Abstract: The present invention relates to fine particles in which desired magnetic particles are enclosed, the fine particles being easy to handle, having a large surface area, being resistant to settling, being compact, and having a functional group such as a carboxyl group on the particle surface. The fine particles include at least one type of polyolefin or polyolefin copolymer and at least one type of magnetic material, are substantially spherical particles having a density of 0.9 to 1.5 g/cc and an average particle size of 0.5 ?m to 1,000 ?m, and have a functional group on the particle surface.

Abstract: The present invention relates to fine particles having a controlled density, the fine particles forming a stable dispersion in a dispersion medium comprising water as a primary component, and being less prone to precipitating or settling. In the present invention, fine particles having a controlled density comprise at least one type of polymer and at least one type of filler, the fine particles having a volume average particle diameter of 0.01 ?m to 1,000 ?m and a density of 0.9 to 2.0.

Abstract: A method for producing a porous body with high porosity is provided.An adhesive is coated on a synthetic resin foam having three-dimensional network structure, such as urethane foam, serving as a base material, to impart stickiness to the surface of the resin foam, and thereafter a powder such as copper oxide powder is applied thereto, followed by heating to remove the substrate and sinter the powder. Thus, a porous body to which the pattern of the base material has been transferred is produced.The powder may be appropriately selected to obtain porous bodies having a great strength, without limitations on materials.

Abstract: Properties of a compound semiconductor single crystal (e.g. GaAs single crystal) can be homogenized by subjecting the single crystal covered with a metal oxide powder (e.g. Ga.sub.2 O.sub.3 powder) to a heat treatment.

Abstract: A radiation detector containing as a scintillator a combination of two or more single crystals of cerium doped gadolinium silicate having different Ce concentrations, or a single crystal of cerium doped gadolinium silicate having different Ce concentrations therein, is improved in a spatial resolution and a time resolution.

Abstract: It is disclosed that a Heusler alloy thin film having a structure of a single crystal is prepared by forming a Heusler alloy thin film having a magneto-optical effect and an MgAgAs type crystalline structure on a single crystal substrate, whereby magnetization is easily effected in a low applied magnetic field. This single crystal thin film is suitable as a material of a head for writing magnetically and reading out optically.

Abstract: A magnetic recording medium having a magnetic film formed on a substrate directly or through an underlayer from an alloy containing Co as a principal component. The central line average surface roughness Ra and maximum surface roughness Rmax of the magnetic film in a direction perpendicular to the direction of magnetic recording are selected so as to fall within the ranges of 1 nm.ltoreq.Ra.ltoreq.20 nm and Rmax.ltoreq.25 Ra, respectively, and the in-plane magnetic anisotropy energy Ku of the magnetic film is selected to fall within the range of 0.ltoreq.Ku.ltoreq.8.times.10.sup.5 erg/cm.sup.3. Thus, it is possible to minimize the value of modulation which represents the degree of variation of read output on the same circumference of a magnetic disk. It is also possible to reduce the noise generated in read and write operations by forming the magnetic film so as have no crystallographic orientation.

Abstract: There is provided a piezoelectric transducer comprising a substrate having a single crystal plate comprising strontium titanate or magnesium oxide, a first electrode comprising metal films so formed on the substrate as to leave openings exposing the surface of the substrate, a piezoelectric thin film comprising lead titanate as the main component formed so as to cover the openings and the first electrode, and a second electrode formed on the piezoelectric thin film.

Abstract: Optical glass is produced by heating a porous gel to a high temperature to partly sinter it, heating it in a chlorine-containing atmosphere to subject it to hydroxyl group removal treatment, and then further heating it to sinter it. The optical glass produced by this process does not rise in bubbles even when heated.

Abstract: A method for producing optical glass, which comprises charging a mixed solution capable of forming a high-silica-content gel by hydrolysis reaction into a vessel, the inner wall face of which is composed of a material unwettable to the mixed solution, such as a fluorocarbon resin or silicone resin, causing gelation of the mixed solution in the vessel, drying the obtained gel, and heating and sintering the obtained dry gel. When electrodes are placed in the mixed solution at the gelation step and an electric voltage is applied, the time required for formation of the gel is shortened. Furthermore, at the gel-drying step, if the amount of materials evaporated from the gel is detected or the weight of the gel is measured, the detected amount of the evaporated materials or the change of the weight of the gel is fed back to a factor regulating the drying speed, such as the drying temperature to control the drying speed to an appropriate level.

Abstract: A process for producing a mother rod useful for the production of an optical fiber which comprises hydrolyzing a silicon alkoxide to prepare a gel of a desired shape, and drying and sintering the gel to produce a block made of a silica glass. The process has the advantages that it is well adapted for mass-production, that a glass made of a B.sub.2 O.sub.3 --SiO.sub.2 system may be produced thereby and that a glass block of arbitrary shape may be readily produced.

Abstract: A method for producing silica glass wherein a dry silica gel subjected to a water desorption treatment and a carbon removal treatment is heated and has its temperature raised in an atmosphere containing chlorine, to perform a hydroxyl group removal treatment, the resultant silica gel is thereafter heated to a temperature of approximately 1,000.degree. C.-1,100.degree. C. in an atmosphere containing at least 1% of oxygen, to perform a chlorine removal treatment, and the resultant silica gel is further heated to a temperature of 1,050.degree. C.-1,300.degree. C. in He or in vacuum, to perform a sintering treatment. The silica glass thus produced does not form bubbles even when heated to high temperatures of or above 1,300.degree. C. Therefore, it is easily worked and it is free from the lowering of transparency attributed to the bubble formation.

Abstract: A method for producing an optical fiber preform comprising the steps of blowing, through at least one nozzle, gaseous material producing glass material soot by a CVD reaction to permit the glass material soot to be deposited on a target to produce a soot rod which grows in size, and heating and rendering transparent the soot rod produced in the first step, wherein a pipe is arranged substantially concentrically with the glass material soot so as to permit gas to flow through a clearance between the deposited glass material soot and the inner wall surface of the pipe in a direction in which the soot rod grows in size. The method makes it possible to prevent the outer peripheral portion of the soot rod from becoming porous and to satisfactorily control the diameter of the soot rod.

Abstract: In synthesizing cubic boron nitride from hexagonal boron nitride under high temperature and high pressure conditions, if water is incorporated into the raw material in an amount of at least 3% by weight, cubic boron nitride of a higher purity in the form of smaller crystallites than in conventional products can be obtained under lower temperature and lower pressure conditions than in conventional methods. When graphitic hexagonal boron nitride is used as the raw material, the temperature and pressure necessary for synthesis can be reduced to about 600.degree. C. and 50 Kbar, respectively.