Abstract: In a method for high frequency pulse welding and an apparatus therefor, a highly directive arc can be obtained by eliminating the effect of the inductance of the welding cable, which tends to make the high frequency electromagnetic pinch force large. In a method and an apparatus for high frequency pulse arc welding which is performed by generating an arc between an inconsumable electrode or a consumable electrode arranged near a portion of a base metal to be welded and the base metal with main pulse current, when the main pulse current is shifted from ON to OFF, a reverse pulse current having a polarity opposite to the polarity of the main pulse is supplied between the electrode and the base metal to improve the stiffness (directivity) of the arc by making the rising and falling edges of the pulses steeper. A rail-car and a nuclear power plant obtained by the method are also provided.

Abstract: An underwater laser processing system has a laser torch; a laser torch driving mechanism for changing a laser emission position of the laser torch; and a chamber with one end opened to an external environment, which contains the laser torch; wherein a partitioning wall for preventing permeation of water is provided between a free end of the chamber and the laser torch. The system is used for detecting a sensitized portion and repairing it at one time using a sensitization detecting arrangement. Moreover, it is used for forming an alloying layer by melting a sprayed coating film, and for forming a new surface layer by emitting a laser beam through a solution containing a metal component.

Abstract: A submerged laser beam irradiation equipment provides a high quality submerged laser beam processing of a submerged workpiece using only a small amount of a gas. The submerged laser beam irradiation equipment has: a focus lens for focusing a laser beam; a mirror tube which houses the lens; a first nozzle operating to cover the front end of the mirror tube in an irradiating direction of the laser beam; a skirt portion provided at the front end of the first nozzle for preventing water intrusion thereinto; and a shutter mechanism operable to open and close and provided between said skirt portion and said mirror tube for preventing water intrusion into said mirror tube.

Abstract: A thin film magnetic head comprising a sintered ceramic substrate, an underlayer, a bottom magnetic core film, a magnetic gap film, an insulating film containing coil windings, a top magnetic core film, and a protective layer. The substrate and other films and layers form an air bearing surface. The under layer, the magnetic gap film and the protective layer comprise Al.sub.2 O.sub.3, and the bottom and the top magnetic core films comprise Ni--Fe alloy. This structure gives substantially the same etching rate, when the air bearing surface is polished using a working fluid of pH 6-8, for any of the substrate, the films comprising Al.sub.2 O.sub.3 and metal oxide described above, and the films of Ni--Fe alloy. Thus, steps (pole top recessions) on the air bearing surface can be made as small as 0.015 .mu.m or less. Accordingly, the magnetic head can be held in a stable attitude, thus obtaining good recording characteristics.

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 thin film magnetic head comprising a substrate on which are successively formed a base layer, a lower magnetic film, a gap layer, an insulator layer, a conductor coil, an upper magnetic film, and a first mask, is manufactured by a method in which one or more of a gas which can be expressed by the general formula of CnHxFy (where n.gtoreq.1, x+y=2n+2, x>0, y>0, and x.gtoreq.y); and a gas which can be expressed by the general formula of CnHxFy (where n.gtoreq.1, x+y=2n+2, x.gtoreq.0, y.gtoreq.0, and x<y) is used. The structure of the magnetic head thus obtained is such that, at a height near the interface between the mask and the upper magnetic film provided therebelow, the angle defined by the side edge surfaces of the mask and the above-mentioned interface ranges from 75.degree. to 90.degree..

Abstract: An electric power supply in pulse form is applied between a welding electrode and workpieces. The temperature of a molten pool is measured by a radiation-type thermometer when no power supply pulse is applied, and the welding condition is controlled in response to an output signal of the radiation-type thermometer.

Abstract: In a welding apparatus having a plurality of electrodes and adapted for carrying out welding operation on a workpiece by alternately supplying currents to the individual electrodes through switching elements, an apparatus and method of controlling the currents supplied to the electrodes, comprising selecting the values of the currents supplied to the individual electrodes depending on the material of the workpiece, and carrying out the welding operation on the workpiece by alternately supplying the currents of the selected values to the individual electrodes respectively through the switching elements. The method is featured by the fact that the ratio between the individual currents is selected under the condition that the sum of the values of all the currents is maintained at a predetermined value.

Abstract: A method for storing sheets of a photothermographic sheet material composed of a high molecular weight compound support and a sensitive emulsion comprising, as the indispendable constituents, an organic silver salt oxidizing agent, a reducing agent for silver ion, a photosensitive silver salt compound or its precursor, and a binder, characterized by inserting paper having smooth surfaces between every two sheets of said photothermographic sheet material. By this method, the photothermographic sheet material can be stored for a long period of time without deterioration of quality.