Abstract: The present invention relates to: a catalyst for glycerin dehydration; a preparation method therefor; and an acrolein preparation method using the catalyst. According to one embodiment of the present invention, the catalyst is used in glycerin dehydration so as to exhibit high catalytic activity, a high yield and high acrolein selectivity, and has a characteristic in which carbon is not readily deposited, thereby having a long lifetime compared with that of a conventional catalyst.

Abstract: A method of fabricating a semiconductor light-emitting device is provided that includes forming a first conductivity-type semiconductor layer, forming an active layer by alternately forming a plurality of quantum well layers grown at a first temperature and a plurality of quantum barrier layers grown at a second temperature higher than the first temperature, and forming a second conductivity-type semiconductor layer.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein. The catalyst for glycerin dehydration exhibits a high glycerin conversion ratio, minimizes by-product formation to improve acrolein selectivity, and also maintains high catalytic activity during reaction.

Abstract: The invention relates to a reactor system, comprising a heat-exchange unit and a reaction unit that are assembled together into a structure. The heat-exchange unit has a plurality of plate or corrugated-plate heat exchangers, and is formed so as to attachable/detachable to/from the reaction unit and insertable into the latter. Accordingly, a catalyst may be attached to a heat-transfer surface of a heat exchanger by a washcoat method or the like, thus maximizing heat-transfer efficiency and enabling the easy removal or reattachment of the catalyst when the enabling the easy removal or reattachment of the catalyst at the end of the lifespan of the catalyst.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein, and more particularly, to a catalyst for glycerin dehydration which minimizes by-product formation during glycerin dehydration to improve acrolein selectivity and maintains high catalytic activity during reaction.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein, and more particularly, to a catalyst for glycerin dehydration which minimizes by-product formation to improve acrolein selectivity and maintains high catalytic activity during reaction.

Abstract: The present invention relates to a method for preparing a catalyst for glycerin dehydration, a catalyst for glycerin dehydration prepared thereby, and a method for preparing acrolein. More particularly, the catalyst for glycerin dehydration prepared by the preparation method is able to minimize by-product formation to improve acrolein selectivity and to maintain high catalytic activity during the reaction.

Abstract: The present invention relates to: a catalyst activation method for Fischer-Tropsch synthesis; a catalyst regeneration method for Fischer-Tropsch synthesis; and a method for producing a liquid or solid hydrocarbon by using the Fischer-Tropsch synthesis reaction. The temperatures required for a metal carbide producing and activating reaction is markedly lower than existing catalyst activation temperatures, and the catalyst can be activated under conditions that are the same as Fischer-Tropsch synthesis reaction conditions, and thus there is no need for separate reduction equipment in the reactor, and a Fischer-Tropsch synthesis catalyst which has been used for a long time can be regenerated within the reactor without the catalyst being isolated or extracted from the reactor.

Abstract: The present invention relates to a method for preparing a catalyst for glycerin dehydration, a catalyst for glycerin dehydration prepared thereby, and a method for preparing acrolein. More particularly, the catalyst for glycerin dehydration prepared by the preparation method is able to minimize by-product formation to improve acrolein selectivity and to maintain high catalytic activity during the reaction.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein. The catalyst for glycerin dehydration exhibits a high glycerin conversion ratio, minimizes by-product formation to improve acrolein selectivity, and also maintains high catalytic activity during reaction.

Abstract: A method of manufacturing a nitride semiconductor light emitting device which includes forming an n-type semiconductor layer, forming an active layer on the n-type semiconductor layer, forming a superlattice layer by alternately stacking at least two nitride layers made of InxAlyGa(1-x-y)N (0?x?1, 0?y?1, and 0?x+y?1) having different energy bandgaps from each other and doped with a p-type dopant, and forming a p-type semiconductor layer on the superlattice layer. The forming of the superlattice layer is performed by adjusting a flow rate of a p-type dopant source gas to reduce the flow rate in a growth termination period of the superlattice layer by no greater than about half of the flow rate in a growth initiation period of the superlattice layer while being doped with the p-type dopant.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein, and more particularly, to a catalyst for glycerin dehydration which minimizes by-product formation to improve acrolein selectivity and maintains high catalytic activity during reaction.

Abstract: The present invention relates to a catalyst for glycerin dehydration, a preparation method thereof, and a preparation method of acrolein, and more particularly, to a catalyst for glycerin dehydration which minimizes by-product formation during glycerin dehydration to improve acrolein selectivity and maintains high catalytic activity during reaction.

Abstract: A semiconductor light emitting device includes a first conductive semiconductor layer including a V-shaped recess in a cross-sectional view. An active layer is disposed on the first conductive semiconductor layer, conforming to the shape of the V-shaped recess. An intermediate layer is disposed on the active layer and is doped with a first impurity. A second conductive semiconductor layer is disposed on the intermediate layer. The intermediate layer includes a first intermediate layer and a second intermediate layer. The first intermediate layer is disposed on the active layer, conforming to the shape of the V-shape recess. The second intermediate layer is disposed on the first intermediate layer and includes a protrusion to fill the V-shaped recess.

Abstract: The present invention relates to a catalyst for Fischer-Tropsch synthesis which has excellent heat transfer capability. This catalyst contains (1) central core particle or particles made of a heat transfer material (HTM) selected from the group consisting of a metal, a metal oxide, a ceramic, and a mixture thereof; and (2) outer particle layer which surrounds the central core particles and is attached to the surfaces of the central core particles by a binder material layer. The outer particle layer has a support and catalyst particles in a powder form containing metal particles disposed on the support. The catalyst having such a dual particle structure shows excellent heat transfer capability and, thus, exhibits high selectivity to a target hydrocarbon. Therefore, the catalyst of the present invention is useful in a fixed-bed reactor for Fischer-Tropsch synthesis for producing hydrocarbons from synthetic gas.

Abstract: A method of manufacturing a nitride semiconductor light emitting device which includes forming an n-type semiconductor layer, forming an active layer on the n-type semiconductor layer, forming a superlattice layer by alternately stacking at least two nitride layers made of InxAlyGa(1-x-y)N (0?x?1, 0?y?1, and 0?x+y?1) having different energy bandgaps from each other and doped with a p-type dopant, and forming a p-type semiconductor layer on the superlattice layer. The forming of the superlattice layer is performed by adjusting a flow rate of a p-type dopant source gas to reduce the flow rate in a growth termination period of the superlattice layer by no greater than about half of the flow rate in a growth initiation period of the superlattice layer while being doped with the p-type dopant.

Abstract: The present invention relates to: a catalyst activation method for Fischer-Tropsch synthesis; a catalyst regeneration method for Fischer-Tropsch synthesis; and a method for producing a liquid or solid hydrocarbon by using the Fischer-Tropsch synthesis reaction. The temperatures required for a metal carbide producing and activating reaction is markedly lower than existing catalyst activation temperatures, and the catalyst can be activated under conditions that are the same as Fischer-Tropsch synthesis reaction conditions, and thus there is no need for separate reduction equipment in the reactor, and a Fischer-Tropsch synthesis catalyst which has been used for a long time can be regenerated within the reactor without the catalyst being isolated or extracted from the reactor.

Abstract: A method of manufacturing a nitride semiconductor light emitting device which includes forming an n-type semiconductor layer, forming an active layer on the n-type semiconductor layer, forming a superlattice layer by alternately stacking at least two nitride layers made of InxAlyGa(1-x-y)N (0?x?1, 0?y?1, and 0?x+y?1) having different energy bandgaps from each other and doped with a p-type dopant, and forming a p-type semiconductor layer on the superlattice layer. The forming of the superlattice layer is performed by adjusting a flow rate of a p-type dopant source gas to reduce the flow rate in a growth termination period of the superlattice layer by no greater than about half of the flow rate in a growth initiation period of the superlattice layer while being doped with the p-type dopant.

Abstract: The invention relates to a reactor system, comprising a heat-exchange unit and a reaction unit that are assembled together into a structure. The heat-exchange unit has a plurality of plate or corrugated-plate heat exchangers, and is formed so as to attachable/detachable to/from the reaction unit and insertable into the latter. Accordingly, a catalyst may be attached to a heat-transfer surface of a heat exchanger by a washcoat method or the like, thus maximizing heat-transfer efficiency and enabling the easy removal or reattachment of the catalyst when the enabling the easy removal or reattachment of the catalyst at the end of the lifespan of the catalyst.

Abstract: The present invention relates to a catalyst for Fischer-Tropsch synthesis which has excellent heat transfer capability. This catalyst contains (1) central core particle or particles made of a heat transfer material (HTM) selected from the group consisting of a metal, a metal oxide, a ceramic, and a mixture thereof; and (2) outer particle layer which surrounds the central core particles and is attached to the surfaces of the central core particles by a binder material layer. The outer particle layer has a support and catalyst particles in a powder form containing metal particles disposed on the support. The catalyst having such a dual particle structure shows excellent heat transfer capability and, thus, exhibits high selectivity to a target hydrocarbon. Therefore, the catalyst of the present invention is useful in a fixed-bed reactor for Fischer-Tropsch synthesis for producing hydrocarbons from synthetic gas.