Abstract: A method of replacing a first dispersion medium, in a starting slurry composed of the first dispersion medium and either terephthalic acid crystals or isophthalic acid crystals, with a second dispersion medium, and apparatus therefore. The starting slurry is tangentially fed to a vertically extending cylindrical portion of a cyclone-shaped nozzle disposed at an upper portion of a replacement tank of a dispersion medium replacement apparatus, from a tangential direction of the cylindrical portion, and moves circularly along an inner wall of the cylindrical portion. The slurry circularly moving is then discharged from an opening which is disposed at a vertically lower end of the cylindrical portion and dispersed in a second dispersion medium which is fed from a lower portion of the replacement tank.

Abstract: A composition containing 3,3?-thiobis(propane-1,2-dithiol) and one or more enic compounds which composition is photocurable and can give a cured product having a high refractive index and adequate hardness.

Abstract: In the process of the present invention, a recovered polyamide is used as a part of the raw materials for producing polyamide. By carrying out the polycondensation under a condition such that the recovered polyamide is dissolved in the reaction system during the polycondensation, the properties of the polyamide being produced are not deteriorated as compared with those of polyamide which is produced without using the recovered polyamide. By changing the addition amount of the recovered polyamide, the crystallization speed of the resultant polyamide is controlled or increased as compared when produced without using the recovered polyamide.

Abstract: A method of producing polycarbonate resin pellets containing very less residual organic solvent and low molecular weight volatile matters and having a high transparency by melt-kneading a polycarbonate resin powder in an extruder equipped with a screw having a material seal mechanism, and vents, and devolatilizing the residual organic solvent and/or the low molecular weight volatile matters at the vent portion and then extruding the molten resin.The polycarbonate resin pellets are suitable for optical grade articles and automobile lenses.

Abstract: A substrate for a laminate which comprises a nonwoven fabric which is composed mainly of a liquid crystal polyester fiber, and which is subjected to (1) an entangling treatment, (2) a heating treatment to impart adhesivity to a thermosetting resin, and (3) a surface-modifying treatment, and a laminate containing at least one prepreg prepared by impregnating the substrate with a thermosetting resin and drying are disclosed. The substrate of the present invention has low dielectric constant, is light, exhibits low hygroscopicity, and has good properties to be impregnated with the thermosetting resin and good adhesiveness to the thermosetting resin.

Abstract: A reflection type magnetooptic sensor head. The respective structural elements are aligned in the order of a light source, light inputting/outputting path, polarizer, Faraday rotator, and reflecting film. The Faraday rotator is made of a (111) bismuth-substituted iron garnet single crystal film. The Faraday rotator is positioned such that the optical axis of the light incident upon the surface of the Faraday rotator makes an angle of 10 to 70 degrees with an axis normal to the surface of the Faraday rotator. The sensor head may further include two identical rectangular prisms positioned such that the Faraday rotator is sandwiched between the slanting surfaces of the prisms.

Abstract: This invention relates to use of compounds of the formula ##STR1## wherein R represents a C.sub.2-5 alkyl, C.sub.2-5 alkenyl or C.sub.2-5 alkynyl group, and X represents a hydrogen atom, a C.sub.2-8 alkylcarbonyl, carbamoyl, benzoyl, chloromethylcarbonyl or methoxycarbonyl group, or --PO.sub.3 H.sub.2, and Y represents a chlorine or bromine atom in promoting the growth of plants.

Abstract: A glass-reinforced polycarbonate resin composition comprising an aromatic polycarbonate resin (a) and, blended therewith, 5 to 60% by weight based on the weight of the composition of a glass reinforcement (b) which has been treated with an acid.The composition has excellent dimensional stability, mechanical strength, heat resistance and electrical characteristics, and is therefore used in industrial fields of cameras, VTR's, facsimiles and the like.

Abstract: An improved process for producing aromatic polyethers by condensation polymerizing aromatic dihydroxy compounds represented by the general formula: HO--Ar--OH and aromatic dichloro compounds represented by the general formula: Cl--Ar.sup.1 --Y--Ar.sup.2 --Cl, or condensation polymerizing monohydroxymonochloro aromatic compounds represented by the general formula: HO--Ar.sup.1 --Y--Ar.sup.2 --Cl (in the above formulae, Ar, Ar.sup.1, Ar.sup.2 are as defined in the specification) in the presence of alkali metal compounds comprising a combination of alkali metal carbonates comprising carbonate and/or hydrogencarbonate of an alkali metal, e.g., potassium, and alkali metal fluorides.In accordance with the present process, high molecular weight aromatic polyethers can be efficiently produced from aromatic chloro compounds which are inexpensive and easily available.

Abstract: Dimethyl formamide is produced in high yield with high selectivity by reaction of monomethyl formamide with trimethylamine and carbon monoxide in the presence of a catalyst such as halogen elements, halides, inorganic acids, solid acids and metal carbonyls at a temperature of 150.degree. to 300.degree. C under a pressure of 20 kg/cm.sup.2 gage or higher.