检索结果-南通市图书馆

Science China(physics,Mechanics & Astronomy) 2009年第6期52卷 909-918页

作者： SHEN Fang1 & WU WangYi2 1 State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, beijing 100190, China 2 State Key Laboratory of Turbulence and Complex Systems & department of Mechanics and Engineering Science, peking university, beijing 100871, China 1. State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China 2. State Key Laboratory of Turbulence and Complex Systems & department of Mechanics and Engineering Science Peking University Beijing 100871 China

Basic function method is developed to treat the incompressible viscous flow. Artificial compressibility coefficient, the technique of flux splitting method and the combination of central and upwind schemes are applied to construct the basic function scheme of trigonometric function type for solving three-dimensional incompressible Navier-Stokes equations numerically. To prove the method, flows in finite-length-pipe are calculated, the velocity and pressure distribution of which solved by our method quite coincide with the exact solutions of Poiseuille flow except in the areas of entrance and exit. After the method is proved elementary, the hemodynamics in two-and three-dimensional aneurysms is researched numerically by using the basic function method of trigonometric function type and unstructured grids generation technique. The distributions of velocity, pressure and shear force in steady flow of aneurysms are calculated, and the influence of the shape of the aneurysms on the hemodynamics is studied.

关键词： basic function unstructured grid aneurysm viscous incompressible flow artificial compressibility flux splitting

在线全文

学校读者我要写书评

暂无评论

非耦合压缩Landau态

物理学报 1998年第5期47卷 718-723页

作者：田旭黄湘友武汉汽车工业大学基础课部北京大学物理系

引入Ｌａｎｄａｕ体系（带电粒子在垂直于均匀磁场的平面内的运动）的非耦合压缩态．利用这些压缩态可方便地描述带电粒子的圆周运动，且所得结果与规范的选择无关．

关键词：带电粒子均匀磁场 L体系非耦合压缩态

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, beijing 100029, China 2. department of atmospheric Sciences, Lanzhou university, Lanzhou 730000, China 3. Training Center for China Meteorological Administration, beijing 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

Existence of the solutions and the attractors for the large-scale atmospheric equations

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2006年第6期49卷 650-660页

作者： HUANG Haiyang1 & GUO Boling2 1. department of Mathematics, beijing Normal university, beijing 100875, China 2. Institute of Applied{4. and Computational Mathematics, beijing 100080, China 1. department of Mathematics Beijing Normal University Beijing 100875 China 2. Institute of Applied physics and Computational Mathematics Beijing 100080 China

In this paper, firstly, the proper function space is chosen, and the proper expression of the operators is introduced such that the complex large-scale atmospheric motion equations can be described by a simple and abstract equation, by which the definition of the weak solution of the atmospheric equations is made. Secondly, the existence of the weak solution for the atmospheric equations and the steady state equations is proved by using the Galerkin method. The existence of the non-empty global attractors for the atmospheric equations in the sense of the Chepyzhov-Vishik’s definition is obtained by constructing a trajectory attractor set of the atmospheric motion equations. The result obtained here is the foundation for studying the topological structure and the dynamical behavior of the atmosphere attractors. Moreover, the methods used here are also valid for studying the other atmospheric motion models.

关键词： atmosphere equations, weak solution, trajectory attractor, global attractor, equilibrium.

VARIATIONAL ITERATION SOLVING METHOD FOR SEA-AIR OSCILLATOR MODEL OF INTERDECADAL CLIMATE FLUCTUATIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2005年第3期 37-40页

作者： MO Jia-qi1, 2, LIN Yi-hua3, WANG Hui4.(1. department of Mathematics,Anhui Normal university,Wuhu 24.000,P. R. China 2. Division of Computational Science E-Institutes of Shanghai Universities at Shanghai Jiaotong university,Shanghai 20024.,P. R. China 3. Institute of atmospheric{4.,Chinese Academy of Sciences,beijing 100029,P. R. China 4. Chinese Academy of Meteorological Sciences,beijing 100081,P. R.China) department of Mathematics A nhui Normal UniversityWuhu 241000P. R. China Division of Computational Science E-Institutes of Shanghai Universities at Shanghai Jiaotong UniversityShanghai 200240P. R. China Institute of atmospheric physics Chinese Academy of SciencesBeijing 100029P. R. China Chinese Academy of Meteorological Sciences Beijing 100081P. R. China

atmospheric physics is a very complicated natural phenomenon and needs to simplify its basic models for the sea-air oscillator. And it is solved by using the approximate method. The variational iteration method is a simple and valid method. In this paper the coupled system for a sea-air oscillator model of interdecadal climate fluctuations is considered. Firstly, through introducing a set of functions, and computing the variations, the Lagrange multipliers are obtained. And then, the generalized expressions of variational iteration are constructed. Finally, through selecting appropriate initial iteration from the iteration expressions, the approximations of solution for the sea-air oscillator model are solved successively.

关键词： nonlinear variational iteration El Nio-Southern Oscillator model

Ultrafast Optical Kerr Effect of ConjugatedSilver Phenylacetylide Complex Oligomer

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 Chemical Letters 1999年第9期10卷 793-794页

作者： Yi Hui XU Li LIN Jia Gang LUO Boon K. TEO Zong Ju XIA Ying Hua ZOU Hut Ying CHEN (1department of Chemistry. university of Hinois at Chicago. Chicago. IL 60680. USA2department of physics. Mesoscopic physics Laboratory. peking university,beijing 1008713 Univ Illinois Dept Chem Chicago IL 60680 USA beijing Univ Dept Phys Mesoscop Phys Lab Beijing 100871 Peoples R China beijing Univ Dept Chem Inst Polymer Sci Beijing 100871 Peoples R China

Silver phenylacetylide oligomer was found to exhibit prominent third-order nonlinear optical property, with susceptibility chi((3)) of 2.4.10(-14. esu (10(-4. mol/L in 1:1 dimethyl sulfoxide/CHCl3 mixed solution) and second-order hyperpolarizability gamma of 5.18x10(-32) esu via heterodyned ultrafast optical Kerr effect measurement. It existed mainly as 1:1 complex oligomers and polymers as characterized by mass spectroscopy and elemental analysis etc.

关键词： silver phenylacetylide conjugated complex optical Kerr effect

A quasi-geostrophic wavelet-spectrum model for barotropic atmosphere and its numerical solution

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第11期 48-54页

作者： DAI Xingang 1,2*, WANG Ping 3 and CHOU Jifan 2 (1. Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of atmospheric physics, Chinese Academy of Sciences, START Regional Center for Temperate East Asia, beijing 100029, China 2. department of atmospheric Sciences, Lanzhou university, Lanzhou 730000, China 3. College of physics, peking university, beijing 100871, China) KeyLaboratoryofRegionalClimate-EnvironmentforTemperateEastAsia InstituteofAtmosphericPhysicsChineseAcademyofSciencesSTARTRegionalCenterforTemperateEastAsiaBeijing100029China Collegeofphysics PekingUniversity.Beijing100871China departmentofatmosphericSciences LanzhouUniversityLanzhou730000.China

A quasi-geostrophic wavelet-spectrum model of barotropic atmosphere has been constructed by wavelet-Galerkin method with the periodic orthogonal wavelet bases. In this study a wavelet grid-spectrum transform method is designed to decrease the tremendous computation of the nonlinear interaction term in the model, and a two-dimensional Helmholtz equation from the model in a wavelet spectrum form is derived, and a solution with high precision under the periodic boundary condition is obtained. The numerical investigation manifests that the wavelet-spectrum model (WSM) could keep on running for a long time under the forcing of heating and topography. Although its numerical solution is compatible with the grid model (GM), the WSM is of a higher precision and faster convergence rate than GM's. A stationary solution comes forth when the model is forced only by the surface heating, whereas a quasi-periodic oscillation with a period about 15 days appears as considering the topography in the model. The latter oscillation, to some extent, is very similar to the Rossby index cycle of atmosphere over middle and high latitudes.

关键词： plane barotropic atmosphere wavelet-spectrum model wavelet grid-spectrum transform.

Studies on wind environment around high buildings in urban areas

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第Z2期48卷 102-115页

作者： LIU Huizhi, JIANG Yujun, LIANG Bin, ZHU Fengrong, ZHANG Boyin & SANG Jianguo LAPC, Institute of atmospheric physics, Chinese Academy of Sciences, beijing 100029, China department of atmospheric Sciences, School of physics, peking university, beijing 1000871, China State Key Laboratory of Turbulence and Complex System, peking university, beijing 1000871, China LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China department of atmospheric Sciences School of Physics Peking University Beijing 1000871 China State Key Laboratory of Turbulence and Complex System Peking University Beijing 1000871 China

High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings.

关键词： high buildings in urban areas, wind environment, wind tunnel, numerical simulation.

Simulation Experiments of Land Surface Physical Processes and Ecological Effect over Different Underlying Surface

在线全文

学校读者我要写书评

暂无评论

地球科学进展 2004年第S1期19卷 15-20页

作者： LIU Shu-hua~(1,2), JIANG Hao-yu, HU Fei~2 LIU Hui-zhi~2 LIANG Fu-ming~1, WANG Jiang-hua~1(1. Group of Atmosphere Boundary Layer and turbulence, Ministry Laboratory of Storm and Drought Flood Damage, department of atmospheric Sciences the School of physics peking university,{4., China 2. State Key Laboratories of Atmosphere physics and Chemistry, Institute of atmospheric physics, Chinese Academy of Science, beijing 100029, China)

Based on the existing Land Surface Physical Process Models(Deardorff, Dickinson, LIU, Noilhan, Seller, ZHAO), a Comprehensive Land Surface Physical Process Model (CLSPPM) is developed by considering the different physical processes of the earth's surface-vegetation-atmosphere system more completely. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feas...

关键词： Comprehensive land surface Physical process model (CLSPPM) Simulation experiment Land surface physical process Ecological effect.

Perturbed solution of sea-air oscillator for the El Nino/ La Nina-Southern Oscillation mechanism

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2009年第3期28卷 1-4页

作者： ZHOU Xianchun LIN Yihua WANG Hui MO Jiaqi College of Electronic and Information Engineering Nanjing University of information Science and Technology Nanjing 210044 China Division of Computational Science E-Institutes of Shanghai Universities at SJTU Shanghai 200240 China State Key Laboratory of Numerical Modeling for atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China National Marine Environmental Forecastins Center Beijing 100081 China department of Mathematics Anhui Normal University Wuhu 241000 China

A class of coupled system of the E1 Nino/La Nina-Southern Oscillation （ENSO） mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic... 详细信息

关键词： nonlinear perturbation theory E1 Nino/La Nina-Southern Oscillation model