Abstract: There is provided a glass substrate which has the properties required in the use as a substrate for an information recording medium of the next generation such as a perpendicular magnetic recording system, and can be applied as a substrate for an information recording medium of the next generation particularly on the premise of using the glass substrate in a dynamic environment. More particularly, there is provided a glass substrate for an information recording medium which has sufficiently high surface hardness, has a good balance between specific gravity and mechanical strength, and has high strength to withstand high speed rotation or drop impact, and which can be produced with a high productivity adequate for a direct press method, without the occurrence of bubbles in the glass blank or reboil upon pressing even if arsenic components or antimony components are not substantially used.

Abstract: Provided are SiO2—Al2O3-based or Li2O—Al2O3—SiO2-based crystallized glass that solves the cause of cracking and fracture in forming it into large-size shaped articles, that has homogeneous inner quality and that may be produced stably at high efficiency; and a method for producing it. The crystallized glass contains components of SiO2 and Al2O3, wherein the crystal precipitation peak temperature width obtained in differential thermal analysis of amorphous glass, a precursor thereof, is at least 22° C. Preferably, the total amount of the TiO2 component and the ZrO2 component in the crystallized glass is within a range of from 3.0 to less than 4.3%. FIG. 1 is referred to.

Abstract: The present invention provides an inorganic composition for use in information recording medium disc substrate and such, having an excellent surface property capable of sufficiently corresponding with a ramp load system for high density recording, a high degree of tolerability to high speed rotation, and high productivity at a low melting point. Specifically, this invention provides an inorganic composition containing one crystalline phase selected from the group consisting of ?-quartz (?-SiO2), lithium disilicate (Li2Si2O5) and lithium monosilicate (Li2SiO3), or that contain at least a crystalline phase of lithium monosilicate (Li2SiO3), in which a mean particle diameter of a particle showing a crystalline phase contained in the inorganic composition is 1 ?m or less, a ring flexural strength is 300 MPa or more, and a surface roughness (an arithmetic mean roughness) thereof after a polishing process is 10 ? or less.

Abstract: There is provided a precure tread and a retreaded tire using same capable of enhancing the stiffness of the land portion and significantly reducing likelihood of peeling off from the base tire during traveling by optimizing the cross-section shape of the rear surface groove of the precure tread, while maintaining the wet performance from the beginning to the end of wear life. A precure tread 1 has a circumferential groove 2 extending in a circumferential direction of a tire on a front surface which is to be a ground contact surface of the tire and a rear surface groove 4 extending in the circumferential direction of the tire on a rear surface which is to be attached to a base tire 3, the rear surface groove appearing from a tread surface as wear of the tread surface is progressed.

Abstract: For providing glass-ceramics having properties suitable for use as a substrate of an information storage medium of next generation such as one for the perpendicular magnetic recording system without employing arsenic and antimony components which adversely affect human beings and the environment, there are provided glass-ceramics comprising SiO2, Li2O and Al2O3 on oxide basis, comprising lithium disilicate as a crystal phase, and comprising one or more elements selected from the group consisting of Sn, Ce, Mn, W, Ta, Bi, Nb, S, Cl and F.

Abstract: An inorganic composition article used in disk substrate for information recording media, with a low melting point and a high productivity, combining superior surface characteristics capable of sufficiently dealing with a ramp load system for high density recording in both an in-plane magnetic recording system and a perpendicular magnetic recording system, having a high mechanical strength capable of enduring high speed rotation and impact, and combining both a heat expansion characteristic and heat resistance corresponding to each drive component. The inorganic composition articles contain a Li2O component and an Al2O3 component, with the percent by mass ratio of Li2O to Al2O3 (Li2O/Al2O3) being at least 0.3, include crystals, and have a compressive stress layer arranged on a surface.

Abstract: It is an object of the present invention to provide a method for producing glass in which the temperature distribution between around a central portion and around a side wall of a shaping mold (temperature distribution between around a central portion and around a side wall of molten glass in the shaping mold) is regulated within a range of ±150° C. to produce large-size glass, and to provide a device for shaping glass used in the method for producing glass. The object may be attained by carrying out a step of flowing the molten glass in a melting furnace, through a pipe to which a heat-insulating member is fixed to prevent the heat dissipation of the molten glass, into the shaping mold covered with a low heat-conductive member, and a step of maintaining the distance between the lower portion of the heat-insulating member and the liquid surface of the molten glass.

Abstract: Provided are SiO2—Al2O3-based or Li2O—Al2O3—SiO2-based crystallized glass which has various properties intrinsic to the crystallized glass of the type and which contains an arsenic component or an antimony component in an amount as small as possible or does not contain an arsenic component and an antimony component; and a method for producing the crystallized glass. The crystallized glass contains components of SiO2 and Al2O3 (as oxides) and contains an SnO2 component (as oxide) and/or a CeO2 component (as oxide). Preferably, the glass contains from 0.01 to 5.0% (as oxide) of an SnO2 component and/or from 0.01 to 5.0% (as oxide) of a CeO2 component.

Abstract: Provided are SiO2—Al2O3-based or Li2O—Al2O3—SiO2-based crystallized glass that solves the cause of cracking and fracture in forming it into large-size shaped articles, that has homogeneous inner quality and that may be produced stably at high efficiency; and a method for producing it. The crystallized glass contains components of SiO2 and Al2O3, wherein the crystal precipitation peak temperature width obtained in differential thermal analysis of amorphous glass, a precursor thereof, is at least 22° C. Preferably, the total amount of the TiO2 component and the ZrO2 component in the crystallized glass is within a range of from 3.0 to less than 4.3%. FIG. 1 is referred to.

Abstract: There are provided glass-ceramics having an ultra low thermal expansion property and super flat surface capable of coping with lithography for the next generation LSI and component parts for semiconductor equipment such as masks, optical reflecting mirrors, wafer stages and reticle stages and various precision parts using such glass-ceramics. Glass-ceramics of the invention have an average linear thermal expansion coefficient within a range of 0.0±0.2×10?7/° C. within a temperature range from 0° C. to 50° C., have difference between the maximum value and the minimum value of ?L/L of 10×10?7 or below, and comprise SiO2, Al2O3 and P2O5 with the total amount thereof in mass % being within a range from 86.0% to 89.0%.

Abstract: The present invention provides an inorganic composition for use in information recording medium disc substrate and such, having an excellent surface property capable of sufficiently corresponding with a ramp load system for high density recording, a high degree of tolerability to high speed rotation, and high productivity at a low melting point. Specifically, this invention provides an inorganic composition containing one crystalline phase selected from the group consisting of ?-quartz (?-SiO2), lithium disilicate (Li2Si2O5) and lithium monosilicate (Li2SiO3), or that contain at least a crystalline phase of lithium monosilicate (Li2SiO3), in which a mean particle diameter of a particle showing a crystalline phase contained in the inorganic composition is 1 ?m or less, a ring flexural strength is 300 MPa or more, and a surface roughness (an arithmetic mean roughness) thereof after a polishing process is 10 ? or less.

Abstract: There are provided low expansion transparent glass-ceramics obtained by heat treating a base glass produced at a relatively low melting temperature of 1530° C. or below. The glass-ceramics have an average linear thermal expansion coefficient within a range from +6×10?7/° C. to +35×10?7/° C., 80% transmittance wavelength (T80) of 700 nm or below, internal transmittance of 75% or over at light wavelength of 1550 nm, heat resisting temperature of 800° C. or over and Young's modulus of 90 GPa or over. The glass-ceramics comprise SiO2, Al2O3, MgO, CaO, BaO, ZnO, Li2O, TiO2 and ZrO2 and contain ?-quartz or ?-quartz solid solution as a predominant crystal phase. There are also provided optical waveguide elements and an arrayed waveguide grating (AWG) type planar lightwave circuit utilizing these glass-ceramics.

Abstract: Glass for a light filter capable of preventing variation of refractive index in a band-pass filter has a coefficient of thermal expansion within a range from 90×10?7/° C. to 120×10?7/° C. within a temperature range from ?20° C. to +70° C. and, preferably, Young's modulus of 75 GPa or over and Vickers hardness of 550 or over, and light transmittance for plate thickness of 10 mm of 90% or over within a wavelength range from 950 nm to 1600 nm.

Abstract: There are provided low expansion transparent glass-ceramics obtained by heat treating a base glass produced at a relatively low melting temperature of 1530° C. or below. The glass-ceramics have an average linear thermal expansion coefficient within a range from +6×10?7/° C. to +35×10?7/° C., 80% transmittance wavelength (T80) of 700 nm or below internal transmittance of 75% or over at light wavelength of 1550 nm, heat resisting temperature of 800° C. or over and Young's modulus of 90 GPa or over. The glass-ceramics comprise SiO2, Al2O3, MgO, CaO, BaO, ZnO, Li2O, TiO2 and ZrO2 and contain ?-quartz or ?-quartz solid solution as a predominant crystal phase.

Abstract: Glass for a light filter capable of preventing variation of refractive index in a band-pass filter has a coefficient of thermal expansion within a range from 90×10?7/° C. within a temperature range from ?20° C. to +70° C. and, preferably, Young's modulus of 75 GPa or over and Vickers hardness of 550 or over, and light transmittance for plate thickness of 10 mm of 90% or over within a wavelength range from 950 nm to 1600 nm.

Abstract: Obtaining previously a relation between a crystallization temperature and a physical property and a relation between a physical property parameter and the physical property of a glass ceramic, measuring the physical property parameter with respect to the glass ceramic sampled from a manufacturing line of the glass ceramic and controlling an actual crystallization temperature based on the relations so that the manufactured glass ceramic has the desired physical property value.

Abstract: There are provided glass-ceramics having an ultra low thermal expansion property and super flat surface capable of coping with lithography for the next generation LSI and component parts for semiconductor equipment such as masks, optical reflecting mirrors, wafer stages and reticle stages and various precision parts using such glass-ceramics. Glass-ceramics of the invention have an average linear thermal expansion coefficient within a range of 0.0±0.2×10?7/° C. within a temperature range from 0° C. to 50° C., have difference between the maximum value and the minimum value of ?L/L of 10×10?7 or below, and comprise SiO2, Al2O3 and P2O5 with the total amount thereof in mass % being within a range from 86.0% to 89.0%.

Abstract: An information storage disk holding member for holding an information storage disk in position in an information storage disk drive device, the holding member being made of glass-ceramics in which a crystal phase is dispersed in a glass matrix. The holding member has specific rigidity (Young's modulus/specific gravity) of not greater than 37 GPa, specific gravity of not greater than 3.0, coefficient of thermal expansion within a range from −50° C. to +70° C. which is within a range from +35×10−7/° C. to +130×10−7/° C., Young's modulus within a range from 95 GPa to 130 GPa, specific gravity within a range from 2.40 to 2.60 and bending strength within a range from 400 MPa to 800 MPa.

Abstract: Glass for a light filter capable of preventing variation of refractive index in a band-pass filter has a coefficient of thermal expansion within a range from 90×10−7/° C. to 120×10−7/° C. within a temperature range from −20° C. to +70° C. and, preferably, Young's modulus of 75 GPa or over and Vickers hardness of 550 or over, and light transmittance for plate thickness of 10 mm of 90% or over within a wavelength range from 950 nm to 1600 nm.

Abstract: A negative thermal expansion glass ceramic having a negative coefficient of thermal expansion, which is a sufficiently large absolute value in a temperature range of ?40° C. to +160° C. and a method for producing the same are provided. The negative thermal expansion glass ceramic has a coefficient of thermal expansion of ?25 to ?100×10?7/° C. in the temperature range of ?40° C. to +160° C., and comprises main crystalline phases which are one or more types selected from a group consisting of ?-eucryptite solid solution (?-Li2O•Al2O3•2SiO2 solid solution), ?-eucryptite (?-Li2O•Al2O3•2SiO2), ?-quartz solid solution (?-SiO2) solid solution), and ?-quartz (?-SiO2), wherein a total amount of crystals of the main crystalline phases can be 70 to 100% in mass percent.