Abstract: Provided is a linear groove formation pattern with which both an effect of reducing the building factor and a high magnetic flux density can be obtained. In a grain-oriented electrical steel sheet having a plurality of linear grooves extending in a direction crossing a rolling direction of the steel sheet on a surface of the steel sheet, a surface of the steel sheet between the linear grooves has a recessed defect that is recessed from the surface, a volume fraction of the recessed defect in the steel sheet is 0.0025 vol % or more and 0.01 vol % or less of a steel sheet without the recessed defect, and discontinuous portions that disrupt the extension of the linear grooves are provided at a frequency of 30 or more and 200 or less per square meter of the steel sheet.

Abstract: A grain-oriented electrical steel sheet for a wound transformer core. The steel sheet having a sheet thickness t, where t and an iron loss deterioration ratio obtained by subjecting the steel sheet under elliptic magnetization satisfy the following relations: (i) when t?0.20 mm, the iron loss deterioration ratio is 60% or less; (ii) when 0.20 mm<t<0.27 mm, the iron loss deterioration ratio is 55% or less; and (iii) when 0.27 mm?t, the iron loss deterioration ratio is 50% or less. The iron loss deterioration ratio is calculated from ((WA?WB)/WB)×100, where WA is iron loss under 50 Hz elliptic magnetization of 1.7 T in a rolling direction and 0.6 T in a direction orthogonal to the rolling direction, and WB is iron loss under 50 Hz alternating magnetization of 1.7 T in the rolling direction.

Abstract: Vibration of an iron core is reduced to reduce transformer noise. An iron core for a transformer comprises a plurality of grain-oriented electrical steel sheets stacked together, wherein at least one of the plurality of grain-oriented electrical steel sheets: (1) has a region in which closure domains are formed in a direction crossing a rolling direction and a region in which no closure domains are formed; (2) has an area ratio R0 of 0.10% to 3.0%, the area ratio R0 being defined as a ratio of S0 to S; and (3) has an area ratio R1a of 50% or more, the area ratio R1a being defined as a ratio of S1a to S1.

Abstract: Vibration of an iron core is reduced to reduce transformer noise. An iron core for a transformer comprises a plurality of grain-oriented electrical steel sheets stacked together, wherein at least one of the plurality of grain-oriented electrical steel sheets: (1) has a region in which closure domains are formed in a direction crossing a rolling direction and a region in which no closure domains are formed; and (2) has an area ratio R of 0.10% to 30%, the area ratio R being an area ratio, to the whole grain-oriented electrical steel sheet, of a region in which a shrinkage amount at a maximum displacement point when excited in the rolling direction at a maximum magnetic flux density of 1.7 T and a frequency of 50 Hz is at least 2×10?7 less than a shrinkage amount in the region in which no closure domains are formed.

Abstract: A distance measurement device includes: a mirror disposed so as to be tilted relative to a rotation center axis; a drive unit configured to rotate the mirror about the rotation center axis; a photodetector configured to detect reflected light, of laser light, reflected in a distance measurement region; and a condensing lens disposed on the rotation center axis and configured to condense the reflected light reflected by the mirror, on the photodetector. The mirror has a shape elongated in one direction and is disposed such that a short axis thereof is tilted relative to the rotation center axis in a direction parallel to a plane including the rotation center axis. A width in a short-axis direction of the mirror is smaller than a width of a lens portion of the condensing lens as viewed in a direction parallel to the rotation center axis.

Abstract: Provided is a wound core having a flat portion and corner portions adjacent to the flat portion, the flat portion including a lap portion, the corner portions including bent portions. A non-heat-resistant magnetic domain refined material is used for at least a part of the materials forming the wound core. Closure domains are formed in the non-heat-resistant magnetic domain refined material so as to extend in a direction intersecting a longitudinal direction of the non-heat-resistant magnetic domain refined material, an area of each of the closure domains in a cross section that is taken in the longitudinal direction being more than 7500 ?m2. In the lap portion, the ratio of the number of lap joint portions having a lap length of from 3.0 mm to 30 mm to the total number of lap joint portions is 50% or more.

Abstract: Provided is a method for producing a sliding member formed by impregnating a porous base member made of a bronze-based alloy with a resin material, the sliding member including a sliding surface where both the porous base member and the resin material are exposed, the method including: a step of preparing a back metal layer; a porous base member formation step of forming the porous base member by depositing particles of the bronze-based alloy on a surface of the back metal layer and sintering the particles; an impregnation step of impregnating the porous base member with the resin material; a deformation step of deforming an end edge of the back metal layer in a direction away from the sliding surface; and a cutting step of cutting the porous base member impregnated with the resin material to form the sliding surface.

Abstract: To reduce variations in iron loss among materials subjected to magnetic domain refining by electron beam irradiation and to stably obtain good iron loss properties, disclosed is a method of producing a grain-oriented electrical steel sheet including performing magnetic domain refining treatment by irradiating with an electron beam, in a pressure reduced area, a surface of a grain-oriented electrical steel sheet after subjection to final annealing, the method further including: before the irradiating with the electron beam, delivering the grain-oriented electrical steel sheet wound in a coil shape and heating the delivered grain-oriented electrical steel sheet to 50° C. or higher; and then cooling the grain-oriented electrical steel sheet such that the grain-oriented electrical steel sheet has a temperature of lower than 50° C. at the time of entering the pressure reduced area.

Abstract: A nitriding apparatus for manufacturing a grain-oriented electrical steel sheet is provided. The nitriding apparatus includes: a nitriding gas supply pipe for introducing gas including at least ammonia or nitrogen; and a nitriding treatment portion for successively performing high-temperature nitriding and low-temperature nitriding in nitriding treatment. The nitriding treatment portion includes a high-temperature treatment portion for performing the high-temperature nitriding and a low-temperature treatment portion for performing the low-temperature nitriding, and the nitriding gas supply pipe to the high-temperature treatment portion includes a cooling device.

Abstract: Provided is a grain-oriented electrical steel sheet which has been subjected to heat-resistant magnetic domain refining treatment and can effectively suppress carburizing and nitriding during stress relief annealing. The grain-oriented electrical steel sheet has a plurality of grooves on one side that extend linearly across the rolling direction and are lined up at intervals in the rolling direction, and has at least a forsterite film on a surface of the steel sheet, where an average thickness of the forsterite film formed on the floor of the grooves is 0.45 ?m or more, and a standard deviation a of the thickness is 0.34 ?m or less.

Abstract: Provided is a linear groove formation pattern with which both an effect of reducing the building factor and a high magnetic flux density can be obtained. In a grain-oriented electrical steel sheet having a plurality of linear grooves extending in a direction crossing a rolling direction of the steel sheet on a surface of the steel sheet, a surface of the steel sheet between the linear grooves has a recessed defect that is recessed from the surface, a volume fraction of the recessed defect in the steel sheet is 0.0025 vol % or more and 0.01 vol % or less of a steel sheet without the recessed defect, and discontinuous portions that disrupt the extension of the linear grooves are provided at a frequency of 30 or more and 200 or less per square meter of the steel sheet.

Abstract: Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

Abstract: Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.

Abstract: A grain-oriented electrical steel sheet for a stacked transformer core. The steel sheet having a sheet thickness t, where t and an iron loss deterioration ratio obtained by subjecting the steel sheet under elliptic magnetization satisfy the following relations: (i) when t?0.20 mm, the iron loss deterioration ratio is 85% or less; (ii) when 0.20 mm<t<0.27 mm, the iron loss deterioration ratio is 80% or less; and (iii) when 0.27 mm?t, the iron loss deterioration ratio is 75% or less. The iron loss deterioration ratio is calculated from ((WA?WB)/WB)×100, where WA is iron loss under 50 Hz elliptic magnetization of 1.7 T in a rolling direction and 1.0 T in a direction orthogonal to the rolling direction, and WB is iron loss under 50 Hz alternating magnetization of 1.7 T in the rolling direction.

Abstract: One aspect of the present disclosure relates to a method for manufacturing a spun yarn made of carbon nanotubes. The method includes: a spun yarn precursor ? production step of producing a spun yarn precursor ? by pulling a plurality of carbon nanotubes from a carbon nanotube forest and spinning the carbon nanotubes while applying a tension of 6 mN or less per centimeter of a width of the carbon nanotube forest to the carbon nanotubes; a spun yarn precursor ? production step of producing a spun yarn precursor ? by applying a higher tension than in the spun yarn precursor ? production step to the spun yarn precursor ? to densify the spun yarn precursor ?; and a spun yarn production step of producing the spun yarn by electrically heating the spun yarn precursor ? while applying a tension to the spun yarn precursor ?.

Abstract: Provided is a method for producing a sliding member formed by impregnating a porous base member made of a bronze-based alloy with a resin material, the sliding member including a sliding surface where both the porous base member and the resin material are exposed, the method including: a step of preparing a back metal layer; a porous base member formation step of forming the porous base member by depositing particles of the bronze-based alloy on a surface of the back metal layer and sintering the particles; an impregnation step of impregnating the porous base member with the resin material; a deformation step of deforming an end edge of the back metal layer in a direction away from the sliding surface; and a cutting step of cutting the porous base member impregnated with the resin material to form the sliding surface.

Abstract: The linear groove formation method includes a resist forming process of forming a coated resist on a surface of a steel sheet, a laser irradiating process of irradiating laser beams onto the steel sheet while repeating a laser scanning in a direction intersecting a rolling direction of the steel sheet cyclically in the rolling direction of the steel sheet to remove the coated resist in portions irradiated with the laser beams, and an etching process of forming linear grooves by etching portions of the steel sheet from which the coated resist is removed. In the laser irradiating process, the coated resist is removed by using two or more laser irradiating devices, with a certain irradiation energy, a certain beam diameter in a direction perpendicular to a laser scanning direction, and a certain incidence angle with respect to the surface of the steel sheet.

Abstract: A grain-oriented electrical steel sheet having linear grooves formed cyclically in a rolling direction of the grain-oriented electrical steel sheet such that a longitudinal direction of the linear grooves intersects the rolling direction, in which each of the linear grooves has a discontinuous portion of center lines where center lines of the groove are shifted in a groove width direction, and when a width of the linear groove is defined as a and a distance in the groove width direction between the center lines in the discontinuous portion of center lines is defined as b, a and b satisfy relational expression (1) below. 0.05?b/a?0.

Abstract: Iron core vibration and transformer noise can be reduced by using, as a transformer iron core, an iron core formed by a stack of at least two types of grain-oriented electrical steel sheets that differ in magnetostriction by 2×10?7 or more when excited from 0 T to 1.7 T.

Abstract: A linear groove formation method including forming a coated resist on a surface of a steel sheet, irradiating two or more laser beams onto the surface of the steel sheet while scanning the laser beams in a direction intersecting the rolling direction of the steel sheet cyclically in a rolling direction of the steel sheet, and forming linear grooves by etching portions of the steel sheet. In the laser irradiating process, the coated resist is removed continuously in a sheet transverse direction of the steel sheet by using the laser beams irradiated from respective ones of two or more laser irradiation devices arranged in the sheet transverse direction, and the laser beams are irradiated by shifting centers of two of the laser beams irradiated from two of the laser two of the laser irradiation devices adjacent to each other in the sheet transverse direction.