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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 {3. 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 State Key Laboratory for space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China State Key Laboratory of Turbulence and Complex Systems & Department of Mechanics and Engineering science Peking University Beijing 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

A shortest path algorithm for moving objects in spatial network databases

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Progress in Natural science:Materials International 2008年第7期18卷 893-899页

作者： Xiaolan Yin a,b,*, Zhiming Ding c, Jing Li a a Technology center of Software Engineering, Institute of Software, chinese academy of {3., P.O. Box 8718, beijing 100080, china b Graduate University, chinese academy of {3.s, beijing 100049, china c Technology center of Basic Software, Institute of Software, chinese academy of {3.s, beijing 100080, china Technology center of Software Engineering Institute of Software Chinese Academy of Science P.O. Box 8718 Beijing 100080 China Graduate University Chinese Academy of Sciences Beijing 100049 China Technology center of Basic Software Institute of Software Chinese Academy of Sciences Beijing 100080 China

One of the most important kinds of queries in Spatial Network Databases (SNDB) to support location-based services (LBS) is the shortest path query. Given an object in a network, e.g. a location of a car on a road network, and a set of objects of interests, e.g. hotels, gas station, and car, the shortest path query returns the shortest path from the query object to interested objects. The studies of shortest path query have two kinds of ways, online processing and preprocessing. The studies of preprocessing suppose that the interest objects are static. This paper proposes a shortest path algorithm with a set of index structures to support the situation of moving objects. This algorithm can transform a dynamic problem to a static problem. In this paper we focus on road networks. However, our algorithms do not use any domain specific information, and therefore can be applied to any network. This algorithm’s complexity is O(klog2i), and traditional Dijkstra’s complexity is O((i + k)2).

关键词： Moving object Spatial network databases Shortest path index Shortest path

A new DNA algorithm to solve graph coloring problem

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Progress in Natural science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,Institute of Automation, chinese academy of sciences,{3., china 2. College of applied sciences, beijing University of Technology, beijing 100022, china 3. School of science, beijing Institute of Technology, beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of applied sciences Beijing University of Technology Beijing 100022 China School of science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

Bifurcations and Chaos in a Discrete Predator-prey System with Holling Type-IV Functional Response

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Acta Mathematicae Applicatae Sinica 2005年第1期21卷 157-176页

作者： Ji-cai Huang Department of applied Mathematics, College of science, china Agriculture University {3. of Mathematics and Systems science, chinese {3. of sciences, beijing 100080, china Department of applied Mathematics College of Science China Agriculture University academy of Mathematics and Systems science Chinese Academy of Sciences Beijing 100080 China

A discrete predator-prey system with Holling type-IV functional responseobtained by the Euler method is first investigated. The conditions of existence for foldbifurcation, flip bifurcation and Hopf bifurcation are derived by using the center manifold theoremand bifurcation theory. Furthermore, we give the condition for the occurrence of codimension-twobifurcation called the Bogdanov-Takens bifurcation for fixed points and present approximateexpressions for saddle-node, Hopf and homoclinic bifurcation sets near the Bogdanov-Takensbifurcation point. We also show the existence of degenerated fixed point with codimension three atleast. The numerical simulations, including bifurcation diagrams, phase portraits, and computationof maximum Lyapunov exponents, not only show the consistence with the theoretical analysis but alsoexhibit the rich and complex dynamical behaviors such as the attracting invariant circle,period-doubling bifurcation from period-2,3.4 orbits, interior crisis, intermittency mechanic, andsudden disappearance of chaotic dynamic.

关键词： predator-prey system bifurcations Bogdanov-Takens bifurcation chaos

MAGNETOSPHERIC PHYSICS

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空间科学学报 1998年第S1期18卷 27-38页

作者： LIU Zhen-xing(center for space science and {3. Researeh, The chinese academy of sciences,beijing 100080)PU Zu-yin (Department of Geophysics, Peking University)

Magnetospheric physics has been one of the most active areas in chinese space research in past two years. The major project "Energy Transport Processes in the Solar-Terrestrial System" (1993.1997) sponsored by the National Natural {3. Foundation in china (NSFC) has been successfully completed. Prestudies relevant to the key scientific engineering program "Meridian Chain at One Hundred Twenty Degree East Multi-Station and Multi-Instrument Observatory System" have started. A new key project "Study of Auroral Magnetospheric and Ionospheric Physics" (1997-1999) sponsored by the NSFC has begun. The space Active Experiment Program has been carrying on *** between chinese and international magnetospheric physicists have proceeded forward. More than 40 papers covering a variety of subjects in the magnetospheric physics were published in chinese and international academic journals. Most of these works were supported by the NSFC. This report provides a brief summary of aforementioned advances made in china in the past two years.

关键词： Magnetospheric physics Magnetopause Magnetic reconnection Substorm Magnetospheric modeling Magnetospheric waves and instabilities

Lunar surface dielectric constant,regolith thickness, and ~3.e abundance distributions retrieved from the microwave brightness temperatures of CE-1 Lunar Microwave Sounder

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science china Earth sciences 2010年第9期53卷 1365-1378页

作者： WANG ZhenZhan1, LI Yun1,2, JIANG JingShan1 & LI DiHui1 1 National Microwave Remote Sensing Laboratory, center for space science and applied research, chinese academy of {3.s, beijing 100190, china 2 Graduate University of chinese academy of {3.s, beijing 100049, china National Microwave Remote Sensing Laboratory Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Lunar regolith parameters, such as physical temperature, thickness and dielectric constant, are important in studying regolith features, distribution of lunar resources and evolution of the Moon. There had been no measurement obtained by lunar-orbit-borne microwave radiometer applied to evaluate the properties of lunar regolith before CE-1 Lunar Microwave Sounder (CELMS) being launched. CEMLS is the first passive microwave radiometer in the world to sound the surface of the Moon. The brightness temperatures (TB) sensed by CELMS include complicated information on the above geophysical parameters. In this paper, algorithms of retrieving dielectric constant, regolith thickness, and 3.e content from CELMS brightness temperatures are developed, and the results are compared with those from literature. The results show that the regolith thicknesses are mostly in the range of 4.0-6.0 m, and 43. of them are bigger than 5.0 m. The content of 3.e evaluated by retrieved regolith thickness is about 1.03.million tons.

关键词： CE-1 Lunar Microwave Sounder (CELMS) lunar regolith dielectric constant lunar regolith thickness 3.e retrieval

Algorithms for Markov stochastic models

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chinese science Bulletin 1999年第2期44卷 97-100页

作者： XU Guanghui (HSU Guang-Hui)Institute of applied Mathematics, chinese academy of {3.s, Asian-Pacific Operations research center Within CAS and APORS, beijing 100080, china Institute of applied Mathematics Chinese Academy of Sciences Asian-Pacific Operations Research Center Within CAS and APORS Beijing China

A survey of the main results of algorithmic studies of Markov processes and related stochastic models is shown. It consists of stationary solutions, transient solutions, first passage times, and multidimensional denum... 详细信息

关键词： Markov process stochastic model algorithm stationary solutions transient solutions first passage time uniform error.

Simulation studies of high-latitude magnetospheric boundary dynamics

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science china(Technological sciences) 2004年第4期47卷 421-435页

作者： PU Zuyin1, SHI Quanqi1,3. XIAO Chijie1, FU Suiyan1, ZHANG Hui1,2, ZONG Qiugang2 & LIU Zhenxing3.1. School of Earth and space sciences, Peking University, beijing 100871,{3. 2. center for space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA 3. center for space science and Application research, chinese academy of sciences,{13.,{3. School of Earth and space sciences Peking University Beijing China center for space science and Application {3. Chinese Academy of Sciences Beijing China center for space Physics Boston University Boston USA

Magnetic reconnection at the high-latitude magnetopause is studied using 2.5-dimensional Hall-MHD simulation. Concentric flow vortices and magnetic islands appear when both Hall effect and sheared flow are considered. Plasma mixing across the magnetopause occurs in the presence of the flow vortices. Reconnected structure generated in the vicinity of the subsolar point changes its geometry with increasing flow shear while moving to high latitudes. In the presence of flow shear, with the Hall-MHD reconnection a higher reconnection rate than with the traditional MHD is obtained. The out-of-plane components of flow and magnetic field produced by the Hall current are redistributed under the action of the flow shear, which makes the plasma transport across the boundaries more complicated. The simulation results provide some help in understanding the dynamic processes at the high latitude magnetopause.

关键词： magnetopause, entry layer, magnetic reconnection, vortex reconnection, Hall effect, flow shear.

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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science china(Physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： HUANG YongChang1,3.4, JIANG YunGuo1 & LI XinGuo2,3.1 Institute of Theoretical Physics, College of applied sciences, beijing University of Technology, beijing 100022, china 2 Institute of Modern Physics, chinese academy of sciences, Lanzhou 73.000, china 3.center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, chinese academy of sciences, Lanzhou 73.000, china 4 china center of Advanced science and Technology (World Laboratory), beijing 100080, china Institute of Theoretical Physics College of Applied Sciences Beijing University of Technology Beijing China center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou China china center of Advanced science and Technology (World Laboratory) Beijing China Institute of Modern Physics Chinese Academy of Sciences Lanzhou China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity

Study on Sulfide-melt Inclusions in Mantle Xenoliths of Xinchang, Zhejiang

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 5-9页

作者： Jiuhua Xu Xuelei Chu YulingXie Fenglei Bie Dayi Qian University of science and Technology beijing, beijing 100083.{3. china University of Geosciences, beijing 100083.{3. The research center of Mineral Resources Exploration, chinese academy University of science and Technology beijing Beijing 100083 China research center of Mineral Resources Exploration Chinese Academy of Sciences Beijing 100101 China Institute of Geology Chinese Academy of Sciences Beijing 100029 China china University of Geosciences Beijing 100083 China

In minerals of mantle xenoliths captured within Tertiary alkali-basalt from Xinchang, Zhejiang province, china, many sulfidemelt inclusions were found by the observation of polished thin section. Electron microprobe analysis has been applied to detect the components of sulfide-melt inclusions. The result shows that the sulfide phases of inclusions are mainly pentlandite, and secondarily pyrrho- tite, The molar ratio of Ni to Fe, r_Ni,/r_Fe, of mineral phases in sulfide inclusions is related to olivine contents in host mantle xenoliths. The r_Ni/r_Ni, of sulfides from Xinchang samples has a possitive correlation to r_(Fe+Ni),/r_S. The r_(Fe+Ni),/r_S, becomes higher with the increasing of r_Ni/r_Fe In single sulfide-melt inclusions, r_Ni,/r_Fe, r_(Fe+Ni),/r, and Ni contents increase from the center to edge, reflecting a result of different cooling speed in an inclusion. A comparison between the data from Hannuoba, West Eifel of Germany and Nograd-Gomor of east Europe suggests that the composition of the inclusions is different for each area, which indicated that a regional differentiation of sulfide in mantle fluids.

关键词： mantle xenolith sulfide-melt inclusion electron microprobe analysis, Xinchang