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The gravitational gradient tensor’s invariants and the related boundary conditions

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Science China Earth sciences 2010年第5期53卷 781-790页

作者： YU JinHai1,2,3 & ZHAO DongMing4 1 College of Earth Science, graduate university of chinese academy of sciences, Beijing 100049, China 2 Institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, China 3 State Key Laboratory of Astronautic Dynamics, Xi’an 710043, China 4 Zhengzhou Institute of Surveying and Mapping, Zhengzhou 450052, China College of Earth Science Graduate University of Chinese Academy of Sciences Beijing China Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China State Key Laboratory of Astronautic Dynamics Xi’an China Zhengzhou Institute of Surveying and Mapping Zhengzhou China

Here we report new approaches of recovering the Earth gravitational field from GOCE (Gravity field and steady-state Ocean Circulation Explorer) gradiometric data with the help of the gradient tensor’s invariants. Our results only depend on GOCE satellite’s position and gradiometry, in other words, they are completely independent of the satellite attitude. First, starting from the invariants, linearization models are established, which can be referred as the general boundary conditions on the satellite’s orbit. Then, the spherical approximation expressions for the models are derived, and the corresponding solving methods for them are discussed. Furthermore, considering effects of J2-term, the spherical approximation models are improved so that the accuracies of the boundary conditions can be theoretically raised to O ( J 2/2 T), which is approximately equivalent to O(T2). Finally, some arithmetic examples are constructed from EGM96 model based on the derived theories, and the computational results illustrate that the spherical models have accuracies of 10-7 and the order recovering the gravitational field can reach up to 200, and the models with regard to effect of J2-term have accuracies of 10-8 and the order can reach up to 280.

关键词： the Earth’s gravitational field gravitational gravidiometry tensor’s invariant

miRNAs modulate the drug response of tumor cells

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Science China(Life sciences) 2009年第9期52卷 797-801页

作者： WU XueMei1,3 & XIAO HuaSheng1,2 1 Center of Functional Genomics,Key Laboratory of System Biology,Shanghai Institutes for Biological sciences,chinese academy of sciences,Shanghai 200031,China 2 National Engineering Center for Biochip at Shanghai,Shanghai 201203,China 3 graduate university of chinese academy of sciences,Shanghai 200031,China Center of Functional Genomics Key Laboratory of System Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China

Chemotherapy is one of the major treatments of malignant carcinomas. However,its efficiency is affected by both intrinsic and acquired resistance to anticancer drugs. The cellular mechanisms of drug resistance include the overexpression of energy-dependent transporters that eject anticancer drugs from cells such as p-glycoprotein and multidrug resistance related protein (MRP),the mutation of drug targets,the activation of DNA repair pathways,the defects in cellular death pathways and so on. The genetic and epigenetic changes of these genes can lead to cancer drug resistance. Among these mechanisms,microRNAs (miRNAs) which are critical and essential for many important processes such as development,differentiation,and even carcinogenesis have been reported to regulate the chemosen-sitivity of tumor cells. In this paper we briefly review the relationship between miRNA and cancer drug resistance.

关键词： cancer drug resistance miRNAs

A revision of Elaeagnus L. (Elaeagnaceae) in China's mainland

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Journal of Systematics and Evolution 2010年第5期48卷 356-390页

作者： 1,2 Miao SUN 1Qi LIN 1(State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,chinese academy of sciences,Beijing 100093,China) 2(graduate university of chinese academy of sciences,Beijing 100049,China)

A revision of Elaeagnus *** China’s mainland is provided based on field observations and herbarium ***-two morphological characters are selected and coded,then the matrix is prepared following cluster *** characters and species delimitation are re-evaluated resulting in the recognition of 36 species,one subspecies and five varieties in China’s *** species names and three variety names are regarded as new *** information covers full synonyms,type information,description,taxonomic remarks,distribution range,occupied habitats,examined specimens,relevant illustrations,and references to selected published illustrations and reports.A key for whole species determination is *** lectotypification of Elaeagnus magna(Serv.)*** been designated.

关键词： cluster analysis Elaeagnaceae Elaeagnus relationships synonymy taxonomic revision.

Analysis of a kind of quantum cryptographic schemes based on secret sharing

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Science China(Physics,Mechanics & Astronomy) 2009年第9期52卷 1313-1316页

作者： ZHANG XingLan1 & JI DongYao2 1 College of Computer Science and Technology, Beijing university of Technology, Beijing 100124, China 2 State Key Laboratory of Information Security, graduate university of chinese academy of sciences, Beijing 100049, China College of Computer Science and Technology Beijing University of Technology Beijing China State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing China

Recently, Yang et al. proposed a kind of quantum cryptographic schemes based on secret sharing. The main idea is drawn from the case, where any n participants who share a secret K can co-operate as K does. This process can be applied to encryption, authentication, signature and so on. Unfortunately, since there is no identity authentication of the share's holder, these schemes inherit the limitation of secret sharing in practice. If some participants do not follow the protocol, the protocol would be a failure at last. Moreover, these schemes encounter another serious attack. Any two participants can co-operate to defeat the schemes by sending different shares to the parties unknown to the distributor of the secret K, such that these parties can execute the protocol as well. The attack proves that it is not enough for quantum cryptographic schemes that only the secret key is secure.

关键词： quantum identity authentication quantum secure direct communication quantum signature secret sharing

Inertial theory of the mean Hadley circulation under the condition of nonstatic equilibrium

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Science China Earth sciences 2006年第5期49卷 546-553页

作者： CHAO Jiping1 & LIU Fei2,3 1. National Marine Environmental Forecasting Center, Beijing 100081, China 2. Key Laboratory Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, chinese academy of sciences, Beijing 100029, China 3. graduate university of chinese academy of sciences, Beijing 100049, China National Marine Environmental Forecasting Center Key Laboratory Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences graduate university of chinese academy of sciences

Tropical atmosphere is divided into two layers, the layer near the ground is the planet boundary layer, where the motion is linear, if the radiation equilibrium temperature is given at the top of the boundary layer, the vertical motion there can be obtained. It is the non-viscous ideal atmos- pheric layer above the boundary one, where the motion is nonlinear. After getting the conservation laws of angular momentum, potential temperature and potential vortex, the inertial theory of the Hadley circulation driven by the vertical motion of the boundary layer is established, followed by sev- eral examples of its application.

关键词： Hadley circulation, inertial theory, conservation laws of angular momentum, potential temperature and potential vortex.

Empirical Analysis of Xinjiang's Bilateral Trade: Gravity Model Approach

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chinese Geographical Science 2008年第1期18卷 9-16页

作者： CHEN Xuegang YANG Zhaoping LIU Xuling Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China graduate university of the chinese academy of sciences Beijing 100049 China

Based on the basic trade gravity model and Xinjiang's practical situation, new explanatory variables (GDP, GDPpc and SCO) are introduced to build an extended trade gravity model fitting for Xinjiang's bilateral trade. From the empirical analysis of this model, it is proposed that those three variables affect the Xinjiang's bilateral trade posi- tively. Whereas, geographic distance is found to be a significant factor influencing Xinjiang’s bilateral trade negatively. Then, by the extended trade gravity model, this article analyzes the present trade situation between Xinjiang and its main trade partners quantitatively in 2004. The results indicate that Xinjiang cooperates with its most trade partners successfully in terms of present economic scale and developing level. Xinjiang has established successfully trade part- nership with Central Asia, Central Europe and Eastern Europe, Western Europe, East Asia and South Asia. However, the foreign trade development with West Asia is much slower. Finally, some suggestions on developing Xinjiang's for- eign trade are put forward.

关键词： trade gravity model extended trade gravity model bilateral trade Shanghai Cooperation Organization (SCO) Xinjiang

Electronic structure and magnetism of Fe-doped SiC nanotubes

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2,3,ZHANG FuChun3,ZHANG ZhiYong4,LU ShuYuan5 & YANG YanNing3 1 Xi’an Institute of Optics and Precision Mechanics,chinese academy of sciences,Xi’an 710068,China 2 graduate university of chinese academy of sciences,Beijing 100049,China 3 College of Physics and Electronic Information,Yan’an university,Yan’an 716000,China 4 Information Science and Technology Institution,Northwest university,Xi’an 710127,China 5 Department of Telecommunications,Xi’an Institute of Posts and Telecommunications,Xi’an 710121,China Xi"an Institute of Optics and Precision Mechanics Chinese Academy of Sciences graduate university of chinese academy of sciences College of Physics and Electronic Information Yan"an University Information Science and Technology Institution Northwest

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is 3.2 eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si 3p electron spins and Fe 3d electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired 3d electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

Power functions with low uniformity on odd characteristic finite fields

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Science China Mathematics 2010年第8期53卷 1931-1940页

作者： ZHA ZhengBang 1,3 & WANG XueLi 2 1 School of Mathematical sciences,Luoyang Normal university,Luoyang 471022,China 2 School of Mathematical sciences,South China Normal university,Guangzhou 510631,China 3 State Key Laboratory of Information Security,graduate university of chinese academy of sciences,Beijing 100049,China School of Mathematical sciences Luoyang Normal University School of Mathematical sciences South China Normal University State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences

In this paper,we give some new low differential uniformity of some power functions defined on finite fields with odd *** corollaries of the uniformity,we obtain two families of almost perfect nonlinear functions in GF... 详细信息

关键词： almost perfect nonlinear function differential uniform function finite field

Mapping the Farming-pastoral Ecotones in China

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Journal of Mountain Science 2009年第1期6卷 78-87页

作者： ZHANG Jian WEI Jie CHEN Quangon Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Tourism College Chongqing Normal University Chongqing 400047 China School of PastoralAgricultural Science and Technology Lanzhou University Lanzhou 730020 China graduate university of the chinese academy of sciences Beijing 100049 China

Conventional farming-pastoral ecotones methods of delineating were not quantitative and could not fully show their spatial distribution. The present paper attempts to develop quantitative methods for mapping farming-pastoral ecotones in China. Nine indicators, related to temperature, precipitation and altitude aspects, were selected to quantify ecological susceptibility of vegetation （crops and forage）. Methods of analytic hierarchy process （AHP） and expert score ranking combined with fuzzy set theory were applied to assign the weight for each indicator and to define the membership functions. The geographic information system （GIS） was used to manage the spatial database and conduct the spatial analysis. According to the spatial calculation of evaluation model integrated with GIS, the ecological susceptibility of vegetation （crops and forage） was mapped. Three different zones, pastoral area, farming-pastoral ecotones and farming area, were classified by spatial cluster analysis and the maximum likelihood classification for the numeric map of vegetation ecological susceptibility by GIS. This map was validated by the economic statistical result based on the ratio of the output value from animal husbandry in total output value of agriculture by the National Bureau of Statistics in China, indicating that the mapping of the farming-pastoral ecotones may be accepted.

关键词： AHP Farming-pastoral ecotone Fuzzyset theory GIS