Abstract: A silicon wafer which has DZ layers formed on both sides thereof by heat treatment in an atmosphere of reducing gas (such as hydrogen) or rare gas (such as argon) with a specific temperature profile for heating, holding, and cooling, and which also has a gettering site of BMD in the bulk inside the DZ layer. A silicon wafer which has a silicon epitaxial layer formed on one side thereof. The DZ layer and the silicon epitaxial layer contain dissolved oxygen introduced into their surface parts, with the concentration and distribution of dissolved oxygen properly controlled. Introduction of oxygen into the surface part is accomplished by heat treatment and ensuing rapid cooling in an atmosphere of oxygen-containing gas.

Abstract: A silicon wafer which has DZ layers formed on both sides thereof by heat treatment in an atmosphere of reducing gas (such as hydrogen) or rare gas (such as argon) with a specific temperature profile for heating, holding, and cooling, and which also has a gettering site of BMD in the bulk inside the DZ layer. A silicon wafer which has a silicon epitaxial layer formed on one side thereof. The DZ layer and the silicon epitaxial layer contain dissolved oxygen introduced into their surface parts, with the concentration and distribution of dissolved oxygen properly controlled. Introduction of oxygen into the surface part is accomplished by heat treatment and ensuing rapid cooling in an atmosphere of oxygen-containing gas.

Abstract: One of the problems to be resolved by the present invention is to stably and sustainably produce active ingredients contained in Bignoniaceous plants of which a mass production is difficult in a conventional manner. The present invention relates to a method for efficiently preparing an anticancer active ingredient NQ801 by a cell cultivation of Bignoniaceous plants under specific culture conditions. An ingredient-production system in the present invention has an anticancer activity.

Abstract: A silicon wafer which has DZ layers formed on both sides thereof by heat treatment in an atmosphere of reducing gas (such as hydrogen) or rare gas (such as argon) with a specific temperature profile for heating, holding, and cooling, and which also has a gettering site of BMD in the bulk inside the DZ layer. A silicon wafer which has a silicon epitaxial layer formed on one side thereof. The DZ layer and the silicon epitaxial layer contain dissolved oxygen introduced into their surface parts, with the concentration and distribution of dissolved oxygen properly controlled. Introduction of oxygen into the surface part is accomplished by heat treatment and ensuing rapid cooling in an atmosphere of oxygen-containing gas.

Abstract: A disk drive apparatus for recording (writing) and/or reproducing (reading) information on an optical disk by rotating the optical disk, and adjusting the tilt angle of an optical pickup device with respect to the optical disk. A spindle chassis rotationally supports a turntable on which the optical disk is placed. A pickup chassis, rotationally supported on said spindle chassis, movably supports an optical pickup device that writes and/or reads the information to/from the optical disk and is movable toward and away from the turntable. A tilt mechanism adjusts the tilt angle of the optical pickup device with respect to the optical disk by rotating the pickup chassis with respect to the spindle chassis.

Abstract: The object of the present invention is to propose an optical disk driving apparatus, an optical disk driving method and an optical disk apparatus capable of reducing the occurrence of disturbance to focus servo control and tracking servo control. In the optical disk driving apparatus, a tilt driving section (27) is provided with waveform shaping unit for shaping a driving current waveform driving a tilt motor (28) for changing the angle of an optical pickup (3) with respect to the rotating surface of an optical disk. Thus, it is possible to prevent the vibration of the optical pickup (3), to reduce disturbance derived from the vibration of an objective lens (8) to focus control and tracking control and to suppress mechanical noise while tilt driving is being performed. Besides, since there is no need to provide a tilt sensor, the optical pickup (3) can be made small in size and therefore, the smaller-sized optical disk driving apparatus can be provided.

Abstract: Lubricant retaining slits (5) are formed on a pair of seal members (2) from end surfaces (2b) thereof facing inside in the axial direction of a nut (1) of a ball screw to intermediate portions of the seal members (2), and foreign bodies removing slits (6) are formed on the seal members (2) from end surfaces (2c) thereof facing outside in the axial direction of the nut (1) to intermediate portions thereof The lubricant retaining slits (5) can positively trap the lubricant invading into the gap between the seal member (2) and the screw shaft and returns the lubricant inside the nut (1). The foreign bodies removing slits (6) can remove the foreign bodies stored on the outer peripheral surface of the screw shaft and discharged outside the nut (1).

Abstract: A slide-feed drive part (27) uses a stepping motor as a slide-feed motor for changing the position of a optical pick-up (3) with respect to the rotation surface of an optical disk (1), and has a micro-controller (31) provided therein and a slide-feed motor controller (32) both for correcting drive current waveforms to drive the stepping motor. Therefore, by correcting the motor driving waveforms, the optical pick-up (3) can be linearly moved with respect to the rotation of the slide-feed motor (14). It is thereby possible to do away with a position sensor and make a fine positional control of the optical pick-up (3) with no variation. As a result of this, it is possible to provide an optical disk driving apparatus, an optical disk driving method, and an optical disk apparatus, which enhances the linearity of the rotation of the motor with a simple construction.

Abstract: This invention relates to improvement of a ball screw unit in which a nut member meshes with a screw shaft via a plurality of balls circulating endlessly. The balls are disposed freely rotatably in line at a predetermined interval in a ball arranging member formed in a belt-like shape. If a relative rotation occurs between the nut member and screw shaft, the balls circulate in the infinite circulation path with the ball arranging member. Guide pieces are projected to both sides of the ball arranging member and guide grooves for accommodating each of the guide pieces are formed along the entire circumference of the infinite circulation path. Therefore, the ball arranging member is introduced by the guide grooves and circulates in the infinite circulation path without being fluttered.

Abstract: A ball screw comprises a screw shaft formed on an outer peripheral surface thereof with a spiral ball rolling groove, a nut member having an inner peripheral surface on which a spiral loaded ball rolling groove corresponding to the spiral ball rolling groove of the screw shaft is formed, both the spiral grooves constituting a loaded ball rolling passage in combination thereof when the screw shaft is fitted to the nut member, a number of balls rolling in the loaded ball rolling passage, and a return pipe having one end connected to one end of the loaded ball rolling passage and another end connected to another end of the loaded ball rolling passage so as to scoop the balls rolling in the loaded ball rolling passage at the one end of the return pipe and return the balls to the loaded ball rolling passage at the other one end of the return pipe.

Abstract: A ball screw assembly includes a screw shaft with a spiral groove, balls along the groove, a nut with the screw shaft relatively rotatable with the balls, and a seal device.

Abstract: A ball screw unit comprising a screw having a helical ball rolling groove on the outer peripheral surface thereof, a nut assembly having a load zone formed of a helical load rolling groove opposing to the ball rolling groove of the screw and a no-load zone forming a ball endless track by establishing communication between the starting end and the terminating end of the load zone, a number of balls rolling within the endless track of the nut assembly and a ball coupler comprised of coupling members for retaining the balls to rotate in their aligned state, wherein guide grooves for guiding the coupling members of the ball coupler are formed in the load zone of the ball endless track such that the coupling members of the ball coupler are moved by each of the balls in the no-load zone of the endless track while each of the balls is guided to move by the coupling members of the ball coupler in the no-load zone of the endless track, and guide sections for guiding the ball coupling members of the ball coupler along

Abstract: A method of removing metallic impurities diffused in a semiconductor substrate, comprising, the semiconductor-substrate-heating step of heating a semiconductor substrate to at least 200.degree. C. or higher and promoting the release and rediffusion of metallic impurities diffused in the semiconductor substrate, and the metallic-impurity-removing step of dissolving the metallic impurities arrived at the surface of the semiconductor substrate with a chemical agent and removing them from the substrate.

Abstract: In a heat history initializing step, a heat treatment in performed in an atmosphere including at least one of hydrogen, helium, and argon while the temperature is increased in a range of 700.degree. C. to 1,000.degree. C. at a rate of 15.degree.-1,000.degree. C./min. In a controlled nuclei growing step, a heat treatment is performed in the above atmosphere while the temperature is kept constant in a range of 850.degree. C. to 980.degree. C. for 0.5-60 minutes.