检索结果-南通市图书馆

Optimization of the imaginary time step evolution for the Dirac equation

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2011年第2期54卷 231-235页

作者： LI FangQiong1,ZHANG Ying2.LIANG HaoZhao2.3 & MENG Jie4.2.5 1Guizhou university for Nationalities,Guiyang 55002.,China 2.tate Key Lab Nuclear {2. & Technology,School of {2.,peking university,beijing 100871,China 3Institut de Physique Nucle’aire,IN2.3-CNRS and Universite’ Paris-Sud,F-914.6 Orsay Cedex,France 4.chool of {2. and Nuclear Energy Engineering,Beihang university,beijing 100191,China 5department of {2.,university of Stellenbosch,Stellenbosch,South Africa 1. Guizhou university for Nationalities Guiyang 550025 China2. State Key Lab Nuclear Physics & Technology School of Physics Peking University Beijing 100871 China3. Institut de Physique Nucléaire IN2P3-CNRS and Université Paris-Sud F-91406 Orsay Cedex France4. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China5. Department of Physics University of Stellenbosch Stellenbosch South Africa

Taking the single neutron levels of 12. in the Fermi sea as examples,the optimization of the imaginary time step(ITS) evolution with the box size and mesh size for the Dirac equation is *** the weakly bound states,in order to reproduce the exact single-particle energies and wave functions,a relatively large box size is *** long as the exact results can be reproduced,the ITS evolution with a smaller box size converges faster,while for both the weakly and deeply bound states,the ITS evolutions are less sensitive to the mesh ***,one can find a parabola relationship between the mesh size and the corresponding critical time step,i.e.,the largest time step to guarantee the convergence,which suggests that the ITS evolution with a larger mesh size allows larger critical time step,and thus can converge faster to the exact *** conclusions are very helpful for optimizing the evolution procedure in the future self-consistent calculations.

关键词： Dirac equation Schrdinger-like equation imaginary time step method convergence

Global analysis theory of climate system and its applications

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第10期48卷 1034-1039页

作者： LI Jianping1,2.& CHOU Jifan2.3 1. LASG, Institute of atmospheric physics, Chinese Academy of Sciences,{2. 10002., China 2. department of atmospheric Sciences, Lanzhou university, Lanzhou 730000, China 3. Training Center for China Meteorological Administration,{2. 100081, China department of atmospheric Sciences Lanzhou University Lanzhou 730000 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The idea and main theoretical results of the global analysis theory of climate system are briefly summarized in this paper. A theorem on the global behavior of climate system is given, i.e. there exists a global attractor in the dynamical equations of climate, any state of climate system will be evolved into the global attractor as time increases, indicating the nonlinear adjustment process of climate system to external forcing. The different effects of external forcing, dissipation and nonlinearity on the long-term behavior of solutions are pointed out, and some main applications of the global analysis theory are also introduced. Especially, three applications, the adjustment and evolution processes of climate, the principle of numerical model design and the optimally numerical integration, are discussed.

关键词：整体分析理论气侯体系应用不定性计算法则气侯科学数字模型

Preparation and Biological Distribution of New BATOs

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第1期8卷 81-82页

作者： Jing Tao WANG Xiang Yun WANG Yuan Fang LIU(department of Technical physics-{2., beijing 100871)(The current address is: Institute of Photographic Chemistry, Academia Sinica, Bejing 100101) beijing UNIV DEPT TECH PHYSBEIJING 100871PEOPLES R CHINA

Seven new boronic acid adducts of technetium(III) tris(dioxime) (BATO) were prepared and the biodistribution in mice of Tc-99m labelled BATOs were determined. The uptake of 1.62.1D in mice heart at 2.min after injection of (TcCl)-Tc-99m(MeCDO)(3)BMe indicates high myocardial extraction of this BATO. (TcCl)-Tc-99m(MeCDO)(3)BMe shows promise as a myocardial perfusion imaging agent.

关键词： DMG Preparation and Biological Distribution of New BATOs

On Hoava-Lifshitz cosmology

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2011年第5期35卷 429-435页

作者： CHEN Bin1) department of physics, and State Key Laboratory of Nuclear physics and Technology, peking university,{4., China department of physics and State Key Laboratory of Nuclear Physics and Technology Peking University

We give a brief overview of the Horava-Lifshitz-gravity theory, its modifications and its implications in cosmology. In particular, we discuss the various issues on the gravitational scalar mode, including its decoupling, its role as inflaton and its stability. Our analysis shows that the scalar mode could decouple naturally at λ = 1 due to the extra gauge symmetry. On the other hand, the fact that the scalar mode becomes ghost when 1/3 〈 λ 〈 1 is a real challenge to the theory. We try to overcome this problem by modifying the action such that the RG flow lies outside the problematic region. We discuss the cosmological implications of the theory.

关键词： Horava-Lifshitz-gravity cosmology ghost

Propagation of interplanetary shock excited ultra low frequency (ULF) waves in magnetosphere-ionosphere-atmosphere——Multi-spacecraft “Cluster” and ground-based magnetometer observations

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第9期53卷 2528-2534页

作者： WANG ChengRui1,2.ZONG QiuGang1,3 & WANG YongFu1 1 Institute of Space physics and Applied Technology,peking{2.,beijing {4.,China 2.Sate Key Laboratory of Space Weather,Chinese Academy of Sciences,beijing 100190,China 3 Center for atmospheric Research,600 Suffolk Street,university of Massachusetts Lowell,MA 01854.USA 1. Institute of Space physics and Applied Technology Peking University Beijing 100871 China2. Sate Key Laboratory of Space Weather Chinese Academy of Sciences Beijing 100190 China3. Center for Atmospheric Research University of Massachusetts 600 Suffolk Street Lowell MA 01854 USA

The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward *** paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF *** a comparison with recent observations,we found that: in the event during November 7,2.04.that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar *** with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic *** result reveals that the ULF wave is in contact with the ground geomagnetic *** ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic *** this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different *** on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process

关键词： ultra low frequency (ULF) wave magnetic storm ionosphere IRI model interplanetary shock

Simulation of nuclei morphologies for binary alloy

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2010年第11期53卷 2927-2936页

作者： LI DaMing1, & ZHANG PingWen2.1department of Mathematics, Shanghai Jiaotong university, Shanghai 2.02.2., China 2.ey Lab of Mathematics and Applied Mathematics, Center for Applied {2. and Technology and School of Mathematical Sciences, peking university,{{2., China 1. department of Mathematics Shanghai Jiaotong University Shanghai 200240 China2. Key Lab of Mathematics and Applied Mathematics Center for Applied Physics and Technology and School of Mathematical Sciences Peking University Beijing 100871 China

We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

关键词： nucleation crystal morphology string method

Supersymmetric WKB Approximation of Anharmonic Potential V(γ)=aγ~2.bγ-4.cγ-6

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2006年第7期46卷 37-38页

作者： QIAN Shang-Wu,~1 MIAO Chun-Hui,~1 and GU Zhi-Yu~2.~1physics department,{2., beijing 100871, China ~2.0} department, Capital Normal university, beijing 100037, China

This article uses the supersymmetric WKB approximation to obtain the approximate energy levels and wave functions of the anharmonic potential V(r) = ar~2.br+crin order to tesify the correctness between [Phys. Lett. A ... 详细信息

关键词： supersymmetric WKB approximation energy level wave function

Chapman-Enskog Expansion and Transport Coefficients for the NJL Model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese journal of nuclear physics 1995年第4期 283-288页

作者： Guo Hua, department of physics,{2., beijing 100871

The transport equation for the Nambu-Jona-Lasinio (NJL) model isderived phenomenologically. The finite-temperature effective mass for the quarkis analysed, By means of the Chapman-Enskog method and hydrodynamic ap-proach the different transport coefficients for the NJL plasma are calculated tothe first order in the relaxation time.

关键词： NJL model Chapman-Enskog expansion Transport coefficients

FURTHER EVIDENCE FOR FA CENTERS IN BaFCL:Eu^(2.) CRYSTAL

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1993年第9期4卷 817-820页

作者： Wei CHEN department of Materials physics,{2. university of Science and Technology,{2. 100083Mian Zeng SU department of Chemistry,peking university,{2. 100871

The formation of color centers in BaFCl:Eu^(2.) crystal is studied in more de- tail and further evidence for FA centers in BaFCl:Eu^(2.)is *** creation of color centers in BaFCl:Eu^(2.)may be devided into three *** long time X-irradiation be- yond stage 1,the concentration of FA centers depends linearly on the nth(n=1,2.or 3) power of F center *** under short time X-irradiation within stage 1,the concentration dependence of FA centers on F center is *** centers are easier to create than complex *** mechanisms for color centers formation in BaFCl:Eu^(2.) are also proposed and discussed.

关键词： FA FURTHER EVIDENCE FOR FA CENTERS IN BaFCL CRYSTAL