Abstract: An apparatus for generating a mixture of oxygen gas and hydrogen gas is provided with an electrolytic cell in which electrolysis of electrolyte therein is performed to generate the mixture of the oxygen and the hydrogen gas by electricity being applied from an electrical conversion device and having a plurality of electrode plates arranged with separation, a insulating materials attached to inner wall surfaces of the electrolytic cell and having at least one surface grooves formed thereon into which the electrode plates are inserted, a water supply device for supplementing the water into the electrolytic cell, the water supply device connected to the electrolytic cell, a gas reservoir for restoring the mixture generated in the electrolytic cell, the gas reservoir connected to the electrolytic cell, and a cooling unit for maintaining temperature inside the electrolytic cell constant connected to the electrolytic cell.

Abstract: The present invention relates to a process of preparing polycarbonate, more specifically to a process of preparing polycarbonates by solid state polymerization using microwave radiation, which comprises steps of preparing polycarbonate prepolymer having a certain range of viscosity average molecular weight; converting said polycarbonate prepolymer into crystalline particles having a certain degree of crystallinity; and producing polycarbonates by solid state polymerization of said crystalline particles by applying microwave radiation, thus resulting in production of high quality polycarbonates with high molecular weight within short time.

Abstract: A valve body is provided with a valve chamber with a predetermined size having at both ends a fluid inlet and a fluid outlet, a coil spring mounted within the valve chamber of the valve body and expanding and contracting depending upon a variation of fluid temperature with respect to a predetermined value, and a needle inserted into the coil spring for opening and closing fluid passages by moving leftward and rightward within the valve chamber in response to the expansion and contraction of the coil spring.

Abstract: The present invention relates to polyamide-imides having head-to-tail backbone and more particularly, to polyamide-imimdes having head-to-tail ragularity to provide excellent heat and chemical resistance, physical and mechanical properties, processability, and gas permeability and selectivity.

Abstract: The present invention relates to a process of preparing polycarbonates and more particularly, to the process of preparing polycarbonates through a melt polymerization reaction of dihydroxyaryl compounds with diarylcarbonate, wherein said melt polymerization is performed in the presence of a mixed catalyst composed of an oxygen (O) or sulfur (S) containing compound having lone-pair electrons and an alkali metal or alkaline earth metal salt in an appropriate ratio at a reduced temperature by accelerating a reaction rate to obtain high quality polycarbonates with higher than 15,000 g/mole of a viscosity average molecular weight and improved color.

Abstract: A valve body is provided with a valve chamber with a predetermined size having at both ends a fluid inlet and a fluid outlet, a coil spring mounted within the valve chamber of the valve body and expanding and contracting depending upon a variation of fluid temperature with respect to a predetermined value, and a needle inserted into the coil spring for opening and closing fluid passages by moving leftward and rightward within the valve chamber in response to the expansion and contraction of the coil spring.

Abstract: The present invention relates to a process of preparing polycarbonates, more specifically to a process of preparing polycarbonates by solid state polymerization using microwave radiation, which comprises steps of preparing polycarbonate prepolymer having a certain range of viscosity average molecular weight; converting said polycarbonate prepolymer into crystalline particles having a certain degree of crystallinity; and producing polycarbonates by solid state polymerization of said crystalline particles by applying microwave radiation, thus resulting in production of high quality polycarbonates with high molecular weight within short time.

Abstract: The present invention relates to a process of preparing polycarbonates and more particularly, to the process of preparing polycarbonates through a melt polymerization reaction of dihydroxyaryl compounds with diarylcarbonate, wherein said melt polymerization is performed in the presence of a mixed catalyst composed of an oxygen (O) or sulfur (S) containing compound having lone-pair electrons and an alkali metal or alkaline earth metal salt in an appropriate ratio at a reduced temperature by accelerating a reaction rate to obtain high quality polycarbonates with higher than 15,000 g/mole of a viscosity average molecular weight and improved color.

Abstract: An apparatus for generating a mixture of oxygen gas and hydrogen gas is provided with an electrolytic cell in which electrolysis of electrolyte therein is performed to generate the mixture of the oxygen and the hydrogen gas by electricity being applied from an electrical conversion device and having a plurality of electrode plates arranged with separation, a insulating materials attached to inner wall surfaces of the electrolytic cell and having at least one surface grooves formed thereon into which the electrode plates are inserted, a water supply device for supplementing the water into the electrolytic cell, the water supply device connected to the electrolytic cell, a gas reservoir for restoring the mixture generated in the electrolytic cell, the gas reservoir connected to the electrolytic cell, and a cooling unit for maintaining temperature inside the electrolytic cell constant connected to the electrolytic cell.

Abstract: The present invention relates to a process for the preparation of polycarbonates, more specifically to a process for the preparation of polycarbonates by a solid polymerization of prepolymers obtained by the polymerization between aromatic dihydroxides and diarylcarbonates, which comprises: a) preparing said prepolymer having a viscosity average molecular weight of 4,000-18,000 g/mole; b) preparing a microporous foam by injecting high-pressure inert gas; and c) preparing polycarbonates by a solid polymerization, which facilitates the removal of phenol, a by-product, and enhances molecular weight of polycarbonates without using any catalyst due to the relatively high polymerization rate.

Abstract: The invention herein relates to a process of preparing a novel polyimide foam having superior heat-resistance, flame retardancy, homogeneous size and distribution of cells, and low density, wherein a polyimide precursor in a granular form is prepared by means of using heterocyclic amine as catalyst and then foaming. According to the present invention, the preparing process of a polyimide foam comprises reacting aromatic carboxylic acid or the anhydrides thereof with an excess of aliphatic univalent alcohol to yield an aromatic ester solution. To the aromatic ester solution, divalent amines or the mixture thereof were added in the equivalent amount of said carboxylic acid or the anhydrides thereof in addition to a catalyst and surfactant to yield a polyimide. Then, the precursor in a granular form mixture was imidized while foaming by means of pre-heating and then heating in a microwave oven, after which was cured at a high temperature.

Abstract: A novel Trichosporonoides madida CJ-NT1 microorganism which is capable of converting fermentable sugars to a high titre of erythritol under low aeration conditions and a method of producing erythritol by fermentation of sugar, which comprises culturing the cells of the Trichosporonoides madida CJ-NT1 strain are provided.

Abstract: A novel Trichosporonoides madida CJ-NT1 microorganism which is capable of converting fermentable sugars to a high titre of erythritol under low aeration conditions and a method of producing erythritol by fermentation of sugar, which comprises culturing the cells of the Trichosporonoides madida CJ-NT1 strain are provided.

Abstract: Polyamideimide resins having the formula (I) ##STR1## in which repeating units are bound in a head to tail or head to head manner,R is at least two divalent groups selected from the group consisting of ##STR2## (cis-, trans- conformational mixture) wherein one divalent group is ##STR3## group in a PAI molecule, produced by introducing isophorone diamine into the conventional aromatic polyamideimide resins.