Abstract: An object of the present invention is to provide a quartz glass body, especially a quartz glass jig for plasma reaction in producing semiconductors having excellent resistance against plasma corrosion, particularly, excellent corrosion resistance against F-based gaseous plasma; and a method for producing the same. A body made of quartz glass containing a metallic element and having an improved resistance against plasma corrosion is provided that contains bubbles and crystalline phase at an amount expressed by projected area of less than 100 mm2 per 100 cm3.

Abstract: Provided are a quartz glass crucible for pulling up a silicon single crystal, with which not only a defectless silicon single crystal can be pulled up but a single crystallization ratio can greatly be improved, and a production method therefor.

Abstract: The present invention has as its object to provide text information to a listener with voice when music is reproduced from a medium on which the text information is stored together with music data and to provide easily and smoothly use of the text information. The present invention is a text information read-out device for reading out text information from a medium on which text information is stored together with music data, including a text information extraction unit for extracting text information, a voice synthesizer obtaining voice data from the extracted text information, and a controller for controlling a read-out timing of the voice data in synchronism with reproduction of music data.

Abstract: There is provided a quartz glass crucible for pulling a silicon single crystal and a production process for the crucible, wherein an inner surface of the crucible is crystallized without addition of impurities during pulling a silicon single crystal, thereby impurities serving as causes of crystal defects being not incorporated into the silicon single crystal, so that deterioration of its inner surface is suppressed to improve a crystallization ratio, and accordingly productivity of the quartz glass crucible as well as a quality of the silicon single crystal is improved, and the quartz glass crucible for pulling a silicon single crystal comprises a crucible base body (3) made of a translucent quartz glass layer and a synthetic quartz glass layer (4) formed on an inner wall surface of the crucible base body (3), wherein a portion encircled by a brown ring on an inner surface of the quartz glass crucible is uniformly crystallized during pulling the silicon single crystal.

Abstract: A crucible with 22 inches or more in inner diameter, which has a small deformation of the body under exposure to abundant heat radiation during pulling a single crystal, and which has no practical problem, and a method of producing the same are disclosed.

Abstract: A method for producing an improved quartz glass crucible for pulling up silicon single crystals comprises forming a premolding by feeding powdered silicon dioxide into the mold and by then forming it into a layer along the inner surface of the mold; forming a crucible base body of a translucent quartz layer by heating the premolding from the inner side, thereby partially melting the powdered silicon dioxide, followed by cooling and solidifying the melt; forming a crystallization-promoter containing layer along the internal wall surface of the crucible body by scattering the crystallization promoter on the surface of the internal wall of the crucible body during or after forming the crucible base body; and forming a synthetic quartz glass inner layer by scattering and fusing a powder of silicon dioxide on the crystallization promoter-containing layer that is formed along the internal wall surface of the crucible base body.

Abstract: A large diameter quartz crucible with an inner diameter of 22 inches or more comprises an opaque silica glass outer layer having bubbles of 10 .mu.m to 250 .mu.m in diameter and 5 mm to 20 mm in thickness and a transparent silica glass inner layer having 0.5% or less in a bubble content and 0.3 mm or more in thickness which is molten and integrated with an inner surface of the outer layer. The outer layer has an OH group concentration of 80 ppm or less and the gas pressure in a bubble in the outer layer is lower than atmospheric pressure so that a volume expansion ratio of the bubble is minimized when being heated in condition of pulling a single crystal.

Abstract: Opaque silica glass having a density of 2.0 to 2.18 g/cm.sup.3, sodium and potassium elements concentrations in the silica glass of each 0.5 ppm or less and an OH group concentration of 30 ppm or less, and containing bubbles which are independent bubbles having the following physical values: a bubble diameter of 300 .mu.m or less, and a bubble density of 100,000 to 1,000,000 bubbles/cm.sup.3, and a production process for opaque silica glass, including: filling quartz raw material grain having a particle size of 10 to 350 .mu.m in a heat resistant mold, heating it in a non-oxidizing atmosphere from a room temperature up to a temperature lower by 50 to 150.degree. C. than a temperature at which the above raw material grain is melted at a temperature-raising speed not exceeding 50.degree. C./minute, then, slowly heating it up to a temperature higher by 10 to 80.degree. C. than the temperature at which the quartz raw material grain is melted at the speed of 10.degree. C.

Abstract: Quartz powder is fed into a rotating mold to form a crucible-like quartz powder layer body with the help of centrifugal force in the mold. The layer is melted by heating through the inner surface with an arc discharge to manufacture an outer crucible member. A hollow cylindrical inner crucible member having a beveled lower edge is welded to the outer crucible member while a temperature of the inner surface portion of the outer crucible member remains at 1400.degree. C. or higher by a remaining heat.

Abstract: In order to reduce concentrations of impurities in an inner layer of a quartz crucible for pulling a silicon single crystal which comprises an outer layer made of quartz glass and an inner layer formed on the inner surface of the outer layer, a migration-preventing layer is formed between the outer and inner layers, wherein the migration-preventing layer prevents migration of the impurities such as alkaline metals included in the natural quartz glass in the outer layer to the synthetic quartz glass in the inner layer.

Abstract: A process for producing opaque silica glass in which a quartz raw material grain having a particle size of 10 to 350 .mu.m is filled into a heat resistant mold, the quartz raw material grain is heated in a non-oxidizing atmosphere from a room temperature up to a temperature lower by 50.degree. to 150.degree. C. than a temperature at which the above raw material grain is melted at a temperature-increase speed not exceeding 50.degree. C./minute, then, slowly heated up to a temperature higher by 10.degree. to 80.degree. C. than the temperature at which the quartz raw material grain is melted at the speed of 10.degree. C./minute or less, and the heated quartz raw material grain is further maintained at the temperature higher by 10.degree. to 80.degree. C. than the temperature at which the quartz raw material grain is melted, followed by cooling down to the room temperature.

Abstract: A porous silica body with a density of 0.1 g/cm.sup.3 to 0.5 g/cm.sup.3 and a density variation of less than 30% is subjected to a first heat-treatment in an ammonia-containing atmosphere, a second heat-sintering in non-oxidizing atmosphere, and further heat-treatment at a temperature in the range of 1400.degree. C. to 2000.degree. C. under an increased pressure of 500 kg/cm.sup.2 or more in a non-oxidizing atmosphere.

Abstract: A rotating cylindrical quartz glass tube is partitioned into at least 3 chambers comprising a pre-heating chamber, a reaction chamber, and a gas desorption chamber. The process comprises pre-heating the starting quartz powder by continuously supplying it into the pre-heating chamber, refining the powder by transferring it into the reaction chamber in which the powder is brought into contact with a chlorine-containing gas atmosphere, and transferring the powder into the gas desorption chamber; the chambers may be partitioned using a sectioning plate having an opening. Alkali metal elements such as sodium and potassium, as well as transition metal elements such as iron, copper, chromium, and nickel are removed from a powder of naturally occurring quartz. The process also removes alkaline earth metal elements such as magnesium and calcium. Furthermore, it is of high productivity because it can be operated continuously to yield high purity quartz powder at a low cost.