The explicit finite element analysis method combined with the artificial transmitting boundary theory is performed to evaluate the adjacent terrain effects on ground motion,and the influence of the distance between ad...The explicit finite element analysis method combined with the artificial transmitting boundary theory is performed to evaluate the adjacent terrain effects on ground motion,and the influence of the distance between adjacent terrains on the topographical amplification effects on ground motion is studied. The results show that:( 1) Compared to the case of a single hill,the presence of adjacent hills has little effect on the shape of the spectral ratio curve,but has a significant effect on the value of spectral ratio,which is dependent on the locations of observation points.( 2) The presence of adjacent hills has a greater effect on high-frequency ground motion,and with the increase of the distance between adjacent hills,such an effect weakens gradually,and the effect of the composite topography combined with multiple hills on ground motion gradually approaches that of a single hill.展开更多
Gas-phase hydrogen abstraction reactions have been compared using the popular density functional theory （DFT） functional BHandHLYP/aug-cc-pVTZ/RECP level of theory, on the basis of the model reaction CHCI-/CCl2- ＋ ...Gas-phase hydrogen abstraction reactions have been compared using the popular density functional theory （DFT） functional BHandHLYP/aug-cc-pVTZ/RECP level of theory, on the basis of the model reaction CHCI-/CCl2- ＋ CX3H （X = F, Cl, Br and I）. Our theoretical findings suggest the efficiency of the H-abstraction reactions induced by either CHCl- or CCl2- increases as the substrate is changed from CF3H to Cl3H, and that CHCI＇-has a higher activity in hydrogen abstraction than CCl2- for a given substrate. The entropy effect at 298 K does not significantly change the trend in reactivity of the various reactions, which is in general controlled by the heights of activation energies △E＂. Therefore, we have explored the origin of the energy barriers △E＂ of the reactions using the activation strain model of chemical reactivity.展开更多
基金sponsored by the China National Special Fund for Earthquake Scientific Research in Public Interest(Grant No.201408002)Earthquake Science and Technology Spark Plan of China Earthquake Administration(XH14061Y)
文摘The explicit finite element analysis method combined with the artificial transmitting boundary theory is performed to evaluate the adjacent terrain effects on ground motion,and the influence of the distance between adjacent terrains on the topographical amplification effects on ground motion is studied. The results show that:( 1) Compared to the case of a single hill,the presence of adjacent hills has little effect on the shape of the spectral ratio curve,but has a significant effect on the value of spectral ratio,which is dependent on the locations of observation points.( 2) The presence of adjacent hills has a greater effect on high-frequency ground motion,and with the increase of the distance between adjacent hills,such an effect weakens gradually,and the effect of the composite topography combined with multiple hills on ground motion gradually approaches that of a single hill.
基金the Fundamental Research Funds for the Central Universities (zyz2011059)
文摘Gas-phase hydrogen abstraction reactions have been compared using the popular density functional theory （DFT） functional BHandHLYP/aug-cc-pVTZ/RECP level of theory, on the basis of the model reaction CHCI-/CCl2- ＋ CX3H （X = F, Cl, Br and I）. Our theoretical findings suggest the efficiency of the H-abstraction reactions induced by either CHCl- or CCl2- increases as the substrate is changed from CF3H to Cl3H, and that CHCI＇-has a higher activity in hydrogen abstraction than CCl2- for a given substrate. The entropy effect at 298 K does not significantly change the trend in reactivity of the various reactions, which is in general controlled by the heights of activation energies △E＂. Therefore, we have explored the origin of the energy barriers △E＂ of the reactions using the activation strain model of chemical reactivity.
