检索结果-南通市图书馆

Spatial distribution of wind erosion and its driving factors in 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

Journal of geographical sciences 2001年第2期11卷 127-139页

作者： ZHANG Guo-ping~1, ZHANG Zeng-xiang~1, liu Ji-yuan~2.(1. institute of Remote Sensing Application, CAS,{2.,{2. 2. institute of geographic sciences and natural resources research, CAS,{2.,{2.) institute of Remote Sensing Application CAS institute of geographic {2. and {3. resources research CAS

Based on remote sensing and geographic information system, the spatial distribution of nation-wide wind erosion is studied, and the 1∶100 000 national map of soil erosion by wind in china is made. Wind speed, soil dryness,NDVI, soil texture and the slope of land surface are the key factors to wind erosion. The relations between wind erosion and each factor are discussed. The method of principal component is used to pick up the information included in the five factors, and the wind erosion dynamic index (WEDI) is established. Its comparison with theRS/GIS derived data shows thatWEDI can reflect the potential capacity of soil erosion by wind. The dynamic process of the wind erosion is studied to reveal the distribution of the most intense wind erosion regions and the dominant factors in these regions. All these studies may greatly help the mitigation of wind erosion of soil.

关键词： remote sensing geographic information system wind erosion of soil desertification control in china WEDI

Water resources optimization and eco-environmental protection in Qaidam Basin

在线全文

学校读者我要写书评

暂无评论

Journal of geographical sciences 2001年第2期11卷 231-238页

作者： FANG Chuang-lin~1, BAO Chao~2.(1. institute of geographic {2. and {3. resources research, CAS, beijing 100101, china 2. Dept. of Geography, Peking University, beijing 100871, china) institute of geographic {2. and {3. resources research CAS Dept. of Geography Peking University

In order to realize sustainable development of the arid area of Northwest china, rational water resources exploitation and optimization are primary prerequisites. Based on the essential principle of sustainable development, this paper puts forward a general idea on water resources optimization and eco-environmental protection in Qaidam Basin, and identifies the competitive multiple targets of water resources optimization. By some qualitative methods such as Input-output Model & AHP Model and some quantitative methods such as System Dynamics Model & Produce Function Model, some standard plans of water resources optimization come into being. According to the Multiple Targets Decision by the Closest Value Model, the best plan of water resources optimization, eco-environmental protection and sustainable development in Qaidam Basin is finally decided.

关键词： water resources optimization Multiple Targets Decision by the Closest Value Model eco-environmental protection Qaidam Basin

Digital image analysis of palaeoenvironmental records and applications

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第23期47卷 1957-1963,2025-2026页

作者： SUN Donghuai1,2. liu Yu2.& TAN Ming3.. South{3. Sea {2. of Oceanology,{2.. Guangzhou 5103.1,{3. 2. State Key Laboratory of Loess and Quaternary Geology, Earth Environmental {2.,{2., Xi’an 710075,{3. 3. {2. of Geology and Geophysics,{2., {13. 10002.,{3. South china Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China State Key Laboratory of Loess and Quaternary Geology Earth Environmental Institute Chinese Academy of Sciences Xi’an China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

Environmental change signals in geological or biological records are commonly reflected on their reflecting or transmitting images. These environmental signals can be extracted through digital image analysis. The analysis principle involves section line selection, color value reading and calculating environmental proxy index along the section lines, layer identification, auto-chronology and investigation of structure evolution of growth bands. On detailed illustrations of the image technique, this note provides image analyzing procedures of coral, tree-ring and stalagmite records. The environmental implications of the proxy index from image analysis are accordingly given through application demonstration of the image technique.

关键词： digital image environmental records.

Variations of near-surface atmospheric CO_(2.and H_(2.O concentrations during summer on Muztagata

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第1期49卷 18-26页

作者： XU Baiqing1,2. YAO Tandong1,2. LU Anxin2. GUO Xuejun, {3. Xianqin2.& LI Zhen2.1. Laboratory of Environment and Process on Tibetan Plateau, institute of Tibetan Plateau {2.,{2., {3. 100085, china 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering {2. institute and institute of Tibetan Plateau {2.,{2. and chinese {12. of Meteorological sciences, china Meteorological Administration, Lanzhou 73.000, china 1. Laboratory of Environment and Process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Key Laboratory of Cryosphere and Environment Jointly Established by Cold and Arid Regions Environmental and Engineering Research Institute and Institute of Tibetan Plateau Research Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences China Meteorological Administration Lanzhou 730000 China

Expeditions during the summers of 2.02.and 2.03.implemented continuous monitoring of near-surface (2.m height) atmospheric CO2.and H2. concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO2.concentrations (of about 5 μmol·mol?1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO2.concentrations occur between 02.3.―05:3. AM (local time) and the minimum levels occur between 12.00―15:3. PM. The atmospheric CO2.concentrations in the summer of 2.02.were around 5 μmol·mol?1 lower than those during the same period of 2.03. whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H2. content in 2.03.was much lower than that in 2.02.and there exists a striking negative correlation between CO2.and H2. con-centrations. We therefore suggest that the near-surface atmospheric CO2.concentration is affected not only by photosynthesis and respiration, but also by the air H2. content in the glaciated region around Muztagata.

关键词： atmospheric CO2 and H2. concentration, continuous monitoring, glaciation region, Muztagata.

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2. TANG Rupei1, liu Minghua2.& XI Fu1 1. State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, {3. of Chemistry,{2., {2. 100080,{3. 2. CAS Key Laboratory of Colloid and Interface Science, {3. of Chemistry,{2., {2. 100080,{3. 1. State Key Laboratory of Polymer Physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China 2. CAS Key Laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China

Diblock copolymer of PMMA2.1-b-PEO114 and triblock copolymer of PMMA12.-b- PEO2.7-b-PMMA12. were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.

GIAHS Project and Its Implementation in china

在线全文

学校读者我要写书评

暂无评论

Journal of resources and Ecology 2010年第1期1卷 94-96页

作者： MIN Qingwen~1,SUN Yehong~(1,2. and SHI Yuanyuan~1 1.institute of geographic {2. and {3. resources research,CAS,beijing 100101,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 1. institute of geographic {2. and {3. resources research CAS Beijing 100101 China 2. Graduate University of chinese academy of sciences Beijing 100049 China

GIAHS Project and Concept In 2.02.Food and Agriculture Organization of the United Nations(hereafter FAO)started an initiative for the conservation and adaptive management of Globally Important Agricultural Heritage Sy... 详细信息

关键词： GIAHS Project and Its Implementation in china Project

SEDIMENT YIELD MODELING FOR SINGLE STORM EVENTS BASED ON HEAVY-DISCHARGE STAGE CHARACTERIZED BY STABLE SEDIMENT CONCENTRATION

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment research 2007年第3期22卷 208-217页

作者： Mingguo ZHENG1, Qiangguo CAI2, and Qinjuan CHENG3.1Assistant professor, Key Laboratory of Water Cycle and Related Land Surface Processes, institute of geographic {2. & {3. resources research, CAS, beijing 100101,china. 2 Professor, Key Laboratory of Water Cycle and Related Land Surface Processes, institute of geographic {2. & {3. resources research, CAS, beijing 100101,china. 3.Doctoral candidate, Key Laboratory of Water Cycle and Related Land Surface Processes, institute of geographic {2. & {3. resources research, CAS, beijing 100101,china. Graduate School of the{2.}, {2.} 10003.,{2.}. chinese Acad Sci Inst Geog Sci & Nat Resources Res Key Lab Water Cycle & Related Land Surface Proc Beijing 100101 Peoples R China

The relation between runoff volume and sediment yield for individual events in a given watershed receives little attention compared to the relation between water discharge and sediment yield, though it may underlie the event-based sediment-yield model for large-size watershed. The data observed at 12.experimental subwatersheds in the Dalihe river watershed in hilly areas of Loess Plateau, North china, was selected to develop and validate the relation. The peak flow is often considered as an important factor affecting event sediment yield. However, in the study areas, sediment concentration remains relatively constant when water discharge exceeds a certain critical value, implying that the heavier flow is not accompanied with the higher sediment transport capacity. Hence, only the runoff volume factor was considered in the sediment-yield model. As both the total sediment and runoff discharge were largely produced during the heavy-discharge stage, and the sediment concentration was negligibly variable during this stage, a proportional function can be used to model the relation between event runoff volume and sediment yield for a given subwatershed. The applicability of this model at larger spatial scales was also discussed, and it was found that for the Yaoxinzhuang station at the Puhe River basin, which controls a drainage area of 2.64km2. a directly proportional relation between event runoff volume and sediment yield may also exist.

关键词： Sediment yield Peak flow Flow-sediment relation Loess Plateau

Problems and countermeasures of sustainable development in Fujian Province in the new century

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of geographical sciences 2000年第4期10卷 20-27页

作者： ZHOU Guo-min, MAO Han-ying, YANG Yan-feng (institute of geographic {2. and {3. resources research, chinese academy of sciences, beijing 100101, china) 中科院地理科学与资源所北京

Fujian province is one of the coastal provinces with rapid economic growth after the reform and opening to the outside world. Being one of the two basic strategies of china in the new era, sustainable development plays a directive role in the coordinated development of socio-economy, natural {2. and ecology of Fujian. This paper analyses some important issues influencing sustainable development in Fujian in the next 2. years, such as the sustainable development of economy, investment environment improving and further opening to the outside, urbanization and coordinated development of city system, rational exploitation of natural {2., environmental conservation and ecological rehabilitation, and narrowing intraprovincial gap. Corresponding countermeasures are put forward.

关键词： Fujian province sustainable development problems and countermeasures

A preliminary knowledge-driven prediction model of snail distribution in the Poyang Lake region

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2008年第1期53卷 115-123页

作者： ZHAO An1,2.3.& BAO ShuMing1 1 The Key Lab of Poyang Lake Ecological Environment and Resource Development, Jiangxi Normal University, Nanchang 3.002., china 2.institute of {2. {3. and resources research, chinese academy of sciences, beijing 100101, china 3.School of Geography and Environmental {3., Jiangxi Normal University, Nanchang 3.002., china The Key Lab of Poyang Lake Ecological Environment and Resource Development Jiangxi Normal University Nanchang China institute of geographic {2. and {3. research Chinese Academy of Sciences Beijing China School of Geography and Environmental sciences Jiangxi Normal University Nanchang China

Present monitoring and prediction of schistosomiasis’s intermediate parasite, snail, are based on re-mote sensing image’s spectral signatures, and the calculation result is in fact an incom-plete-constraints solution. TM image of the Poyang Lake region on October 3., 2.05 was combined with GIS thematic data (DEM, boundary of the Poyang Lake, vegetation, soil and land use) to make a prediction on snail spatial distribution in the region by remote sensing, geo-informatics and knowl-edge-driven modeling according to mechanism of snail occurrence. Result shows that with change of overall fuzzy membership of snail occurrence from high to low, snail occurrence of the snail samples of validation group goes up to 81% within 10% high fuzzy membership range, denoting high efficiency of the model in predicting snail occurrence.

关键词：鄱阳湖区域蜗牛分布模糊分类血吸虫病