Abstract: Mercapto group-containing silicone rubber compositions essentially consisting of a mercapto group-containing organopolysiloxane having a viscosity exceeding 100,000 cSt and represented by the average unit formulaR.sub.a SiO.sub.(4-a/2)in which R is a monovalent hydrocarbon group substantially free from aliphatic unsaturation, at least two of the R groups in a molecule being mercaptoalkyl groups and a is between 1.98 and 2.05, a certain filler and sulfur, a metal oxide or a metal peroxide as a curing agent. Products from the composition have excellent chemical and mechanical properties and can be bonded to an organic synthetic rubber or natural rubber as well as metals in completely cured state.

Abstract: The invention provides a novel elastomer composition capable of giving vulcanized rubber products with superior solvent resistance, oil resistance, heat resistance and other properties. The composition is formulated with a polymer blend of an ethylene-propylene copolymeric elastomer and a specific organopolysiloxane having certain amount of mercapto-substituted organic groups bonded to the silicon atoms as the base component admixed with a filler and a crosslinking agent or a vulcanizing agent.

Abstract: A mesa region of a stripe geometry is formed by mesa-etching a surface of a GaAs crystal substrate, forming a crystal layer of higher resistivity than the abovementioned crystal substrate so as to fill the abovementioned mesa-etched recesses in a manner that the stripe shaped mesa region is buried in the higher resistivity regions making top faces of the mesa region and the higher resistivity regions flush with each other, then forming, on the abovementioned flush surface, several epitaxial growth regions of semiconductor crystal including a light emitting region, for instance, an active region for lasing, subsequently forming contact isolation region having an opening of the stripe geometry corresponding to and above said mesa region. The current flow in the active region is confined in a narrow stripe region.

Abstract: In a semiconductor laser with light guide, wherein an active region to form the Fabry-Perot cavity is formed in a mesa part on a semiconductor substrate and mixed crystal semiconductor parts formed to fill the mesa-etched parts constitute light guides. The improvement is that a crystal semiconductor of the active region has the composition of Ga.sub.1-x Al.sub.x As (0.ltoreq.x<1) and a mixed crystal of the light guide has the composition of GaAs.sub.1-y P.sub.y (0<y<1) or Ga.sub.1-z Al.sub.z As (0<x<z<1) of sufficiently high (for instance, 10.sup.4 .OMEGA.cm) specific resistivity with respect to that of the active region, the value of y or z being selected to be smallest at a depth of the light guide where the lasing light is incident, and the energy gap of the mixed crystal part being selected to be larger than that of said active region, so that light loss in the light guide is decreased.

Abstract: The curable composition provided by the present invention comprises a butadiene polymer having organosilicon groups as the pendant groups, an ethylenically unsaturated polymerizable compound, an organic peroxide, and optionally a filler. The butadiene polymer being the base of this composition can readily be obtained by the platinum-catalyzed addition reaction between an organosilicon compound having a hydrogen atom directly bonded to the silicon atom in a molecule and the ethylenic unsaturation of a conventional butadiene polymer.The compositions of the invention are remarkably superior in many respects to those composition based on ordinary butadiene polymers, and useful for applications in a wide variety including the production of electrically insulating materials and various kinds of industrial articles.

Abstract: A surface of a semiconductor substrate is coated with a mask having a desired doping pattern and the ions of a desired element are accelerated using the mask so that the structure of a predetermined region is changed. Thereafter the doped region or the region not doped is etched and removed.

Abstract: Improved organopolysiloxane compositions curable at room temperature into rubber-like elastomers comprisingA. a hydroxy-terminated diorganopolysiloxane,B. a substituted-aminoxy group containing organopolysiloxane,C. a salt of a metal, such as, calcium, zinc, aluminum, tin and iron, andD. an inorganic filler, such as, calcium carbonate, magnesium hydroxycarbonate and calcium hydroxide, having a basicity sufficient to compensate for the acidity of component c).The compositions exhibit uniform curability throughout the depth of the mass of the composition, even at relatively high temperatures.

Abstract: The organopolysiloxane compositions comprising (a) a linear diorganopolysiloxane having a block structure composed of alternately linked two kinds of blocks of dimethylsiloxane units on one hand and of dimethylsiloxane units and methylvinylsiloxane units on the other hand, (b) a silica filler, (c) a methylhydrogenpolysiloxane as a crosslinking agent, and (d) a platinum catalyst for accelerating crosslinking by addition reaction. Cured silicone rubber elastomers obtained from the composition have very excellent mechanical properties, especially tear strength.

Abstract: Silicone rubber compositions comprising a diorganopolysiloxane gum, an inorganic filler, a vinyl-containing organopolysiloxane resin, polyester fibers cut in a specific length, an amino- or mercapto-containing organosilane or organopolysiloxane as a coupling agent, and an organic peroxide as a curing agent. The novel compositions are capable of giving excellent mechanical properties, especially tear strength, to cured products or silicone elastomers, their other properties being as good as the conventional silicone rubber elastomers.

Abstract: Double-hetero-structure injection laser can be improved to have low threshold current in room-temperature continuous-wave operation. The improvement is obtained in one case wherein an n-type Ga.sub.1.sub.-y Al.sub.y As region (1.gtoreq.y>0) is first formed, a Ga.sub.1.sub.-z In.sub.z As is grown thereon as an active region and a p-type Ga.sub.1.sub.-y Al.sub.y As region is then formed on the active region and the value of z is so selected as to make the lattice constants of the active region smaller than those of the first and third regions.

Abstract: Silicone rubber compositions comprising (a) diorganopolysiloxane with a viscosity at least 1,000,000 centistokes at 25.degree. C, of which from 8 to 80 mole % of the organic groups are monovalent hydrocarbon group having from 2 to 4 carbon atoms, (b) an organopolysiloxane with a viscosity at most 200 centistokes, (c) a silica filler, and (d) an organic peroxide. Their vulcanized form, i.e., silicone rubber elastomers exhibit a high degree of elasticity in an extremely low temperature range, and have superior properties with respect to heat-resistance, oil-resistance, electrical characteristics and compression set.

Abstract: A double-heterostructure injection laser can be improved to have a low threshold current. The improvement is obtained when the active region of GaAs or Ga.sub.l-y Al.sub.y As consists of several component layers wherein the central layer has the highest carrier concentrations and the layers on both sides of the central layer have lower carrier concentrations and the farther the outer layers are apart from the central layer, the lower are their carrier concentrations.By forming the active region in this manner, the light generated in the active region is well confined in the region without undesirable leaking, resulting in a considerable lowering of the threshold current.

Abstract: The organopolysiloxane compositions comprising an organopolysiloxane expressed by the general formulaR.sub.a.sup.1 (R.sub.a.sup.1 A.sub.3.sub.-a SiQ--).sub.b SiA.sub.4.sub.-a.sub.-bwhere R.sup.1 is a monovalent hydrocarbon group, A is a diorganosiloxy group with a functional group at the chain end, Q is a divalent group and a and b are each 0 or 1, and an organosilane or an organopolysiloxane expressed by the general formulaY--SiR.sub.2.sup.2 --O).sub.p SiR.sub.2.sup.2 Y or ##STR1## where R.sup.2 is a monovalent hydrocarbon group, Y is a functional group and p is an integer smaller than 11. The compositions are capable of curing at room temperature into a rubber-like elastomer with a very low modulus and a high elongation as high as 1400% or more.

Abstract: Heat-curable organopolysiloxane compositions comprising a diorganopolysiloxane having at least two vinyl groups per molecule and a viscosity exceeding 100 centistokes at 25.degree. C, an inorganic filler, an organohydrogenpolysiloxane containing at least two Si--H linkages per molecule, a platinum catalyst, a hydrazine compound and optionally, an organic peroxide, which have an improved storage stability and allow for imparting an excellent flame retardancy and mechanical strength to the cured material.

Abstract: Silicone rubber compositions consisting essentially of an organopolysiloxane containing in a molecule at least one linearly-linked cyclic siloxane unit and at least two alkenyl groups directly bonded to silicon atoms, an organohydrogenpolysiloxane, and a platinum catalyst. These compositions are cured to form solid elastomers which exhibit a very low permeability to water vapor, and are useful for enclosing electronic units.

Abstract: Silicone rubber compositions comprising a diorganopolysiloxane having localized vinyl group distribution, a silica filler with large specific surface area and a curing agent, e.g., an organic peroxide, the diorganopolysiloxane being prepared by the block-copolymerization of a hydroxy-endblocked diorganopolysiloxane without unsaturation and a chlorine-endblocked vinyl-containing diorganopolysiloxane by the dehydrochlorination-condensation. Cured elastomers from silicone rubber compositions have very much improved tear strength with the other properties being as good as those of the conventional silicone rubber elastomers.

Abstract: Silicone compositions consisting essentially of 100 parts by weight organopolysiloxane, 20-200 parts by weight finely divided silica filler, 5-100 parts by weight finely divided manganese carbonate, and 5-1,000 ppm platinum alone or in a platinum containing material, based on the weight of the organopolysiloxane. Finished products prepared by molding the compositions exhibit particularly excellent flame-proofing and improved degrees of permanent strain caused by stress. Particularly preferred are silicone compositions with 5-100 parts by weight of finely divided manganese carbonate having a particle size from about 1.mu. to about 50.mu..