Abstract: A polyimide optical waveguide comprising a core made of polyimide whose refractive index is controlled to a predetermined value by electron beam irradiation, and a cladding set in contact with the core and having a refractive index lower than that of the core.

Abstract: A numerical controller for a grinding machine, wherein one of plural reference sizing points is selected according to the contents of a numerical control program. Measured analog data indicating the diameter of a workpiece is received continuously to determine if the size of the machined workpiece coincides with the selected reference sizing point. Upon the coincidence of the size of the machined workpiece with the reference sizing point, a sizing signal is provided, and then machining control is changed in response to the sizing signal. An analog signal provided by a measuring device is sampled at a predetermined interval in a predetermined time. The analog signal is tested to see if the analog signal is in a predetermined range, which is decided based upon the temperature variation or vibrations of the grinding machine. And the result of the test is displayed to facilitate checking the output characteristics of the measuring device.

Abstract: A polyimide optical material, composed of a perfluorinated polyimide having a perfluorinated repeating unit represented by general formula (1) ##STR1## wherein R.sub.1 is a tetravalent perfluorinated organic group; and R.sub.2 is a divalent perfluorinated organic group.

Abstract: A perfluorinated polyimide comprising a repeating unit represented by general formula (1): ##STR1## and a perfluorinated poly(amic acid) comprising a repeating unit represented by general formula (6): ##STR2## wherein R.sub.1 is a tetravalent organic group; and R.sub.2 is a divalent organic group, provided that chemical bonds between carbon atoms and monovalent elements contained in R.sub.1 and R.sub.2 are exclusively carbon-to-fluorine bonds; methods for preparing them; and optical material including the perfluorinated polyimide. 1,4-Bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene dianhydride, 1,4-difluoropyromellitic anhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene, 1,4-difluoropyromellitic acid, and 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrafluorobenzene as well as methods preparing them. The perfluorinated polyimide has a thermal stability and has a low optical loss in an optical communication wavelength region (0.8 to 1.7 .mu.m).

Abstract: An optical waveguide which has properties including low optical losses, facile fabrication, controllable core-cladding refractive index ratio, and a high heat resistance is provided. The optical waveguide for light transmission therethrough has a core made of a polyimide obtained from at least one tetracarboxylic acid dianhydride and at least one diamine. The polyimide is (a) a polyimide homopolymer derived from a diamine represented by formula [I] as follows: ##STR1## (b) a polyimide copolymer derived from at least one diamine including the diamine represented by the formula [I]; or (c) a mixture of the polyimide homopolymers.

Abstract: A bowling lane is disclosed, which comprises a substrate having provided thereon an epoxy resin layer and a polyurethane resin layer in this order. Also disclosed is a method of repairing a bowling lane, comprising coating a degased epoxy resin on the surface of a substrate of a bowling lane to form an epoxy resin layer and further coating a degased polyurethane resin on the epoxy resin layer.

Abstract: A hot-dip aluminium coated steel sheet having excellent corrosion resistance and heat resistance, comprising a steel substrate containing 3 to 18% chromium, not more than 0.02% carbon, 0.1 to 1.5% manganese, 0.005 to 0.08% aluminium, not more than 0.1% silicon, with the balance being iron and unavoidable impurities, and aluminium coating on said sheet substrate. The coated sheet may further comprises a coating layer of nickel or nickel-iron alloy (Ni: 1 to 99%) beneath the aluminium coating, or an Al-Fe-Si-Ni-Cr alloy coating layer of 1 to 10.mu. in thickness and containing 0.05 to 5% nickel, 0.2 to 10% chromium, beneath the aluminium coating.

Abstract: A chromate surface treated steel sheet having very excellent paintability, corrosion resistance, and workability, more specifically surface treated steel sheets for paint coating, having very excellent properties, specifically with respect to corrosion resistance after paint coating, paint adhesion in services long after the paint coating (so-called secondary paint adhesion), corrosion resistance of paint coating defect portions, and resistance to secondary work cracking. The steel sheet contains not more than 0.15% carbon, 0.005 to 0.10% acid soluble aluminium, 0.5 to 20% chromium with the balance being iron and unavoidable impurities, and the chromate coating applied on the steel substrate comprises a metallic chromium layer in an amount ranging from 1 to 300 mg/m.sup.2, and a hydrated chromium oxide layer in an amount ranging from 5 to 50 mg/m.sup.2 in term of the metallic chromium contained therein.

Abstract: A coated optical fiber comprising an optical fiber; a first layer of a thermoplastic rubber composition which is disposed around the circumference of the optical fiber, has a Young's modulus of 0.1 GPa or less, and is capable of extrusion coating; and a second layer of a thermoplastic resin composition which is disposed around the circumference of the first layer, has a linear expansion coefficient of 1.times.10.sup.-5.degree. C..sup.-1 or less and a Young's modulus of 5 GPa or more, and is capable of extrusion coating. The coated optical fiber has excellent transmission characteristics at low and high temperatures and is inexpensive.

Abstract: Coated steel sheet of high corrosion resistance comprises a sheet of steel containing not more than 0.1% by weight of carbon, 0.005 to 0.08% by weight of soluble aluminum and 0.2 to 20% by weight of chromium, the balance being iron and unavoidable impurities. The steel carries a nickel or nickel alloy layer formed on at least one surface thereof and having a thickness of 0.001 to 1.5 microns and a layer of tin formed on the nickel or nickel alloy layer and having a thickness of at least 0.05 micron. A method of producing it is also disclosed.

Abstract: The contact lenses of the present invention are formed of copolymers with monomers having hydroxyl groups and fluoroalkyl groups as their components. This invention makes it possible to provide contact lenses which are excellent not only in oxygen permeability, wettability and hardness, but also in contamination resistance to protein, lipids, etc., and transparency, etc.

Abstract: A process for producing a vinyl chloride polymer, which comprises dissolving a thermoplastic polyurethane soluble in a vinyl chloride monomer in the vinyl chloride monomer and polymerizing the vinyl chloride monomer in the presence of a radical initiator.

Abstract: An incandescent lamp has a bulb with a built-in filament therein, and an infrared ray reflection film formed on one or both of the outer and inner surfaces of the bulb and containing a non-crystalline metal oxide. The infrared ray reflection film is excellent in transmittance of visible rays and in reflectance of infrared rays and does not cause separation.

Abstract: An apparatus for applying a coating of high-viscosity coating material onto a metal strip at high speed, wherein the apparatus hasa roll having recesses or grooves thereon;a supplying source for forcedly filling the coating material in the recesses or grooves provided on the roll;a doctor for removing excessive coating material remaining on the roll having recesses or grooves other than the coating material filled in the recesses or grooves;a coating roll which rotates in contact with the roll having recesses or grooves;at least one smoothing roll of smaller diameter which rotates in contact with the coating roll; anda back-up roll which holds the metal strip against the coating roll.