Abstract: In a microwave apparatus with an air-tight window plate, first and second coaxial waveguide assemblies are coupled to each other so that a coaxial waveguide is formed. The first and second inner conductor sections of the first and second assemblies have first and second metal blocks. The first metal block is fitted in the second metal block by a shinkage fit and the first outer conductor section of the first assembly is air-tightly welded to the second outer conductor section of the second assembly. An RF matching annular groove is defined between the first and second metal blocks.

Abstract: A magnetic recording medium comprises a light-shielding base in the form of a tape or sheet, and a magnetic layer composed of a magnetic powder of Co-coated .gamma.-Fe.sub.2 O.sub.3 dispersed in a resin binder and applied to the base. The powder has a specific surface area as determined by the BET adsorption method of at least 35 m.sup.2 /g. The light-shielding base portion contiguous to the magnetic layer is a transparent plastic film and the lower base portion is light-shielding. The light-shielding base has a light transmittance of 30% or below. The surface roughness of the base is, in terms of the center-line average surface roughness, 0.012 .mu.m or below.

Abstract: In a magnetic recording medium having a coating for magnetic recording formed on one side of the base and a back coating on the opposite side, the back coating consists of a nonmagnetic powder dispersed in a binder which is a combination of nitrocellulose, vinyl chloride-vinyl acetate copolymer, polyurethane, and an isocyanate compound.

Abstract: In a magnetic recording medium comprising a substrate and a magnetic layer formed thereon and composed of magnetic powder dispersed in a polymer binder, an improvement wherein said substrate is made of a polyethylene terephthalate having a refractive index of at least 1.499 in the direction of the thickness of the substrate.

Abstract: In a magnetic recording medium having a base, a coating for magnetic recording formed on one side of the base, and a back coating of a nonmagnetic powder dispersed in a binder containing a thermosetting resin and formed on the other side, the back coating contains a fatty acid and/or a fatty ester.

Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder and a fine titanium oxide powder having a particle diameter of at least 0.4.mu. and at least one other fine hard non-magnetic powder.

Abstract: A leader tape for magnetic recording tape, characterized in that a coating film, consisting of a polymeric binder, an inorganic powder having a Mohs' hardness of 5 or above in an amount of not more than 5% by weight on the basis of the binder weight, and an antistatic agent, is formed on a plastic base.

Abstract: The present invention provides a magnetic head of which magnetic core is composed of thin plates of a high magnetic permeability, each provided with an adhesive layer comprising a granular substance. In such structure, the stress relaxation achieved by said granular substance prevents the loss of effective magnetic permeability of said core, thereby improving the high frequency characteristics. Also the presence of said granular substance realizes a hardness in the vicinity of said adhesive higher than that of said thin plates of a high magnetic permeability, thereby improving the abrasion resistance of said core. Furthermore said adhesive layer is rendered satisfactorily thinner than said thin plate to prevent the loss of sensitivity.

Abstract: A lubricant sheet for a magnetic tape cassette characterized in that at least one side of a base incorporating an antistatic agent is provided with a release type silicone coating. This lubricant sheet combines the transparency derived from the use of the clear base and coating materials with the low friction characteristic and the antistatic property to suit the application as such for transparent tape cassette cases.

Abstract: The present invention provides a magnetic head of which magnetic core is composed of thin plates of a high magnetic permeability, each provided with an adhesive layer comprising a granular substance. In such structure, the stress relaxation achieved by said granular substance prevents the loss of effective magnetic permeability of said core, thereby improving the high frequency characteristics. Also the presence of said granular substance realizes a hardness in the vicinity of said adhesive higher than that of said thin plates of a high magnetic permeability, thereby improving the abrasion resistance of said core. Furthermore said adhesive layer is rendered satisfactorily thinner than said thin plate to prevent the loss of sensitivity.

Abstract: A magnetic tape cassette holding a wound magnetic tape comprising a transparent base film and a magnetic layer having a thickness of 5.mu. or less coated on the base film comprises a hole facing a light source for detecting the tape position, a hole facing a photosenser provided so as to form a light path passing to the hole for light source through which the magnetic tape is passed and a light-shielding filter having a light transmittance in the range between 0.5 and 10 percent placed in the light path.

Abstract: A magnetic recording tape comprises a polyethyleneterephthalate base film coated with a magnetic layer which has an index H given by the equation:1.5>19.00-0.406 d.sub.B -0.016 H-0.553 d.sub.Td.sub.T .ltoreq.18(.mu.m)wherein the reference d.sub.T (.mu.m) designates a total thickness of the magnetic recording tape; d.sub.B (.mu.m) designates a thickness of the base film and H designates a sum of numbers of interference rings (H.sub.1, H.sub.2, H.sub.3 . . . )per 1 mm.sup.2.

Abstract: A magnetic recording tape comprising a polyethylene terephthalate substrate and a magnetic material-containing layer closely adhered onto the substrate, which tape exhibits a reduced envelope variation. The polyethylene terephthalate substrate satisfies the formula:0.051H.sub.1 -0.59A+0.14 .DELTA.n+0.0015 (H.sub.2 -66.67).sup.2 +50.92.ltoreq.20wherein A is the average particle size of the polyethylene terephthalate crystals as determined from the half height width by X-ray diffractometry, and H.sub.1 is the average number of projections present in a unit area of 1 mm.sup.2 on the surface of the substrate, which projections have a height falling within the range of from 0.27 to 0.53 micron, H.sub.2 is the average number of projections similar to H.sub.1 above but having a height falling within the range of from 0.54 to 0.80 micron, rather than 0.27 to 0.53 micron, and .DELTA.n is the birefringence of the substrate.