Isospin-dependent Quantum Molecular Dynamics model (IQMD) has been applied to investigate the Pygmy Dipole Resonance (PDR) and Giant Dipole Resonance (GDR) in Ni isotopes by Coulomb excitation. By Gaussian fitting to ...Isospin-dependent Quantum Molecular Dynamics model (IQMD) has been applied to investigate the Pygmy Dipole Resonance (PDR) and Giant Dipole Resonance (GDR) in Ni isotopes by Coulomb excitation. By Gaussian fitting to the photon emission spectra, the peak energies and strengths of PDR and GDR are extracted. Their sensitivities to impact parameter, incident energy and the symmetry energy are discussed. By the comparison of energy-weighted sum rule (EWSR) with the data and other calculations for 68 Ni, the parameters of density-dependence of symmetry energy in the IQMD are constrained. In addition, the N/Z dependence of PDR and GDR parameters of Ni isotopes are investigated, and the results that the EWSR increases linearly with the N/Z are obtained.展开更多
The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC).The spin of maximal projectile-like fragment is found to depend st...The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC).The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence.Some interesting multi-fragmentation phenomena related to the spin are shown.We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC.展开更多
Shear viscosity (η) is a basic transport coefficient of the medium.In this work,we calculate shear viscosity to entropy density ratio (η/S) of an equilibrated system in intermediate energy heavy ion collisions withi...Shear viscosity (η) is a basic transport coefficient of the medium.In this work,we calculate shear viscosity to entropy density ratio (η/S) of an equilibrated system in intermediate energy heavy ion collisions within the framework of the Boltzmann-Uehling-Uhlenbeck model (BUU) model.After the equilibration of Au + Au system at central collision in a fixed volume is reached,temperature,pressure and energy density are extracted by the phase space information and then η/S is calculated using the Green-Kubo formulas.The results show that η/S drops with the incident energy and its value is not so drastically different from the RHIC results.展开更多
By extending the minimum spanning tree(MST)clusterization algorithm for the binding energy cut,the isospin asymmetry dependence of directed flow for isospin sensitive isobar pairs(neutrons-protons,3H-3He) is studied f...By extending the minimum spanning tree(MST)clusterization algorithm for the binding energy cut,the isospin asymmetry dependence of directed flow for isospin sensitive isobar pairs(neutrons-protons,3H-3He) is studied from low towards high incident energies.The modified clusterization method(MSTB) has the advantage to identify the fragments at quite early time.It enhances(reduces) the production of free nucleons(fragments) over MST method.The directed flow of isobaric pair3H-3He is more sensitive towards isospin asymmetry caused by MSTB than isobaric pair n-p.This sensitivity becomes quite strong towards the high incident energy and neutron-rich reaction system.In conclusion,the inclusion of binding energy in clusterization method for the flow studies has been uniquely important for understanding the isospin physics,especially for high density behavior of symmetry energy.展开更多
How the initial fluctuation affects on the elliptic flow is investigated by investigating the rapidity, transverse 4-velocity, centrality dependencies of elliptic flow for Au+Au at 1 GeV/A with the help of an Isospin ...How the initial fluctuation affects on the elliptic flow is investigated by investigating the rapidity, transverse 4-velocity, centrality dependencies of elliptic flow for Au+Au at 1 GeV/A with the help of an Isospin Quantum Molecular Dynamics (IQMD). In addition, we compare the flow calculated with respect to participant plane created by the initial geometry in coordinate space with the flow reconstructed by the experimental event-plane method, and compare the flow with the experimental data of the FOPI collaboration. It shows that there exists some discrepancy between the flows reconstructed by the above two methods.展开更多
The azimuthal distributions at mid-rapidity for ^(40)Ar-induced reactions are investigated by nuclear transport theory.The rotation-like behavior which is one of collective motions becomes stronger with the increasing...The azimuthal distributions at mid-rapidity for ^(40)Ar-induced reactions are investigated by nuclear transport theory.The rotation-like behavior which is one of collective motions becomes stronger with the increasing of the imp&ct parameter and weaker with the increasing of the projectile energy.At about 85 MeV/nucleon the rot&tion-like behvior aim os t vanishes for ^(40)Ar+^(27)Al system.While the rotation-like behavior becomes weaker and the out-of-plane enhancement of particle emisBion is revealed with the increasing of target mass.Some quantitative agreements with the experiment data are also obtained.展开更多
We developed a simple model to calculate the interaction radii for light neutron-rich nuclei based on Coulomb-modified Glauber model.Considering a relation of surface diffuseness of neutron distribution with the neutr...We developed a simple model to calculate the interaction radii for light neutron-rich nuclei based on Coulomb-modified Glauber model.Considering a relation of surface diffuseness of neutron distribution with the neutron separation energy of nucleus,the large increasing of nuclear interaction radii for exotic nuclei(such as ^(6)He,^(8)He,^(11)Li,^(11)Be)on ^(12)C target can be reasonably explained.展开更多
New calculations for the total reaction cross sections and production cross sections of the energetic particles are carried out via the nuclear transport theory.The ex-perimental total reaction cross sections cann be ...New calculations for the total reaction cross sections and production cross sections of the energetic particles are carried out via the nuclear transport theory.The ex-perimental total reaction cross sections cann be reproduced.In addition,the efects of some ingredients on the total reaction cross sections can be easily analyzed.It is found that the total reaction cross sections are sensitive to the nuclear equation of state bclow 100 MeV/u and the in-medium nicleon-ucleon cross section in the full energy range addressed.While the π-mcson production cross sections can be also calculated..展开更多
An improved microscopic model to calculate the initial exciton number has been developed on the basis of original microscopic model-so-called phase-space model.In our model the particle number p0 and hole number h0 ar...An improved microscopic model to calculate the initial exciton number has been developed on the basis of original microscopic model-so-called phase-space model.In our model the particle number p0 and hole number h0 are treated separately and the Vlasov or BUU dynamics is used during the nucleus-nucleus collision instead of simple dynamical process without friction.This model reproduces the experimental results rather well.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.11220101005,11035009,10979074 and 11205230)Major State Basic Research Development Program in China(No.2013CB834405)
文摘Isospin-dependent Quantum Molecular Dynamics model (IQMD) has been applied to investigate the Pygmy Dipole Resonance (PDR) and Giant Dipole Resonance (GDR) in Ni isotopes by Coulomb excitation. By Gaussian fitting to the photon emission spectra, the peak energies and strengths of PDR and GDR are extracted. Their sensitivities to impact parameter, incident energy and the symmetry energy are discussed. By the comparison of energy-weighted sum rule (EWSR) with the data and other calculations for 68 Ni, the parameters of density-dependence of symmetry energy in the IQMD are constrained. In addition, the N/Z dependence of PDR and GDR parameters of Ni isotopes are investigated, and the results that the EWSR increases linearly with the N/Z are obtained.
基金Partially supported by NSFC of China under contract No.11035009,No.10979074,No.10875160,No.10805067 and No.10975174the 973-Program under contract No.2007CB815004+1 种基金the Shanghai Development Foundation for Science and Technology under contract No.09JC1416800the Knowledge Innovation Project of CAS under Grant No.KJCX2-EW-N01
文摘The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC).The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence.Some interesting multi-fragmentation phenomena related to the spin are shown.We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC.
基金supported by the National Natural Science Foundation of China (No.11035009,10979074,10775168 and 10975174)Major State Basic Research Development Program in China (No.2007CB815004)+1 种基金Foundation for Developing Science and Technology in Shanghai (No. 09JC1416800)Knowledge Innovation Project of Chinese Academy ofSciences under (No. KJCX2-EW-N01)
文摘Shear viscosity (η) is a basic transport coefficient of the medium.In this work,we calculate shear viscosity to entropy density ratio (η/S) of an equilibrated system in intermediate energy heavy ion collisions within the framework of the Boltzmann-Uehling-Uhlenbeck model (BUU) model.After the equilibration of Au + Au system at central collision in a fixed volume is reached,temperature,pressure and energy density are extracted by the phase space information and then η/S is calculated using the Green-Kubo formulas.The results show that η/S drops with the incident energy and its value is not so drastically different from the RHIC results.
基金Supported by the Chinese Academy of Sciences Support program for young international scientists(No.2010Y2JB02)National Natural Science Foundation of China(NSFC) projects (Nos.11220101005,11035009 and 10979074)the Knowledge Innovation project of the Chinese Academy of Sciences(No.KJCX2-EW-N01)
文摘By extending the minimum spanning tree(MST)clusterization algorithm for the binding energy cut,the isospin asymmetry dependence of directed flow for isospin sensitive isobar pairs(neutrons-protons,3H-3He) is studied from low towards high incident energies.The modified clusterization method(MSTB) has the advantage to identify the fragments at quite early time.It enhances(reduces) the production of free nucleons(fragments) over MST method.The directed flow of isobaric pair3H-3He is more sensitive towards isospin asymmetry caused by MSTB than isobaric pair n-p.This sensitivity becomes quite strong towards the high incident energy and neutron-rich reaction system.In conclusion,the inclusion of binding energy in clusterization method for the flow studies has been uniquely important for understanding the isospin physics,especially for high density behavior of symmetry energy.
基金Supported by National Natural Science Foundation of China(Nos.11220101005,11035009,10979074 and 11205230)Major State Basic Research Development Program in China(No.2013CB834405)
文摘How the initial fluctuation affects on the elliptic flow is investigated by investigating the rapidity, transverse 4-velocity, centrality dependencies of elliptic flow for Au+Au at 1 GeV/A with the help of an Isospin Quantum Molecular Dynamics (IQMD). In addition, we compare the flow calculated with respect to participant plane created by the initial geometry in coordinate space with the flow reconstructed by the experimental event-plane method, and compare the flow with the experimental data of the FOPI collaboration. It shows that there exists some discrepancy between the flows reconstructed by the above two methods.
基金Supported by the National Natural Science Foundation of ChinaHeavy Ion Research Facility of Lanzhou。
文摘The azimuthal distributions at mid-rapidity for ^(40)Ar-induced reactions are investigated by nuclear transport theory.The rotation-like behavior which is one of collective motions becomes stronger with the increasing of the imp&ct parameter and weaker with the increasing of the projectile energy.At about 85 MeV/nucleon the rot&tion-like behvior aim os t vanishes for ^(40)Ar+^(27)Al system.While the rotation-like behavior becomes weaker and the out-of-plane enhancement of particle emisBion is revealed with the increasing of target mass.Some quantitative agreements with the experiment data are also obtained.
基金Supported by the National Natural Science Foundation of ChinaHeavy Ion Research Facility of Lanzhou.
文摘We developed a simple model to calculate the interaction radii for light neutron-rich nuclei based on Coulomb-modified Glauber model.Considering a relation of surface diffuseness of neutron distribution with the neutron separation energy of nucleus,the large increasing of nuclear interaction radii for exotic nuclei(such as ^(6)He,^(8)He,^(11)Li,^(11)Be)on ^(12)C target can be reasonably explained.
基金Supported by the National Natural Science Foundation of China,and Heavy Ion Research Facility of Lanzhou.
文摘New calculations for the total reaction cross sections and production cross sections of the energetic particles are carried out via the nuclear transport theory.The ex-perimental total reaction cross sections cann be reproduced.In addition,the efects of some ingredients on the total reaction cross sections can be easily analyzed.It is found that the total reaction cross sections are sensitive to the nuclear equation of state bclow 100 MeV/u and the in-medium nicleon-ucleon cross section in the full energy range addressed.While the π-mcson production cross sections can be also calculated..
文摘An improved microscopic model to calculate the initial exciton number has been developed on the basis of original microscopic model-so-called phase-space model.In our model the particle number p0 and hole number h0 are treated separately and the Vlasov or BUU dynamics is used during the nucleus-nucleus collision instead of simple dynamical process without friction.This model reproduces the experimental results rather well.
