63results about How to "Reduced impurity levels" patented technology

High-surface-area carbon nanostructures coated with a smooth and conformal submonolayer-to-multilayer thin metal films and their method of manufacture are described. The preferred manufacturing process involves the initial oxidation of the carbon nanostructures followed by immersion in a solution with the desired pH to create negative surface dipoles. The nanostructures are subsequently immersed in an alkaline solution containing non-noble metal ions which adsorb at surface reaction sites. The metal ions are then reduced via chemical or electrical means and the nanostructures are exposed to a solution containing a salt of one or more noble metals which replace adsorbed non-noble surface metal atoms by galvanic displacement. Subsequent film growth may be performed via the initial quasi-underpotential deposition of a non-noble metal followed by immersion in a solution comprising a more noble metal. The resulting coated nanostructures may be used, for example, as high-performance electrodes in supercapacitors, batteries, or other electric storage devices.

To control the precipitation position of a crystal and increase the yield of the crystal by performing the crystal growth according to the solvothermal method while allowing a predetermined amount of a substance differing in the critical density from the solvent to be present in the reaction vessel; and to prevent mixing of an impurity into the crystal and improve the crystal purity.

Impure aromatic carboxylic acids such as are obtained by liquid phase oxidation of feed materials comprising aromatic compounds with substituent groups oxidizable to carboxylic acid groups, or comprising aromatic carboxylic acid and one or more aromatic carbonyl impurities that form hydrogenated species more soluble in aqueous solvents or with less color or color-forming tendencies than the aromatic carbonyl impurity, are purified to an aromatic carboxylic acid product with lower levels of impurities by a process comprising contacting an aqueous solution comprising the impure aromatic carboxylic acid with hydrogen at elevated temperature and pressure with an attrition-resistance, acid stable catalyst composition comprising at least one hydrogenation catalyst metal and a support comprising relatively high surface area silicon carbide.

High-surface-area carbon nanostructures coated with a smooth and conformal submonolayer-to-multilayer thin metal films and their method of manufacture are described. The preferred manufacturing process involves the initial oxidation of the carbon nanostructures followed by a surface preparation process involving immersion in a solution with the desired pH to create negative surface dipoles. The nanostructures are subsequently immersed in an alkaline solution containing a suitable quantity of non-noble metal ions which adsorb at surface reaction sites. The metal ions are then reduced via chemical or electrical means. The nanostructures are exposed to a solution containing a salt of one or more noble metals which replace adsorbed non-noble surface metal atoms by galvanic displacement. The process can be controlled and repeated to obtain a desired film coverage. The resulting coated nanostructures may be used, for example, as high-performance electrodes in supercapacitors, batteries, or other electric storage devices.

Crystals of lithium tetraborate or alpha-barium borate had been found to be neutron detecting materials. The crystals are prepared using known crystal growing techniques, wherein the process does not include the common practice of using a fluxing agent, such as sodium oxide or sodium fluoride, to reduce the melting temperature of the crystalline compound. Crystals prepared by this method can be sliced into thin single or polycrystalline wafers, or ground to a powder and prepared as a sintered compact or a print paste, and then configured with appropriate electronic hardware, in order to function as neutron detectors.

A semiconductor fabrication reactor according to the invention comprises a rotatable susceptor mounted to the top of a reactor chamber. One or more wafers are mounted to a surface of the susceptor and the rotation of the susceptor causes the wafers to rotate within the chamber. A heater heats the susceptor and a chamber gas inlet allows semiconductor growth gasses into the reactor chamber to deposit semiconductor material on said wafers. A chamber gas outlet is included to allow growth gasses to exit the chamber. In a preferred embodiment, the inlet is at or below the level of said wafers and the outlet is preferably at or above the level of the wafers. A semiconductor fabrication system according to the invention comprises a source of gasses for forming epitaxial layers on wafers and a source of gasses for dopants in said epitaxial layers. A gas line carries the dopant and epitaxial source gasses to a reactor for growing semiconductor devices on wafers, and the source gasses in the gas line are injected into the reactor chamber through a reactor inlet. The reactor comprises an inverted susceptor mounted in a reactor chamber that is capable of rotating. One or more wafers are mounted to a surface of the susceptor, the rotation of the susceptor causing the wafers to rotate within the chamber. A heater heats the susceptor and the source gasses deposit semiconductor material on the wafers.

A vaporizing device is provided for control, delivery, and purification of low vapor pressure gases in conjunction with carrier gas in micro-electronics and other critical applications.

Herein disclosed is a method of removing at least one component from a feed by subjecting the feed to high shear in the presence of carbon dioxide to produce a high shear-treated product and separating the at least one component from the high shear-treated product to produce a component-reduced product. Also disclosed is a method of removing asphaltenes from asphaltenic oil by subjecting the asphaltenic oil to a shear rate of at least 10,000 s⁻¹ in the presence of carbon dioxide to produce a high shear-treated product and separating asphaltenes from the high shear-treated product to produce an asphaltene-reduced product oil. Systems are also provided for carrying out the methods.

A silica glass crucible for pulling up a silicon single crystal including an outer layer formed from a natural silica glass layer, and an inner layer formed from a synthetic silica glass layer, wherein the synthetic silica glass layer includes a first synthetic silica glass layer formed in a region within a certain range from the center of a crucible bottom section, and a second synthetic silica glass layer formed in a region which excludes the formation region of the first synthetic silica glass layer, and wherein the first synthetic silica glass layer has a thickness of 0.5 mm or more and 1.5 mm or less and a concentration of an OH group included in the first synthetic silica glass layer being 100 ppm or less.

Process for producing an alkyl carboxylate, comprising contacting in an oxidation reaction zone a C₂ to C₄ alkane, a molecular oxygen-containing gas, the corresponding alkene and optionally water, in the presence of at least one catalyst active for the oxidation of the alkane to the corresponding alkene and carboxylic acid, to produce a first product stream comprising alkene, unreacted alkane, carboxylic acid and water; separating in a first separation means at least a portion of the product stream produced in the oxidation reaction zone into a gaseous stream comprising alkene and unreacted alkane and a liquid stream comprising carboxylic acid and water; and separating by chemical treatment at least a portion of the gaseous stream obtained from the first separation means into respective streams rich in alkene and alkane; wherein the chemical treatment comprises the steps of: (1) contacting the alkene/alkane gaseous stream with a solution of a metal salt capable of selectively chemically absorbing the alkene to produce a chemically absorbed alkene-rich liquid stream, and (2) recovering an alkene rich stream from the metal salt solution. In a second reaction zone, at least a portion of the alkene rich stream obtained from the second separation means and a corresponding carboxylic acid are contacted, in the presence of at least one catalyst active for the production of alkyl carboxylate, to produce a second product stream comprising alkyl carboxylate.

A method for the directional solidification of silicon or other materials. A cooled plate is lowered into a silicon melt and an ingot of solid silicon is solidified downwards

There is provided an induction-melting apparatus capable of exhibiting high refining performance without inflicting damage to a crucible even if a halide-compound base refining flux is used upon induction-melting of an ultrahigh-purity high melting-point metal, having a melting point reaching 1500° C., and a method for induction-melting using the same. There is also provided a melting method for enabling production of ultrahigh-purity Fe-base, Ni-base, and Co-base alloying materials, each having an impurity level of (C+O+N+S+P)<100 ppm, and Ca<10 ppm, and in the form of a large ingot. Further, with the induction-melting apparatus, a plurality of tubular segments are disposed so as to be cylindrical in shape, a gap in a range of 1.5 to 15 mm in distance is provided between the respective tubular segments adjacent to each other, and a layer composed of any substance selected from the group consisting of single chemical elements of halides of metal elements of the specific of the Periodic Table of the Elements, or from mixtures of the halides, oxides, and carbides, or nitrides of the metal elements is formed in each of the gaps, and on an inner peripheral surface of a peripheral body part of a crucible. There is also provided method for induction-melting an Fe-base alloy, and so forth, using a halide-base flux while forcibly cooling the crucible. A refining flux composed of any selected from the group consisting of metal elements of the Groups IA, IIA, or IIIA of the Periodic Table of the Elements, oxides thereof, halides thereof, halide single elements or halides selected from the group of halides, or mixtures of the metal elements, and the oxides thereof is added to be thereby turned into a molten state, primary melting is executed by holding a state of a molten metal being in contact with the refining flux before tapping, the molten metal is caused to undergo solidification inside a mold, thereby producing a primary ingot and subsequently secondary melting is executed by an electron-beam melting method whereby while the primary ingot is sequentially melted in a water-cooled copper mold at a low pressure, the molten metal as-solidified state is pulled out from an outlet side of the water-cooled copper mold, thereby forming an ingot product.

According to the present invention there is provided a hydrocarbon synthesis catalyst comprising a precipitated iron product and a catalyst promotor. The catalyst has a surface area of below 60 m² per gram of catalyst in the reduced form or below 100 m² per gram of catalyst in the non-reduced form. According to the invention there is also provided a process for preparing the catalyst and the use thereof in the synthesis of hydrocarbons.

A semiconductor processing component formed of SiC, wherein an outer surface portion of the component has a surface impurity level that is not greater than ten times a bulk impurity level of the outer surface portion.

The present invention relates to a direct method to convert fine and ultra fine silicon powder from polysilicon manufacturing sources such as fluid bed and free space reactors into densified granular forms. This conversion process is effected by the use of lasers of selective wavelengths from solid state diode or optically-pumped YAG sources to locally heat, melt and densify a controlled quantity of silicon powder, and comprises the steps of distributing dry silicon powder on an inert substrate, subjecting the silicon charge to a focused laser beam to realize melted and densified granular forms, and discharging the product. When adapted to high purity silicon powder, the end use for the densified silicon granular forms is primarily as feedstock for silicon-based semiconductor and photovoltaic manufacturing industries. The process, suitably modified, is adaptable to form other silicon body shapes and components.