Abstract: Provided is a fiber structure having a high dust holding capacity. The fiber structure includes a thick fiber group composed of fibers A each having a single fiber diameter larger than 5 ?m and a thin fiber group composed of fibers B each having a single fiber diameter of 5 ?m or smaller, and has an intermingled region in which the thick fiber group and the thin fiber group are intermingled.

Abstract: Polyvinyl alcohol-based fibers contain a polyvinyl alcohol-based polymer and an adsorbent. With respect to 100 parts by mass of the polyvinyl alcohol-based polymer, 30 to 500 parts by mass of the adsorbent is contained. The polyvinyl alcohol-based fibers have a crystallinity of polyvinyl alcohol ranging from 30% to 60%, a diameter ranging from 5 ?m to 1000 ?m, and a specific surface area ranging from 10 m2/g to 2000 m2/g.

Abstract: The invention provides a plant cultivation device with a double pot structure, which adjustably feeds an appropriate amount of cultivation water inherently necessary corresponding to plant types, and which adjustably feeds the cultivation water corresponding to environments or seasons wherein the plant is cultivated. Inner pot are constructed by facing bottom faces of a pair of vessels, wherein a locking projection and a locking groove positioned on the same periphery as the locking projection are formed in a state that they protrude from the outer periphery of a bottom part of a main body of the vessel, and a through hole in which a water absorption body is installed is formed at the bottom part of the main body, and by integrating the vessels by engaging the respective locking projections with the respective locking grooves each other. The inner pot is housed in an outer pot.

Abstract: The disk changer comprises a first rack member supporting on its one end side a latch pawl adapted to latch a pin, and a second rack member supporting on its other end side a latch pawl adapted to latch the pin, the first and second rack members being slidably supported in parallel with each other. After the first rack member transfers a tray by a predetermined distance, latching of the tray thereon is switched over from the first rack member to the second rack member. The tray is then further transferred by the second rack member.

Abstract: Machining of a hard, brittle and difficultly-machinable workpiece by a grinding wheel made of superabrasive grains. The grinding wheel is rotated at a peripheral speed of 1000 to 5500 m/min., and the grinding wheel and the workpiece are moved relative to each other in the machining direction at a feed speed of at least 30 mm/sec.

Abstract: A precision device including a holding mechanism for holding an object and a supporting mechanism for supporting an operating element, one of which is movable in a predetermined direction. The precision device includes a detecting device for detecting the amount of movement of one of the holding holding and supporting mechanisms in the predetermined direction, and the detecting device includes a scale formed of a material having a coefficient of linear expansion, in a temperature range of -20.degree. to 100.degree. C., of not more than 10.times.10.sup.-7 /.degree.C. as an absolute value. The precision device further includes a detecting device for detecting the amount of thermal expansion of at least a part of the supporting mechanism in the predetermined direction.

Abstract: A work head for attracting and fixing an IC silicon wafer is comprised of an attracting disc and a base seat surrounding the periphery of the attracting disk. The attracting disc is of an inorganic substance shaped and sintered so that the upper layer of the attracting disc is composed of a porous body of porous grain and the lower layer the attracting body is formed with a slightly coarse body of porous grain.The base seat is made airtight being formed and sintered with the same substance as the attracting disc. The attracting disc and the base seat are coupled with glass having a low melting point. The attracting disc is connected to a connecting hole drilled through the base seat and further to a water injecting hole and air sucking hole of a lower base. Before the wafer is attracted, water is injected from the injection hole for soaking the attracting surface. The surface tension of water transfers the wafer to the center of the attracting surface.

Abstract: A grinding wheel that can rotate at high speed to grind flat plates is comprised of a thin conical grindstone fastened to the open end of a rotatable inverted cup, with the grinding edge projecting outwardly from and at an inclined angle with respect to the open end. The grindstone includes a cylindrical fitting part which is fastened to the inside of the cup and a conical grinding part formed by electroplating from a nickel plating solution in which super hard abrasive grains are dispersed. The grindstone can also be prepared by electrodepositing abrasive grains directly onto a flange formed at the open end of the cup.

Abstract: Grinding of flat plates is performed by using a very thin, conical grinding wheel which is attached to the open end of a revolving cup and which projects outwardly from and is inclined with respect to the cup. The peripheral cutting edge of the grinding wheel revolving at high speed is brought into contact with the work. As the grinding wheel is fed, the work is cut by the grinding wheel across its thickness and an undercut part of the work disrupts (i.e. breaks off) by itself to a desired thickness. Thick grinding is also possible if a multiplicity of the grinding wheels are placed one over another at proper intervals.

Abstract: For adaptation to grinding or cutting precise or minute parts, a grinding and/or cutting endless belt is made of grindstone comprising electrodeposited abrasive grains.

Abstract: A grinding wheel that can rotate at high speed to grind flat plates comprised of a thin conical grindstone fastened to the open end of a rotatable inverted cup, with the grinding edge projecting outwardly from and at an inclined angle with respect to the open end. The grindstone includes a cylindrical fitting part which is fastened to the inside of the cup and a conical grinding part formed by electroplating from a nickel plating solution in which super hard abrasive grains are dispersed. The grindstone can also be prepared by electrodepositing abrasive grains directly onto a flange formed at the open end of the cup.

Abstract: A work head for attracting and fixing an IC silicon wafer is comprised of an attracting disc and a base seat surrounding the periphery of the attracting disk. The attracting disc is of an inorganic substance shaped and sintered so that the upper layer of the attracting disc is composed of a porous body of porous grain and the lower layer the attracting body is formed with a slightly coarse body of porous grain.The base seat is made airtight, being formed and sintered with the same substance as the attracting disc. The attracting disc and the base seat are coupled with glass having a low melting point. The attracting disc is connected to a connecting hole drilled through the base seat and further to a water injecting hole and air sucking hole of a lower base. Before the wafer is attracted, water is injected from the injection hole for soaking the attracting surface. The surface tension of water transfers the wafer to the center of the attracting surface.

Abstract: Grinding of flat plates is performed by using a very thin, conical grinding wheel which is attached to the open end of a revolving cup and which projects outwardly from and is inclined with respect to the cup. The peripheral cutting edge of the grinding wheel revolving at high speed is brought into contact with the work. As the grinding wheel is fed, the work is cut by the grinding wheel across its thickness and an undercut part of the work disrupts (i.e. breaks off) by itself to a desired thickness. Thick grinding is also possible if a multiplicity of the grinding wheels are placed one over another at proper intervals.

Abstract: A grinding wheel that can rotate at high speed to grind flat plates is comprised of a thin conical grindstone fastened to the open end of a rotatable inverted cup, with the grinding edge projecting outwardly from and at an inclined angle with respect to the open end. The grindstone includes a cylindrical fitting part which is fastened to the inside of the cup and a conical grinding part formed by electroplating from a nickel plating solution in which super hard abrasive grains are dispersed. The grindstone can also be prepared by electrodepositing abrasive grains directly onto a flange formed at the open end of the cup.