Abstract: An optical fiber comprising core glass having therearound a cladding comprising fluorine-containing quartz glass and a process for producing the same are disclosed. Said cladding is composed of an inner portion having a prescribed thickness and a constant fluorine content through its thickness and an outer portion having its fluorine content being gradually decreased in a radial direction so that its outermost surface has a fluorine content of about 0.7% by weight or less relative to SiO.sub.2.

Abstract: A friction material having particular use in brake pads for motor vehicles. The material includes iron powder as its chief constituent. In addition, the material contains phosphorous (P) of 0.02% or more of sulfur (S) of 0.02% or more or combined P and S of 0.03% or more.

Abstract: A method for producing a glass preform for an optical fiber comprising flame hydrolyzing a glass raw material in an oxyhydrogen flame to form glass fine particles, depositing the glass fine particles on a seed member to produce a solid or hollow cylindrical soot preform, dehydrating by holding the whole soot preform in an atmosphere containing a dehydrating agent kept at such temperature for such period of time that the diameter of the soot preform shrinks by at least 20%, and heating and sintering the dehydrated soot preform by introducing it from its one end in an atmosphere of a pure inert gas to produce a glass preform having a uniform distribution of refractive index along its length, from which glass preform, an optical fiber having attenuation of light transmission as low as 1 dB/km or less at a wavelength of 1.30 micrometer is fabricated.

Abstract: A method for measuring certain geometrical properties of an optical fiber wherein the coating is removed from adjacent one end of the fiber, a high intensity light source is focused at the bare fiber and coating interface in order to couple scattered light into the optical fiber cladding and the intensity distribution of the transmitted light at the end face of optical fiber is analyzed. In this fashion nonuniformities on the end face of the optical fiber will not substantially affect the accuracy of measurements of geometrical properties of the cladding region of the optical fiber.

Abstract: A non-metallic self-supporting aerial optical cable is comprised of a suspension wire and optical cable which are made of non-metallic material and have non-metallic sheaths. The optical cable and suspension wire are maintained substantially parallel by a number of spaced apart connecting members. The optical cable is allowed to sag between the connecting members in order to withstand tensile forces which result from wind, snow and the like.

Abstract: A method of making a holographic light guide comprising, in sequence, a substrate, a light guiding layer and a holographic recording layer that partially replaces the light guiding layer is disclosed. The substrate is made of a first bismuth sillenite group substance. The light guiding layer is made of a second bismuth sillenite group substance that has a higher refractive index than the first bismuth sillenite group substance and absorbs little of the light being guided. The holographic recording layer is made of a third bismuth sillenite group substance that has a higher refractive index than the first bismuth sillenite group substance and has a degree of photosensitivity.

Abstract: A gas reaction apparatus for manufacturing base material of optical fiber and a multi-wall pipe type burner for the gas reaction apparatus. The gas reaction apparatus includes a mechanism which heats or heat insulates at least one of gas passages of the burner for gaseous raw material of optical fiber so as to set a saturated vapor pressure of whole kinds of the gaseous raw material higher than a partial pressure of raw material of optical fiber in the gaseous raw material when the gaseous raw material is fed through the one of the gas passages.

Abstract: A warning device for an automobile having a number of lights that are illuminated in response to opening of a compartment in which the light is positioned, such as an engine compartment trouble light, interior courtesy lights and/or a trunk light. In accordance with the invention, each light is served by a conductor that is contained within a wire harness. An arrangement is provided wherein the illuminated condition of the light is changed in response to a failure condition of a device served by the same wire harness so as to provide a simplified warning system.

Abstract: A flexible membrane-type rising and falling weir is anchored at the curved crest of a concrete structure in a body of water. A drain discharge pipe has an opening positioned at the lowest portion of the interior of the envelope to provide complete discharge of water accumulated so that the weir deflates completely to permit smooth flow of water over it.

Abstract: A prestressing steel material for use with concrete that is prestressed by posttensioning is disclosed. Said steel material is unbonded from the concrete. The prestressing steel material is composed of a steel member sheathed with a foamed synthetic resin tube. The wall thickness of the synthetic resin tube is at least 300 microns, more preferably, more than 500 microns. In the case that the steel member is a strand composed of a plurality of twisted steel wires, the spiral grooves of the strand are first filled with a resin and the strand together with the resin sheathed with the foamed synthetic resin tube.

Abstract: A method for producing an aluminum-stabilized superconducting wire is dislcosed herein, which comprises alternately winding superconducting elementary wires and high purity wires around a core, such as an electrically insulated copper wire core, impregnating the entire wire arrangement with solder to bind the wires together and subsequently forming or drawing the wire arrangement to increase the adhesion between the wires. In another embodiment, the thus-impregnated wire arrangement is subjected to a heat treatment to recover the residual resistance ratio of the aluminum. The impregnated wire arrangement is characterized by having a high mechanical toughness and improved electrical contact for greater electrical stability.

Abstract: An electrically-conductive sintered compact of silicon nitride which is machinable by electrical discharge machining and a process to produce the same. TiN and/or TiC powder is added to a powder of silicon nitride in an amount 15-40% by volume to act as a conductivity-supplying agent while 0.01-3.0% by volume MgO and/or Al.sub.2 O.sub.3 powder is added as a sintering assistant. The mixed powders are then preformed in a desired shape and sintered in a nonoxidizing environment at 1,600.degree. C.-2,000.degree. C. to obtain a compact of silicon-nitride machinable by electrical discharge machining due to its electrical conductivity being at least 1 S.multidot.cm.sup.-1.

Abstract: A method for producing carbon fiber reinforced carbon material comprisingadhering carbonaceous fine powder to a resinous carrier which can be ionized in a liquid,dispersing the carrier carrying the carbonaceous fine powder in a liquid,placing a carbon fiber substrate and an opposite electrode in the formed dispersion,applying DC voltage between the substrate and the opposite electrode to deposit the carrier carrying the carbonaceous fine powder on the substrate by electrophoresis,heating and/or drying the carbon fiber-carbonaceous fine powder-carrier complex, andcalcining the complex to form carbon fiber reinforced carbon material.

Abstract: A novel thin film magnetic head is provided characterized by the use of a new substrate material excellent in mechanical property as well as machinability. This substrate is composed of a ceramic compact comprising 4 to 45% by volume of Component A, 55 to 96% by volume of Component B and at most 3% by volume of unavoidable impurities:Component A: at least one member selected from the group consisting of carbides, nitrides, carbonitrides, carboxides, oxynitrides and carboxynitrides of Group IVa, Va and VIa elements of Periodic Table and mixtures or solid solutions thereof.Component B: ZrO.sub.2 consisting of at least 70% by weight of tetragonal and/or cubic system and the balance of monoclinic system, in which at least one member selected from the group consisting of oxides of Group IIIa elements of Periodic Table, CaO and MgO, and mixtures thereof is dissolved to form a solid solution.

Abstract: A rotary gear pump having inner and outer gear rotors of the type having respective inner and outer surfaces whose cross sections are determined utilizing the trochoidal curve, the inner gear rotor having trochoidal dimensions which either eliminate or diminish to a negligible amount the edge portion of the teeth which cause excessive wear, noise or inefficiency. In one embodiment of the invention, the dimensions of the inner gear rotor are such that C/K.sub.0 .ltoreq.1 or f.sub.c /K.sub.1 .ltoreq.1.1, where C is the rotary path diameter, K.sub.0 =(A/B+1).times..vertline.B-2e.vertline., K.sub.1 =(n+1).times..vertline.1-2f.sub.e .vertline., A is the diameter of the base circle, B is the diameter of the rolling circle, e is the eccentricity, n=A/B, f.sub.e =e/B, and f.sub.c =C/B. In accordance with a second embodiment of the invention, a comparable result can be obtained provided that the number of teeth on the inner gear rotor is equal to an integer closest to the ratio d.sub.4 /2e, wherein d.sub.

Abstract: A functional elastomer in which a viologen unit is introduced into a principal polymeric chain through cationic polymerization by using a bifunctional initiator, said elastomer being represented by the formula ##STR1## wherein X represents polyether and A represents an anion.

Abstract: A glass fiber for optical transmission comprising a glass fiber having provided thereon a first coating layer of a hardened resin and a second fluorine-containing resin layer formed by extrusion molding is disclosed. At least one of the first and second layers contains an adsorbable solid powder which is capable of adsorbing fluorine gas and/or hydrofluoric acid generated from the fluorine-containing resin during the extrusion molding. The glass fiber has an improved mechanical strength without adversely affecting transmission properties of the glass fiber.

Abstract: A method for producing a glass preform comprising flame hydrolyzing a glass raw material in an oxyhydrogen flame to form glass fine particles of quartz, depositing the glass fine particles on a seed member to produce a solid or hollow cylindrical soot preform at least of a part of which contains GeO.sub.2, and heating and sintering the soot preform by introducing it in an atmosphere comprising an inert gas at least a part of which is kept at a temperature not lower than 1,600.degree. C. at an introducing rate not smaller than 3 mm/min, from the glass preform produced by which method, an optical fiber having longitudinally homogeneous composition and low attenuation of light transmission is fabricated.

Abstract: A method of fitting a rubber stopper for a water-proof connector terminal onto an end portion of an electric wire includes the steps of: successively feeding a group of rubber stoppers aligned in a row in a state wherein each of the rubber stoppers has its longitudinal axis extending vertically; transferring each of the rubber stoppers into a stopper housing portion; retaining the electric wire disposed on an imaginary line passing through the center of the stopper housing portion; and press-fitting the wire into the rubber stopper, whereby the rubber stoppers are successively and continuously fitted on the respective wires. Also disclosed is an apparatus which may be suitably employed to carry out the above-described method. The apparatus includes an aligned stopper successively feeding section, a stopper transfer section, a rotary conveyor section, and a wire press-fitting section.