The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this wo...The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.展开更多
Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any pr...Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.展开更多
Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. W...Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. We find that： （i） with the cooperation of the electrostatic interactions between proteins and oxygen-containing groups, GO shows better adsorption stability than PG; （ii） the peptide loses its secondary structure on both PG and GO surface, and the a-helix structure of the protein fragment is partially broken on PG surface, but is well preserved on GO surface, while the secondary structure of globular protein has no distinct change on both PG and GO surface. In general, GO presents better biocompatibility than PG. Our results are of significant importance to understand the interactions between proteins and PG/GO and the applications of PG/GO in biotechnology and biomedicine.展开更多
The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial st...The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial state of thesystem and the relative coupling strength between the atom and the field on the atomic information entropy squeezingare discussed.Our results show that the squeezed direction and the frequency of the information entropy squeezing canbe controlled by choosing the phase of the atom dipole and the relative competing strength of atom-field,respectively.We find that,under the same condition,no atomic variance squeezing is predicted from the HUR while optimal entropysqueezing is obtained from the EUR,so the quantum information entropy is a remarkable precision measure for theatomic squeezing in the considered system.展开更多
Special proton-gradient-transfer acid complexes （PGTACs） in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the prot...Special proton-gradient-transfer acid complexes （PGTACs） in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the protons gave the PGTACs excellent catalytic activity and selectivity in the esterifica- tion of terpenols. These PGTACs are ＂reaction-induced self-separation catalysts＂ and can be easily reused. The kinetics with PGTACs as catalyst in the esterification of geraniol were also studied for use in engineering design.展开更多
Four-, six-, and eight-membered ring silica nanotubes at temperatures from 300 K to 1600 K are relaxed by classical molecular dynamics simulations with three potential models. The simulation results indicate that the ...Four-, six-, and eight-membered ring silica nanotubes at temperatures from 300 K to 1600 K are relaxed by classical molecular dynamics simulations with three potential models. The simulation results indicate that the stability of the end rings of the three silica nanotubes gradually decreases with increase in temperature. The validity of the vibrational features of silica nanotubes is shown by the vibrational density of states. Infrared spectra on the silica nanotubes under different temperatures are investigated. A detailed assignment of each spectral peak to the corresponding vibrational mode of the three nanotubes has been addressed. The results are in good agreement with the other theoretical and experimental展开更多
文摘The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.
文摘Mean-square bond length, root-mean-square end-to-end distance and gyration radius in diblock copolymer films have been studied by dissipative particle dynamics simulations. Results show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What＇s more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.
基金supported by the National Natural Science Foundation of China(No.61575178 and No.11574272)the Zhejiang Provincial Natural Science Foundation of China(No.LY16A040014 and LY18A040001)the Scientific Research and Developed Fund of Zhejiang A&F University(No.2015FR022)
文摘Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. We find that： （i） with the cooperation of the electrostatic interactions between proteins and oxygen-containing groups, GO shows better adsorption stability than PG; （ii） the peptide loses its secondary structure on both PG and GO surface, and the a-helix structure of the protein fragment is partially broken on PG surface, but is well preserved on GO surface, while the secondary structure of globular protein has no distinct change on both PG and GO surface. In general, GO presents better biocompatibility than PG. Our results are of significant importance to understand the interactions between proteins and PG/GO and the applications of PG/GO in biotechnology and biomedicine.
基金National Natural Science Foundation of China under Grant No:10374025the Education Department of Hunan Province of China under Grant No.06A038
文摘The entropy squeezing properties for a two-level atom interacting with a two-mode field via two differentcompeting transitions are investigated from a quantum information point of view.The influences of the initial state of thesystem and the relative coupling strength between the atom and the field on the atomic information entropy squeezingare discussed.Our results show that the squeezed direction and the frequency of the information entropy squeezing canbe controlled by choosing the phase of the atom dipole and the relative competing strength of atom-field,respectively.We find that,under the same condition,no atomic variance squeezing is predicted from the HUR while optimal entropysqueezing is obtained from the EUR,so the quantum information entropy is a remarkable precision measure for theatomic squeezing in the considered system.
基金supported by the National Natural Science Foundation of China (21376115, 21576129)~~
文摘Special proton-gradient-transfer acid complexes （PGTACs） in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the protons gave the PGTACs excellent catalytic activity and selectivity in the esterifica- tion of terpenols. These PGTACs are ＂reaction-induced self-separation catalysts＂ and can be easily reused. The kinetics with PGTACs as catalyst in the esterification of geraniol were also studied for use in engineering design.
文摘Four-, six-, and eight-membered ring silica nanotubes at temperatures from 300 K to 1600 K are relaxed by classical molecular dynamics simulations with three potential models. The simulation results indicate that the stability of the end rings of the three silica nanotubes gradually decreases with increase in temperature. The validity of the vibrational features of silica nanotubes is shown by the vibrational density of states. Infrared spectra on the silica nanotubes under different temperatures are investigated. A detailed assignment of each spectral peak to the corresponding vibrational mode of the three nanotubes has been addressed. The results are in good agreement with the other theoretical and experimental
