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Two-dimensional line thermal

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Communications in Nonlinear Science and Numerical Simulation 2000年第3期5卷 91-97页

作者： G. Q. CHEN and J. H. W. LEE(a) Centre for Environmental Sciences / state key {2. for Thrbulence Research, Peking University, beijing 100871 b)Institute of Environmental Sciences, beijing normal University, beijing 100875 e-mail: gqchen@ns.nlspku. a Centre for Environmental Sciences / state key {2. for Turbulence Research Peking University Beijing 100871 China Institute of Environmental Sciences Beijing Normal University Beijing 100875 China

The time evolution of a two-dimensional line thermal - a turbulent flow produced by an initial element with significant buoyancy released in a large water body, is numerically studied using the two-equation k-e model ... 详细信息

关键词： thermal and plume environmental fluid mechanics

Automatic composition of information-providing web services based on query rewriting

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Science china(Information Sciences) 2012年第11期55卷 2428-2444页

作者： ZHAO WenFeng,LIU ChuanChang & CHEN JunLiang state key {2. of Networking and Switching Technology,beijing University of Posts and Telecommunications,beijing 100876,china state key {2. of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China

Compared with normal web services,information-providing services have unique features that have seldom been considered in existing research on the automatic composition of web *** this paper,we present a simple,yet well-formed,semantic-based capability model for information-providing web services,which can express such features as not modifying the world state and not requiring all input/output parameters to be supplemented with class information as *** then present a corresponding automatic composition method derived from a query rewriting algorithm,MiniCon,used in the data integration *** method adequately utilizes previous features,enables primitive semantic reasoning,and can generate executable BPEL scripts *** of the method is complementary to traditional search-based *** on a typical type of problem show that the method is usable in practice.

关键词： web services automatic composition query rewriting data integration ontology semantic web

Entropy product measure for multipartite pure states

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 606-615页

作者： CAO Wancang1,2. LIU Dan2. PAN Feng3 & LONG Guilu2.4 1. Department of Physics, Chifeng College, Chifeng 02.001, china 2. key {2. for Quantum Information and Measurements, Department of Physics, Tsinghua University, beijing 100084, china 3. Department of Physics, Liaoning normal University, Dalian 11602., china 4. key {2. for Atomic and Molecular Nano-Sciences, Tsinghua University, beijing 100084, china Correspondence should be addressed to Long Guilu Department of Physics Chifeng College Chifeng China key laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Beijing China Department of Physics Liaoning Normal University Dalian China key laboratory for Atomic and Molecular Nano-Sciences Tsinghua University Beijing China

An entanglement measure for multipartite pure states is formulated using the product of the von Neumann entropy of the reduced density matrices of the constituents. Based on this new measure, all possible ways of the maximal entanglement of the triqubit pure states are studied in detail and all types of the maximal entanglement have been compared with the result of ‘the average entropy’. The new measure can be used to calculate the degree of entanglement, and an improvement is given in the area near the zero entropy.

关键词： multipartite pure state von Neumann entropy entanglement measure

Study on the changes of water cycle and its impacts in the source region of the Yellow River

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Science china(Technological Sciences) 2004年第Z1期47卷 142-151页

作者： ZHANG Shifeng1, JIA Shaofeng1, LIU Changming1, CAO Wenbing2. HAO Fanghua3, LIU Jiuyu4 & YAN Huayun5 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china 2. china University of Geosciences, beijing 100083, china 3. beijing normal University, beijing 100875, china 4. Bureau of Hydrology of Yellow River Conservancy Commission, Zhengzhou 450003, china 5. Bureau of Hydrology and Water Resource Investigation of Qinghai Province, Xining 810001, china Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China china University of Geosciences Beijing China beijing normal University Beijing China Bureau of Hydrology of Yellow River Conservancy Commission Zhengzhou China Bureau of Hydrology and Water Resource Investigation of Qinghai Province Xining China

The water cycle in the source region of the Yellow River underwent great changes in the 1990s. The major features of the changes are as follows: the gauged runoff declined significantly while the precipitation increased slightly, and the runoff process was more concentrated on the flood season. Water balance analyses indicate that the pondage was kept in the status of negative equilibrium, causing eco-environmental problems. The runoff decrement is due to evaporation increment in this region. Studies show that the runoff process in this region is closely related to that of the other hydrological stations in the upper reaches. When the runoff declines in the source regions, the amount of water also declines in the whole upper reaches of the Yellow River, affecting the balance between water demand and supply. Meanwhile changes will take place in the water cycle of the river course system when the eco-environment deteriorates. The trend of water cycle change in the source region is that the runoff will keep declining with the increment of evaporation caused by temperature rise in the northwest of china in the 2.st century. But the hydraulic engineering in the source region will help to mitigate the deterioration of local eco-environment system, though the impacts to the lower reaches of this project may not be the case.

关键词： source region of the Yellow River, water cycle, evaporation, negative equilibrium.

The synthesis, bioactivity and paramagnetic resonance of angiotensin Ⅱ and its spin labelled derivative

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Chinese Science Bulletin 1997年第21期42卷 1843-1846页

作者： WANG Rui, LI Xiaoxu, HU Xiaoyu, NI Jingman, LI Changling and LU Jingfen1. Department of Biology, state key {2. of Applied Organic Chemistry, Lanzhou 730000, china 2. Department of Chemistry, Lanzhou University, Lanzhou 730000 3. state key {2. of Natural and Biomimetic Drugs, beijing Medical U-niversity, beijing 100083, china. Department of Biology State Key Laboratory of Applied Organic Chemistry Lanzhou China Department of Chemistry Lanzhou University Lanzhou state key {2. of Natural and Biomimetic Drugs Beijing Medical University Beijing China

ANGIOTENSIN Ⅱ(Ang Ⅱ) is an important constituent in renin-angiotension system (RAS).The amino acid sequence of Ang Ⅱ is DRVYIHPF. Ang Ⅱ plays an important role both inmaintenance of normal blood pressure and in occurrence of hypertension. Ang Ⅱ binding re-ceptor can induce many kinds of physiological effects. Spin labeling is an effective method thatgreatly deepened the knowledge in structure, movement and interaction of biologicalmolecules. For example, it has been used in studying interaction of antigen and antibody suc-

关键词： spin labelled angiotensin Ⅱ solid phase peptide synthesis bioactivity electron spin resonance.

Plausible impact of global climate change on water resources in the Tarim River Basin

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Science china Earth Sciences 2005年第1期48卷 65-73页

作者： CHEN Yaning & XU Zongxue Xinjiang Institute of Ecology & Geography, Chinese Academy of Sciences, Urumqi 830011, china College of Environmental Sciences, beijing {2. University, beijing 100875, china Xinjiang Institute of Ecology & Geography Chinese Academy of Sciences Urumqi China College of Environmental Sciences Beijing Normal University Beijing China

Combining the temperature and precipitation data from 77 climatological stations and the climatic and hydrological change data from three headstreams of the Tarim River: Hotan, Yarkant, and Aksu in the study area, the plausible association between climate change and the variability of water resources in the Tarim River Basin in recent years was investigated, the long-term trend of the hydrological time series including temperature, precipitation, and streamflow was detected, and the possible association between the El Ni(n)o/Southern Oscillation (ENSO) and these three kinds of time series was tested. The results obtained in this study show that during the past years, the temperature experienced a significant monotonic increase at the speed of 5%, nearly 1℃ rise; the precipitation showed a significant decrease in the 1970s, and a significant increase in the1980s and 1990s, the average annual precipitation was increased with the magnitude of 6.8 mm per decade. A step change occurred in both temperature and precipitation time series around 1986, which may be influenced by the global climate change. Climate change resulted in the increase of the streamflow at the headwater of the Tarim River, but the anthropogenic activities such as over-depletion of the surface water resulted in the decrease of the streamflow at the lower reaches of the Tarim River. The study result also showed that there is no significant association between the ENSO and the temperature, precipitation and streamflow.

关键词： climate change, hydrological change, temperature, precipitation, streamflow, Tarim River.

Spatial prediction and analysis of Himalayan marmot plague natural epidemic foci in china based on HJ-1 satellite data

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Science china Earth Sciences 2010年第S1期53卷 8-15页

作者： GAO MengXu1,4,LI XiaoWen1,2.CAO ChunXiang1,ZHANG Hao1,LI Qun3,ZHOU Hang3 HE QiSheng1,4,XU Min1,4,ZHAO Jian1,4,ZHENG Sheng1,4 & CHEN Wei1,4 1state key {2. of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and beijing normal University,beijing 100101,china 2.chool of Geography,beijing normal University,beijing 100875,china 3Office for Disease Control and Emergency Response,Chinese Center for Disease Control and Prevention,beijing 102.06,china 4Graduate University of Chinese Academy of Sciences,beijing 100049,china state key {2. of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate University of Chinese Academy of Sciences Beijing China School of Geography Beijing Normal University Beijing China Office for Disease Control and Emergency Response Chinese Center for Disease Control and Prevention Beijing China

Plague,caused by the gram-negative bacterium Yersinia pestis,is a serious and rapidly progressing illness in humans that can be fatal if not treated *** Qinghai-Tibet Plateau is the largest area of natural Himalayan marmot(Marmota himalayana) plague foci in china and covers more than 630000 *** County in Gansu Province is a part of this natural focus of plague and was chosen as a study *** study used an ecological niche modeling(ENM) approach to predict the potential distribution of the Himalayan *** and Disaster Monitor Satellite(HJ-1) data was used to investigate environment factors that affect plague host animal *** animal point data from active surveillance was combined with environmental variables from the HJ-1 satellite and other databases,and the models of the potential distribution of Himalayan marmot were produced with the Genetic Algorithm for Rule-Set Production(GARP).The probability of marmot presence was divided into 0-5%,5%-2.%,2.%-40%,40%-80%,and 80%-100% *** with 80%-100% probability exhibited the greatest potential for the presence of Himalayan *** to the predicted potential distribution of Himalayan marmot in the study area,active surveillance of plague hosts and plague control and prevention could be more efficient.

关键词： Himalayan marmot plague spatial prediction GARP HJ-1 satellite

Analysis of forest backscattering characteristics based on polarization coherence tomography

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Science china(Technological Sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2.CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 2. Institute of Geo-Spatial Information Science and Technology,University of Electronic Science and Technology of china,Chengdu 610054,china 2.{2. key laboratory of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and beijing normal University,beijing 100101,china 3Institute of Forest Resources Information Technique of Chinese Academy of Forestry,beijing 100091,china 4 School of Electronic Engineering,University of Electronic Science and Technology of china,Chengdu 610054,china Institute of Geo-Spatial Information Science and Technology University of Electronic Science and Technology of China Chengdu China state key {2. of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Institute of Forest Resources Information Technique of Chinese Academy of Forestry Beijing China School of Electronic Engineering University of Electronic Science and Technology of China Chengdu China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2.D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

MB_8^(2.) (M=Be,Mg,Ca,Sr,and Ba):Planar octacoordinate alkaline earth metal atoms enclosed by boron rings

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Science china Chemistry 2010年第8期53卷 1737-1745,1829-1832页

作者： PU ZhiFeng1,GE MaoFa1 & LI QianShu2.1state key {2. for Structural Chemistry of Unstable and Stable Species beijing National {2. for Molecular Sciences (BNLMS) Institute of Chemistry,Chinese Academy of Sciences,beijing 100190,china 2.enter for Computational Quantum Chemistry,South china normal University,Guangzhou 510631,china state key {2. for Structural Chemistry of Unstable and Stable Species beijing National laboratory for Molecular Sciences (BNLMS) Institute of Chemistry Chinese Academy of Sciences Beijing China Center for Computational Quantum Chemistry South China Normal University Guangzhou China

Complexes involving planar octacoordinate alkaline earth metal atoms in the centers of eight-membered boron rings have been investigated by two density functional theory (DFT) ***82.with D8h symmetry is predicted to be stable,both geometrically and electronically,since a good match is achieved between the size of the central beryllium atom and the eight-membered boron *** contrast,the other alkaline earth metal atoms cannot be stabilized in the center of a planar eight-membered boron ring because of their large *** following the out-of-plane imaginary vibrational frequency,pyramidal C8v MgB82.,CaB82.,SrB82.,and BaB82.structures are *** presence of delocalized π and σ valence molecular orbitals in D8h BeB82.gives rise to aromaticity,which is reflected by the value of the nucleus-independent chemical *** D8h BeB82.structure is confirmed to be the global minimum on the potential energy surface.

关键词： density functional theory octacoordinate alkaline earth metal aromatic molecular orbital