Abstract: A method for forming a field oxide film in a semiconductor device comprises the steps of sequentially forming a pad oxide film and a first buffer silicon nitride film on a silicon substrate, and then forming a first patterned mask on the first buffer silicon nitride film. Subsequently, the resulting exposed part of the first buffer silicon nitride film is etched to expose a portion of the pad oxide film. The first patterned mask is them removed. A buffer oxide film is formed on the resulting exposed part of the pad oxide film and the etched first buffer silicon nitride film. Then, a second buffer silicon nitride film and a second patterned mask is sequentially formed on the buffer oxide film, followed by etching of the resulting exposed part of the second buffer silicon nitride. The second patterned mask is then removed, followed by a formation of a field oxide film by thermal oxidation on the resulting structure. The second buffer silicon nitride is then removed.

Abstract: A method for preparation of a polyether-ester elastomer. The method comprises admixturing dibasic acid with short chain diol for the formation of a short chain ester monomer represented :into general formula (I) and with polyglycol for the formation of a long chain ether moromet represented into general formula (II), adding the alkali salt of dialkylsufoisophthalate to the admixture to react the admixture until the discharge of methanol is tip to above 70%, adding stabilizing agent to perform the polymerization reaction, and then, blending phenolic alkali metal salt. ##STR1## wherein R is a biradical obtained by removing carboxyl group from a dicarboxylic acid having a molecular weight not more than 400,D is a biradical obtained by removing hydroxyl group from a short chain diol having a molecular weight not more than 250, andG is a biradical obtained by removing hydroxyl group from a long chain ether glycol having a molecular weight of a range of about 400 to 4,000.

Abstract: A vacuum cleaner which is able to be used for water extraction cleaning and for dry suction cleaning. The cleaner comprises a dry suction cleaning device and a water extraction cleaning device which are movable individually under the connected condition thereof. The water extraction cleaning device includes an air-liquid separation surface such that air and liquid impinge against the air-liquid separation surface, thereby causing entrained liquid droplets to be separated from the incoming air, a second air-liquid separation surface disposed at downstream of the first separation surface such that air and liquid past the first separation surface impinge against the second air-liquid separation surface, thereby causing small droplets to be separated from air. The present vacuum cleaner perfectly prevents water from incoming toward a motor, that is a suction device and effectively cleans smooth flat floors as well as carpet, when used for water extraction cleaning.

Abstract: A cleaner head is disclosed which comprises: a cleaning fluid spraying nozzle formed at the center of the bottom of the cleaner head; a leading suction nozzle and a leading brush (or a leading portion of a brush); and a trailing brush (or a trailing portion of the brush) and a trailing suction nozzle. The leading suction nozzle sucks free dirt, and the leading brush (or the leading portion of the brush) performs dry scrubbing for free dirt and adhered solidified dirt. The trailing brush (or the trailing portion of the brush) performs wet scrubbing in cooperation with the sprayed cleaning fluid, and the trailing suction nozzle performs suction for the mixture of the dirt and cleaning fluid. According to the present invention, the cleaning can be done more thoroughly.