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Spatial heterogeneity of the driving forces of cropland change in china

Science china Earth {1. 2005年第12期48卷 2231-2240页

作者： LIU Xuhua1,2. WANG Jinfeng1, LIU Mingliang4,1 & MENG Bin1,2.3 1. Institute of Geographic sciences and Natural Resources Research, chinese {2. of sciences, beijing 100101, china 2. Graduate School of the chinese {2. of sciences, beijing 100039, china 3. College of Arts and sciences of beijing Union university, beijing 100083, china 4. School of Forestry and Wildlife sciences, Auburn university, Auburn, Alabama, AL36849, USA 1. Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Graduate School of the {1. academy of {2. 100039 Beijing China 3. School of Forestry and Wildlife sciences Auburn University Auburn AL36849 Alabama USA 4. College of Arts and sciences of {1. Union {2. 100083 Beijing China

By using digital satellite remote sensing data acquired in 1.87―1.89 and 1.99―2.00 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in{1.. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of{1., natural condition changes and geographical background were the main constraints and drivers, while in Eastern{1., social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in{1. recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

关键词： land use change, driving force, integrated classification, spatial statistics, cropland, china.

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Environmental characteristics of Mid-Holocene recorded by lacustrine sediments from Lake Daihai, north environment sensitive zone, china

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Science china Earth {1. 2006年第9期49卷 968-981页

作者： SUN Qianli1,2. ZHOU Jie1, SHEN Ji3, CHEN Peng1,2. WU Feng1,2.& XIE Xiuping1,2.1. State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, chinese academy of {2., Xi’an 710075, china 2. Graduate university of chinese academy of {2., beijing 100039, china 3. Nanjing Institute of Geography and Limnology, chinese academy of {2., Nanjing 2.0008, china 1. State Key Lab of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 2. Graduate {1. of chinese {2. of sciences Beijing 100039 China 3. Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China

Climate proxies, such as total organic carbon and nitrogen (TOC, TN), carbonate content (CaCO3), grain-size and pollen of the sediment core retrieved from enclosed Lake Daihai which lies in the north china environment sensitive zone are analyzed to reconstruct the environment evolution of the area based on high-resolution radiocarbon chronology. The results reveal that the TOC and TN contents of the sediments correlate well with pollen percentage and pollen flux variations during the Holocene, and both reach their peak values simultaneously at 6.7―3.5 ka BP (calendar age, 7.6―3.6 ka BP). Since 6.7 ka BP, both the CaCO3 and organic matter contents of the core have simultaneous variations, and their high values also occur during 6.7―3.5 ka BP. While during 9.0―6.7 ka BP (calendar age, 1.―7.6 ka BP) relatively lower level of organic matter content and pollen flux corre- spond to the higher level of carbonate content. The above relations suggest that during 6.7―3.5 ka BP, the productivity and effective precipitation were greatly improved in the lake drainage area, and this would probably strengthen the hydrodynamic conditions, enhancing organic matter, pollen and carbonate inputs from terrestrial sources. Such processes would account for the enrichment of both organic matter and carbonate in the sediments. While during 9.0―6.7 ka BP, the lower level of or- ganic matter, pollen flux but high carbonate content show depressed productivity and declined vege- tation coverage. The higher carbonate content at this stage would have probably resulted from the higher evaporation ratio of the lake water under relatively drier climate conditions. Therefore, it is in- ferred that during 6.7―3.5 ka BP, the climate was more humid with abundant rainfalls and vegetation was more flourishing in the Lake Daihai area. This can be seen as Holocene Climate Optimum (HCO). As a result, this has evident discrepancies with the traditional notion that the HCO occurs at Early Holocene or early Mid

关键词： Lake Daihai, Mid-Holocene, lacustrine sediments, environmental characteristics.

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Study of thin cloud removal method for CBERS-02.image

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Science china(Technological {1.) 2005年第S2期48卷 91-99页

作者： MA Jianwen1. GU Xingfa1. FENG Chun2.& GUO Jianning2.1. Institute of Remote Sensing Application, chinese academy of {2., beijing 1.01.1. china 2. china Center for Resource Satellite Data and Applications, beijing 1.0073, china 1. Institute of Remote Sensing Application Chinese Academy of Sciences 100101 Beijing China 2.{1. Center for Resource Satellite Data and Applications 100073 Beijing China

The china Brazil Earth Resources Satellite (CBERS) ended the dependence on foreign satellites. Along with the series of CBERS and the enhancement of satellite applications, it is necessary to search correlative data processing methods. Because cloud appears in the atmosphere, an image with clear sky conditions is often hard to obtain. How to remove cloud is an important sector of increasing image quality. An improved homomorphism filtering method is adopted to remove thin cloud qualitatively at first, and all bands are selected to classify pixels. Based on the fact that visible band images contain more aerosol effects than infrared bands, visible bands are used to determine clear or hazy regions and the reflectances of different surface classes in clear regions are calculated. At last the mean reflectance of the same classes in clear and hazy regions is matched to remove cloud. The image visual effect is improved; meanwhile, the ground reflectance is retrieved to meet the needs of remote sensing quantification.

关键词： CBERS-02 cloud removal surface reflectance mean reflectance matching.

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Autonomous satellite constellation orbit determination using the star sensor and inter-satellite links data

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Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 966-974页

作者： GAN QingBo1,2.MA JianBo1 & XU Jin1 1 Purple Mountain Observatory,chinese academy of {2.,Nanjing 2.0008,china 2.Graduate university of chinese academy of {2.,beijing 1.0049,china 1. Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

A method of autonomous orbit determination for a satellite constellation using a star sensor combined with inter satellite links(ISLs) is *** types of simulated observation data,Three-Satellite Constellation ISLs and background stellar observations by a CCD star sensor,are first *** on these data,an observation equation is built for the constellation joint autonomous orbit determination,in which the simulations are *** accuracy of this method with different orbital determination models are analyzed and compared with regard to the effect of potential measurement *** results show that autonomous satellite constellation orbit determination using star sensor measurement and ISLs data is ***,this paper arrives at several conclusions which contribute to extending this method to a more general satellite constellation.

关键词： satellite constellation star sensor inter-satellite links autonomous orbit determination

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Review on the study of entanglement in quantum computation speedup

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chinese Science Bulletin 2007年第16期52卷 2161-2166页

作者： DING ShengChao1,3 & JIN Zhi1,2.1 Institute of Computing Technology,chinese academy of {2.,beijing 100080,china 2.academy of Mathematics and Systems Science,chinese academy of {2.,beijing 100080,china 3 Graduate university of chinese academy of {2.,beijing 100080,china Institute of Computing Technology Chinese Academy of Sciences Beijing 100080 China

The role the quantum entanglement plays in quantum computation speedup has been widely disputed. Some believe that quantum computation's speedup over classical computation is impossible if entan-glement is absent,while others claim that the presence of entanglement is not a necessary condition for some quantum algorithms. This paper discusses this problem systematically. Simulating quantum computation with classical resources is analyzed and entanglement in known algorithms is reviewed. It is concluded that the presence of entanglement is a necessary but not sufficient condition in the pure state or pseudo-pure state quantum computation speedup. The case with the mixed state remains open. Further work on quantum computation will benefit from the presented results.

关键词：量子论量子纠缠量子计算加速模拟

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Testing local realism in P → VV decays

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Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 870-875页

作者： LI JunLi1.& QIAO CongFeng1.2.1.epartment of Physics,Graduate {1. of chinese {2. of sciences,beijing 1.0049,china 2.heoretical Physics Center for Science Facilities(TPCSF),chinese {2. of sciences,beijing 1.0049,china 1. Department of Physics Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Theoretical Physics Center for Science Facilities (TPCSF) Chinese Academy of Sciences Beijing 100049 China

It was found that the vector meson pair from the pseudoscalar decays can form an entangled *** this work we give out detailed explanations on the polarization correlation of the two entangled vector *** is demonstrated that an experimental test of the Clauser-Horne inequality can be carried out through measuring the azimuthal distribution of four pseudoscalars in the cascade decay ηc→ VV →(PP)(PP),and the measurement of this process is feasible with the current running experiments in tau-charm ***,a brief discussion on the polarization correlation of the two vector mesons from B → VV decays is also presented.

关键词： nonlocality test high energy experiment meson decays

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The establishment of crystal position look-up table for positron emission tomography with block detectors

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Science china(Technological {1.) 2009年第8期52卷 2418-2423页

作者： CHAI Pei1.2.& SHAN BaoCi1.1.Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, {1. academy of {2., beijing 1.0049, china 2.Graduate university of {1. academy of {2., beijing 1.0049, china Key Laboratory of Nuclear Analytical Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Graduate university of {1. {2. of sciences Beijing 100049 China

A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors. It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model (GMM). This method has taken full consideration of the characteristics of the GMM and the detector itself. The experimental results have proved that it is simple, reliable, and universal.

关键词： positron emission tomography position look-up table 2.D position histogram

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Floating Population Increase and Its Influence on the Urban Population Situation:A Case Study in beijing

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chinese Journal of Population,Resources and Environment 2005年第1期3卷 27-35页

作者： Wu Peilin 1,2.& Lu Qi 2.1. Shandong university of Technology, Zibo Shandong 2.5049, china 2. Institute of Geographical {2. and Natural Resources Research, chinese academy of {2., beijing 100101, china Shandong university of Technology Zibo Shandong 255049 China Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Floating population is a special population group in china resulting from the implementation of household registration system. This paper uses a set of floating population survey data, population censuses data and statistical data to analyze the increase and influence of floating population on the urban population situations in {1.. It is found that {1. has experienced a rapid increase of floating population since the 1.90s and that the increase of this group has become the key factor of the current population expansion in the city. Its distribution in the urban regions intensified and extended the suburbanization process of the capital. In addition, the population structures of sex, age, education and employment in {1. have changed to some extent due to the influx of floating population.

关键词： Floating population Household registration system (Hukou) Population expansion Suburbanization Population structure beijing

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A two-round honest-verifier zero-knowledge protocol

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Science china(Information {1.) 2010年第5期53卷 954-963页

作者： LIU HanWu 1,2.& LIN DongDai 1 1 The State Key Laboratory of Information Security, Institute of Software, chinese academy of {2., beijing 100190, china 2.Graduate university of the chinese academy of {2., beijing 1.0049, china 1. The State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing 100190 China2. Graduate University of the Chinese Academy of Sciences Beijing 100049 China

Since the concept of zero-knowledge protocols was introduced, it has attracted a lot of attention and in turn showed significant effect on the development of cryptography, complexity theory and other areas. The round complexity of a zero-knowledge protocol is a very important efficiency consideration, and it is required to be as small as possible. Generally, it is desirable to have zero-knowledge protocols with constant numbers of rounds. Goldreich and Oren proved that only languages in BPP have one-round and two-round zero-knowledge protocols. Moreover, they also showed that only languages in BPP have one-round honest-verifier zero-knowledge protocols. The notion of honest-verifier zero-knowledge protocols is highly non-trivial and fascinating itself, and has many other uses. Thus, the problem as to whether there exist two-round honest-verifier zero-knowledge protocols becomes an important open problem. In this paper, we introduce a new simulation technique and present a two-round honest-verifier zero-knowledge protocol for any language in N P under a standard complexity assumption based on this technique.

关键词： proof system argument system zero-knowledge witness indistinguishability black-box one-way permutation commitment scheme zap

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GM-CSF-induced Ca_(2.) -activated non-voltage-dependent inwardly rectifying K_+ channel in murine peritoneal exudate macrophages

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chinese Science Bulletin 1997年第11期42卷 947-952页

作者： ZHANG Xiaofeng, FENG Meifu, WU Caihong and ZHOU Pei’aiState Key Laboratory of Biomembrane and Membrane Biotechnology, chinese academy of {2., beijing 100080, china 1 . In-stitute of Zoology, chinese academy of {2., beijing 100080, china 2.College of Life {2., Peking university, beijing 100871, china State Key Laboratory of Biomembrane and Membrane Biotechnology Chinese Academy of Sciences Beijing 100080 China

GRANULOCYTE-MACROPHAGE colony-stimulating factor(GM-CSF),a member in the family ofglycoprotein cytokines,can not only act to stimulate proliferation of immature progenitors,butalso enhance differentiated functions of mature effector *** has two kinds of biologicaleffects on mature effector cells,*** effect and indirect *** latter is also

关键词： K+ channel patch clamp GM-CSF macrophage.

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