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Frontiers of physics 2020年第4期15卷 133-151页

作者： Yong-Jia Wang qing-feng li School of Science Huzhou UniversityHuzhou 313000China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

The equation of state(EOS)of nuclear matter,i.e.,the thermodynamic relationship between the binding energy per nucleon,temperature,density,as well as the isospin asymmetry,has been a hot topic in nuclear physics and astrophysics for a long *** knowledge of the nuclear EOS is essential for studying the propertics of muclei,the structure of neutron stars,the dynamics of heavy ion collision(HIC),as well as neutron star *** offers a unique way to create muclear matter with high density and isospin asymmetry in terrestrial laboratory,but the formed dense nuclear matter exists only for a very short period,one cannot measure the nuclear EOS directly in ***,transport models which often incorporate phenomenological potentials as an input are utilized to deduce the EOS from the comparison with the observables mcasured in *** ultrarelativistic quantum molecular dynamics(UrQMD)model has been widely employed for investigating HIC from the Fermi energy(40 MeV per nucleon)up to the CERN Large Hadron Collider energies(TeV).With further improvement in the nmuclear mean-field potential term,the collision term,and the cluster recognition term of the UrQMD model,the newly measured collective flow and nuclear stopping data of light charged particles by the FOPI Collaboration can be *** this article we highlight our recent results on the studies of the muclear EOS and the muclear symmetry energy with the UrQMD *** opportunities and challenges in the extraction of the nuclear EOS from transport models and HIC experiments are discussed.

关键词： muclear equation of state symmetry energy heavy ion collision transport model

Flat-type permanent magnet linear alternator:A suitable device for a free piston linear alternator

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 345-352页

作者： qing-feng li Jin XIAO Zhen HUANG MOE Key Laboratory for Power Machinery and Engineering Shanghai Jiao Tong University Shanghai 200240 China

We proposed the flat-type permanent magnet linear alternator (LA) for free piston linear alternators (FPLAs) instead of the tubular one. Using the finite element method (FEM), we compare these two kinds of LAs. The FEM result shows that the flat-type permanent magnet LA has higher efficiency and larger output specific power than the tubular one, therefore more suitable for FPLAs, and that the alternator design can be optimized with respect to the permanent magnet length as well as the air gap.

关键词： Free piston (FP) linear alternator (LA) Internal combustion engine (ICE) Finite element method (FEM)

Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes

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Chinese Chemical Letters 2007年第4期18卷 403-406页

作者： Bing Zhao Ya qing feng Yu Kun li School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and the different dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR, 1H NMR and MS. From their analysis data, it was found that compounds 8, 9, 11 adopted a cone conformation, while compound 10 existed as a mixture of conformations.

关键词： Pyrimidinylthiaalkoxycalixarenes Synthesis Characterization Conformation

Effects of sequential decay on collective flows and nuclear stopping power in heavy-ion collisions at intermediate energies

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Nuclear Science and Techniques 2023年第4期34卷 175-184页

作者： Kui Xiao Peng-Cheng li Yong-Jia Wang Fu-Hu liu qing-feng li State Key Laboratory of Quantum Optics and Quantum Optics Devices and Collaborative Innovation Center of Extreme Optics Institute of Theoretical PhysicsShanxi UniversityTaiyuan 030006China School of Science Huzhou UniversityHuzhou 313000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Institut für Theoretische Physik Goethe Universität FrankfurtFrankfurt am Main 60438Germany Institute of Modern Physics Chinese Academy of ScienceLanzhou 730000China

In this study, the rapidity distribution, collective flows, and nuclear stopping power in ^(197)Au+^(197)Au collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics(UrQMD) model with GEMINI++ code. The UrQMD model was adopted to simulate the dynamic evolution of heavy-ion collisions, whereas the GEMINI++ code was used to simulate the decay of primary fragments produced by UrQMD. The calculated results were compared with the INDRA and FOPI experimental data. It was found that the rapidity distribution, collective flows, and nuclear stopping power were affected to a certain extent by the decay of primary fragments, especially at lower beam energies. Furthermore, the experimental data of the collective flows and nuclear stopping power at the investigated beam energies were better reproduced when the sequential decay effect was included.

关键词： Heavy-ion collisions Sequential decay effect Collective flow Nuclear stopping power

Collective flow and nuclear stopping in heavy ion collisions in Fermi energy domain

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Nuclear Science and Techniques 2018年第12期29卷 54-61页

作者： Peng-Cheng li Yong-Jia Wang qing-feng li Hong-Fei Zhang School of Nuclear Science and Technology Lanzhou University School of Science Huzhou University Institute of Modern Physics Chinese Academy of Sciences

The effects of the in-medium nucleon-nucleon(NN) elastic cross section on the observables in heavy ion collisions in the Fermi energy domain are investigated within the framework of the ultrarelativistic quantum molecular dynamics model. The results simulated using medium correction factors of F=σ_(NN)^(in-medium)/σ_(NN)^(free)=0.2,0.3,0.5,and the density-and momentum-dependent factor obtained from the FU3 FP1 parametrization are compared with the FOPI and INDRA experimental data. It is found that the calculations using the correction factors F=0.2 and 0.5 reproduce the experimental data(i.e.,collective flow and nuclear stopping) at 40 and 150 MeV/nucleon, respectively. Calculations with the FU3 FP1 parametrization can best fit these experimental data. These conclusions can be confirmed in both^(197)Au+^(197)Au and^(129)Xe+^(120)Sn.

关键词：重离子碰撞原子精力流动集体修正因素动力学模型试验性

An explanation of the elliptic flow difference between proton and anti-proton from the UrQMD model with hadron potentials

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Science China(Physics,Mechanics & Astronomy) 2016年第3期59卷 60-65页

作者： qing feng li Yong Jia Wang Xiao Bao Wang Cai Wan Shen School of Science Huzhou University

The time evolution of both proton and anti-proton v2 flows from Au＋Au collisions at √SNN=7.7 GeV are examined by using both pure cascade and mean-field potential versions of the UrQMD model. Due to a stronger repulsion at the early stage introduced by the repulsive potentials and hence much less annihilation probabilities, anti-protons are frozen out earlier with smaller v2 values. Therefore, the experimental data of anti-proton v2 as well as the flow difference between proton and anti-proton can be reasonably described with the potential version of UrQMD.

关键词： elliptic flow difference UrQMD mean field potential annihilation process

Improving the efficiency of magnetic coupling energy transfer byetching fractal patterns in the shielding metals

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Frontiers of Information Technology & Electronic Engineering 2016年第1期17卷 74-82页

作者： qing-feng li Shao-bo CHE Wei-ming WANG Hong-wei HAO Lu-ming li School of Aerospace Tsinghua University Beijing 100084 China National Engineering Laboratory for Neuromodulation Beijing 100084 China Center of Epilepsy Beijing Institute for Brain Disorders Beijing 100084 China

Thin metal sheets are often located in the coupling paths of magnetic coupling energy transfer(MCET) systems. Eddy currents in the metals reduce the energy transfer efficiency and can even present safety risks. This paper describes the use of etched fractal patterns in the metals to suppress the eddy currents and improve the efficiency. Simulation and experimental results show that this approach is very effective. The fractal patterns should satisfy three features, namely, breaking the metal edge, etching in the high-intensity magnetic field region, and etching through the metal in the thickness direction. Different fractal patterns lead to different results. By altering the eddy current distribution, the fractal pattern slots reduce the eddy current losses when the metals show resistance effects and suppress the induced magnetic field in the metals when the metals show inductance effects. Fractal pattern slots in multilayer high conductivity metals(e.g., Cu) reduce the induced magnetic field intensity significantly. Furthermore, transfer power, transfer efficiency, receiving efficiency, and eddy current losses all increase with the increase of the number of etched layers. These results can benefit MCET by efficient energy transfer and safe use in metal shielded equipment.

关键词： Fractal pattern,Metal-layer-shield,Eddy current,Magnetic coupling energy transfer

Helium-3 production from Pb+Pb collisions at SPS energies with the UrQMD model and the traditional coalescence afterburner

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Science China(Physics,Mechanics & Astronomy) 2016年第3期59卷 66-69页

作者： qing feng li Yong Jia Wang Xiao Bao Wang Cai Wan Shen School of Science Huzhou University

A potential version of the UrQMD （UrQMD/M） transport model and a traditional coalescence model are combined to calculate the production of 3He fragments in central Pb＋Pb collisions at SPS energies 20-80 GeV/nucleon. It is found that the Lorentz transformation in the afterburner influences visibly the 3He yield and should be considered in calculations. The rapidity distribution of 3He multiplicities （including the concave shape） can be described well with UrQMD/M when it stops during tout=（100＋25） fm/c and the coalescence afterburner with one parameter set of （R0,P0）=（3.8 fm, 0.3 GeV/c） is taken into use afterwards.

关键词： rapidity distribution of Helium-3 UrQMD model coalescence model Lorentz transformation

Rapidity distribution of protons from the potential version of Ur QMD model and the traditional coalescence afterburner

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Science China(Physics,Mechanics & Astronomy) 2016年第2期59卷 36-39页

作者： qing feng li Yong Jia Wang Xiao Bao Wang Cai Wan Shen School of Science Huzhou University

Rapidity distributions of both E895 proton data at AGS energies and NA49 net proton data at SPS energies can be described reasonably well with a potential version of the Ur QMD in which mean-field potentials for both pre-formed hadrons and confined baryons are considered, with the help of a traditional coalescence afterburner in which one parameter set for both relative distance R_0 and relative momentum P_0,(3.8 fm, 0.3 Ge V/c), is used. Because of the large cancellation between the expansion in R_0 and the shrinkage in P_0 through the Lorentz transformation, the relativistic effect in clusters has little effect on the rapidity distribution of free(net) protons. Using a Woods-Saxon-like function instead of a pure logarithmic function as seen by FOPI collaboration at SIS energies, one can fit well both the data at SIS energies and the Ur QMD calculation results at AGS and SPS energies. Further, it is found that for central Au+Au or Pb+Pb collisions at top SIS, SPS and RHIC energies, the proton fractions in clusters are about33%, 10%, and 0.7%, respectively.

关键词： rapidity distribution of protons UrQMD model coalescence model Lorentz transformation

Effects of CeO_(2)pre-calcined at different temperatures on the performance of Pt/CeO_(2)-C electrocatalyst for methanol oxidation reaction

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International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1224-1232页

作者： Guo-qing li Pu-kang Wen Chen-qiang Gao Tian-yi Zhang Jun-yang Hu Yu-hao Zhang Shi-you Guan qing-feng li Bing li School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China School of Materials Science and Engineering East China University of Science and TechnologyShanghai 200237China Institute for Sustainable Energy College of SciencesShanghai UniversityShanghai 200237China Department of Energy Conversion and Storage Technical University of DenmarkLyngby 2800Denmark

Pt/CeO_(2)-C catalysts with CeO_(2)pre-calcined at 300-600 ℃were synthesized by combining hydrothermal calcination and wet *** effects of the pre-calcined CeO_(2)on the performance of Pt/CeO_(2)-C catalysts in methanol oxidation were *** Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 300-600 ℃showed an average particle size of 2.6-2.9 nm and exhibited better methanol elec-tro-oxidation catalytic activity than the commercial Pt/C *** specific,the Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 400 ℃dis-played the highest electrochemical surface area value of 68.14 m2·g−1 and If/Ib ratio(the ratio of the forward scanning peak current density(If)and the backward scanning peak current density(Ib))of 1.26,which are considerably larger than those(53.23 m2·g−1 and 0.79,respectively)of the commercial Pt/C catalyst,implying greatly enhanced CO tolerance.

关键词： direct methanol fuel cell platinum/cerium dioxide-carbon electrocatalyst methanol oxidation