The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 11...The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 119 effective Skyrme interaction sets.The values of the correlation coefficients illustrate that the magnitude of effective mass splitting is crucial for tight constraints on the symmetry energy via heavy-ion collisions.The^(86)Kr+^(208)Pb system at beam energies ranging from 25 to 200A MeV was simulated within the framework of the improved quantum molecular dynamics model(ImQMD-Sky).Our calculations show that the slopes of the spectra of ln[Y(n)/Y(p)]and ln[Y(t)/Y(^(3)He)],which are the logarithms of the neutron to proton and triton to helium-3 yield ratios,are directly related to effective mass splitting and can be used to probe the effective mass splitting.展开更多
Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the iso...Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.展开更多
The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecu...The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.展开更多
A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the ...A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables,namely isospin transport ratios,single and double ratios of the yields of neutrons and protons are investigated.The isospin transport ratios are strongly sensitive to the slope of symmetry energy,and are not very sensitive to the nucleon effective mass splitting.On the other hand,the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting.By comparing our calculations with the data,we find that the constrained L value(the slope of density dependence of symmetry energy) is about ~46 MeV when the Skyrme type interaction is considered in transport models,and the isospin diffusion data prefer to mn*>mp*,but it is not a strong constraint with deep χ2minimum.展开更多
The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the f...The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the frequency dynamic progress in the island with large-capacity active-power shortage. In this paper, coupling effects of voltage and frequency are studied to indicate that initial reactive-power deficit and load characteristics have strong effects on the coupling effects of the voltage and frequency. Moreover, control effects of currently used under frequency load-shedding relays (UFLS) and under voltage load-shedding relays (UVLS) which are installed and executed independently are examined to find that it would sometimes cause excessive or inadequate control without considering the coupling, suggesting that it is necessary to develop coordinate control methods for voltage and frequency problems.展开更多
The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Ah...The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique. The periodic Anderson model is used to describe the quantum dot system, the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered. The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects. We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12275359,11875323,11961141003,U2032145,11890712)the National Key R&D Program of China(No.2018YFA0404404)+1 种基金the Continuous Basic Scientific Research Project(Nos.WDJC-2019-13 and BJ20002501)funding from the China Institute of Atomic Energy(No.YZ222407001301).
文摘The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 119 effective Skyrme interaction sets.The values of the correlation coefficients illustrate that the magnitude of effective mass splitting is crucial for tight constraints on the symmetry energy via heavy-ion collisions.The^(86)Kr+^(208)Pb system at beam energies ranging from 25 to 200A MeV was simulated within the framework of the improved quantum molecular dynamics model(ImQMD-Sky).Our calculations show that the slopes of the spectra of ln[Y(n)/Y(p)]and ln[Y(t)/Y(^(3)He)],which are the logarithms of the neutron to proton and triton to helium-3 yield ratios,are directly related to effective mass splitting and can be used to probe the effective mass splitting.
基金Supported by National Natural Science Foundation of China(NSFC) projects (No.11175218)the Advancement Society of Young Innovation of Chinese Academy of Sciences
文摘Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.
基金the National Natural Science Foundation of China(Nos.11905018 and 11875328)the Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province,China(No.2019L0908)。
文摘The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.
基金Supported by National Natural Science Foundation of China(NSFC) projects (Nos.11075215,10875031,11005022,11005155 and 11275052)973 Program of China(No.2013CB834404)National Science Foundation(Grants No.PHY-0606007)
文摘A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables,namely isospin transport ratios,single and double ratios of the yields of neutrons and protons are investigated.The isospin transport ratios are strongly sensitive to the slope of symmetry energy,and are not very sensitive to the nucleon effective mass splitting.On the other hand,the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting.By comparing our calculations with the data,we find that the constrained L value(the slope of density dependence of symmetry energy) is about ~46 MeV when the Skyrme type interaction is considered in transport models,and the isospin diffusion data prefer to mn*>mp*,but it is not a strong constraint with deep χ2minimum.
文摘The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the frequency dynamic progress in the island with large-capacity active-power shortage. In this paper, coupling effects of voltage and frequency are studied to indicate that initial reactive-power deficit and load characteristics have strong effects on the coupling effects of the voltage and frequency. Moreover, control effects of currently used under frequency load-shedding relays (UFLS) and under voltage load-shedding relays (UVLS) which are installed and executed independently are examined to find that it would sometimes cause excessive or inadequate control without considering the coupling, suggesting that it is necessary to develop coordinate control methods for voltage and frequency problems.
基金Project supported by the Natural Science Foundation of Heilongjiang Province,China (Grant No. F200939)
文摘The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique. The periodic Anderson model is used to describe the quantum dot system, the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered. The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects. We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.
