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Pre-LOI trajectory maneuvers of the CHANG'E-2 libration point mission

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Science China(information Sciences) 2012年第6期55卷 1249-1258页

作者： WU WeiRen 1,LIU Yong 2,3.LIU Lei 2,3.ZHOU JianLiang 3.TANG GeShi 2,3.& CHEN YongZhi 3.1 Chinese Lunar exploration and Space Project Center,beijing 10003.,China 2 Science and Technology on Aerospace Flight Dynamics Laboratory,beijing 10009{3.China 3.beijing Aerospace Control Center,beijing 10009{3.China Chinese Lunar exploration and Space Project Center Beijing China Science and Technology on Aerospace Flight Dynamics Laboratory Beijing China beijing Aerospace Control Center Beijing China

This paper addresses pre-LOI (before Lissajous orbit insertion) trajectory maneuvers for the libration point mission of CHANG'E-2,which is the first Chinese satellite to fly to the Sun-Earth L2 libration point and the first satellite ever to fly to the L2 point from lunar ***,a transfer trajectory for the mission is designed based on InterPlanetary Superhighway theory under the constraint of the remaining propellant,TT&C (telemetry,track and command) and sunlight *** effects of trajectory maneuver errors on the mission are also ***,based on the analysis results,the article investigates the trajectory maneuver schemes for the lunar escape and transfer trajectory maneuvers employing mathematical models and operational *** mission status based on our maneuver schemes is then presented,and the results of control operation and corresponding analysis are provided in ***,the future trajectory maneuver in the Lissajous orbit is *** to the analysis of the CHANG'E-2 TT&C data,the trajectory maneuver schemes proposed in the article work properly and efficiently.

关键词： CHANG’E-2 libration point trajectory maneuver escape trajectory transfer trajectory

Quasi-secure quantum dialogue using single photons

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Science China(Physics,Mechanics & Astronomy) 2007年第5期50卷 558-562页

作者： YANG YuGuang1,2 & WEN QiaoYan3. College of Computer Science and Technology, beijing university of Technology, beijing 100022, China 2 State Key Laboratory of {3. Security, Graduate university of the Chinese Academy of Sciences, beijing 10004., China 3.school of Science, beijing university of Posts and Telecommunications, beijing 100876, China College of Computer Science and Technology Beijing University of Technology Beijing China State Key Laboratory of information Security Graduate University of the Chinese Academy of Sciences Beijing China school of Science Beijing University of Posts and Telecommunications Beijing China

A quasi-secure quantum dialogue protocol using single photons was proposed. Different from the previous entanglement-based protocols, the present protocol uses batches of single photons which run back and forth between the two parties. A round run for each photon makes the two parties each obtain a classical bit of information. So the efficiency of information transmission can be increased. The present scheme is practical and well within the present-day technology.

关键词： quantum dialogue, single photon, quantum secure direct communication

Numerical study of the auroral particle transport in the polar upper atmosphere

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Science China(Technological Sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3.1 school of Electronic information, Wuhan university, Wuhan {3.0079, China 2 Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, Wuhan {3.0079, China 3.school of Earth and Space Sciences, Peking university, beijing 100871, China school of Electronic information Wuhan University Wuhan China Key Laboratory of Geospace Environment and Geodesy Ministry of Education of PRC Wuhan China school of Earth and Space Sciences Peking University Beijing China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

Attention and available long-term memory in an activation-based model

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Science China(Life Sciences) 2010年第6期53卷 743-752页

作者： LIU ZhaoMin1,GUO ChunYan2,3.& LUO Liang4.1 school of Sociology,China university of Political Science and Law,{3. 10224.,China 2 {3. Key Laboratory of Learning and Cognition,Department of Psychology,Capital Normal university,{3. 10004.,China 3.Key Laboratory of Mental Health,Chinese Academy of Sciences,{3. 100101,China 4.State Key Laboratory of Cognitive Neuroscience and Learning,{3. Normal university,{3. 100875,China school of Sociology China University of Political Science and Law Beijing China beijing Key Laboratory of Learning and Cognition Department of Psychology Capital Normal University Beijing China Key Laboratory of Mental Health Chinese Academy of Sciences Beijing China State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing China

The influence of attention on memorizing related items and on available long-term memory (ALTM) was explored,showing that N4.0 of no-memory items was more negative than that of the memory *** results of the category comparison task indicated that information processing under attention-driven in WM determined the availability of related long-term memory,i.e.,specific content,which was formerly concerned or ignored,yielding different indirect semantic priming *** indicate that the orientation of conceptual attention leads the related representations of LTM to diverse activation patterns,supporting the activation-based model.

关键词： activation-based model attention available long-term memory event-related potentials

A new theorem to synchronization of unified chaotic systems via adaptive control

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Journal of university of Science and Technology beijing 2003年第6期10卷 72-75页

作者： Lequan Min and Jianyi JingApplied Science school, university of Science and Technology beijing, beijing {4. China Univ Sci & Technol beijing Appl Sci Sch Beijing 100083 Peoples R China

Chaos synchronization has been applied in secure communication, chemicalreaction, biological systems, and information processing. A new theorem to synchronization ofunified chaotic systems via adaptive control is proposed. The constructive theorem provides thedesign scheme for adaptive controller such that a respond system can synchronize with respect to anuncertain drive system. One example for discontinuous chaotic system is proposed to illustrate theeffectiveness and feasibility.

关键词： uncertain chaotic system adaptive control synchronization Chua's circuit

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 4.1022,China 2 school of Mathematical Sciences,South China Normal university,Guangzhou 51063.,China 3.State Key Laboratory of {4. Security,Graduate university of Chinese Academy of Sciences,beijing 10004.,China school of Mathematical Sciences Luoyang Normal University Luoyang China State Key Laboratory of information Security Graduate University of Chinese Academy of Sciences Beijing China school of Mathematical Sciences South China Normal University Guangzhou China

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

Leakproof secret sharing protocols with applications to group identification scheme

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Science China(information Sciences) 2012年第5期55卷 1172-1185页

作者： TANG ChunMing 1,2 & GAO ShuHong 3.1 school of Mathematics and information Science,Guangzhou university,Guangzhou 510006,China 2 State Key Laboratory of information Security,Institute of Software Science,Chinese Academy of Sciences,{4. 10004.,China 3.Department of Mathematical Sciences,Clemson university,SC 2963.4}USA school of Mathematics and information Science Guangzhou University Guangzhou China State Key Laboratory of information Security Institute of Software Science Chinese Academy of Sciences Beijing China Department of Mathematical Sciences Clemson University Clemson USA

In a traditional (t,n)-threshold secret sharing scheme,t or more honest participants can reconstruct the secret *** the reconstruction process,the individual shares and the secret key K are revealed,hence K is shared once *** this paper,we firstly give the definition of leakproof secret sharing scheme which is composed of a distribution protocol and a proof protocol,then propose two leakproof secret sharing protocols,a computationally secure protocol and an information-theoretically secure *** our protocols,t or more participants can jointly prove that they hold the secret K by using a multi-prover zero-knowledge argument of *** a result,the secret K will be shared for as many times as ***,each participant can detect the dealer in the distribution protocol from cheating,and any verifier can prevent non-qualified set of participants in proof protocol from *** an example of the practical impact of our work we use our techniques to construct group identification schemes with zero-knowledge.

关键词： secret sharing leakproof secret sharing multi-prover zero-knowledge argument proof of knowl-edge group identification scheme

The band structures of BSb and B_xGa_(1-x)Sb alloys

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Science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 843-847页

作者： XIONG DePing1, ZHOU ShouLi2, WANG Qi3. LUO Li1, HUANG YongQing3.& REN XiaoMin3.1 school of Physics and Optoelectronic Engineering, Guangdong university of Technology, Guangzhou 510006, China 2 College of information Engineering, Zhejiang university of Technology, Hangzhou 3.003., China 3.Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education, {4. university of Posts and Telecommunications, {4. 100876, China school of Physics and Optoelectronic Engineering Guangdong University of Technology Guangzhou China College of information Engineering Zhejiang University of Technology Hangzhou China Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing China

The band structures of BSb and BxGa1-xSb alloys are studied using first-principles calculations in the generalized gradient approximation. By SQS-8 supercells to model a random alloy, the direct transition energy-gap (Γ15v- Γ1c) bowing of 3.0 eV is obtained for BxGa1-xSb alloys in x = 0-50%, in x = 0-11% the energy-gap is the band-gap and increases by 7 meV/%B with boron composition increasing; by SQS-16 supercells the bowing parameter is about 1.9 eV in x = 0-12.5%. The formation enthalpies of mixing, ΔH, are calculated for BxGa1-xAs and BxGa1-xSb alloys. A comparison of enthalpies indicates that BxGa1-xSb films with boron composition of 7% may be possible.

关键词： band-gap bowing parameter boride alloys

Retrieving crop leaf area index by assimilation of MODIS data into a crop growth model

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Science China Earth Sciences 2010年第5期53卷 721-730页

作者： WANG DongWei1,2,3. WANG JinDi1,2 & LIANG ShunLin4.1 State Key Laboratory of Remote Sensing Science, Jointly Sponsored by beijing Normal university and Institute of Remote Sensing Applications, CAS, beijing 100875, China 2 school of Geography, beijing Key Laboratory of Environmental Remote Sensing and Digital City, beijing Normal university, beijing 100875, China 3.Haihe River Water Conservancy Commission, Tianjin 3.0170, China 4.Department of Geography, university of Maryland, College Park, MD 2074., USA State Key Laboratory of Remote Sensing Science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications CAS Beijing China school of Geography Beijing Key Laboratory of Environmental Remote Sensing and Digital City Beijing Normal University Beijing China Haihe River Water Conservancy Commission Tianjin China Department of Geography University of Maryland College Park USA

Leaf area index (LAI) is an important parameter in monitoring crop growth. One of the methods for retrieving LAI from remotely sensed observations is through inversion of canopy reflectance models. Many model inversion methods fail to account for variable LAI values at different crop growth stages. In this research, we use the crop growth model to describe the LAI changes with crop growth, and consider a priori LAI values at different crop growth stages as constraint information. The key approach of this research is to assimilate multiple canopy reflectance values observed at different growth stages and a priori LAI values into a coupled crop growth and radiative transfer model sequentially using a variational data assimilation algorithm. Adjoint method is used to minimize the cost function. Any other information source can be easily incorporated into the inversion cost function. The validation results show that the time series of MODIS canopy reflectance can greatly reduce the uncertainty of the inverted LAI values. Compared with MODIS LAI product at Changping and Shunyi Counties of beijing, this method has significantly improved the estimated LAI temporal profile.

关键词： inversion leaf area index crop growth model time series MODIS