Abstract: An optical fiber having an intense polarization plane maintenability is constructed of an optical waveguide having a circular core and a circular cladding, a jacket formed on the outer circumference of the optical waveguide and having an elliptical outer circumference, and a supporting portion formed on the jacket.In order to fabricate the above-specified optical fiber, a preformed rod therefor is prepared by forming the inner wall of an silica glass tube with the jacket and the optical waveguide made of such materials as satisfy a relationship of c.sub.2 /a.gtoreq.200/(100-.gamma.)-1, wherein: letter .gamma. stands for the ellipticity of the outer circumference of the aforementioned jacket; letter c.sub.2 stands for the minor axis of an ellipse; and letter a stands for the radius of the circular optical waveguide, and by subsequently collapsing the aforementioned silica glass tube while having its internal pressure made lower than the atmospheric pressure by 1 to 20 mmH.sub.2 O.

Abstract: A process for the fabrication of integrated circuits, wherein the interlevel dielectric material is partially etched back prior to reflow. This provides a pre-reflow profile which prevents filament problems in subsequently-patterned conductor levels, and which also avoids cracking of the interlevel dielectric during reflow.

Abstract: A low-pressure mercury vapor discharge lamp having a very satisfactory color rendition, (R(a,8).gtoreq.85), a color temperature of 2300-3300 K and a color point on or near the Planckian curve. The lamp is provided with a luminescent layer comprising:a. a luminescent alkaline earth metal halophosphate activated by Sb.sup.3+ and Mn.sup.2+ having a color temperature of 2900-5000 K;b. a luminescent material activated by Eu.sup.2+ with an emission maximum van 470-500 nm and a half-value width of at most 90 nm, andc. a luminescent rare earth metal metaborate activated by Ce.sup.3+ and Mn.sup.2+, having a fundamental lattice Ln(Mg,Zn,Cd) B.sub.5 O.sub.10, in which Ln represents the elements Y, La and/or Gd, which borate has red Mn.sup.2+ emission.Further, the lamp is provided with means for absorbing blue radiation having wavelengths below 480 nm. Preferably, the luminescent layer further contains:d. a luminescent material activated by Tb.sup.3+ which exhibits green Tb.sup.3+ emission.

Abstract: While collapsing the central duct in hollow glass optical fiber preforms, an etchant consisting of a mixture of oxygen and a fluorocarbon compound from the group C.sub.2 F.sub.6, C.sub.3 F.sub.8 and N-C.sub.4 F.sub.10 is passed through the duct. In particular, the etchant is passed through the duct only when the duct's diameter is 1 mm or smaller. The resulting solid preforms and optical fibers drawn therefrom do not have a central dip in the refractive index profile.

Abstract: In the process for applying a protective plastic coating to a glass optical waveguide fiber by the application of a curable liquid coating material thereto and the subsequent curing of the liquid coating to a protective plastic layer, the surface of the glass optical fiber is conditioned prior to the application of the liquid coating material thereto by replacing air adjacent the fiber surface with a selected gas preferably exhibiting high solubility in the liquid coating composition and resisting bubble formation in the liquid coating layer as it is formed.

Abstract: A method of producing a joint between a beta-alumina electrolyte tube and alpha-alumina flange with a glass bonding agent in a solid annular bead form devoid of additives such as a coupling agent or the like capable of being heated when subjected to microwave energy which comprises utilizing in the heating step a source of microwave energy rather than a gas flame or electrical resistance heat source so as to heat the beta-alumina tube by microwave energy for a time period sufficient to enable the heat generated in the beta-alumina tube to be conducted to glass bead and the alpha-alumina flange and heat the glass bead to a temperature above the glass deformation point, and allowing the tube to cool to solidify the glass bead in intimately penetrating relation to the surfaces of the beta-alumina tube and alpha-alumina flange engaged thereby so that the glass forms a bond between the beta-alumina tube and the alpha-alumina flange characterized by a fusion of the glass within the engaged beta-alumina and alpha-al

Abstract: Method and apparatus is set forth for cooling glass molding equipment such that the thermal considerations of the equipment design and the mechanical considerations thereof are uncoupled. The uncoupling of the thermal and mechanical considerations facilitates the utilization of the forming member at varying production speeds, since different cooling inserts, having the desired thermal characteristics for the particular production speed utilized, may be provided within the forming member. In order to effect good heat transfer between the forming member and the cooling insert, a gap is provided which is substantially filled with a low melting metal alloy.

Abstract: Layered glass products such as multilayer glass rods or fibers are formed in a preferably continuous process wherein at least two component glasses are supplied to an annular mixing zone wherein relative movement of the annular surfaces produces spiral layering of the glasses and the formation of a glass product stream having a preselected gradient in composition and glass properties across a diameter thereof.

Abstract: The mould of the mould arrangement comprises a bottom plate and two side portions which are movable to a first position in which they engage one another and the bottom plate to define a mould cavity and to a separated position. The side portions define cooling passages having entrances in bottom surfaces of the side portions and the bottom plate has at least one plenum chamber formed therein which has exits which, when the side portions are in their first position, communicate with cooling passage entrances so that air blown into the plenum chamber passes through the cooling passages. A bottom plate for the arrangement is also disclosed.

Abstract: A method and apparatus for preheating particulate glass batch comprises a rotatable drum for mixing batch with heat transfer media in a heat transfer relationship, means for directing the heated batch from the container to a glass melting furnace, means for venting gases and gas-borne particulate matter from the drum, means for separating a selected portion of the particulate matter from the vented gases, and means for directing the separated particulate matter into the glass melting furnace.

Abstract: A method for reducing the amount of particles which become airborne during either or both the dismantling and moving of structures wherein a foam is sprayed on the structures prior to either or both the dismantling and moving of such structures.

Abstract: In the P.C.V.D. process in principal the quartz tube need not be rotated during the deposition of the glass layers. However it has been found in practice that an improvement in the quality of the glass fibers can be obtained if the quartz tube is rotated regularly over an angle of 360.degree./n. n is preferably equal to an integer from 2 to 12.

Abstract: A process for producing a transparent glass product having a refractive index gradient by the molecular stuffing method is described. A thallium compound is used as a dopant and, after a concentration gradient of the thallium dopant is formed, the porous glass product is heated up to the temperature region of 350.degree. to 550.degree. C. at a temperature-rising rate of 25.degree. to 150.degree. C./hour in a reducing gas atmosphere and then heat treated above 550.degree. C. in an inert gas atmosphere to collapse micropores in the porous glass product, thereby obtaining a glass product having a refractive index gradient which is transparent and free of light-scattering and coloration. The glass product is suitable as materials (preforms) for optical fibers or materials for rod-shaped lenses, particularly rod-shaped microlenses for microlens arrays and microlenses for coupling an optical fiber and a light source.

Abstract: A glassware molding machine having a parison molding portion and a container body molding portion includes a spray apparatus with a spray head that is operatively attached to a spray spindle. Vaporized lubricant is sprayed radially outward from the spray head while the spray head is rotated and moved upwardly through the molding cavity. The automatic cycle of the glassware molding machine is interrupted while the mold halves are closed so that the lubricant is not deposited onto mating surfaces of the mold halves; a barrier of air is provided to prevent lubricant from being deposited onto the parison plunger; a collection system is provided to capture exhaust materials from the application of lubricant to the hot mold surfaces; and provision is made for depositing a heavier layer of lubricant, or a different lubricant, on a selected surface of the molding cavity.

Abstract: A method for manufacturing hollow core optical fibers is disclosed comprising continuously feeding a glass rod of the desired cladding composition into a high temperature furnace with the rod in line contact with the inner surface of the glass tube. The glass transition temperature of the rod is substantially lower than the glass transition temperature of the glass tube. The glass rod composition is uniformly distributed on the glass tube inner wall as it enters the furnace hot zone. The ratio of the rod diameter to the glass tube inner diameter and the drawing temperature determine the coating thickness of the glass cladding on the inner surface of the glass tube. As the coated tube is passed through the furnace hot zone peak, the optical fiber is drawn. The rod and tube feed rate, the drawing temperature of the rod and glass tube and the drawing rate of the coated glass tube are selected to yield a hollow core optical fiber, with preselected interior and exterior diameters.

Abstract: There is disclosed use of a plasma for consolidating and/or dehydrating a glass soot preform. A plasma is struck in a vessel and the preform is inserted thereinto for effecting treatment of the preform.

Abstract: Electrons are copiously emitted by a device comprising a loop-shaped filament made of lanthanum hexaboride. The filament is directly heated by an electrical current produced along the filament by a power supply connected to the terminal legs of the filament. To produce a filament, a diamond saw or the like is used to cut a slice from a bar made of lanthanum hexaboride. The diamond saw is then used to cut the slice into the shape of a loop which may be generally rectangular, U-shaped, hairpin-shaped, zigzag-shaped, or generally circular. The filaments provide high electron emission at a relatively low operating temperature, such as 1600.degree. C. To achieve uniform heating, the filament is formed with a cross section which is tapered between the opposite ends of the filament to compensate for non-uniform current distribution along the filament due to the emission of electrons from the filament.

Abstract: A gob distributor has two scoops, one arranged to be aligned with some sections of the machine to deliver gobs thereto and the other arranged to be so aligned with other sections of the machine. Turning means is operable to turn the scoops to bring them to desired orientations for alignment with their respective sections and moving means is operable to move the distributor to bring either of the scoops below a feeder orifice from which gobs are supplied. In this way, the scoops share the distribution function. If more than one gob is to be supplied simultaneously, further pairs of scoops can be used.

Abstract: A nozzle or nozzles for spraying cooling water are disposed at the lower end of a slag suction path. A cooling water down-flow passage is provided on the outer periphery of an inner tube which constitutes a slag suction path. A water sump is provided below the cooling water down-flow passage, the water sump being located lower than the each nozzle. A lower end opening of the cooling water down-flow passage is disposed lower than the each nozzle and is submerged in water in the water sump. The cooling water down-flow passage, except the lower end opening, is adapted to be closed up. When the cooling water down-flow passage is closed up, water in the passage is stopped by atmospheric pressure acting upon the surface of the water in the water sump, so that it is prevented from flowing down.

Abstract: A highly efficient, AC-excited, blue light-emitting phosphor for solid-state thin-film electro-luminescent (TFEL) devices is comprised of strontium sulphide (SrS) host material doped with cerium fluoride (CeF.sub.3) acting as an emitter providing a source of photons. The blue SrS:CeF.sub.3 phosphor is about one hundred times brighter than the brightest zinc sulphide/thulium fluoride (ZnS:TmF.sub.3) blue phosphor heretofore known. To increase brightness level, at some loss of energy efficiency, electron-injection layers of zinc sulfide (ZnS) are placed on either side of the SrS:CeF.sub.3 layer in the TFEL device.