Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=...Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=1-8） clusters are systematically investigated and compared with those of pure silver clusters. The optimized structures show that the transition point from preferentially planar to three-dimensional structure occurs at n = 6 for the AgnAu clusters, and at n = 5 for AgnCu clusters. For different-sized AgnX clusters, one X （X=Au or Cu） atom substituted Agn＋l structure is a dominant growth pattern. The calculated fragmentation energies, second-order differences in energies, and the highest occupied molecular orbital-lowest unoccupied molecular orbital （HOMO LUMO） energy gaps show interesting odd-even oscillation behaviours, indicating that Ag2,4,6,s and Agl,3,5,7X （X=Au, Cu） clusters keep high stabilities in comparison with their neighbouring clusters. The natural population analysis reveals that the charges transfer from the Agn host to the impurity atom except for the Ag2Cu cluster. Moreover, vertical ionization potential （VIP）, vertical electronic affinity （VEA）, and chemical hardness （η） are discussed and compared in depth. The same odd even oscillations are found for the VIP and η of the AgnX （X=Au, Cu; n=1-8） clusters.展开更多
Nitrogen monoxide(NO) emitted from automobile exhaust and other industrial sources contributes largely to a variety of environmental problems, such as the formation of acid rain and photochemical smog Therefore, the c...Nitrogen monoxide(NO) emitted from automobile exhaust and other industrial sources contributes largely to a variety of environmental problems, such as the formation of acid rain and photochemical smog Therefore, the catalytic reduction of NO has become one of the urgent environmental issues In the present study, a series of Au/Mn 2O 3/Al 2O 3 catalysts, with different Mn 2O 3 loadings, were prepared by deposition precipitation The crystallite size of Au before and after reaction was characterized by XRD The activity of catalysts in the selective catalytic reduction of NO using propane in the presence of oxygen was evaluated It is found that the catalytic activity of Au/Mn 2O 3/Al 2O 3 is higher than that of Au/Al 2O 3 and Cu ZSM 5 at feed gas(0 6%NO+1 2%C 3H 8+5%O 2+He) and GHSV 5?000?h展开更多
The silicon epitaxial wafter for X band double Read-type DDR IMPATT diodes has been fabricatedby normal-low pressure growth technique. The hyperabrupt impurity profile and very thin p-layer, n-layerwere achieved.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10774103 and 10974138)
文摘Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=1-8） clusters are systematically investigated and compared with those of pure silver clusters. The optimized structures show that the transition point from preferentially planar to three-dimensional structure occurs at n = 6 for the AgnAu clusters, and at n = 5 for AgnCu clusters. For different-sized AgnX clusters, one X （X=Au or Cu） atom substituted Agn＋l structure is a dominant growth pattern. The calculated fragmentation energies, second-order differences in energies, and the highest occupied molecular orbital-lowest unoccupied molecular orbital （HOMO LUMO） energy gaps show interesting odd-even oscillation behaviours, indicating that Ag2,4,6,s and Agl,3,5,7X （X=Au, Cu） clusters keep high stabilities in comparison with their neighbouring clusters. The natural population analysis reveals that the charges transfer from the Agn host to the impurity atom except for the Ag2Cu cluster. Moreover, vertical ionization potential （VIP）, vertical electronic affinity （VEA）, and chemical hardness （η） are discussed and compared in depth. The same odd even oscillations are found for the VIP and η of the AgnX （X=Au, Cu; n=1-8） clusters.
文摘Nitrogen monoxide(NO) emitted from automobile exhaust and other industrial sources contributes largely to a variety of environmental problems, such as the formation of acid rain and photochemical smog Therefore, the catalytic reduction of NO has become one of the urgent environmental issues In the present study, a series of Au/Mn 2O 3/Al 2O 3 catalysts, with different Mn 2O 3 loadings, were prepared by deposition precipitation The crystallite size of Au before and after reaction was characterized by XRD The activity of catalysts in the selective catalytic reduction of NO using propane in the presence of oxygen was evaluated It is found that the catalytic activity of Au/Mn 2O 3/Al 2O 3 is higher than that of Au/Al 2O 3 and Cu ZSM 5 at feed gas(0 6%NO+1 2%C 3H 8+5%O 2+He) and GHSV 5?000?h
文摘The silicon epitaxial wafter for X band double Read-type DDR IMPATT diodes has been fabricatedby normal-low pressure growth technique. The hyperabrupt impurity profile and very thin p-layer, n-layerwere achieved.
