Abstract: A magnetic-disk substrate according to an embodiment includes two main surfaces and an outer circumferential edge surface. In the magnetic-disk substrate, the outer circumferential edge surface includes two chamfered surfaces that are respectively connected to the main surfaces, and a side wall surface that is curved and extends to protrude outward between the two chamfered surfaces. The side wall surface has a radius of curvature of 1100 ?m or more on a cross-section of the magnetic-disk substrate extending along a plate thickness direction of the magnetic-disk substrate.

Abstract: An annular glass plate has an outer circumferential edge surface, an inner circumferential edge surface, and a thickness not larger than 0.6 mm. The outer circumferential edge surface and the inner circumferential edge surface are constituted by molten surfaces. The molten surfaces in the outer circumferential edge surface and the inner circumferential edge surface each have an arithmetic average surface roughness Ra not larger than 0.1 ?m and the surface roughness of the molten surface in the inner circumferential edge surface is larger than the surface roughness of the molten surface in the outer circumferential edge surface. The molten surfaces in the inner circumferential edge surface and the outer circumferential edge surface do not bulge relative to both main surfaces of the annular glass plate.

Abstract: A method for manufacturing a glass plate includes processing for irradiating an inner circumferential edge surface extending along an inner hole in an annular glass plate with a laser beam along the inner circumferential edge surface. When the inner circumferential edge surface is irradiated with the laser beam, the laser beam is concentrated by a condenser lens and formed into diffused light, and the inner circumferential edge surface is irradiated with the diffused light from a direction inclined with respect to a main surface of the glass plate.

Abstract: A method for manufacturing an annular glass plate that has an outer circumferential edge surface, an inner circumferential edge surface, and a thickness not larger than 0.6 mm includes processing for manufacturing an annular glass plate by irradiating each of the outer circumferential edge surface and the inner circumferential edge surface of an annular glass blank with a laser beam to melt the outer circumferential edge surface and the inner circumferential edge surface and form molten surfaces such that the molten surfaces in the outer circumferential edge surface and the inner circumferential edge surface each have an arithmetic average surface roughness Ra not larger than 0.1 ?m, and the surface roughness of the molten surface in the inner circumferential edge surface becomes larger than the surface roughness of the molten surface in the outer circumferential edge surface.

Abstract: In a method for manufacturing a glass plate that includes chamfering processing for chamfering an edge surface of a glass plate, the chamfering processing includes a step of forming a chamfered surface by irradiating the edge surface of the glass plate with a laser beam, and a step of heating the glass plate before the chamfered surface is formed. When a temperature of the glass blank at which the glass blank is heated is Tp [° C.], a glass transition point of the glass blank is Tg [° C.], and an average coefficient of linear thermal expansion of the glass blank is ? [1/° C.], (Tg?Tp)??5.67×107·?+840 is satisfied.

Abstract: A magnetic-disk glass substrate contains an alkaline earth metal component as a glass composition and includes a pair of main surfaces, and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface having a roughness percentage of 40% or more and 68% or less when a bearing ratio of a roughness cross-sectional area is 50% in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained after the outer circumferential side edge surface is etched by 2.5 ?m is measured. A glass transition point of the glass composition that constitutes the magnetic-disk glass substrate is 700° C. or more. The glass composition that constitutes the magnetic-disk glass substrate is alkali-free glass.

Abstract: A method for producing an intermediate glass plate includes a defect formation step, a separation step, and a polishing step. In the defect formation step, a defect is formed on main surfaces of glass blanks by irradiating a laminate of the glass blanks with a laser beam from one side in a lamination direction in which the glass blanks are laminated, along the lamination direction, and moving the laser beam relative to the laminate such that a circle is drawn in a view from the main surfaces of the glass blanks. In the separation step, a cylindrical laminate is formed by separating a removal target portion along the defect while maintaining the laminate. In the polishing step, a side wall surface of the laminate is polished while maintaining the cylindrical laminate so as to obtain a disk-shaped intermediate glass plate that has been subjected to edge surface polishing.

Abstract: Chamfering processing for chamfering an edge face of a disk-shaped glass plate includes a step of disposing the glass plate such that a portion of the glass plate is disposed in a heating space for heating the glass plate and the remaining portion is disposed outside the heating space; and a step of softening a portion of the edge face of the glass plate by irradiating a circumferential portion of the edge face with a laser beam outside the heating space while rotating the glass plate in one direction around the center of the glass plate, and heating the softened portion of the edge face that has reached the heating space through the rotation.

Abstract: A method for manufacturing an annular glass plate that has an outer circumferential edge surface, an inner circumferential edge surface, and a thickness not larger than 0.6 mm includes processing for manufacturing an annular glass plate by irradiating each of the outer circumferential edge surface and the inner circumferential edge surface of an annular glass blank with a laser beam to melt the outer circumferential edge surface and the inner circumferential edge surface and form molten surfaces such that the molten surfaces in the outer circumferential edge surface and the inner circumferential edge surface each have an arithmetic average surface roughness Ra not larger than 0.1 ?m, and the surface roughness of the molten surface in the inner circumferential edge surface becomes larger than the surface roughness of the molten surface in the outer circumferential edge surface.

Abstract: When a laser beam is used to perform shape processing on an edge surface of a disk-shaped glass plate, in order to suppress strain (retardation values) in the main surface of the glass plate, the disk-shaped glass plate is floated above a base, and the edge surface of the glass plate is processed into a target shape by irradiating the edge surface with the laser beam while contactlessly heating the glass plate in a state where the glass plate is floated, and moving the laser beam relative to the edge surface in the circumferential direction of the disk-shaped glass plate.

Abstract: A magnetic-disk glass substrate contains an alkaline earth metal component as a glass composition and includes a pair of main surfaces, and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface having a roughness percentage of 40% or more and 68% or less when a bearing ratio of a roughness cross-sectional area is 50% in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained after the outer circumferential side edge surface is etched by 2.5 ?m is measured. A glass transition point of the glass composition that constitutes the magnetic-disk glass substrate is 700° C. or more. The glass composition that constitutes the magnetic-disk glass substrate is alkali-free glass.

Abstract: A valve removal method of a fluid pipeline structure, which removes an unnecessary portion of a valve device from a connection port portion side of a pipe without flow disruption in the fluid pipeline structure that detachably includes the valve device including a valve body, which is openable and closeable from a direction intersecting a flow path axis of a connection port portion, on the connection port portion side of the pipe connected to a fluid piping system includes a valve body fixing step of fixing the valve body at a closed valve position to the connection port portion side in a sealed manner; and a valve component removing step of removing other unnecessary valve components of the valve device in a state where the valve body which is fixed in a sealed manner is left on the connection port portion side.

Abstract: A method for manufacturing a disk-shaped glass plate in which shape processing is performed on an edge surface of the glass plate includes processing the edge surface into a target shape by irradiating the edge surface with a laser beam while moving the laser beam relative to the edge surface in a circumferential direction of the glass plate. A cross-sectional intensity distribution of the laser beam with which the edge surface is irradiated is a single mode, and W1>Th holds true and Pd×Th is in a range of 0.8 to 3.5 [W/mm] when a width of luminous flux of the laser beam in a thickness direction of the glass plate at an irradiation position of the edge surface is W1 [mm], a thickness of the glass plate is Th [mm], and a power density of the laser beam is Pd.

Abstract: A gate valve includes a valve body for insertion through a through-hole formed in the fluid pipe, and a movement mechanism for moving the valve body along the diameter direction, and the valve body includes a valve main body and a seal member that is capable of undergoing elastic deformation and is provided on a holding portion of the valve main body. A core member formed from a material harder than the seal member is embedded between an outer face of the seal member, which is on the lower side in the movement direction, and a leading end face on the protruding side of the holding portion.

Abstract: A magnetic-disk glass substrate contains an alkaline earth metal component as a glass composition and includes a pair of main surfaces, and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface having a roughness percentage of 40% or more when a bearing ratio of a roughness cross-sectional area is 50% in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained after the outer circumferential side edge surface is etched by 2.5 ?m is measured.

Abstract: The present invention provides a method for controlling a plant disease which comprises applying a compound represented by formula (I) [wherein Z represents a C1-C6 chain hydrocarbon group and the like, R1 and R2 are identical to or different from each other and represent a hydrogen atom or a fluorine atom, and R3, R4, R5, R6 and R7 are identical to or different from each other and represent a C1-C6 chain hydrocarbon group and the like] to a plant or a soil, which has excellent control efficacies against plant diseases.

Abstract: A method for manufacturing a glass substrate including an opening includes forming lines of inner and outer circumferential portions irradiated with a laser beam along substantially concentric circles in a surface of a glass blank, separating a portion on an inner side of the line of the outer circumferential portion of the glass blank and a portion on an outer side of the line of the outer circumferential portion from each other by heating the portion on the outer side of the line of the outer circumferential portion with radiant heat and separating a portion on an inner side of the line of the inner circumferential portion of the glass blank and a portion on an outer side of the line of the inner circumferential portion from each other by heating the portion on the outer side of the line of the inner circumferential portion with radiant heat.

Abstract: A gate valve includes a valve body for insertion through a through-hole formed in the fluid pipe, and a movement mechanism for moving the valve body along the diameter direction, and the valve body includes a valve main body and a seal member that is capable of undergoing elastic deformation and is provided on a holding portion of the valve main body. A core member formed from a material harder than the seal member is embedded between an outer face of the seal member, which is on the lower side in the movement direction, and a leading end face on the protruding side of the holding portion.

Abstract: A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 ?m is measured.

Abstract: A glass blank is cut out from a glass plate by forming a crack starting portion inside the glass plate by moving a first laser beam relative to the glass plate such that a focal position of the laser beam is located in an inner portion of the glass plate in its thickness direction and the focal position forms a circle when viewed from a surface of the glass plate, then causing cracks to develop from the crack starting portion toward main surfaces of the glass plate, and splitting the glass plate to separate, from the glass plate, a glass blank that includes a separation surface having an arithmetic average surface roughness Ra smaller than 0.01 ?m and a roundness not larger than 15 ?m. Thereafter, main surfaces of the glass blank are ground or polished.