Abstract: A method for producing a high concentration of hydrogen peroxide by reacting oxygen and hydrogen directly in a neutral reaction medium that contains a promoter comprising a halogen containing compound, which halogen containing compound contains at least one halogen other than fluorine, at a reaction temperature in the range of from 0.degree. to 50.degree. C. and at a reaction pressure in the range of from 3 to 150 kg/cm.sup.2 .multidot.G in the presence of a platinum group metal catalyst supported on a catalyst carrier containing a heteropolyacid that has been made insoluble in water or a platinum group metal catalyst supported on a catalyst carrier comprising activated carbon that is supporting a heteropolyacid.

Abstract: Oxygen and hydrogen are catalytically reacted in an acidic reaction medium in the presence of a platinum group metal catalyst to prepare hydrogen peroxide using as a carrier for the platinum group metal catalyst a composite oxide containing cerium. The process need not halogen ions in the acidic reaction medium and enables preparation of hydrogen peroxide in high concentration on an industrial scale advantageously.

Abstract: A structure for preventing the dislocation of a spring is provided in an optical disk cartridge wherein a shutter (23) is opened and closed in accordance with a sliding movement of a sliding jig (24) provided in the inner portion of the shutter and joined to the spring contacting portions of cartridge case via a spring (27). The spring contacting portions of the cases consist of the surfaces of a contacting wall (32), and upper (33) and lower (34) walls extending from the contacting wall, the lower wall being provided with a spring dislocation preventing projection (36).

Abstract: A method for producing a high concentration of hydrogen peroxide by reacting oxygen and hydrogen directly in a reaction medium containing a promoter such as a halogen containing compound using a platinum group metal catalyst supported on a solid acid carrier or a solid super acid carrier.

Abstract: This invention provides a method for high efficiency, high concentration production of hydrogen peroxide wherein oxygen and hydrogen are reacted in the reaction medium in the presence of a catalyst comprising a metallic or carrier supported platinum group metal catalyst onto which an organic halogen compound which is insoluble in water, which compound excludes compounds which contain no halogen other than fluorine, has been adsorbed or a platinum group metal catalyst supported on a carrier in which a halogenated organic compound, which compound excludes compounds that contain no halogen other than fluorine, has been adsorbed to the carrier prior to supporting the platinum group metal. Since it is not necessary for halogen ions to be present in the reaction medium as it was in the prior art, the problems of deterioration due to the dissolution of the catalyst and of corrosion of the structural materials of the reaction vessel are alleviated.

Abstract: A dispersion of reactive polymer particles obtained by polymerization of monomer in an organic liquid which dissolves the monomer but does not dissolve a polymer formed from the monomer, in the presence of a dispersion stabilizer composed of a high molecular weight polymer; characterized in that (i) said dispersion stabilizer is a high molecular weight polymer which is obtained by polymerization of an ethylenically unsaturated monomer and soluble in the above organic liquid and which contains a chemically reactive group (A); that (ii) said polymer particles are particles of a high molecular weight polymer which are obtained by polymerization of an ethylenically unsaturated monomer and contain a complementary chemically reactive group (B) capable of mutually reacting with the chemically reactive group (A); and that (iii) the chemically reactive group (A) and the chemically reactive group (B) are present stably in the dispersion.

Abstract: A method for producing hydrogen peroxide by the reaction of hydrogen and oxygen in the reaction medium in the presence of a platinum group metal catalyst supported on a halogenated resin, in which, since there are no halogen ion nor high concentrations of acid in the reaction medium of this invention as there are in prior art methods, the problems of dissolution of catalyst and corrosion of the reaction vessel are solved.

Abstract: A book case type optical disk storage container adapted to house a cartridge type optical disk with its shutter opened, the container being characterized in that one storage surface of the container is provided with a shutter stopper for keeping the shutter open, and a projection for supporting an optical disk base rotatably, the other storage surface being provided with a disk rotating jig and a disk base cleaning device. A structure for preventing the dislocation of a spring is provided in the optical disk cartridge wherein a shutter is opened and closed in accordance with a sliding movement of a sliding jig provided in the inner portion of the shutter and joined to the spring contacting portions of cartridge case via a spring. The spring contacting portions of the cases consist of the surfaces of a contacting wall, and upper and lower walls extending from the contacting wall, the lower wall being provided with a spring dislocation preventing projection.

Abstract: An injection mold for injection molding a plastic substrate for high-density information recording medium. An annular sliding member is axially slidably supported in the circumference of a disk-shaped cavity of a mold half. The annular sliding member is biased toward the surface of a disk-shaped cavity provided in another mold half so as to form the molding cavity and maintain contact with said surface during molding of said plastic substrate.