A new approach to calculate the potential acting on an electron in a molecule（PAEM） has been established for drawing the molecular face（MF） of a macromolecule, according to the classic point charge model and the a...A new approach to calculate the potential acting on an electron in a molecule（PAEM） has been established for drawing the molecular face（MF） of a macromolecule, according to the classic point charge model and the atom-bond electronegativity equalization method（ABEEMσπ） for one electron in a molecule. We introduced a dy- namic charge distribution from the view of a local electron movement in a molecule based on the new approach, and as further direct evidence, we calculated some physical quantities using the original ab initio method and the new method to verify the accuracy of the method, such as the boundary distance（BD）, molecular face surface area（MFSA） and molecular reactivities indicated by the MFs for a variety of organic molecules. All the results by the new method are in agreement with the results by ab initio method.展开更多
Since 1980’s,life science has been holding a prominent place in the development ofscience and it is expected to become one of the leading disciplines in the 21 century.Currently the development of life science presen...Since 1980’s,life science has been holding a prominent place in the development ofscience and it is expected to become one of the leading disciplines in the 21 century.Currently the development of life science presents the following characteristics:1.The understanding of life was deepened to the molecule level.展开更多
Classical molecular dynamics has been used to study the interactions between tung- sten （W） plasma-facing materials （PFMs） and dust grains. The impact velocity of dust grains is in the range from 324 m/s to 3240 m...Classical molecular dynamics has been used to study the interactions between tung- sten （W） plasma-facing materials （PFMs） and dust grains. The impact velocity of dust grains is in the range from 324 m/s to 3240 m/s. The main effect of dust grains with low impact velocity is deposition. However, a material surface can be damaged by high velocity dust grains. The cumulative damage of impacting dust grains has also been take into account. When the impact velocity is low, no significant damage is detected but a porous firm forms on the surface. Serious damage can be produced on PFMs if the impact velocity is high.展开更多
The dynamical progresses involved in ultra-short laser pulse ablation of face-centered cubic metals under stress confinement condition are described completely using molecular dynamics method. The laser beam absorptio...The dynamical progresses involved in ultra-short laser pulse ablation of face-centered cubic metals under stress confinement condition are described completely using molecular dynamics method. The laser beam absorption and thermal energy turning into kinetics energy of. atoms are taken into account to give a detailed picture of laser metal interaction. Superheating phenomenon is observed, and the phase change from solid to liquid is characterized by a destroyed atom configuration and a decreased number density. The steep velocity gradients are found in the systems of Cu and Ni after pulse in consequence of located heating and exponential decrease of fluences following the Lambert-Beer expression. The shock wave velocities are predicted to be about 5 000 m/s in Cu and 7 200 m/s in Ni. The higher ablation rates are obtained from simulations compared with experimental data as a result of a well-defined crystalline surface irradiated by a single pulse. Simulation results show that the main mechanisms of ablation are evaporation and thermoelastic stress due to located heating.展开更多
基金Supported by the National Natural Science Foundation of China（Nos.21473083, 21133005）.
文摘A new approach to calculate the potential acting on an electron in a molecule（PAEM） has been established for drawing the molecular face（MF） of a macromolecule, according to the classic point charge model and the atom-bond electronegativity equalization method（ABEEMσπ） for one electron in a molecule. We introduced a dy- namic charge distribution from the view of a local electron movement in a molecule based on the new approach, and as further direct evidence, we calculated some physical quantities using the original ab initio method and the new method to verify the accuracy of the method, such as the boundary distance（BD）, molecular face surface area（MFSA） and molecular reactivities indicated by the MFs for a variety of organic molecules. All the results by the new method are in agreement with the results by ab initio method.
文摘Since 1980’s,life science has been holding a prominent place in the development ofscience and it is expected to become one of the leading disciplines in the 21 century.Currently the development of life science presents the following characteristics:1.The understanding of life was deepened to the molecule level.
基金supported by National Natural Science Foundation of China(No.11075186)National Magnetic Confinement Fusion Science Program of China(No.2013GB107004)
文摘Classical molecular dynamics has been used to study the interactions between tung- sten （W） plasma-facing materials （PFMs） and dust grains. The impact velocity of dust grains is in the range from 324 m/s to 3240 m/s. The main effect of dust grains with low impact velocity is deposition. However, a material surface can be damaged by high velocity dust grains. The cumulative damage of impacting dust grains has also been take into account. When the impact velocity is low, no significant damage is detected but a porous firm forms on the surface. Serious damage can be produced on PFMs if the impact velocity is high.
基金the Ministerial Level Advanced Research Foundation (ABAQ440261)
文摘The dynamical progresses involved in ultra-short laser pulse ablation of face-centered cubic metals under stress confinement condition are described completely using molecular dynamics method. The laser beam absorption and thermal energy turning into kinetics energy of. atoms are taken into account to give a detailed picture of laser metal interaction. Superheating phenomenon is observed, and the phase change from solid to liquid is characterized by a destroyed atom configuration and a decreased number density. The steep velocity gradients are found in the systems of Cu and Ni after pulse in consequence of located heating and exponential decrease of fluences following the Lambert-Beer expression. The shock wave velocities are predicted to be about 5 000 m/s in Cu and 7 200 m/s in Ni. The higher ablation rates are obtained from simulations compared with experimental data as a result of a well-defined crystalline surface irradiated by a single pulse. Simulation results show that the main mechanisms of ablation are evaporation and thermoelastic stress due to located heating.
