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The stability, geometry and electronic structure of the title nanoclusters were compared by using density functional theory (DFT) calculations. Their electrical property analysis showed that the relative magnitude of the HOMO-LUMO gaps (eV) that are average values from the calculated results with five different DFT functionals is as follows: B12N12(7:02)>Al12N12(4.09)>B12P12(3.80)>Al12P12(3.39). Computing the standard enthalpy and the Gibbs free energy of formation, it was found that the B(12)N(12) structure is thermodynamically stable at 298 K and 1 atmosphere of pressure, while the Al(12)N(12) structure may be stable at low temperatures. Due to positive values of change of enthalpy and entropy of formation for both the B(12)P(12) and Al(12)P(12) clusters, it seems that their formation from the consisting atoms is not spontaneous at any temperature. 相似文献
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An efficient synthesis of 12-hetero steroids was achieved via a Baeyer-Villiger oxidation and a photolysis as the key steps. We set out to describe in this paper the first synthesis of 12-aza steroids. The characteristic 1H and 13C NMR spectroscopic features of the synthesized compounds are reported. 相似文献
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The photosensitised oxidation of four substituted methyl oleates (12,13-epoxy, 12-hydroxy, 12-oxo, and 12-bromo) has been studied. The expected hydroperoxides were isolated by chromatography and indentified by spectroscopic procedure. 相似文献
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Synthesis of RNA in t 12 -t 12 mouse embryos 总被引:1,自引:0,他引:1
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Volume Contents
Contents Volume 12 相似文献20.