检索结果-南通市图书馆

Monitoring Dynamic Change of Land Cover Based on SVM and Satellite Images in Hanoi,Vietnam

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural sciences 2010年第4期15卷 355-362页

作者： ZHAO Jinling1.2. LIU Chuang1. 3 1. {1. of Geographic {1. and Natural {2. Research, Chinese Academy of {1., beijing 1.01.1. China 2. Graduate University of Chinese Academy of {1., beijing 1.0049, China 3. College of {2. Science and Technology, beijing Normal University, beijing 1.0875, China institute of Geographic {1. and Natural {2. Research Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of sciences Beijing China College of resources Science and Technology Beijing Normal University Beijing China

An integral method,combining support vector ma-chine (SVM) with remote-sensing analysis techniques,was ex-plored to monitor Hanoi’s dynamic change of land cover. The landsat thematic mapper (TM) image in 1.93,the enhanced the-matic mapper plus (ETM+) image in 2.00,and the image with the charge-coupled device camera (CCD) on the China-Brazil earth {1. satellite (CBERS) in 2.08 were used. Six land-cover types,including built-up areas,woodland,cropland,sand,water body and unused land,were identified. The detected results showed visually the rapid urban expansion as well as land-cover change of Hanoi from 1.93 to 2.08. There were 1.0}637.54 hm2.cropland de-creased between 1.93 and 2.00,and 8 2.7.6 hm2.cropland de-creased between 2.00 and 2.08. Compared with cropland,wood-land firstly decreased and then increased,and the other types did not change significantly. The results indicate that CBERS dataset has the application potential in world {1. researches.

关键词： land cover the China-Brazil earth resources satellite (CBERS) support vector machine (SVM) change detection

Petrogenesis and dating of the Kangding complex,Sichuan Province

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2005年第5期48卷 622-634页

作者： CHEN Yuelong 1., LUO Zhaohua 1., ZHAO Junxiang, LI Zhihong, ZHANG Hongfei & SONG Biao 3 1. Faculty of Earth sciences and Natural {1., China University of Geosciences, beijing 1.0083, China 2. Faculty of Earth sciences, China University of Geosciences, Wuhan 430074, China 3. beijing SHRIMP Center, institute of Geology, Chinese Academy of Geological sciences, beijing 1.0037, China 1. Faculty of Earth sciences and Natural {1. China University of Geosciences 100083 Beijing China 2. Faculty of Earth {1. China University of Geosciences 430074 Wuhan China 3. beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences 100037 Beijing China

An analysis of major and trace element geochemistry and SHRIMP U-Pb zircon dating of mafic, intermediate, and felsic rocks from the Mianning metamorphic complex of Si- chuan Province was conducted. One of our conclusions is that a majority of the zircons crystal- lized between 72. and 773 Ma in a magmatic regime. The complexes contain early to late Pa- leo-proterozoic relict zircons from ancient continental crust. The oldest age, 2.68 Ma, may rep- resent the basement of the Yangtze block. Overgrowth zircon rims and palingenetic zircons have been observed and dated, and are believed to have formed after crystallization, during Paleozoic and Mesozoic metamorphic-anatexis. We also conclude that depletion of Nb, Ta, HREE, in a spider-diagram normalized to primitive mantle and calc-alkaline association, implies that they formed in island-arc or under-plating settings.

关键词： Kangding complex, zircons, SHRIMP, tectonic setting.

Edaphic factors determining variation of two ecotypes of Leymus chinensis in North China

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第11期16卷 1150-1155页

作者： ZHOU Chan~1.and YANG Yunfei~2.*(1. MOE Key Laboratory of Environmental Change and Natural Disasters, College of {1. Science and Technology, {1. Normal University, {1. 1.0875, China 2. Key Laboratory of Vegetation Ecology, Ministry of Education, institute of Grassland Science, Northeast Normal University, Changchun 1.002., China) [a]MOE Key Laboratory of Environmental Change and Natural Disasters College of Resources Science and Technology Beijing Normal University Beijing China [b]Key Laboratory of Vegetation Ecology Ministry of Education Institute of Grassland Science Northeast Normal University Changchun China

To identify ecotypic variation of L. chinensis, the physiological characteristics and environmental factors were measured and assessed for grey-green and yellow-green ecotypes of L. chinensis grown in the salt-alkalized and aeolian sandy soils. Although both ecotypes presented a similar salt-alkaline tolerance under the experimental conditions, they differed in several aspects. The L. chinensis grown in the aeolian sandy soils had higher water potential and chlorophyll content and lower proline content in their leaves than those grown in the salt-alkalized habitat, and the grey-green ecotype of L. chinensis in both types of soils had higher water potential, chlorophyll and proline contents than the yellow-green ecotype. Besides, grey-green ecotypes had higher salt-alkaline tolerance than the yellow-green ecotype. The stepwise regression analysis showed that soil conductance and pH value were the main ecological factors affecting the physiology of L. chinensis. From the natural distribution of the two ecotypes, we considered that salt-alkaline in the soils is the leading factor in determining ecotypic variation of L. chinensis. The two ecotypes were first named grey-green and yellow-green ecotypes respectively.

关键词： L.chinensis ecotype adaptability variation ecological factor salt-alkaline in soil.

The characteristics of chert from micro-disseminated gold deposits and their origin significance in southwestern Guizhou, China

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 Science Bulletin 1999年第S2期44卷 20-21页

作者： LIU Jiajun~1. LIU Congqiang~1. LIU Jianming~2.and GU Tuan~1.1. {1. of Geochemistry, Chinese Academy of {1., Guiyang 550002. China 2. The Reseatrch Center of Mineral {2. Exploration, Chinese Academy of {1., beijing 1.01.1. China institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Research Center of Mineral resources Exploration Chinese Academy of Sciences Beijing 100101 China

THE southwestern Guizhou Province has been acknowledged as one of the most important and potentialgold producing areas in the People’ s Republic of China and has attracted world-wide attention since thediscovery of a series of sediment-hosted micro-disseminated gold deposits in the last twenty years. Chertwidely occurs in the gold deposits. Study on geology and geochemistry of the chert may be important for abetter understanding of the forming condition and process of gold. 1.Characteristics of chert THE cherts are characterized by bedded, massived, pseudobrecciated and nodular structures, occurring insynsedimentary fault. The thickness of a chert bed generally varies from several meters to less than 2.meters, with the maximum up to about 70 meters. Host elements are simple and concentrated in thecherts. The SiO2./sub> concentration of the cherts varies from 86.4 % to 95.64 %, 91.95% on average

关键词： chert micro-disseminated gold deposits Guizhou.

Sandy desertification trend in western Northeast China Plain in the past 1. years

在线全文

学校读者我要写书评

暂无评论

Journal of geographical {1. 2001年第2期11卷 179-186页

作者： LI Bao-lin~1.2. ZHOU Cheng-hu~1.(1. LREIS, {1. of Geographic {1. and Natural {2. Research, CAS, beijing 1.01.1. China 2. {1. of Remote Sensing Application, CAS, beijing 1.01.1. China) institute of Remote Sensing Application CAS LREIS Institute of Geographic Sciences and Natural Resources Research CAS LREIS Institute of Geographic Sciences and Natural Resources Research CAS

The west sandy land of the Northeast China Plain is located in the eastern huge sandy belt of mid-latitude in Eurasia and the eastern fringe of desertified land with best bio-climatic conditions in China. With rapid economic development, the deterioration of eco-environment has occurred and the desertification becomes very obvious. The first part of this paper studies the regional differences of landscape patterns and explores the regional differences of desertification. The second part aims to reveal the dynamics of desertification in the 1.90s by using NOAA/AVHRR data and thematic data in GIS database. This work lays a scientific basis for the rehabilitation and development of the sandy lands.

关键词： west sandy land in Northeast China Plain landscape pattern regional difference remote sensing monitoring dynamic change

Re-Os age for molybdenite from the Gangdese porphyry copper belt on Tibetan plateau: Implication for geody- namic setting and duration of the Cu mineralization

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2004年第3期47卷 221-231页

作者： HOU Zengqian1. QU Xiaoming1. WANG Shuxian2. DU Andao2. GAO Yongfeng3 & HUANG Wei4 1. institute of Mineral {1., Chinese Academy of Geological {2., beijing 1.0037, China 2. National Center of Geoanalysis, Chinese Academy of Geological {2., beijing 1.0037, China 3. Shijiazhuang College of Economy, Shijiazhuang 056000, China 4. Xizang Bureau of Geology and Mineral {1., Lhasa 850000, China Chinese Acad Geol Sci Inst Mineral Resources Beijing 100037 Peoples R China Chinese Acad Geol Sci Natl Ctr Geoanal Beijing 100037 Peoples R China Shijiazhuang Coll Econ Shijiazhuang 056000 Peoples R China Xizang Bur Geol & Mineral resources Lhasa 850000 Peoples R China

The Gangdese porphyry copper belt consists of one large and five middle-small deposits in addition to dozens of ore-bearing porphyry bodies. The belt trends 350 km long along the EW-striking Gangdese batholith, and locally occurs as a string of beads extending about 50 km within the SN-trending rifting zones (grabens) on the Tibetan plateau. Monzonitic granite- porphyry and quartz monzonitic porphyry, as dominant host rocks, are shoshonitic and potassic calc-alkaline. Available dating data indicate that the ages of the shallow-level emplacement for these porphyries vary from 1. Ma to 1. Ma, which are identical to that of associated potassic calc-alkaline volcanic rocks (1.—1. Ma) and mafic dykes (1.—1. Ma). The timing and duration of Cu mineralization events are constrained by Re-Os ages for molybdenites from three porphyry copper deposits in the Gangdese porphyry copper belt. Five molybdenite samples from the Nanmu deposit yielded an 1.7Re-1.7Os isochron with a highly pre-cise age of (1..76?.2.) Ma; six molybdenites from the Chongjiang deposit gave an isochron age of (1..04?.1.) Ma. Re-Os model ages for two molybdenite samples from Lakang抏 deposit vary from 1..5 Ma to 1..6 Ma, which are basically identical to isochron ages mentioned above. All the thirteen samples from these three deposits yielded a linear array in the isochron diagram with a higher correlation coefficient of 0.9971. and an isochron age of (1..39?.2.) Ma (1. error), suggesting an coeval event of the Cu mineralization and a shared source of ore materials for the Gangdese porphyry copper belt. Compared with the longer-lived felsic magmatic-hydrothermal system, the Cu mineralization is a relatively short event with duration of about 0.5 Ma, and usu-ally occurs in the later-stage of the complicate magmatic system. The emplacement age of the Gangdese porphyries indicates that they intruded after the rapid rising of the Gangdese Mountains at 2.—2. Ma, and formed in a post-collision crustal ex-tension env

关键词： porphyry copper deposit, Re-Os age, Gangdese, Tibetan plateau.

Ecological hydraulic radius model to calculate instream flow requirements for transporting sediment in the western water transfer region

在线全文

学校读者我要写书评

暂无评论

Science China(Technological sciences) 2009年第11期52卷 3401-3405页

作者： MEN BaoHui1 & LIU ChangMing2.1 Renewable Energy institute, North China Electric Power University, {1. 102.06, China 2.Key Laboratory of Water Cycle and Related Land Surface Process, institute of geographical sciences and Natural resources Research, Chinese Academy of sciences, {1. 1.01.1. China 1. Renewable Energy institute North China Electric Power University Beijing 102206 China 2. Key Laboratory of Water Cycle and Related Land Surface Process Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Transporting sediment is a natural function of the river. To maintain the normal evolution of the river certain amount of water flow is required, which is called the instream flow requirements for transporting sediment (IFRTS). We defined the permitting flow velocity by the conception of IFRTS, and also put forward the ecological hydraulic radius model (EHRM) to estimate IFRTS. The calculating process of EHRM is explained by the example of Daofu Hydrological Station on Xianshui branch of Yalong River in the west line first-stage construction of South-North Water Transfer Project. The result shows that the IFRTS occupied 2..7%―59.5% of annual mean discharge in flood season, the average of IFRTS was about 1.0.2.m3/s during 1.66―1.87, it is close to the IFRTS 90 m3/s calculated by IFRTS conception. Hence, it is feasible to use EHRM to calculate IFRTS.

关键词： ecological hydraulic radius model (EHRM) instream flow requirements for transporting sediment (IFRTS) permitting flow velocity ecological hydraulic radius for transporting sediment

CH_4 uptake flux of Leymus chinensis steppe during rapid growth season in Inner Mongolia,China

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2010年第7期53卷 977-983页

作者： GENG YuanBo1. LUO GuangQiang1.2.& YUAN GuoFu1.1.{1. of Geographic {1. and Natural {2. Research, Chinese Academy of {1., beijing 1.01.1. China 2.Graduate University of Chinese Academy of {1., beijing 1.0049, China 1. institute of Geographic {1. and Natural {2. Research Chinese Academy of Sciences Beijing 100101 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The influence of near ground atmosphere CH4 concentration, soil water content, soil Eh, plants, soil temperature, and pH on CH4 uptake flux of Leymus chinensis steppe during rapid growth season was studied using field in-situ measurement in Xilin River basin of Inner Mongolia, China. The results showed that CH4 uptake flux was positively correlated with near ground atmosphere CH4 concentration and soil Eh but negatively correlated with soil water content. Precipitation may decrease the CH4 flux by increasing the soil water content. The average fluxes of three treatments during the observation period were 1.52.(natural conditions, 1.51.(aboveground plants were excluded), and 2.00 mg m?2.d?1.(all plants were removed), respectively. The difference between the CH4 flux of natural condition treatment and that of removing aboveground plants treatment is small, whereas the flux of removing all plants treatment is larger than the other two treatments. This means that the contribution of aboveground plants to CH4 uptake flux is smaller than that of roots or roots-removing process. CH4 uptake flux is not sensitive to soil temperature and the narrow-ranged soil pH (6.36–7.86). The Leymus chinensis steppe acts as a sink for CH4, and thus more studies should be focused on its affecting factors and related mechanisms.

关键词： CH4 uptake flux Leymus chinensis steppe affecting factors static opaque chamber/gas chromatography method

Node ordinal encoded genetic algorithm for the optimal allocation of water resources

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第5期15卷 448-452页

作者： YANG Xiaohua1.*, YANG Zhifeng 1.2. SHEN Zhenyao1.and LI Jianqiang3(1. State Key Laboratory of Water Environment Simulation, School of Environment, {1. Normal University, {1. 1.0875, China 2. Key Laboratory for Water and Sediment {2. Ministry of Education, School of Environment, {1. Normal University, {1. 1.0875, China 3. Water resources and Hydropower Planning and Design General institute, MWR, {1. 1.001., China) State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education School of Environment Beijing Normal University Beijing 100875 China Water resources and Hydropower Planning and Design General {1. MWR Beijing 100011 China

A new method, node ordinal encoded genetic algorithm (NOEGA), is proposed for solving water resources optimal allocation problems, in which the capacity of water resources is split into a number of smaller parts so that successive operations can be overlapped. Our objective is to maximize the whole benefit function. To overcome the “dimensionality and algorithm complexity curse” while searching for solutions and looking for an optimal solution, the operations of one-point crossover operator, gene exchange operator, gene random operator, gene shift operator and node ordinal strings are established. It is proved to be an effective optimal method in searching for global solutions. The NOEGA does not need a diversity of initial population, and it does not have the problem of immature convergence. The results of two cases show that using NOEGA to solve the optimal allocation model is very efficient and robust. In addition, the algorithm complexity of NOEGA is discussed.

关键词： water resources optimal allocation node ordinal code genetic algorithm.