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Symmetry energy dependence of the pygmy and giant dipole resonances in an isospin dependent quantum molecular dynamics model

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Nuclear Science and Techniques 2013年第3期24卷 55-60页

作者： TAO Cheng MA Yugang ZHANG Guoqiang CAO Xiguang fang deqing WANG Hongwei Shanghai Institute of Applied Physics Chinese Academy of SciencesJiading Campus University of Chinese Academy of Sciences

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.

关键词：量子分子动力学模型巨偶极共振同位旋相关对称能能源侏儒 IQMD 峰值能量

Initial fluctuation effect on elliptic flow in Au+Au collision at 1 GeV/A

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Nuclear Science and Techniques 2013年第3期24卷 50-54页

作者： WANG Jia MA Yugang ZHANG Guoqiang fang deqing HAN Lixin SHEN Wenqing Shanghai Institute of Applied Physics Chinese Academy of SciencesJiading campus University of Chinese Academy of Sciences

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.

关键词：波动影响椭圆流伏特电子量子分子动力学碰撞流量计算空间实验

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中子皮结构及其在核反应中的效应

核技术 2023年第8期46卷 148-154页

作者：方德清教育部核物理与离子束应用重点实验室复旦大学现代物理研究所上海200433

中子皮是不稳定原子核中存在的一种奇特结构,在核反应过程中会产生各种效应。不同理论模型研究发现,中子皮厚度会影响核-核碰撞中的中子擦去截面、轻粒子产额比、重碎片产额比、光子产生截面等物理量,也与原子核的集团结构、表面宽度、... 详细信息

中子皮是不稳定原子核中存在的一种奇特结构,在核反应过程中会产生各种效应。不同理论模型研究发现,中子皮厚度会影响核-核碰撞中的中子擦去截面、轻粒子产额比、重碎片产额比、光子产生截面等物理量,也与原子核的集团结构、表面宽度、温度等存在密切关系。在高能重离子碰撞中研究发现,中子皮同样存在明确的效应。实验上,基于放射性核束装置可以产生具有中子皮结构的不稳定核,通过测量其与稳定核发生反应后与中子皮敏感的观测量,能提取或确定中子皮厚度。结合核理论模型,可以进一步约束非对称核物质的状态方程及核天体的相关性质。

关键词：中子皮放射性核束非对称核物质的状态方程

Swimmer with submerged SiO_(2)/Al/LiNbO_(3) surface acoustic wave propulsion system

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Biomimetic Intelligence & Robotics 2024年第2期4卷 71-77页

作者： deqing Kong Ryo Tanimura fang Wang Kailiang Zhang Minoru Kuribayashi Kurosawa Manabu Aoyagi Department of Engineering Muroran Institute of TechnologyMuroran 050-8585Japan Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and EngineeringTianjin University of TechnologyTianjin 300384China School of Engineering Tokyo Institute of TechnologyYokohama 226-8501Japan

Acoustic propulsion system presents a novel underwater propulsion approach in small scale *** study introduces a submerged surface acoustic wave(SAW)propulsion system based on the SiO_(2)/Al/LiNbO_(3) *** 19.25 MHz,the SAW propulsion system is proposed and investigated by the propulsion force calculation,PIV measurements and propulsion measurements.3.3 mN propulsion force is measured at 27.6 V_(pp).To evaluate the miniature swimmer,the SAW propulsion systems with multiple frequencies are *** 2.2 W,the submerged SAW propulsion system at 38.45 MHz demonstrates 0.83 mN/mm^(2) propulsion *** 96.13 MHz and 24 V_(pp),the movements of miniature swimmer with a fully submerged SAW propulsion system are recorded and analyzed to a maximum of 177 mm/*** of miniaturization,high power density,and simple structure,the SAW propulsion system can be expected for some microrobot applications,such as underwater drone,pipelinerobotand intravascularrobot.

关键词： Acoustofluidics Surface acoustic wave Swimmer Underwater propulsion system

Origin of the finite nuclear spin and its effect in intermediate energy heavy ion collisions

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Nuclear Science and Techniques 2012年第1期23卷 61-64页

作者： ZHANG Guoqiang CAO Xiguang FU Yao MA Yugang CAI Xiangzou WANG Hongwei fang deqing CHEN Jingen GUO Wei Tian Wendong LIU Guihua Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

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 *** interesting multi-fragmentation phenomena related to the spin are *** also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC.

关键词：中能重离子碰撞核自旋起源激发能量空间探索影响参数反应体系断裂现象

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双质子发射实验研究进展

科学通报 2020年第35期65卷 4018-4026页

作者：方德清马余刚复旦大学现代物理研究所教育部核物理与离子束应用重点实验室上海200433

放射性是不稳定核的一个重要特性,比较常见的模式有α、β、γ衰变及裂变.双质子发射是质子滴线区原子核的一种奇异放射性,对研究极端丰质子核的结构、质量、质子对关联等有重要意义,是近年来放射性核束物理的重要前沿方向之一.本文简... 详细信息

放射性是不稳定核的一个重要特性,比较常见的模式有α、β、γ衰变及裂变.双质子发射是质子滴线区原子核的一种奇异放射性,对研究极端丰质子核的结构、质量、质子对关联等有重要意义,是近年来放射性核束物理的重要前沿方向之一.本文简要评述了双质子发射实验研究进展,介绍了几种常用的实验探测方法及鉴别双质子发射机制的研究方法.奇异放射性研究的困难在于滴线区不稳定核的产生.中国在建的HIAF装置有强流的优势,结合先进的探测技术与研究方法,将来有望在滴线区原子核的奇异放射性实验研究方向开展最前沿的工作.

关键词：丰质子核双质子发射在束衰变方法注入衰变方法光学读出时间投影室成像方法

Isospin and symmetry energy study in nuclear EOS

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Science China(Physics,Mechanics & Astronomy) 2011年第S1期54卷 141-148页

作者： TIAN WenDong1, MA YuGang1, CAI XiangZhou1, fang deqing1, WANG HongWei1 & WU HongLi1,2 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China 2 Graduate School of University of Science and Technology of China, Hefei 230026, China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai China Graduate School of University of Science and Technology of China Hefei China

This paper summarizes the isoscaling and isospin related studies in asymmetry nuclear reactions by different dynamic and sta tistical models. Isospin dependent quantum molecular dynamics model (IQMD) and lattice gas model (LGM) are used to study the isoscaling properties and isoscaling parameters dependence on incident energies, impact parameters, temperature and other parameters. In the LGM model, the signal of phase transition has been found in free neutron (proton) chemical potential dif ference Δμn or Δμp as a function of temperature, or in free neutron and proton chemical potential difference Δμn-Δμp. Density dependence of symmetry energy coefficient Csym(ρ/ρ0) is also studied in the frame of LGM, with the potential parameters which can reproduce the nuclear ground state property, soft density dependence of symmetry energy is deduced from the sim ulation results. Giant dipole resonance (GDR) induced by isospin asymmetry in entrance channel is also studied via IQMD model, and the dynamic dipole resonance shows isospin sensitivity on the isospin asymmetry of entrance channel and sym metry energy of the nuclear equation of state (EOS). GDR can also be regarded as a possible isospin sensitive signature.

关键词： nuclear EOS isospin isoscaling density giant dipole resonance

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碎裂反应和放射性核束的产生

物理学进展 2000年第4期20卷 335-355页

作者：方德清沈文庆中国科学院上海原子核研究所，上海 201800 宁波大学，宁波 315211

本文总结了中能重离子碰撞产生同位素分布的计算方法和模型 ,包括参数化公式 ,擦碎模型和统计擦碎模型。介绍了模型的物理基础和计算方法 ,并讨论了对擦碎模型和统计擦碎模型的修正。同时用统计擦碎模型探讨了碎裂反应产生的同位素分布... 详细信息

本文总结了中能重离子碰撞产生同位素分布的计算方法和模型 ,包括参数化公式 ,擦碎模型和统计擦碎模型。介绍了模型的物理基础和计算方法 ,并讨论了对擦碎模型和统计擦碎模型的修正。同时用统计擦碎模型探讨了碎裂反应产生的同位素分布的同位旋效应。然后介绍了放射性核束的产生方法 ,并对放射性束流物理的发展前景作了简要介绍。

关键词：碎裂反应放射性核束擦碎模型同位旋效应中能重离子炮弹碰撞同位素

中子皮厚度测量探针对核物质状态方程的依赖性

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原子核物理评论 2016年第1期33卷 8-12页

作者：孙小艳方德清马余刚临沂大学理学院山东临沂276000 中国科学院上海应用物理研究所上海201800

利用同位旋相关的量子分子动力学(IQMD)模型模拟了4He+208Pb的碰撞反应,发现中子-质子产额比(Rnp)与208Pb的中子皮(δnp)之间存在很好的线性关联,中子-质子产额比可以作为中子皮厚度测量的一个探针。选取IQMD模型中核物质状态方程的两... 详细信息

利用同位旋相关的量子分子动力学(IQMD)模型模拟了4He+208Pb的碰撞反应,发现中子-质子产额比(Rnp)与208Pb的中子皮(δnp)之间存在很好的线性关联,中子-质子产额比可以作为中子皮厚度测量的一个探针。选取IQMD模型中核物质状态方程的两套不同势参数进行模拟,通过对比发现,中子皮的厚度测量探针(中子-质子产额比)对核物质状态方程中选择软势和硬势非常敏感,相同反应条件下,软势比硬势计算所得的中子质子产额比要低。无论选择何种状态方程参数,中子质子产额比与中子皮之间都存在线性关联。

关键词：中子皮厚度量子分子动力学核物质状态方程