Abstract: A method for manufacturing a crystal plate, comprising the steps of adhering one of an amorphous plate and a crystalline body integrally and merging with the amorphous plate and the crystalline body; and separating the amorphous plate from the crystalline body after the crystal structure of the crystalline body is copied to the amorphous plate so that the crystal structure of the crystalline body can be copied to the amorphous plate without the crystal structure in a short time (short period), and it is easy and cheap to form a crystal plate from the amorphous plate.

Abstract: A main valve body has a first passage, a second passage, and an opening which intersects the first passage and the second passage. A main plug body is rotatably inserted into the opening, and has an upper section into which a handle is inserted, and a lower section having a through-hole. An O-ring is seated on an annular groove which is provided in the vicinity of the through-hole. A seal-retaining member for preventing the O-ring from projecting is fitted to an expanded diameter section of the first passage. One end of the seal-retaining member tightly contacts an end surface of the expanded diameter section. A curved surface corresponding to an inner circumferential surface of the opening is formed at the other end of the seal-retaining member.

Abstract: A main valve body has a first passage, a second passage, and an opening which intersects the first passage and the second passage. A main plug body is rotatably inserted into the opening, and has an upper section into which a handle is inserted, and a lower section having a through-hole. An O-ring is seated on an annular groove which is provided in the vicinity of the through-hole. A seal-retaining member for preventing the O-ring from projecting is fitted to an expanded diameter section of the first passage. One end of the seal-retaining member tightly contacts an end surface of the expanded diameter section. A curved surface corresponding to an inner circumferential surface of the opening is formed at the other end of the seal-retaining member.

Abstract: A process for producing structures from synthetic single-crystal pieces having identical major component and crystal systems by chemically bonding to produce integration and simulation. The process of the present invention makes structures of synthetic single-crystals that are placed together like non-crystals. Therefore, with the process of the present invention, new synthetic single-crystal structures of larger or smaller complicated precise shapes having applications in optical, chemical, and physical fields may be produced. The structures from synthetic single-crystal pieces are comprised of a plurality of colorless synthetic single-crystals or colored synthetic single-crystals having the same prime component and either no color or color impurities contained therein.

Abstract: In a process for producing an integrated structure of synthetic corundum single crystals, which is disclosed herein, a synthetic corundum single-crystal ingot is cut to form a first rectangular prism, and one face of the first rectangular prism is optically polished to form a second rectangular prism. Then, the second rectangular prism is cut, along a plane perpendicular to the optically polished face, into a first plate piece which is then surrounded with a jig, and upper and lower surfaces thereof are optically polished to form a second plate piece. The second plate pieces are put one on another with their plane, edges, axes and axial angles of the upper and lower optically-polished faces being aligned with one another, respectively by use of an incorporating jig. The superposed plate pieces are brought into chemical contact with one another and heated at a temperature lower than a melting point of the synthetic corundum, whereby they are closely joined or bonded.