Hitachi, Ltd.

Shinji Sakata

Tasuku Shimizu

Makoto Hayashi

Kunio Enomoto

Masahiro Otaka

Hideo Miura

Asao Nishimura

Hiroo Masuda

Motoya Ito

Jun Murata

Noriaki Okamoto

Satoshi Kanno

Makoto Ogasawara

Ryoichi Kaneko

Koichi Kurosawa

Shigeo Hattori

Kazuo Takaku

Takashi Saito

Sadato Shimizu

Nobuo Shimizu

Kunio Hasegawa

Yasuhiko Otawara

Hideyo Saito

Yoshinori Karatsu

Hirotsugu Fujimoto

Tsukasa Ikegami

Naoaki Shibashita

Yasunobu Tanizaki

Kiyoshi Shimomura

Eiji Wakimoto

Hirakazu Yokota

Terunobu Koike

A semiconductor device includes a thermal oxide film for isolation, a semiconductor region that becomes an element forming region with the circumference thereof surrounded by the oxide film and diffused resistance layers in the semiconductor region and provides a structure for controlling resistance value variation of diffused resistors originated in a stress generated at time of forming the oxide film for isolation. A distance between an end portion on a longer side closest to a thermal oxide film of the diffused layer and an end of the thermal oxide film is apart from each other by a predetermined value determined by stress distribution in the semiconductor region or by at least 4 .mu.m or more, the longitudinal direction of the diffused layer portion formed from the end of the thermal oxide film over to a stress distribution (gradient) forming region in the semiconductor region is parallel to the forming direction of the stress gradient, and resistance value distribution is formed parallel to the stress gradient in the diffused layer formed from the end of the thermal oxide film over to the stress distribution forming region in the semiconductor region.

Semiconductor device having circuit element in stress gradient region by

A nondestructive inspecting apparatus is arranged to have an exciting magnet for applying an ac magnetic field to a sample and a SQUID for converting change of a magnetic characteristic of the sample occurring when the ac magnetic field is applied to the sample into an electric signal. The exciting magnet is a cancelled coil assembly composed of plural coils having respective polarities.

Apparatus with cancel coil assembly for cancelling a field parallel to

A method of maintaining the housing of a reactor pressure vessel having: a reactor pressure vessel into which cooling water is introduced; a cylindrical housing which penetrates an end bracket of the reactor pressure vessel; and a circumferential weld for securing the intermediate portion of the housing to the reactor pressure vessel by welding, the method of maintaining a housing of a reactor pressure vessel comprising the steps of: remaining the cooling water in the reactor pressure vessel; preventing leakage of the cooling water in the reactor pressure vessel through the housing by sealing the housing; making the inside portion of the housing lower than the seal to be a hollow space of a gas atmosphere; heating a heat affected zone due to welding by using a heating device inserted into the hollow space from a lower portion so as to compressive-yield the inner surface of the housing in the heat affected portion upper than the circumferential weld and tensile-yield the outer surface; and cooling heated portion inside of the housing, which has been yielded, so as to tensile-yield the inner surface of the housing by using a cooling device inserted into the housing from a lower portion, whereby compressive stress is allowed to remain in the tensile-yielded portion.

Method of maintaining housing of reactor pressure vessel and heat

A method and apparatus for inspecting the change in a water quality in terms of the change in a corrosion rate by detecting the capacity change between opposed electrodes due to the corrosion of electrode surfaces. As a result, the water quality can be continuously monitored over a long time while leaving the electrodes in the water to be inspected. Thus, the method and apparatus are suited for controlling the water quality especially in an atomic reactor vessel.

Water quality inspection method and apparatus therefor

A method for improving residual stress in a circumferential weld zone of a piping and the like which includes preventing deformation of the weld zone, and causing a local expansion or contraction of a portion of the piping axially spaced from the weld zone thereby effecting a plastic working so as to increase or decrease the diameter of piping. The method can effectively be applied to apparatus and pipe system which are used in a corrosive environment and under action of a static or dynamic outer load.

Method of improving residual stress in circumferential weld zone

A method system for assessing the safety of a rotor of a shrinkage fitted type wherein an opening displacement of a crack is determined an elastic-plastic fracture method and a reduction in shrinkage fitting force is calculated based on the crack opening displacement. The safety of the rotor is assessed based on the reduction in shrinkage fitting force caused to occur by the opening of the crack.

Method of and system for assessing the safety of shrinkage fitted type

The invention scans potential measurement terminals on the surface of a structural member to measure a potential distribution on the surface, detects the direction of a crack from the potential distribution and determining a detailed potential distribution in the direction of the crack thus detected. This potential distribution is compared with master curves of the potential distributions of cracks of various shapes, that have been obtained by analysis in advance, in order to detect the shape of the crack. The present invention can detect accurately a crack shape.

Method and apparatus for detecting cracks

A method of subjecting a welded structure to heat treatment in which a tensile yield is produced on an inner surface of the welded structure and a compressive yield is produced on an outer surface of the welded structure by the steps of placing a cooling medium in the interior of the welded structure and heating the outer surface of the welded structure to cause a difference in temperature to exist between the inner surface and other surface of the welded structure. The method further includes the step of locally heating a weld by means of a heating member to improve residual stress in a localized area of the weld and repeating the improvement of the residual stress regarding another localized area of the weld.

Method of subjecting welded structure to heat treatment

The X-ray diffraction apparatus of the invention includes means capable of detecting the position and intensity distribution of the diffracted X-ray with respect to a thin bundle X-ray and means for moving the former means to a position at which the former means is capable of detecting the diffracted X-ray, and makes it possible to reliably and easily carry out rough detection of the position of the diffracted X-ray and fine detection of the intensity distribution of the diffracted X-ray without increasing the size of the diffracted X-ray detecting means.

X-Ray diffraction apparatus

A method of determining fatigue life of metals that are subject to the cyclic load. A metal that exhibits a half-value width that varies depending upon the degree of deformation by fatigue is melt-adhered onto a recessed portion formed in a metal of which the life is to be determined. The two metals are subjected to the cyclic load simultaneously. Then, the melt-adhered metal is irradiated with an X-ray, and a half-value width of an S-N curve of the resulting diffracted X-ray is measured, thereby to determine the fatigue life of the metal of which the life is to be estimated. The method is effective for accurately determining the life even for the metals which exhibit half-value widths that change very little depending upon the degree of deformation by fatigue.

Method of determining fatigue life of metals

A welding method of a turbine diaphragm for joining a spacer having a plurality of nozzle blades to outer and inner wheels. The spacer and the outer or inner wheel are welded from both sides. At first or inlet side of the diaphragm where a motive fluid flows into the diaphragm, the spacer and the outer and inner wheel are welded so that weld depth from the first side will be at most 0.5 L, wherein L is a distance between the first side and the top of the nozzle blade. At the second or outlet side of the diaphragm, from which the motive fluid exits, the spacer and the outer and inner wheels are weld so that a welded depth from the second side will be at least 0.3 C, wherein C is height of the nozzle blades.

Welding method of turbine diaphragm

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Katsuta, Japan

Shinji Sakata