维普中文期刊产品整合服务
37篇 您的检索式:作者名="Xia 3"
    题名 作者 年代 出处 被引量
1Sr-Nd isotopic compositions of the Changjiang sediments: Implications for tracing sediment sources显示文摘The suspended particulate and fine-grained floodplain sediments were collected from the main stream and tributaries of the Changjiang River for Sr-Nd isotopic measurements. The εNd(0) values gradually decrease downstream from -10.8 on average in the upper reaches to -12.3 in the lower reaches, whereas the 87Sr/86Sr ratios increase correspondingly, averaging 0.721899 and 0.725826 respectively in the upper and middle-lower reaches. The compositional variations primarily reflect the complex con- trols of provenance rocks, chemical weathering, and sediment characters between different catchments, among which the abnormal Sr-Nd isotopic compositions of the Yalong, Fujiang, Tuojiang and Yuanjiang rivers indicate the sediment provenance contributions from the Emeishan Basalt in the upper reaches and the old metamorphic and siliceous rocks in the middle-lower reaches. The Sr-Nd isotopic ratios of the Changjiang sediments can better reflect the average composition of weathered continental crust compared to other major rivers in the world because of the unique source rock types in the Changjiang drainage basin. The recognition of the Sr-Nd isotopic systematics of the Changjiang sediments will contribute to our understanding of the Changjiang evolution history and continental weathering processes during the Cenozoic, and also to reconstructing the paleoenvironmental changes in East China and the marginal seas.YANG ShouYe1?, JIANG ShaoYong2, LING HongFei2, XIA XiaoPing3, SUN Min3 & WANG DeJie4 1 State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 2 State Key Laboratory for Mineral Deposit Research, Nanjing University, Nanjing 210093, China 3 Departmen of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China 4 Development Research Center, China Geological Survey, Beijing 100083, China 2007Science China Earth Sciences2007,50,10:32
2A study of interaction between surface water and groundwater using environmental isotope in Huaisha River basin显示文摘The surface water and groundwater are important components of water cycle, and the interaction between surface water and groundwater is the important part in water cycle research. As the effective tracers in water cycle research, environmental isotope and hydrochemistry can reveal the interrelationships between surface water and groundwater effectively. The study area is the Huaisha River basin, which is located in Huairou district, Beijing. The field surveying and sampling for spring, river and well water were finished in 2002 and 2003. The hydrogen and oxygen isotopes and water quality were measured at the laboratory. The spatial characteristics in isotope and evolution of water quality along river lines at the different area were analyzed. The altitude effect of oxygen isotope in springs was revealed, and then using this equation, theory foundation for deducing recharge source of spring was estimated. By applying the mass balance method, the annual mean groundwater recharge rate at the catchment was estimated. Based on the groundwater recharge analysis, combining the hydrogeological condition analysis, and comparing the rainfall-runoff coefficients from the 1960s to 1990s in the Huaisha River basin and those in the Chaobai River basin, part of the runoff in the Huaisha River basin is recharged outside of this basin, in other words, this basin is an un-enclosed basin. On the basis of synthetically analyses, combining the compositions of hydrogen and oxygen isotopes and hydrochemistry, geomorphology, geology, and watershed systems characteristics, the relative contributions between surface water and groundwater flow at the different areas at the catchments were evaluated, and the interaction between surface water and groundwater was re- vealed lastly.SONG Xianfang1, LIU Xiangchao1, 2, XIA Jun1, YU Jingjie1 & TANG Changyuan1, 3 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences and Natural Re- sources Research, Chinese Academy of Sciences, Beijing 100101, China 2. College of River and Ocean, Chongqing Jiaotong University, Chongqing 400074, China 3. Chiba University, Chiba 263-8522, Japan 2006Science China Earth Sciences2006,49,12:34
3Neuroprotection of aucubin in primary diabetic encephalopathy显示文摘Hippocampal neuronal apoptosis accompanied by impairment of cognitive function occurs in primary diabetic encephalopathy. In this study, we investigated the neuroprotective mechanism of the iridoid glycoside, aucubin, using rats (n=8). Diabetes mellitus was induced in the rats by intraperitoneal (i.p.) injection of streptozotocin (60 mg/kg body weight). After 65 d, half of the DM rats were administered aucubin (5 mg/kg; i.p.) for 15 d, yielding treatment DM+A. A third group of rats received no strepto- zotocin or aucibin, and served as controls (CON). Encephalopathy was assessed using Y-maze be- havioral testing. Rats were euthanized on Day 87, and hippocampi were excised for visual (light and transmission electron microscopic) and immunochemical (Western blot; immunohistochemical) as- sessments of the CA1 subfield for apoptosis and expression of regulatory proteins Bcl-2 and Bax. Treatment responses to all the parameters examined (body weight, plasma glucose, Y-maze error rates, pyramidal cell ultrastructure, proportions of apoptotic cells, levels of expression of Bcl-2 and Bax, and survivability of neuronal cells) were identical: there were highly significant differences between DM and CON groups (P<0.001), but the effects were significantly moderated (P<0.01) in DM+A compared with DM. These findings confirm the association of apoptosis with the encephalopathic effects of diabetes mellitus, and suggest a major role of the expression levels of Bcl-2 and Bax in the regulation of apop- totic cell death. All of the results suggest that aucubin could effectively inhibit apoptosis by modulating the expressions of Bcl-2 and Bax genes.XUE HongYu1, JIN LiJi1,2, JIN Lei1, ZHANG Peng1, LI DanQing4, XIA YanQiu1, LU YaNan1 & XU YongPing1,3 1 Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian 116024, China 2 State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China 3 Dalian SEM Bioengineer and Biotech Ltd., Dalian 116024, China 4 The Second Affiliated Hospital, Dalian Medical University, Dalian 116024, China 2008Science China(Life Sciences)2008,51,6:22
4Southeastern extension of the Red River fault zone (RRFZ) and its tectonic evolution significance in western South China Sea显示文摘Recent geophysical surveys and basin modeling suggest that the No.1 fault in the Ying- gehai basin (YGHB) is the seaward elongation of the Red River fault zone (RRFZ) in the South China Sea (SCS). The RRFZ, which separates the South China and Indochina block, extends first along the Yuedong fault, offshore of Vietnam, and then continues southward and breaks off into two branches: the Lupar fault and the Tinjia fault. The southern extension of the Lupar fault dies out beneath the NW Borneo while the Tinjia fault extends southeast and reaches the Brunei-Sabah area. According to the gravity and geomagnetic data, and the tectonic evolution of the basins, there are different evolution histories between the Wan’an basin (WAB) and the basins in the Nansha block. The Tinjia fault may be the boundary between the Balingian block and the Nansha block. Hence, the line linking the Yue- dong fault and the Tinjia fault, which both are continental margin faults and strike-slip ones in the geological evolution histories, constitute the boundary between the Indochina and Nansha block. The Lupar fault, in contrast, is an intraplate fault within the Indochina block. The results provide new hints for reconstructing the tectonic evolution history of the RRFZ and the opening of the SCS, and also a framework for hydrocarbon prospecting in the region.LIU Baoming1,2,3, XIA Bin1, LI Xuxuan1,3, ZHANG Minqiang1,3, NIU Binhua2, ZHONG Lifeng1, JIN Qinghuan1,4 & JI Shaocheng1,5 1. Key Laboratory of Marginal Sea Geology and Resources, Chinese Academy of Sciences,Guangzhou 510640, China 2. China University of Geosciences (Beijing), Beijing 100083, China 3. Research Center of Science & Technology Department, CNOOC, Beijing 100027, China 4. Guangzhou Marine Geological Survey, Ministry of Land & Resources, Guangzhou 510075, China 5. Ecole Polytechnique Montreal, H3C3A7, Canada 2006Science China Earth Sciences2006,49,8:20
5Preliminary study on the origin identification of natural gas by the parameters of light hydrocarbon显示文摘The light hydrocarbon composition of 209 natural gas samples and individual light hydrocarbon carbon isotopes of 53 natural gas samples from typical humic-sourced gas and sapropelic-sourced gas in the four basins of China have been determined and analyzed.Some identification parameters for humic-sourced gas and sapropelic-sourced gas are proposed or corrected.The differences of compound-specificδ13C value of individual light hydrocarbon between humic-sourced gas and sapropelic-sourced gas have been founded.The humic-sourced gas has the distribution ofδ13C benzene > -24‰,δ13C toluene >-23‰,δ13C cyclohexane >-24‰andδ13C methyl cyclohexane >-24‰,while the sapropelicsourced gas has the distribution ofδ13C benzene <-24‰,δ13C toluene <-24‰,δ13C cyclohexane <-24‰and δ13C methyl cyclohexane <-24‰.Among the components of C7 light hydrocarbon compound,such as normal heptane(nC7),methyl cyclohexane(MCH)and dimethyl cyclopentane(ΣDMCP),etc,relative contents of nC7 and MCH are influenced mainly by the source organic matter type of natural gas.Therefore,it is suggested that the gas with relative content of nC7 of more than 30%and relative content of MCH of less than 70%is sapropelic-sourced gas,while gas with relative content of nC7 of less than 35%and relative content of MCH of more than 50%is humic-sourced gas.Among components of C5-7 aliphatics, the gas with relative content of C5-7 normal alkane of more than 30%is sapropelic-sourced gas,while the gas with relative content of C5-7 normal alkane of less than 30%is humic-sourced gas.These paremeters have been suggested to identify humic-sourced gas and sapropelic-sourced gas.HU GuoYi 1,2,3 ,LI Jian 1,2 ,LI Jin 1,2 ,LI ZhiSheng 1,2 ,LUO Xia 1,2 ,SUN QingWu 1,2 &MA ChengHua 1,2 1 Research Institute of Petroleum Exploration and Development(Langfang Branch),Petrochina,Langfang 065007,China 2 The Key Laboratory of Gas Formation and Development,Petrochina,Langfang 065007,China 3 College of Geo-Resources and Information,China University of Petroleum,Beijing 102200,China 2008Science China Earth Sciences2008,51,S1:19
6Simulation of freezing and melting of soil on the northeast Tibetan Plateau显示文摘Using observational data spanning the period from February to December 2009 and recorded at the Suli station in Qinghai Province,the land-surface model CLM3.0 was employed to simulate the freezing and melting of soil.The results indicate that the simulated soil temperature is higher than the observed soil temperature and the ultimate thawing date is earlier than the observed date during the melting period.During the freezing period,the simulated soil temperature is lower than the observed soil temperature and the ultimate freezing of the deep soil is earlier than that observed.Overall,the simulation of freezing is better than that of melting,and the simulation of a shallow layer is better than that of a deeper layer.In the original CLM3.0,it is assumed that frozen soil begins to melt when the soil temperature exceeds 0C,which is inconsistent with observations.The critical freeze-thaw temperature was calculated according to thermodynamics equations and the freeze-thaw condition was modified.In this work,the melting rate for frozen soil was reduced using the modified scheme,and the simulated soil temperature was lowered. Meanwhile,the refreezing of soil during the melting season was well simulated and more closely matched observations.Additionally,it was found that the rates of melting and freezing differ,with the former being slower than the latter,but refreezing during the melting season is rather quick.XIA Kun 1,2,3,LUO Yong 2,4,5 & LI WeiPing 2 1 Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China 2National Climate Center,China Meteorological Administration,Beijing 100081,China 3Graduate University of Chinese Academy of Sciences,Beijing 100049,China 4 Center for Earth System Science,Tsinghua University,Beijing 100084,China 5Key Laboratory of Earth System Numerical Simulation,Ministry of Education,Beijing 100084,China 2011Chinese Science Bulletin2011,56,20:14
7Inflammatory bowel disease in Hubei Province of China显示文摘InflammatoryboweldiseaseinHubeiProvinceofChinaXIABing1,S.SHIVANANDA2,ZHANGGuiShui1,YIJiYun1,JBACRUSIUS3andASPEN~A3Subjecthe...XIA Bing 1, S. SHIVANANDA 2, ZHANG Gui Shui 1, YI Ji Yun 1, JBA CRUSIUS 3 and AS PE N~ A 3 1997World Journal of Gastroenterology1997,3,2:12
8Diet and gastric cancer:a case-control study in Fujian Province,China显示文摘NTRODUCTIONChangleandFuqingcitiesarelocatedinthesoutheasternpartofFujianProvince,Chinawithahighincidenceofgastriccancer.Howev...YE Wei Min 1, YI Ying Nan 1, LUO Ren Xia 2, ZHOU Tian Shu 3, LIN Ru Tao 1 and CHEN Gui Dong 3 1998World Journal of Gastroenterology1998,4,6:12
9Global absorption center map of the mafic minerals on the Moon as viewed by CE-1 IIM data显示文摘Determining the global distribution of minerals on the Moon has been an important goal of lunar science. Hyperspectral remote sensing is an important approach to acquiring minerals on the Moon on the global scale. The wavelength of the absorption band center is the key parameter for identifying minerals with reflectance spectra as well as remote sensing data. The global absorption center map of the mafic minerals of the Moon was produced for the first time with the Chang’E-1 IIM data. This map shows the global distribution of mafic minerals such as orthopyroxenes, clinopyroxenes, and olivine and even plagioclase feldspar of the Moon. The validation for some representative areas indicates that the global map is reliable and even more detailed than the results derived from Clementine-data. Moreover, our method is insensitive to the topography and viewing and illumination geometries. The global absorption band center map not only contributes to the lunar science research, but also has other implications to be further studied. Moreover, the preprocessing methods such as calibration and correction introduced in this study can be useful in other research with IIM data.WU YunZhao 1,4* , ZHANG Xia 2 , YAN BoKun 3 , GAN FuPing 3 , TANG ZeSheng 4 , XU AoAo 4 , ZHENG YongChun 5 & ZOU YongLiao 5 1 School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093, China 2 Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101, China 3 Institute for Remote Sensing Method, China Aero Geophysical Survey and Remote Sensing Center for Land and Resources, Beijing 100083, China 4 Collaborative Research Laboratory on Lunar and Planetary Exploration, Macao University of Science and Technology, Taipa, Macao, China 5 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2010Science China(Physics,Mechanics & Astronomy)2010,53,12:11
10Tidally induced upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer显示文摘MASNUM wave-tide-circulation coupled numerical model (MASNUM coupled model, hereinafter) is de-veloped based on the Princeton Ocean Model (POM). Both POM and MASNUM coupled model are ap-plied in the numerical simulation of the upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer. The upwelling mechanisms are analyzed from the viewpoint of tide, and a new mechanism is proposed. The study suggests that the tidally inducing mechanism of the upwelling in-cludes two dynamic aspects: the barotropic and the baroclinic process. On the one hand, the residual currents induced by barotropic tides converge near the seabed, and upwelling is generated to maintain mass conservation. The climbing of the residual currents along the sea bottom slope also contributes to the upwelling. On the other hand, tidal mixing plays a very important role in inducing the upwelling in the baroclinic sea circumstances. Strong tidal mixing leads to conspicuous front in the coastal waters. The considerable horizontal density gradient across the front elicits a secondary circulation clinging to the tidal front, and the upwelling branch appears near the frontal zone. Numerical experiments are de-signed to determine the importance of tide in inducing the upwelling. The results indicate that tide is a key and dominant inducement of the upwelling. Experiments also show that coupling calculation of the four main tidal constituents (M2, S2, K1, and O1), rather than dealing with the single M2 constituent, im-proves the modeling precision of the barotropic tide-induced upwelling.L XinGang1,2,3,4, QIAO FangLi1,2, XIA ChangShui1,2 & YUAN YeLi1,2 1 The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China 2 Key Laboratory of Marine Science and Numerical Modeling (MASNUM), State Oceanic Administration, Qingdao 266061, China 3 Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 4 Graduate University of the Chinese Academy of Sciences, Beijing 100039, China 2007Science China Earth Sciences2007,50,3:9
11Efficient visualization techniques for high resolution remotely sensed data in a network environment显示文摘There are three major research hotspots in efficient visualization techniques of high resolution remotely sensed data in network environment: the data organiza-tion and access in disk storage,the image data stitching and fitting methods,and the network transfers and access. In this paper a new method of 'Big File' organi-zation for improving the storage access efficiency of high resolution remote data is presented; a 'virtual data source' concept is introduced to solve the stitching problem of remotely sensed data from different sources with different resolutions; a remotely sensed data access engine design based on ATL technique is discussed to process the network transfers and access of remotely sensed data. All these techniques have been adopted in a prototype of digital China named 'ChinaStar'.WENG JingNong1,WU Lun2,HUANG Jian1,XIA YuBin3 & CAI Heng1 1 College of Software,Beihang University,Beijing 100083,China 2 Institute of Geographical Information System and Remote Sensing,Peking University,Beijing 100871,China 3 College of Computer,Beihang University,Beijing 100083,China 2008Science China(Technological Sciences)2008,51,S1:8
12Differential Hydrological Grey Model (DHGM) with self-memory function and its application to flood forecasting显示文摘This paper addresses a problem of flood forecasting with the self-memory function. Considering flood forecasting’s uncertainty and updating demand, a hybrid hydrological model, namely Differential Hy- drological Grey Model with self-memory function (DHGM-SM), is developed. The model has two fold features. One is to establish a self-memorization equation linked with DHGM, that could extract useful information from past data series and realize updating of hydrological dynamic process. The other is that this model has higher efficiency relative to original hydrological model without self-memory func- tion. This approach was applied to river flow forecasting of two representative basins in Tunxi of South China and Daqinggou of North China. It is shown that this hybrid method has satisfactory forecasting accuracy by examination of both calibration and validation.CHEN XiangDong1, XIA Jun1,2 & XU Qian3 1 Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2 State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China 3 School of Hydrology and Water Resources, Hohai University, Nanjing 210098, China 2009Science China(Technological Sciences)2009,52,4:8
13Ternary geochemical-tracing system in natural gas accumulation显示文摘The establishment of geochemical-tracing system of gas generation and accumulation is helpful to re-elucidating the gas migration and accumulation in time and space. To deduce the complex process of gas accumulation, a ternary geochemical-tracing system is set up, according to stable isotope inheritance of source rocks, kinetic fractionation of stable isotopes, time-accumulating effect of noble gas isotopes, mantle-derived volatile inheritance, and organic molecule inheritance of light hydrocarbons and thermally kinetic fractionation in their generation, in combination with the previous achievements of gas geochemistry and geochemical parameters of gas-source correlation. There are tight interactions for the geochemical parameters with much information about parent inheritance and special biomarkers, in which they are confirmed each other, reciprocally associated and preferentially used for the requirement so that we can use these geochemical parameters to effectively demonstrate the sources of natural gas, sedimentary environments and thermal evolution of source rocks, migration and accumulation of natural gas, and rearrangement of natural gas reservoirs. It is necessary for the ternary geochemical-tracing system to predict the formation of high efficient gas reservoir and their distribution in time and space.LIU WenHui1,2?, CHEN MengJin3, GUAN Ping4, ZHENG JianJing2, JIN Qiang5, LI Jian6, WANG WanChun2, HU GuoYi3, XIA YanQing2 & ZHANG DianWei2 1 Exploration & Production Research Institute, SINOPEC, Beijing 100083, China 2 Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China 3 Research Institute of Petroleum Exploration & Production, PetroChina, Beijing 100083, China 4 School of Earth and Space Sciences, Peking University, Beijing 100871, China 5 China University of Petroleum (East China), Dongying 257062 ,China 6 Longfang Branch, Research Institute of Petroleum Exploration & Production, PetroChina, Longfang 065007, China 2007Science China Earth Sciences2007,50,10:7
14Role of uterine natural killer cells in angiogenesis of human decidua of the first-trimester pregnancy显示文摘Decidualization is accompanied by extensive angiogenesis, which is an essential step in the maturation of new blood vessels in mammalian pregnancy. The purpose of this study was to determine a distribution of uNK cells (CD56+ uNK or CD56bright cells) in human decidua of the first-trimester pregnancy, and investigate whether uNK cells in human decidua could express vascular endothelial growth factor (VEGF-A) and/or angiopoietin2 (Ang2). Our immunohistochemical staining results demonstrated that a great amount of uNK (CD56+) cells scattered throughout the decidual stroma and near endometrial gland and spiral vessels in human decidua. The protein expression of VEGF-A and Ang2 was detected in decidual stroma cells, capillary endothelial cells and glandular cells in tissue specimens. There was a positive correlation between microvessel density (MVD) and the number of the CD56-positive uNK cells in decidual stroma, and also between the number of the CD56-positive uNK cells and VEGF-A protein expression in the tissue. In addition, we found that uNK cells in human decidua could express VEGF-A mRNA, but not Ang2 mRNA, in isolated uNK cells in human decidua of the first-trimester gestation by combination of LCM and Nested-PCR. Our study indicated that uNK cells, through expressing VEGF-A, may play an important role in the angiogenic response at the time of human decidualization and early placenta development.LI GuoHua1, HUANG Wei1, XIA QingJie2, YANG KaiXuan3, LIU RaoFang1, ZHU HuiLi1 & JIANG Wei4 1 Department of Reproductive Endocrinology, West China Second University Hospital, Sichuan University, Chengdu 610041, China 2 West China Research Laboratory of Molecular Genetics, Sichuan University, Chengdu 610041, China 3 Department of Pathology, West China Second University Hospital, Sichuan University, Chengdu 610041, China 4 Department of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China 2008Science China(Life Sciences)2008,51,2:7
15Isotope Method for Confined Groundwater Recharge of the Lower Reaches of the Heihe River,Inner Mongolia,China显示文摘环境同位素被使用了分析限制地下水在 Heihe 河的更低的活动范围再装,内部蒙古。CFC 被认为是决定地下水的日期的示踪物,是的日期不到 45 一。在除 Heihe 河力量的表水以外的 Gurinai 区域和 Ejin 盆以内的限制地下水从 Qilian 山或 / 并且西藏的高原从降水发源。深限制的地下水溢出进上面的含水土层并且出现进地面,形成在内的弹簧和湖 thelow 躺区域。recharge 体积被估计在 400 百万立方的米附近。CHEN Jiansheng ZHAO Xia FAN Zhechao and WANG Jiyang 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China 2 Institute of Isotope Hydrology Research,Hohai University,Nanjing 210098,China 3 Institute of Geology and Geophysics,Chinese Academy of Science,Beijing 100018,China 2007Acta Geologica Sinica(English Edition)2007,81,4:5
163D building modeling,organization and application in digital city system显示文摘The real world is a three-dimensional(3D)space requiring that 3D geospatial information applications be developed in alignment with the observer’s visual and perceptive habits.Particularly,3D building model data are required in a wide range of areas such as urban planning,environmental protection,real estate management and emergency response.At the same time,the development of Web service[LU1]technologies allows the possibility of the widely distributed 3D geospatial data on the web.3D city building model with its related information is an important part in the construction of a digital city system,and has become a staple resource on the web nowadays.In view of the hierarchical representation of a 3D building model,an abstract of a 3D building model based on structure details is studied,and a novel representation approach named 3D transparent building hierarchical model is presented in this paper.This approach fully uses both the existing 3D modeling technologies and CAD constructing mapping data.By the spatial relationship description,structural components inside a building can be represented and integrated as hierarchical models in a unified 3D space.In addition,based on the characteristics of the 3D building model data,a service-oriented architecture and Web service technologies for 3D city building models are discussed.The aim of the approach is that 3D city building models can be used as a kind of data resource service on the web,and can also exist independently in various different web applications.YANG Xue 1,WENG JingNong 1,2,XIA YuBin 2,WU Lun 3 & SUI ZhengWei 3 1 College of Software,Beihang University,Beijing 100191,China 2 College of Computer,Beihang University,Beijing 100191,China 3 Institute of Remote Sensing and GIS,Peking University,Beijing 100871,China 2010Science China(Technological Sciences)2010,53,S1:4
17Systematic study of survival probability of excited superheavy nuclei显示文摘The stability of excited superheavy nuclei (SHN) with 100 Z 134 against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. The present calculations consistently take the neutron separation energies and shell correction energies from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z = 115 and N = 179. It turns out that this island of stability persists for excited SHN in the sense that the calculated survival probabilities in the 1n-channel of excited SHN at the optimal excitation energy are maximized around Z = 115 and N = 179. This indicates that the survival probability in the 1n-channel is mainly determined by the nuclear shell effects.XIA ChengJun1, SUN BaoXi1, ZHAO EnGuang2,3 & ZHOU ShanGui2,3 1College of Applied Sciences, Beijing University of Technology, Beijing 100124, China 2Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China 3Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, China 2011Science China(Physics,Mechanics & Astronomy)2011,54,S1:4
18Prokaryotical expression of structural and non-structural proteins of hepatitis G virus显示文摘AIM To study the epitope distribution of hepatitis G virus (HGV) and to seek for the potential recombinant antigens for the development of HGV diagnositic reagents.METHODS Fourteen clones encompassing HGV gene fragments from core to NS3 and NS5 were constructed using prokaryotic expression vector pRSET and (or)pGEX. and expressed in E. coli. Western blotting and ELISA were used to detect the immunoreactivity of these recombinant proteins.``RESULTS One clone with HGV fragment from core to El(Gl). one from E2 (G31), three from NS3 (G6, G61, G7),one from NS5B (G821) and one chimeric fragment from NS3and NS5B (G61 821) could be expressed well and showed obvious immunoreactivity by Western blotting.One clone with I-KGV framment from NS5B (G82) was also well expressed, but could not show immunoreactivity by Western blotting. No obvious expression was found in the other six clones. All the expressed recombinant proteins were in inclusion body form, except the protein G61 which could be expressed in soluble form. Further purified recombinant proteins Gl, G,31, G61, G821 and G61 821were detected in indirected ELISA as coating antigen respectively. Only recombinant Gl could still show immunoreactivity, and the other four recombinant proteins failed to react to the HGV antibody positive sera.Western blotting results indicated that the immunoactivity of these four recombinant proteins were lost during purification.``CONCLUSION Core to El, E2. NS3 and NS5 fragment of HGV contain antigenic epitopes, which could be produced in prokaryotically expressed recombinant proteins. A high. yield recombinant protein (Gl) located in HGV core to E1 could remain its epitope after purification, which showed the potential that G1 could be used as a coating antigen to develop an ELISA kit for HGV specific antibody diagnosis.Ning-Shao Xia~1 Hai-Jie Yang~1 Jun Zhang~1 Chang-Qing Lin~1 Ying-Bin Wang~1 Juan Wang~1 Mei-Yun Zhan~2 MH Ng~3 1 Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering,Xiamen University,Xiamen 361005,Fujian Province,China2 Institute of Virology,Chinese Academy of Preventive Medicine Beijing 100052,China3 Department of Microbiology,Hoog Kong University,Hongkong,China 2001World Journal of Gastroenterology2001,7,5:4
19Single crystal β-Ga_2O_3: Cr grown by floating zone technique and its optical properties显示文摘β-Ga2O3: Cr single crystals were grown by floating zone technique. Absorption spectra and fluorescence spectra were measured at room temperature. The values of field splitting parameter Dq and Racah parameter B were obtained by the peak values of absorption spectra. The value 10Dq/B=23.14 manifests that in β-Ga2O3 crystals Cr3+ ions are influenced by low energy crystal field. After high temperature annealing in air, the Cr3+ intrinsic emission was enhanced and the green lumines-cence disappeared. The strong and broad 691 nm emission was obtained at 420 nm excitation due to the electron transition occurred from 4T2 to 4A2. The studies manifest that the β-Ga2O3 crystals have the potential application for tunable laser.ZHANG JunGang1, 2, LI Bin3, XIA ChangTai1, XU Jun1, DENG Qun4, XU XiaoDong1, WU Feng1, XU WuSheng4, SHI HongSheng4, PEI GuangQing1, 2 & WU YongQing1,2 1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China 2 Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 3 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China 4 GE (China) Research and Development Center Co. Ltd., Shanghai 201203, China 2007Science China(Technological Sciences)2007,50,1:4
20Theoretical studies on Ru(fppz)_2(CO)L (L=N-heterocyclic ligand):Electronic structure,absorption,phosphorescence,and solvatochromism显示文摘A series of ruthenium(II) complexes Ru(fppz)2(CO)L [fppz = 3-trifluoromethyl-5(2-pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2), 4-cyanopyridine (3)] were designed and investigated theo-retically to explore their electronic structures, absorption, and emissions as well as the solvatochrom-ism. The singlet ground state and triplet excited state geometries were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO of 1-3 is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2 is dominantly contributed by π*(fppz) orbital, but that of 3 is con-tributed by π*(L). Absorption and phosphorescence in vacuo, C6H12, and CH3CN media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2 at 387 and 391 nm is attributed to {[dyz(Ru) + π(fppz)] → [π*(fppz)]} transition, but that of 3 at 479 nm is assigned to {[dyz(Ru) + π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2 at 436 and 438 nm originates from 3{[dyz(Ru) + π(fppz)] [π*(fppz)]} excited state, while that of 3 at 606 nm is from 3{[dyz(Ru) + π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2 does not have solvatochromism, but that of 3 at 606 nm (vacuo), 584 nm (C6H12), and 541 nm (CH3CN) is strongly dependent on the solvent polarity, so introducing elec-tron-withdrawing group on ligand L will induce remarkable solvatochromism.LIU Tao1, ZHOU Xin1, BAI FuQuan1, ZHANG JianPo1, XIA BaoHui1,2, PAN QingJiang3 & ZHANG HongXing1 1 State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China 2 College of Chemistry, Jilin University, Changchun 130023, China 3 Laboratory of Physical Chemistry, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China 2008Science China Chemistry2008,51,12:4
返回顶部 每页显示:
共2页 首页 上一页 第1页 下一页 末页 /2 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费