Abstract: In a magnetic recording medium comprising on a non-magnetic substrate a magnetic layer obtained by dispersing ferromagnetic powder in an electron beam-curable resin followed by electron beam curing or a backcoat layer obtained by curing an electron beam-curable resin with electron beams, a combination of an electron beam-curable vinyl chloride resin having a sulfur-containing polar group and an electron beam-curable urethane resin having a phosphorus-containing polar group is used as the electron beam-curable resin. This results in improvements in dispersibility, surface smoothness, and electromagnetic characteristics, as well as a lowering of error rate in high density digital recording. Storage property is good.

Abstract: A filter apparatus that is compact and that provides a large filtration area includes filter elements each constructed in cylindrical form by spirally winding a filter medium. Such medium includes a porous membrane of a polytetrafluoroethylene having a pore diameter of 0.1 to 5 .mu.m and low pressure loss and one or a pair of sheets composed of fibers made of a thermally melting synthetic resin. One end of the cylindrical filter element is connected to a respective through hole in a rigid support plate, and the opposite end is blocked.

Abstract: A composite material is provided which includes a discrete phase including grains made of a first substance; and a continuous phase including a thin coating film made of a second substance and formed on the surface of each of the grains. The thin coating film has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film. The porosity of the composite material is 5% or less.

Abstract: A magnetic material is provided which includes a discrete phase including grains made of a first substance which comprises a magnetic metal; and a continuous phase including a thin coating film made of a second substance which comprises a dielectric or insulating substance. The thin coating film is formed on the surface of the grains and has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film.

Abstract: A magnetic material is provided which includes a discrete phase including grains made of a first substance which comprises a magnetic metal; and a continuous phase including a thin coating film made of a second substance which comprises a dielectric or insulating substance. The thin coating film is formed on the surface of the grains and has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film.

Abstract: A polytetrafluoroethylene porous film, which is prepared by stretching a semisintered polytetrafluoroethylene material and heating the stretched material at a temperature higher than the melting point of sintered polytetrafluoroethylene, has an area ratio of fibrils to nodes of from 99:1 to 75:25, an average fibril diameter of from 0.05 to 0.2 .mu.m, a largest node area of not larger than 2 .mu.m.sup.2 and an average pore size of from 0.2 to 0.5 .mu.m and achieves low pressure loss.

Abstract: A process for producing a multilayer polytetrafluoroethylene porous membrane is disclosed, which process comprises at least two layers having different average pore diameters, the process comprising the steps of: filling the inside of a cylinder of an extruding mold distinctively with at least two kinds of polytetrafluoroethylene fine powders with each of which a liquid lubricant has been mixed; paste-extruding the powders to obtain a multilayer extrudate, which is then optionally rolled; removing the liquid lubricant from the multilayer extrudate or the rolled multilayer extrudate to obtain an unsintered multilayer structure; subsequently heating the unsintered multilayer structure at a temperature not lower than the melting point of sintered polytetrafluoroethylene to obtain a semisintered multilayer structure; and then stretching the semisintered multilayer structure at least monoaxially.

Abstract: A porous PTFE film having a thin thickness and good permeability is produced by coating an emulsion of polytetrafluoroethylene on a substrate surface, in particular, a porous polytetrafluoroethylene substrate which has not been heated at a melting point of unsintered polytetrafluoroethylene or higher, heating the coated substrate at a temperature not lower than a melting point of sintered polytetrafluoroethylene to semi-sinter polytetrafluoroethylene, optionally removing the semi-sintered polytetrafluoroethylene film from the substrate, and then stretching the semi-sintered film at least in one direction.

Abstract: A composite material is provided which includes a discrete phase including grains made of a first substance; and a continuous phase including a thin coating film made of a second substance and formed on the surface of each of the grains. The thin coating film has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film. The porosity of the composite material is 5% or less.

Abstract: An oxide superconductive material comprising constituent elements mainly composed of ABiCuO in which A comprises at least one element of alkaline earth metals, and having a C-plane orientation, and a method of orienting such superconductive materials by hot extrusion from a rectangular nozzle.

Abstract: A process for producing a multilayer polytetrafluoroethylene porous membrane comprising at least two layers having different average pore diameters is disclosed, the process comprising the steps of: filling the inside of a cylinder of an extruding mold distinctively with at least two kinds of polytetrafluoroethylene fine powders with each of which a liquid lubricant has been mixed; subsequently paste-extruding the powders to obtain a multilayer extrudate, which is then optionally rolled; and then stretching the extrudate or the rolled extrudate at least monoaxially after the liquid lubricant is removed therefrom or without removing the liquid lubricant.

Abstract: A magnetic head has substrate(s) having a thermal expansion coefficient nearly equal to that of a soft magnetic film formed thereon, and the substrate has a composition consisting of .alpha.-Fe.sub.2 O.sub.3, or a ceramic composition containing 57-96 mol % of MgO, 2-41 mol % of NiO and 2-41 mol % of TiO.sub.2, and the soft magnetic film is an amorphous alloy film.

Abstract: The present invention provides a process for producing powder of complex perovskite type compounds by using metal alkoxides. In the prior art, methods were known for synthesizing crystalline powder of simple perovskite type compounds such as BaTiO.sub.3. According to the conventional methods, however, when synthesizing a complex perovskite type compound having two atoms of different valences at the B site of perovskite structure by hydrolyzing metal alkoxides, there could be obtained only amorphous powder, and for crystallizing it, heating to a temperature of around 600.degree. to 800.degree. C. was necessary.According to the process of this invention, it is possible to synthesize the crystalline complex perovskite type compounds at a low temperature of around 100.degree. C., which is 500.degree. to 700.degree. C.

Abstract: Tape contact surface of a magnetic head is made of magnetic substance of multi-layered structure; interface insulation material for said multi layered structure and/or gap spacer material are made of oxides, complex oxides, nitrides and carbides of transition metal elements, IIa group elements of the periodic table and Zn; and accumulation of magnetic material from magnetic tape is prevented and output of magnetic head is stabilized.

Abstract: A method for producing crystalline complex perovskite compounds from starting compounds of at least one metal such as Ca, Ba or Sr, at least one metal such as Mg, Zn, Ni or Co and at least one metal such as Ta or Ni. The respective compounds are selected from oxides, hydroxides, hydrous oxides, and water-soluble organic compounds and inorganic salts of the respective metals. The water-soluble organic compounds and inorganic salts are capable of yielding metal oxides, hydroxides and hydrous oxides by hydrolysis. These starting compounds are heated at certain temperatures in an alkaline aqueous solution to obtain the perovskite compound at significantly low reaction temperatures of at least 95.degree. C. Prior to the heating, the starting compounds may be treated in the alkaline aqueous solution at temperatures lower than 95.degree. C. to form a uniformly mixed amorphous phase of the compounds and then heated.

Abstract: A PTC composition comprising at least one polymer, from 5% to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10.sup.2 [s/m] dispersed in said polymer, and from 0.2% to 20% by volume of thermally conductive particles having a room temperature electric conductivity of no more than 10.sup.-3 [s/m] and a thermal conductivity of at least 20 [w/m.multidot.k] dispersed in said polymer. A PTC device using such a PTC composition has a high ratio of peak resistance to room temperature resistance, and exhibits high safety.

Abstract: Electrostatic charge on a cassette or disc is grounded, when the latter is inserted into a player therefor through an opening formed in a front panel thereof, through a grounding path connecting a hinge pin of a flap covering the opening normally by a biasing spring associated therewith to a chassis of the player.

Abstract: A fluidity controlling agent for paints is provided which comprises a product obtained by reacting paratoluidine and hexamethylene diisocyanate at a particular equivalent ratio (NH.sub.2 NCO) and gives thixotropic properties to the paint without sagging at a large coating film thickness.

Abstract: Heavy duty pneumatic tires having lug grooves at a tire tread surface are disclosed, wherein a width of a tread portion from a tire equator to one of tread edges which tread portion is to be located on a wheel-mounted outer side is larger than that of the other tread portion from the equator to the other tread edge. When contours of the tread portions located on the opposite sides of the tire equator are approximated by two respective circular arcs, the radius of curvature of the wider tread portion is larger than that of the narrower tread portion. A depth of grooves at the shoulder portion on the wider tread portion which depth is expressed by a distance between the tread edge and the bottom of the lug grooves is made smaller than that of the narrower tread portion.