Abstract: One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

Abstract: One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

Abstract: The present invention relates to an outer-diameter blade, an inner-diameter blade and cutting machines which respectively use the outer-diameter blade and the inner-diameter blade for cutting hard material, such as metal, ceramics, semiconductor single crystal, glass, quartz crystal, stone, asphalt or concrete, and a core drill and a core-drill processing machine which drives the core drill for forming a hole in the hard material.

Abstract: A core drill having a shank and a cup shaped base metal section constructed of a disk shaped top wall and a cylindrical side wall provided on a fore-end of the shank. A grinding stone portion is mounted on an outer end part of the base metal section, with abrasive grains fixed to the outer end part of the base metal section. Abrasive grain layers are formed in a spiral pattern on inner and outer side surfaces of the cylindrical side wall of the base metal section, with abrasive grains fixed to the inner and outer side surfaces of the cylindrical side wall thereof. When the grinding stone portion is put into rotational contact with a workpiece, the workpiece is ground through to form a circle hole in section leaving a cylindrical core therein.

Abstract: An efficient method is proposed for the utilization of heretofore useless extremely fine fluffy silica particles obtained as a flue dust in the flame-hydrolysis of vaporizable silicon compound in an oxyhydrogen flame in the manufacturing process of fused silica glass. The method comprises the steps of (a) uniformly mixing the silica particles with water, (b) drying the wet mixture under specified conditions to give dried cakes of the silica particles, (c) disintegrating the dried cakes into porous silica beads having an appropriate particle diameter, (d) semi-sintering the porous silica beads at 800 to 1300° C. and (e) vitrifying the semi-sintered silica beads at 1350 to 1550° C. into vitrified poreless silica glass particles which can be used as a base material for the production of fused silica glass articles.

Abstract: A method of preparing a high purity massive synthetic silica glass article. The method includes a homogenizing step, wherein a rod shaped synthetic silica glass material has a greater optical homogeneity in a plane perpendicular to its rotational axis than a plane parallel thereto, a step of forming the homogeneous synthetic silica glass and a step of cutting the formed synthetic silica glass.

Abstract: Provided are an outer-diameter blade, an inner-diameter blade and cutting machines using both blades for cutting hard material, and a core drill and a core-drill processing machine for forming a hole into hard material, whereby the mechanical processing with reduction in the cutting and/or contact resistance to the tools is realized, so that in the case of the outer-diamond blade, it is prevented from occurring that a to-be-cut object is warped and put into contact to the blade to cause chipping; in the case of the inner-diameter blade, it is prevented from occurring that the blade is bowed and/or a cutting surface is curved; and in the case of the core drill, not only are grinding powder of a workpiece and loosed-off abrasive grains effectively removed to prevent those from being loaded between the drill and the workpiece, but neither of cracking and chipping occur when the drill passes through the workpiece.

Abstract: A method of preparing a ball-shaped synthetic silica glass optical article. The method includes a step of providing a rod-shaped synthetic silica glass having end faces at both sides thereof and having fewer cords per unit volume viewed in a direction perpendicular to a line connecting the end faces relative to the number of cords per unit volume viewed in a direction along the line connecting the end faces. The synthetic silica glass being optically homogeneous in the direction perpendicular to the line connecting the end faces. The method includes the further step of establishing support portions at the end faces of the synthetic silica glass. The rod-shaped synthetic silica glass is thereupon heated while being rotated around an axis connecting the support portions wherein a molten zone is formed.

Abstract: A high purity ball-shaped optical article formed of silica glass useful in optical systems employed in photolithography applications. The optical article is characterized by end faces and a side face positioned between the end faces. The side face is externally projected beyond the outline of the end faces and has a spherical configuration. The optical article is uniquely characterized by a smaller number of cords per unit area, viewed in a direction perpendicular to a line connecting the end faces, than the number of cords per unit area viewed in a direction along the line connecting the end faces. The article is also defined by optical homogeneity in a direction perpendicular to the line connecting the end faces.