655, the disclosure of which is totally incorporated herein by reference. Also, U.S. Pat. No. 3,825,422 illustrates the use of titanyl phthalocyanine as a photoconductive pigment in an electrophotographic process known as particle electrophoresis. Additionally, the utilization of certain titanyl phthalocyanines and substituted derivatives thereof in a dual layer electrographic device is illustrated in EPO 180931, May 14, 1986. Moreover, the use of tetra- and hexadeca-flouro-substituted titanyl phthalocyanine in an electrophotographic device is illustrated in U.S. Pat. No. 4,701,396. In Japanese Patent Publication 64-171771, August, 1986, there is illustrated the use of titanyl phthalocyanine, which has been treated with a hot solvent, in electrophotography. Further, in German 3,821,628 there is illustrated the utilization of certain titanyl phthalocyanines, and other pigments in electrophotography, and wherein the titanyl phthalocyanines have been purified primarily to reduce the level of ash, volatile contaminants and sodium to below specified levels.
In the textbook Phthalocyanine Compounds by Moser and Thomas, the disclosure of which is totally incorporated herein by reference, it is indicated that polymorphism or the ability to form distinct solid state forms is well known in phthalocyanines. For example, metal-free phthalocyanine is known to exist in at least 5 forms designated as alpha, beta, pi, X and tau. Copper phthalocyanine crystal forms known as alpha, beta, gamma, delta, epsilon and pi are also described. These different polymorphic forms are usually distinguishable on the basis of differences in the solid state properties of the materials which can be determined by measurements, such as Differential Scanning Calorimetry, Infrared Spectroscopy, Ultraviolet-Visible-Near Infrared spectroscopy and, especially, X-Ray Powder Diffraction techniques. There appears to be general agreement on the nomenclature used to designate specific polymorphs of commonly used pigments such as metal-free and copper phthalocyanine. However, this does not appear to be the situation with titanyl phthalocyanines as different nomenclature is selected in a number of instances.
The X-ray powder diffraction traces (XRPDs) obtained from 5 forms of titanyl phthalocyanine are illustrated in U.S. Pat. No. 5,166,339 (D/90198), the disclosure of which is totally incorporated herein by reference and which were generated on a Philips X-Ray Powder Diffractometer Model 1710 using X-radiation of CuK.alpha. wavelength (.lambda.=0.1542 nanometers). The diffractometer was equipped with a graphite monochrometer and pulse-height discrimination system. Two-theta is the Bragg angle commonly referred to in x-ray crystallographic measurements. I(counts) represents the intensity of the diffraction as a function of Bragg angle as measured with a proportional counter. Subclasses of these forms with broad, more poorly resolved peaks than those shown in FIGS. 1A, 1B, 1C, 1D and 1E can be envisioned, however, the basic features of the diffractograms indicate the major peaks in the same position, although the smaller peaks can be unresolved. This broadening of XRPD peaks is generally found in pigments having a very small particle size. In Table 1 that follows, there is provided a listing of documents that disclose titanyl phthalocyanine polymorpic forms classified as belonging to one of the main types as indicated.
TABLE 1 ______________________________________ Crystal Other Form Names Documents ______________________________________ Type I .beta. Toyo Ink Electrophotog. (Japan) 27,533 (1988) .beta. Dainippon U.S. Pat. No. 4,728,592 .beta. Sanyo-Shikiso JOP 63-20365 A Mitsubishi JOP 62-25685, -6, -7 Conference Proceedings A Konica "Japan Hardcopy", 1989, 103, (1989) Type II .alpha. Toyo Ink "Electrophoto (Japan)" 27,533 (1988) .alpha. Sanyo-Shikiso JOP 63-20365 .alpha. Konica U.S. Pat. No. 4,898,799 .alpha. Dainippon U.S. Pat. No. 4,728,592 .alpha. Mita EU 314,100 B Mitsubishi JOP 62-25685, -6, -7 B Konica "Japan Hardcopy", 1989, 103, (1989) Type III C Mitsubishi OP 62-25685, -6, -7 C Konica "Japan Hardcopy", 1989, 103, (1989) m Toyo Ink "Electrophoto (Japan)" 27,533 (1988) Type IV y Konica "Japan Hardcopy", 1989, 103, (1989) Unnamed Konica U.S. Pat. No. 4,898,799 New Sanyo-Shikiso JOP 63-20365 Type ______________________________________
More specifically, the aforementioned documents illustrate, for example, the use of specific polymorphs of TiOPc in electrophotographic devices. Three crystal forms of titanyl phthalocyanine, differentiated by their XRPDs, were specifically illustrated, identified as A, B, and C, which it is believed are equivalent to Types I, II, and III, respectively. In Japanese 62-256865 there is disclosed, for example, a process for the preparation of pure Type I involving the addition of titanium tetrachloride to a solution of phthalonitrile in an organic solvent which has been heated in advance to a temperature of from 160.degree. to 300.degree. C. In Japanese 62-256866, there is illustrated, for example, a method of preparing the aforementioned polymorph which involves the rapid heating of a mixture of phthalonitrile and titanium tetrachloride in an organic solvent at a temperature of from 100.degree. to 170.degree. C. over a time period which does not exceed one hour. In Japanese 62-256867, there is described, for example, a process for the preparation of pure Type II (B) titanyl phthalocyanine, which involves a similar method except that the time to heat the mixture at from 100.degree. to 170.degree. C. is maintained for at least two and one half hours. Types I and II, in the pure form obtained by the process of the above publications, apparently afforded layered photoresponsive imaging members with excellent electrophotographic characteristics.
In Mita EPO Patent Publication 314,100, there is illustrated the synthesis of TiOPc by, for example, the reaction of titanium alkoxides and diiminoisoindolene in quinoline or an alkylbenzene, and the subsequent conversion thereof to an alpha type pigment (Type II) by an acid pasting process, whereby the synthesized pigment is dissolved in concentrated sulfuric acid, and the resultant solution is poured onto ice to precipitate the alpha-form, which is filtered and washed with methylene chloride. This pigment, which was blended with varying amounts of metal free phthalocyanine, could be selected as the charge generating layer in layered photoresponsive imaging members with a high photosensitivity at, for example, 780 nanometers.
In Sanyo-Shikiso Japanese 63-20365/86, reference is made to the known crystal forms alpha and beta TiOPc (Types II and I, respectively, it is believed), which publication also describes a process for the preparation of a new form of titanyl phthalocyanine, which is apparently not named. This publication appears to suggest the use of the unnamed titanyl phthalocyanine as a pigment and its use as a recording medium for optical discs. This apparently new form was prepared by treating acid pasted TiOPc (Type II form, it is believed) with a mixture of chlorobenzene and water at about 50.degree. C. The resulting apparently new form is distinguished on the basis of its XRPD, which appears to be identical to that shown in FIG. 1 for the Type IV polymorph.
In U.S. Pat. No. 4,728,592, there is illustrated, for example, the use of alpha type TiOPc (Type II) in an electrophotographic device having sensitivity over a broad wavelength range of from 500 to 900 nanometers. This form was prepared by the treatment of dichlorotitanium phthalocyanine with concentrated aqueous ammonia and pyridine at reflux for 1 hour. Also described in the aforementioned patent is a beta type TiOPc (Type I) as a pigment, which is believed to provide a much poorer quality photoreceptor.
In Konica Japanese 64-17066/89, there is disclosed, for example, the use of a new crystal modification of TiOPc prepared from alpha type pigment (Type II) by milling it in a sand mill with salt and polyethylene glycol. This pigment had a strong XRPD peak at a value of 2 theta of 27.3 degrees. This publication also discloses that this new form differs from alpha type pigment (Type II) in its light absorption and shows a maximum absorbance at 817 nanometers compared to the alpha-type, which has a maximum at 830 nanometers. The XRPD shown in the publication for this new form is believed to be identical to that of the Type IV form previously described by Sanyo-Shikiso in JOP 63-20365. The aforementioned Konica publication also discloses the use of this new form of TiOPc in a layered electrophotographic device having high sensitivity to near infrared light of 780 nanometers. The new form is indicated to be superior in this publication to alpha type TiOPc (Type II). Further, this new form is also described in U.S. Pat. No. 4,898,799 and in a paper presented at the Annual Conference of Japan Hardcopy in July 1989. In this paper, this same new form is referred to as Type y, and reference is also made to Types I, II, and III as A, B, and C, respectively.
In the journal, Electrophotography (Japan), vol. 27, pages 533 to 538, Toyo Ink Manufacturing Company, there is disclosed, for example, alpha and beta forms of TiOPc (Types I and II, it is believed) and also this journal discloses the preparation of a Type m TiOPc, an apparently new form having an XRPD pattern which was distinct from other crystal forms. It is believed that this XRPD is similar to that for the Type III titanyl phthalocyanine pigment, but it is broadened most likely as the particle size is much smaller than that usually found in the Type III pigment. This pigment was used to prepare photoreceptor devices having greater sensitivity at 830 nanometers than alpha or beta type TiOPc (Type II or I, respectively).
In Mitsubishi Laid Open Japanese Application 90-269776, laid open date Nov. 5, 1990, the disclosure of which is totally incorporated herein by reference, there is illustrated the preparation of titanyl phthalocyanines by the treatment of phthalocyanines, such as metal free, metal phthalocyanines, or their derivatives with solvents containing at least trifluoroacetic acid, or mixed solvents of trifluoroacetic acid and halogenated hydrocarbons such as methylene chloride. In Example I of this Japanese Laid Open Application, the preparation of the C-form of TiOPc is described. Other forms obtained are described in Examples II and III.
Processes for the preparation of specific polymorphs of titanyl phthalocyanine, which require the use of a strong acid, such as sulfuric acid, are known, and these processes, it is believed, are not easily scalable. One process as illustrated in Konica Japanese Laid Open on Jan. 20, 1989 as 64-17066 (U.S. Pat. No. 4,643,770 appears to be its equivalent), the disclosures of which are totally incorporated herein by reference, involves, for example, the reaction of titanium tetrachloride and phthalodinitrile in 1-chloronaphthalene solvent to produce dichlorotitanium phthalocyanine which is then subjected to hydrolysis by ammonia water to enable the Type II polymorph. This phthalocyanine is preferably treated with an electron releasing solvent, such as 2-ethoxyethanol, dioxane, N-methylpyrrolidone, followed by subjecting the alpha-titanyl phthalocyanine to milling at a temperature of from 50.degree. to 180.degree. C. In a second method described in the aforementioned Japanese Publication, there is disclosed the preparation of alpha type titanyl phthalocyanine with sulfuric acid. Another method for the preparation of Type IV titanyl phthalocyanine involves the addition of an aromatic hydrocarbon solvent to an aqueous suspension of Type II titanyl phthalocyanine prepared by the well-known acid pasting process, and heating the resultant suspension to about 50.degree. C. as disclosed in Sanyo-Shikiso Japanese 63-20365, Laid Open on Jan. 28, 1988. In Japanese 171771/1986, Laid Open Aug. 2, 1986, there is disclosed the purification of metallophthalocyanine by treatment with N-methylpyrrolidone.
To obtain a TiOPc-based photoreceptor having high sensitivity to near infrared light, it is believed necessary to control not only the purity and chemical structure of the pigment, as is generally the situation with organic photoconductors, but also to prepare the pigment in the correct crystal modification. A number of the disclosed processes used to prepare specific crystal forms of TiOPc, such as Types I, II, III and IV, are either complicated and difficult to control as in the preparation of pure Types I and II pigment by the processes described in Mitsubishi Japanese 62-25685, -6 and -7; involve harsh treatment such as sand milling at high temperature, reference Konica U.S. Pat. No. 4,898,799; or dissolution of the pigment in a large volume of concentrated sulfuric acid, a solvent which is known to cause decomposition of metal phthalocyanines, reference Sanyo-Shikiso Japanese 63-20365, and Mita EPO 314, 100.
Generally, layered photoresponsive imaging members are described in a number of U.S. patents, such as U.S. Pat. No. 4,265,900, the disclosure of which is totally incorporated herein by reference, wherein there is illustrated an imaging member comprised of a photogenerating layer, and an aryl amine hole transport layer. Examples of photogenerating layer components include trigonal selenium, metal phthalocyanines, vanadyl phthalocyanines, and metal free phthalocyanines. Additionally, there is described in U.S. Pat. No. 3,121,006 a composite xerographic photoconductive member comprised of finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. The binder materials disclosed in the '006 patent comprise a material which is incapable of transporting for any significant distance injected charge carriers generated by the photoconductive particles.
The use of selected perylene pigments as photoconductive substances is also known. There is thus described in Hoechst European Patent Publication 0040402, DE3019326, filed May 21, 1980, the use of N,N'-disubstituted perylene-3,4,9,10-tetracarboxyldiimide pigments as photoconductive substances. Specifically, there is, for example, disclosed in this publication N,N'-bis(3-methoxypropyl)perylene-3,4,9,10-tetracarboxyldiimide dual layered negatively charged photoreceptors with improved spectral response in the wavelength region of 400 to 700 nanometers. A similar disclosure is revealed in Ernst Gunther Schlosser, Journal of Applied Photographic Engineering, Vol. 4, No. 3, page 118 (1978). There are also disclosed in U.S. Pat. No. 3,871,882 photoconductive substances comprised of specific perylene-3,4,9,10-tetracarboxylic acid derivative dyestuffs. In accordance with the teachings of this patent, the photoconductive layer is preferably formed by vapor depositing the dyestuff in a vacuum. Also, there are specifically disclosed in this patent dual layer photoreceptors with perylene-3,4,9,10-tetracarboxylic acid diimide derivatives, which have spectral response in the wavelength region of from 400 to 600 nanometers. Also, in U.S. Pat. No. 4,555,463, the disclosure of which is totally incorporated herein by reference, there is illustrated a layered imaging member with a chloroindium phthalocyanine photogenerating layer. In U.S. Pat. No. 4,587,189, the disclosure of which is totally incorporated herein by reference, there is illustrated a layered imaging member with a perylene pigment photogenerating component. Both of the aforementioned patents disclose an aryl amine component as a hole transport layer.
Moreover, there are disclosed in U.S. Pat. No. 4,419,427 electrographic recording mediums with a photosemiconductive double layer comprised of a first layer containing charge carrier perylene diimide dyes, and a second layer with one or more compounds which are charge transporting materials when exposed to light, reference the disclosure in column 2, beginning at line 20.
In copending application U.S. Ser. No. 537,714 (D/90087), the disclosure of which is totally incorporated herein by reference, there are illustrated photoresponsive imaging members with photogenerating titanyl phthalocyanine layers prepared by vacuum deposition. It is indicated in this copending application that the imaging members comprised of the vacuum deposited titanyl phthalocyanines and aryl amine hole transporting compounds exhibit superior xerographic performance as low dark decay characteristics result and higher photosensitivity is generated, particularly in comparison to several prior art imaging members prepared by solution coating or spray coating, reference for example, U.S. Pat. No. 4,429,029 mentioned hereinbefore.
In U.S. Pat. No. 5,153,313 (D/90244), the disclosure of which is totally incorporated herein by reference, there is illustrated a process for the preparation of phthalocyanine composites which comprises adding a metal free phthalocyanine, a metal phthalocyanine, a metalloxy phthalocyanine or mixtures thereof to a solution of trifluoroacetic acid and a monohaloalkane; adding to the resulting mixture a titanyl phthalocyanine; adding the resulting solution to a mixture that will enable precipitation of said composite; and recovering the phthalocyanine composite precipitated product.
In U.S. Pat. No. 5,166,339 (D/90198), the disclosure of which is totally incorporated herein by reference, there is illustrated a process for the preparation of titanyl phthalocyanine which comprises the reaction of titanium tetrapropoxide with diiminoisoindolene in N-methylpyrrolidone solvent to provide Type I, or .beta.-type titanyl phthalocyanine as determined by X-ray powder diffraction; dissolving the resulting titanyl phthalocyanine in a mixture of trifluoroacetic acid and methylene chloride; adding the resulting mixture to a stirred organic solvent, such as methanol, water, or mixtures thereof; separating the resulting precipitate by, for example, vacuum filtration through a glass fiber paper in a Buchner funnel; and washing the titanyl phthalocyanine product. Examples of titanyl phthalocyanine reactants that can be selected in effective amounts of, for example, from about 1 weight percent to about 40 percent by weight of the trifluoroacetic acidic solvent mixture include known available titanyl phthalocyanines; titanyl phthalocyanines synthesized from the reaction of titanium halides such as titanium trichloride, titanium tetrachloride or tetrabromide, titanium tetraalkoxides such as titanium tetra-methoxide, -ethoxide, -propoxide, -butoxide, -isopropoxide and the like; and other titanium salts with compounds such as phthalonitrile and diiminoisoindolene in solvents such as 1-chloronaphthalene, quinoline, N-methylpyrrolidone, and alkylbenzenes such as xylene at temperatures of from about 120.degree. to about 300.degree. C.; specific polymorphs of titanyl phthalocyanine such as Type I, II, III, and IV, the preparation of which, for example, is described in the literature; or any other suitable polymorphic form of TiOPc; substituted titanyl phthalocyanine pigments having from 1 to 16 substituents attached to the outer ring of the compound, said substituent being, for example, halogens such as chloro-, bromo-, iodo- and fluoro-, alkyls with from 1 to about 6 carbon atoms such as methyl-, ethyl-, propyl-, isopropyl-, butyl-, pentylo, and hexyl-; nitro, amino, alkoxy and alkylthio, such as methoxy-, ethoxy- and propylthio- groups; and mixtures thereof.
Disclosed in U.S. Pat. No. 5,164,493 (D/90524), the disclosure of which is totally incorporated herein by reference, is a process for the preparation of titanyl phthalocyanine Type I which comprises the addition in a solvent of titanium tetraalkoxide to a mixture of phthalonitrile and a diiminoisoindolene, followed by heating. The disclosure of this application is totally incorporated herein by reference.
Disclosed in U.S. Pat. No. 5,189,156 (D/91152), the disclosure of which is totally incorporated herein by reference, is a process for the preparation of titanyl phthalocyanine Type I which comprises the reaction of titanium tetraalkoxide and diiminoisoindolene in the presence of a halonaphthalene solvent; and U.S. Pat. No. 5,206,359 (D/91151), the disclosure of which is totally incorporated herein by reference, is a process for the preparation of titanyl phthalocyanine Type IV having outstanding electrophotographic properties, which comprises the treatment of titanyl phthalocyanine Type X with monochlorobenzene at room temperature to provide Type IV TiOPc.
Illustrated in copending patent application U.S. Ser. No. 024,145 (D/92270), the disclosure of which is totally incorporated herein by reference, is a process for the preparation of a more perfect crystalline form of the Type I polymorph of titanyl phthalocyanine which comprises dissolving a precursor titanyl phthalocyanine Type I in a solution of trihaloacetic acid and alkylene chloride; adding the resultant solution to a solvent thereby enabling precipitation of Type X titanyl phthalocyanine; separating the titanyl phthalocyanine Type X from the solution; followed by a first washing with an organic solvent and a second washing with water; slurrying the resulting Type X titanyl phthalocyanine in an organic solvent enabling conversion of said Type X to Type IV titanyl phthalocyanine; and thereafter, subjecting the Type IV titanyl phthalocyanine obtained to treatment with an organic solvent to enable said crystalline form of titanyl phthalocyanine Type I; and a process in accordance with claim 1 wherein said Type X polymorph is slurried at about 25.degree. C. in from about 10 volume parts to about 100 volume parts of chlorobenzene for a period of from about 1 minute to about 120 minutes.
Illustrated in U.S. Pat. No. 5,330,867 is a layered imaging member comprised of a photogenerating layer of titanyl phthalocyanine prepared by depositing amorphous titanyl phthalocyanine on a substrate maintained at a temperature of from below 25.degree. to about minus 30.degree. C.; and contacting the substrate product with an aliphatic alcohol; in U.S. Pat. No. 5,288,574 is a layered photoconductive imaging member comprised of a supporting substrate, a photogenerating layer comprised of titanyl phthalocyanine photogenerating pigments and thereover a charge transport layer, and wherein said photogenerating pigments are prepared by a process which comprises the formation of a slurry comprised of dihalotitanium phthalocyanine in a mixture comprised of a trihaloacetic acid and an alkylene chloride; adding the resultant slurry to a mixture of an aliphatic alcohol and water enabling hydrolysis whereby Type X oxytitanium phthalocyanine is obtained; separating the Type X oxytitanium phthalocyanine from the slurry; and thereafter subjecting the Type X oxytitanium phthalocyanine obtained to treatment with a halobenzene, followed by the separation of Type IV oxytitanium phthalocyanine photogenerating pigments; and in U.S. Pat. No. 5,334,478 is a layered photoconductive imaging member comprised of a supporting substrate, a photogenerating layer and a charge transport layer, and wherein the photogenerating layer contains Type IV titanyl phthalocyanine obtained by a process which comprises the addition of an oxytitanium phthalocyanine containing a mixture of Type I and Type II titanyl phthalocyanine polymorphs, or a substantially pure Type II titanyl phthalocyanine polymorph to a solvent comprised of a trihaloacetic acid and an alkylene halide; adding the resultant solution to a mixture which enables precipitation of Type X oxytitanium phthalocyanine; separating the Type X oxytitanium phthalocyanine from the solution; and thereafter subjecting the Type X oxytitanium phthalocyanine obtained to treatment with a halobenzene, followed by the separation of the Type IV oxytitanium phthalocyanine.
The disclosures of all of the aforementioned publications, laid open applications, copending applications and patents are totally incorporated herein by reference.
Advantages of the processes of the present invention include the use of only two steps to prepare the titanyl phthalocyanine photogenerator pigment; rapid preparation times, for example, in embodiments, 2 hours or less, as compared, for example, about 48 hours to convert from Type IV to Type 1a in methylene chloride, reference U.S. Ser. No. 024,145 (D/92270); and a shorter dwell time of the Type X pigment in the final conversion solvent, which restricts the crystal growth of the Type X pigment and allows a more perfect form of the titanyl phthalocyanine Type 1a to form.


Systems and methods are provided for an air flow sensor assembly for a medical gas flow device. In one embodiment, a system for an air flow sensor assembly for a medical gas flow device includes an air flow passage having a flexible reed positioned therein, the flexible reed fixedly coupled to the air flow passage via an attachment point and having an edge smaller than an inner passage wall of the air flow passage, a planar surface of the flexible reed extending into a flow path of air flow through the air flow passage, and a strain gauge coupled to the planar surface of the flexible reed.

Some types of medical equipment, such as incubators and anesthesia machines, may include an advanced breathing system for moving breathable air into and out of a patient's lungs. The advanced breathing system may include a device for monitoring an air flow rate of the patient's breath. In some examples, the device may include a flexible reed that is perpendicular to the air flow path that is sensitive to changes in air flow through the device. For example, the flexible reed may bend bidirectionally, such as in a first direction during inhalation and a second, opposite direction during exhalation, in proportion to a mass flow rate of each breath. The device may include two pressure ports, one on each side of the flexible reed, to determine a pressure differential across the reed. This pressure differential may be used to determine the mass flow rate of the breath.

Systems and method for an air flow sensor in a medical gas flow device


In some aspects, a method is provided for enhancing electronic device manufacturing throughput within an electronic device manufacturing tool. The method includes the steps of (1) for the electronic device manufacturing tool, creating an electronic device manufacturing schedule based on process factors and mechanical factors associated with the manufacturing tool; and (2) employing the electronic device manufacturing schedule during electronic device manufacturing within the electronic device manufacturing tool. Numerous other aspects are provided.

An event driven algorithm may be employed to control processing of substrates in an electronic device manufacturing facility during electronic device manufacturing. Such event driven algorithms may determine a processing tool is available, determine one or more substrates need to be transported to the processing tool, and transport the one or more substrates to the processing tool. However, such an algorithm may not efficiently route traffic (e.g., the substrates) through or within processing tools during electronic device manufacturing. For example, inefficiencies, such as dead locks and/or bottlenecks (e.g., jams), which adversely affect throughput, may occur during manufacturing. Thus, methods and apparatus are desired for enhancing electronic device manufacturing throughput.

Methods and apparatus for enhancing electronic device manufacturing throughput


Sealant compositions comprising an alkali swellable latex and a pH increasing material and methods of using the same to service a wellbore are provided. In one embodiment, the sealant composition can be used in a wellbore and includes an alkali swellable latex and a pH increasing material. The sealant composition can have a pH of from about 7 to about 14. In other embodiments, the pH increasing material includes a base-producing material. The base-producing material can include alkali and alkali earth metal carbonates, alkali and alkali earth metal bicarbonates, alkali and alkali earth metal hydroxides, alkali and alkali earth metal oxides, alkali and alkali earth metal phosphates, alkali and alkali earth metal hydrogen phosphates, alkali and alkaline earth metal sulphides, alkali and alkaline earth metal salts of silicates, alkali and alkaline earth metal salts of aluminates, water soluble or water dispersible organic amines, polymeric amine, amino alcohols, or combinations thereof.

This invention relates to the field of sealant compositions and more specifically to sealant compositions comprising alkali swellable latex and a pH increasing material as well as methods for using such compositions to service a wellbore.
Natural resources such as gas, oil, and water residing in a subterranean formation or zone are usually recovered by drilling a wellbore down to the subterranean formation while circulating a drilling fluid in the wellbore. After terminating the circulation of the drilling fluid, a string of pipe, e.g., casing, is run in the wellbore. The drilling fluid is then usually circulated downward through the interior of the pipe and upward through the annulus, which is located between the exterior of the pipe and the walls of the wellbore. Next, primary cementing is typically performed whereby a cement slurry is placed in the annulus and permitted to set into a hard mass (e.g., sheath) to thereby attach the string of pipe to the walls of the wellbore and seal the annulus. Subsequent secondary cementing operations may also be performed. One example of a secondary cementing operation is squeeze cementing whereby a cement slurry is employed to plug and seal off undesirable flow passages in the cement sheath and/or the casing. While a cement slurry is one type of sealant composition used in primary and secondary cementing operations, other non-cement containing sealant compositions may also be employed.
Latex emulsions, which contain a stable water-insoluble, polymeric colloidal suspension in an aqueous solution, are commonly used in sealant compositions to improve the properties of those compositions. For example, latex emulsions are used in cement compositions to reduce the loss of fluid therefrom and to reduce the gas flow potential of the composition as the compositions are being pumped to the annulus. Latex emulsions are also employed to reduce the brittleness of the sealant compositions; otherwise, the compositions may shatter under the impacts and shocks generated by drilling and other well operations. Such sealant compositions may be used for sealing the junction of multilateral wells. In addition, latex emulsions are used to improve the flexibility of sealant compositions.
Moreover, latex emulsions are also mixed with drilling fluids, particularly the non-aqueous type, near loss-circulation zones such as natural or induced fractures, thereby forming solid masses for sealing those zones to prevent the drilling fluids from being lost during drilling.
Drawbacks to using latex emulsions include a lack of sufficient strength and elasticity. For instance, sealant compositions containing latex emulsions may be unable to withstand fluid pressures imposed upon the emulsion by drilling operations. Therefore, there are needs for a latex emulsion having increased resistance to downhole fluid pressures.

This patent is subject to a terminal disclaimer.

Oilwell sealant compositions comprising alkali swellable latex


Provided is a substrate processing apparatus that includes: a peripheral exposing unit that performs a peripheral exposing process by irradiating light to a peripheral portion of a substrate while rotating the substrate held by a substrate holding unit using a rotation driving unit; a substrate inspecting unit that performs a substrate inspecting process based on a picked up image of the substrate while moving the substrate using a movement driving unit; and a control unit. The control unit controls the predetermined substrate processing to be stopped when the peripheral exposing process is included in the predetermined substrate processing and an error occurs in the peripheral exposing unit, and controls the substrate inspecting process to be skipped when no error occurs in both of the peripheral exposing unit and a transport unit, the substrate inspecting process is included in the predetermined substrate processing and an error occurs in the substrate inspecting unit.

A photolithography process of a manufacturing process of a semiconductor device includes various processes such as a resist coating process that forms a resist film on the surface of a substrate such as a wafer, an exposing process that irradiates and exposes a pattern formed on the surface of the substrate, and a developing process that develops the substrate after the exposing process. A coating and developing system for performing the respective processes includes a coating device, an exposing device, and a developing device therein, and further, includes a substrate transporting device that transports the substrate among the respective devices.
In the resist coating process, there is a concern that a resist film coated on a peripheral portion of a substrate becomes thick, and as a result, the uniformity of a film thickness of the substrate surface deteriorates or a redundant resist film of the peripheral portion is peeled to generate particles. Therefore, in order to remove the redundant resist film formed at the peripheral portion of the substrate surface, a peripheral exposing process is performed that exposes the peripheral portion of the substrate after the resist coating process. See, for example, Japanese Patent Application Laid-Open No. 2004-14670. Therefore, the coating and developing system includes a peripheral exposing device for performing the peripheral exposing process.
With respect to the substrate after the resist coating process, a substrate inspecting process is performed using a substrate inspecting device to investigate whether a defect such as coating non-uniformity caused by the resist coating process exists on the substrate surface or whether a scratch occurs or a foreign material is attached to the substrate surface. See, for example, Japanese Patent Application Laid-Open No. 2007-240519. For example, an imaging device such as a charge coupled device (CCD) line sensor picks up an image of the substrate by moving relatively with respect to a placing table on which the substrate is disposed and processes the picked up image to determine whether there are defects, scratches, and the attachment of the foreign material. Therefore, the coating and developing system includes a substrate inspecting device having an imaging device and configured to perform a substrate inspecting process.

Substrate processing apparatus, substrate processing method, and computer-readable recording medium having program for executing the substrate processing method recorded therein


In a CDMA receiver of the present invention in accordance with the IS-95 standard, at least one pilot filter is provided externally of a loop for synchronization tracking. Then filtering processing of a pilot signal and synchronization tracking processing is performed concurrently. Further using synchronization establishment information transmitted from a base station, a rate for the synchronization tracking is adaptively changed. Furthermore a time constant of the pilot filter independently provided is set using information from an AFC circuit. According to the present invention, it is possible to perform the filtering processing of the pilot signal assuredly, and to improve the synchronization tracking capability.

1. Field of the Invention
The present invention relates to a receiver used in a Code Division Multiple Access (CDMA) communication system.
2. Description of the Related Art
As CDMA digital car telephone and portable telephone systems, there is known a North American standard system (TIA IS95).
In the standard specification (TIA/EIA/IS-95-A) published by the TIA(Telecommunications Industry Association), chapter 6 has a description concerning functions required for a mobile station, and chapter 7 has a description concerning functions required for a base station.
A brief outline of the North American standard system is as follows:
That is, a basic chip rate is about 1.23 Mcps, and as current accommodated user rates, there are two rates of a 14.4 kbps sequence and a 9.6 kbps sequence. The forward channel includes a pilot channel that all mobile users use commonly, and under a precondition that base stations are synchronous, seamless handover (soft handover) is achieved by acquiring pilot synchronization.
Pilot channel signals are used in estimation of radio channel and coherent detection, or measurement of a base station transmitted signal level.
Further as a signal reception system, there is adopted a RAKE combining reception system. That is, maximal-ratio combining is performed on signals corresponding to different paths received in multipath environment, whereby a received signal is obtained.
It is important in receiving a CDMA signal to perform initial synchronization acquisition and synchronization tracking processing with high rate.
In a CDMA communication, it is planned to increase a bit rate to 64 kbps to enable communications of character information and image information besides speech information. Under a condition that such high rate signal processing is required, capabilities of a synchronization tracking system in the above-mentioned conventional receiver are not necessarily sufficient.
Accordingly if a phase of a received signal rapidly shifts before tracking processing is started after the initial synchronization is established, it is expected that the worst problem may occur that already established synchronization is lost. This case causes the necessity to perform the initial synchronization acquisition processing again.
For example, under such a condition that a mobile station such as an automobile moves along a slop with a height variation with very high speed, when the soft handover is performed, there is expected a case that a phase of a received signal rapidly shits due to switching between base stations, and thereby the synchronization is lost before the tracking processing starts working.
The use of a digital signal processor (DSP) is considered to speed up the tracking processing. In this case, however, power consumption is increased because software loop processing is repeated many times. Further it is considered that capabilities for the other processing in the DSP be decreased by an amount corresponding to an additional program for reception processing.
The present invention is carried out based on the consideration as described above. It is an object of the present invention to reduce the time taken to start the synchronization tracking processing without increasing loads on software and without increasing power consumption, and to speed up the tracking control.
The reason for the long time taken to start tracking processing in a conventional receiver is that a pilot filter to remove a noise from a pilot signal is present in a control loop.
In the present invention, the pilot filter is arranged externally of a path (loop) to perform the synchronization tracking processing. That is, the pilot filter is arranged independently to enable the filtering processing of a pilot symbol and tracking control processing to be performed concurrently.
According to this constitution, it is possible to speed up the processing required to determine a throw amount (a shift amount in reception timing) because it is not necessary to perform the filtering processing of the pilot signal, and consequently to perform smooth synchronization tracking control. Further this constitution does not cause such problems that a load on software is increased and power consumption is increased.
In one aspect of a CDMA receiver of the present invention, at least one pilot filter, which performs filtering on a pilot symbol transmitted from a base station to decrease an interference component, is provided externally of a signal processing loop for synchronization tracking. It is thereby possible to concurrently process the filtering of the pilot symbol and signal processing for the synchronization tracking.
Since the throw amount is determined without waiting for the processing with the pilot filter to be finished, the time taken from signal reception to start tracking control is reduced. Thereby, in performing a soft handover, such an inconvenience hardly occurs that once established synchronization is lost.
Further in another aspect of the CDMA receiver of the present invention, data indicative of the throw amount of a reception timing is generated from a table (look-up table system) when the synchronization tracking is performed while shifting the reception timing per a predetermined interval basis. Then a relationship between inputs and outputs in the table is updated using synchronization establishment information transmitted from the base station.
In the IS-95 CDMA communication system, the forward channel includes a think channel and handover assist channel besides the pilot channel and traffic channel. A mobile station side always receives synchronization establishment information (useful information for synchronization establishment) transmitted from the base, station. Accordingly when the soft handover is performed, the mobile station side knows phase information of a pilot channel signal of the base station to which the communication is switched. The use of the information achieves faster convergence of a tracked phase as compared to a case that tracking control is started under a condition of no preliminarily knowledge. Accordingly tracking control performance is further improved.
Furthermore, in the other aspect of the CDMA receiver of the present invention, a time constant of the pilot filter is updated using information concerning automatic frequency control.
A pilot signal component varies due to carrier frequency offset of a local oscillator at a receiver side, frequency shift caused by fading, and other facts. A range that the pilot signal component is considered to be in (frequency band) is estimated using the information from an automatic frequency control circuit (AFC circuit), and the time constant of the pilot filter (width of a passing band) is changed dynamically. That is, at the time of the soft handover, since a variable parameter value in the AFC circuit is changed, according to the change, the time constant of the pilot is also changed.
It is thereby possible to decrease noise components (interference components) effectively to detect the pilot signal accurately, and therefor to improve a received quality in obtaining a demodulated signal from a received signal. As a result, it is possible to prevent the deterioration of the received quality in performing the soft handover.

Matsushita Electric Industrial Co., Ltd.


Ternary or quaternary electrolyte material for use in thermal batteries that is substantially free of binders is disclosed. Composites of electrodes and electrolytes that contain the electrolyte material and batteries that contain the electrolyte material are also disclosed.

The field of this disclosure generally relates to electrolyte material for use in thermal batteries and, particularly, to ternary or quaternary electrolyte material that is substantially binder-free. The disclosure also relates to composites of electrodes and electrolytes that contain the electrolyte material and cathode and/or anode material and to batteries that contain the electrolyte material.
Thermal batteries tend to have relatively long shelf lives, high energy densities, require relatively low maintenance, and can withstand relatively high temperatures. Thermal batteries also tend to provide a short burst of power over a relatively short period of time. The burst may range from less than a second to an hour or more, with power typically ranging from about a watt or less to kilowatts. Such properties make thermal batteries suitable for military (e.g., batteries for missile guidance systems) and space exploration applications. Thermal batteries may also be used in other applications, such as in electric vehicles.
A typical thermal battery includes an anode, a cathode, an electrolyte-separator containing a solid electrolyte that is non-conductive at ambient temperature, and a pyrotechnic material (e.g., heat pellet as in FIG. 1 which may contain, for example, Fe—KClO4 powder) that provides a heat source to the battery. When battery operation is desired, an external stimulus is applied to the battery. For example, an electrical current may be applied to the battery to set off an electric match or an electro-active squib or a mechanical force (e.g., mechanical shock) may be applied to set off a concussion primer. The external stimulus causes the pyrotechnic material to ignite and begin to heat. Heat produced from the pyrotechnic material causes the previously solid electrolyte to melt and become conductive, which allows the battery to provide power for a desired application.
The anodes of thermal batteries are generally formed of an alkali or alkaline earth metal or alloy. A typical anode includes lithium metal or a lithium alloy, such as lithium aluminum, lithium silicon, or lithium boron.
Electrolytes for use with thermal batteries often include a eutectic mixture (i.e., a mixture which melts at a temperature lower than each of the individual components) of lithium chloride and potassium chloride and a binder, such as MgO, fumed silica or kaolin), which assists in containing the electrolyte within the thermal battery assembly upon melting, such as by capillary action, surface tension, or both. With typical thermal battery electrolytes, without sufficient binder, the electrolyte material may disperse throughout the battery, causing undesired shunts or short circuits in the cell. Unfortunately, the binder materials tend to be relatively resistant to ionic conduction and thus inclusion of the binder increases the impedance of the battery.
Cathode material for thermal batteries may vary in accordance with a variety of design parameters and generally includes a metal oxide or metal sulfide. By way of example, iron oxide (FeO4), iron disulfide (FeS2) or cobalt (CoS2) disulfide are often used as cathode material.
Thermal batteries are often formed using pellet techniques, such that each of the electrolyte, cathode, and heat source are formed into a wafer. In this case, the respective cell component chemicals are processed into powders and the powders are pressed together to form the cell. Each component may be formed as a discrete part, or the anode and/or cathode may include (i.e., be flooded with) electrolyte material to improve the conductivity of the cell.
Although conventionally-used electrolyte material (including cathodes or anodes that contain such electrolyte material and including batteries that include the electrolyte material) work relatively well, the binder adds undesired impedance to the cell. Accordingly, there is a continuing need for thermal battery electrolyte material that allows the amount of binder present in the material to be reduced or even eliminated but yet prevents the electrolyte material from dispersing to portions of the cell that may result in shunts or short-circuits. A continuing need also exists for battery components and batteries that incorporate such electrolyte material.

Thermal battery electrolyte materials, electrode-electrolyte composites, and batteries including same


A computer network-storage protocol system, including at least one initiator device having an initiator block layer and an initiator network layer interfacing with a first network driver; at least one target device having a target block layer and a target network layer interfacing with a second network driver; a plurality of network interface controllers (NICs) interfacing with the first network driver and the second network driver; a plurality of distinct channels, each channel establishing a connection between the initiator device and the target device and being configured to transmit packets between the initiator device and the target device, wherein each channel is mapped to only one NIC; and wherein the initiator block layer includes at least one request message buffer and at least one data message buffer.

In many datacenters, storage is typically a separate tier from application servers and access happens mostly via a storage area network (SAN). Current efforts to improve efficiency of datacenters in terms of reduced energy consumption and reduced operational expenses are focused on creating less expensive storage solutions. One way to do this is to bring storage closer to applications and computation by converging the two tiers. Converged storage advocates placing storage devices, such as solid state disks or non-volatile memory (NVM), in all servers where computation occurs and adapting the current input/output (I/O) stack to the new model. In the converged storage model, many storage accesses require crossing the network for various reasons, such as additional storage capacity, reliability, and sharing. Storage requests are therefore exchanged between all servers, and the network protocol used plays an important role.
There are many advantages to using Ethernet-based physical networks for storage. A single Ethernet network for network and storage data traffic reduces cost and complexity. In the past, there has been a significant amount of research on interconnects that scale and impose low overheads. However, such interconnects are unlikely to dominate and displace Ethernet in the datacenter. For this reason, the network protocol used on top of Ethernet plays a significant role in achieving high efficiency for remote storage access.
Current technology trends for efficient use of infrastructures dictate that storage converges with computation by placing storage devices, such as NVM-based cards and drives, in the servers themselves. With converged storage, the role of the interconnect among servers becomes more important for achieving m high I/O throughput. Given that Ethernet is emerging as the dominant technology for datacenters, reducing protocol overheads for accessing remote storage over Ethernet interconnects is becoming increasingly important.

Network storage protocol and adaptive batching apparatuses, methods, and systems

FOUNDATION FOR RESEARCH AND TECHNOLOGY—HELLAS (FORTH)


An X-Y stage including a fixed plate, a moving plate adapted to linearly reciprocatively move relative to the fixed plate, and an ultrasonic linear motor provided on either the fixed plate or the moving plate. The ultrasonic linear motor is provided with at lest two leg portions oriented in a direction perpendicular to a moving direction of the moving plate, a body portion for connecting base ends of the leg portions, and vibration sources for vibrating the leg portions and the body portion. The leg portions have free ends pressed against the other of the fixed plate on which the motor is not provided and the moving plate.

The present invention relates to an X-Y stage to be used as index table for an electronic equipment or a precision instrument, and more particularly to an X-Y stage having improved driving means.
A conventional X-Y stage is shown in FIGS. 6 to 8. Referring to FIGS. 6 to 8, an X stage 2 is provided over a fixed plate 1 in such a manner as to be linearly reciprocatively movable through ball bearings B in a horizontal direction, and a Y stage 3 is provided over the X stage 2 in such a manner as to be linearly reciprocatively movable through ball bearings C in a horizontal direction perpendicular to the moving direction of the X stage 2.
A stepping motor 4 is fixed to the fixed plate 1 in such a manner as to project sideward from the X stage 2, and a screw shaft 5 is rotatively driven by the stepping motor 4. The screw shaft 5 is threadedly engaged with a nut (not shown) provided in the X stage 2. Thus, the X stage 2 is reciprocable by driving the stepping motor 4.
Similarly, a stepping motor 6 is fixed to the X stage 2 in such a manner as to project sideward from the Y stage 3, and a screw shaft 7 is rotatively driven by the stepping motor 6. The screw shaft 7 is threadedly engaged with a nut (not shown) provided in the Y stage 3. Thus, the Y stage 3 is reciprocable by driving the stepping motor 6.
In the conventional X-Y stage as mentioned above, the rotary motion of the stepping motor 4 as a driving source is converted into the linear motion through the screw shaft 5 and the nut engaging the same, so as to linearly move the X stage 2, for example. Accordingly, a positioning accuracy of the X stage 2 is limited by backlash of the screw shaft 5 and accumulated error. Further, the X stage 2 cannot be moved at a high speed.
Furthermore, as the stepping motor 4 is so located as to project sideward from the X stage 2, the X-Y stage is enlarged in size.
Additionally, it is very hard to machine a long screw shaft 5 with a high degree of straightness. Accordingly, a moving distance of the X stage 2 is limited.
The above-mentioned problems similarly occur in the Y stage 3.
The present applicant invented a high efficient ultrasonic linear motor utilizing a resonance condition of components (Japanese patent application No. 1-55572). The ultrasonic linear motor is constructed of a traveling member (vibrating member) including at least a pair of leg portions adapted to be vibrated in a direction perpendicular to a rail and a body portion connecting the leg portions and adapted to be vibrated in a direction parallel to the rail. The leg portions and the body portion are vibrated by applying voltages having suitably different phases, so that the motor may on the rail.


The invention relates to devices for purifying hydraulic and dielectric fluids (oils and fuels) of mechanical impurities. Electric filter for purifying hydraulic and dielectric fluids comprises a housing with an inlet pipe and outlet pipe, high-voltage power supply, composite unit disposed inside the housing and consisting of current-carrying plates and dielectric spacers with apertures for current-carrying and heavy-duty fastening elements, a front plug and rear plug, and current-carrying and heavy-duty fastening elements, wherein the surface of the current-carrying plates is provided with a porous ceramic dielectric coating. The technical result consists in: increasing the efficiency of purifying dielectric fluids; stabilizing the electromagnetic field of the electric filter; increasing the surface area of the electric filter by creating a developed surface of current-carrying filter elements without changing the filter size and mass; improving reliability and ease of use; and reducing the materials consumption.

The prior art discloses an electric purifier of dielectric fluids consisting of a housing, restraining plates, set of connecting electrodes, float cutoff valve, longitudinal electrical baffles, purified fluid inlet and outlet pipes, insulating pads, covers, mounting studs, power wiring and fastening elements (SU691199, publ. 15.10.1979).
The disadvantage of this device is unstable electromagnetic field due to non-controllable high-voltage power supply of electric filter, variation of electromagnetic field as contaminations are accumulated.
The closest prior art discloses a filter for purifying dielectric fluids characterized in that it comprises a housing consisting of two parts interconnected by flange connections, and housing is fixed at 20°±5°, with the upper part comprising collecting electrode power supply, and the lower one includes a pack of collecting electrode plates with apertures 1 mm wide covering all electrode area, and dielectric plates have apertures 5 mm wide (RU158784, publ. 20.01.2016).
The disadvantages of this device are as follows: low efficiency of dielectric fluid purifying, unstable electromagnetic field due to non-controllable high-voltage power supply of electric filter, variation of electromagnetic field as contaminations are accumulated, poor reliability, unhandiness, high materials consumption.

SCIENCE & PRACTICE LIMITED LIABILITY COMPANY


A system for software error-correcting code (ECC) protection or compression of original data using ECC data in a first memory is provided. The system includes a processing core for executing computer instructions and accessing data from a main memory, and a non-volatile storage medium for storing the computer instructions. The software ECC protection or compression includes: a data matrix for holding the original data in the first memory; a check matrix for holding the ECC data in the first memory; an encoding matrix for holding first factors in the main memory, the first factors being for encoding the original data into the ECC data; and a thread for executing on the processing core. The thread includes a Galois Field multiplier for multiplying entries of the data matrix by an entry of the encoding matrix, and a sequencer for ordering operations using the Galois Field multiplier to generate the ECC data.

1. Field
Aspects of embodiments of the present invention are directed toward a system and method of using parity data for erasure code data verification, correction, encryption, and compression, alone or in combination with each other.
2. Description of Related Art (from the Benefit Application)
An erasure code is a type of error-correcting code (ECC) useful for forward error-correction in applications like a redundant array of independent disks (RAID) or high-speed communication systems. In a typical erasure code, data (or original data) is organized in stripes, each of which is broken up into N equal-sized blocks, or data blocks, for some positive integer N. The data for each stripe is thus reconstructable by putting the N data blocks together. However, to handle situations where one or more of the original N data blocks gets lost, erasure codes also encode an additional M equal-sized blocks (called check blocks or check data) from the original N data blocks, for some positive integer M.
The N data blocks and the M check blocks are all the same size. Accordingly, there are a total of N+M equal-sized blocks after encoding. The N+M blocks may, for example, be transmitted to a receiver as N+M separate packets, or written to N+M corresponding disk drives. For ease of description, all N+M blocks after encoding will be referred to as encoded blocks, though some (for example, N of them) may contain unencoded portions of the original data. That is, the encoded data refers to the original data together with the check data.
The M check blocks build redundancy into the system, in a very efficient manner, in that the original data (as well as any lost check data) can be reconstructed if any N of the N+M encoded blocks are received by the receiver, or if any N of the N+M disk drives are functioning correctly. Note that such an erasure code is also referred to as "optimal." For ease of description, only optimal erasure codes will be discussed in this application. In such a code, up to M of the encoded blocks can be lost, (e.g., up to M of the disk drives can fail) so that if any N of the N+M encoded blocks are received successfully by the receiver, the original data (as well as the check data) can be reconstructed. N/(N+M) is thus the code rate of the erasure code encoding (i.e., how much space the original data takes up in the encoded data). Erasure codes for select values of N and M can be implemented on RAID systems employing N+M (disk) drives by spreading the original data among N "data" drives, and using the remaining M drives as "check" drives. Then, when any N of the N+M drives are correctly functioning, the original data can be reconstructed, and the check data can be regenerated.
Erasure codes (or more specifically, erasure coding systems) are generally regarded as impractical for values of M larger than 1 (e.g., RAID5 systems, such as parity drive systems) or 2 (RAID6 systems), that is, for more than one or two check drives. For example, see H. Peter Anvin, "The mathematics of RAID-6," the entire content of which is incorporated herein by reference, p. 7, "Thus, in 2-disk-degraded mode, performance will be very slow. However, it is expected that that will be a rare occurrence, and that performance will not matter significantly in that case." See also Robert Maddock et al., "Surviving Two Disk Failures," p. 6, "The main difficulty with this technique is that calculating the check codes, and reconstructing data after failures, is quite complex. It involves polynomials and thus multiplication, and requires special hardware, or at least a signal processor, to do it at sufficient speed." In addition, see also James S. Plank, "All About Erasure Codes: —Reed-Solomon Coding—LDPC Coding," slide 15 (describing computational complexity of Reed-Solomon decoding), "Bottom line: When n & m grow, it is brutally expensive." Accordingly, there appears to be a general consensus among experts in the field that erasure coding systems are impractical for RAID systems for all but small values of M (that is, small numbers of check drives), such as 1 or 2.
Modern disk drives, on the other hand, are much less reliable than those envisioned when RAID was proposed. This is due to their capacity growing out of proportion to their reliability. Accordingly, systems with only a single check disk have, for the most part, been discontinued in favor of systems with two check disks.
In terms of reliability, a higher check disk count is clearly more desirable than a lower check disk count. If the count of error events on different drives is larger than the check disk count, data may be lost and that cannot be reconstructed from the correctly functioning drives. Error events extend well beyond the traditional measure of advertised mean time between failures (MTBF). A simple, real world example is a service event on a RAID system where the operator mistakenly replaces the wrong drive or, worse yet, replaces a good drive with a broken drive. In the absence of any generally accepted methodology to train, certify, and measure the effectiveness of service technicians, these types of events occur at an unknown rate, but certainly occur. The foolproof solution for protecting data in the face of multiple error events is to increase the check disk count.
3. Description of Related Art (New)
Parity data is used in digital error detecting and correcting logic, such as erasure codes. An erasure code is a type of error-correcting code (ECC) useful for forward error-correction in applications like a redundant array of independent disks (or devices, also known as RAID) or high-speed communication systems. In a typical erasure code, data (or original data) is organized in stripes, each of which is broken up into N equal-sized blocks, or data blocks, for some positive integer N. The data for each stripe is thus reconstructable by putting the N data blocks together. However, to handle situations where one or more of the original N data blocks get lost (for example, missing, corrupted, etc.), erasure codes also encode an additional M equal-sized blocks (called check blocks or check data; also referred to as parity blocks or parity data) from the original N data blocks, for some positive integer M.
The N data blocks and the M check blocks are all the same size. Accordingly, there are a total of N+M equal-sized blocks after encoding. The N+M blocks may, for example, be transmitted to a receiver as N+M separate packets, or written to N+M corresponding disk drives, or physically or logically separated from each other by some other device or convention. For ease of description, all N+M blocks after encoding will be referred to as encoded blocks, though some (for example, N of them) may contain unencoded portions of the original data. That is, the encoded data refers to the original data together with the check data. Another way to look at this is that the original data can be trivially encoded into N blocks, one for each original data block. Still another way to look at this is that the original N data blocks can be encoded into N+M encoded blocks.
The M check blocks build redundancy into the system, in a very efficient manner, in that the original data (as well as any lost check data) can be reconstructed if any N of the N+M encoded blocks are received by the receiver, or if any N of the N+M disk drives are functioning correctly (or, in short, if any N of the N+M encoded blocks are available). Note that such an erasure code is also referred to as "optimal." For ease of description, only optimal erasure codes will be discussed in this application. In such a code, up to M of the encoded blocks can be lost, (e.g., up to M of the disk drives can fail) so that if any N of the N+M encoded blocks are received successfully by the receiver, the original data (as well as the check data) can be reconstructed. N/(N+M) is thus the code rate of the erasure code encoding (i.e., how much space the original data takes up in the encoded data). Erasure codes for select values of N and M can be implemented on RAID systems employing N+M (disk) drives by spreading the original data among N "data" drives, and using the remaining M drives as "check" drives. Then, when any N of the N+M drives are correctly functioning, the original data can be reconstructed, and the check data can be regenerated.
Systems and methods of implementing practical erasure codes for arbitrary values of N and M are described in the Benefit application and included herein. The advent of such practical implementations allows potentially a large number M of check drives in a RAID environment, some or most of which would not even be needed in a typical failure scenario.
Erasure codes are usually described with an underlying assumption that, at any time, each encoded block is known either to contain entirely correct data or to contain corrupted or missing data. Accordingly, it is only a matter of making sure that there are N encoded blocks that are assumed to have correct data in order to guarantee that the original data can be reconstructed. Silent data corruptions (SDCs), this is, the introduction of errors into the encoded blocks, which can take place in any portion of the memory or storage hierarchy, are therefore assumed not to exist in this framework.
However, studies of real life data show otherwise. SDCs are introduced throughout the memory and storage hierarchy. Left undetected (and uncorrected), SDCs can propagate and compromise data, amplifying their negative effects.
In Li, M. & Shu, J., Preventing Silent Data Corruptions from Propagating During Data Reconstruction, 59 IEEE TRANSACTIONS ON COMPUTERS 1611-24 (vol. 12, December 2010) the authors describe the SDC phenomenon with erasure codes and propose solutions for SDC detection and correction during data reconstruction. However, as already mentioned, SDCs can be introduced anywhere in the memory or storage hierarchy, so it would be desirable to prevent their occurrence anywhere, and not just during data reconstruction.

Using parity data for concurrent data authentication, correction, compression, and encryption


A method for continuously monitoring and/or controlling the cooling capacity of a liquid coolant containing gas bubbles. The method comprising the steps of: (a) measuring the size and number density of the gas bubbles it he liquid coolant by use of a sensor means to infer a heat transfer characteristic of the liquid coolant; and (b) varying the amount of gas that is being mixed with the liquid coolant so that the inferred heat transfer characteristic is within a predetermined range.

Traditionally, continuous casting of light metal ingot has followed the practice of introducing molten metal into one end of an open-ended mold and withdrawing a solid or partially solidified ingot from the opposite end. Typically, the casting mold is relatively short in the axial direction and is hollow or otherwise adapted to receive a liquid cooling medium, such as water, which chills and solidifies the ingot meniscus. The water is then discharged from the mold and continues to chill the ingot as it contacts the ingot surface. Molds are preferably constructed of aluminum but may also be copper, bronze or another material which exhibits high thermal conductivity.
U.S. Pat. No. 4,166,495 issued to Yu discloses an ingot casting method for controlling the withdrawal of heat from the surface of a cooling ingot. The essence of the invention of U.S. Pat. No. 4,166,495 is the mixing of a gas with the liquid coolant before the liquid coolant is applied to the ingot surface. When the gas containing liquid coolant is applied to the mold during the initial stages of casting, the gas mixed in the liquid coolant acts to retard the rate of heat extraction of the liquid coolant. When the amount of gas mixed with the liquid coolant is reduced, the rate of heat extraction by the mold is increased. The increased rate of heat extraction is used on subsequent portions of the emerging ingot length.
The method of U.S. Pat. No. 4,166,495 is a commercially successful method of retarding the cooling effect of the liquid coolant and has come to be known in the aluminum industry as the Alcoa 729 process. The Alcoa 729 process has been successfully used to cast ingot having a width to thickness ratio of 5.3.
This is the largest width to thickness ratio that the applicant knows is commercially feasible for casting ingot and is obtainable only by using the Alcoa 729 process. A preferred coolant of the Alcoa 729 process is water and one preferred gas is CO.sub.2. Water is a preferred coolant because it is inexpensive and abundant. CO.sub.2 is preferred because it is odorless, inexpensive, highly soluble in water and relatively harmless to the environment. In addition, since there is no gaseous buildup in the recycled water, CO.sub.2 does not suffer from many of the disadvantages associated with chemical additives. Other gases which are substantially insoluble in water, such as for example air, may also be used in practicing the method of U.S. Pat. No. 4,166,495.
U.S. Pat. No. 4,693,298 issued to Wagstaff discloses a means and technique for casting metals at a controlled direct cooling rate. The method of U.S. Pat. No. 4,693,298 involves mixing liquid coolant and a gas which is substantially insoluble in the liquid coolant by discharging the gas through jets. The jets release the gas in the flowing liquid coolant as a mass of bubbles that tend to remain discrete and undissolved in the coolant as the coolant on the surface of the ingot.
Although the Alcoa 729 process is economical and effective, it is improvable. The amount of gas that must be mixed with the liquid coolant in the process is very sensitive to changes in temperature, mixing pressure, and water quality. The ability of the gas to retard the heat of extraction of the liquid coolant is determined by the volatility of the liquid, which depends on the concentration of gas mixed in the liquid coolant, the temperature of the liquid coolant, the velocity of coolant flow and the coolant quality of the liquid coolant. The term "quality" as used herein means the chemistry of the liquid coolant and it includes properties such as ph, alkalinity, dissolved and suspended solids, surface tension and ionic species. The sensitivity of the process to changes in temperature and coolant quality requires that the amount of gas that is added to the cooling medium must be constantly adjusted by trial and error so that the desired heat transfer characteristics of the liquid coolant can be maintained. The temperature sensitivity and coolant quality sensitivity of the Alcoa 729 process makes casting of some ingots extremely difficult.
Accordingly, it would be advantageous to provide an economical and effective method of monitoring and controlling the cooling effect of the liquid medium at a desirable level even though the coolant quality and temperature may vary.
The primary object of the present invention is to provide a method and apparatus for monitoring the cooling effect of the liquid medium containing gas bubbles.
Another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which permits a greater control of the rate of heat extraction from a liquid coolant in which gas has been mixed to regulate the cooling rate of the coolant when it is used to cool the surface of a continuously cast ingot.
A further object of the present invention is to provide a method and apparatus for continuously casting ingots that can compensate for changes in the heat transfer characteristics of the cooling medium due to changes in the temperature and coolant changes without dramatic variations in the flow rates of the liquid cooling medium.
Another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which permits a monitoring of the size and concentration of the gaseous bubbles in a liquid medium that is used to cool the surface of a continuously cast ingot.
Yet another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which permits the casting of ingot with a larger width to thickness ratios than has heretofore been commercially feasible.
Another object of the present invention is to provide a method and apparatus that can be readily added to existing commercial casting facilities which permits the casting of ingot with an aspect ratio greater than 5.3.
Still another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which reduces the severity of the most common deformities occurring on the butt end or the initially emerging bottom surface of a continuously cast ingot.
Still another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which will minimize ingot butt curl on the butt end or the initially emerging bottom surface of a continuously cast ingot.
Still a further object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which will increase the safety of ingot startup by minimizing the possibility of an explosive bleed out in the butt end or the initially emerging bottom surface of a continuously cast ingot.
Still another object of the present invention is to provide a method and apparatus that can be readily added to existing casting facilities which will (a) monitor and control the transition from a liquid coolant containing gaseous CO.sub.2 to a non-gaseous liquid coolant and (b) minimize the ingot deformation that is normally associated with the transition.
These and other objects and advantages of the present invention will be more fully understood and appreciated with reference to the following description.

Method and apparatus for controlling the heat transfer of liquid coolant in continuous casting


A finishing grindstone member (20) is fixed to a spindle (10) by a bolt. In the spindle (10), there is formed a tool mounting portion (25) into which a rough grindstone member can be mounted. Into the tool mounting portion (25), there can be mounted not only the rough grindstone member but also a cover member (36). After a silicone wafer is roughly ground using the rough grindstone member, when finish grinding the silicone wafer using the finishing grindstone member (20), the cover member (36) is mounted onto the tool mounting portion (25) to thereby prevent the tool mounting portion (25) from being soiled.

1. Field of the Invention
The present invention relates to a working apparatus such as a one-surface grinding apparatus which is used to work the back surface of a wafer with an IC (Integrated Circuit), an edge grinding apparatus for working the edge of a circular-shaped thin plate and a machining center for performing many kinds of workings with many kinds of working tools.
2. Description of the Related Art
For example, in producing an IC tip, after an IC (Integrated Circuit) is produced on one surface of a mirror-surface silicone wafer, as a wafer""s back surface working operation, a grinding operation is executed on the other surface of the silicone wafer. In this case, firstly, one surface, namely, the back surface of the silicone wafer is roughly cut using a rough grindstone. After completion of the rough cutting operation, the thus rough cut surface is ground using a finishing grindstone to thereby carry out a finishing treatment on the same.
Also, in grinding a circular-shaped thin plate such as a semiconductor wafer, surface grinding is firstly executed. After completion of the surface grinding, the outer peripheral edge of the semiconductor wafer is ground. Conventionally, as such wafer edge grinding, only the rough grinding is executed; but, recently, for the wafer edge grinding as well, there has been requested finishing grounding. Therefore, in the wafer edge grinding operation as well, the wafer edge is firstly ground roughly and, after then, finish grounding is executed on the roughly ground edge of the wafer.
When one surface of the wafer is ground, conventionally, there is used a one surface grinding apparatus which uses, for example, two spindles. In this one surface grinding apparatus, a rough grindstone is mounted on one of the two spindles, while a finishing grindstone is mounted on the other. And, the wafer is roughly ground using the rough grindstone mounted on one spindle and, after then, the wafer is moved to the position of the other spindle and is then finish ground using the finishing grindstone.
And, there is also used a one surface grinding apparatus which uses a spindle. In the case of this one surface grinding apparatus, a grindstone is mounted onto the spindle by a bolt and is then used to grind one surface of a work. More specifically, in this grinding apparatus, when the roughness of the grindstone must be changed as a grinding process progresses, for example, an operator unbolts the bolt to thereby remove the grindstone by hand and, next, the operator mounts a new grindstone onto the spindle.
However, of the above-mentioned two conventional one surface grinding apparatus, in the case of the one surface grinding apparatus using two spindles, because two spindles are necessary, the whole one surface grinding apparatus is complicated in structure and large in size. Also, there is further necessary a delivery device which is used to deliver a work between the two spindles.
On the other hand, in the case of the one surface grinding apparatus using a spindle, it is necessary to replace the grindstone each time the grinding process progresses. This raises a problem that the operator has to take much time and labor. Also, because the grindstone must be manually replaced by the operator, it takes long time to complete the whole grinding operation.
In order to solve the above problems, for example, there is known a one surface grinding machine which is disclosed in JP-A-1-257555. This one surface grinding machine comprises a plurality of cup-type grindstones disposed concentrically with one another and differing in diameter and kind from one another, and drive means for driving these cup-type grindstones individually. And, the plurality of cup-type grindstones are capable of executing grinding operations ranging from a rough grinding operation up to a finish grinding operation on a work in accordance with the feeding movements of the work. In the case of this one surface grinding machine, the whole apparatus (that is, the whole of the one surface grinding machine) can be made compact.
However, in the one surface grinding machine disclosed in the above-cited publication, in case where the grindstone is worn and degraded, an operator replaces the degraded grindstone with a new grindstone by hand. Therefore, not only it takes time and labor to grind the work, but also it takes time to execute the grindstone replacing operation. This drawback is also caused in the conventional edge grinding machine as well.
The present invention aims at eliminating the above drawbacks found in the conventional working apparatus. Accordingly, it is an object of the invention to provide a working apparatus which is simple in structure and small in size, does not cost an operator enormous labor, and is capable of executing a grinding operation in a short time.
In attaining the above object, there is provided a working apparatus for working a work, including: a spindle fixedly mounted with a first working tool for working the work in a specific manner. The spindle is formed with a tool mounting portion mountable onto a second working tool.
Accordingly, in a spindle onto which a grinding tool can be mounted, there is formed a tool mounting portion such as a grindstone mounting portion; and, a grinding tool such as a grindstone to be mounted into the tool mounting portion can be replaced using an automatic tool replacement device. Thanks to this, a single spindle can be used and, when compared with a structure using two spindles, the whole one surface grinding apparatus can be reduced in size.
Also, an operation to replace a worn grinding tool can be facilitated, an operator can be set free from enormous time and labor necessary for the grinding tool replacing operation, and the grinding operation can be executed in a short time. Further, since the grinding operation can be carried out while replacing a grindstone with a second grindstone having different roughness, the grinding operation can be carried out with high efficiency as a whole.


An image forming apparatus comprises: a rotatable image carrier operable to carry a toner image on a surface thereof; a transfer part operable to electrostatically transfer the toner image carried on the surface of the image carrier, onto a transfer material; a cleaning member that is in contact with the surface of the image carrier and that is operable to clean toner remaining on the surface of the image carrier after transfer by the transfer part; and a voltage supplier operable to apply, to the cleaning member, a bias voltage that is for cleaning the surface of the image carrier and that has a polarity opposite to a normal charging polarity of the toner. Here, application of the bias voltage by the voltage supplier starts before rotation of the image carrier starts, and when Vr>0, 0<Vc<Vr, and when Vr<0, Vr<Vc<0, where Vc is a value of the bias voltage from a start of the application until a start of the rotation, and Vr is a reference value which is a value of the bias voltage from the start of the rotation onward.

(1) Field of the Invention
The present invention relates to an image forming apparatus that includes a rotatable image carrier and a cleaning member which is in contact with a surface of the image carrier.
(2) Related Art
Image forming apparatuses such as copiers that are able to form color images include so-called tandem-type image forming apparatuses. Tandem-type image forming apparatuses have a structure such as follows: photosensitive drums for colors of, for example, C (cyan), M (magenta), Y (yellow), and K (black) are arranged along an intermediate transfer belt; toner images formed on the photosensitive drums are primarily transferred in a sequential manner onto the surface of the rotating intermediate transfer belt to be superimposed at a same position; and the toner images for the respective colors primarily transferred onto the surface of the intermediate transfer belt are collectively secondarily transferred onto a recording sheet.
According to the above-described structure, it is desirable that the entirety of the toner images on the intermediate transfer belt is secondarily transferred onto the recording sheet. However, in reality, part of the toner images remains on the surface of the intermediate transfer belt without being transferred. Accordingly, a cleaning unit for cleaning the toner remaining on the intermediate transfer belt (residual toner) is provided at a position that is downstream, in the belt moving direction, relative to the secondary transfer position.
One example of such a cleaning unit is an electrostatic-adsorption type cleaning unit whose cleaning brush applied with a bias voltage abuts onto the surface of the intermediate transfer belt and which electrically removes the residual toner by adsorbing it to the cleaning brush. The residual toner adsorbed to the cleaning brush is collected by a collection roller provided adjacent to the cleaning brush.
In a case of using this electrostatic adsorption method, the residual toner remaining in the cleaning brush (attached to the bristles of the brush) cannot be kept attracted to the cleaning brush without application of a bias voltage to the cleaning brush. Accordingly, if the intermediate transfer belt is rotated without the application of the bias voltage, the bristles of the brush abutting the belt surface move mechanically due to the rotation of the intermediate transfer belt, and this movement causes the residual toner remaining in the brush to come out toward the belt surface, smearing the belt surface by attaching thereto. Thus, a control is performed such that the bias voltage is applied to the cleaning brush first, and after that, the rotation of the intermediate transfer belt starts. However, such a control, that is, applying the bias voltage to the cleaning brush when the intermediate transfer belt is not rotating, causes the bias voltage to be continually applied from the start of the voltage application until the start of the rotation of the intermediate transfer belt. This leads to accumulation of unnecessary electric charge at the intermediate transfer belt at its belt portion which abuts against the cleaning brush.
The cleaning unit may have a smoke prevention seal for preventing toner smoke provided at its end portion in the downstream in the belt moving direction; and in a vicinity positioned downstream relative to the cleaning unit in the belt moving direction, a filming preventive member made of foam sponge may be provided in contact with the surface of the intermediate transfer belt, in order to scrape off external additives and the like of the toner which the cleaning brush could not remove. Consequently, once the intermediate transfer belt starts rotating, when the belt portion having the unnecessary electric charge remaining thereon passes by the smoke prevention seal and the filming preventive member, the toner having been attached to the smoke prevention seal and the filming preventive member is attracted by the charge remaining at the belt portion and may move to the belt surface, smearing it as a result.
Such a problem occurs not only to intermediate transfer belts, but also may occur to structures having a cleaning member that electrically removes residual toner on an image carrier, such as a structure using a photosensitive drum as the image carrier.

Image forming apparatus including a cleaning member having a bias voltage

Konica Minolta Business Technologies, Inc.


An ink formulation comprises a binder and at least one marking component, which comprises at least one metal oxide or oxyanion and at least one oxidizing/reducing agent, which absorbs laser irradiation between wavelengths of 780-10,600 nm, thereby causes the formulation to change color.

Pigments have been proposed, which can be used to mark a substrate by the application of laser energy. Reference can be made to WO-A-00/43456, JP-A-11001065, EP-A0522370, EP-A-0797511, U.S. Pat. Nos. 5,053,440; 5,350,792; 5,928,780; 6,017,972; 6,019,831; 5,489,639 and 5,884,079.
WO02/01250 discloses the use of oxymetal salts in laser marking. AOM (ammonium octamolybdate) is an example of a material that can be marked directly with 10,600 nm laser radiation.
WO05/068207 discloses the use of NIR laser radiation (i.e. at 800 to 2000 nm) to initiate a color change reaction when a NIR-absorbing metal salt is used in combination with a substance that normally undergoes a color change reaction at much longer wavelength (about 10,600 nm), e.g. AOM.
JP8127670 discloses the use of reduced titanium oxide compounds for incorporation into thermoplastics, for the laser marking of molded products.
U.S. Pat. No. 5,911,921 discloses the use of non-stoichiometric ytterbium phosphate to produce NIR absorbing inks, e.g. for printing stealth bar codes.

Reaction-based laser marking compositions, systems and methods


A clock data recovery circuit includes: a first detecting circuit for detecting phases of an incoming data signal and a sampling clock signal to generate a first detection signal; a loop filter for generating a control signal according to the first detection signal; a second detecting circuit for detecting phases of a reference signal and a feedback signal to generate a second detection signal; a control voltage generating circuit for generating a control voltage based on the second detection signal; a voltage-controlled oscillator for generating the sampling clock signal according to the control voltage; a phase adjustment circuit for adjusting the phase of the sampling clock signal according to the control signal to generate the phase-adjusted signal; and a frequency divider circuit for conducting a frequency division operation on the phase-adjusted signal to generate the feedback signal.

The disclosure generally relates to a clock data recovery circuit and, more particularly, to a clock data recovery circuit capable of accelerating the loop response speed and does not easily result in frequency drift.
A clock data recovery circuit is widely employed in many applications, but the conventional clock data recovery circuit typically uses the analog loop filter. Therefore, in the situation of that the input terminal of the clock data recovery circuit does not receive any data signal over a certain period of time, it easily causes frequency drift in the resulting sampling clock signal.
The frequency drift problem may be reduced by replacing the analog loop filter with more complex digital loop filter, but it would easily result in insufficient loop response speed, thereby causing the conventional clock data recovery circuit to be unable to support applications having higher data signal frequency.


A configurable optical communications system (100) for establishing point-to-point communications between multiple computer servers (160) coupled to a common midplane or backplane communications bus (132), wherein at least two of the servers include an optical input/output device (170) for sending and receiving an optical signal (112). The system further includes an optical communications pathway (140) that is configured to carry the optical signal, and at least two pivotable mirrors (150) located within the optical pathway and in-line with the optical input/output devices that are selectively orientated to direct the optical signal between the optical input/output devices to establish the point-to-point communication between the at least two servers.

The growth of the Information Technology sector in the economy has led providers of on-line information and services, in-house enterprise data management groups, government agencies and others to establish high-volume data processing centers, also known as server farms, to process, manage and store large amounts of information. The constant pressures to increase bandwidth, processing power, storage capacity and reliability has resulted in high-density computational platforms and architectures, such as blade servers installed in standardized rack enclosures and assembled into server towers.

Configurable point-to-point optical communications system between servers

Hewlett-Packard Development Company, L.P.