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Sea level variations in the South china Sea inferred from satellite gravity,altimetry,and oceanographic data

science china Earth {2. 2012年第10期55卷 1696-1701页

作者： FENG Wei 1,2.ZHONG Min 1,3 & XU HouZe 1,3 1 state key Laboratory of Geodesy and Earth’s Dynamics,{2. of Geodesy and Geophysics,chinese academy of sciences,Wuhan 430077,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 3 {2. of Geophysics,Huazhong University of science and Technology,Wuhan 430074,china state key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China Graduate University of chinese academy of sciences Beijing China institute of Geophysics Huazhong University of Science and Technology Wuhan China

Sea level variations(SLVs) can be divided into two major components:the steric SLV and the mass-induced *** two components of SLV in the South china Sea(SCS) are studied by using satellite altimetry,GRACE(Gravity Recovery and Climate Experiment) satellite gravity,and oceanographic data on annual and inter-annual *** the annual timescale,the geographic distribution of mass-induced SLV's amplitude jointly estimated from altimetry and the ECCO(Estimation of the Circulation and Climate of the Ocean) model agrees very well with that from *** observes obvious seasonal mass-induced SLV in the SCS with annual amplitude of 2.7±0.4 cm,which is consistent with the annual amplitude of 2.7±0.3 cm estimated from the steric-corrected *** the inter-annual timescales,the mean SLV in the SCS shows a large oscillation,which is mainly caused by the steric *** trend of mean SLV inferred from altimetry in the SCS is 5.5±0.7 mm/yr for the period of 1993-2.09,which is significantly higher than the global sea level rise rate of 3.3±0.4 mm/yr in the same *** is no obvious trend signal in the mass-induced SLV detected from GRACE that indicates the water exchange between the SCS and its adjacent seas and land is in balance within the study period.

关键词： altimetry GRACE ECCO the South china Sea sea level variation

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Numerical study of successive CMEs during November 4―5, 1998

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science china(Technological {2.) 2008年第10期51卷 1600-1610页

作者： ZHOU YuFen & FENG XueShang SIGMA Weather Group, state key Laboratory for Space Weather, Center for Space {2. and Applied Research, chinese academy of sciences, beijing 100190, china SIGMA Weather Group State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

We present the solar-terrestrial transit process of three successive coronal mass ejections (CMEs) of November 4―5, 1998 originating from active region 8375 by using a time-dependent three-dimensional magnetohydrodynamics (MHD) simula-tion. These CMEs interacted with each other while they were propagating in inter-planetary space and finally formed a "complex ejecta". A newly developed SIP-CESE MHD model was applied to solve MHD equations numerically. The quiet solar wind was started from Parker-like 1D solar wind solution and the magnetic field map was calculated from the solar photospheric magnetic field data. In our simulation, the ejections were initiated using pulse in the real active region 8375. The interplanetary disturbance parameters, such as speed, direction and angular size of the expanding CME, were determined from the SOHO/LASCO data with the cone-model. We discussed the three-dimensional aspects of the propagation, in-teraction and merging of the three ejections. The simulated interplanetary shocks were compared with the nearby-Earth measurement. The results showed that our simulation could reproduce and explain some of the general features observed by satellite for the "complex ejecta".

关键词： complex ejecta three-dimensional MHD simulation SIP-CESE MHD model

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New insights into the species problem

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science china(Life {2.) 2010年第8期53卷 964-972页

作者： YANG Yong1 & ZHOU ZheKun2.1state key Laboratory of Systematic and Evolutionary Botany, {2. of Botany, chinese academy of sciences, beijing 100093, china 2.1} Laboratory of Biodiversity and Biogeography, Kunming {2. of Botany, chinese academy of sciences, Kunming 6502.4, china state key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing China key Laboratory of Biodiversity and Biogeography Kunming Institute of Botany Chinese Academy of Sciences Kunming China

Historical opinions of the "species problem" are briefly reviewed, and four salient stages are recognized according to origin of species concepts. We propose that species is the unit preserving superior gene assembly and is maintained by specific mechanisms. Based on characteristics of plant evolution, we assume that understanding plant species may include three stages, i.e. morphological recognition stage, multidisciplinary verification stage, and illuminating mechanisms preserving superior gene assembly.

关键词： species concept plant evolution phylogeny

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A Group-Oriented (t,n) Threshold Signature Scheme with Traceable Signers

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Wuhan University Journal of Natural sciences 2008年第6期13卷 680-684页

作者： TAN Zuowen1,2.1. School of Information Technology, Jiangxi University of Finance and Economics, Nanchang 330013, Jiangxi, china 2. state {2. Laboratory of Information Security/institute of software, chinese academy of sciences, beijing 100190, china School of Information Technology Jiangxi University of Finance and Economics Nanchang China state key Laboratory of Information Security/{2. Chinese Academy of Sciences Beijing China

A group-oriented （t, n） threshold signature scheme employs the cryptographic techniques of secret share, allows any subset of t players out of n players to sign message on behalf of the group and disallows the creation of a valid signature if fewer than t players take part in the signature protocol. In this paper, we proposed a new group-oriented （t, n） threshold signature schemes with traceable signers based on Schnorr signature. The proposed scheme is proved traceable, robust and unforgeable against the ＂static＂ adversary with the discrete logarithm assumption in the random oracle model and existence of broadcast channel. The proofs of the strongest security （existential unforgeability against adaptively chosen message attacks under the discrete logarithm assumption） are provided in the random oracle model.

关键词： threshold signature random oracle model robustness

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

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science china Earth {2. 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, {2. 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 2.0, and the models with regard to effect of J2.term have accuracies of 10-8 and the order can reach up to 2.0.

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

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The biomarkers of 2.6,10,15, 19-pentamethylicosenes and their carbon isotopic composition in the sediments from the Gulf of Mexico

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chinese science Bulletin 2006年第14期51卷 1736-1740页

作者： SONG Zhiguang1,2.& WANG Cuiping1,31. state key Laboratory of Organic Geochemistry, Guangzhou {2. of Geochemistry, chinese academy of sciences, Guangzhou 510640, china 2. Guangzhou Research Center of Gas Hydrate, chinese academy of sciences, Guangzhou 510640, china 3. Graduate School of chinese academy of sciences, beijing 100039, china state key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Guangzhou Research Center of Gas Hydrate Chinese Academy of Sciences Guangzhou China Graduate School of chinese academy of sciences Beijing China

A group of 2.6,10,15,19-pentamethyli- cosenes (PMIΔ) containing 1―5 unsaturated double bonds has been identified in the sea floor sediments from the Gulf of Mexico at the Green Canyon 2.8 *** PMIΔ compounds are distributed between nC2. and nC2. on the mass chromatogram of aliphatic fraction. Their δ 13C values are very much depleted in 13C and in the range of ?86.7‰ to ?115.5‰, whereas the δ 13C values of companion n-alkanes range from ?2..4‰ to ?34.6‰. These unsaturated PMIΔ com-pounds are typical biomarkers derived from the an-aerobic oxidation of methane mediated by meth-ane-oxidizing archaeal bacteria and indicative of the gas seeps or even the occurrence of gas hydrates in the deep sea sediments.

关键词：生物标志墨西哥湾沉积物 PMIA 天然气水化物

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Detection of the urban heat island in beijing using HJ-1B satellite imagery

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science china Earth {2. 2010年第S1期53卷 67-73页

作者： YANG Jun1,GONG Peng2.ZHOU JinXing3,HUANG HuaBing2.& WANG Lei2.1 key Laboratory of Silviculture and Conservation,Ministry of Education,beijing Forestry University,beijing 100083,china 2.state key Laboratory of Remote Sensing science,jointly sponsored by the institute of Remote Sensing Applications,chinese academy of sciences and beijing Normal University,beijing 100101,china 3 institute of Desertification Studies,chinese academy of Forestry,beijing 100091 china key Laboratory of Silviculture and Conservation Ministry of Education Beijing Forestry University Beijing China state key Laboratory of Remote Sensing {2. jointly sponsored by the Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Beijing China institute of Desertification Studies Chinese Academy of Forestry Beijing China

Satellite images are used extensively in studying the urban heat island(UHI) *** evaluated the suitability of thermal infrared(TIR) data from the HJ-1B satellite for detecting UHI using a case study in *** modified algorithms for retrieving the land surface temperature(LST) from HJ-1B data were *** results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST *** spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS *** the two algorithms,the mono-window algorithm performed better but further tests are *** more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in china and neighboring countries.

关键词： surface temperature NDVI mono-window algorithm single-channel algorithm

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An ID-based authenticated dynamic group key agreement with optimal round

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science china(Information {2.) 2012年第11期55卷 2542-2554页

作者： TENG JiKai1,2.WU ChuanKun1 & TANG ChunMing3 1state key Laboratory of Information Security,{2. of chinese academy of sciences,beijing 100090,china 2.raduate University of chinese academy of sciences,beijing 100049,china 3Faculty of Mathematic and Information science,Guangzhou University,Guangzhou 510006,china state key Laboratory of Information Security Institute of Software of Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Faculty of Mathematic and Information science Guangzhou University Guangzhou China

Group key agreement protocols are crucial for achieving secure group *** are designed to provide a set of users with a shared secret key to achieve cryptographic goal over a public *** group membership changes,the session key should be refreshed efficiently and *** previous group key agreement protocols need at least two rounds to establish or refresh session *** this paper,a dynamic authenticated group key agreement(DAGKA) protocol based on identity-based cryptography is *** making use of the members' values stored in previous sessions,our Join and Leave algorithms reduce the computation and communication costs of *** the proposed protocol,Setup and Join algorithms need one *** session key can be refreshed without message exchange among remaining users in Leave algorithm,which makes the protocol more *** security is proved under decisional bilinear Diffie-Hellman(DBDH) assumption in random oracle model.

关键词： identity-based cryptography dynamic group key agreement provably secure admissible pairing

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Interaction between electromagnetic waves and energetic particles by a realistic density model

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science china(Technological {2.) 2010年第9期53卷 2552-2557页

作者： HE YiHua1,2.CHEN LiangXu1,XIAO FuLiang1 & YANG Chang1 1 School of Physics and Electronic sciences,Changsha University of science and Technology,Changsha 410004,{2. 2.state key Laboratory of Space Weather,chinese academy of sciences,beijing 100190,{2. School of Physics and Electronic sciences Changsha University of Science and Technology Changsha China state key Laboratory of Space Weather Chinese Academy of Sciences Beijing China

Using a realistic density model,we present a first study on the interactions between electromagnetic waves and energetic particles in the inner *** calculations show that as the latitude λ increases,the number density ne increases,and resonant frequency range moves to lower pitch *** L-mode/electron and L-mode/proton interactions,the pitch angle diffusion dominates over the momentum *** indicates that L-mode waves are primarily responsible for pitch angle *** R-mode/electron interaction,the momentum diffusion is found to be comparable to the pitch angle diffusion,implying that R-mode waves can play an important role in both pitch angle scattering and stochastic acceleration of *** R-mode/proton interaction,diffusion coefficients locate primarily below pitch angle 60° and increase as kinetic energy increases,suggesting that R-mode waves have potential for pitch angle scattering of highly energetic (~1 MeV) protons but cannot efficiently accelerate protons.

关键词： wave-particle interaction energetic particles resonant frequency pitch angle and momentum diffusion density model

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ON THE OBSERVABILITY AND DETECTABILITY OF LINEAR STOCHASTIC SYSTEMS WITH MARKOV JUMPS AND MULTIPLICATIVE NOISE

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Journal of Systems science & Complexity 2010年第1期23卷 102-115页

作者： Yuanhua NI Weihai ZHANG Haitao FANG key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China. College of Information and Electrical Engineering Shandong University of Science and Technology Qingdao China.

This paper presents the notions of exact observability and exact detectability for Markov jump linear stochastic systems of Ito type with multiplieative noise （for short, MJLSS）. Stochastic Popov-Belevith-Hautus （PBH） Criterions for exact observability and exact detectability are respectively obtained. As an application, stochastic H2.H∞ control for such MJLSS is discussed under exact detectability.

关键词： Exact detectability exact observability Markov jump systems multiplicative noise PBH Criterion stochastic H2.H∞ control.

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