Abstract: A process for synthesizing a large diamond having a diameter of 8 mm or more by the temperature gradient method, wherein a (111) or (100) surface of a seed crystal having a diameter of 3 mm or more is used as a growing surface, the entire area of the growing surface is first dissolved in the diamond-stable region before crystal growth is started, the crystal growth is effected using a plug of a solvent in which the height of the central portion thereof is higher than the height of the peripheral portion thereof, the plug of a solvent has a planar or curved surface on the side where the plug of a solvent contacts a carbon source during the crystal growth, and the crystal growth is effected under such pressure and temperature conditions that the growth of the (111) or (100) surface is predominant.

Abstract: A method for growing crystals of sodium beta" alumina is described. The crystals are grown by Czochralski type processes or analogous methods wherein single crystals are formed from a flux or melt. The melt is a eutectic type liquid primarily containing Na or K, (Li, Mg or other divalent element, e.g. Ni.sup.2+, Co.sup.2+, Cr.sup.2+, Fe.sup.2+, etc.) Al, in proportions to produce beta" alumina. To lower the melt temperature to where e.g. Na.sub.2 MgAl.sub.10 O.sub.17 beta" or Na.sub.2 Li.sub.1/2 Al.sub.11/2.degree.17 beta" can crystallize in its stability region (approximately less than 1700.degree. C. for the Mg version and approximately less than 1600.degree. C. for the Li version) high valent ions, which do not enter the structure, particularly V.sup.5+, Nb.sup.5+, Ta.sup.5+, Zr.sup.4+ and/or Hf.sup.4+ are added to the melt. The method has allowed the growth of single crystals of the Li-stabilized sodium and potassium varieties for the first time.

Abstract: A chrysoberyl solid laser host which comprises a chrysoberyl matrix doped with trivalent titanium ions for luminescence is described. This host ensures a lasing operation over a wide wavelength range and is highly producible and high in quality.

Abstract: A jewelling and ornamental material comprising many amorphous silica spheres regularly arranged in a three-dimensional array and a zirconium compound filled in pores existing among the amorphous silica spheres, the amount of the zirconium compound being 0.005 to 8% by weight, as zirconium, based on the entire material; and a process for its production. This material has a play of colors inherent to natural opal, and excellent durability.

Abstract: Disclosed is a process for the production of a zirconia type black decorative article which comprises sintering an unsintered molded body comprising a matrix composed mainly of zirconia and at least one stabilizer contained in the matrix, said stabilizer being selected from Y.sub.2 O.sub.3, MgO, CeO.sub.2 and CaO, at a temperature of 1400.degree. to 1600.degree. C. in a non-oxidizing atmosphere so that the molded body becomes black, and subjecting the sintered body to the mirror polishing treatment. The decorative article prepared according to this process has a black and glossy mirror surface and also has high flexural strength and high toughness.

Abstract: In order to produce a chrysoberyl single crystal displaying a luminous band effect, a mixture of a principal component consisting of beryllium oxide and aluminum oxide in nearly equal molar amounts with small amounts of titanium oxide and coloring metal oxide is sintered or melted and solidified in a non-oxidizing gas atmosphere to provide a raw material bar; the raw material bar is heated in a non-oxidizing gas atmosphere by means of a light condense-heating type floating zone method to grow a chrysoberyl single crystal; and the single crystal is heated so as to allow needle crystals of titanium oxide to be deposited in one orientation in the chrysoberyl single crystal.

Abstract: Disclosed is a chrysoberyl cat's-eye synthetic single crystal, which comprises aluminum oxide and beryllium oxide as main component, and 0.005 to 1.050% by weight, based on the total crystal, of at least one member selected from oxides of iron, cerium, vanadium, cobalt, tungsten, chromium, nickel and manganese and 0.005 to 2.0% by weight, based on the total crystal, of at least one member selected from oxides of titanium, tin, zirconium and germanium.This synthetic single crystal is comparable to natural cat's-eye in the physical properties, color tone and chatoyancy effect.

Abstract: A jewelling and ornamental material comprising many amorphous silica spheres regularly arranged in a three-dimensional array and a zirconium compound filled in pores existing among the amorphous silica spheres, the amount of the zirconium compound being 0.005 to 8% by weight, as zirconium, based on the entire material; and a process for its production. This material has a play of colors inherent to natural opal, and excellent durability.

Abstract: A cathode ray tube (1) having a body (3) of glass material and a faceplate (5) of solid phosphor material. The body (3) and faceplate (5) are sealed together by a sealant (15) of malleable halide material--for example silver chloride, or lead-silver chloride eutectic. Sealing is effected by inserting a ring (15) of sealant material between abutting surfaces of the body (3) and the faceplate (5), heating in vacuum to above the melting point of the sealant, and cooling to allow the sealant to solidify. The faceplate (5) may be of single crystal material--e.g. zinc tungstate or calcium borate, or may be of hot pressed solid material--e.g. zinc yttrium silicate.

Abstract: An imitation gem consisting of a semi shell of a transparent plastic material with concave inner and convex outer surfaces has light reflecting and light refracting facets formed on both its inner concave and outer convex surfaces. The open end of the semi shell is closed by a cover which is also provided with facets so as to further improve light reflection and refraction.

Abstract: A method for preparing reversible-photochromic magnesium oxide (MgO) crystals. Single crystals of MgO doped with both lithium (Li) and nickel (Ni) are grown by a conventional arc fusion method. The as-grown crystals are characterized by an amber coloration. The crystals lose the amber coloration and become photochromic when they are thermochemically reduced by heating at temperatures greater than 1000.degree. K. in a hydrogen atmosphere. Alternate irradiation with UV and visible light result in rejuvenation and bleaching of the amber coloration, respectively.

Abstract: A method of reoxidizing a partially-reduced ceramic. The partially reduced eramic is heated in a chamber having a non-oxidizing atmosphere. An oxidizing gas is then introduced into the chamber at a rate which is sufficiently slow that cracking will not occur.

Abstract: A single-crystalline jewelry material based on aluminium garnets of the general formula: Re.sub.3 Al.sub.5 O.sub.12, wherein Re=Y, Dy, Ho, Er, Tm, Lu and containing two dyeing additives. One of the additives is selected from the group consisting of europium in an amount of from 10.sup.-3 to 3% by weight or ytterbium in an amount of from 0.1 to 61.3% by weight and the other is selected from the group consisting of zirconium or silicon in an amount of from 10.sup.-4 to 1% by weight, or hafnium in an amount of from 10.sup.-3 to 3% by weight. The material has a color smoothly changing from green to violet.

Abstract: A single-crystalline material based on aluminium garnets of the general formula Re.sub.3 Al.sub.5 O.sub.12, wherein Re=Y, Dy, Ho, Er, Lu and containing a dyeing additive of a red color spectrum, viz. specifically zirconium, in an amount ranging from 10.sup.-2 to 3% by weight.

Abstract: A fabrication technique is described for making various devices in which a certain type of glass is used as a surface protection layer. The glass layers are formed by particle bombardment (generally sputtering or E-beam) of a glass target. Devices with such surface layers are also described. Such glass layers are highly advantageous as encapsulating layers, diffusion barrier layers, etc., particularly for optical type devices and certain semiconductor devices. Particularly important is the preparation procedure for the glass target used in the bombardment process. The glass layers are moisture stable, act as excellent barriers against diffusion, and are usable up to quite high temperatures (i.e., in diffusion doping procedures) without cracking or peeling. The glass layers also provide long-term protection against atmosphere components including water vapor, oxygen, atmosphere pollution contaminants, etc., and can be removed by standard etching techniques.

Abstract: This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m.

Abstract: A single crystal substrate for epitaxial growth thereon of a semiconductor layer. The substrate consisting essentially of sapphire (aluminum oxide) and at least one additive selected from a group consisting of oxides of gallium. A 87 mol percent content of gallium oxide is most preferred for a silicon layer. Similarly, an additive and its content should most preferably be selected depending on the semiconductor, which may be gallium phosphide, aluminium phosphide, or zinc sulphide.

Abstract: Diamond crystals of controlled impurity content and/or impurity distribution and reaction vessel configurations for the production thereof are described. Combinations of "dopant", "getter" and "compensator" materials are employed to produce gem stones of unusual color patterns, or zoned coloration, using specific reaction vessel configurations.

Abstract: A ceramic mixture for production of ceramic articles includes, in % weight, clay 1-64, ore selected from the group consisting of iron ore and manganese ore 30-98, and at least one metal oxide 0.1 -12.

Abstract: A single crystal substrate for epitaxial growth thereon of a semiconductor layer. The substrate consists essentially of sapphire (aluminum oxide) and scandium oxide (Sc.sub.2 O.sub.3). The invention also provides the aforesaid single crystal substrate in combination with a semiconductor epitaxially grown thereon. The preferred semiconductors are silicon, gallium phosphide, aluminum phosphide and zinc sulphide.

Abstract: A single crystal substrate for epitaxial growth thereon of a semiconductor layer. The substrate consists essentially of sapphire (aluminum oxide) and magnesium titanium oxide (MgTiO.sub.3). The invention also provides the aforesaid single crystal substrate in combination with a semiconductor epitaxially grown thereon. The preferred semiconductors are silicon, gallium phosphide, aluminum phosphide and zinc sulphide.

Abstract: A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.