Abstract: A method of producing a capillary tube from glass includes zonally softening a tubular preform having an outer diameter DOD, an inner diameter DID and a diameter ratio Drel—with Drel=DOD/DID—in a heating zone heated to a draw temperature Tdraw and drawing off continuously from the softened region a capillary strand having an outer diameter dAD, an inner diameter dID and a diameter ratio drel—with drel=dOD/dID—at a draw speed vdraw and cutting the capillary to length therefrom. For cost-effective production of a thick-walled capillary by drawing from a preform without strict requirements for the geometry and dimensional accuracy of the preform, the capillary bore is subjected in the heating zone to a shrinkage process based on the action of draw temperature Tdraw and surface tension, such that the diameter ratio drel of the capillary strand is adjusted to a value greater than the diameter ratio Drel of the preform by at least a factor of 5.

Abstract: Apparatus and method for producing elongated glass components with low bow. The apparatus may include a heating element to heat a bulk glass component where a strand may be drawn from the bulk glass component in a downward direction and a gripper device including a clamping element to support the strand while pulling or drawing it from the bulk glass component in a linear motion, and a low-friction mounting element attached to the clamping element which allows translational movement of the clamping element in an x-y plane. The gripper device may further be used to reduce bow in the strand while it is being drawn by moving the clamping element on the mounting element in a direction opposite the direction of any measured transverse acceleration.

Abstract: One aspect is an apparatus for analyzing particles a capillary as a measuring cell with a hollow channel for receiving or passing through a test sample containing the particles includes a light source for generating a light beam, an optical device for coupling the light beam into the hollow channel at an input point for the purpose of illuminating the test sample, and a detector for detecting scattered light exiting the hollow channel. In one aspects, the hollow channel has an internal diameter DH in the range of 10 ?m to 60 ?m, that the light beam has a radial light intensity distribution with a minimum beam diameter DL, wherein the following applies to the diameter ratio DL/DH: 0.05<DL/DH<2.00, and that the light beam has an angle of incidence of less than 2 degrees in relation to the hollow channel's longitudinal axis on entering the hollow channel.

Abstract: A method and apparatus are provided for producing a tube of glass by zonewise heating and softening of a hollow cylinder by a movable heating zone while rotating about its rotation axis. The glass tube is continuously formed by radial expansion of the softened region under action of centrifugal force and/or internal overpressure applied in the hollow-cylinder bore. The method and apparatus make it possible to deform the hollow cylinder in a single or a small number of forming steps into a glass tube having a larger outer diameter and high dimensional accuracy by determining a circumferential position at which the wall thickness is comparatively small, and during heating and softening of the rotating hollow cylinder a coolant is dispensed from a coolant source onto the deformation zone only when or predominantly when the circumferential position having the comparatively small wall thickness passes the coolant source.

Abstract: A method for producing synthetic fused quartz is provided. The method includes evaporating a feedstock material which contains at least one polymerizable polyalkylsiloxane compound, and supplying the feedstock material vapor to a reaction zone, wherein the feedstock material vapor is converted by oxidation and/or by hydrolysis into SiO2 particles. The feedstock material vapor is passed through a membrane filter as a cleaning device to reduce the formation of gel, which is typically associated with the production of synthetic fused quartz.

Abstract: A method for determining the refractive index profile of a preform is provided.

Abstract: Methods for producing glass components and obtainted glass component, e.g. optical fiber preform. A method includes providing a cladding tube (110) with a longitudinal axis including a first and a second bore separated by a chamfered region (114); inserting a spacer (120) into the first bore; inserting a rod (130) into the first bore (116); moving the spacer (120) into the chamfered section (114), causing the spacer (120) to rotate within the chamfered region (114); and rotating the cladding tube (110) into a vertical orientation, whereby the spacer (120) is prevented from entering the second bore (118) and supports the rod (130). Each portion of the chamfered region has a height perpendicular to the longitudinal axis greater than the height of the second bore.

Abstract: A method for producing carbon particles having a core/shell structure includes infiltrating a pore-containing template material with a first precursor for carbon of a first variety, carbonizing the first precursor to form a deposit of the carbon of the first variety, infiltrating the remaining pore space with a second precursor for carbon of a second variety to form a second deposit of the carbon of the second variety which has a second porosity lower than the first porosity, and removing the template material to form the carbon particles. The template material is provided as template particles and the first precursor is provided as precursor particles of meltable and polymerizable material. The infiltration occurs in the molten phase so that the first precursor is foamed before or during the carbonization to form a pore-containing carbon foam. In an intermediate product, pores of the template material are at least partially filled.

Abstract: A method for producing a pore-containing opaque quartz glass includes: (a) producing porous SiO2 granulate particles from synthetically produced SiO2, (b) thermally densifying the SiO2 granulate particles to form partly densified SiO2 granulate particles, (c) forming a dispersion from the partly densified SiO2 granulate particles, (d) comminuting the partly densified SiO2 granulate particles to form a slip containing comminuted SiO2 granulate particles, (e) shaping the slip into a shaped body and forming a porous SiO2 green body with a green density rG, and (f) sintering the SiO2 green body into opaque quartz glass. To produce opaque quartz glass that is also suited for the use of spray granulate, during step (b), partly densified SiO2 granulate particles are produced with a specific surface BET-(A) between 0.025 and 2.5 m2/g, and during step (d), comminuted SiO2 granulate particles are produced with a specific surface BET-(B) between 4 and 10 m2/g.

Abstract: A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.

Abstract: The invention relates to a composite made of a porous carbon and an active material containing sulphur and to method for producing same. A method for producing a composite made of a porous carbon structure and sulphur is disclosed, said composite being characterized by a high capacitance and a low capacitance loss, when used as an electrode material for a lithium-sulphur secondary battery. According to the invention, a dispersion of carbon powder, an active material containing sulphur and an aqueous medium are treated hydrothermally at a temperature sufficient for melting sulphur. The liquid phase which forms, which contains the melted sulphur and water, infiltrates the pores of the porous carbon.

Abstract: A method for producing substrate tubes of quartz glass includes continuously supplying a hollow cylinder of quartz glass to a heating zone, softening the hollow cylinder zonewise in the heating zone, and drawing off a tubular strand from the softened portion. The hollow cylinder has an outer diameter Ca, an inner diameter Ci and an inner bore. The tubular strand has an outer diameter Ta and an inner diameter Ti. The following parameters are applicable to the hollow cylinder and the tubular strand: Ca>180 mm, Cr>3 with Cr=Ca/Ci, Tr<1.6 with Tr=Ta/Ti and Ci/Ti<2.5. The blow pressure in an inner bore is adjusted to a value in the range of 4 to 10 mbar. Substrate tubes, obtained by cutting the tubular strand to the desired length, serve as semi-finished products for the manufacture of preforms for optical fibers.

Abstract: A method for forming a hollow cylinder, in a single step, into a quartz glass tube with a large outer diameter and high dimensional stability is provided. To produce the tube, the cylinder, while rotating, is softened in portions in a heating zone which is moved at a relative feed rate Va and the softened portion is radially expanded by a centrifugal force and/or internal overpressure applied in the hollow cylinder bore so as to form a deformation zone. The radial expansion of the softened portion is carried out at a location-dependent radial expansion rate Vr, the profile of which along the deformation zone has a maximum value Vr,max which is smaller than 20 cm/min. The temperature in a rear heating portion of the heating zone, assigned to the end of the deformation zone, is lower than in a front heating portion assigned to the beginning of the deformation zone.

Abstract: Measurement methods are known for determining the concentration of an ingredient in a body of ceramic or glassy material, in which the optical path length or the signal propagation time of a measurement wave penetrating the body of ceramic or glassy material in a measurement direction is determined and evaluated. Starting therefrom, in order to indicate a non-destructive method for determining a concentration of an ingredient in a body of ceramic or glassy material, which is also suitable for measurement in the production process of the body concerned, it is suggested according to one embodiment that modulated gigahertz radiation is used as the measurement wave.

Abstract: One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, making a glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The silicon dioxide granulate is obtained by providing and processing a silicon dioxide powder. One aspect also relates to silicon dioxide granulate, which is obtained by providing a silicon dioxide powder and processing it. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Abstract: In a known method for pulling a semiconductor single crystal according to the Czochralski method, a semiconductor melt is produced in a silica glass crucible and the semiconductor single crystal is pulled from said melt. The inner wall of the silica glass crucible and the exposed melt surface are in contact with one another and with a respective melt atmosphere in the region of a contact zone running radially around the crucible inner wall, and primary oscillations of the melt are triggered in said contact zone. On this basis, in order to provide a method characterized by reduced melt vibrations and in particular by a simple, short accretion process, according to the invention primary oscillations are triggered which differ from one another in their frequency.

Abstract: A measuring cell includes a cavity for receiving a test sample to be used in a particle detection apparatus. The measuring cell is configured as an optical waveguide for guiding a light beam. The waveguide has a core which has a refractive index nK, extends along a longitudinal axis of the waveguide, has a cross-sectional area AK of less than 80 ?m2 in a cross section perpendicular to the longitudinal axis, and which is surrounded by a cladding having a smaller refractive index than nK. The cavity forms a channel. The channel extends along the longitudinal axis, is formed inside of or in contact with the core, and has at least one open end with an opening area AH of less than 0.2 ?m2.

Abstract: One aspect is a production process including feeding a feed material composition into a reaction zone at a feeding position, wherein the feed material composition is liquid or gaseous or both; reacting the feed material composition in the reaction zone into a first plurality of particles by a chemical reaction; depositing the first plurality of particles onto a substrate surface of a substrate, thereby obtaining a porous silicon dioxide material, having a pore structure, in the form of up to 20 layers superimposing the substrate surface; at least partially removing the porous silicon dioxide material from the substrate surface; and modifying the pore structure of the porous silicon dioxide material, thereby obtaining the porous silicon dioxide material having a further pore structure.

Abstract: A quartz glass body and a process for the preparation of a quartz glass body is disclosed. In one aspect, the process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. One aspect further relates to a quartz glass body which is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.

Abstract: One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, and making a quartz glass body out of at least part of the glass melt. The size of the quartz glass body is reduced to obtain a quartz glass grain. The quartz glass body is processed to make a preform and an opaque quartz glass body is made from the preform. One aspect further relates to an opaque quartz glass body which is obtainable by this process. One aspect further relates to a reactor and an arrangement, which are each obtainable by further processing of the opaque quartz glass body.