Abstract: It is an object of the present invention to provide a method and apparatus for efficiently remove bubbles present on a surface of molten glass, which can solve a problem that bubbles remaining on a surface of molten glass are get inside at a time of forming the glass to cause inside bubbles, to thereby provide a glass substrate of good quality, and which can improve productivity of glass substrates; and to provide a process for producing glass employing the above method for removing bubbles. The present invention provides a method for removing bubbles from molten glass, which is a method for removing floating bubbles on a surface of molten glass, wherein a floating bubble on the surface of molten glass is irradiated with at least one laser beam.

Abstract: To provide a method for preparing a mayenite-containing oxide containing a mayenite type compound and having a hydride ion density of at least 1×1018/cm3 without need for expensive facilities, control of complicated reaction conditions or a long period of reaction time. A method for preparing a mayenite-containing oxide, which comprises a firing step of heating a starting material having a molar ratio of CaO:Al2O3 being from 9:10 to 14:5 based on the oxides at a temperature of from 900 to 1,300° C. to obtain a fired powder and a hydrogenation step of firing the fired powder at a temperature of at least 1,210° C. and lower than 1,350° C.

Abstract: The present invention relates to a method for producing an oxide containing a conductive mayenite type compound and having an electron concentration of 1×1018/cm3 or more, from a raw material which is a combination of a calcium compound and an aluminum compound or is a compound containing calcium and aluminum, each having a molar ratio of calcium oxide and aluminum oxide ranging from 9:10 to 14:5 in terms of the oxides, the method including the steps of: heating and holding the raw material at 900 to 1,300° C. to produce a calcined powder containing at least one oxide selected from the group consisting of a calcium aluminate, calcium oxide and aluminum oxide; and heating and holding the calcined powder at 1,200° C. to less than 1,415° C. under a reduction atmosphere in an inert gas atmosphere or a vacuum atmosphere each having an oxygen partial pressure of 1,000 Pa or less.

Abstract: The present invention relates to a mayenite-type compound in which a part of Ca of a mayenite-type compound containing Ca, Al and oxygen is substituted by at least one kind of an atom M selected from the group consisting of Be, Mg and Sr, in which the mayenite-type compound has an atom number ratio represented by M/(Ca+M) of from 0.01 to 0.50, and at least a part of free oxygen ions in a mayenite-type crystal structure are substituted by anions of an atom having electron affinity smaller than that of an oxygen atom.

Abstract: The present invention relates to a fluorescent lamp including: a discharge space containing a discharge gas and being surrounded by a glass; a discharge electrode; a phosphor; and a mayenite type compound provided on at least a part of an inner surface contacting the discharge gas. According to the fluorescent lamp of the present invention, a fluorescent lamp that has good luminous efficiency of ultraviolet ray from a discharge gas, has good discharge characteristics such as discharge starting voltage and discharge sustaining voltage in a fluorescent lamp, is chemically stable, has excellent oxidation resistance, has excellent sputtering resistance, and can achieve electric power saving is provided.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost. A production method of an electroconductive mayenite type compound comprising a step of subjecting a precursor to heat treatment, is a method for preparing an electroconductive mayenite type compound, comprising a step of subjecting a precursor to heat treatment; wherein the precursor is a vitreous or crystalline material, which contains Ca and Al, in which a molar ratio of (CaO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, and in which a total amount of CaO and Al2O3 is at least 50 mol %, and wherein the heat treatment is heat treatment comprising holding the precursor at a heat treatment temperature T of from 600 to 1415° C. and in an inert gas or vacuum atmosphere with an oxygen partial pressure PO2 in a range of PO2?105×exp [{?7.9×l04/(T+273)}+14.4] in the unit of Pa.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost without need for expensive facilities, a reaction at high temperature and for a long period of time, or complicated control of reaction. A method for preparing an electroconductive mayenite type compound comprises a step of subjecting a precursor to heat treatment, wherein the precursor contains Ca and/or Sr, and Al, a molar ratio of (a total of CaO and SrO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, a total content of CaO, SrO and Al2O3 in the precursor is at least 50 mol %, and the precursor is a vitreous or crystalline material; and the method comprises a step of mixing the precursor with a reducing agent and performing the heat treatment of holding the mixture at 600-1,415° C. in an inert gas or vacuum atmosphere with an oxygen partial pressure of at most 10 Pa.

Abstract: It is an object of the present invention to provide a method and apparatus for efficiently remove bubbles present on a surface of molten glass, which can solve a problem that bubbles remaining on a surface of molten glass are get inside at a time of forming the glass to cause inside bubbles, to thereby provide a glass substrate of good quality, and which can improve productivity of glass substrates; and to provide a process for producing glass employing the above method for removing bubbles. The present invention provides a method for removing bubbles from molten glass, which is a method for removing floating bubbles on a surface of molten glass, wherein a floating bubble on the surface of molten glass is irradiated with at least one laser beam.

Abstract: To provide a method for preparing a mayenite type compound having electroconductivity imparted. A method for preparing an electroconductive mayenite type compound, which comprises melting a raw material containing Al and at least one element selected from the group consisting of Ca and Sr, holding the melt in a low oxygen partial pressure atmosphere having an oxygen partial pressure of not higher than 10 Pa, followed by cooling or annealing in a low oxygen partial pressure atmosphere or in atmospheric air for solidification, thereby to replace oxygen present in cages by electrons in a high concentration.

Abstract: For a PDP, a panel having favorable discharge properties such a high discharge efficiency and a short discharge delay, being chemically stable and capable of electric power saving, is desired. A plasma display panel comprising a front substrate and a rear substrate facing each other via a discharge space, discharge electrodes formed on at least one of the front substrate and the rear substrate, a dielectric layer covering the discharge electrodes, and a protective layer covering the dielectric layer, wherein the protective layer contains a Mayenite compound, and the secondary emission coefficients when Ne and Xe are used as excited ions at an accelerating voltage of 600 V, are respectively at least 0.05 at a secondary electron collector voltage at which secondary electrons can be sufficiently captured.

Abstract: To provide an electron emitter, a field emission display unit, a cold cathode fluorescent tube and a flat type lighting device, which employ an electron emitting material producible at a low cost and in a large amount. A conductive mayenite type compound powder containing at least 50 mol % of a mayenite type compound represented by a chemical formula of either 12CaO.7Al2O3 or 12SrO.7Al2O3 and having a maximum particle size of at most 100 ?m, is used as an electron emitter, whereby an electron emitter, a field emission display unit, a cold cathode fluorescent tube and a flat type lighting device, are realized that are easy to produce and capable of emitting electrons even at a low applied voltage and whereby a large current can be obtained per the same applied voltage surface.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost without need for expensive facilities, a reaction at high temperature and for a long period of time, or complicated control of reaction. A method for preparing an electroconductive mayenite type compound comprises a step of subjecting a precursor to heat treatment, wherein the precursor contains Ca and/or Sr, and Al, a molar ratio of (a total of CaO and SrO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, a total content of CaO, SrO and Al2O3 in the precursor is at least 50 mol %, and the precursor is a vitreous or crystalline material; and the method comprises a step of mixing the precursor with a reducing agent and performing the heat treatment of holding the mixture at 600-1,415° C. in an inert gas or vacuum atmosphere with an oxygen partial pressure of at most 10 Pa.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost. A production method of an electroconductive mayenite type compound comprising a step of subjecting a precursor to heat treatment, is a method for preparing an electroconductive mayenite type compound, comprising a step of subjecting a precursor to heat treatment; wherein the precursor is a vitreous or crystalline material, which contains Ca and Al, in which a molar ratio of (CaO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, and in which a total amount of CaO and Al2O3 is at least 50 mol %, and wherein the heat treatment is heat treatment comprising holding the precursor at a heat treatment temperature T of from 600 to 1415° C. and in an inert gas or vacuum atmosphere with an oxygen partial pressure PO2 in a range of PO2?105×exp[{?7.9×l04/(T+273)}+14.4] in the unit of Pa.

Abstract: It is an object of the present invention to provide a new method for reducing the diameter of a bubble existing in a glass plate. Specifically, the present invention provides a method for reducing the diameter of a bubble existing in a glass plate, which comprises irradiating the vicinity of the bubble existing in the glass plate with a light beam emitted from a light source, to raise the temperature of the glass in the vicinity of the bubble to at least the melting point of the glass to reduce the maximum diameter of the bubble.

Abstract: To provide a method for preparing a mayenite type compound having electroconductivity imparted. A method for preparing an electroconductive mayenite type compound, which comprises melting a raw material containing Al and at least one element selected from the group consisting of Ca and Sr, holding the melt in a low oxygen partial pressure atmosphere having an oxygen partial pressure of not higher than 10 Pa, followed by cooling or annealing in a low oxygen partial pressure atmosphere or in atmospheric air for solidification, thereby to replace oxygen present in cages by electrons in a high concentration.

Abstract: A glass fiber comprising core glass and clad glass, wherein the core glass consists essentially of from 25 to 70 mol % of Bi2O3, from 5 to 74.89 mol % of B2O3+SiO2, from 0.1 to 30 mol % of Al2O3+Ga2O3, and from 0 to 10 mol % of CeO2.

Abstract: An optical amplifying glass having Er doped in an amount of from 0.01 to 10% as represented by mass percentage to a matrix glass comprising, by mol %, BiO2: 20 to 80, B2O3+SiO2: 5 to 75, Ga2O3+WO3+TeO2: 0.1 to 35, Al2O3≦10, GeO2≦30, TiO2≦30, and SnO2≦30, and containing no CeO2.

Abstract: An optical amplifying glass comprising a matrix glass and, added thereto, from 0.01 to 10 wt % of Er, characterized in that said matrix glass substantially comprises, as represented by mol %, 20 to 80 of Bi2O3, 0 to 74.89 of B2O3, 0 to 79.99 of SiO2, 0.01 to 10 of CeO2, 0 to 50 of Li2O, 0 to 50 of TiO2, 0 to 50 of ZrO2, 0 to 50 of SnO2, 0 to 30 of WO3, 0 to 30 of TeO2, 0 to 30 of Ga2O3 and 0 to 10 of Al2O3, with the proviso that said matrix glass contains at least one of B2O3 and SiO2.

Abstract: An optical amplifier glass comprising a matrix glass containing Bi2O3 and at least one of Al2O3 and Ga2O3, and Er doped to the matrix glass, wherein from 0.01 to 10% by mass percentage of Er is doped to the matrix glass which has a total content of Al2O3 and Ga2O3 of at least 0.1 mol %, a content of Bi2O3 of at least 20 mol %, a refractive index of at least 1.8 at a wavelength of 1.55 &mgr;m, a glass transition temperature of at least 360° C. and an optical basicity of at most 0.49.

Abstract: An optical amplifying glass comprising a matrix glass and from 0.001 to 10% by mass percentage of Tm doped to the matrix glass, wherein the matrix glass contains from 15 to 80 mol % of Bi2O3 and further contains at least one component selected from the group consisting of SiO2, B2O3 and GeO2.