Abstract: According to one embodiment, a sliding bearing unit includes a stationary shaft including a first radial bearing surface, a rotor, and a lubricant. The rotor includes a first cylinder and a second cylinder. The second cylinder includes a second radial bearing surface and is restricted in operation so that it does not rotate relative to the first cylinder. The lubricant, together with the first radial bearing surface and the second radial bearing surface, forms a dynamic pressure radial sliding bearing.

Abstract: A welding apparatus according to one embodiment includes an irradiation device and nozzle. The irradiation device irradiates a surface of an object with an energy beam. The nozzle is provided with a first channel through which a shield gas flows and a second channel apart from the first channel and through which a gas flows, and the nozzle moves in an irradiation direction. The nozzle includes an end facing the surface and an outer face connected to the end and located in the irradiation direction with respect to the first channel. The end is provided with a first opening that communicates with the first channel and allows discharge of the shield gas toward the surface. The outer face is provided with a second opening that communicates with the second channel and allows the gas to be discharged away from the outer face in the irradiation direction.

Abstract: A welding apparatus according to one embodiment includes an irradiation device and nozzle. The irradiation device irradiates a surface of an object with an energy beam. The nozzle is provided with a first channel through which a shield gas flows and a second channel apart from the first channel and through which a gas flows, and the nozzle moves in an irradiation direction. The nozzle includes an end facing the surface and an outer face connected to the end and located in the irradiation direction with respect to the first channel. The end is provided with a first opening that communicates with the first channel and allows discharge of the shield gas toward the surface. The outer face is provided with a second opening that communicates with the second channel and allows the gas to be discharged away from the outer face in the irradiation direction.

Abstract: According to one embodiment, an X-ray tube assembly includes a housing, an X-ray tube, a coolant to which at least a part of heat generated by the X-ray tube is transferred, a circulation channel through which the coolant is circulated, a circulation pump, a radiator, an air filter and a fan unit. The air filter is formed of a three-dimensional nonwoven fabric that is formed of irregularly tangled resin fibers and provides a three-dimensional structure having a spatial volume ratio of not less than 93%. The air filter permits air to pass therethrough to eliminate dust from the air.

Abstract: According to one embodiment, an X-ray tube assembly includes a housing, an X-ray tube, a coolant to which at least a part of heat generated by the X-ray tube is transferred, a circulation channel through which the coolant is circulated, a circulation pump, a radiator, an air filter and a fan unit. The air filter is formed of a three-dimensional nonwoven fabric that is formed of irregularly tangled resin fibers and provides a three-dimensional structure having a spatial volume ratio of not less than 93%. The air filter permits air to pass therethrough to eliminate dust from the air.

Abstract: A diffraction optical element is provided to reduce harmful lights and also suppress deterioration in the optical characteristics of the element. The diffraction optical element 22 is formed with a plurality of diffraction gratings 17?, 18?, 19? and 20?. From these diffraction gratings, there are selected the diffraction gratings 18?, 19? and 20? whose groove apex angles are less than a predetermined angle. The diffraction gratings 18?, 19? and 20? has chamfer surfaces 18c?, 19c? and 20c? formed on the lower side of respective slanted surfaces 18a?, 19a? and 20a?. The chamfer surfaces 18c?, 19c? and 20c? are slanted to the slanted surfaces 18a?, 19a? and 20a?, respectively.

Abstract: The angle of each collimator plate with respect to an X-ray focal point is determined by fitting the collimator plate in grooves formed in upper and lower supports each having an integral structure. In addition, the warpage of each collimator plate is corrected and its flatness is maintained by fitting the periphery of the collimator plate which is on the X-ray detector side in a corresponding groove of an abutment plate provided on the X-ray detection surface side of the upper and lower supports. Furthermore, each collimator plate is supported by the corresponding grooves of the upper and lower supports and the corresponding groove of the abutment plate at least three sides.

Abstract: The angle of each collimator plate with respect to an X ray focal point is determined by fitting the collimator plate in grooves formed in upper and lower supports each having an integral structure. In addition, the warpage of each collimator plate is corrected and its flatness is maintained by fitting the periphery of the collimator plate which is on the X ray detector side in a corresponding groove of an abutment plate provided on the X ray detection surface side of the upper and lower supports. Furthermore, each collimator plate is supported by the corresponding grooves of the upper and lower supports and the corresponding groove of the abutment plate on at least three sides.

Abstract: A diffraction optical element is provided to reduce harmful lights and also suppress deterioration in the optical characteristics of the element. The diffraction optical element 22 is formed with a plurality of diffraction gratings 17?, 18?, 19? and 20?. From these diffraction gratings, there are selected the diffraction gratings 18?, 19? and 20? whose groove apex angles are less than a predetermined angle. The diffraction gratings 18?, 19? and 20? has chamfer surfaces 18c?, 19c? and 20c? formed on the lower side of respective slanted surfaces 18a?, 19a? and 20a?. The chamfer surfaces 18c?, 19c? and 20c? are slanted to the slanted surfaces 18a?, 19a? and 20a?, respectively.

Abstract: The angle of each collimator plate with respect to an X-ray focal point is determined by fitting the collimator plate in grooves formed in upper and lower supports each having an integral structure. In addition, the warpage of each collimator plate is corrected and its flatness is maintained by fitting the periphery of the collimator plate which is on the X-ray detector side in a corresponding groove of an abutment plate provided on the X-ray detection surface side of the upper and lower supports. Furthermore, each collimator plate is supported by the corresponding grooves of the upper and lower supports and the corresponding groove of the abutment plate at at least three sides.

Abstract: A detector unit for detecting X rays passed through a collimator having a plurality of collimator single plates, includes a substrate attached to a collimator support for supporting the collimator, a photodetecting device array including photodetecting devices mounted on the substrate, a scintillator block arranged corresponding to the photodetecting device array and provided on the photodetecting device array to convert the X rays into light, and an engaging component having an engaging portion provided on the collimator single plate side of the substrate, and engaged with the collimator single plate to regulate a position of the photodetecting device array or the scintillator block in a channel direction with respect to the collimator single plate.

Abstract: An X-ray tube includes a substantially cylindrical rotor having an anode target fixed thereto, a substantially columnar stationary shaft coaxially arranged inside the rotor with a bearing gap, a dynamic slide bearing having helical grooves and formed between the rotor and the stationary shaft, and a metal lubricant supplied to the grooves and to the gap. An axial bore is formed in the shaft to extend in the longitudinal direction of the shaft, and an insertion rod is inserted into the axial bore such that a space extending in the longitudinal direction of the shaft is formed between an inner circumferential surface of the axial bore and an outer circumferential surface of the insertion rod. The space acts as at least one lubricant reservoir that is configured to store the metal lubricant.

Abstract: A detector unit for detecting X rays passed through a collimator having a plurality of collimator single plates, includes a substrate attached to a collimator support for supporting the collimator, a photodetecting device array including photodetecting devices mounted on the substrate, a scintillator block arranged corresponding to the photodetecting device array and provided on the photodetecting device array to convert the X rays into light, and an engaging component having an engaging portion provided on the collimator single plate side of the substrate, and engaged with the collimator single plate to regulate a position of the photodetecting device array or the scintillator block in a channel direction with respect to the collimator single plate.

Abstract: An X-ray tube comprises a substantially cylindrical rotor having an anode target fixed thereto, a substantially columnar stationary shaft coaxially arranged inside the rotor with a bearing gap, a dynamic slide bearing having helical grooves and formed between the rotor and the stationary shaft, and a metal lubricant supplied to the grooves and to the gap. An axial bore is formed in the shaft in a manner to extend in the longitudinal direction of the shaft, and an insertion rod is inserted into the axial bore such that a space extending in the longitudinal direction of the shaft is formed between the inner circumferential surface of the axial bore and the outer circumferential surface of the insertion rod. The space acts as a lubricant reservoir for storing the metal lubricant.

Abstract: According to this invention, a traveling-wave tube amplifier includes a traveling-wave tube having a multistage depressed collector and a power supply for applying operation voltages to the traveling-wave tube. A body voltage (Vb) for a cathode of the traveling-wave tube is set to be lower than a small-signal synchronous voltage (Vbs) at which a small-signal gain of the traveling-wave tube is maximized. As a result, a tube efficiency (.eta.t) of the traveling-wave tube can be increased and an efficiency of the traveling-wave tube amplifier can be increased as compared with a conventional device.