检索结果-南通市图书馆

Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau

Science China Earth Sciences 2006年第9期49卷 991-1001页

作者： WU Yanhong1. WANG Sumin1. HOU Xinhua1.3 1. Key Laboratory of Lake Sedimentation and Environment, Nanjing Institute of Geography and Limnology, chinese {1. of Sciences, Nanjing 21.008, China 2. Institute of Tibetan Plateau Research, chinese {1. of Sciences, Beijing 1.085, China 3. Graduate University of chinese {1. of Sciences, Beijing 1.0039, China 1. Key Laboratory of Lake Sedimentation and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 2. Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 10085 China 3. Graduate University of chinese {1. of Sciences Beijing 100039 China

Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. Radioactive-nuclides such as 1.C, 21.Pb and 1.7Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 1.C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 21.Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 1.C dating is stronger. Based on the analysis on results of 1.C, 21.Pb and 1.7Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 1.C calendar ages, and establish the time sequence for cores CE-1.and CE-2 with result of 21.Pb CRS model for the upper 35 cm and re-calculated 1.C calendar age for sediments bellow 35 cm. Since 1.00 cal. a BP, sedimentation inter-rupted for more than 1.00 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.

关键词： 1.C, 21.Pb and 1.7Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan Plateau.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Size-dependent hydroxyl radicals generation induced by SiO_2 ultra-fine particles: The role of surface iron

引用

Science China Chemistry 2009年第7期52卷 1033-1041页

作者： SHANG Yu1. ZHU Tong1. LI Yi1.2 & ZHAO JinCai3 1.College of Environmental Sciences and Engineering, Peking University, Beijing 1.0871. China 2 chinese {1. of meteorological Sciences, Beijing 1.0871. China 3 Institute of Chemistry, chinese {1. of Sciences, Beijing 1.0871. China 1. College of Environmental Sciences and Engineering Peking University Beijing 100871 China 2. chinese {1. of meteorological Sciences Beijing 100871 China 3. Institute of Chemistry Chinese Academy of Sciences Beijing 100871 China

Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM1.). The ultra-fine fraction of PM1. has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 1., 1.0, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 1. nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.81., p1.. Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

关键词： ultra-fine particles nano-particles ·OH oxidative stress size-effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Growth characteristics and response to climate change of Larix Miller tree-ring in China

引用

Science China Earth Sciences 2010年第6期53卷 871-879页

作者： SUN Yu1.4, WANG LiLi1.2,3, CHEN Jin5, DUAN JianPing1.4, SHAO XueMei1.2 & CHEN KeLong6 1.Institute of Geographic Sciences and Natural Resources Research, chinese {1. of Sciences, Beijing 1.01.1. China 2 Institute of Tibetan Plateau Research, chinese {1. of Sciences, Beijing 1.0085, China 3 Institute of Desert and Meteorology, China meteorological Administration, Urumqi 830002, China 4 Graduate University of chinese {1. of Sciences, Beijing 1.0049, China 5 Institute of Vertebrate Paleontology and Paleoanthropology, chinese {1. of Sciences, Beijing 1.0044, China 6 School of Life and Geography Sciences, Qinghai Normal University, Xining 81.008, China 1. Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China3. Institute of Desert and Meteorology China Meteorological Administration Urumqi 830002 China5. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China6. School of Life and Geography Sciences Qinghai Normal University Xining 810008 China

As one of the earliest species used in dendrochronological studies, Larix responds sensitively to climate change. In this study, nine larch species and one variety from eleven sites were collected to study the growth characteristics of tree-ring width using dendrochronological methods. Ten residual tree-ring chronologies were developed to analyze their relationships with regional standardized anomaly series by Pearson’s correlation analysis. The results suggest that most of the chronologies had significantly positive correlations with the mean temperature and mean maximum temperature in May. The spring temperature evidently limited the radial growth of the larch species without precipitation control. The largest mean tree-ring width was found in Himalayan Larch in Jilong, whereas Master Larch in Si’er reflected the smallest mean value. Both species presented little climate information in this study. chinese, Potanin, and Tibetan larches are significantly correlated with climate change, implying a huge potential for climate history reconstruction. The elevation of the sampling sites appears to be an important condition for tree-ring growth of larches responding to climate factors.

关键词： Larix Miller tree-ring climate change mean temperature in May

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Architecture and application of integrated spatial information service platform for digital mine

引用

中国有色金属学会会刊：英文版 2011年第S3期21卷 706-711页

作者： ZHANG Jin1. XIAO Jie2 1. College of Mining, Taiyuan University of Technology, Taiyuan 030024, China 2. Institute of Geodesy and Geophysics, chinese {1. of Sciences, Wuhan 430077, China Taiyuan Univ Technol Coll Min Taiyuan 030024 Peoples R China chinese Acad Sci Inst Geodesy & Geophys Wuhan 430077 Peoples R China

Using enterprise GIS platform, spatial databases and modern information technology, building geo-spatial information service platform of digital mine which has the features of the data exchange service, enterprise GIS services, directory services, logging services, is key technology and application infrastructure for digital mine. Based on the support of geospatial information service platform of digital mine, the professional GIS application service adapter can be developed and the application supports related to mining application system can be realized. Using high-resolution satellite remote sensing data, the mine functional partition map and geographic grids can be divided, and the geographic grid parts, status and events of important features of the surface object were investigated and defined. The system architecture and technical characteristics of integrated spatial information service platform were analyzed firstly, which guarantee service ability of digital mine. The methods and applications of functional partition map for integrated management service platform were discussed which are the services scheme of digital mine. The application results indicated that digital mine upgrades and enhances the capability and range of mine surveying and mapping, and is of great significance for guarantee of efficient, green and intensive exploitation of mine.

关键词： platform architecture web services application services digital mine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mineralogy and crystal structure determination of Mg-fillowite

引用

Science China Earth Sciences 2005年第5期48卷 635-646页

作者： MA Zhesheng 1., SHI Nicheng 1.& YE Danian 2 1. China University of Geosciences, Beijing 1.0083, China 2. Institute of Geology, chinese {1. of Sciences, Beijing 1.0029, China 1. China University of Geosciences 100083 Beijing China 2. Institute of Geology Chinese Academy of Sciences 100029 Beijing China

Accurate crystal structure determination of complex phosphate Mg-fillowite ? Na2Ca(Mn4Mg2Fe)7[PO4]6 has been finished. Mg-fillowite occurs in muscovite-pegmatite in the Altay area, Xinjiang, China. It is of the trigonal lattice, with space group R-3, unit cell a=1.51.3(3) nm, c=4.31.1.2) nm, V=8.5736 nm3, Z = 1.. The R-factor of the determination accuracy is R (I > 2σ ( I )) = 0.0776. The cationic polyhedra consist of two kinds of structural units: compound col- umn and screw column. In three-dimensional space, they are linked with each other through corner sharing or edge sharing to build the entire structure. There are 45 atoms in an asymmetric unit and 720 atoms in a unit cell. In terms of types and connection manners of the coordination polyhedra, the degree of complicity is rarely seen in all mineral crystal structures. Study of such a structure is significant for the classification of phosphate and the building rule of coordination polyhedra in a complex crystal structure.

关键词： Mg-fillowite, complex phosphate, crystal structure, coordination polyhedron.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characteristics and geological significance of olivine xenocrysts in Cenozoic volcanic rocks from western Qinling

引用

Progress in Natural Science:Materials International 2006年第12期16卷 1300-1306页

作者： SU Benxun~ 1.2 **, ZHANG Hongfu~1. XIAO Yan~ 1.2 and ZHAO Xinmiao~ 1.2 (1. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, chinese {1. of Sciences, Beijing 1.0029, China 2. Graduate School of chinese {1. of Sciences, Beijing 1.0039, China) [a]State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China [b]Graduate School of chinese {1. of Sciences Beijing China

Cenozoic volcanic rocks from the Haoti, Dangchang County of the western Qinling Mountains, contain a few clearly-zoned olivines. These olivines are relatively big in grain sizes and usually have cracks or broken features. Their cores have similar compositions （Mg#=90.4-91.0） to those for the peridotitic xenoliths entrained in host volcanic rocks and their rims are close to the compositions of olivine phenocrysts （Mg#=85.5-81.9）. The CaO contents in these zoned olivines are lower than 0.1.. These features demonstrate that the clearly-zoned olivines are xenocrysts and disaggregated from mantle peridotites. The zoned texture was the result of the interaction between the olivine and host magma. Available data show that the volcanic rocks would have been derived from the mantle source metasomatized by subducted hydrathermally-altered oceanic crust. The formation of these Cenozoic volcanic rocks was perhaps related to the rapid uplift of the Tibetan Plateau.

关键词： Western Qinling Dangchang Haoti Cenozoic volcanic rocks olivine xenocrysts zoned texture.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese national clinical practice guidelines on prevention,diagnosis and treatment of early colorectal cancer

引用

chinese Medical Journal 2024年第17期137卷 2017-2039页

作者： Jingnan Li Hongwei Yao Yun Lu Shutian Zhang Zhongtao Zhang Society of Digestive Endoscopy of the chinese Medical Association Colorectal Surgery Group of the chinese Medical Association chinese Association of Gastroenterologist&Hepatologist National Clinical Research Center for Digestive Diseases chinese Medical Journal Clinical Practie Guideline Collaborative Department of Gastroenterology Peking Union Medical College HospitalChinese Academy of Medical SciencesPeking Union Medical CollegeBeijing 100730China Department of General Surgery Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseasesBeijing 100050China Department of General Surgery The Affiliated Hospital of Qingdao UniversityQingdaoShandong 266555China Department of Gastroenterology Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseaseBeijing 100050China 不详

Background:The incidence and mortality of colorectal cancer(CRC)in China are increasing in recent *** clarified pathogenesis and detectable precancerous lesions of CRC make it possible to prevent,screen,and diagnose CRC at an early *** the development of endoscopic and surgical techniques,the choice of treatment for early CRC is also worth further discussion,and accordingly,a standard follow-up program after treatment needs to be ***:This clinical practice guideline(CPG)was developed following the recommended process of the World Health Organization,adopting Grading of Recommendations Assessment,Development and Evaluation(GRADE)in assessing evidence quality,and using the Evidence to Decision framework to formulate clinical recommendations,thereby minimizing bias and increasing transparency of the CPG development *** used the Reporting Items for practice Guidelines in HealThcare(RIGHT)statement and Appraisal of Guidelines for Research and Evaluation II(AGREE II)as reporting and conduct guides to ensure the guideline’s completeness and ***:This CPG comprises 46 recommendations concerning prevention,screening,diagnosis,treatment,and surveillance of *** these recommendations,we have indicated protective and risk factors for CRC and made recommendations for *** proposed a suitable screening program for CRC based on the chinese *** also provided normative statements for the diagnosis,treatment,and surveillance of CRC based on existing clinical evidence and ***:The 46 recommendations in this CPG are formed with consideration for stakeholders’values and preferences,feasibility,and *** are generalizable to resource-limited settings with similar CRC epidemiology pattern as China.

关键词： Colorectal cancer Early detection of cancer Prevention Screening Diagnosis Treatment Follow-up Guideline

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Urban effects and summer thunderstorms in a tropical cyclone affected situation over Guangzhou city

引用

Science China Earth Sciences 2007年第12期50卷 1867-1876页

作者： MENG WeiGuang1.3,YAN JingHua1.& HU HaiBo2 1.Institute of Tropical and Marine Meteorology,chinese {1. Administration(CMA),Guangzhou 51.080,China 2 Institute of Urban Meteorology,CMA,Beijing 1.0089,China 3 State Key Laboratory of Severe Weather,chinese academy of {1. Sciences,Beijing 1.0081.China 1. Institute of Tropical and Marine Meteorology Chinese Meteorological Administration (CMA) Guangzhou 510080 China 3. State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China 2. Institute of Urban Meteorology CMA Beijing 100089 China

With data mainly from Guangzhou mesonet Automatic Weather Stations(AWS),Guangzhou Doppler Radar and satellite TBB data,characteristics and evolution of the urban heat island(UHI) over Guang-zhou City were analyzed in a tropical cyclone affected situation for early August *** particular,two thunderstorms occurring during this period respectively at the night of 4 August and in the afternoon of 7 August were investigated to study the relationships between the development of thunderstorms and the *** showed that two thunderstorms were associated with the UHI *** induced local air convergence and initiated the thunderstorm *** cases showed a general agreement in time and space for the locations of maximum UHI,convergence,convection,and *** was found to be more favorable to developing in time periods and locations with stronger intensity of *** also showed that,due to the urban effects,both thunderstorms got strengthened when moving over Guangzhou City,with maximum radar echoes observed right over the urban area and precipitation located within the *** these features reveal that two thunderstorms were urban-induced storms.

关键词： summer thunderstorms, urban heat islands (UHI), urban effects, tropical cyclone

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical experiments for the impacts of temperature and precipitation variation on the growth and development of winter wheat

引用

Journal of Environmental Sciences 1993年第2期5卷 194-200页

作者： Zhang YuAgrometeorological Research Center, {1. academy of meteorological Sciences, Beijing 1.0081. China Agrometeorological Research Center Chinese Academy of Meteorological Sciences Beijing 10081 China. China

The growth process of winter wheat was simulated by CERES-wheat model assuming the daily temperature increase -1. 0,1. 2℃ and daily precipitation increase -20, -1., -5, 0, 5, 1., and 20 percent, respectively. The case study site is Zhenjiang City of Jiangsu Province in the east China. Simulation results show that the impacts of temperature variation on winter wheat is stronger than that of precipitation. Climate warming would speed development rate and shorten phonological period. In general, the adverse effect of climate change on grain yield is greater than that of its beneficial effect, especially when the climate becoming cooler and dryer. The increase of temperature and decrease of precipitation would reduce the plant extractablc soil water content.

关键词： climate change winter wheat CERES-wheat model.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The onset and advance of the Asian summer monsoon

引用

Science Bulletin 2006年第1期51卷 80-88页

作者： Lü Junmei1.2,4, ZHANG Qingyun1. TAO Shiyan1.& JU Jianhua3 1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, chinese {1. of Sciences, Beijing 1.0029, China 2. Department of Atmospheric Sciences, Yunnan University, Kunming 650091. China 3. China meteorological Administration Training Centre, Beijing 1.0081. China 4. Graduate School of chinese {1. of Sciences, Beijing 1.0039, China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Department of Atmospheric Sciences Yunnan University Kunming 650091 China Graduate School of chinese {1. of Sciences Beijing 100039 China China meteorological Administration Training Centre Beijing 100081 China

Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for Environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South China Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.

关键词： Asian summer monsoon intraseasonal variability onset advance.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：