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用格子Boltzmann模型模拟垂直平板间的热对流

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物理学报 2004年第3期53卷 671-675页

作者：赵颖季仲贞冯涛中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室

引入一个新的能量分布函数 ,利用该能量分布函数与粒子速度分布函数耦合来求解一个热流场 .因而 ,这一能量分布函数与粒子速度分布函数和Boltzmann方程构成了一个新的格子Boltzmann模型 .这一模型满足质量、动量和能量守恒的准则 .用该... 详细信息

引入一个新的能量分布函数 ,利用该能量分布函数与粒子速度分布函数耦合来求解一个热流场 .因而 ,这一能量分布函数与粒子速度分布函数和Boltzmann方程构成了一个新的格子Boltzmann模型 .这一模型满足质量、动量和能量守恒的准则 .用该模型对垂直平板间的狭缝热对流进行了数值模拟 ,数值结果表明 ,在Prandtl数为 1,Grashof数在 1 3× 10 2 — 1× 10 6 之间时 ,流场将出现多个旋涡结构的流型 .

关键词：能量分布函数热对流 Boltzmann方程粒子速度分布函数能量守恒动量守恒质量守恒热力学

Symmetry of Y_5 Deformation and Two-Level Model

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chinese journal of nuclear physics 1994年第4期 337-343页

作者： Zhang Xi-zhen~(1,2) Dong Bao-guo~(1)(1 china institute of Atomic energy,P.O.Box 275(18),beijing 102413)(2 institute of Theoretical physics,chinese academy of Science,beijing 100080)

The symmetry of Y5μ-deformed fields are classified and the one-particlespectra in two-level model coupled by Y5μ fields are discussed.

关键词： Y5μ-deformed clusters Two-level model Single particle

Convergence for Imaginary Time Step evolution in the Fermi and Dirac seas

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 327-330页

作者： LI FangQiong1,ZHANG Ying2 & MENG Jie2,3,4 1Guizhou University for Nationalities,Guiyang 550025,china 2State Key Lab Nucl. Phys. & Tech.,School of physics,Peking University,beijing 100871,china 3School of physics and Nuclear energy Engineering,Beihang University,beijing 100191,china 4Department of physics,University of Stellenbosch,Stellenbosch,South Africa Guizhou University for Nationalities Guiyang China State Key Lab Nucl. Phys. & Tech. School of Physics Peking University Beijing China School of physics and Nuclear energy Engineering Beihang University Beijing China Department of physics University of Stellenbosch Stellenbosch South Africa

The convergence for the Imaginary Time Step (ITS) evolution with time step is investigated by performing the ITS evolution for the Schrdinger-like equation and the charge-conjugate Schrdinger-like equation deduced from Dirac equation for the single proton levels of 12C in both the Fermi and Dirac seas. For the guaranteed convergence of the ITS evolution to the "exact" results,the time step should be smaller than a "critical" time step Δtc for a given single-particle level. The "critical" time step Δtc is more sensitive to the quantum numbers |κ| than to the energy of the single-particle level. For the single-particle levels with the same κ,their "critical" time steps are in the same order. For the single-particle levels with similar energy,a relatively small (large) "critical" time step for larger (smaller) |κ| is needed. These conclusions can be used in the future self-consistent calculation to optimize the evolution procedure.

关键词： Dirac equation Schrdinger-like equation Imaginary Time Step method convergence

Damage from particle Impact for Structural Ceramics

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Journal of Materials Science & Technology 1994年第1期10卷 54-58页

作者： Zhongzhe JIN and Yiwang BAO(china Building Materials academy, beijing, 100024, china) china Building Materials Acad Beijing China

In this study, the relationship between the maximum impact force and velocity of partjcle has been derived on the basis of elastic theory and energy principle. Critical impact force and critical speed which cause initial damage is anaIVsed and its analytical expression is presented. The impact force for six dlfferent materials was measu red at the same condition to investigate the v8riation of impact pararneter with material properties. The authors provide a simple test method and experimental de vice to imitate the impact of moving particle, A series of experiments on ceramics and gIass were car ried out to study the dependence of residual strength on the impulse.

关键词： Damage from particle Impact for Structural Ceramics

THE EFFECT OF PION CONDENSATE IN ORDINARY FINITE NUCLEI

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Science china Mathematics 1989年第2期32卷 196-209页

作者：赵叔平刘宗廉马维兴冯正永 institute of Management Academia Sinica Beijing center of Theoretical physics CCAST (World Lab.) and Institute of High Energy Physics Academia Sinica Beijing Department of Modern physics University of Science and Technology of China Hefei

According to A. B. Migdal’s prediction that a pion condensate should exist in ordinaryfinite nuclei, a nucleon density modulation due to pion condensate has been obtained frompseudovector pion nucleon coupling and phenomenological effective repulsion *** on the nucleon density modulation, we study the effects of pion condensate in somenuclear phenomena, such as high energy particle nucleus scattering, X-ray energy spectrumof muonic atom and nuclear binding *** results strongly indicate that there aresome sufficient opportunities in these processes for pion condensate to manifest itself andthe condensate could help us to improve the agreement between theory and experiments formany processes.

关键词： pion condensate finite nuclei.

Ωw States in a Chiral Quark Model

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Communications in Theoretical physics 2007年第10期48卷 695-698页

作者： WANG Wen-Ling LIU Feng institute of particle physics,Huazhong Normal University,Wuhan 430079,chinaHUANG Fei CCAST (World Laboratory),P.O.Box 8730,beijing 100080,chinaZHANG Zong-Ye YU You-Wen institute of high energy physics,P.O.Box 918-4,beijing 100049,china WANG Wen-Ling LIU Feng institute of particle physics,Huazhong Normal University,Wuhan 430079,chinaHUANG Fei CCAST (World Laboratory),P.O.Box 8730,beijing 100080,chinaZHANG Zong-Ye YU You-Wen institute of high energy physics,P.O.Box 918-4,beijing 100049,china

The structures of Ωω states with spin-parity J=5/2~-,3/2~-,and 1/2~- are dynamically studied in boththe chiral SU(3)quark model and the extended chiral SU(3)quark model by solving a resonating group method(RGM)*** model parameters are taken from our previous work,which gave a satisfactory description of the energiesof the baryon ground states,the binding energy of the deuteron,the nucleon-nucleon(NN)scattering phase shifts,andthe hyperon-nucleon(YN)cross *** calculated results show that the Ωω state has an attractive interaction,and in the extended chiral SU(3) quark model such attraction can make for a Ωω quasi-bound state with spin-parityJ~ρ=3/2~- or 5/2~- and the binding energy of about several MeV.

关键词： Ωω quasi-bound states quark model chiral symmetry

Heating effect and biocompatibility of bacterial magnetosomes as potential materials used in magnetic fluid hyperthermia

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Progress in Natural Science:Materials International 2012年第1期22卷 31-39页

作者： Rui-ting Liu a,Jie Liu a,c,Jie-qiong Tong a,c,Tao Tang a,b,Wei-Chao Kong a,c,Xiao-wen Wang a,Ying Li b,Jin-tian Tang a a Key Laboratory of particle & Radiation Imaging(Tsinghua University),Ministry of Education,Department of Engineering physics,Tsinghua University,beijing 100084,china b State Key Laboratories for Agrobiotechnology and College of Biological sciences,china Agricultural University,beijing 100083,china c Department of Pharmaceutics,beijing University of chinese Medicine,beijing 100102,china Key Laboratory of particle & Radiation Imaging (Tsinghua University) Ministry of Education Department of Engineering Physics Tsinghua University Beijing 100084 China Department of Pharmaceutics Beijing University of Chinese Medicine Beijing 100102 China State Key Laboratories for Agrobiotechnology and College of Biological sciences China Agricultural University Beijing 100083 China

Magnetic fluid hyperthermia(MFH) promises to be a viable alternative in the treatment of localized cancerous *** treatment consists of introducing nanoparticles as energy absorbent agents in tumor tissue under an oscillating magnetic field,where nanoparticles dissipate energy in the form of heat,causing a localized rise in the temperature and tumor cell *** magnetic fluid under study is artificial magnetic *** work seeks to introduce the new natural biologic magnetic material bacterial magnetosomes(BMs) to be used in *** of magnetosomes and chemically synthesized magnetic nanoparticles(MNPs),such as morphology,magnetic properties and their heating effects under magnetic field were *** studies using human breast cancer cells MCF-7 indicated that cell viability could be significantly decreased by the heat derived from BMs and MNPs under alternative magnetic *** of BMs and MNPs was compared in terms of evaluating their acute toxicity in mice and their decomposition abilities in vitro,and it showed that magnetosomes exhibit a lower *** findings provide evidence for beneficial activities of magnetosomes in MFH and support the continued investigation of it to be applied in biomedicine.

关键词： Magnetosome Synthesized magnetic nanoparticles Magnetic fluid hyperthermia Properties Biocompatibility

小角x射线散射法研究甲基改性氧化硅凝胶的双分形结构

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物理学报 2003年第2期52卷 442-447页

作者：徐耀李志宏范文浩吴东孙予罕王俊董宝中中国科学院山西煤炭化学研究所煤转化国家重点实验室太原030001 中国科学院高能物理研究所同步辐射国家实验室北京100039

以正硅酸乙酯 [Si(OC2 H5) 4,TEOS]和甲基三乙氧基硅烷 [CH3Si(OC2 H5) 3,MTES]为前驱体 ,通过共水解法和两步法制备出两种不同的甲基改性氧化硅凝胶 ,在北京同步辐射光源 (BSRF)小角x射线散射 (SAXS)站测量了凝胶的散射强度 ,计算了凝... 详细信息

以正硅酸乙酯 [Si(OC2 H5) 4,TEOS]和甲基三乙氧基硅烷 [CH3Si(OC2 H5) 3,MTES]为前驱体 ,通过共水解法和两步法制备出两种不同的甲基改性氧化硅凝胶 ,在北京同步辐射光源 (BSRF)小角x射线散射 (SAXS)站测量了凝胶的散射强度 ,计算了凝胶的平均粒径、两相间比表面积等参数 ,在此基础上分析了凝胶的分形特征 ,发现存在两个尺度上的分形结构 ,分别对应于从SiO2 原生颗粒到一次团聚体和从一次团聚体到簇团两种尺度 .辅以透射电子显微镜 (TEM)观测 ,证实由两种方法获得的凝胶具有非常不同的微观结构 .实验证明 ,利用SAXS技术研究甲基改性凝胶的分形特征是获得凝胶微观结构的有力工具 .

关键词：甲基改性凝胶氧化硅小角x射线散射 SAXS 双分形结构散射强度

particle METHODS FOR COMPLEX FLOWS IN CHEMICAL ENGINEERING ——THE PSEUDO-particle APPROACH

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Particuology 2005年第Z1期 58-59页

作者： Wei GE and Jinghai LI Multi-Phase Reaction Laboratory, institute of Process Engineering, chinese academy of sciences, beijing 100080, P. R. china

The multi-scale structures of complex flows in chemical engineering have been great challenges to the design and scaling of such systems, and multi-scale modeling is the natural way in response. particle methods (PMs) are ideal constituents and powerful tools of multi-scale models, owing to their physical fidelity and computational simplicity. Especially, pseudo-particle modeling (PPM, Ge & Li, 1996; Ge & Li, 2003) is most suitable for molecular scale flow prediction and exploration of the origin of multi-scale structures; macro-scale PPM (MaPPM, Ge & Li, 2001) and similar models are advantageous for meso-scale simulations of flows with complex and dynamic discontinuity, while the lattice Boltzmann model is more competent for homogeneous media in complex geometries; and meso-scale methods such as dissipative particle dynamics are unique tools for complex fluids of uncertain properties or flows with strong thermal fluctuations. All these methods are favorable for seamless interconnection of models for different scales. However, as PMs are not originally designed as either tools for complexity or constituents of multi-scale models, further improvements are expected. PPM is proposed for microscopic simulation of particle-fluid systems as a combination of molecular dynamics (MD) and direct simulation Monte-Carlo (DSMC). The collision dynamics in PPM is identical to that of hard-sphere MD, so that mass, momentum and energy are conserved to machine accuracy. However, the collision detection procedure, which is most time-consuming and difficult to be parallelized for hard-sphere MD, has been greatly simplified to a procedure identical to that of soft-sphere MD. Actually, the physical model behind such a treatment is essentially different from MD and is more similar to DSMC, but an intrinsic difference is that in DSMC the collisions follow designed statistical rules that are reflection of the real physical processes only in very limited cases such as dilute gas. PPM is idea

关键词： multi-scale method particle method pseudo-particle modeling multi-phase flow