Abstract: A welding apparatus includes a first electrode tip; a second electrode tip opposing the first electrode tip; and an electrically conductive part which is provided so as to be freely interposed between the second electrode tip and a work and ensures electrical conduction between the second electrode tip and the work when the electrically conductive part is interposed between the second electrode tip and the work, the electrically conductive part including an electrically conductive member one side of which opposes the work with a presence of a void space from the work when the electrically conductive member is interposed between the second electrode tip and the work, and against which the second electrode tip is abutted on another side thereof, and a pair of electrically conductive abutment members which are provided integrally with the electrically conductive member in such a manner as to extend toward the work, and distal ends of which are abutted against the work, a position of abutment of the electrically

Abstract: While steel sheets are positioned and held by a holding mechanism, a first laser beam is applied to a heating region of the steel sheet to space the steel sheet from the other steel sheet by a predetermined distance. A second laser beam is applied to a welding region to weld the steel sheets. An amount of heat applied by the first laser beam, a moving speed of the first laser beam, and a focused spot diameter of the first laser beam are set to keep the sheet irradiated with the first laser beam in an unmelted state and plastically deform the sheet.

Abstract: While steel sheets are positioned and held by a holding mechanism, a first laser beam is applied to a heating region of the steel sheet to space the steel sheet from the other steel sheet by a predetermined distance. A second laser beam is applied to a welding region to weld the steel sheets. An amount of heat applied by the first laser beam, a moving speed of the first laser beam, and a focused spot diameter of the first laser beam are set to keep the sheet irradiated with the first laser beam in an unmelted state and plastically deform the sheet.

Abstract: Electrodes are embedded respectively in a first die and a second die. A metal workpiece is placed in a cavity defined between the first die and the second die which mate with each other. Then, a molten metal is poured through a passage into the cavity. The molten metal is solidified into a casting, forming a contact region of the metal workpiece and the casting. Thereafter, an electric current is supplied from a power supply between the electrodes across the contact region. The supplied electric current breaks an oxide film that is present on the surface of the metal workpiece, and joins the metal workpiece and the casting in the contact region.

Abstract: While steel sheets are positioned and held by a holding mechanism, a first laser beam is applied to a heating region of the steel sheet to space the steel sheet from the other steel sheet by a predetermined distance. A second laser beam is applied to a welding region to weld the steel sheets. An amount of heat applied by the first laser beam, a moving speed of the first laser beam, and a focused spot diameter of the first laser beam are set to keep the sheet irradiated with the first laser beam in an unmelted state and plastically deform the sheet.

Abstract: A composite oxide catalyst represented by the general formula: Mo-V-P-X-Y (wherein X represents at least one element selected from the group consisting of Sb, Cu, Co, Bi and As; Y represents at least one element selected from the group consisting of K, Rb, Cs and Tl) and a method for preparing methacrylic acid through gas phase catalytic oxidation of methacrolein with molecular oxygen in the presence of the foregoing catalyst are herein disclosed. The catalyst exhibits excellent catalytic activity, selectivity to methacrylic acid, catalytic stability and lifetime.

Abstract: A method for preparing acrolein or methacrolein comprises subjecting propylene, secondary propanol, isobutylene or tertiary butanol to gas phase catalytic oxidation with molecular oxygen in the presence of a catalyst represented by the following general formula (I):Mo.sub.a Bi.sub.b Fe.sub.c X.sub.d Y.sub.O Z.sub.f O.sub.g (I)wherein X represents at least one element selected from the group consisting of Ni and Co; Y represents at least one element selected from the group consisting of K, Rb, Cs and Tl; and Z represents at least one element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Ce, Ti, Zr, Nb, Cr, W, Mn, Cu, Ag, Zn, Cd, B, Al, Si, Ge, Sn, Pb, P, As, Sb, S, Se and Te; a, b, c, d, e, f and g each represents an atomic ratio of the corresponding element and when a is assumed to be 12, b=0.1.about.10, c=0.1.about.20, d=2.about.20, e=0.01.about.2, f=0.about.

Abstract: The catalytic activity of a chromium oxide-based catalyst used in the production of chlorine by oxidation of hydrogen chloride gas with an oxygen-containing gas is regenerated by impregnating it with an aqueous solution of chromic acid anhydride or of a chromium salt and then calcining the catalyst at a temperature not higher than 800.degree. C.

Abstract: An excellent steam reforming catalyst for hydrocarbons is provided having at least one of nickel oxide, cobalt oxide and platinum group noble metals supported on a carrier consisting essentially of aluminum oxide Al.sub.2 O.sub.3 and a metal oxide expressed by MeO, comprising about 3-35 mols of metal oxide MeO to 100 mols of aluminum oxide Al.sub.2 O.sub.3 in the carrier, Me being at least one metal selected from the group consisting of calcium Ca, barium Ba and strontium Sr. The catalyst exhibits high activity, superior mechanical strength, good heat resistant property, splendid chemical stability, and remarkable thermal shock resistant property, retains a high specific surface area at high temperatures, and does not form detrimental nickel aluminate or cobalt aluminate in steam reforming reactions of hydrocarbons.A method of producing the catalyst is also provided.

Abstract: A ceramic honeycomb filter for purifying exhaust gases from combustion engines includes a ceramic honeycomb structure formed by extruding and having a number of through-passages alternately closed at their ends by ceramic closure members. The through-passages formed by partition walls for capturing fine particles in the exhaust gases accumulated on the partition walls. The ceramic honeycomb filter comprises porous ceramic layers provided on the partition walls over a distance of 1/10-8/10 of an effective length of the filter from outlet ends of said through-passages for the exhaust gases.

Abstract: Excellent heat resistant compositions suitable for catalyst carries or catalysts are provided, which retain specific surface area thereof at high temperatures of not less than about 1200.degree. C. far better than conventional most superior .gamma.-alumina.

Abstract: A ceramic honeycomb body has a plurality of through holes defined by partition walls so as to be separated from each other, and fins are integrally formed with selected partition walls so as to extend into the through holes surrounded by such selected partition walls, whereby the cross-sectional area of the through hole is selectively reduced by the fins thus provided.

Abstract: A heat resistant and thermal shock resistant ceramic honeycomb catalytic converter for purifying automotive exhaust gas and the like is constructed by arranging at least one ceramic honeycomb structural body, having a dimension of0.10.ltoreq.L/D.ltoreq.0.40wherein L and D are respectively a length and a diameter of the ceramic honeycomb structural body, upstream of and adjacent to another ceramic honeycomb structural body in a metal casing.