Propulsion of liquefied natural gas (LNG) ships is undergoing significant change. The traditional steam plant is losing favor because of its low cycle efficiency. Medium-speed diesel-electric and slow-speed diesel-mec...Propulsion of liquefied natural gas (LNG) ships is undergoing significant change. The traditional steam plant is losing favor because of its low cycle efficiency. Medium-speed diesel-electric and slow-speed diesel-mechanical drive ships are in service, and more are being built. Another attractive alternative is combined gas and steam turbine (COGAS) drive. This approach offers significant advantages over steam and diesel propulsion. This paper presents the case for the COGAS cycle.展开更多
Sorbitol is a primary platform compound in the conversion of cellulose.The conversion of sorbitol to C_(6) hydrocarbons requires a complete cleavage of C–O bonds and meanwhile the inhibition of C–C cleavage.Here,we ...Sorbitol is a primary platform compound in the conversion of cellulose.The conversion of sorbitol to C_(6) hydrocarbons requires a complete cleavage of C–O bonds and meanwhile the inhibition of C–C cleavage.Here,we demonstrated an efficient selective cleavage of C–O over C–C bond on the(221)facet of supported CoGa.A selectivity of 94%to C_(6) hydrocarbon with conversion of 97%has been achieved.The selective C–O cleavage was demonstrated by tuning the exposed facet as(221)or(110).The supported CoGa was prepared simply by reduction of Co and Ga-containing layered double hydroxides(CoZnGaAl-LDHs),the exposed facets of CoGa crystallites were controlled by tailoring the temperature-programmed rate in the reduction.By reducing CoZnGaAl-LDHs,CoGa(221)was exposed with a temperature-programmed rate of 5℃/min under the induction of ZnO lattice,while CoGa(110)was exposed with a rate of 10℃/min.展开更多
Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. T...Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. The sensor chip was prepared by a spin-coating technique which deposited a thin film of WO3 on an alumina substrate. The chip samples were then calcined at 300, 400, 500 or 600 ℃ for 1 h. The sensitivities of the different sensor chips for CO gas were determined by comparing the changes in electrical resistance in the absence and presence of 50 ppm of CO gas at 200 ℃. The WO3 calcined at 500 ℃ had the highest sensitivity. The sensitivity of this sensor was also measured at CO concentrations of 100 ppm and 200 ppm and at operating temperatures of 30 and 100℃. Thermogravimetric analysis of the WO3 calcined at 500 ℃ indicated that this sample had the highest gas adsorption capacity. This preliminary research has shown that WO3 can serve as a CO gas sensor and that is should be further explored and developed.展开更多
文摘Propulsion of liquefied natural gas (LNG) ships is undergoing significant change. The traditional steam plant is losing favor because of its low cycle efficiency. Medium-speed diesel-electric and slow-speed diesel-mechanical drive ships are in service, and more are being built. Another attractive alternative is combined gas and steam turbine (COGAS) drive. This approach offers significant advantages over steam and diesel propulsion. This paper presents the case for the COGAS cycle.
基金the National Natural Science Foundation of China(No.22108009)the National Key R&D Program of China(No.2017YFA0206804)are gratefully acknowledged..
文摘Sorbitol is a primary platform compound in the conversion of cellulose.The conversion of sorbitol to C_(6) hydrocarbons requires a complete cleavage of C–O bonds and meanwhile the inhibition of C–C cleavage.Here,we demonstrated an efficient selective cleavage of C–O over C–C bond on the(221)facet of supported CoGa.A selectivity of 94%to C_(6) hydrocarbon with conversion of 97%has been achieved.The selective C–O cleavage was demonstrated by tuning the exposed facet as(221)or(110).The supported CoGa was prepared simply by reduction of Co and Ga-containing layered double hydroxides(CoZnGaAl-LDHs),the exposed facets of CoGa crystallites were controlled by tailoring the temperature-programmed rate in the reduction.By reducing CoZnGaAl-LDHs,CoGa(221)was exposed with a temperature-programmed rate of 5℃/min under the induction of ZnO lattice,while CoGa(110)was exposed with a rate of 10℃/min.
文摘Carbon monoxide is a poisonous and hazardous gas and sensitive sensor devices are needed to prevent humans from being poisoned by this gas. A CO gas sensor has been prepared from WO3 synthesized by a sol-gel method. The sensor chip was prepared by a spin-coating technique which deposited a thin film of WO3 on an alumina substrate. The chip samples were then calcined at 300, 400, 500 or 600 ℃ for 1 h. The sensitivities of the different sensor chips for CO gas were determined by comparing the changes in electrical resistance in the absence and presence of 50 ppm of CO gas at 200 ℃. The WO3 calcined at 500 ℃ had the highest sensitivity. The sensitivity of this sensor was also measured at CO concentrations of 100 ppm and 200 ppm and at operating temperatures of 30 and 100℃. Thermogravimetric analysis of the WO3 calcined at 500 ℃ indicated that this sample had the highest gas adsorption capacity. This preliminary research has shown that WO3 can serve as a CO gas sensor and that is should be further explored and developed.
