Abstract: A method for producing a semiconductor power device, includes forming a gate trench from a surface of a semiconductor layer toward an inside thereof. A first insulation film is formed on an inner surface of the gate trench. The method also includes removing a part on a bottom surface of the gate trench in the first insulation film. A second insulation film having a dielectric constant higher than SiO2 is formed in such a way as to cover the bottom surface of the gate trench exposed by removing the first insulation film.

Abstract: Provided is a vertical agitating apparatus which can shorten the time of vertically uniform mixing, uniformalize flow rates in the vertical direction, and shorten the time of heat transmission in a deep liquid agitating tank, an agitating tank having a conical bottom part with an acute apex angle of less than 60 deg. or in a tank combination of the former two tanks, and in which a rotary shaft is arranged in the tank so as to be rotatable by a drive located outside of the tank, bottom paddle blades having a large area are attached to the lower part of the rotary shaft, and lattice blades in combination of vertical grids and horizontal arms are provided to the rotary shaft above the bottom paddle blades, the distance between the outer edge of the vertical blades at the outermost end of the lattice blade and the center of the rotary shaft being set so as to be greater than that of the bottom paddle blades.

Abstract: A polyester resin, polyester-imide resin or polyester-amide-imide resin dissolved in a solvent containing 60% by weight or more of at least one polyhydric alcohol derivative selected from the group consisting of R.sub.1 COO(CHR.sub.2 CH.sub.2 O).sub.n H, R.sub.1 COO(CHR.sub.2 CH.sub.2 O).sub.n COR.sub.3, R.sub.1 O(CHR.sub.2 CH.sub.2 O).sub.n COR.sub.3 and R.sub.1 O(CHR.sub.2 CH.sub.2 O).sub.n R.sub.4, wherein R.sub.1, R.sub.3 and R.sub.4 are independently lower alkyl, aryl or aralkyl; R.sub.2 is hydrogen or methyl; and n is an integer of 1 to 3, gives an electrical insulating coating having excellent storage stability and high resin concentration without causing defects of phenols when used as a solvent.

Abstract: An electrical insulating resin composition comprising a resin obtained by reacting (a) one or more tri- or higher polyhydric alcohols and/or tri- or higher polybasic acids, (b) one or more dihydric alcohols, (c) one or more dibasic acids, (d) one or more monobasic acids containing one or more aromatic rings in the molecule, and/or (e) one or more monohydric alcohols containing one or more aromatic rings in the molecule, and if desired (f) one or more compounds containing or being able to form one or more 5-membered imide rings, can give high solids varnishes without lowering the molecular weight of the resin produced. Said varnishes can give coating films excellent in heat resistance, flexibility and mechanical strengths.

Abstract: A resinous composition comprising (a) a low-odor crosslinkable monomer obtained by reacting a glycidyl ester of synthetic or vegetable oil fatty acid with acrylic acid or methacrylic acid with heating, and (b) a polybutadiene modified by acrylic acid or methacrylic acid or an unsaturated polyester resin produces almost no or very little odor in the state of a varnish and at drying or curing. Said composition can produce varnishes excellent in mechanical and electrical properties.

Abstract: In making films or molded articles from polyamide, polyimide, or polyamide-imide resins, the problem of stripping or release is successfully solved by applying a noble metal layer on the surface of a film-casting belt or plate or a casting mold to be in contact with the resins.

Abstract: A thermosetting resin composition is derived from a modified novolak-type resin obtained by the reaction of a phenolic compound with an aralkyl halide or ether. The thermosetting resin is composed of 20 to 80 parts by weight of a thermosetting resin prepared by reacting a modified novolak-type resin represented by, for example, the general formula, ##SPC1##Wherein R is an aromatic nucleus, with formaldehyde in the presence of a basic catalyst, and, in admixture therewith, 80 to 20 parts by weight of a thermosetting resin prepared by reacting the above-mentioned modified novolak-type resin with hexamethylenetetramine. The thermosetting resin is quickly curable and gives a cured article excellent in heat resistance.