Abstract: Disclosed herein is a thrust fin for ships which recovers lost energy caused by rotational flow generated behind a propeller, and converts it into thrust. The thrust fin of the present invention has a simple shape, enhances propulsive efficiency of the ship, and can be applied to a real ship thanks to the simple installation thereof, to maximize thrust of the ship. The thrust fin is mounted to a front portion of the rudder of the ship such that left and right sides of the thrust fin, which are integrated with each other into a single body, are asymmetrical. A vertical position, at which the thrust fin is mounted to the rudder, is at an optimum position as determined in consideration of the shape of the rudder and hydrodynamic characteristics.

Abstract: A novel polyvinyl alcohol-based polymer membrane is disclosed. The novel polyvinyl alcohol-based polymer membrane of the present invention comprises two different compounds which are crosslinked by irradiating light such as UV or electronic beams or heat treatment to form a covalent bond between double bonds thereby providing improved properties such as chemical resistance and durability. This invention also relates to a process its preparation.

Abstract: The present invention relates to a method for preparing hexafluoropropylene oxide with high yield, and particularly to a method for preparing hexafluoropropylene oxide comprising the step of performing a two-phase interfacial reaction between an organic phase containing hexafluoropropylene and an aqueous phase containing a hypochlorite oxidant in the presence of a phase-transfer catalyst and a non-ionic surfactant to improve the degree of emulsification and dispersion of the organic phase and to increase the contact interfacial area, thereby increasing the efficiency and the yield of the reaction.

Abstract: The present invention relates to a method for preparing hexafluoropropylene oxide with high yield, and particularly to a method for preparing hexafluoropropylene oxide comprising the step of performing a two-phase interfacial reaction between an organic phase containing hexafluoropropylene and an aqueous phase containing a hypochlorite oxidant in the presence of a phase-transfer catalyst and a non-ionic surfactant to improve the degree of emulsification and dispersion of the organic phase and to increase the contact interfacial area, thereby increasing the efficiency and the yield of the reaction.

Abstract: Disclosed herein is a thrust fin (20) for ships which recovers lost energy caused by rotational flow generated behind a propeller (30), and converts it into thrust. The thrust fin (20) of the present invention has a simple shape, enhances propulsive efficiency of the ship, and can be applied to a real ship thanks to the simple installation thereof, to maximize thrust of the ship. The thrust fin (20) is mounted to a front portion of the rudder (10) of the ship such that left and right sides of the thrust fin, which are integrated with each other into a single body, are asymmetrical. A vertical position, at which the thrust fin (20) is mounted to the rudder (10), is at an optimum position as determined in consideration of the shape of the rudder and hydrodynamic characteristics.

Abstract: A novel polyvinyl alcohol-based polymer membrane is disclosed. The novel polyvinyl alcohol-based polymer membrane of the present invention comprises two different compounds which are crosslinked by irradiating light such as UV or electronic beams or heat treatment to form a covalent bond between double bonds thereby providing improved properties such as chemical resistance and durability. This invention also relates to a process its preparation.