摘要:
A process for producing tubes or rods is provided. The process includes providing a settable liquid and producing a strand by drawing the liquid from a nozzle in a drawing direction. The result of this is that the settable liquid emerges through an annular gap formed by the nozzle with the desired production throughput at the temperature which is above the devitrification temperature. The settable liquid cools as it flows down an outer and/or an inner surface of a displacement body so that, by the end of the displacement body, the settable liquid has a sufficiently high viscosity to be drawn in stable form at the desired production throughout without flowing more quickly than the drawing rate as a result of its own weight.
摘要:
In the method of making a monocrystalline or polycrystalline semiconductor material semiconductor raw material is introduced into a melting crucible and directionally solidified using a vertical gradient freeze method. The molten material trickles downward, so that the raw material that has not yet melted gradually slumps in the melting crucible. The semiconductor raw material is replenished from above onto a zone of semiconductor raw material which has not yet melted or is not completely melted to at least partly compensate for shrinkage of the raw material and to raise the filling level. To reduce the melting time and influence the thermal conditions in the system as little as possible, the semiconductor raw material to be replenished is heated to a temperature below its melting temperature and introduced into the crucible in the heated state.
摘要:
The invention relates to a method for producing a monocrystalline or polycrystalline semiconductor material by way of directional solidification, wherein lumpy semiconductor raw material is introduced into a melting crucible and melted therein and directionally solidified, in particular using the vertical gradient freeze method.In order to prevent contamination and damage, the semiconductor raw material is melted from the upper end of the melting crucible. The molten material trickles downward, so that semiconductor raw material which has not yet melted gradually slumps in the melting crucible. In this case, the additional semiconductor raw material is replenished to the melting crucible from above onto a zone of semiconductor raw material which has not yet melted or is not completely melted, in order at least partly to compensate for a volumetric shrinkage of the semiconductor raw material and to increase the filling level of the crucible.In order to reduce the melting-on time and to influence the thermal conditions in the system as little as possible, the semiconductor raw material to be replenished is heated by the purposeful introduction of heat to a temperature below the melting temperature of the semiconductor raw material and introduced into the container in the heated state.
摘要:
Method for creating and presenting layer images that are generated from a set of volume data, whereby the volume data are recorded with a tomographic recording device, for example with a “cone beam CT” device, and show the jaw area of a patient, whereby planning data are assigned to the volume data, and said planning data describe the position of an implant that is to be inserted into the jaw and that has an implant axis, whereby a coordinate system that is adapted to a panoramic curve or a panoramic surface is defined that is formed by the vectors u, v, and w that are orthogonal to one another, whereby for the creation and presentation of a layer image, a representational plane is selected that intersects an implant that is described by the planning data, whereby in a first case, the v vector is orthogonal to the panoramic surface and/or the panoramic curve, and the implant axis intersects in a reference point, whereby the reference point is selected as the origin of the coordinate system, whereby the w-vector that runs through the reference point is tilted in such a way that the implant axis lies in the v, w-plane, whereby the v, w-plane forms a first base plane and whereby a representational plane that is parallel to the first base plane is selected, whereby in a second case, the u vector intersects the implant axis in a reference point and is parallel to the tangent on the panoramic curve in the perpendicular point of the reference point to the panoramic curve, whereby the w-vector of the coordinate system is tilted in such a way that the implant axis lies in the u, w-plane, whereby the u, w-plane forms a second base plane and whereby a representational plane that is parallel to the second base plane is selected.
摘要:
The glass fiber for an optical amplifier has a matrix glass core, a first glass cladding, and a second glass cladding. The matrix glass core has a composition, in mol %, of Bi2O3, 30-60; SiO2, 0.5-40; B2O3, 0.5-40; Al2O3, 0-30; Ga2O3, 0-20; Ge2O3, 0-25 ; La2O3, 0-15; Nb2O5, 0-10; SnO2, 0-30; alkali metal oxides, 0-40; and Er2O3, 0.05-8. The glass claddings have the same composition as the core, except that a transition metal compound is included as an absorbent. The refraction index of the matrix glass is > about 1.85, the refraction index of the first glass cladding is less than that of the core, and the refraction index of the second glass cladding is higher than that of the first.
摘要:
The double crucible for a glass drawing method has a heatable outer crucible (1) and an inner crucible (2) surrounded by the outer crucible (1), which is heatable separately from the outer crucible (1). Both crucibles (1,2) have an outlet nozzle (1a, 2a) for the glass to be drawn. To make glass fibers from heavy metal oxide glass (HMO-glass) with higher quality and comparatively simple crucible features, the outlet nozzle (1a) of the outer crucible (1) extends a certain distance beyond the outlet nozzle (2a) of the inner crucible (2). Surfaces of the outlet nozzles coming in contact with the glass melt are polished and are provided on a material, which has a reducing action on heavy metal glass in the melt in all cases. These surfaces also have sufficient mechanical strength for and chemical inertness to heavy metal oxide glass.
摘要:
The invention relates to a method and an apparatus for producing optical glass elements, in particular optical prisms or optical rod lenses, using a drawing process. The geometry of the glass strand which is to be produced is controlled by means of cooling or heating elements positioned at least around portions of the periphery or longitudinal axis of the glass strand, inside or outside the heating apparatus.
摘要:
The glass fiber for an optical amplifier has a glass core, a first glass cladding, and a second glass cladding. The core has a composition, in mol %, of Bi2O3, 30-60; SiO2, 0.5-40; B2O3, 0.5-40; Al2O3, 0-30; Ga2O3, 0-20; Ge2O3, 0-25; La2O3, 0-15; Nb2O5, 0-10; SnO2, 0-30; alkali metal oxides, 0-40; and Er2O3, 0.05-8. The process for making the glass fiber includes first making a preform consisting of the core and the first glass cladding by drawing from a double crucible. Then the second glass cladding is formed around the preform by a rod-in-tube process. The glass claddings have a composition that includes a transition metal compound as an absorbent.
摘要:
The method of making globular or spherical bodies of optical quality includes filling receptacles (2) in a heat-resistant support (3) made of a porous material with glass gobs (1); conducting gas through the heat-resistant support so that a gas flow (4) passes through the support in a direction (14) opposite to a direction in which gravity acts; heating the heat-resistant support (3) to a temperature at which the glass gobs (1) have a viscosity of up to about 106 poise; maintaining the support (3) at this temperature for a predetermined time interval; and then cooling the support (3) to ambient temperature while continuing to provide the gas flow (4) through the support (3).
摘要:
The invention relates to glass tubes for technical applications, especially for electrical or magnetic components, such as reed switches for example. According to a first embodiment, the glass tube has an inner bore (23) and at least one cross-sectional constriction (X) whereby the relationship applicable between the respective cross-sectional constriction (X) and the diameter (d) of the circumference of inner bore (23) is: x greater than or equal to 0.02*d, more preferably x greater than or equal to 0.1*d. According to a further embodiment, the glass tube has at least one inner bore with at least one inner edge, wherein the radius of curvature of the respective inner edge is less than or equal to 0.1 mm and preferably less than or equal to 0.03 mm. The glass tube is used as a preform for a subsequent redrawing process. The preform is formed by casting a molten glass into a shaft in the interior of which is located a shaping means for defining the inner bore. In this case a gas cushion prevents direct contact of the molten glass with the inner circumferential wall of the shaft and/or the outer circumferential wall of the shaping means.