The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulati...The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulations of ethane dehydrogenation over Co@BEA zeolite at different temperatures.AIMD simulations showed that a sharp decrease in free energy barrier as temperature increased.Our analysis of the temperature dependence of activation free energies uncovered an unusual entropic effect accompanying the reaction.The unique spatial structures around the Co active site at different temperatures influenced both the extent of charge transfer in the transition state and the arrangement of 3d orbital energy levels.We provided explanations consistent with the principles of thermodynamics and statistical physics.The insights gained at the atomic level have offered a fresh interpretation of the intricate long-range interplay between local chemical reactions and extensive chemical environments.展开更多
There are four main vitality states of human body in Traditional Chinese Medicine (TCM). Eye is the most important part on face for TCM doctors to diagnose patient. In this paper,we present several methods of eye quan...There are four main vitality states of human body in Traditional Chinese Medicine (TCM). Eye is the most important part on face for TCM doctors to diagnose patient. In this paper,we present several methods of eye quantification. We quantify eye movement,venation in white part of eye,tears in eye and the shape of upper eyelid,and then use cloud model to deduce volunteers' vitality condition by these measurements. We collect more than one thousand face images and dozens of face videos of patients',and some rules we mined with the highest support and interesting scores are right correspond to TCM diagnosis.展开更多
By system analysis and imitating modeling authors show the most effective modern techniques for railway electric systems control. Modem measure technologies PMU-WAMS and smart grid allow to solve real time tasks of ce...By system analysis and imitating modeling authors show the most effective modern techniques for railway electric systems control. Modem measure technologies PMU-WAMS and smart grid allow to solve real time tasks of centralizing control of railway electric systems. Quantity characteristics of control effectiveness are determined. According to computer modeling the situation approach is available for practical tasks of railway electric system control.展开更多
文摘The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulations of ethane dehydrogenation over Co@BEA zeolite at different temperatures.AIMD simulations showed that a sharp decrease in free energy barrier as temperature increased.Our analysis of the temperature dependence of activation free energies uncovered an unusual entropic effect accompanying the reaction.The unique spatial structures around the Co active site at different temperatures influenced both the extent of charge transfer in the transition state and the arrangement of 3d orbital energy levels.We provided explanations consistent with the principles of thermodynamics and statistical physics.The insights gained at the atomic level have offered a fresh interpretation of the intricate long-range interplay between local chemical reactions and extensive chemical environments.
基金National Natural Science Foundations of China (No.60873179, No.60672018)
文摘There are four main vitality states of human body in Traditional Chinese Medicine (TCM). Eye is the most important part on face for TCM doctors to diagnose patient. In this paper,we present several methods of eye quantification. We quantify eye movement,venation in white part of eye,tears in eye and the shape of upper eyelid,and then use cloud model to deduce volunteers' vitality condition by these measurements. We collect more than one thousand face images and dozens of face videos of patients',and some rules we mined with the highest support and interesting scores are right correspond to TCM diagnosis.
文摘By system analysis and imitating modeling authors show the most effective modern techniques for railway electric systems control. Modem measure technologies PMU-WAMS and smart grid allow to solve real time tasks of centralizing control of railway electric systems. Quantity characteristics of control effectiveness are determined. According to computer modeling the situation approach is available for practical tasks of railway electric system control.
