Abstract:
A preform for a low loss fiber optic cable and method and apparatus for fabricating such a preform is provided. The method includes providing AlCl3 and CVD precursors and locally doping CaCl3. Alkali and/or alkaline earth fluxing agents can be introduced. The alkali and/or alkaline earths are doped along with the aluminum into the silica glass core.
Abstract:
This ultralow-loss glass is characterized in that high purity silica glass contains 1 to 500 wt.ppm of at least one network modifying oxide. It is assumed that the network modifying oxide appropriately loosens the tetrahedral network structure of silica and hence Rayleigh scattering is decreased. Examples of the network modifying oxide include Na.sub.2 O, K.sub.2 O, Li.sub.2 O, MgO, CaO, and PbO. Since Rayleigh scattering losses are minimal in comparison with those of high purity silica glass, this impurity-added silica glass is excellent as a base material of a glass fiber for a long-distance transmission.
Abstract:
Soft quartz glass having low viscosity and a low thermal coefficient of expansion, high electrical insulation capability and free from release of contaminants, when used as a bulb of an incandescent lamp or as an envelope in an arc vessel of a discharge lamp, is a quartz glass made of ultra-pure quartz (SiO.sub.2), for example having a purity of 99.99 mol-%, doped with stoichiometric compounds of alkaline earth oxides with boron oxide, optionally also with a small quantity of Al.sub.2 O.sub.3 in an overall quantity of the doping substance of between about 0.05% to 0.8%, by weight.
Abstract:
This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, e.g., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal. Thereafter, the resulting glass now characterized by a distribution of internally bonded or immobilized, toxic, radioactive anions can be packaged in suitable containers, and disposed of as by burial, and/or they can be sintered to collapse the pores thereof to disposal or for producing useful radiation sources. The porous glass or a porous silica gel having said silicon-bonded organofunctionalsiloxy groups and/or said hydrous polyvalent metal oxy groups, the pores of said glass or silica gel remaining open and uncollapsed, can be used advantageously as a backfill for an underground radioactive waste burial site and as overpack in the waste disposal container. Also included is a novel method for bonding the polyvalent metal to the porous silica glass or gel by substituting the protons of the silicon-bonded hydroxyl groups thereof with an alkali metal or ammonium cation followed by displacement of said cation with the non-radioactive polyvalent metal cation.
Abstract:
This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, e.g., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal. Thereafter, the resulting glass now characterized by a distribution of internally bonded or immobilized, toxic, radioactive anions can be packaged in suitable containers, and disposed of as by burial, and/or they can be sintered to collapse the pores thereof prior to disposal or for producing useful radiation sources. The porous glass or a porous silica gel having said silicon-bonded organofunctionalsiloxy groups and/or said hydrous polyvalent metal oxy groups, the pores of said glass or silica gel remaining open and uncollapsed, can be used advantageously as a backfill for an underground radioactive waste burial site and as overpack in the waste disposal container. Also included is a novel method for bonding the polyvalent metal to the porous silica glass or gel by substituting the protons of the silicon-bonded hydroxyl groups thereof with an alkali metal or ammonium cation followed by displacement of said cation with the non-radioactive polyvalent metal cation.
Abstract:
본 발명은, Li, Na, K의 합계 농도가 50wt ppm 이하인 기체형성용 원료분말과, Ca, Sr, Ba를 합계 50~2000wt ppm으로 함유하는 내부층형성용 원료분말을 제작하고, 형틀 내에서 기체의 가성형체를 형성하고, 그 내부표면 상에 내부층의 가성형체를 형성하고, 수소 혹은 헬륨 또는 이들 혼합 가스를 10vol.%를 초과하는 비율로 함유하는 가스 분위기에서, 방전 가열 용융법에 의해 기체와 내부층의 가성형체의 내측으로부터 가열시킴으로써, 기체의 가성형체의 외주부분을 소결체로 함과 동시에, 기체의 가성형체의 내주부분 및 내부층의 가성형체를 용융 유리체로 함으로써, 외주부분에 기포를 함유하는 기체와, 이 기체의 내부표면 상에 형성된, 투명 실리카 유리로 이루어진 내부층을 갖는 실리카 용기를 제조하는 방법이다. 이에 따라, 고 치수정밀도, 고 내열성을 갖는 실리카 용기를 저비용으로 제조 가능한 실리카 용기의 제조 방법 및 이러한 실리카 용기가 제공된다.
Abstract:
PURPOSE: An ultra-low loss glass having low Rayleigh scattering loss is provided which is excellent as the mother material of a glass fiber for long distance forwarding by doping impurities to a high purity glass. CONSTITUTION: An ultra low loss glass is obtained by doping at least one metallic oxide selected from Na2O, K2O, Li2O, MgO, CaO, PbO of 1- 500 wt, ppm to a high purity glass which loosen the tetrahedron network structure of silica. The resultant glass is used for the optical fiber due to low Rayleigh scattering compared with a pure silica glass.
Abstract:
A tube glass of the present invention includes an alkali silicate glass, in which a glass composition is substantially free of B2O3 and Al2O3, and a loss in mass ρ (mg/dm2) in an alkali resistance test in accordance with ISO 695 (199105-15) is classified as Class A1.
Abstract:
An optical fiber preform includes a silica-glass core portion, and a cladding portion surrounding the core portion, the cladding portion being composed of a fluorine-containing silica glass having a lower refractive index than the core portion, the core portion including a first region that does not include the central axis thereof, the first region containing a first dopant selected from sodium, potassium, and compounds thereof, and a second region that includes the central axis, the second region containing a second dopant that reduces the viscosity of the silica glass, the second dopant having a diffusion coefficient of 1×10−12 cm2/s or more and less than the first dopant at 2,000° C. to 2,300° C., in which the entire core portion has an average first dopant concentration of 10 atomic ppm or more and 2,000 atomic ppm or less and an average second dopant concentration of 10 atomic ppm or more.
Abstract:
A doped silica-titania glass article is provided that includes a glass article having a glass composition comprising (i) a silica-titania base glass, (ii) a fluorine dopant, and (iii) a second dopant. The fluorine dopant has a concentration of fluorine of up to 5 wt. % and the second dopant comprises one or more oxides selected from the group consisting of Al, Nb, Ta, B, Na, K, Mg, Ca and Li oxides at a total oxide concentration from 50 ppm to 6 wt. %. Further, the glass article has an expansivity slope of less than 0.5 ppb/K2 at 20° C. The second dopant can be optional. The composition of the glass article may also contain an OH concentration of less than 100 ppm.