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Reconstruction of precipitation variation from tree rings in recent 1000 years in Delingha, Qinghai

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Science China Earth sciences 2005年第7期48卷 939-949页

作者： SHAO Xuemei1, HUANG Lei1, LIU Hongbin2. LIANG Eryuan1, FANG Xiuqi3.& WANG Lili1 1. institute of Geographic {2. and Natural Resources Research,{2.,{3., China 2. National Climate Center, beijing 100081, China 3. beijing Normal University, beijing 100875, China institute of Geographic sciences Natural Resources Research Chinese Academy of Sciences Beijing 100101 China National Climate Center Beijing 100081 China beijing Normal University Beijing 100875 China

Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1000 years was re- constructed for Delingha. The reconstruction can capture 63.1% of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD152.—163. and 193.—2.01, whereas dry intervals in 142.—1519 and 163.—1741. In ad- dition, the magnitude in precipitation variation was lower before 143. with about 15 mm, but it increased to 3. mm during the period of 143. to 1850. After 1850, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1990s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1000-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the 2.st century.

关键词： northeastern part of the Qaidam Basin tree-ring width series of Qilian juniper precipitation reconstruction in 1000 years.

Geochemical characteristics of rare earth elements in Wuhan section of the Yangtze River

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Journal of Environmental sciences 1995年第1期7卷 44-51页

作者： Wang Lijun Zhang Shen Zhang Chaosheng(institute of Geography,chinese {2. of {3.,beijing 100101,China)Li Xiuxia(institute of High Energy Physics,chinese {2. of {3.,beijing 100080,China) Inst of Geog Chinese Academy of Sciences Beijing China China

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关键词： geochemical characteristics rare earth elements Yangtze River

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science China(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2.ZHANG Lei1,3.& XU JianZhong1,2.1 institute of Engineering Thermophysics,{2. {2. of {3.,beijing 100190,China 2.Key Laboratory of Wind Energy Utilization,{2. {2. of {3.,beijing 100190,China 3.Graduate School of chinese academy of sciences,beijing 100190,China institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing China Graduate School of chinese academy of sciences Beijing China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2.2.0 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

Synthesis and Cation-Mediated Electron Transfer in Fluorescence Quenching of Donor-Acceptor Podands

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chinese Chemical Letters 2000年第9期11卷 767-770页

作者： Hua JIANG Hui Jun XU institute of Photographic Chemistry, chinese academy of sciences, {2., {3. institute of Photographic Chemistry Chinese Academy of Sciences Beijing 100101 China

Reduced rate constants of photoinduced electron transfer in intramolecular fluorescence quenching of donor-acceptor podands induced by cation-complexation are observed in the highly exothermic reactions.

关键词： electron transfer donor acceptor podands

Regional differences and determinants of built-up area expansion in China

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Science China Earth sciences 2007年第12期50卷 1835-1843页

作者： HUANG JiKun1,2.ZHU LiFen3.1 & DENG XiangZheng1,2.1 Center for chinese Agricultural Policy,chinese {2. of {3.,beijing 100101,China 2.institute of Geographic {3. and Natural Resources Research,chinese {2. of {3.,beijing 100101,China 3.Research Center of the Economy of the Upper Reaches of the Yangtze River,Chongqing Technology and Business University,Chongqing 400067,China Center for chinese Agricultural Policy Chinese Academy of Sciences Beijing China institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Research Center of the Economy of the Upper Reaches of the Yangtze River Chongqing Technology and Business University Chongqing China

Based on remote sensing data on land use provided by the chinese academy of sciences and socio-economic data collected by the authors,this paper analyzes the trends and regional differences in built-up area(BUA) expansion in China from the late 1980s to 2.00,and empirically estimates the major determinants of BUA expansion in different regions in 1996―*** 1989―2.00,although China's overall BUA expansion accelerated,the trends differed significantly among *** expansion in the central and western regions accelerated significantly,but it slowed down considerably in the east-ern *** estimation results from our econometric analysis reveal that BUA expansion in the eastern region reached a period when economic growth had no further significant impact on per capita BUA,the land utilization in this region has become more intensive with further expansion of the *** the central and western regions,the BUA has expanded remarkably due to the relatively more flexible land development policies and the relatively cheap land ***,as the econ-omy continues to grow rapidly,policies relating to BUA expansion and cultivated land reductions may face more serious challenges in the central and western regions.

关键词： built-up area, land use, regional difference, determinants, China

Mass Spectrometric Evidence of Heparin Disaccharides for the Catalytic Characterization of A Novel Endolytic Heparinase

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Acta Biochimica et Biophysica Sinica 2004年第12期36卷 840-844页

作者： Yapeng CHAO1,3. Shaoxiang XIONG2. Xiulan CHENG1, and Shijun QIAN1* 1institute of Microbiology,{2., {2. 100080, China 2.enter of Mass Spectrometry, institute of Chemistry,{2., {2. 100080, China 3.raduate School of the{2., {2. 10003., China institute of Microbiology Chinese Academy of SciencesBeijing 100080 China Graduate School of the chinese academy of sciencesbeijing 1000{2. China Center of Mass Spectrometry Institute of Chemistry Chinese Academy of SciencesBeijing 100080 China

Heparinase from different sources can eliminate heparin or/and heparan sulfate into various low-molecular weight heparins with different characteristics. Porcine intestinal mucosa heparin was de- graded into a series of oligosaccharides by a novel heparinase from the species Sphingobacterium. Disaccha- ride components from the digests were separated and purified by ultrafiltration and HPLC. Five major peaks appeared as three types according to their retention time. The mass spectrometry of peak I mainly gave the non-sulfated disaccharide with the mass of 3.9 Da. Peak II and III were indicated as two major monosulfated disaccharides with molecular mass of 417 and 459 Da respectively. Moreover, the peak III represented an N- acetyl disaccharide. Both peak IV and V showed the same mass of 496 Da, hinting that they were disulfate- substituted disaccharides. No trisulfate-substituted disaccharides were detected in the mixture of the heparin digest though they were abundant in the heparin structure. The results revealed that the heparinase might specifically cut the sites with low sulfated domain in heparin.

关键词： electrospray ionization-mass spectrometry heparin disaccharides heparinase high perfor- mance liquid chromatography Sphingobacterium sp.

RESEARCH PROGRESS ON SPACE MUTATION BREEDING OF CROPS IN CHINA

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空间科学学报 1998年第S1期18卷 94-97页

作者： JIANG Xing-cun HU Zan-min (institute of genetics, The{2.,{3.)

Mutagenic breeding has been carried out in China since 1986 by on boarding the crop seeds in recoverable satellite and balloon. Good results have been obtained. Some new crop lines with high-yield, good-quantity, dise... 详细信息

关键词： Space Mutagenic breeding

Simulating the impacts of climate variation and land-cover changes on basin hydrology: A case study of the Suomo basin

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Science China Earth sciences 2005年第9期48卷 1501-1509页

作者： CHEN Junfeng1,2. LI Xiubin2.& ZHANG Ming2.1. institute of Remote Sensing & GIS, Peking University, beijing 100871, China 2. institute of Geographical {3. and Natural Resources Research, chinese academy of sciences, beijing 100101, China institute of Remote Sensing & GIS Peking University Beijing China institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing Chin

Impacts of land cover changes on watershed hydrology have been a long-term academic concern with acute dispute. But little attention has been paid to such effects on mesoscale river basins, where the society has a closer link to river hydrology. The present study focuses on a mesoscale river basin, the Suomo Basin that is located on the upper reaches of the Yangtze River. Land covers in the basin in the years 1970, 1986 and 1999 were mapped. A lumped hydrologic model, CHARM, and a distributed hydrologic model, SWAT, were used to model the impacts of both land-cover change and climate variation on river runoff during the past four decades. The results show that the contribution of climate variation to the change of runoff regime makes up 60%―80%, while that of land cover changes only 2.%.

关键词： climate variation, land-cover changes, Suomo Basin, CHARM model, SWAT model.

Formal Verification under Unknown Constraints

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Wuhan University Journal of Natural sciences 2005年第1期10卷 43-46页

作者： LI Guang-hui 1,2.3., LI Xiao-wei 2.3.. School of Information Engineering, Zhejiang Forestry College, Hangzhou 3.13.0, Zhejiang, China 2. institute of Computing Technology, chinese academy of sciences, {2. 100080, China 3. Graduate School of the chinese academy of sciences, {2. 10003., China School of Information Engineering Zhejiang Forestry College Hangzhou Zhejiang China institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China

We present a formal method of verifying designs with unknown constraints (e.g., black boxes) using Boolean satisfiability (SAT). This method is based on a new encoding scheme of unknown constraints, and solves the corresponding conjunctive normal form (CNF) ***,this method can avoid the potential memory explosion, which the binary decision diagram (BDD) based techniques maybe suffer from, thus it has the capacity of verifying large designs. Experimental results demonstrate the efficiency and feasibility of the proposed method.

关键词： formal verification unknown constraints black box Boolean satisfiability Boolean comparison