The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions am...The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions among polymer monomers are focused. Extensive simulations show that the dependence of diffusion coefficient D on the polymer concentration c agrees with Phillies equation D-exp （-αc^δ） with a scaling exponent δ≈0.97 which coincides with the experimental one in literature. For increasing nanoparticle size, the scaling prefactor α increases monotonically while the scaling exponent always keeps fixed. Moreover, we also study the diffusion of nanoparticle without hydrodynamic interactions and find that mobility of the nanoparticle slows down, and the scaling exponent is obviously different from the one in experiments, implying that hydrodynamic interactions play a crucial role in the diffusion of a nanoparticle in semidilute polymer solutions.展开更多
Hot,dense plasmas exhibit screened Coulomb interactions,resulting from the collective effects of correlated many-particle interactions.In the lowest particle correlation order(pair-wise correlations),the interaction b...Hot,dense plasmas exhibit screened Coulomb interactions,resulting from the collective effects of correlated many-particle interactions.In the lowest particle correlation order(pair-wise correlations),the interaction between charged plasma particles reduces to the DebyeeHu¨ckel(Yukawa-type)potential,characterized by the Debye screening length.Due to the importance of Coulomb interaction screening in dense laboratory and astrophysical plasmas,hundreds of theoretical investigations have been carried out in the past few decades on the plasma screening effects on the electronic structure of atoms and their collision processes employing the DebyeeHu¨ckel screening model.The present article aims at providing a comprehensive review of the recent studies in atomic physics in Debye plasmas.Specifically,the work on atomic electronic structure,photon excitation and ionization,electron/positron impact excitation and ionization,and excitation,ionization and charge transfer of ion-atom/ion collisions will be reviewed.展开更多
The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed.The st...The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed.The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombi-nation spectroscopy and VUV/x-ray spectroscopy.The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region,ion-induced fragmentation mechanisms of molecules,hydrogen-bound and van de Waals bound clusters,interference,and phase information observed in ion-atom/molecule collisions.With this achievements,two aspects of theoretical studies related to low energy and relativistic energy collisions are presented.The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed.At the end of this review,some future prospects of research related to highly charged ions are proposed.展开更多
We investigate the stability and collision dynamics of dissipative matter-wave solitons formed in a quasi-one- dimensional Bose-Einstein condensate with linear gain and three-body recombination loss perturbed by a wea...We investigate the stability and collision dynamics of dissipative matter-wave solitons formed in a quasi-one- dimensional Bose-Einstein condensate with linear gain and three-body recombination loss perturbed by a weak optical lattice. It is shown that the linear gain can modify the stability of the single dissipative soliton moving in the optical lattice. The collision dynamics of two individual dissipative matter-wave solitons explicitly depend on the linear gain parameter, and they display different dynamical behaviors in both the in-phase and out-of-phase interaction regimes.展开更多
In this review we discuss the recent progress in the simulation of soft active matter systems and in particular the hydrodynamics of microswimmers using the method of multiparticle collision dynamics,which solves the ...In this review we discuss the recent progress in the simulation of soft active matter systems and in particular the hydrodynamics of microswimmers using the method of multiparticle collision dynamics,which solves the hydrodynamic flows around active objects on a coarse-grained level.We first present a brief overview of the basic simulation method and the coupling between microswimmers and fluid.We then review the current achievements in simulating flexible and rigid microswimmers using multiparticle collision dynamics,and briefly conclude and discuss possible future directions.展开更多
By employing atomistic simulations based on an empirical potential model and a self-consistent-charge density-functional tight-binding method, the collision dynamics process of an energetic carbon ion impinging on the...By employing atomistic simulations based on an empirical potential model and a self-consistent-charge density-functional tight-binding method, the collision dynamics process of an energetic carbon ion impinging on the Stone-Wales defect in a single-walled carbon nanotube was investigated. The outwardly and inwardly displacement threshold energies for the primary knock-on atom in the Stone-Wales defect were calculated to be 24.0 and 25.0 eV, respectively. The final defect configuration for each case was a 5-1DB-T（DB=dangling bond） defect formed in the front surface of the nanotube. Moreover, the minimum incident energy of the projectile prompting the primary knock-on atom displacement was predicted to be 71.0 eV, and the time evolutions of the kinetic and potential energies of the projectile and the primary knock-on atom were both plotted to analyze the energy transfer process.展开更多
The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset fron...The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset frontal vehicle-to-vehicle collision. A unique 6-degree-of- freedom （6-DOF） vehicle dynamics/crash mathematical model and a simplified lumped mass occupant model are developed. The first model is used to define the vehicle body crash parameters and it integrates a vehicle dynamics model with a vehicle front-end structure model. The second model aims to predict the effect of VDCS on the kinematics of the occupant. It is shown from the numerical simulations that the vehicle dynamics/crash response and occupant behaviour can be captured and analysed quickly and accurately. Yurthermore, it is shown that the VDCS can affect the crash characteristics positively and the occupant behaviour is improved.展开更多
Conformation and dynamical evolution of block copolymers in shear flow is an important topic in polymer physics that underscores the forming process of various materials.We explored deformation and dynamics of copolym...Conformation and dynamical evolution of block copolymers in shear flow is an important topic in polymer physics that underscores the forming process of various materials.We explored deformation and dynamics of copolymers composed of rigid or flexible blocks in simple shear flow by employing multiparticle collision dynamics integrated with molecular dynamics simulations.We found that compared with the proportion between rigid and flexible blocks,the type of the central blocks plays more important role in the conformational and dynamical evolution of copolymers.That is,if the central block is a coil,the copolymer chain takes end-over-end tumbling motion,while if the central block is a rod,the copolymer chain undergoes U-shape or S-shape deformation at mid shear rate.As the shear strength increases,all copolymers behave similar to flexible polymers at high shear rate.This can be attributed to the fact that shear flow is strong enough to overcome the buckling force of the rigid blocks.These results provide a deeper understanding of the roles played by rod and coil blocks in copolymers for phase interface during forming processing.展开更多
We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We inclu...We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.展开更多
文摘The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions among polymer monomers are focused. Extensive simulations show that the dependence of diffusion coefficient D on the polymer concentration c agrees with Phillies equation D-exp （-αc^δ） with a scaling exponent δ≈0.97 which coincides with the experimental one in literature. For increasing nanoparticle size, the scaling prefactor α increases monotonically while the scaling exponent always keeps fixed. Moreover, we also study the diffusion of nanoparticle without hydrodynamic interactions and find that mobility of the nanoparticle slows down, and the scaling exponent is obviously different from the one in experiments, implying that hydrodynamic interactions play a crucial role in the diffusion of a nanoparticle in semidilute polymer solutions.
基金Wang was supported by the National Basic Research Program of China(Grant No.2013CB922200).
文摘Hot,dense plasmas exhibit screened Coulomb interactions,resulting from the collective effects of correlated many-particle interactions.In the lowest particle correlation order(pair-wise correlations),the interaction between charged plasma particles reduces to the DebyeeHu¨ckel(Yukawa-type)potential,characterized by the Debye screening length.Due to the importance of Coulomb interaction screening in dense laboratory and astrophysical plasmas,hundreds of theoretical investigations have been carried out in the past few decades on the plasma screening effects on the electronic structure of atoms and their collision processes employing the DebyeeHu¨ckel screening model.The present article aims at providing a comprehensive review of the recent studies in atomic physics in Debye plasmas.Specifically,the work on atomic electronic structure,photon excitation and ionization,electron/positron impact excitation and ionization,and excitation,ionization and charge transfer of ion-atom/ion collisions will be reviewed.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0402300)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB34020000)the Heavy Ion Research Facility in Lanzhou (HIRFL)
文摘The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed.The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombi-nation spectroscopy and VUV/x-ray spectroscopy.The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region,ion-induced fragmentation mechanisms of molecules,hydrogen-bound and van de Waals bound clusters,interference,and phase information observed in ion-atom/molecule collisions.With this achievements,two aspects of theoretical studies related to low energy and relativistic energy collisions are presented.The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed.At the end of this review,some future prospects of research related to highly charged ions are proposed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11547125 and 11465008the Hunan Provincial Natural Science Foundation under Grant Nos 2015JJ4020 and 2015JJ2114the Scientific Research Fund of Hunan Provincial Education Department under Grant No 14A118
文摘We investigate the stability and collision dynamics of dissipative matter-wave solitons formed in a quasi-one- dimensional Bose-Einstein condensate with linear gain and three-body recombination loss perturbed by a weak optical lattice. It is shown that the linear gain can modify the stability of the single dissipative soliton moving in the optical lattice. The collision dynamics of two individual dissipative matter-wave solitons explicitly depend on the linear gain parameter, and they display different dynamical behaviors in both the in-phase and out-of-phase interaction regimes.
基金This project acknowledges funding from the Austrian Science Fund(FWF)through a Lise-Meitner Fellowship(Grant No.M 2458-N36)。
文摘In this review we discuss the recent progress in the simulation of soft active matter systems and in particular the hydrodynamics of microswimmers using the method of multiparticle collision dynamics,which solves the hydrodynamic flows around active objects on a coarse-grained level.We first present a brief overview of the basic simulation method and the coupling between microswimmers and fluid.We then review the current achievements in simulating flexible and rigid microswimmers using multiparticle collision dynamics,and briefly conclude and discuss possible future directions.
基金Supported by the National Natural Science Foundation of China（Nos. 11505003, 11505092）, the Natural Science Foundation of Anhui Province, China（No. 1608085 QA20）, the Postdoctoral Science Foundation of Anhui Province, China（No.2016B091） and the Introduced Doctor＇s Startup Fund from Anhui University of Science and Technology, China（No.ZX944）.
文摘By employing atomistic simulations based on an empirical potential model and a self-consistent-charge density-functional tight-binding method, the collision dynamics process of an energetic carbon ion impinging on the Stone-Wales defect in a single-walled carbon nanotube was investigated. The outwardly and inwardly displacement threshold energies for the primary knock-on atom in the Stone-Wales defect were calculated to be 24.0 and 25.0 eV, respectively. The final defect configuration for each case was a 5-1DB-T（DB=dangling bond） defect formed in the front surface of the nanotube. Moreover, the minimum incident energy of the projectile prompting the primary knock-on atom displacement was predicted to be 71.0 eV, and the time evolutions of the kinetic and potential energies of the projectile and the primary knock-on atom were both plotted to analyze the energy transfer process.
基金the Egyptian government and the Faculty of Engineering,Ain Shams University for supporting this research
文摘The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset frontal vehicle-to-vehicle collision. A unique 6-degree-of- freedom （6-DOF） vehicle dynamics/crash mathematical model and a simplified lumped mass occupant model are developed. The first model is used to define the vehicle body crash parameters and it integrates a vehicle dynamics model with a vehicle front-end structure model. The second model aims to predict the effect of VDCS on the kinematics of the occupant. It is shown from the numerical simulations that the vehicle dynamics/crash response and occupant behaviour can be captured and analysed quickly and accurately. Yurthermore, it is shown that the VDCS can affect the crash characteristics positively and the occupant behaviour is improved.
基金supported by the National Natural Science Foundation of China(Nos.21774128,U1832177)Key Research Program of Frontier Sciences(No.QYZDY-SSWSLH027)NSFC Resource and Ecology Based Synthetic Polymeric Materials(No.51988102)。
文摘Conformation and dynamical evolution of block copolymers in shear flow is an important topic in polymer physics that underscores the forming process of various materials.We explored deformation and dynamics of copolymers composed of rigid or flexible blocks in simple shear flow by employing multiparticle collision dynamics integrated with molecular dynamics simulations.We found that compared with the proportion between rigid and flexible blocks,the type of the central blocks plays more important role in the conformational and dynamical evolution of copolymers.That is,if the central block is a coil,the copolymer chain takes end-over-end tumbling motion,while if the central block is a rod,the copolymer chain undergoes U-shape or S-shape deformation at mid shear rate.As the shear strength increases,all copolymers behave similar to flexible polymers at high shear rate.This can be attributed to the fact that shear flow is strong enough to overcome the buckling force of the rigid blocks.These results provide a deeper understanding of the roles played by rod and coil blocks in copolymers for phase interface during forming processing.
文摘We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.
