Abstract: A method for synthesizing beryl crystals from a raw material substantially that of natural beryl and at least one material of molybdates, vanadates and tungstates to form a flux is provided. The raw material and oxides are melted and a rotating beryl seed crystal is placed in contact with the rotating melt zone and drawn away from melt zone so that beryl crystal is synthesized as the seed crystal is withdrawn from the melt zone. The melt zone may be formed in a zone floating furnace with rotating axes or in a rotating crucible.

Abstract: A method is described for removing a CVD semiconductor layer from an alkali halide salt substrate following the deposition of the semiconductor layer. The semiconductor-substrate combination is supported on a material such as tungsten which is readily wet by the molten alkali halide. The temperature of the semiconductor-substrate combination is raised to a temperature greater than the melting temperature of the substrate but less than the temperature of the semiconductor and the substrate is melted and removed from the semiconductor by capillary action of the wettable support.

Abstract: A process for preparing a single crystal comprising drawing up a single crystal by the Czochralski process and cooling it at a temperature not lower than 600.degree. C. at a reduced pressure or in vacuo, by which a single crystal having a dislocation density of 1.5.times.10.sup.4 cm.sup.2 or less is prepared.

Abstract: This invention relates to growing single crystals of urea having increased dimensions on the 110-110 faces by physically restricting growth of the 111 faces of a seed crystal while precipitating urea from a saturated alcoholic solution containing ammonium bromide. In addition, this invention relates to a seed crystal holder adapted to modify crystal habit during crystal growth.

Abstract: A catalytic converter includes a longitudinally disposed body portion having first and second shell halves and an interior in which first and second catalytic substrates are disposed. A divider is positioned between the first and second catalytic substrates and is selectively attachable to accommodate substrates of various relative sizes. The divider includes first and second divider halves, with each divider half having a pair of flanges which extend perimetrically and substantially completely along the interior wall of one shell half. The portion of the interior wall of each shell to which the divider flanges are attached has a greater longitudinal extent than the longitudinal extent of the pair of divider flanges to allow selective placement of the dividers in the converter body portion. The divider flanges are disposed substantially parallel to the interior wall and are coupled thereto. The divider flanges include a portion which is recessed inwardly from the interior wall.

Abstract: A method of growing a single crystal layer of silver thiogallate having a maximum thickness of 50 micrometers. This crystal is of a high purity having a higher degree of crystalline perfection than the substrate on which it is grown. The crystal is grown epitaxially from a solution of silver thiogallate in a solvent of either antimony sulfide or lead sulfide. The solution is prepared by heating a mixture of the materials (solid silver thiogallate in molten solvent) slowly at a rate of, for example, 3.degree. to 5.degree. C. per minute until the mixture reaches a temperature about 10.degree. C. above the liquidus, and maintaining this temperature for 16 hours or more. The above referenced solution is then gradually cooled at a rate of, for example, 1.degree. C. per minute to the temperature at which crystal growth is to be initiated. At this temperature a polished single crystal substrate of a material which has an appropriate lattice relationship with silver thiogallate is dipped into the molten solution.

Abstract: An apparatus and method for atomic absorption spectrophotometric measurement of submicrogram amounts of mercury utilizing a combined absorption-reduction cell sized to fit within the absorption compartment of a standard spectrophotometer. The absorption-reduction cell comprises an absorption chamber which is generally cylindrical in shape and a mixing chamber connected to the lower portion of the absorption chamber into which the sample to be analyzed and a reductant are added. The cell also includes an inlet port, and outlet port, and an air intake port used to flush and clean the cell after use.

Abstract: A thin film of a metal of which eutectic or compound is produced together with a semiconductor which is to be grown in its crystalline form is deposited on an amorphous (quartz glass) substrate. The thin film is patterned with a periodic pattern of a polygon having cross angles of multiples of about 60.degree., then the resulting substrate is heated at a temperature higher than the eutectic temperature of the metal and the semiconductor, and the semiconductor is deposited on the thin film under such heating condition, so that a crystalline film of the semiconductor is precipitated on the substrate. Such crystalline film is grown on a planar substrate at a low temperature of about eutectic temperature.

Abstract: A temperature control system used to precisely and accurately control the temperature of a fluid stream in an analytical system designed for investigation of the chemical constituents of the fluid stream. One example of use is in chromatography such as for the chromatographic column in an amino acid analyzer system. The temperature control system utilizes a set of thermoelectric modules to transfer heat between a thermoconductive block which holds the chromatographic column and an air exchange heat sink which obtains heat from or disposes heat into ambient air as required. The control system regulates the temperature at a very rapid rate in order to minimize the recycle time of the instrument.

Abstract: An improvement in the Czochralski single crystal growing of a rare earth-gallium garnet such as gadolinium gallium garnet according to which the single crystal boules of a relatively large diameter and outstandingly free from any crystal defects and inclusions are readily obtained. The improved method comprises keeping the melt of the oxide mixture formed in an iridium crucible for at least 15 hours in the molten state before crystal growing is started. It was also shown that addition of certain additive gases, e.g. water vapor, carbon dioxide and oxygen, to the gaseous atmosphere mainly composed of, for example, nitrogen, in which crystal growing was performed, in a limited proportion was effective to further improve the crystal quality and to decrease the particulate inclusions in the single crystal boules.

Abstract: Method of extracting magnesium sulphate from mixtures constituted essentially of magnesium sulphate heptahydrate and sodium chloride by means of heat treatment, grinding and dry grading.

Abstract: Wet chemical, microcomputer-controlled procedure for the rapid dissolution of metal followed by accurate determination of elements in the sample and, more specifically, suited to meet steel industry requirements for control of the level of acid-soluble aluminum in steel during the making of steel, is described. A sample of steel to be tested is normally placed in an electrolytic cell wherein a known portion of the sample is dissolved electrolytically in dilute cold acid. The aluminum content of the resulting solution is determined spectrophotometrically. The apparatus is compact and readily installed near the steelmaking operation.

Abstract: Process for the liquid phase epitaxial deposition on a substrate of a ternary compound crystallizing in the same system as the substrate and complying with formula A.sub.x B.sub.n-x C.sub.m in which A, B and C are elements of the periodic classification of elements, n and m are integers, which can be the same or different, and x is between O and n, wherein said process comprises:(a) preparing an epitaxy bath by raising one of the elements A or B of the ternary compound and a stoichiometric solid binary compound of the two other elements of the ternary compound to a temperature such that there is formed with an excess of the said binary compound in the solid state, a liquid phase whose composition corresponds to the equilibrium with the solid phase A.sub.x B.sub.n-x C.sub.m,(b )contacting the bath with the substrate to be coated, and(c) depositing thereon, the ternary compound A.sub.x B.sub.n-x C.sub.m.

Abstract: A protected trigger usable in initiating crystallization of a supercooled salt solution comprises a thin metallic strip containing multiple openings. The strip is protected as by a peripheral frame and/or by a metallic coating.

Abstract: For water treatment in swimming pools, cooling towers, hot tubs, and other systems it is desired to feed various chemicals in small quantities but at optimum rates into the system. In several embodiments of the invention the water is recirculated through the system which usually includes a filter. It has been discovered that the chemicals can be fed by enclosing them in generally spherical plastic capsules suggestive of table-tennis balls, but about the size of a base ball. The rate of feeding depends upon the size and number of small holes which are provided, or the user pokes through the shell of the capsule, upon the solubility of the chemical, and upon the flow rate of the water through a strainer, skimmer, or other chamber in the system into which the capsule is introduced. The random orientation of the capsule tends to average out variations.

Abstract: An epitaxy bell of transparent fused silica is provided with a flanged, thick-walled tubular piece of transparent fused silica on the side on which a process gas is exhausted. The wall thickness of the constricted portion of the bell is increased toward the transparent fused silica tubular piece.

Abstract: A system for the precipitation of Al(OH).sub.3 from green liquor is provided which comprises process and apparatus for feeding the green liquor into the bottom of a chamber containing a supersaturated solution of alumina and Al(OH).sub.3 seed particles. The flow of green liquor into the bottom of the chamber is maintained at a rate sufficient to suspend the seed particles in the chamber with minimum turbulence so that the liquor is in approximately plug flow. As Al(OH).sub.3 precipitates on the seed particles, the particles grow larger and gradually move to the bottom of the chamber where they are removed. The solution, somewhat depleted with respect to Al.sub.2 O.sub.3, overflows the chamber to return to the process.

Abstract: A crucible for semiconductor technology purposes, especially for the production of silicon crystals, comprising an outer layer portion or layer of silicon dioxide, especially an outer made from granular natural quartz, and an inner lining made from synthetic crystalline quartz is described. The inner lining has on its interior surface a thin amorphous layer suitably made by heating a synthetic quartz layer disposed over a granular natural quartz layer at a sufficient temperature for a sufficient period of time to convert at least a portion of the synthetic crystalline quartz to the amorphous state.

Abstract: This apparatus involves an assembly of a test tube and paddle insert. The tube has a frustoconical body and a tapered tip in which is a well, having opposed tapered wide flat walls and narrow walls. The paddle insert has a long handle integral with a transparent tapered paddle head that is shorter than the tapered well in which the paddle head seats. Flexible fingers extend away from the head to frictionally engage the narrow walls of the well and prevent the paddle from falling out of the tube when the tube is inverted or tipped. A ridge on the edges of the side walls and the back of the paddle head retains a specimen in a narrow chamber defined between adjacent walls of the tube tip, the paddle head and the ridge for microscopic examination thereof.

Abstract: A process for manufacturing boron-doped GaAs single crystals which comprises preparing a mixture of boron, gallium and arsenic covered by a liquid B.sub.2 O.sub.3 encapsulant, melting the mixture, pulling up boron-doped GaAs crystals from the mixture melts in accordance with the LEC method, crushing those crystals into small pieces after removing the seed end therefrom, remelting those pieces in the presence of B.sub.2 O.sub.3, and pulling up single crystals from the mixture melts in accordance with the LEC method.