基于密度泛函理论,采用第一性原理计算方法研究了C,N,O原子在金属V中的扩散行为.首先,讨论了C,N,O原子在V体心立方晶格中的间隙占位情况,分析了其在间隙位置与V晶格的相互作用,并探究了这种相互作用对金属V电子结构的影响.研究结果表明:...基于密度泛函理论,采用第一性原理计算方法研究了C,N,O原子在金属V中的扩散行为.首先,讨论了C,N,O原子在V体心立方晶格中的间隙占位情况,分析了其在间隙位置与V晶格的相互作用,并探究了这种相互作用对金属V电子结构的影响.研究结果表明:C,N,O原子在V的八面体间隙位置更为稳定,并且C,N,O原子的2p电子与V的3d电子之间有比较强的成键作用;C,N,O原子的扩散势垒分别为0.89,1.26,0.98 e V,并得出了其扩散系数表达式;最后,通过阿仑尼乌斯关系图对比了三者在V中扩散系数的大小,并计算出体系温度在500—1100 K之间时其在V中的扩散系数,计算结果与实验值基本符合.展开更多
Ultrasonically assisted nitration reactions (USANR) with anilides, moderately activated and non-activated aromatic compounds underwent smoothly and afforded good yields of products with high regio selectivity. Observe...Ultrasonically assisted nitration reactions (USANR) with anilides, moderately activated and non-activated aromatic compounds underwent smoothly and afforded good yields of products with high regio selectivity. Observed longer reaction times (6 - 8 hrs.) in metal catalyzed reactions reduced to (1 - 2 hrs.) under sonication. When ortho position is blocked para derivatives are obtained, and ortho nitro products are obtained when para position is blocked. In case of USANR of aromatic carbonyl and related compounds the effect of sonication is much more effective. The reactions could be completed only in few minutes.展开更多
文摘基于密度泛函理论,采用第一性原理计算方法研究了C,N,O原子在金属V中的扩散行为.首先,讨论了C,N,O原子在V体心立方晶格中的间隙占位情况,分析了其在间隙位置与V晶格的相互作用,并探究了这种相互作用对金属V电子结构的影响.研究结果表明:C,N,O原子在V的八面体间隙位置更为稳定,并且C,N,O原子的2p电子与V的3d电子之间有比较强的成键作用;C,N,O原子的扩散势垒分别为0.89,1.26,0.98 e V,并得出了其扩散系数表达式;最后,通过阿仑尼乌斯关系图对比了三者在V中扩散系数的大小,并计算出体系温度在500—1100 K之间时其在V中的扩散系数,计算结果与实验值基本符合.
文摘Ultrasonically assisted nitration reactions (USANR) with anilides, moderately activated and non-activated aromatic compounds underwent smoothly and afforded good yields of products with high regio selectivity. Observed longer reaction times (6 - 8 hrs.) in metal catalyzed reactions reduced to (1 - 2 hrs.) under sonication. When ortho position is blocked para derivatives are obtained, and ortho nitro products are obtained when para position is blocked. In case of USANR of aromatic carbonyl and related compounds the effect of sonication is much more effective. The reactions could be completed only in few minutes.
