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A possible proton pygmy resonance in ^(17)Ne

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 49-52页

作者： MA ZhongYu1,2.& TIAN Yuan1 1 China Institute of Atomic Energy, Beijing 102.13, China 2.center of theoretical nuclear physics, national laboratory of heavy collision,{2., China China Institute of Atomic Energy Beijing China center of theoretical{2. physics National Laboratory of Heavy Collision Lanzhou China

The low-lying electric dipole strengths in proton-rich nuclei 17F and 17Ne, which can be produced at HIRFL-CSR in lanzhou, are investigated. In the framework of the covariant density functional theory the self-consistent relativistic Hartree Bogoliubov model and the relativistic quasiparticle random phase approximation with the NL3 parameter set and Gogny pairing interaction are adopted in the calculations. A pronounced dipole peak appears below 10 MeV in17Ne, but does not occur in 17F. The prop erties of this low-lying E1 excitation in 17Ne are studied, which may correspond to a proton pygmy resonance with different characteristics from those of giant dipole resonance.

关键词： proton pygmy resonance relativistic Hartree-Bogoliubov model relativistic quasiparticle random phase approximation

Higher order bulk characteristic parameters of asymmetric nuclear matter

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 124-129页

作者： CHEN LieWen1,2.1Department of physics, Shanghai Jiao Tong University, Shanghai 2.02.0, China 2.1} of{2. nuclear physics, national laboratory of heavy Ion Accelerator, lanzhou 730000, China Department of physics Shanghai Jiao Tong University Shanghai China center of theoretical{2. physics National Laboratory of Heavy Ion Accelerator Lanzhou China

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-355±95) MeV and I0 = (1473±680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (2.4 ± 385) MeV, Isym = (-1309 ± 2.2.) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2.0 while the symmetry energy up to 2.0 can be well described by Esym(ρ0), L, and Ksym.

关键词： equations of state of nuclear matter forces in hadronic systems and effective interactions symmetry energy nuclear density functional theory and extensions asymmetric matter neutron matter

collision dynamics of He@C_(60)+He@C_(60) at low energies

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Science China(physics,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1,2. ZHANG FengShou1,2.3 & ZHOU HongYu1,2.1 Key laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy nuclear{2., Beijing Normal University, Beijing 100875, China 2.Beijing Radiation center, Beijing 100875, China 3 center of theoretical nuclear{2., national laboratory of heavy Ion Accelerator of lanzhou,{12., China Key laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China Beijing Radiation center Beijing China center of theoretical{2. physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52.Fe

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Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2.& LONG GuiLu1,2.1 Department of physics,Tsinghua University,Beijing 100084,China 2.center of{2. Theory,national laboratory of heavy Ion Accelerator of lanzhou,lanzhou 730000,China Department of physics Tsinghua University Beijing China center of nuclear Theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12. is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52.e neutron-proton interaction

The low-lying rotational bands of the neutron-rich nucleus ^(172.Tm

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Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1542-1547页

作者： CHEN BaoRen1,LI Tao1 & LIU ShuXin1,2.1 School of physics,Peking University,Beijing 100871,China 2.center of theoretical nuclear physics,{2. laboratory of heavy Ion collisions,lanzhou 730000,China School of physics Peking University Beijing China center of theoretical{2. physics National Laboratory of Heavy Ion Collisions Lanzhou China

The microscopic mechanism of four experimentally observed bands in 172.m is investigated using the particle-number conserving method of the cranked shell model with monopole and quadrupole paring *** experimental results,including the moments of inertia and angular momentum alignments of four bands in 172.m are reproduced well by the particle-number conserving *** ω variation of the occupation probability of each cranked orbital and the contribution to moment of inertia from each cranked orbital are *** unobserved low-lying bands of 2.quansiparticles in 172.m are predicted.

关键词： neutron-rich nucleus rare earth rotational band

Simple Formula of β^+-Decay Half-Lives of Nuclei Far From β-Stable Line

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Communications in theoretical physics 2007年第12期48卷 1072-1080页

作者： ZHANG Xiao-Ping~1 REN Zhong-Zhou~(1,2.and ZHI Qi-Jun~1~1 Department of physics,Nanjing University,Nanjing 2.0008,China~2.center of theoretical nuclear physics,{2. laboratory of heavy-Ion Accelerator,lanzhou 730000,China Department of physics Nanjing University Nanjing 210008 China center of theoretical{2. physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

We generalize the formula of β^+-decay half-lives [***.C 78 (2.06) 014305] to include all availabledata of nuclei far from the β-stable line. Good agreement with experimental data is obtained by taking into accountthe even-odd (e-o) *** is shown that the e-o effect on β^+-deeay half-life is apparent for the allowed β^+-transition,whereas it is not apparent for the first and second forbidden *** demonstrates that the allowed β^+-transitionis more sensitive to the nuclear even-odd effect than the forbidden β^+-*** underlying physics is *** formula can be used to predict the β^+-decay half-lives of the nuclei far from β-*** is useful to experimentalphysicists for analyzing the data of β^+-decay.

关键词： β^+-decay half-lives formula even-odd effect

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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Science China(physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2.3 1. China Institute of Atomic Energy, Beijing 102.13, China 2. center of nuclear{2. physics, national laboratory of heavy Ion Accelerator of lanzhou, Lan-zhou 730000, China 3. Institute of{2. physics, Chinese Academy of Sciences, Beijing 100080, China Correspondence should be addressed to Rong Jian (email: jrong@***) China Institute of Atomic Energy Beijing China center of nuclear{2. physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China Institute of theoretical physics Chinese Academy of Sciences Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.

Criterion for reducible hydrodynamic equations of baryon-rich quark-gluon plasma

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nuclear Science and Techniques 2000年第1期11卷 41-44页

作者： AI Xiao-Bai (Hsiao-bat AI) (center of theoretical{2. physics, national laboratory of heavy Ion Accelerator, lanzhou 730000 Shanghai Institule of{2. Research, the Chinese Academy of Sciences, Shanghai 2.1800) 兰州原子核理论研究中心重离子加速器国家实验室甘肃兰州 730000

Besides the state equation there exists another cubic algebraic equation about μf in the form of μf3 + pμf + q = 0, which relates parameters, temperature T, chemical potential μf, and net quark number nff （flavor f） for a baryon-rich quark-gluon plasma （QGP）. A criterion may be acquired simply according to Cardan formula of the solution of the above equation, which gives naturally a condition: if n 2.T3/3, one may approximately use the conservation of specific entropy, and then the set of hydrodynamic equation of baryon-rich QGP may be reduced to the set of hydrodynamic equation for baryon-free QGP.

关键词：重子夸克胶子粒子物理学简化流体动力学方程等离子体 QGP

Eigenvalues of Large Matrices

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原子核物理评论 2009年第S1期26卷 165-167页

作者： ZHAO Yu-min1,2.(1 Department of physics, Shanghai Jiaotong University, Shanghai 2.02.0,China 2.center of theoretical nuclear physics,{2. laboratory of heavy Ion Research Facility in lanzhou, lanzhou 730000, China)

We recently performed a series of improvement on evaluation of eigenvalues without complicated iterations. In this work we first discuss evaluation of the lowest eigenvalue for given systems,by which one conveniently obtains the value of the lowest eigenvalue based on the dimension and width of given matrix. We also discuss a strong correlation between eigenvalues and diagonal matrix elements for large matrices,by which one is able to predict eigenvalues approximately without iterations.

关键词： eigenvalue large matrix correlation