摘要:
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.
摘要:
To provide a medical tray which can be made more compact upon discarding, the medical tray has a bottom portion, a side wall provided along an outer periphery of the bottom portion, and a pair of side wall deformation guiding portions provided at opposing positions of the side wall for guiding the side wall when the side wall is deformed into a convex state toward the bottom portion.
摘要:
An oil tempered wire, characterized in that it comprises a wire material and, formed on the surface thereof, a coating film comprising one or more inorganic salts selected from the group consisting of a sulfate, a silicate and a borate. The coating film optionally further comprises fats and oils and/or a soap exhibiting lubricity. The oil tempered wire has a coating film exhibiting satisfactory heat resistance and good lubricity and thus can secure good coiling workability even in the case of a high strength wire or a wire having a heteromorphic section.
摘要:
A perfluorinated aromatic compound represented by general formula (7): ##STR1## wherein R.sub.3 is a tetravalent perfluorinated aromatic group represented by formula (8): ##STR2## wherein (R.sub.4)s are the same, each being a carboxyl group or a cyano group, or two adjacent (R.sub.4)s combine to form a divalent group represented by formula (10): ##STR3## provided that when R.sub.4 is a cyano group, R.sub.3 denotes said tetravalent perfluorinated aromatic group represented by formula (9).
摘要:
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.
摘要翻译:铬酸盐表面处理钢板具有非常优异的可涂饰性,耐腐蚀性和可加工性,更具体地说是用于涂料的表面处理钢板,具有非常优异的性能,特别是涂漆后的耐腐蚀性,涂料后的涂料粘合性 涂层(所谓的二次漆附着),涂料缺陷部分的耐腐蚀性,以及二次加工开裂性。 该钢板含有不超过0.15%的碳,0.005〜0.10%的酸溶性铝,0.5〜20%的铬,余量为铁和不可避免的杂质,施加在钢基材上的铬酸盐镀层含有金属铬层 范围为1〜300mg / m 2,水合氧化铬层的含量为5〜50mg / m 2。
摘要:
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.
摘要:
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.
摘要:
A method for preparing aromatic compounds including 1,4-difluoropyromellitic dianhydride represented by formula (12): ##STR1## and 1,4-difluoropyromellitic acid represented by formula (15): ##STR2## by dehydrating or hydrolyzing and dehydrating precursors.
摘要:
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).
摘要:
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.