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Simulations for terrestrial planets formation

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Science China(Physics,Mechanics & Astronomy) 2009年第5期52卷 794-803页

作者： ZHANG Niu 1,2 &JI JiangHui 2,3 1Graduate university of chinese academy of sciences,beijing 100049,China 2Purple Mountain Observatory,chinese academy of sciences,Nanjing 210008,China 3 National Astronomical Observatories,chinese academy of sciences,beijing 100012,China Graduate university of chinese academy of sciences Beijing China Purple Mountain Observatory Chinese Academy of Sciences Nanjing China National Astronomical Observatories Chinese Academy of Sciences Beijing China

In this paper,the formation of terrestrial planets in the late stage of planetary formation is investigated using the two-planet *** that time,the protostar formed for about 3 Ma and the gas disk *** the model,the perturbations from Jupiter and Saturn are *** of the mass of outer planet,and the initial eccentricities and inclinations of embryos and planetesimals are also *** results show that,terrestrial planets are formed in 50 Ma,and the accretion rate is about 60%-80%.In each simulation,3-4 terrestrial planets are formed inside"Jupiter"with masses of 0.15 -3.6M⊕.In the 0.5-4 AU,when the eccentricities of planetesimals are excited,planetesimals are able to accrete material from wide radial *** plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this *** could also happen a few times between two major planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 10 8 *** one of our simulations,commensurability of the orbital periods of planets is very ***,a librating-circulating 3:2 configuration of mean motion resonance is found.

关键词： astrophysics exoplanet planetary formation n-body simulation

Twistor bundle theory and its application

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Science China Mathematics 2004年第4期47卷 605-616页

作者： PENG Chia-Kuei & TANG ZizhouDepartment of Mathematics, Graduate School of chinese academy of sciences, beijing 100039, China Department of Mathematical sciences, Tsinghua university, beijing 100084, China Department of Mathematics Graduate School of Chinese Academy of Sciences Beijing China Department of Mathematical sciences Tsinghua University Beijing China

Over an oriented even dimensional Riemannian manifold(M 2m ,ds2 ), in terms of the Levi-Civita connection form Ω and the canonical form Θ on the bundle of positive orthonormal frames, we give a detailed description of the twistor bundle Гm = SO(2m)/U(m)? J +(@#@ M,ds2 ) →M. The integrability on an almost complex structureJ compatible with the metric and the orientation, is shown to be equivalent to the fact that the corresponding cross section of the twistor bundle is holomorphic with respect toJ and the canonical almost complex structureJ 1 onJ +(M,ds2 ), by using moving frame theory. Moreover, for various metrics and a fixed orientation onM, a canonical bundle isomorphism is established. As a consequence, we generalize a celebrated theorem of LeBrun.

关键词： almost complex structure, integrability, twistor bundle.

Relationship between Environmental Pollution of Coal Mine and Spectral Characteristics of Nearby Plants

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Journal of university of Science and Technology beijing 2001年第1期8卷 10-14页

作者： Liqing Lei Institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, China Inst. of Geogr. Sci./Nat. Rsrc. Res. Chinese Academy of Sciences Beijing 100101 China

Remote sensing technology, as the most advanced method for collecting data, along with the common ways often used in the past on research of environmental science, was integrated to study the relationship between environmental pollution of coal mine and spectral characteristics of nearby plants. With compositive index and mean reflectivity at near infrared, a regression equation was established, and a conclusion was made that spectral reflectivity can be used to distinguish regions with different pollution degree. Through testing with real status of the research region, it is verified that this kind of integration and conclusion not only are helpful for human being in controlling the movement law of pollutants and the corresponding change of coal mine environmental quality but also bring a new way for the research of environment problems of coal mine.

关键词： remote sensing spectral characteristics reflectivity pollution index compositive index atmospheric pollution

Convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations

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Science China Mathematics 2006年第2期49卷 255-266页

作者： XIAO Ling, LI Fucai & WANG Shu academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, China Department of Mathematics, Nanjing university, Nanjing 210093, China College of Applied sciences, beijing university of Technology, beijing 100022, China academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Department of Mathematics Nanjing University Nanjing China College of Applied sciences Beijing University of Technology Beijing China

We establish the convergence of the Vlasov-Poisson-Fokker-Planck system to the incompressible Euler equations in this paper. The convergence is rigorously proved on the time interval where the smooth solution to the incompressible Euler equations exists. The proof relies on the compactness argument and the so-called relative-entropy method.

关键词： Vlasov-Poisson-Fokker-Planck system incompressible Euler equations relative-entropy method.

Line bundles on non-primary Hopf manifolds

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Science China Mathematics 2004年第4期47卷 538-551页

作者： LIU Weiming & ZHOU XiangyuInstitute of Mathematics, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, China Department of Mathematics, Zhejiang university, Hangzhou 310028, China Institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China Department of Mathematics Zhejiang University Hangzhou China

Let X be a Hopf manifolds with Abelian fundamental group, L any flat line bundle on X, we give a formula for computing explicitly the cohomology Hq(X, Ωp(L) using the method of group action and the generalized Douady... 详细信息

关键词： Hopf surface, cohomology, line bundle, sections.

Milestone of the meridian science──970th anniversary of the chinese Bronze Statue of Meridian

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chinese Science Bulletin 1998年第5期43卷 353-362页

作者： ZHANG Renji College of Life sciences, peking university, beijing 100871, China College of Life sciences Peking University Beijing 100871 China

For more than a thousand years, chinese people were aware of the transmitted sensations by the application of needles on the body surface. This practice is called acupuncture. Acupuncture had been recorded and transcribed in writings and in drawings, until finally the acupoints were inscribed onto a bronze statue. The bronze statue was called the Meridian Figure. Deeply embodied in the bronze statue is a tripartite confrontation-prism representation of the humans body. This concept was a great scientific achievement in ancient China. The author traces the history of Meridian science described in traditional chinese medical terms. Then he explores a clear analogy of the meridian pathway (MP) phenomenon. In a model system, by using a simple segmental in vertebrate, certain parallels can be demonstrated with the meridian concept. For example, the author demonstrated a clear correlation rule among the central mechano-sensory channels, and characteristics of positional discrimination in individual nerve cells from different receptive field inputs. The evidence suggests that the MP phenomenon is an objective neurobiological response. To clarify the research objective in this paper, the author suggests that the MP is a bi-directional pathway along which a positional message signal is transmitted. This phenomenon is evoked by physical stimulation, transmitted linearly across the human body segments, and is perceived by the brain. The MP consists of low resistance paths, is connected by the liquid media contained in the apposite membranous structure. At the cellular level, the regulation functions of MP must pass through along this low resistance path. Two aspects of the modern Meridian research are the functional regulation and the mechanism of intercellular liquid modulation at the nanometer level.

关键词： meridian pathway tripartite confrontation-prism coordinate position discriminative recognition apposite membranous structure.

Thermal analysis of the baffle structure of the Solar Space Telescope

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2,3 & WANG Sen1,3 1 National Astronomical Observatories,chinese academy of sciences,beijing 100012,China 2 Graduate university of chinese academy of sciences,beijing 100049,China 3 Key Laboratory of Solar Activity,National Astronomical Observatories of chinese academy of sciences,beijing 100012,China chinese academy of sciences National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***) Graduate university of chinese academy of sciences Beijing China (GRID:grid.458514.9) National Astronomical Observatories of chinese academy of sciences Key Laboratory of Solar Activity Beijing China (GRID:grid.450302.0) (ISNI:***) chinese academy of sciences National Astronomical Observatories Beijing China (GRID:grid.9227.e) (ISNI:***) National Astronomical Observatories of chinese academy of sciences Key Laboratory of Solar Activity Beijing China (GRID:grid.450302.0) (ISNI:***)

The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3' tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 200 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 200 mm,and the outer baffle of tilt angle 3' are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF

Research on applying physical chaos generator to spacecraft information security

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Science China(Technological sciences) 2009年第5期52卷 1463-1470页

作者： ZHAO HePing State Key Laboratory of Information Security,Graduate university of chinese academy of sciences,beijing 100049,China China academy of Space Technology,beijing 100094,China State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences China academy of Space Technology

The effectiveness of a short-length message extension method based on physical chaos generator was analyzed and the entropy of the extended message was calculated in this *** analysis demon-strated that with the mentioned method the entropy of short-length messages,which are repeatedly used in spacecraft data systems,is obviously increased,and the security of transmission is enhanced as *** paper also presented an improvement of the protocol for secret key agreement presented by *** and *** of depending on characteristics of communication channel,this method takes advantage of the random data produced by physical chaos generator to preset the initial parameters of the procedure on both sides of communication,so that the procedure and quantity of cipher key can be precisely *** method can be used to cipher key management of se-cure communication between long life-span spacecraft and ground system.

关键词： physical chaos generator spacecraft information security message extension cipher key management

Lactariolide,a New 14-Membered-Ring Compound from Lactarius Subvellereus

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chinese Chemical Letters 1997年第2期8卷 135-136页

作者： Jing ZHANG Xiao Zhang FENG(Institute of Materia Medica, chinese academy of Medical sciences and peking Union Medical College, beijing, 100050) Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Beijing 100050 China

Lactariolide (I), a new 14-membered-ring lactone was isolated from the fruit bodies of Lactarius subvellereus (Russulaceae), and its structure was elucidated as (R)-13-hydroxy-trans-9, 11-octadecadienoic acid lactone ... 详细信息

关键词： Cl Lactariolide,a New 14-Membered-Ring Compound from Lactarius Subvellereus