Abstract: 18.4 grams of 4,4'-(hexafluoroisopropyridine)diphthalic acid dianhydride and 7.5 grams of 1,4-phenylenediamine dihydrochloride are mixed in a solvent consisting of 80 ml of N-methyl-2-pyrrolidone and 20 ml of dichlorobenzene and are heated at an argon atmosphere to raise its temperature from a room temperature to 170.degree. C. slowly and to be reacted for five hours while an azeotropic dihydration of water which is generated at 170.degree. C. is conducted. After the reaction is completed, a reaction product is precipitated in methanol, the precipitate is washed with methanol and dried at 80.degree. C. FIG. 1 shows the infrared spectra of the reaction product.

Abstract: A fluorine-containing polyimide gas separation membrane which is pinhole-free, uniform over a large area, and has a high permeability and a high separation factor .alpha. is provided. A polyimide resin is dissolved in at least one solvent selected from the group consisting of an organic solvent (A) or (B). The organic solvent (A) has a dielectric constant of 30 or less and a dipole moment of 3.0 D or less. The organic solvent (B) mainly contains an organic solvent having at least one ether bonding in the molecular unit. In the next step, the polyimide resin is dipped in a solvent (C) in order for desolvation. The solvent (C) does not dissolve the fluorine-containing polyimide resin while it is miscible with the organic solvent (A) or (B). As a result, an asymmetric gas separation membrane is formed. The fluorine-containing polyimide resin layer comprises a skin layer the thickness L.sub.1 thereof is about 40 nm and a sponge like layer the thickness L.sub.2 thereof is about 30 .mu.m.

Abstract: A laminated asymmetric membrane comprising first and second asymmetric membranes having different molecular structures, in which the first and second asymmetric membranes are laminated. Consequently, the laminated asymmetric membrane having the excellent property of the separation and permeability can be provided at a low cost. The laminated asymmetric membranes of the present invention is manufactured by the following steps: a film-forming dope (1) was prepared by synthesizing fluorine-containing polyimide having a repeating unit expressed by the following Chemical Formula by using diethylene glycol dimethyl ether as a solvent; a film-forming dope (2) was prepared by dissolving polysulfone in diethylene glycol dimethyl ether; the dope (2) from the resulted two dopes was cast on a polyester nonwoven cloth to a thickness of approximately 50 .mu.m by means of an applicator; the dope (1) was lap coated thereon to a thickness of 30 .mu.

Abstract: A homogeneous membrane or an asymmetric membrane which is made of polyimide resin containing fluorine as a main component and has high separation and permeation properties, is used in a method of separating unsaturated hydrocarbon from a mixture of unsaturated and saturated hydrocarbon. The method includes the steps of contacting the mixture onto the membrane made of the polyimide resin having a repeating unit shown in the following formula as a main component, selectively permeating unsaturated hydrocarbon through the membrane, and separating unsaturated hydrocarbon from the mixture. The membrane satisfies the condition of a solubility coefficient ratio between unsaturated and saturated hydrocarbon.gtoreq.1.2 at 25.degree. C. and more than 50 Torr when the absorption of hydrocarbon to the polyimide resin is in equilibrium.

Abstract: The invention relates to the treatment of waste water containing a harmful ion such as a heavy metal ion or fluorine ion by the coagulating sedimentation method using an inorganic coagulant such as an iron compound or an aluminum compound. After separating treated water from the sediment (sludge) in which the harmful ion is incorporated in insoluble form, the pH of a mixture of the sediment and water is suitably adjusted to cause elution of the harmful ion from the sediment. Then the sediment is separated from the eluate and reused as an inorganic coagulant. By reusing the sediment in this manner, the waste water treatment is accomplished without producing a large quantity of sludge and the consumption of inorganic coagulant and auxiliary chemicals can be greatly reduced, while the concentration of the harmful ion in the treated water becomes sufficiently low.

Abstract: The present invention provides a disk for recording specified data having a plurality of helically formed track areas with one round of the circumferential direction of the disk as one track and a plurality of sector areas in which the plurality of track areas given track numbers added continuously from the outer peripheral direction of the disk are dividedly formed. The plurality of sector areas further include a plurality of data areas for storing the specified data and one parity sector for storing the parity of the specified data stored therein. The plurality of sector areas are given sector numbers added continuously from the starting positions of the track areas. In an information recording block having the plurality of sector areas included in the specified number of ones of the plurality of track areas, a plurality of parities recorded in the parity sector areas of these track areas are calculated by using different track and sector numbers.

Abstract: A method of separating a gas, especially carbon dioxide, from a gas mixture of the gas and nitrogen at a low temperature of -20.degree. C. to 50.degree. C. using a gas separation membrane permeable to the gas, including the step of cooling the gas mixture using at least one cooling medium selected from the group consisting of liquefied petroleum gas and liquefied natural gas. The liquefied petroleum gas comprises at least one selected from the group consisting of propane gas and butane gas in an amount of more than 50 vol. %. The gas separation membrane has a CO.sub.2 permeation rate of 1.times.10.sup.-4 to 5.times.10.sup.-2 N cm.sup.3 /(cm.sup.2 cm Hg sec) at 25.degree. C. and a CO.sub.2 /N.sub.2 separation factor of 10 to 200 at 25.degree. C.

Abstract: A composite reverse osmosis membrane comprising a thin film and a microporous substrate as a support therefor, said thin film mainly comprising a crosslinked polyamide obtained by the interfacial polymerization of(a) an amine component comprising at least one monomeric amine compound having at least two primary or/and secondary amino groups and(b) an acid halide component which is either a benzenehexacarbonyl halide or a mixture of a benzenehexacarbonyl halide with a monomeric acid halide compound having at least two acid halide groups. The composite reverse osmosis membrane exhibits high water permeability and high desalting performance even when used at a low operation pressure of, e.g., 5 kgf/cm.sup.2.

Abstract: A gas separating composite membrane comprising two types of polyimide resin layers having different molecular structures and each having solubility in an organic solvent different from each other, the two layers being laminated being substantially independent or via a mixed layer, the first polyimide resin layer comprising a porous polyimide supporting membrane having a nitrogen gas permeation flux density at 25.degree. C. of at least 2 Nm.sup.3 /m.sup.2 /h/atm., and the second polyimide resin layer, which contributes to a gas separating performance comprising a fluorine-containing polyimide thin film containing at least three fluorine atoms in a repeating molecular structure unit which constructs the second polyimide resin layer has a very high gas permeation flux density while maintaining a high gas permeability, excels in heat resistance and chemical resistance, and satisfies a practical use in terms of cost.

Abstract: As isothiazole derivative represented by the formula (I), ##STR1## wherein R.sup.1, R.sup.2, Y and Z have the same meanings as defined in the description of the specification, and it is useful as an active ingredient for fungicidal and/or bactericidal compositions for use in industry, agriculture and medical treatment.

Abstract: A method of producing a high permeable composite reverse osmosis membrane which comprises forming a polyamide type skin layer on a porous support by the process comprising a step of coating a solution A containing a compound having at least two reactive amino groups on the porous support and a step of contacting a solution B containing a polyfunctional acid halide with the coated layer of the solution A, wherein the difference between a solubility parameter of the solution A and a solubility parameter of the solution B is from 7 to 15 (cal/cm.sup.3).sup.1/2.

Abstract: There are provided a deproteinized natural rubber latex which comprises a purified product of proteolytically treated natural rubber latex and contains fine particles of natural rubber latex, a deproteinized natural rubber which comprises a dehydrated product of the deproteinized natural rubber latex, and a process for the production of deproteinized natural rubber latex which comprises subjecting a latex solution prepared by (1) adding water and/or a surfactant to a natural rubber latex and then proteolytically treating the resulting latex solution or (2) proteolytically treating a natural rubber latex and then adding water and/or a surfactant to the treated natural rubber latex, to purification using a rotary plate membrane separation apparatus.

Abstract: An isothiazole derivative represented by the general formula (I): ##STR1## (wherein R and R.sup.1 are as defined in the general description, and n is an integer of 1 or 2), a process for producing the same, and the usage thereof.

Abstract: A composite reverse osmosis membrane composed of a microporous support layer and a thin layer supported thereon, characterized in that the thin layer is made of a crosslinked polyamide which comprises a polyamine component having two or more amino groups in the molecule and an acid component containing a linear aliphatic polyacid halide having two or more halogenated carbonyl groups in the molecule.

Abstract: The invention is concerned with a process of separation and refining of rare earths in which a dilute solution of rare earths, resulting from the step of separating and refining the rare earths by using an ion exchanger, is subjected to reverse osmosis membrane separation treatment to concentrate the solution and reduce its volume, while the water which has passed through the membrane is circulated for reuse in the step of separating and refining the rare earths.

Abstract: A concrete filled steel tube column. The concrete filled steel tube column includes a steel tube having an inner face; a concrete core disposed within the steel tube; and a separating layer interposed between the inner face of the steel tube and the concrete core for separating the concrete core from the inner face of the steel tube so that the steel tube may not be bonded to the concrete core. After the separating layer is formed on the inner face of the steel tube, the concrete is charged into the steel tube to form a concrete core.

Abstract: A .DELTA..sup.2 -1,2,4-triazolin-5-one derivative represented by the following general formula (I), a process for manufacturing thereof, a herbicidal composition comprising it as an active ingredient, and a use of it as a herbicide: ##STR1## wherein R is a hydrogen atom, a univalent alkali metal atom, an unsubstituted quaternary ammonium salt, a substituted quaternary ammonium salt having at least one C.sub.1 -C.sub.4 alkyl group as a substituent, an unsubstituted-alkyl group having 1 to 6 carbon atoms, a C.sub.1 -C.sub.6 substituted-alkyl group having at least one halogen atom as a substituent, a cycloalkyl group having 3 to 6 carbon atoms, a C.sub.1 -C.sub.

Abstract: A sulfonated polysulfone composite semipermeable membrane comprising a support membrane having laminated thereon in unity a semipermeable membrane composed of a sulfonated polysulfone formed by sulfonating a polysulfone composed of a recurring unit shown by formula (A) ##STR1## wherein n is an integer of 1 or more and process for producing the same.

Abstract: A selective shading device has a number of shading plates or planar members and a supporting body that holds the plates or planar members in such a manner that they are arrranged radially with respect to an optical axis. The device blocks sagittal bundles of rays. A preferred example of the supporting body is a cylindrical frame that holds the shading plates perpendicularly to the inner surface thereof. Alternatively, the shading planar members are formed within a lens element along the edge thereof.

Abstract: A novel ketene S,S-acetal derivative which is useful as an antimycotic agent and an agricultural chemical of fungicidal, plant growth regulating or insecticidal properties represented by the general formula (I): ##STR1## wherein R represents a hydrogen atom; an alkyl group having 1 to 8 carbon atoms; a cycloalkyl group having 3 to 6 carbon atoms; a methylene group; a lower alkenyl group; a lower alkyl group substituted by a halogen atom, a cyano group, a lower alkoxyl group, a lower alkylthio group; a carbamoyl group, an acyl group, or an alkenoyloxy group; a phenyl group represented by ##STR2## (in which R.sub.