Abstract: A ferritic steel having tensile properties and fatigue properties capable of withstanding use in a hydrogen environment and a method of manufacture thereof are provided. By adding one or more element selected from among vanadium (V), titanium (Ti) and niobium (Nb) so that the steel includes, together with at least ferrite grains in the structure, a carbide or carbides of one or more element selected from among V, Ti and Nb, the reduction of area and the fatigue crack propagation rate of the ferritic steel in a hydrogen environment are improved. The advantages of the invention were confirmed in cases where the ferrite grains are small grains of 1 ?m or less in size, and in cases where the ferrite grains are coarse grains from several micrometers to 20 ?m in size, and moreover in cases where the ferrite grains are coarse grains from several micrometers to 60 ?m in size.

Abstract: The frequency of replacement of an insulating spacer disposed between grids of an ion beam irradiation apparatus is to be reduced. In addition, the intervals of the multiple grids in the ion beam irradiation apparatus are to be kept constant. To achieve these objects, in a so-called insulating spacer provided for maintaining insulation between the grids, a groove portion having a bottom onto which sputtered materials are hard to adhere is provided on the central portion of the side surface of the insulating spacer all along its circumference.

Abstract: Disclosed is a structure aimed to reduce the frequency of replacement of an insulating spacer arranged between grids of an ion beam irradiation device. More specifically, disclosed is a so-called insulating spacer arranged in order to maintain insulation between the grids, the insulating spacer having an annular groove in a portion composed of an annular, substantially plane portion opposed to a grid and a cylindrical portion being raised from the central portion of the annular, substantially plane portion and abutting the grid, with the annular groove being perpendicular to the plane and separating the peripheral portion of the annular portion from the cylindrical portion.

Abstract: Disclosed is a structure aimed to reduce the frequency of replacement of an insulating spacer arranged between grids of an ion beam irradiation device. More specifically, disclosed is a so-called insulating spacer arranged in order to maintain insulation between the grids, the insulating spacer having an annular groove in a portion composed of an annular, substantially plane portion opposed to a grid and a cylindrical portion being raised from the central portion of the annular, substantially plane portion and abutting the grid, with the annular groove being perpendicular to the plane and separating the peripheral portion of the annular portion from the cylindrical portion.

Abstract: The frequency of replacement of an insulating spacer disposed between grids of an ion beam irradiation apparatus is to be reduced. In addition, the intervals of the multiple grids in the ion beam irradiation apparatus are to be kept constant. To achieve these objects, in a so-called insulating spacer provided for maintaining insulation between the grids, a groove portion having a bottom onto which sputtered materials are hard to adhere is provided on the central portion of the side surface of the insulating spacer all along its circumference.

Abstract: The present invention provides a method of designing a high fatigue strength in high tensile strength steel, comprising: obtaining values of tensile strength &sgr;B (unit thereof is MPa) and Vickers hardness Hv of the steel; measuring a flaw area of an inclusion, when a fracture origin is located only at a surface of the steel; and estimating, in designing the high fatigue strength steel, that a fatigue limit &sgr;w (unit thereof is MPa) of the steel satisfies either &sgr;w≧0.5 &sgr;B or &sgr;w≧1.6 Hv, when a square root of the flaw area, (area)½ (unit thereof is m), contained in the steel is no larger than 45.8/&sgr;B2 or 4.47/Hv2. According to the present invention, a method of evaluating high fatigue strength in high tensile strength steel, in which method a relationship between a flaw dimension (area) of ODA and the fatigue strength is considered, and a high fatigue strength material can be provided.

Abstract: The present invention provides a method of designing a high fatigue strength material in high tensile strength steel, comprising the steps of: obtaining the values of tensile strength &sgr;B (unit thereof is MPa) and Vickers hardness Hv of the steel; measuring the flaw area of inclusion, when the fracture origin is located only at the surface of the steel; and estimating, in designing the high fatigue strength material, that the fatigue limit &sgr;w (unit thereof is MPa) of the steel satisfies either &sgr;w≧0.5&sgr;B or &sgr;w≧1.6 Hv, when a square root of the flaw area, (area)½ (unit thereof is m), contained in the steel is no larger than 45.8/&sgr;B2 or 4.47/Hv2. According to the present invention, a method of evaluating high fatigue strength material in high tensile strength steel, in which method the relationship between the flaw dimension (area) of ODA and the fatigue strength is considered, as well as a high fatigue strength material, can be Provided.