Abstract: Disclosed is a heat exchanger. The heat exchanger includes a plurality of plates superimposed on one another, and a plurality of heat transfer fins formed on the plurality of plates, and shaped into an airfoil, wherein a channel of a fluid between the superimposed plates is formed to perform a heat exchange.

Abstract: The present invention relates to a process for preparing thiomethylphenol derivatives, and particularly to a simple process of preparing thiophenol derivatives by performing a reaction of a phenol derivative, a mercaptan derivative and paraformaldehyde in a solvent in the presence of a given amount of heterocyclic amine base and acids, thereby capable of maintaining a mild reaction condition and providing thiomethylphenol derivatives with an improved discoloration by purification using acids.

Abstract: The present invention relates to a process for preparing thiomethylphenol derivatives, and particularly to a simple process of preparing thiophenol derivatives by performing a reaction of a phenol derivative, a mercaptan derivative and paraformaldehyde in a solvent in the presence of a given amount of heterocyclic amine base and acids, thereby capable of maintaining a mild reaction condition and providing thiomethylphenol derivatives with an improved discoloration by purification using acids.

Abstract: 4-aminodiphenylamine is prepared by reacting carbanilide and nitrobenzene in an adequate solvent, which may be nitrobenzene, in the presence of an appropriate organic base, which may be tetramethylammonium hydroxide, alone or in mixture with an inorganic base and subsequently reducing the reaction product in the presence of an appropriate catalyst and hydrogen gas. The subsequent reduction may be carried out on the reaction mixture before the reaction mixture is subjected to separation.

Abstract: 4-aminodiphenylamine is prepared by reacting carbanilide and nitrobenzene in an adequate solvent, which may be nitrobenzene, in the presence of an appropriate organic base, which may be tetramethylammonium hydroxide, alone or in mixture with an inorganic base and subsequently reducing the reaction product in the presence of an appropriate catalyst and hydrogen gas. The subsequent reduction may be carried out on the reaction mixture before the reaction mixture is subjected to separation.

Abstract: A method for forming a polycrystalline silicon thin film transistor. The method includes the steps of: forming a polycrystalline silicon layer including multiple protrusions by crystallizing the amorphous silicon layer according to a crystallization method in which the multiple protrusions are formed due to collision between crystal grains; patterning the polycrystalline silicon layer in an active pattern which includes only two protrusions of the multiple protrusions, which are apart from each other and located at both sides of a gate electrode-forming area; applying a barrier layer on the patterned polycrystalline silicon layer while partially covering the two protrusions; and forming a source electrode and a drain electrode at the protrusions of the polycrystalline silicon layer formed at both sides of the gate electrode-forming area by ion-implanting dopants into a resultant lamination.

Abstract: Disclosed is a method for forming a polycrystalline silicon film by crystallizing an amorphous silicon film. A mask has first to third shot regions having the same length. The first to third shot regions have transmission sections and non-transmission sections, which are alternately aligned. The transmission sections of the first shot region are positioned corresponding to the non-transmission sections of the second shot region, the non-transmission sections of the first shot region are positioned corresponding to the transmission sections of the second shot region, and the transmission sections of the third shot region are aligned corresponding to center portions of the transmission sections of the first and second shot regions. Primary to nth laser irradiation processes are performed with respect to the glass substrate, thereby crystallizing the amorphous silicon film into the polycrystalline silicon film.

Abstract: Disclosed herein is a method for forming a polycrystalline (poly-Si) film by the crystallization of an amorphous silicon film using laser light irradiation. The disclosed method comprises the steps of: sequentially depositing a buffer film and an amorphous silicon film on a glass substrate; depositing a metal film having laser light reflection function on the back side of the glass substrate; and irradiating the front side of the amorphous silicon film with laser light to crystallize the amorphous silicon film. In the laser light irradiation step, the irradiated laser light is absorbed into the amorphous silicon film, and a portion of the absorbed laser light is transmitted through the amorphous silicon film. The transmitted light is reflected from the metal film and absorbed into the amorphous silicon film again, thus crystallizing the amorphous silicon film twice over.

Abstract: Disclosed is a method for forming a polycrystalline silicon film of a polycrystalline silicon thin film transistor. The method includes a step of crystallizing an amorphous silicon film deposited on a glass substrate by irradiating a laser beam onto the amorphous silicon film using a mask pattern. The glass substrate is horizontally moved by a predetermined distance unit corresponding to a translation distance of the mask pattern when the laser beam is irradiated onto the amorphous silicon film through a mask having the mask pattern, thereby growing grains in a circular shape.

Abstract: Disclosed is a synthesis method of cyclohexyl phenyl ketone with a high selectivity and a high yield from 1,3-butadiene and acrylic acid in the presence or absence of benzene or a non-aromatic organic solvent in the same reaction without a step of separating or purifying intermediates, the synthesis method including sequentially carrying out a [2+4] Diels-Alder reaction, a hydrogenation reaction, a chlorination reaction and a Friedel-Crafts reaction in the presence/absence of benzene or a non-aromatic organic solvent without separation of intermediates.

Abstract: Disclosed is a synthesis method of cyclohexyl phenyl ketone with a high selectivity and a high yield from 1,3-butadiene and acrylic acid in the presence or absence of benzene or a non-aromatic organic solvent in the same reaction without a step of separating or purifying intermediates, the synthesis method including sequentially carrying out a [2+4] Diels-Alder reaction, a hydrogenation reaction, a chlorination reaction and a Friedel-Crafts reaction in the presence/absence of benzene or a non-aromatic organic solvent without separation of intermediates.

Abstract: Disclosed is a method for preparing a 4-nitroso-substituted aromatic amine that includes contacting an amide compound with a nitroaromatic compound in the presence of a base and a solvent to directly prepare 4-nitroso-substituted aromatic amine as a main product and 4-nitro-substituted aromatic amine as a by-product without producing 4-nitroso- or 4-nitro-substituted amide as an intermediate.

Abstract: A disclosed method of preparing p-phenylenediamine includes the steps of: reacting urea and nitrobenzene with a base in the presence of a polar solvent to yield 4-nitrosoaniline and 4-nitroaniline; and subsequently, diluting the resulting mixed solution in an alcohol and performing hydrogenation using a catalyst, thereby providing highly pure p-phenylenediamine destitute of an ortho- or meta-isomer as a byproduct. The method has some advantages in that: the process is simplified in such a manner that the hydrogenation is performed in the presence of the hydrogenation catalyst in a single reactor (i.e., one pot) without a need of isolating 4-nitrosoaniline or purifying the product; inexpensive urea and an alkali base are used to reduce the production cost; and 4-nitrosoaniline is formed as an intermediate to yield p-phenylenediamine with a high selectivity, thereby requiring no purification process after isolation of the product.

Abstract: A method for preparing 4-nitrosoaniline, including reacting urea and nitrobenzene in a polar organic solvent in the presence of a base at a temperature of room temperature to 150° C. The method uses a relatively cheap urea and nitrobenzene as the raw materials, and also a relatively cheap base, thereby decreasing the manufacturing cost. Urea used as an amine donor is excellent in a reactivity to nitrobenzene, and a reaction intermediate is unstable as compared with 4-(4-nitrophenyl)benzamide to easily decompose into 4-nitroaniline and 4-nitrosoaniline. This allows a reaction time and a process time to be shortened. Moreover, the method is advantageous in that waste hazardous to the environment is not produced as a byproduct.

Abstract: A method for preparing 4,4'-dinitrodiphenylamine, including reacting urea and nitrobenzene in a polar organic solvent in the presence of a base at a temperature of room temperature to 100.degree. C. The method employs a relatively cheap urea and nitrobenzene as the raw materials, and also employs a relatively cheap base, thereby decreasing the manufacturing costs. Moreover, the method does not produce by-products, thus eliminating a need for a post-treating process. Additionally, the method is advantageous in that the production of 4,4'-dinitrodiphenylamine can be achieved in high yield and selectivity even under non-intensive reaction conditions by appropriately controlling the amounts of urea and nitrobenzene.

Abstract: This invention relates to a process for preparing 4-nitrodiphenylamine and 4-nitrosodiphenylamine to be used for 4-aminodiphenylamine as an intermediate of antiozonant, wherein carbanilide is reacted with nitrobenzene in the presence of an appropriate base, while simultaneously adding aniline to the mixture so as to regenerate some amounts of carbanilide as a starting material.According to this invention, 4-nitrodiphenylamine and 4-nitrosodiphenylamine can be prepared in a higher selectivity and conversion rate via a continuous reaction by recycling carbanilide, a starting material, while adding a certain amount of aniline during the process. Further, the amount of waste water can be significantly reduced compared to the conventional method without any corrosive materials harmful to the environment.

Abstract: A method for preparing 2-methyl-1,4-naphthoquinone (vitamin K.sub.3), in which 2-methyl-1,4-benzoquinone and 1,3-butadienes are subjected to a ?2+4! Diels-Alder reaction and subsequently to oxidative dehydrogenation, using dimethylsulfoxide as both a dehydrogenating agent and a solvent in the presence of at least one Lewis acid or a Broensted acid, in a single pot, shows high selectivity and yield.

Abstract: A method for preparing anthraquinones, by which 1,4-benzoquinone or 1,4-naphthoquinone and 1,3-butadienes are subjected to a ?2+4! Diels-Alder reaction and subsequently to oxidative dehydrogenation by using dimethylsulfoxide as a dehydrogenating agent in a single pot in the presence of a Lewis acid or Broensted acid shows high selectivity and yield.