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Dynamical fluctuations in fragmentation reactions in a Boltzmann-Langevin approach

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Communications in Theoretical Physics 2022年第11期74卷 140-150页

作者： Bing Li Na Tang feng-shou zhang Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of LanzhouLanzhou 730000China

Based on the isospin-dependent Boltzmann-Langevin model,the dynamical fluctuations in the fragmentation reaction of^(112)Sn+^(112)Sn are *** quadrupole moment and octupole moment with zero magnetic quantum number have large fluctuations in the early time of the *** dynamical fluctuations in momentum space show a strong dependence on the incident *** effects of using different fluctuations on the fragment cross sections are also studied in the fragmentation *** results by using Q_(20)+Q_(30)fluctuation have a better agreement with the experimental *** using Q_(20)+Q_(30)fluctuation produce more proton-rich and neutron-rich nuclei than those using Q_(20)fluctuation ***,the difference between the production cross sections of fragments calculated by using Q_(20)and Q_(20)+Q_(30)fluctuations is larger in the vicinity of the *** results present that the dynamical fluctuations may affect the whole dynamical process of fragmentation reactions including the production of fragments,due to the nonlinear nature of the Boltzmann-Langevin equation.

关键词： fragmentation reactions the isospin-dependent Boltzmann-Langevin model dynamical fluctuations

Constraining nuclear symmetry energy with the charge radii of mirror-pair nuclei

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Nuclear Science and Techniques 2023年第8期34卷 154-163页

作者： Rong An Shuai Sun Li-Gang Cao feng-shou zhang Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Key Laboratory of Beam Technology of Ministry of Education Institute of Radiation TechnologyBeijing Academy of Science and TechnologyBeijing 100875China CAS Key Laboratory of High Precision Nuclear Spectroscopy Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of LanzhouLanzhou 730000China

The nuclear charge radius plays a vital role in determining the equation of state of isospin asymmetric nuclear *** on the correlation between the differences in charge radii of mirror-partner nuclei and the slope parameter(L)of symmetry energy at the nuclear saturation density,an analysis of the calibrated slope parameter L was performed in finite *** this study,relativistic and nonrelativistic energy density functionals were employed to constrain the nuclear symmetry energy through the available databases of the mirror-pair nuclei^(36)Ca–^(36)S,^(38)Ca–^(38)Ar,and ^(54)Ni–^(54)*** deduced nuclear symmetry energy was located in the range 29.89–31.85 MeV,and L of the symmetry energy essentially covered the range 22.50–51.55 MeV at the saturation ***,the extracted L_(s) at the sensitivity density p_(s)=0.10 fm^(-3) was located in the interval range 30.52–39.76 MeV.

关键词： Symmetry energy Charge radii Mirror nuclei

New quantification of symmetry energy from neutron skin thicknesses of^(48)Ca and^(208)Pb

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Nuclear Science and Techniques 2024年第10期35卷 188-196页

作者： Rong An Shuai Sun Li-Gang Cao feng-shou zhang School of Physics Ningxia UniversityYinchuan 750021China Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Key Laboratory of Beam Technology of the Ministry of Education Institute of Radiation TechnologyBeijing Academy of Science and TechnologyBeijing 100875China Center of Theoretical Nuclear Physics National Laboratory of the Heavy Ion Accelerator of LanzhouLanzhou 730000China

Precise knowledge of the nuclear symmetry energy can be tentatively calibrated using multimessenger *** neutron skin thickness of a heavy nucleus is one of the most sensitive indicators for probing the isovector components of effective interactions in asymmetric nuclear *** studies have suggested that the experimental data from the CREX and PREX2 collaborations are not mutually compatible with existing nuclear *** this study,we review the quantification of the slope parameter of the symmetry energy L from the neutron skin thicknesses of^(48)Ca and^(208)*** energy density functionals classified by various isoscalar incompressibility coefficients K were employed to evaluate the bulk properties of finite *** calculated results suggest that the slope parameter L deduced from^(208)Pb is sensitive to the compression modulus of symmetric nuclear matter,but not that from^(48)*** effective parameter sets classified by K=220 MeV can provide an almost overlapping range of L from^(48)Ca and^(208)Pb.

关键词： Nuclear symmetry energy Neutron skin thickness Energy density functional

Ethylene glycol solution-induced DNA conformational transitions

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Chinese Physics B 2018年第11期27卷 445-458页

作者： Nan zhang Ming-Ru Li feng-shou zhang Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing 100875 China Beijing Radiation Center Beijing 100875 China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator ofLanzhou Lanzhou 730000 China

We study the properties of the ethylene glycol solutions and the conformational transitions of DNA segment in the ethylene glycol solutions by molecular dynamics simulations based on GROMACS. The hydrogen network structures of water–water and ethylene glycol–water are reinforced by ethylene glycol molecules when the concentrations of the solutions increase from 0% to 80%. As illustrated by the results, conformation of the double-stranded DNA in ethylene glycol solutions, although more compact, is similar to the structure of DNA in the aqueous solutions. In contrast, the DNA structure is an A–B hybrid state in the ethanol/water mixed solution. A fraying of terminal base-pairs is observed for the terminal cytosine. The ethylene glycol molecules preferentially form a ring structure around the phosphate groups to influence DNA conformation by hydrogen interactions, while water molecules tend to reside in the grooves. The repulsion between the negatively charged phosphate groups is screened by ethylene glycol molecules, preventing the repulsion from unwinding and extending the helix and thus making the conformation of DNA more compact.

关键词： DNA conformational transitions ethylene glycol molecular dynamics simulations

A simulation study of water property changes using geometrical alteration in SPC/E

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Chinese Physics B 2018年第8期27卷 204-211页

作者： Ming-Ru Li Nan zhang feng-shou zhang Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education of China and College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875China Beijing Radiation Center Beijing 100875China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of LanzhouLanzhou 730000China

We present a systematic investigation of the impact of changing the geometry structure of the SPC/E water model by performing a series of molecular dynamic simulations at 1 bar （1 bar = 105 Pa） and 298.15 K. The geometric modification includes altering the H-O-H angle range from 90° to 115° and modifying the O-H length range from 0.90 A to 1.10 A in the SPC/E model. The former is achieved by keeping the dipole moment constant by modifying the O-H length, while in the latter only the O-H length is changed. With the larger bond length and angle, we find that the liquid shows a strong quadrupole interaction and high tetrahedral structure order parameter, resulting in the enhancement of the network structure of the liquid. When the bond length or angle is reduced, the hydrogen bond lifetime and self-diffusion constant decrease due to the weakening of the intermolecular interaction. We find that modifying the water molecular bond length leading to the variation of the intermolecular interaction strength is more intensive than changing the bond angle. Through calculating the average reduced density gradient and thermal fluctuation index, it is found that the scope of vdW interaction with neighbouring water molecules is inversely proportional to the change of the bond length and angle. The effect is mainly due to a significant change of the hydrogen bond network. To study the effect of water models as a solvent whose geometry has been modified, the solutions of ions in different solvent environments are examined by introducing NaCI. During the dissolving process, NaCI ions are ideally dissolved in SPC/E water and bond with natural water more easily than with other solvent models.

关键词： molecular dynamics simulation geometric modification intermolecular interaction ion's solva-tion

Investigation of multinucleon transfer processes in the Langevin equation model

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Nuclear Science and Techniques 2024年第10期35卷 180-187页

作者： Ying Zou Ming-Hao zhang Mei-Chen Wang Yu-Hai zhang feng-shou zhang The Key Laboratory of Beam Technology of Ministry of Education School of Physics and AstronomyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of LanzhouLanzhou 730000China

Multinucleon transfer in low-energy heavy-ion collisions is increasingly considered a promising approach for generating exotic *** the complex mechanisms involved in multinucleon transfer processes presents significant challenges for the theoretical investigation of nuclear reactions.A Langevin equation model was developed and employed to investigate multinucleon transfer ***^(40)Ar+^(232)Th reaction was simulated,and the calculated Wilczyński plot was used to verify the ***,to study the dynamics of multinucleon transfer reactions,the^(136)Xe+^(238)U and^(136)Xe+^(209)Bi reactions were simulated,and the corresponding TKE-mass and angular distributions were computed to analyze the energy dissipation and scattering *** investigation enhances our understanding of the dynamics involved in multinucleon transfer processes.

关键词： Reaction mechanisms Multinucleon transfer reactions Langevin equations Wilczyński plot Exotic nuclei

Enhancement in optical absorption of CsI(Na)

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Nuclear Science and Techniques 2022年第3期33卷 53-61页

作者： Wei Cheng Pei-Sheng Liu Min-Ju Ying feng-shou zhang Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China National Laboratory of Heavy Ion Accelerator of Lanzhou Center of Theoretical Nuclear PhysicsLanzhou 730000China

Discussions pertaining to enhancement in the luminous efficiency of cesium iodide(CsI)detectors doped with sodium(Na)*** this study,the defect structure of one Cs atom replaced by one Na atom is calculated using the ab initio ***,the electronic band structures,densities of states,optical absorption spectra,phonons,and transport properties of CsI in perfect and defective structures are *** absorption spectra of CsI with and without Na impurities are *** is discovered that the impurity levels in the forbidden band are generated from the shell electron distributions of the impurity atoms,not from lattice ***,it is discovered that the optical absorption can be enhanced by doping CsI with Na.

关键词： CsI Na impurity Band structure Phonon Absorption spectrum

Micro-Raman investigations on the structures of the surface and the inner of MgSO_4 droplets

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Chinese Science Bulletin 2008年第15期53卷 2414-2416页

作者： WANG feng shou JingJing zhang YunHong The Institute of Chemical Physics Beijing Institute of Technology Beijing 100081 China

Spherical MgSO4 droplets were deposited by a syringe on the hydrophobic Teflon substrate. Using micro-Raman technique, the laser beam was highly focused twice on the surface and in the center of spherical droplets. The Raman spectra for the surface and the inner of MgSO4 droplets were accord-ingly obtained, suggesting formation of a thin layer of gels on MgSO4 droplets at low relative humidity. The gel layer covered the surface and exhibited a significant delay in response to the change of ambi-ent relative humidity, resulting in the structural difference between the surface and the inner of MgSO4 droplets.

关键词： MgSO4滴液凝胶结构表面结构群体传输

Production cross sections for exotic nuclei with multinucleon transfer reactions

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Frontiers of physics 2018年第6期13卷 181-196页

作者： feng-shou zhang Cheng Li Long Zhu Peiwei Wen The Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing 100875 China Beijing Radiation Center Beijing 100875 China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai 519082 China China Institute of Atomic Energy Beijing 102413 China

The main progresses in the multinucleon transfer reactions at energies close to the Coulomb barrier are reviewed. After a short presentation of the experimental progress and theoretical progress, the predicted product... 详细信息

关键词： heavy-ion collisions multinucleon transfer reactions exotic nuclei GRAZING model DNS model ImQMD model