Abstract: A method of sealing a surface crack in a member is provided includes steps of irradiating a region of the member at which the crack is produced with a heating laser beam so as to heat the region to a temperature lower than a melting point of the member, and then irradiating a region of the member at which the crack is produced with a welding laser beam subsequent to irradiation of the heating laser beam so as to heat the region to a temperature higher than or equal to the melting point of the member, thereby sealing an opening of the surface crack of the member.

Abstract: There is provided an improved laser shock hardening method and apparatus which can eliminate spattering of a liquid and waving of the liquid surface upon laser irradiation, and can stably irradiate a workpiece with a laser beam. Thus, the present invention provides in a laser shock hardening method for carrying out surface processing of a workpiece in contact with a liquid by irradiating through the liquid the surface of the workpiece with a pulsed laser beam intermittently emitted from a laser irradiation device, the improvement comprising: providing a solid transparent to the wavelength of the laser, serving as an entrance window to the surface of the liquid; allowing the liquid to be present in the light path of the laser beam between the solid and the surface of the workpiece; and allowing the laser beam to enter through the solid and irradiating through the liquid the surface of the workpiece with the laser beam, thereby shock-hardening the surface of the workpiece.

Abstract: A laser maintenance apparatus including a laser system which includes an optical system for emitting, in a first irradiation condition, a generation laser beam for generating an ultrasonic wave in a portion of an object on which maintenance is to be performed, and including a laser source configured to generate and detect a detection laser beam which interacts with the ultrasonic wave generated by the laser light beam in the first condition. The laser maintenance apparatus also includes a light transmitting device for transmitting laser light emitted from the laser system, a laser irradiation device for irradiating laser light transmitted by the light transmitting device to the object portion, and a transporting/scanning mechanism for transporting the light transmitting device and the laser irradiation device to a portion near the object portion, and scanning over an arbitrary range at the object portion.

Abstract: There is provided a multi-layered thermally conductive sheet having superior thermal conductivity and flame retardancy as well as superior handleability and adhesion even without using any of a halogen-containing flame retardant, red phosphorous, and silicone resin. The sheet includes a first acrylic thermally conductive sheet layer, and a second acrylic thermally conductive sheet layer disposed on one or both surfaces of the first layer. The first layer has an Asker C hardness of 60 or more and is obtained by curing a composition containing a metal hydrate at a content of 10% by volume or more, and the second layer has an Asker C hardness of 50 or less and is obtained by curing a composition containing a metal hydrate at a content of 5% by volume or more. The first layer has half or less thickness with respect to thickness of the whole sheet.

Abstract: An additive for a printing ink comprising a wax of either an ethylene homopolymer or ethylene.C3-20 ?-olefin copolymer each has an intrinsic viscosity, weight-average molecular weight/number-average molecular weight ratio, z-average molecular weight/weight-average molecular weight ratio, density, penetration hardness, and acid value in specific ranges; a solvent dispersion obtained by dispersing the wax; and a printing ink containing the wax.

Abstract: Provided is an electronic device comprising a thermally conductive sheet including a methacrylic polymer, a thermally conductive filler containing aluminum hydroxide in an amount of at least 10% by volume of the thermally conductive sheet, a combination of a phenolic antioxidant and a sulfur based antioxidant in an amount sufficient to impart thermal stability to the thermally conductive sheet, and a heat radiator.

Abstract: A nuclear reactor vibration surveillance system has a first ultrasonic transducer for transmission, an ultrasonic transmitter, a second ultrasonic transducer for reception, an ultrasonic receiver, a signal processor, and a display unit. The first ultrasonic transducer for transmission is arranged on the outer surface of a reactor pressure vessel and is configured to convert a transmission signal into an ultrasonic pulse signal and allow the ultrasonic pulse to be transmitted to a reactor internal component. The second ultrasonic transducer for reception is arranged on the outer surface of the reactor pressure vessel and is configured to receive a reflected ultrasonic pulse reflected by the reactor internal component and convert the received reflected ultrasonic pulse into a reception signal.

Abstract: Provided is a method for producing a thermally conductive sheet, comprising shaping a thermally conductive precursor composition into a sheet, the thermally conductive precursor composition comprising a (meth)acrylic monomer or a polymerizable oligomer thereof, a photopolymerization initiator, and a thermally conductive filler present in an amount of 20 vol % or more based on the total volume of the thermally conductive composition obtained, and irradiating the front surface and the back surface of the sheet with ultraviolet radiation at different ultraviolet irradiation intensities, thereby curing the sheet and obtaining a thermally conductive sheet having a single-layer thermally conductive composition and having tackiness differing between the front surface and the back surface.

Abstract: There is provided a thermally conductive sheet containing: (A) a (meth)acrylic polymer, (B) a thermally conductive filler containing aluminum hydroxide, (C) a phenolic antioxidant, and (D) a sulfur based antioxidant. The thermally conductive sheet is a non-silicone (meth)acrylic polymer type thermally conductive sheet and has both high thermal conductivity and thermal stability.

Abstract: There is provided an improved laser shock hardening method and apparatus which can eliminate spattering of a liquid and waving of the liquid surface upon laser irradiation, and can stably irradiate a workpiece with a laser beam. Thus, the present invention provides in a laser shock hardening method for carrying out surface processing of a workpiece in contact with a liquid by irradiating through the liquid the surface of the workpiece with a pulsed laser beam intermittently emitted from a laser irradiation device, the improvement comprising: providing a solid transparent to the wavelength of the laser, serving as an entrance window to the surface of the liquid; allowing the liquid to be present in the light path of the laser beam between the solid and the surface of the workpiece; and allowing the laser beam to enter through the solid and irradiating through the liquid the surface of the workpiece with the laser beam, thereby shock-hardening the surface of the workpiece.

Abstract: There is provided a multi-layered thermally conductive sheet having superior thermal conductivity and flame retardancy as well as superior handleability and adhesion even without using any of a halogen-containing flame retardant, red phosphorous, and silicone resin. The sheet includes a first acrylic thermally conductive sheet layer, and a second acrylic thermally conductive sheet layer disposed on one or both surfaces of the first layer. The first layer has an Asker C hardness of 60 or more and is obtained by curing a composition containing a metal hydrate at a content of 10% by volume or more, and the second layer has an Asker C hardness of 50 or less and is obtained by curing a composition containing a metal hydrate at a content of 5% by volume or more. The first layer has half or less thickness with respect to thickness of the whole sheet.

Abstract: There is provided a thermally conductive sheet containing: a binder component, a modified liquid polyolefin, and at least one thermally conductive filler selected from the group consisting of metal oxide and metal hydroxide. The thermally conductive sheet can have good moldability, and the surface of the sheet is inhibited from being contaminated by bleeding or the like. Further, the sheet can have good flexibility maintained for a long period of time and is inhibited from deteriorating or emitting an offensive odor due to decomposed matter of an organic phosphorous compound even when an organic phosphorous compound is contained.

Abstract: A laser maintenance apparatus is provided with a laser system including a laser light source and an optical system and emitting a laser light, a light transmitting device for generating the laser light emitted from the laser system, and a laser irradiation device for irradiating the laser light generated by the light transmitting device to an object portion. The laser system includes an element for changing an irradiation condition of the laser light.

Abstract: An additive for a printing ink comprising a wax of either an ethylene homopolymer or ethylene•C3-20 ?-olefin copolymer each has an intrinsic viscosity, weight-average molecular weight/number-average molecular weight ratio, z-average molecular weight/weight-average molecular weight ratio, density, penetration hardness, and acid value in specific ranges; a solvent dispersion obtained by dispersing the wax; and a printing ink containing the wax.

Abstract: Disclosed is a polyethylene wax defined by the features (i) to (iv): (i) said polyethylene wax is an ethylene homopolymer or a copolymer of ethylene and an ?-olefin of 3 to 20 carbon atoms, (ii) a ratio (Mw/Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), as measured by GPC, is in the range of 1.7 to 4.0, (iii) the softening point is not higher than 125° C., and (iv) the penetration hardness is not more than 15 dmm. Also disclosed are a lost wax composition for precision casting, which comprises the polyethylene wax, and a method for forming a model for precision casting, which uses the lost wax composition for precision casting.

Abstract: A laser emitting head for irradiating a portion to be machined with laser beams outputted from a laser unit (624) incorporates an emitting head body having a light guide member (625) in the head for guiding the laser beams; a light converging lens (677) for converging the laser beams transmitted from the light guide member in the head; a reflecting mirror (678) for irradiating the portion to be machined with the converged laser beams; mirror rotating means (684) for holding the reflecting mirror to be rotative around the optical axis of the laser beam; distance-adjustment means (674) for adjusting the relative distance between the reflecting mirror and the converging lens; and moving means (665) for moving the reflecting mirror and the converging lens such that the relative distance is maintained so that the light guide member in the head. The converging lens and the reflecting mirror can be introduced/discharged with respect to a portion to be machined and formed in a narrow gap in an incore structure.

Abstract: A laser transmission system for transmitting laser beam to an optical fiber comprises a pulse laser oscillator unit, a beam guide unit having an optical condensing unit for condensing a pulse laser beam radiated from the pulse laser oscillator unit, an optical fiber unit for transmitting the pulse laser beam condensed by the optical fiber beam guide unit, and a device for reducing a coherence of the pulse laser beam provided for at least one of the pulse laser oscillator unit, the beam guide unit and the optical fiber unit. This coherence reducing device is for making substantially uniform distribution of laser beams at a beam entrance portion of the optical fiber unit and preventing the laser beams from focussing or converging on one point in the optical fiber unit.

Abstract: The present invention provides an underwater maintenance and repair technology of including a laser oscillator for generating a laser beam and a working head movably attached to the vicinity of a working target portion in the underwater and adapted to scan the laser beam to the working target portion, and further, independently fixing the working head to the vicinity of the working target portion, jointing an optical fiber cable to the working head by using a joint mechanism through a remote control operation, guiding a laser beam emitted from a laser oscillator via the optical fiber cable, and irradiating the laser beam from the working head to a surface of the working target portion while scanning it so as to achieve surface modification, surface working and decontamination.

Abstract: The present invention provides an underwater maintenance and repair technology of including a laser oscillator for generating a laser beam and a working head movably attached to the vicinity of a working target portion in the underwater and adapted to scan the laser beam to the working target portion, and further, independently fixing the working head to the vicinity of the working target portion, jointing an optical fiber cable to the working head by using a joint mechanism through a remote control operation, guiding a laser beam emitted from a laser oscillator via the optical fiber cable, and irradiating the laser beam from the working head to a surface of the working target portion while scanning it so as to achieve surface modification, surface working and decontamination.

Abstract: A laser maintaining and repairing apparatus including a laser oscillator 7, beam guiding apparatus 8 connected to guide a laser beam of the laser oscillator 7, and emitting head 12 for converging the laser beam from the beam guiding apparatus 8 and emitting the beam to a portion to be processed. The beam guiding apparatus 8 includes liquid-tight tubular beam guiding members 9a to 9h. The beam guiding members 9a to 9h are provided with reflecting members 13a, 13b and at least one of mechanisms 10a, 10b and 11a, 11b for providing horizontal turning, horizontal extending, vertical turning and vertical extending operations at the beam guiding members 9a to 9h. With the laser maintaining and repairing apparatus of the noted structure, a laser beam of high energy density can be utilized and processing by the laser beam can be facilitated or the applying range can be increased.