Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO2) and lithium disilicate (Li2O·2SiO2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.20 to less than 0.25, a grain diameter of crystal grains is within a range from 0.1 &mgr;m to 1.0 &mgr;m, surface roughness (Ra) of the substrate after polishing is within a range from 2 Å to 9 Å.

Abstract: Ophthalmic and optical glasses have a composition in weight percent of 4.5-9.5% SiO2, 10-19.5% B2O3, 0-3% Al2O3, 0-5% GeO2, 18—less than 23% La2O3, 0.3—less than 2% Gd2O3, 5.5-13.5% TiO2, 0-7.5% ZrO2, 15-21% Nb2O5, 0-1.5% Ta2O5, 0.3-5% WO3, with the proviso that (Ta2O5+WO3)/B2O3 is 0.5 or below in the ration terms of weight, 2.1-10% ZnO, 0-5% MgO, 7-12.5% CaO, 0-5% SrO, 0-4% BaO, ≧0.1% Li2O+Na2O+K2O in which 0-1% Li2O, 0-1% Na2O and 0-1% K2O, 0-0.5% As2O3 and 0-0.5% Sb2O3 and have a specific gravity of 4.1 or below, and optical constants of a refractive index (nd) exceeding 1.88 and up to 1.93 and an Abbe number j(&ngr; d) within a range from 28 to 31. A preferable range of Nb2O5 is 15.5—less than 20.5% and a more preferable range of Nb2O5 is less 15.5-20%.

Abstract: A glass-ceramic substrate for an information storage medium includes, as a predominant crystal phase, lithium disilicate (Li2O·2SiO2) or a combination of lithium disilicate and at least one crystal phase selected from the group consisting of &agr;-quartz (&agr;-SiO2), &agr;-quartz solid solution (&agr;-SiO2 solid solution), &agr;-cristobalite (&agr;-SiO2) and &agr;-cristobalite solid solution (&agr;-SiO2 solid solution). This substrate has Young's modulus (GPa)/specific gravity of 37 or over, surface roughness Ra (arithmetic mean roughness) of 5.0 Å or below, a coefficient of thermal expansion within a temperature range from −50° C. to +70° C. which ranges from +65×10−7/° C. to +130×10−7/° C. and bending strength of 400 MPa or over.

Abstract: A glass-ceramic substrate for a magnetic head has as its predominant crystal phase a mixed crystal of lithium disilicate (Li.sub.2 O.2SiO.sub.2) and either or both of .alpha.-quartz (.alpha.-SiO.sub.2) and .alpha.-cristobalite (.alpha.-SiO.sub.2), the .alpha.-quartz has a globular grain structure each globular crystral grain being made of aggregated particles and having a grain diameter within a range from 0.1 .mu.m to 3.0 .mu.m, the .alpha.-cristobalite has a globular grain structure each globular grain having a grain diamter within a range from 0.1 .mu.m to 1.0 .mu.m, and surface roughness (Ra) of the glass-ceramic substrate after polishing is within a range from 5 .ANG. to 50 .ANG..

Abstract: There are provided glass-ceramics having a high lithium ion conductivity which include in mol %:______________________________________ P.sub.2 O.sub.5 35-40% SiO.sub.2 0-15% GeO.sub.2 + TiO.sub.2 25-50% in which GeO.sub.2 0 <-50% and TiO.sub.2 0-<50% ZrO.sub.2 0-10% M.sub.2 O.sub.3 (where M is one or 0.5-15% two selected from the group consisting of Al and Ga) Li.sub.2 O 10-25% ______________________________________and containing Li.sub.1+X M.sub.X (Ge.sub.1-Y Ti.sub.Y).sub.2-X (PO.sub.4).sub.3 (where 0<X<0.8 and 0<Y<1.0) as a main crystal phase. There are also provided glass-ceramics having a high lithium ion conductivity which include in mol % ______________________________________ P.sub.2 O.sub.5 32-40% SiO.sub.2 7-14% TiO.sub.2 38-45% Li.sub.2 O 10-18% ______________________________________and containing Li.sub.1+X Ti.sub.2 Si.sub.X P.sub.3-X O .sub.12 (where X>0) as a main crystal phase.

Abstract: There is provided a long-lasting phosphor activated by divalent europium and having a chemical composition RO.multidot.a(Al.sub.1-x Ga.sub.x).sub.2 O.sub.3 .multidot.b(Y.sub.1-y Sc.sub.y).sub.2 O.sub.3 .multidot.cB.sub.2 O.sub.3 .multidot.dEu.sup.2+ .multidot.eM.sup.n+ (where R is at least one selected from the group consisting of alkaline-earth metals including Ba, Sr, Ca and Mg and Zn, and M is at least one auxiliary activator selected from the group consisting of Nb, Zr, Bi, Mn, Sn, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) wherein a, b, c, d, e, x and y are within ranges of:0.3.ltoreq.a.ltoreq.8,0<b.ltoreq.0.2,0.001.ltoreq.c.ltoreq.0.2,0.001.ltoreq.d.ltoreq.0.3,0.001.ltoreq.e.ltoreq.0.3,0.ltoreq.x.ltoreq.1.0, and0.ltoreq.y.ltoreq.1.0.There is also provided a long-lasting phosphor activated by divalent europium and having a chemical composition RO.multidot.a(Al.sub.1-x Ga.sub.x).sub.2 O.sub.3 .multidot.b(Si.sub.1-y Ge.sub.y)O.sub.2 .multidot.cEu.sup.2+ .multidot.dM.sup.

Abstract: A transparent simulation disk for measuring flying height of a magnetic head (i.e., distance between a magnetic head and a magnetic disk such as a hard disk of a computer) in place of a magnetic disk is made of a SiO.sub.2 --R.sub.2 O (where R is Li, Na or K) glass or glass-ceramic having electric resistivity of 10.sup.8 -10.sup.14 .OMEGA.cm and abrasion of 90 or below.

Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2.SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.

Abstract: A glass-ceramic substrate for a magnetic information storage medium such as a magnetic disk having a super flatness suited for a contact recording system includes a SiO.sub.2 --Al.sub.2 O.sub.3 --Li.sub.2 O system glass-ceramic and has either .beta.-quartz solid solution (.beta.-SiO.sub.2 solid solution) or a mixture of .beta.-quartz solid solution (.beta.-SiO.sub.2 solid solution) and .beta.-spodumene solid solution (.beta.-Li.sub.2 O.Al.sub.2 O.sub.3.4SiO.sub.2 solid solution) as its main crystal phase. The surface roughness (Ra) of the glass-ceramic substrate after polishing is within a range from 1 .ANG. to 5 .ANG..

Abstract: An optical glass has a large negative anomalous dispersion value and optical constants of refractive index (nd) within a range of 1.65-1.80 and Abbe number (.nu.d) within a range of 28-42. The optical glass includes, as its essential ingredients, in weight percent, 20-50% SiO.sub.2, 6-20% B.sub.2 O.sub.3 where SiO.sub.2 /B.sub.2 O.sub.3 .ltoreq.6, 0.5-15% ZrO.sub.2 and 31-50% Nb.sub.2 O.sub.5.

Abstract: A crystallized glass and a manufacturing method therefor are disclosed. The crystallized glass comprises .beta.-spodumene solid solution as the predominant crystal phase, and is produced by forming a melted raw glass, cooling and thereafter heat-treating it. The raw glass has a composition comprising, expressed in terms of weight percent: 52-65% SiO.sub.2 ; 8-15% Al.sub.2 O.sub.3 ; 0-4% P.sub.2 O.sub.5, 3-8% TiO.sub.2, and 0-4% ZrO.sub.2, wherein the following inequality is satisfied,0.1<(% of P.sub.2 O.sub.5 +% of ZrO.sub.2)/(% of TiO.sub.2)<0.8; 0-10% ZnO, 0-10% MgO, and 0-5% BaO, wherein the following inequality is satisfied,<(% of ZnO+% of MgO+% of BaO)<15; 3-12% Li.sub.2 O; 0-4% K.sub.2 O; and As.sub.2 O.sub.3 and Sb.sub.2 O.sub.3, wherein the following inequality is satisfied,0<% of As.sub.2 O.sub.3 +% of Sb.sub.2 O.sub.3 <2.

Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2 O . 2SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.

Abstract: An optical glass having optical constants of refractive index within the range of 1.55-1.75 and Abbe number (.nu. d) within the range of 25-51 and having large negative anomalous dispersion which is substantially free of lead and arsenic compounds includes as its essential ingredients in weigth percent 10->40% SiO.sub.2, 12.5-35% B.sub.2 O.sub.3, 3-20% ZrO.sub.2 and 6-30% Nb.sub.2 O.sub.5.

Abstract: A thermoelectric semiconductor material is used for thermoelectric conversion in a thermoelectric conversion device. The material comprises a double oxide having one of a normal spinel crystal structure and an inverse spinel crystal structure, the double oxide comprising a composition that is represented by MIn.sub.2 O.sub.4, wherein M represents a metal element that can be changed into a divalent ion.

Abstract: There are provided glass-ceramics having a high lithium ion conductivity which include in mol %______________________________________ P.sub.2 O.sub.5 38-40% TiO.sub.2 25-45% M.sub.2 O.sub.3 (where M is Al or Ga) 5-15% Li.sub.2 O 10-20% ______________________________________and contain Li.sub.1+X (Al, Ga).sub.X Ti.sub.2-X (PO.sub.4).sub.3 (where X is 0 to 0.8) as a main crystal phases. There are also provided glass-ceramics having a high lithium ion conductivity which include in mol % ______________________________________ P.sub.2 O.sub.5 26-40% SiO.sub.2 0.5-12% TiO.sub.2 30-45% M.sub.2 O.sub.3 (where M is Al or Ga) 5-10% Li.sub.2 O 10-18% ______________________________________and contain Li.sub.1+X+Y M.sub.X Ti.sub.2-X Si.sub.Y P.sub.3-Y O.sub.12 (where 0<X.ltoreq.0.4 and 0<Y.ltoreq.0.6) as a main crystal phase.

Abstract: A thermoelectric semiconductor material is disclosed. The material comprises a double oxide which contains antimony and has a trirutile crystal structure.

Abstract: An optical glass including as its main ingredients in weight percent 25-50% SiO.sub.2, 16-40% B.sub.2 O.sub.3, 5-25% SrO and 1-10% Li.sub.2 O has optical constants of refractive index (Nd) of 1.55-1.65 and Abbe number (.nu.d) of 55-63 and a yield point (At) below 600.degree. C. which is suited for mold pressing.

Abstract: A low expansion crystallized glass-ceramic which has a coefficient of thermal expansion (.alpha..times.10.sup.-7 /.degree. C.) within the range of from -10 to +10, has a remarkably reduced variation in the coefficient of thermal expansion accompanied by variation in heat treatment conditions, has an excellent optical homogeniety owing to reduced melting temperature in the base glass and has an improved transparency is obtained by restricting the ratio in weight of Al.sub.2 O.sub.3 to (SiO.sub.2 +P.sub.2 O.sub.5) within the range of 0.38 and 0.50 and adding MgO, BaO and ZnO of specific content ranges as essential ingredients in a base glass of a SiO.sub.2 -Al.sub.2 O.sub.3 -Li.sub.2 O system containing P.sub.2 O.sub.5 as an optional ingredient and TiO.sub.2 and ZrO.sub.2 as nucleating agents.

Abstract: An optical glass which is a SiO.sub.2 -Nb.sub.2 O.sub.5 -R'.sub.2 O (where R' is an alkali metal element)-F system of a specific composition range exhibits optical constants of a refractive index (Nd) of about 1.52-1.67 and an Abbe number (.upsilon. d) of about 32-50, is free of PbO and has an improved light transmissivity.

Abstract: An optical glass which is a SiO.sub.2 --TiO.sub.2 --K.sub.2 O--RO (where R represents Mg, Ca, Sr, Ba and Zn metal elements) system glass of a specific content range exhibits optical constants of a refractive index (Nd) of about 1.58-1.78 and Abbe number (.nu.d) of about 28-45, is free of PbO and has an improved property against devitrification.