Abstract: A method for producing a liquid composition containing a fluoropolymer having sulfonic acid groups, trivalent cerium ions and water, by (1) irradiating a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water, with light at least partially in a wavelength region from 300 to 400 nm so that the ultraviolet irradiance on the surface of the solution is at least 0.1 mW/cm2 or (2) adding a reducing agent to a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water.

Abstract: The present invention relates to a glass substrate including a pair of main surfaces and an end surface, and having a surface layer diffusion Sn atom concentration of 2.0×1018 atomic/cm3 or more and 1.4×1019 atomic/cm3 or less in at least one of the main surfaces, the surface layer diffusion Sn atom concentration being obtained by subtracting an Sn atom concentration of an inside of the glass substrate from an Sn atom concentration of a surface layer of the glass substrate, in which the Sn atom concentration of a surface layer of the glass substrate is defined as an Sn atom concentration at a depth of 0.1 to 0.3 ?m from the main surface and the Sn atom concentration of an inside of the glass substrate is defined as an Sn atom concentration at a depth of 9.0 to 9.2 ?m from the main surface.

Abstract: Provided are a method for producing a liquid composition which is capable of eliminating clouding of a liquid with cerium (IV) hydroxide particles in a relatively short time, and methods for producing a polymer electrolyte membrane, a catalyst layer and a membrane/electrode assembly, each having excellent durability, in a relatively short time. A method for producing a liquid composition containing a fluoropolymer having sulfonic acid groups, trivalent cerium ions and water, which comprises (1) irradiating a solution containing at least one cerium compound selected from the group consisting of cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water, with light at least partially in a wavelength region from 300 to 400 nm so that the ultraviolet irradiance on the surface of the solution is at least 0.

Abstract: To provide glass to be used for a substrate which is, as a substrate, less susceptible to surface roughening even if subjected to cleaning by means of a strongly acidic solution. Glass for a substrate, which comprises, as represented by mol % based on the following oxides, from 62.5 to 69% of SiO2, from 9 to 15.5% of Al2O3, from 8 to 16 of Li2O, from 0 to 8% of Na2O, from 0 to 7% of K2O and from 0 to 3.5% of ZrO2, provided that SiO2—Al2O3 is at least 53.3%, Li2O+Na2O+K2O is from 17 to 24%, and the total of contents of the above six components is at least 97%.

Abstract: The invention provides a method for etching which is intended for reducing the thickness of a glass substrate, and which attains a high etching rate and is capable of inhibiting haze generation on the glass substrate surface. The invention relates to a method for etching a glass substrate surface, comprising etching the glass substrate surface in an amount of 1-690 ?m in terms of etching amount, in which the etching is conducted with an etchant having an HF concentration of 1-5 wt % and an HCl concentration of 1 wt % or higher.

Abstract: To provide glass to be used for a substrate which is, as a substrate, less susceptible to surface roughening even if subjected to cleaning by means of a strongly acidic solution. Glass for a substrate, which comprises, as represented by mol % based on the following oxides, from 62.5 to 69% of SiO2, from 9 to 15.5% of Al2O3, from 8 to 16 of Li2O, from 0 to 8% of Na2O, from 0 to 7% of K2O and from 0 to 3.5% of ZrO2, provided that SiO2—Al2O3 is at least 53.3%, Li2O+Na2O+K2O is from 17 to 24%, and the total of contents of the above six components is at least 97%.

Abstract: To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO2, from 11.5 to 17% of Al2O3, from 8 to 16% of Li2O, from 2 to 8% of Na2O, from 2.5 to 8% of K2O, from 0 to 6% of MgO, from 0 to 4% of TiO2 and from 0 to 3% of ZrO2, provided that Al2O3+MgO+TiO2 is at least 12%, and Li2O+Na2O+K2O is from 16 to 23%, wherein in a case of where B2O3 is contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120° C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as CLi, CNa and CK respectively, CNa is at most 0.7 nmol/cm2, and CLi+CNa+CK is at most 3.5 nmol/cm2.

Abstract: To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO2, from 11.5 to 17% of Al2O3, from 8 to 16% of Li2O, from 2 to 8% of Na2O, from 2.5 to 8% of K2O, from 0 to 6% of MgO, from 0 to 4% of TiO2 and from 0 to 3% of ZrO2, provided that Al2O3+MgO+TiO2 is at least 12%, and Li2O+Na2O+K2O is from 16 to 23%, wherein in a case of where B2O3 is contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120° C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as CLi, CNa and CK respectively, CNa is at most 0.7 nmol/cm2, and CLi+CNa+CK is at most 3.5 nmol/cm2.

Abstract: To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO2, from 11.5 to 17% of Al2O3, from 8 to 16% of Li2O, from 2 to 8% of Na2O, from 2.5 to 8% of K2O, from 0 to 6% of MgO, from 0 to 4% of TiO2 and from 0 to 3% of ZrO2, provided that Al2O3+MgO+TiO2 is at least 12%, and Li2O+Na2O+K2O is from 16 to 23%, wherein in a case of where B2O3 is contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120° C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as CLi, CNa and CK respectively, CNa is at most 0.7 nmol/cm2, and CLi+CNa+CK is at most 3.5 nmol/cm2.

Abstract: The invention provides a method for etching which is intended for reducing the thickness of a glass substrate, and which attains a high etching rate and is capable of inhibiting haze generation on the glass substrate surface. The invention relates to a method for etching a glass substrate surface, comprising etching the glass substrate surface in an amount of 1-690 ?m in terms of etching amount, in which the etching is conducted with an etchant having an HF concentration of 1-5 wt % and an HCl concentration of 1 wt % or higher.

Abstract: To provide a glass for an information recording media substrate, which is excellent in weather resistance. A glass for an information recording media substrate, which comprises, as represented by mol % based on oxide, from 61 to 66% of SiO2, from 11.5 to 17% of Al2O3, from 8 to 16% of Li2O, from 2 to 8% of Na2O, from 2.5 to 8% of K2O, from 0 to 6% of MgO, from 0 to 4% of TiO2 and from 0 to 3% of ZrO2, provided that Al2O3+MgO+TiO2 is at least 12%, and Li2O+Na2O+K2O is from 16 to 23%, wherein in a case of where B2O3 is contained, its content is less than 1%. The above glass for an information recording media substrate, wherein when the glass is left under steam atmosphere at 120° C. at 0.2 MPa for 20 hours, and the amount of Li, the amount of Na and the amount of K, which precipitate on a surface of the glass are represented as CLi, CNa and CK respectively, CNa is at most 0.7 nmol/cm2, and CLi+CNa+CK is at most 3.5 nmol/cm2.

Abstract: A method for evaluating the quality of abrasive grains for polishing glass, which comprises adding abrasive grains to be measured, to an aqueous medium having silica dissolved therein, to have the silica adsorbed on the abrasive grains under such a condition that the silica undergoes substantially no polymerization in the aqueous medium, followed by solid-liquid separation to separate the abrasive grains from the mother liquor, and measuring the concentration of silica remaining in the mother liquor to measure the adsorption rate (?) of silica on the abrasive grains.

Abstract: A glass forming mold comprising a mold having a molding surface, a chromium coating film formed on the molding surface and a silicon oxide film formed on the surface of the chromium coating film.

Abstract: A method for evaluating the quality of abrasive grains for polishing glass, which comprises adding abrasive grains to be measured, to an aqueous medium having silica dissolved therein, to have the silica adsorbed on the abrasive grains under such a condition that the silica undergoes substantially no polymerization in the aqueous medium, followed by solid-liquid separation to separate the abrasive grains from the mother liquor, and measuring the concentration of silica remaining in the mother liquor to measure the adsorption rate (&eegr;) of silica on the abrasive grains.

Abstract: A glass forming mold comprising a mold having a molding surface, a chromium coating film formed on the molding surface and a silicon oxide film formed on the surface of the chromium coating film.

Abstract: A highly corrosion-resistant silicon carbide product consisting of a sintered body having a content of .alpha.-form silicon carbide of at least 90 wt %, wherein the content of iron is at most 1 ppm, the content of aluminum is at most 5 ppm, and the content of calcium is at most 3 ppm.

Abstract: A glass forming mold which comprises a substrate made of stainless steel and a coating comprising the following components formed as the outermost surface coating on the substrate: (1) from 40 to 94 wt % of nickel and/or cobalt as component A; (2) from 5 to 59 wt % of tungsten as component B; and (3) from 0.5 to 40 wt % of at least one transition element having a melting point of at least 2,200.degree. C. as component C.