Abstract: A transition metal compound having a ligand with an azaferrocene structure or a ferrocene structure. The transition metal compound is used in combination with an activating cocatalyst, as a catalyst for polymerization of olefins.

Abstract: A transition metal compound having a ligand with an azaferrocene structure or a ferrocene structure. The transition metal compound is used in combination with an activating cocatalyst, as a catalyst for polymerization of olefins.

Abstract: A magnetic recording apparatus has a rotating drum which rotates magnetic heads at a constant speed. The magnetic heads scan a magnetic tape. On a magnetic tape, an area written by each scan always includes a lateral portion of an area written by the previous scan. In this portion, old data is overwritten by new data, and writing continues. An area excluding the overwritten portion is a recording track. The running speed of the magnetic tape is changed by a system controller, and hence the recording track width can be changed.

Abstract: A transition metal compound having a ligand with an azaferrocene structure or a ferrocene structure. The transition metal compound is used in combination with an activating cocatalyst, as a catalyst for polymerization of olefins.

Abstract: A magnetic recording apparatus has a rotating drum which rotates magnetic heads at a constant speed. The magnetic heads scan a magnetic tape. On a magnetic tape, an area written by each scan always includes a lateral portion of an area written by the previous scan. In this portion, old data is overwritten by new data, and writing continues. An area excluding the overwritten portion is a recording track. The running speed of the magnetic tape is changed by a system controller, and hence the recording track width can be changed.

Abstract: A polyolefin of a high molecular weight is produced by using a catalyst comprising a transition metal compound represented by General Formula (1):

Abstract: A novel catalyst for polymerization of olefin is provided which comprises a modified clay compound (a) having an average particle diameter of less than 10 .mu.m, a transition metal compound (b), and an organoaluminum compound (c). This catalyst exhibits improved initial polymerization behavior, and produces an olefin polymer of less ash content at a high productivity.

Abstract: A catalyst for polymerization of an olefin, which comprises (a) a transition metal compound of the following formula (1), (2) and/or (3): ##STR1## wherein each of M.sup.1, M.sup.2 and M.sup.3 is a titanium atom, a zirconium atom or a hafnium atom, each of Cp.sup.1, Cp.sup.2, Cp.sup.3, Cp.sup.4 and Cp.sup.5 is a cyclopentadienyl group, an indenyl group, a fluorenyl group or a substitution product thereof, R.sup.1 is a hydrogen atom, a C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilyl group, each of X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5 and X.sup.6 is a hydrogen atom or a C.sub.1-20 hydrocarbon group, Z.sup.1 is a C.sub.1-20 hydrocarbon group, a silicon-containing C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilanediyl group, which serves to connect Cp.sup.3 and Cp.sup.4, Z.sup.2 is a C.sub.1-20 hydrocarbon group, a silicon-containing C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilanediyl group, which serves to connect Cp.sup.

Abstract: Analyst for polymerization of olefin is provided which comprises a clay mineral (a) having been modified with a compound (b) capable of introducing a cation into layer interspaces in the clay mineral; a metallocene compound (c); and an organoaluminum compound (d). This catalyst is inexpensive and yet has excellent activity for polymerization of olefin. The process for polymerization or copolymerization of olefins is also provided.

Abstract: A catalyst for olefin polymerization obtainable by contacting:(a) a transition metal compound containing a transition metal of the Group 4 of the Periodic Table,(b) an organometallic compound, and(c) a solid catalyst component comprising a carrier and an ionized ionic compound capable of forming a stable anion on reaction with a transition metal compound, wherein the ionized ionic compound comprises a cationic component and an anionic component and the cationic component is fixed on the surface of the carrier. The catalyst system of the invention enables production of olefin polymers with excellent physical properties at good productivity without causing contamination of a polymerization vessel.

Abstract: A novel organic transition metal compound is disclosed, which is represented by the following formula (1): ##STR1## wherein the all symbols are defined in the disclosure. A polymerization catalyst comprising the organic transition metal compound and a process for the preparation of a polyolefin using the polymerization catalyst are also disclosed.

Abstract: A novel class of olefin polymerization catalyst system based on specific organo-transition metal compounds and which are effective for controlling in particular the width and mode of the molecular weight distribution of the resulting polyolefins, and processes of olefin polymerization using the novel catalyst systems are disclosed.

Abstract: A method for producing a stereospecific polyolefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises (A) a solid catalyst component prepared by reacting a homogeneous solution containing (i) at least one member selected from the group consisting of metal magnesium and a hydroxylated organic compound, and oxygen-containing organic compounds of magnesium, (ii) an oxygen-containing organic compound of aluminum and (iii) an oxygen-containing organic compound of titanium, with (iv) at least one aluminum halide compound to obtain a solid product, and further reacting to this solid product, (v) an electron-donative compound and (vi) a titanium halide compound, (B) at least one member selected from the group consisting of organometallic compounds of Groups IA, IIA, IIB, IIIB and IVB of the Periodic Table, and (C) an oxygen-containing organic compound of silicon which has no aromatic substituent and which has at least

Abstract: A fast reactor comprises a core composed of nuclear fuel, a core barrel surrounding an outer periphery of the core, an annular reflector surrounding an outer periphery of the core barrel, a partition wall structure surrounding an outer periphery of the annular reflector and supporting the core barrel by a supporting structure arranged radially of the fast reactor, the partition wall structure constituting an inner wall of a coolant passage for a primary coolant, a neutron shield surrounding an outer periphery of the partition wall structure and disposed in the coolant passage, a reactor vessel surrounding an outer periphery of the neutron shield and having an inner wall constituting an outer wall of the coolant passage, and a guard vessel surrounding an outer periphery of the reactor vessel.

Abstract: A method for producing a stereospecific polyolefin in the presence of a catalyst comprising a transition metal compound and an organometallic compound, wherein a catalyst system is used which comprises: (A) a solid catalyst component prepared by reacting (i) a homogeneous solution prepared by reacting (i-1) magnesium and a hydroxylated organic compound, (i-2) an oxygen-containing organic compound of titanium and/or (i-3) an oxygen-containing organic compound of silicon, with an oxygen-containing organic compound of aluminum and/or a boron compound, with (ii) at least one aluminum halide compound to obtain a solid product, reacting to this solid product (iii) an electron-donative compound and (iv) a titanium halide compound to obtain a solid component, and further reacting to this solid component (v) silicon tetrachloride and/or an alkyl-substituted product of silicon tetrachloride, (B) at least one member selected from the group consisting of organometallic compounds of Groups IA, IIA, IIB, IIIB and IVB of th

Abstract: A method of producing a polyolefin, which comprises polymerizing at least one olefin in the presence of a catalyst system comprising(A) a catalyst component prepared by bringing ethylene and/or an .alpha.-olefin in contact with a solid composite obtained by reacting a reaction product, which has been produced by reacting a uniform solution containing(i) at least one member selected from the group consisting of metal magnesium and hydroxylated organic compound, and oxygen-containing organic compounds of magnesium and(ii) at least one oxygen-containing organic compound of titanium with(iii) at least one organoaluminum compound and/or(iv) at least one silicon compound, with(v) at least one aluminum halide compound, thereby allowing the ethylene and/or the .alpha.-olefin to be absorbed into the solid composite, and(B) at least one catalyst component selected from the group consisting of organometallic compounds of metals of Groups Ia, IIa, IIb, IIIb and IVb of the Periodic Table.

Abstract: A process for producing a polyolefin, which comprises polymerizing at least one olefin in the presence of a catalyst system comprising (A) a solid catalyst component (A) obtained by reacting to a uniform solution containing (i) at least one member selected from the group consisting of metallic magnesium and an organic hydroxide compound, and an oxygen-containing organic magnesium compound, and (ii) at least one oxygen containing organic titanium compound, (iii) at least one organic aluminum compound, (iv) at least one boron compound having an alkoxy group, and (v) at least one aluminum halide compound; and (B) at least one catalyst component (B) selected from the group consisting of organic metal compounds of metals of Groups Ia, IIa, IIb, IIIb and IVb of the Periodic Table.

Abstract: Ethylene is polymerized, optionally with a small amount of an .alpha.-olefin, in the presence of a Ziegler catalyst in multiple stages by using a polymerization apparatus including at least three polymerization reactors. In the polymerization process, the following three ethylene polymer components U, H and L are prepared sequentially in an optional order; a component U having an .alpha.-olefin content .alpha..sub.U of 0.1-10 wt. % and an intrinsic viscosity [.eta.].sub.U satisfying 2.times.[.eta.].sub.W .ltoreq.[.eta.].sub.U .ltoreq.5.times.[.eta.].sub.W in which [.eta.].sub.W is the intrinsic viscosity of the entire ethylene polymer, the ratio R.sub.U of component U in the entire ethylene polymer satisfying 0.3.times.[.eta.].sub.W .ltoreq.[.eta.].sub.U .times.R.sub.U .ltoreq.0.8.times.[.eta.].sub.W ; a component H having an .alpha.-olefin content .alpha..sub.H of up to 20 wt. % and an intrinsic viscosity [.eta.].sub.H satisfying ([.eta.].sub.W).sup.1/2 .ltoreq.[.eta.].sub.H .ltoreq.1.5.times. [.eta.].sub.

Abstract: A manufacturing method of polyolefin characterized in that at least one kind of olefins is allowed to polymerize in the presence of a catalyst system comprising(A) solid catalyst ingredient (A) obtained through the successive reaction steps, wherein, with a homogeneous solution involving(i) at least one member selected from metallic magnesium and hydroxylated organic compounds and oxygen-containing organic compounds of magnesium, and(ii) at least one kind of oxygen-containing organic compounds of titanium, are allowed to react in sequence with:(iii) at least one kind of organoaluminum compounds, then(iv) at least one kind of silicon compounds and further(V) at least one kind of halogenated aluminum compounds and(B) at least one kind of catalyst ingredients (B) selected from organometallic compounds, the metal of which belongs to Ia, IIa, IIb, IIIb or IVb group in the periodic table.

Abstract: A nuclear reactor of the type which uses liquid metal as primary and secondary coolants, and wherein the reactor vessel contains a core and a plurality of vertically extending cylindrical intermediate heat exchangers for carrying out heat exchange between the primary and secondary coolants; primary coolant circulation pumps disposed outside of the reactor vessel; a pipe for conducting to the circulation pump the primary coolant which has passed through the intermediate heat exchangers after leaving the core; and a pipe for guiding the primary coolant discharged from the circulation pump to the core through the reactor vessel.