Abstract: Disclosed is a heat exchanger arranged such that a plurality of groups of cuttouts are formed on the surfaces of flat fins as between vertically adjacent heat transfer tubes by providing a plurality of cutouts, including two openings extending transverse to the direction of the air flow and two legs nonparallel with said direction of the air flow, on the front and reverse sides of the flat fins. This arrangement remarkably reduces the heat resistance between the air and the fin surfaces. Since the plurality of cutouts or the plurality of groups of cutouts are formed in the identical configuration, maintenance of a mold can be facilitated.

Abstract: Disclosed is a heat exchanger having a plurality of flat fins disposed in parallel at predetermined intervals and adapted such that the air flows therebetween and a plurality of heat-transfer tubes disposed to intersect at right angles with the plurality of fins and adapted such that a fluid flows therethrough. The heat-transfer tubes are arranged such that a line connecting the adjacent heat-transfer tubes in the longitudinal direction of the fin is perpendicular to the direction of the air flow. The projection area in the direction of the air flow of any of the heat-transfer tubes located on the upstream side with respect to the air flow partially overlaps the position of at least one of the heat-transfer tubes disposed on the downstream side thereof. The pitch of adjacent heat-transfer tubes is smaller in the direction perpendicular to the air flow than in the direction of the air flow. Such an arrangement excells in both the frosting characteristics and performance.

Abstract: A magnetic recording medium having good running stability and high electromagnetic characteristics which comprises a base film, a magnetic layer provided on one surface of the base film and a back coat layer provided on the other surface of the base film, said back coat layer comprising non-magnetic oxide particles at least one of complex oxide or oxide solid solutions of the SiO.sub.2 or TiO.sub.2 system.

Abstract: A heat exchanger is provided in an air conditioner, refrigerator or the like, and is provided for the indirect transmission and reception of heat between fluids. The heat exchanger comprises a plurality of flat plate fins which are arranged parallel to one another at predetermined intervals so as to allow air stream to flow therebetween, and a plurality of heat transfer tubes passing through the flat plate fins for allowing a fluid to flow therethrough. Each fin is provided with a number of groups of air vents arranged to cross the wake side of the air stream. Each of the air vents is defined by a slat having four sides in which two sides, facing the air stream, are opened and other two sides are provided with leg portions for connecting the slat with the fin. The leg portions are aligned with each other and are inclined with respect to the normal line of the leading edge of the fin.

Abstract: A method of manufacturing a fin-tube heat exchanger which includes a multiplicity of plate fins arranged in a plurality of rows disposed at a predetermined pitch in the direction of air flow, and a jointless refrigerant pipe extending through the plate fins in a zigzag manner. Pipe-receiving holes are formed in each plate fin in an offset manner relative to the center of the plate fin. The plate fins are then placed in fin-receiving grooves formed in a straight fin positioning fixture at predetermined spacings such that the same longitudinal ends of the plate fins of alternating rows appear on the same side of the fin positioning fixture and such that the pipe-receiving holes are linearly aligned. The refrigerant pipe is inserted into the pipe-receiving holes and is expanded to make tight and close contact with the plate fins.

Abstract: An improved magnetic recording medium suitable for high density recording is disclosed, which has a squareness ratio in the vertical direction of 0.6 or more and an orientation ratio (squareness ratio in the vertical direction/squareness ratio in the lengthwise direction) of 0.7 or more, prepared from acicular magnetic iron oxide particles having crystalline magnetic anisotropy and a ratio of Fe.sup.2+ /Fe.sup.3+ of 0.05 or less uniformly cobalt-doped, the particles having preferably a particle size of 0.3.mu. or less and an axial ratio of 6 to 10.

Abstract: A magnetic recording medium suitable for high-density recording, which comprises a magnetic layer containing uniaxial anisotropic, acicular iron oxide particles having a particle size of not more than 0.3.mu., with a surface layer containing a major amount of cobalt being formed on seeds of the magnetic particles, said magnetic recording medium having a residual magnetic flux density both in a vertical direction and in a horizontal or longitudinal direction of not less than 1000 gauss.

Abstract: A magnetic recording medium improved in lubricity and abrasion resistance, which comprises a base material and a magnetic layer provided thereon, said magnetic layer comprising magnetic particles and a binder, characterized in that said magnetic layer further comprises at least one silicone compound of the formula: ##STR1## wherein X is the same or different and --A--COOH, --A--OH, ##STR2## or --A--NH.sub.2 in which A is a divalent hydrocarbon group having not more than 26 carbon atoms, Y and Y' are each --X or --CH.sub.3, p is an integer of 0 to 1,000 and q is an integer of 1 to 500 but p+q is not more than 1,000 in an amount of 0.1 to 5% by weight based on the weight of the magnetic particles in the magnetic layer.