Abstract: The invention provides olefin polymerization catalyst exhibiting excellent polymerization activities, a process for olefin polymerization using the catalyst, a novel transition metal compound useful for the catalyst, and an &agr;-olefin/conjugated diene copolymer having specific properties. The olefin polymerization catalyst of the invention comprises (A) a transition metal compound of formula (I) or (II), and (B) an organometallic compound, an oranoaluminum oxy-compound or an ionizing ionic compound. The novel transition metal compound of the invention is a compound of formula (I) wherein M is a transition meal atom of Group 3 or 4 of the periodic table; m is an integer of 1 to 3; R1 is a hydrocarbon group, etc.; R2 to R5 are each H, a halogen, a hydrocarbon group, etc.; R6 is a halogen, a hydrocarbon group, etc.; n is a number satisfying a valence of M; and X is a halogen, a hydrocarbon group, etc.

Abstract: A process for preparing hydroperoxides which comprises oxidizing hydrocarbon by a gas containing oxygen in the presence of a specific compound and converting them selectively to corresponding hydroperoxides. The specific compound is the compound that can capture radicals. The preferable example may be a compound selected from radicals of oxygen, nitrogen, phosphorus, sulfur, carbon or silicon or a compound that forms radicals of these in the reaction system. The present invention can be applied to oxidation of hydrocarbons including arylalkylhydrocarbons such as cumene, m-diisopropylbenzene, p-diisopropylbenzene, 1,3,5-triisopropylbenzene, isopropylnaphthalene, diisopropylnaphthalene, isopropylbiphenyl, diisopropylbiphenyl, etc.

Abstract: A method for producing aryl alkyl hydroperoxides which comprises selectively oxidizing an aryl alkyl hydrocarbon having the formula: ##STR1## wherein P and Q are hydrogen or an alkyl and may be the same or different from each other; x is an integer of 1-3; and Ar is an aromatic hydrocarbon group having a valence of x, with an oxygen-containing gas in the presence of a transition metal complex which contains, as a ligand, a cyclic polyfunctional amine compound having at least three nitrogen atoms in the ring forming molecular chain or an open chain polyfunctional amine compound having at least three nitrogen atoms in the main chain of the molecule.

Abstract: Disclosed is a polycyclic compound represented by the following formula (I):R.sup.1 --X.sup.1 --[A.sup.1 --X.sup.2 ]--[A.sup.2 --X.sup.3 ]--R.sup.2 (I)wherein R.sup.1 is a (halogenated) alkyl group of 6 to 16 carbon atoms, X.sup.1 is --O-- group or a single bond, A.sup.1 is a biphenylene group, a phenylene group or the like, A.sup.2 is 1-fluoro-3,4-dihydronaphthalene or the like, X.sup.2 and X.sup.3 are each --COO--, a single bond or the like, and R.sup.2 is an optically active group of 4 to 20 carbon atoms which has at least one asymmetric carbon atom. Also disclosed are a liquid crystal material consisting of the polycyclic compound, a liquid crystal composition comprising the liquid crystal material, and a liquid crystal element. This novel polycyclic compound is optically active and capable of being in a smectic phase in a wide temperature range including room temperature. The polycyclic compound can be used as a ferroelectric liquid crystal material or an antiferroelectric liquid crystal material.

Abstract: A method for producing aryl alkyl hydroperoxides which comprises selectively oxidizing an aryl alkyl hydrocarbon having the formula: ##STR1## wherein P and Q are hydrogen or an alkyl and may be the same or different from each other; x is an integer of 1-3; and Ar is an aromatic hydrocarbon group having a valence of x, with an oxygen-containing gas in the presence of a transition metal complex which contains, as a ligand, a cyclic polyfunctional amine compound having at least three nitrogen atoms in the ring forming molecular chain or an open chain polyfunctional amine compound having at least three nitrogen atoms in the main chain of the molecule.

Abstract: A method for producing aryl alkyl hydroperoxides which comprises selectively oxidizing an aryl alkyl hydrocarbon having the formula: ##STR1## wherein P and Q are hydrogen or an alkyl and may be the same or different from each other; x is an integer of 1-3; and Ar is an aromatic hydrocarbon group having a valence of x, with an oxygen-containing gas in the presence of a transition metal complex which contains, as a ligand, a cyclic polyfunctional amine compound having at least three nitrogen atoms in the ring forming molecular chain or an open chain polyfunctional amine compound having at least three nitrogen atoms in the main chain of the molecule.

Abstract: In a photo-mask blank comprising a transparent substrate member and a shading layer of chromium covered on a principal surface of the substrate member, the shading layer has a first portion adjacent the principal surface and etched at a first etch rate and a second portion farther from the principal surface than the first portion and etched at a second etch rate lower than the first etch rate. For this purpose, nitrogen is dispersed so that the first portion becomes rich in nitrogen as compared with the second portion. Alternatively, carbon is dispersed so that the first portion becomes scarce in carbon relative to the second portion. The first portion may include nitrogen. The substrate member may comprise a transparent flat plate and a transparent conductive layer coated on the flat plate. The photo-mask blank is processed into a photo-mask through an etching process.

Abstract: In a photo-mask blank, a transparent substrate is covered with a shading layer including chromium and chromium carbide. Covered on the shading layer, is an antireflection layer which includes chromium and chromium nitride. The shading and the antireflection layers are deposited in the same hollow space by sputtering. An etch rate of the shading layer is adjustable to that of the antireflection layer to make both etch rates equal and, thereby, to reduce undercuts appearing at the shading layer.

Abstract: In a photo-mask blank comprising a transparent substrate member and a shading layer of chromium covered on a principal surface of the substrate member, the shading layer has a first portion adjacent the principal surface and etched at a first etch rate and a second portion farther from the principal surface than the first portion and etched at a second etch rate lower than the first etch rate. For this purpose, nitrogen is dispersed so that the first portion becomes rich in nitrogen as compared with the second portion. Alternatively, carbon is dispersed so that the first portion becomes scarce in carbon relative to the second portion. The first portion may include nitrogen. The substrate member may comprise a transparent flat plate and a transparent conductive layer coated on the flat plate. The photo-mask blank is processed into a photo-mask through an etching process.

Abstract: In a photo-mask blank, a transparent substrate is covered with a shading layer including chromium and chromium carbide. On the shading layer is an antireflection layer which includes chromium and chromium nitride. The shading and the antireflection layers are deposited in the same hollow space by sputtering. The etch rate of the shading layer is adjustable to that of the antireflection layer to make both etch rates equal and, thereby, to reduce undercuts appearing at the shading layer.