Abstract: A method for producing an optical multiple fiber unit wherein a multiplicity of optical fibers are fused together with each other and each optical fiber has a core made of pure silica glass and a cladding layer made of silica glass containing a dopant and disposed on the core, by bundling a multiplicity of preforms corresponding to the optical fibers and drawing the bundle at a high temperture using the optical fiber preforms, preforms having a three-layer construction wherein a support layer made of a silica glass having a drawable temperture of at least 1,800.degree. C. is further disposed on the cladding layer, and drawing the bundle of the preforms to give a multiple fiber wherein the support layer of each optical fiber has a thickness of 0.01 to 1 .mu.m, in order to produce a multiple fiber in which the cladding layer of each optical fiber has a sufficient thickness to fulfill the function as a cladding layer and which has an excellent image-transmitting capacity.

Abstract: The present invention relates to a connector for optical fiber used as optical communication parts, in particular to a ferrule which is one member of a plug side of the connector, a pointed end portion of the ferrule being partially cut off, and the optical fiber being inserted and fixed into the ferrule, the terminal treatment of the optical fiber is practiced by injuring the circumferential surface of the pointed end portion of the optical fiber and by cleaving the pointed end portion of the optical fiber.

Abstract: This invention relates to a connector for optical fiber used for optical communication parts, especially to a plug of the connector, comprising an inner tube into which an endportion of an optical fiber cord, whose cover is peeled off, is inserted and which is formed with axial slittings; and an outer tube being fitted onto the inner tube and made of a solid material, the inner tube being reduced in diameter at the portion having the slittings, thereby fixing the optical fiber thereto.

Abstract: A shielding article assembled by piling a plurality of multilayer sheets and fastening the sheets at one or both end portions, the multilayer sheet comprising an aluminium layer and a lead layer, wherein the thickness of the aluminium layer, the lead layer and the multilayer sheet are 10 to 100 .mu.m, twice the aluminium layer and 50 to 400 .mu.m, respectively. The shielding article is useful for shielding radioactive rays or sound and has excellent mechanical properties and heat resistance.

Abstract: It is disclosed that a metal cored board which comprises an electrically conductive layer whose one surface at least composed of a hardly oxidizable metal, an insulating organic polymer layer baked on the surface of the hardly oxidizable metal, and a metal core adhered on the insulating organic polymer layer, and a method for manufacturing a metal cored board, which comprises a step to coat the surface of a hardly oxidizable metal layer of an electrically conductive metal foil with an insulating varnish, a step to bake a layer of the varnish, and a step to adhere a metal core on the baked varnish layer.

Abstract: A connector for a high energy beam, which is provided with a sleeve fitted on an optical fiber and having an optical fiber support portion of an inner diameter about equal to a diameter of the optical fiber and a larger diameter portion positioned ahead of the optical fiber support portion and having an inner diameter larger than the diameter of the optical fiber so as to form a gap around the optical fiber and in a proper length from the end face of the optical fiber. The optical fiber support portion is formed of a heat resistant inorganic substance having a melting point of 1500.degree. C. or more, for example, a transparent substance, such as sapphire, or an opaque substance, such as aluminium oxide; the so-called fine ceramics. The connector of the present invention is free from burning, melting and diffusion of metallic material, and breakage of optical fiber when in use, thereby being easy to handle and high in quality and reliability and having a long life time.

Abstract: A fiber scope of the side-viewing type includes an image guide and two light guides disposed on both sides thereof in an objective part. The fiber scope is suitable for the observation of the surface of long articles assembled with narrow gaps therebetween as in an assembly of nuclear fuel rods in a nuclear reactor and a wide field of view can be secured even if an object to be observed stands within a point-blank range of an objective part. Also a plurality of long articles can be simultaneously observed by the fiber scope or the observation can be carried out while moving the fiber scope in the scanning direction. If the fiber scope is used in a radioactive environment, highly radiation resistant optical fibers are used.

Abstract: It is disclosed that a radiation-resistant optical conductor, such as an optical fiber for telecommunication, a multiple fiber for an image scope, and a light guide for illumination, which comprises a core composed of a pure silica glass which is prepared via an ultrahigh temperature of at least 3,000.degree. C. and has an OH group content of from 0.1 to 300 ppm, and a cladding layer formed on the core, and the cladding layer being composed of a silica glass which contains boron element and fluorine element as a dopant.

Abstract: An adhesive, suitable for joining cured polyolefin articles, comprising a water curable polyolefin having a melt index of from 0.1 to 20, and a method of joining cured polyolefin articles, especially cured polyethylene pipes, comprising a step to apply the above adhesive to the surface of the articles and a step to join both of the surfaces to each other with the melt of the adhesive.

Abstract: An optical fiber cable comprising a water blocking layer, an optical fiber disposed inside the water blocking layer and a water blocking material filling the space between the water blocking layer and the optical fiber, the water blocking material comprising a grease having a worked penetration of 85 to 475 as measured according to ASTM-D-712 at room temperature.

Abstract: An optical fiber cable comprising a water blocking layer, an optical fiber disposed inside the water blocking layer and a water blocking material filling the space between the water blocking layer and the optical fiber, the water blocking material having an apparent viscosity (as measured in accordance with JIS K 2220-1980, 5.15 at 40.degree. C., and a shear rate of 10 sec..sup.-1) of lower than 25,000 poise and also having a worked penetration (as measured in accordance with JIS K 2220-1980, 5.3 at 25.degree. C.) of 150 to 450.

Abstract: It is disclosed that a metal cored board which comprises a base metal core, an easily solderable metal plating layer formed on one surface of the base metal core, an electrically insulating layer formed on the another surface of the base metal core, and an electrically conductive metal layer formed on the electrically insulating layer, a method for manufacturing a metal cored board, which comprises a step to plate both surface of a base metal core with an easily solderable metal, a step to form an electrically insulating layer on one surface of the easily solderable metal plating layer, and a step to form an electrically conductive metal layer on the electrically insulating layer.

Abstract: An optical multiple fiber comprising a multiplicity of optical fibers which are fused together with each other, each optical fiber comprising a core made of pure silica glass and a cladding layer disposed on the core and made of a dopant-containing silica glass, characterized in that the thickness of the cladding layer satisfies the following equation (I):2 D.sub.1 .gtoreq.T.sub.1 .gtoreq.1.0 .mu.m. (I)wheren T.sub.1 is the thickness of the cladding layer in .mu.m. and D.sub.1 is the outer diameter of the core in .mu.m., in order to improve the image-transmitting capacity of the multiple fiber, including the sharpness and brightness of transmitted image.

Abstract: The invention relates to improvements in an image guide using optical silica glass fibers. The improved image guide has a light shielding and light absorbing thin layer formed on the periphery of an optical fiber bundle consisting of a multiplicity of optical fibers to prevent incidence of external light from the peripheral surface of the bundle and to absorb and remove any scattered light as it is transmitted to parts other than the core of each optical fiber, thereby providing improved picture quality.

Abstract: A tape for corrosion protection, in which a pressure sensitive adhesive is coated on one face of a plastic sheet, and pieces of galvanic sacrificial anode metal foil for cathodic protection are lined consecutively on a part of its adhesive face across less than the entire width of the plastic sheet. An object of this invention is to prevent corrosion by means of an effect of cathodic protection.

Abstract: A light weight, flexible environmental shield for shielding an object on one side of said shield from emissions from a source at the other side of said shield, said shield comprising a plurality of lead metal sheets stacked one upon another, each said lead metal sheet comprising a lead metal foil which is reinforced on one or both sides with an organic material having a resistance against the harmful source. The shield is useful for shielding an environment from a radioactive source and a harmful gas, and for soundinsulating.

Abstract: A shielding composition has an electromagnetic wave shielding property and also an injection molding property. The composition comprises at least one kind of embedding material selected from a group consisting of plasticized vinyl chloride and acrylonitrile-butadiene-styrene resin, and copper or copper alloy fiber having a diameter of 1-100 .mu.m and a length of 0.5-10 mm embedded in said embedding material. The amount of the fibers is 30-70% by weight of the total composition.

Abstract: Image display apparatus provided with an address converter aiding the apparatus in faithfully reproducing for display an optical image transmitted via an optical fiber bundle. The address converter is adapted to store information concerning the relation between the geometric address of the individual optical fibers at one end face of the optical fiber bundle and that at the other end face so as to permit conversion of one geometric address to the other. The small elements of an image transmitted through the individual optical fibers to the rear end of the bundle are rearranged in accordance with the geometric address of the fibers on the front end to complete an image conforming to the original transmitted image.

Abstract: An apparatus for electrically testing a multi-core cable comprises a pick-up unit (6) for picking up a core separately on a one by one basis from a group of cores (101) at one end of the cable (100). Conductor wires of all of a plurality of cores (101) of a cable are collectively rendered conductive by a contact grip (25, 25') at one end of all the conductor wires the opposite ends of which are immersed into a conductive liquid (41) in a vessel (39) at the other end of the cable. The conductor wire of the picked up core is electrically separated from the other cores and power is supplied to the picked up conductor wire so that a current flows through the picked up wire, the conductive liquid, the conductor wires of other cores and through the contact grip to ground.

Abstract: A shielded cable-connector assembly for interface use comprises a multicore cable (1), a connector (2) and a shielding member made of a metallic mesh (5). The respective cores (11) of the multicore cable are connected to resepective contact elements (21) of the connector and the metallic mesh is disposed to cover the connecting portion of the cores and the contact elements while the same is electrically connected to a metallic contact cover (22) of the connector and a shielding member (12) of the multicore cable, whereby a shielding effect at the connecting portion of the cores and the contact elements is enhanced. A connector cover (24) is provided to cover the whole metallic mesh.