Abstract: An electric motor control device such that a rotation angle correction value used in a phase correction of an angle sensor rotation angle signal can be calculated with high accuracy is obtained.

Abstract: A synchronous machine drive control device such that a rotation angle correction amount can be detected even when a synchronous machine is rotating at high speed, and the rotation angle correction amount can be detected over a wide range, is obtained. A rotation angle correction amount calculation unit that calculates a correction amount of a rotation angle of a synchronous machine is included in an inverter control device, and the correction amount of the rotation angle is calculated based on a current detected by a current sensor by a three-phase short circuit being implemented in a state wherein the synchronous machine is rotating.

Abstract: In a control device for an electric motor (101), a three-phase/two-phase conversion section (203) outputs N d-axis current values and N q-axis current values in each measurement period that is 1/N of a carrier period. An average value calculation section (204) calculates average values of those values. A difference calculation section (205) calculates a difference between a k-th d-axis current value and the average value of the d-axis current values as a d-axis current difference, and calculates a difference between a k-th q-axis current value and the average value of the q-axis current values as a q-axis current difference. A filtering section (206) performs low-pass filtering on each difference, and outputs d-axis and q-axis current correction values. A correction calculation section (207) performs a linear operation of each k-th current value and the corresponding current correction value, and outputs the corrected current values.

Abstract: A metal member includes a first plate, and a second plate abutting against and welded to the first plate in at least one butt portion. In the butt portion, a length from a first end to a second end of a welding boundary line between the first plate and the second plate is longer than a length of a straight line connecting the first end to the second end of the welding boundary line.

Abstract: In a control device for an electric motor (101), a three-phase/two-phase conversion section (203) outputs N d-axis current values and N q-axis current values in each measurement period that is 1/N of a carrier period. An average value calculation section (204) calculates average values of those values. A difference calculation section (205) calculates a difference between a k-th d-axis current value and the average value of the d-axis current values as a d-axis current difference, and calculates a difference between a k-th q-axis current value and the average value of the q-axis current values as a q-axis current difference. A filtering section (206) performs low-pass filtering on each difference, and outputs d-axis and q-axis current correction values. A correction calculation section (207) performs a linear operation of each k-th current value and the corresponding current correction value, and outputs the corrected current values.

Abstract: Provided are a plasma-MIG welding method and a welding torch that are capable of reducing spatter amount without relying on control of a MIG welding power supply. The plasma-MIG welding method employs a plasma-MIG welding device configured from: a plasma torch section that includes a plasma nozzle and a plasma electrode; and an MIG torch that includes an MIG tip and a welding wire. The plasma torch section and the MIG torch are arranged so as to face in different directions at a predetermined distance from each other. The plasma-MIG welding method is characterized in that a plasma arc is made to locally overlap with a tip end portion of the welding wire, and in a state in which melting of the welding wire is promoted, MIG welding is carried out without short-circuiting between a workpiece and a tip end of the welding wire which is a consumable electrode.

Abstract: A plasma welding torch that can be reduced in size more than in conventional cases. When an inert gas G such as argon gas is supplied to an outer circumferential space around a non-consumable electrode 13, a portion of the inert gas G is used as plasma gas GP that forms a plasma arc PA between the non-consumable electrode 13 and a base material 2 via a plasma orifice 51. A plasma welding torch 1 moves, maintaining this state, in the direction of the arrow shown in FIG. 4. Meanwhile, a portion of the inert gas G supplied to a gas flowing part 21 is not used as the plasma gas GP but is used as shielding gas GS and is ejected onto the base material 2 ahead in the welding direction via a shielding orifice 52. The welding on the base material 2 is performed in a state where the plasma arc PA and the base material 2 are shielded from the air by this shielding gas.

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: A plasma welding torch that can be reduced in size more than in conventional cases. When an inert gas G such as argon gas is supplied to an outer circumferential space around a non-consumable electrode 13, a portion of the inert gas G is used as plasma gas GP that forms a plasma arc PA between the non-consumable electrode 13 and a base material 2 via a plasma orifice 51. A plasma welding torch 1 moves, maintaining this state, in the direction of the arrow shown in FIG. 4. Meanwhile, a portion of the inert gas G supplied to a gas flowing part 21 is not used as the plasma gas GP but is used as shielding gas GS and is ejected onto the base material 2 ahead in the welding direction via a shielding orifice 52. The welding on the base material 2 is performed in a state where the plasma arc PA and the base material 2 are shielded from the air by this shielding gas.

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.