Abstract: Reduction of air resistance which acts on the conventional motor-driven blower is limited because crushed protrusions are formed on the surface of the plate of the impeller of the conventional motor-driven blower, and this air resistance is a significant impediment to an increase of the operating speed of the motor-driven blower. Thus, an impeller is provided which comprises a front plate having a suction opening, a back plate disposed opposite to the front plate, and a plurality of blades disposed between the front plate and the back plate. At least either the front plate or the back plate is formed integrally with the blades.

Abstract: Disclosed is a friction stir welding technique which avoids occurrence of a dent, in a joining region, extending to a level beneath the joined surfaces. At end portions of the frame members to be joined, at the joining region, thickened parts which project toward the rotary body joining tool are provided. Two adjoining thickened parts, of adjacent members to be joined, can form a trapezoid shape. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion. The rotary body joining tool is inserted in the thickened parts. In a state where the rotary body joining tool has been inserted small-diameter tip end first, to a level where the larger diameter portion of the rotary body joining tool overlaps the thickened part but does not extend below the upper surface of the non-thickened surfaces of the members joined, the rotary body is rotated and moved along the joining region. Even when a gap exists between two thickened parts, a desirable joining can be carried out.

Abstract: A neutron-irradiated structural material having a defect in a nuclear reactor internals is repaired by covering the structural material to be repaired with a plate to cover over a portion thereof having the defect, and then welding the plate and the structural material by locally applying pressure on the surface of the plate and adding energy to the portion to which the pressure is applied thereby to generate thermal energy in the contact surfaces between the plate and the structural material.

Abstract: A high reliability electric power control semiconductor device with a prolonged product lifetime has been provided by successfully suppressing the metal support plate or the metal heat dissipation plate from warping due to the thermal stress during bonding so as to prevent the occurrences of cracks and gaps in the brazing fillers in the bonded layers between the metal heat dissipation plate or the metal support plate and the insulation plate in the semiconductor device comprising the semiconductor elements, metal heat dissipation plate, thermal stress buffer, insulation plate, and the metal support plate, wherein at least one of the metal heat dissipation plate and the metal support plate comprises a copper alloy of which a softening temperature at which a hot hardness of which becomes 1/2 of the hardness at the room temperature is 350.degree. C. or more.

Abstract: The features of the present invention are 1) to apply metallization on the bonding surface of a piezoelectric ceramic with a metal likely to react with the piezoelectric ceramic material, 2) when the piezoelectric ceramic material is soldered on the bonding surface, to apply metallization with a metal likely to react with the solder material, 3) to provide between the metallizing layers formed in 1) and 2) a metallizing layer including metal which prevents reaction between the metals and their diffusion, 4) to use a mounting member for the piezoelectric ceramic which has substantially the same thermal expansion coefficient as the piezoelectric ceramic in non-polarization condition and 5) to solder in the non-polarization condition and thereafter to polarize.

Abstract: The present invention provides a method for joining of high-temperature oxide superconductors per se or a high-temperature oxide superconductor and other conductive material through a very simple process. According to this method, the joining is carried out by using an alloy comprising 0.1%-90% by weight of at least one divalent metallic element and the balance as a brazing material and heating and melting the brazing material. The resulting joined body has a joint low in resistance. The divalent metallic element of the alloy is preferably an element of Group IIA or IIB of the Periodic Table or a transition metal.

Abstract: The nuclear fusion reactor of the present invention presents a new vacuum vessel for enclosing plasma particles where a reactor wall exposed to the above plasma particles has a piled structure. A plurality of heat-resisting ceramic tiles are metallurgically bonded to a metal-base body having a cooling means through a brazing material. The ceramic tiles are preferably composed of sintered silicon carbide of high density and containing a little beryllium oxide between the boundaries of crystal grains.

Abstract: A carbon film is formed on a ceramic element, or a metal film is formed on the carbon film, and subsequently the ceramic element is bonded to another ceramic or metal element, thereby forming a composite article. The composite article has a high bonding strength and is hardly fractured at joint. Ceramic articles having a surface coating of a hard carbon film or a hard carbon film containing metal grains can also be formed by this process.

Abstract: A method for welding dissimilar metals, wherein the end of one of said dissimilar metals is welded to a metal plate by using a filler metal, the material of said metal plate being the same as that of another of said dissimilar metals; and electron beam welding is applied along the interface formed between such a joint surface of said metal plate, which does not include the aforesaid welded portion, and the joint surface of another of said dissimilar metals.

Abstract: A method for welding dissimilar metals, wherein a filler metal is deposited on one end of the aforesaid dissimilar metals to be jointed, said filler metal being of the same material as that of another of said dissimilar metals; the outer surface of the weld metal thus deposited is machined to provide a joint surface adapted for welding; and an electron beam welding is applied along the interface formed between said joint surface of said weld metal thus deposited and the joint surface of another of said dissimilar metals.