Abstract: The present invention is directed to a method for developing a bond having a shear strength in excess of 1200 psi between dental cements and dental appliances fashioned from glass-ceramic materials. The inventive method consists of contacting the fitting surface of the appliance with an etchant in flowable gel form at a temperature below about 150.degree. F., while protecting the exterior surface of the appliance. Subsequently, a silane solution followed by a dental cement is applied to the etched surface and cured in place.

Abstract: An electron tube comprising a window having a radiation-sensitive layer. The window is laid on a bearing surface of an envelope normal to the tube axis. There is no sealing material in the seam between the bearing surface and the window. The seam is sealed hermetically by a mass of indium or an indium alloy in which a metal wire is embedded along the circumference of the seam. The wire can be soldered with indium or an indium alloy. The seal is made by locally melting the indium or the indium alloy by a heated ultrasonically vibrating heat transfer member. The heat transfer member traverses the circumference of the seam.

Abstract: A bundle of optical fibers each covered by an acid-soluble borosilicate glass is treated with an acid solution, with an alkali solution, and then with an acid solution to completely remove the acid-soluble glass from the middle portion between the end portions of the optical fiber bundle. A plastic material is charged into the interstices among the fibers at the boundary portions between the middle portion and the end portions. These interstices are free of any insoluble residue of the acid-soluble glass. A reinforcement is formed around the periphery of at least a part of the boundary portions by covering the periphery with a flexible plastic material or by winding a linear member around the periphery.

Abstract: Incorporation of fluorine into a porous silica body, such as an unsintered body produced by a sol-gel method, by VAD or OVPO, reduces or eliminates bubble or pore formation upon re-heating of the glass formed by sintering of the porous material. Effective fluorine concentrations are between 0.01 and 5% by weight. The invention can be used advantageously in producing preforms and optical fiber.

Abstract: A device for transferring the energy emitted by a high power laser onto a target characterized in that it comprises two guides of optical fibre having step index refraction distribution and at least a plastic material coating. The first guide, stiffly coupled to the laser source, is a variable section fibre with an input face of larger diameter. Guide is the second one by a uniform or variable section fibre with a larger diameter near the output terminal. The two guides are joined by a low leakage optical fibre connector, and between them an adapter can be interposed if the output section of the first guide of fibre does not coincide with the input section of the second guide of fibre. The variable section fibre can be drawn from a pre-moulded or melted material, with the speed controlled by an electronic circuit. Different kinds of pots can be utilized in order to obtain the fibre plastic coating.

Abstract: A low loss fiber optic coupler is fabricated by forming a coupler preform having a plurality of spaced glass cores extending longitudinally through a matrix of glass having a refractive index lower than that of the cores. The coupler preform is heated and stretched by first pulling means to form a glass rod which is drawn by second pulling means past an intermittant source of localized heat. When the localized heat source is turned on, the second pulling means draws the rod downwardly at a rate faster than the first pulling means. Since the rod is softened by the localized heat source, a necked-down coupling region is formed. The rod is severed to form a plurality of coupler units. When an end of a unit is immersed in acid, the matrix glass dissolves, thereby leaving the unit cores and surrounding etch-resistant cladding glass protruding from the newly formed endface of the unit.

Abstract: A cooling arrangement for a forming tool of a machine for forming molten glass or other thermoplastic materials, wherein the forming tool is coolable by a pressure fluid and turnable about a first pivoting axle, includes at least one stationary supply conduit having an outlet opening, a pressure distributing device for the forming tool turnable relative to said supply conduit about the first pivoting axle, and a connecting conduit arranged to connect each supply conduit with the pressure fluid distributing device and having an articulated conduit component turnable about a second pivoting axle which is fixed relative to the pressure fluid distributing device and is parallel to the first pivoting axle, the articulated conduit component having an inlet opening which is in a constant communication with the outlet opening of the supply conduit, the articulated conduit component being displaceable relative to the supply conduit in a displacement plane normal to the pivoting axles.

Abstract: The movable side portions of a mould of a cyclicly operating glassware forming machine have cooling passages passing upwardly therein from an entrance in a bottom surface of the side portion. A plenum chamber is formed beneath the side portions and has upwardly opening exits which communicate with the entrances of the cooling passages when the side portions are stationary in either an open or a closed position thereof so that cooling air can pass into the cooling passages. In this way, each cooling passage can be supplied with air at substantially the same pressure and low pressure air can be used.

Abstract: This relates to improvements in drives for shears, particularly shears for severing gobs from a glass runner. All of the drives incorporate a drive pinion for reciprocating racks which are secured to slides of the shear. The pinion is rotated first in one direction and then in the opposite direction to cause the blades of the shear to first move together and shear a gob, and then move back to the original position. Suitable reversing motors may be utilized, including an electrical servomotor or suitable hydraulic motor. On the other hand, the drive motor may be of the unidirectional type and an oscillating drive member may be incorporated in the drive system for converting the one-directional drive of the motor to an oscillating or reversing output. In addition, the drive of the pinion may be supplemented by a double-acting air motor which is connected to one of the racks.

Abstract: Improved quartz barrier means for drawing dendritic silicon web from a silicon melt forms within the quartz crucible a silicon melt replenishment section and a web drawing section. To permit the molten silicon to flow from the melt replenishment section into the web drawing section, aperture means are provided in the form of cut-out sections in the lateral edges of the barrier means. The position of the aperture means above the bottom of the crucible insures an adequate pool of molten silicon to flow into the web drawing section. The position of the aperture means beneath the top level of the molten silicon insures that no unmelted silicon floating on the top of silicon in the replenishment section passes into the web drawing section. The position of the apertures next to the heated side walls of the crucible insure that the melted silicon is heated to an optimum temperature upon passing into the web drawing section.

Abstract: An automatic machine for welding optical fibers end-to-end comprises a first plate (1) for supporting a first or "reference" fiber (2) and a second plate (5) for supporting a second or "moving" fiber (6). The second plate can be translated along Ox and Oy axes in a plane perpendicular to the axes of the fibers. The ends of the fibers are illuminated by light sources (30, 31), optical systems make images thereof, and optical pick-ups (12, 13, 18, 19) located at the image points provide optical signals representative of the positions of the optical fibers relative to each of said Ox and Oy axes. These signals are converted into electrical signals and are compared by electronic comparators (15, 21) which deliver corresponding error signals to control means (17, 23, 24) for moving the second plate until the moving fiber is in alignment with the reference fiber.

Abstract: Method of producing metal interconnections in a semiconductor integrated circuit structure of a body of silicon coated with silicon dioxide having openings therein exposing contact regions to underlying silicon. A thick layer of an insulating or dielectric material, for example, polymide, is deposited on the body. Grooves in the pattern of the desired interconnections are etched through the thick insulating layer to the underlying silicon dioxide and contact regions. Metal is deposited to fill the grooves and cover the thick layer of insulating material. Excess metal is removed to form a planar surface exposing the surface of the thick insulating layer with the grooves containing metal to provide electrical connections between contact regions.

Abstract: On a support which supports a light-emitting semiconductor device there is arranged a cap which is hermetically sealed to the support. In the cap there is provided a transparent plate, an inner layer of which facing the semiconductor device consists of a material having a high refractive index (>1.7). On the outer side of the plate there is provided a layer of photosensitive lacquer which is exposed to the light emitted by the semiconductor device. After development of the layer of lacquer, only the exposed part which is situated opposite the semiconductor device remains. This part is heated to the melting point, thus forming a droplet of lacquer, after which the outer layer of the plate and the droplet of lacquer are removed by way of a non-selective etching method, so that a lens which is situated opposite the semiconductor device and a flat window which surrounds the lens are automatically formed at the same time.

Abstract: The present invention discloses an apparatus for deicing the exterior of a railway vehicle that uses heated air which is blown at a railway vehicle at 5-35 m/sec and subsequently recycled for reblowing.

Abstract: A rack aligning fixture for aligning the racks of a rack and pinion mechanism is described. The rack alignment fixture permits the aligning of rack teeth faces of a rack and pinion mechanism at the time of assembly without having to provide additional machining of the individual parts in order to maintain the racks parallel with each other for proper mating of the rack teeth with the pinion gear teeth.

Abstract: There are disclosed an optical fiber junction device and a method of making the same. The method comprises the steps of providing a central inner pipe or rod of glass, arranging a plurality of optical fibers around the inner pipe or rod, and externally heating the optical fibers and the central inner pipe to form a thermally fused assembly having cores of a sectorial cross section. The inner pipe may include a tapered portion having a reduced diameter. The optical fibers may comprise optical fiber junction units each composed of a plurality of optical fibers.

Abstract: The blowhead arrangement comprises a blowhead (18) and a support (10,12,16) therefor. The support defines a passage (50,52,54,56,58,60) through which a first supply of air under pressure can be supplied to the blowhead (18) and a passage (70,74) through which a second supply of air under pressure can be supplied to the blowhead. The first of the supplies of air is used to blow a glass parison in a mould cavity to the shape of the cavity when the blowhead (18) is in position on the glass parison. The second supply is used to cool the finish of the parison by impinging on the finish from openings (90) in the blowhead.

Abstract: A method of fabricating an optical waveguide comprising a plane substrate made of a material having a relatively low refractive index, a plane light propagation layer made of a material having a higher refractive index than the substrate, inserted between two strips of a material having a lower refractive index than its own, and a plane light confining layer of a material having a lower refractive index than the propagation layer. At least one of the layer, meaning either the propagation or the confinement layer, is obtained by causing to circulate in a tube of pure silica the vapors of a gaseous compound of silicon transformable into silica and of a gaseous compound of a doping agent transformable into one of its own oxides and heating said vapors sufficiently to obtain the deposit of a layer of doped silica having a refractive index different from that of the pure silica.

Abstract: An improved method of manufacturing an optical fibre by vapor phase deposition of layers of cladding and core material for an optical fibre on the inside of a tubular substrate, followed by heating of the tube to cause it to collapse into a preform and drawing of the preform to form the fibre, includes performing the collapse with the introduction of chlorine gas acting as a drying agent. An alternative to chlorine gas is a vapor which decomposes in situ to yield chlorine without producing a solid deposit.

Abstract: The apparatus for manufacturing the ink jet glass tubes includes a vertical mandrel which receives the tubes one at a time from a feeder and rotates them relative to a pair of gas nozzles for their heating. The tube is heated in an axially limited intermediary zone so as to form an hour-glass shaped profile.The profile of the tube is scanned by a television camera which generates two signals indicative of the internal diameter. These are compared electronically with a stored indication of the desired diameter and the two nozzles are rotated into an inactive position when this diameter is reached. The tube is cut along a plane so as to make the profile of the nozzle coincident with a reference profile by a device including an optical device connected to a cutting wheel to permit comparison of the hour-glass profile of the element with the reference profile. The severed end of the tube is then lapped and covered with a non-wettable material.