检索结果-南通市图书馆

Analytical method of Cr stable isotope and its application to water pollution survey

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第7期55卷 664-669页

High Cr(VI) concentration is a potential serious risk to environment and ecologic ***,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A new method of in-situ tracer technique by Cr isotopic analysis for quantitatively estimating Cr-contamination and its regional evolution in natural waters as well as a case application are reported in this *** on documented literatures,an experimental procedure for chemical separation and purification of Cr in water samples and its analytical method for Cr isotopic measurement by thermal ionization mass spectrometry(TIMS) are *** samples collected around a chemical factory in Hubei Province were analyzed by this *** samples showδ53Cr values ranging from-1.7‰to 7.3‰and an elevating trend with an increasing in distance from the sampling site to pollution source.A functional correlation following Rayleigh fractionation law was established between sample'sδ53Cr value and its extent of Cr *** study suggests that Cr isotopic analysis is an effective method to reveal the spatial distribution and its evolution trend of Cr contamination in the regional water *** is thus helpful to assessing the self-purifying ability of local water system according to Cr isotopic fractionation.

关键词：铬(VI) 水污染调查稳定同位素应用同位素分析供水系统演变趋势示踪技术

Risk analysis system of geo-hazard based on GIS technique

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2002年第3期12卷 371-376页

作者： ZHU Liangfeng, ZHANG Guirong, YIN Kunlong, ZHANG Liang (1. Faculty of Engineering, china University of Geosciences, Wuhan 430074, china 2. china Research institute of land resources and Economy, beijing 101149, china) Faculty of Engineering China University of Geosciences(Wuhan) Wuhan 430074 china Research institute of land resources and Economy 北京 101149

The socio-economic attribute of geo-hazard made us distinguish it from the traditional engineering geology study. It will get more social benefit from the analysis of the geo-hazard in the socio-economic attribute. The hazard and the vulnerability of the element controls the risk level of the regional geo-hazard. The risk analysis supported by GIS in geo-hazard study is one of the most important directions. Based on the author’s studies in recent years, a risk analysis system of regional geo-hazard (RiskAnly) has been developed on the basis of software MAPGIS. The paper introduces the train of system design, the structure and the workflow of RiskAnly. As a case study, the paper also deals with the risk zonation of the regional landslide hazard of china.

关键词： geo-hazard GIS risk analysis landslide

Human activity response and prevention strategies on soil and water loss in Sichuan Province

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2003年第z1期46卷 91-109页

作者： FANG Yiping & CHEN Guojie institute of Mountain Hazards and Environment, Chinese Academy of Sciences and ministry of Water resources, Chengdu 610041, china Chinese Acad Sci Inst Mt Hazards & Environm Chengdu 610041 Peoples R China Minist Water resources Chengdu 610041 Peoples R China

Ten major factors have been selected to judge the degree of disturbance from human activity and the corresponding relationship of the impact on soil and water loss in Sichuan Province. Correlation analysis has demonstrated that stock-carrying capacity, percentage of land reclamation, population density, GDP per capita, mineral modulus and percentage of forest coverage are the 6 most relevant human activity factors. The analysis on the degree of disturbance has shown that population pressure, excessive or unreasonable activities in development of resources and destructive behavior of humans are the main causes of soil and water loss. Consequently, solving the various problems in the negative activity of humans and regulating human behavior are the first tasks that should be tackled in the conservation of water and soil. In the new era, the prevention and rectification of soil and water loss are measures based on the foundation of the ecosystem, which is a kind of management strategy for sustainable development. The foundation of this method is made up of the system innovations and breakthroughs in terms of aims, philosophy, measures, and aspects of the prevention and rectification of soil and water loss, simultaneous advance from the conceptual, policy, spatial, technical and mode levels and system integration on the treatment strategies.

关键词： Sichuan, degree of disturbance, soil and water loss, system innovation.

Structural patterns of land types and optimal allocation of land use in Qinling Mountains

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2001年第1期11卷 99-109页

作者： LIU Yan-sui, DENG Xiang-zheng (institute of Geographic Sciences and Natural resources Research, CAS, beijing 100101, china) institute of Geographic Sciences and Natural resources Research CAS Beijing China

The case study based on Qinling Mountains in Shaanxi Province of china, in virtue of the information from TM image, classifies the land types and analyzes their spatial and temporal differential law, and puts forward three structural patterns of land types in mountainous areas, namely, spatial, quantitative and qualitative structures of mountainous land types. Furthermore, it has been noticed that the analysis of structural patterns can disclose the heterogeneity and orderliness of combination of land types, which can lay the theoretic foundation for comprehensively recognizing ecological characteristics and succession law of structure and function of land types. After the all-around comparative analysis, an optimal allocation of land use in Qinling Mountains has been put forward according to the principle of sustainable development and landscape ecology, which can lay the scientific foundation in practice for the structural adjustment and distribution optimization from the macro level to micro level.

关键词： land types succession of land types structural patterns optimal allocation Qinling Mountains

Simulating Hydrologic Changes with Climate Change Scenarios in the Haihe River Basin

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2005年第5期15卷 53-58页

作者： YUAN Fei 1,2, XIE Zheng-Hui1,* 2, LIU Qian1 and XIA Jun 3 1LASG, institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029 (china). 2 College of Water resources and Environment, Hohai University, Nanjing 210098 (china)3 institute of Geographical Science & Natural resources, Chinese Academy of Sciences, beijing 100101 (china) institute of Atmospheric Physics Chinese Academy of Sciences beijing 100029 （china）. 2 College of Water resources and Environment Hohai University Nanjing 210098 （china）3 institute of Geographical Science & Natural resources beijing 100101 （china）

Climate change scenarios, predicted using the regional climate modeling system of PRECIS (providing regional cli-mates for impacts studies), were used to derive three-layer variable infiltration capacity (VIC-3L) land surface model forthe simulation of hydrologic processes at a spatial resolution of 0.25° × 0.25° in the Haihe River Basin. Three climatescenarios were considered in this study: recent climate (1961-1990), future climate A2 (1991-2100) and future climateB2 (1991-2100) with A2 and B2 being two storylines of future emissions developed with the Intergovernmental Panel onClimate Change (IPCC) special report on emissions scenarios. Overall, under future climate scenarios A2 and B2, theHaihe River Basin would experience warmer climate with increased precipitation, evaporation and runoff production ascompared with recent climate, but would be still likely prone to water shortages in the period of 2031-2070. In addition,under future climate A2 and B2, an increase in runoff during the wet season was noticed, indicating a future rise in theflood occurrence possibility in the Haihe River Basin.

关键词： climate change regional climate modeling system runoff VIC-3L model

Oxygen and hydrogen isotopic compositions of coexistent minerals of the Tasigake alkali granite pluton,northern Xinjiang:constraints upon the cause of ^(18)O-D depletion and the ^(18)O/^(16)O exchange kinetics

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12期44卷 1086-1093页

作者： LIU Wei, ZHAO Zhenhua ZHANG Fuqin Research Center of Mineral resources Exploration, institute of Geophysics , Chinese Academy of Sciences , beijing 100101, china Guangzhou institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, china Research Center of Mineral Resource Exploration Institute of Geophysics Chinese Academy of Science Beijing China Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou China

Oxygen and hydrogen isotopic compositions have been determined of three coexistent mineral triplets of alkali feldspar, quartz, arfvedsonite of 11 samples collected from the Tasigake alkali granite pluton, Ulungur River region, northern Xinjiang. isotopic exchange with meteoric water during subsolidus cooling caused strong 18O-D depletion and the remarkable nonequilibrium 18O/16O relation between coexistent minerals. 18O/16O exchange kinetic effects of the three minerals are simultaneously and consistently modelled. Exsolution and microtextural reorganization of alkali feldspar, and infiltration of water have been mutually facilitated by each other. Shallow intrusion, and circulation of meteoric water throughout the pluton cool it effectively. As a result, the "heat engine" is rapidly extinguished, and the nonequilibrium 18O/16O relation is frosen.

关键词： 18O-D depletion isotopic exchange kinetics alkali granite Ulungur.

The impact of vegetation restoration on erosion-induced sediment yield in the middle Yellow River and management prospect

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第6期48卷 724-741页

作者： CHEN Hao1, ZHOU Jinxing2, CAI Qiangguo1, YUE Zhongqi3, LU Zhongchen4, LIANG Guanglin1& HUANG Jianguo5 1. Key laboratory of Water Cycle and Related land Surface Processes, institute of Geographic Sciences and Natural resources Re-search, Chinese Academy of Sciences, beijing 100101, china 2. institute of Forestry, Chinese Academy of Forestry Sciences, beijing 100091, china 3. Department of Civil Engineering, University of Hong Kong, Hong Kong, china 4. Eco-environmental Research Center, Chinese Academy of Sciences, beijing 100085, china 5. College of resources and Environment, Southwest Agricultural University, Chongqing 400716, china Correspondence should be addressed to Chen Hao 1. Key laboratory of Water Cycle and Related land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. institute of Forestry Chinese Academy of Forestry Sciences 100091 Beijing China 3. Department of Civil Engineering University of Hong Kong Hong Kong China 4. Eco-environmental Research Center Chinese Academy of Sciences 100085 Beijing China 5. College of resources and Environment Southwest Agricultural University 400716 Chongqing China

According to the characteristics of water and erosion environments of different natural zones on the Loess Plateau, this paper studies changes of vegetation types, distribution boundaries of forest and grass as well as restoration capacity of vegetation in different natural zones in the middle Yellow River. The annual precipitation of 530 mm is the critical annual pre-cipitation for forest and grass distribution in the middle Yellow River. Among the zonal and azonal environmental factors affecting watershed sediment yield, the intermediate diameter D50 (mm) of suspended load and forest coverage (V, %) play the leading role. Of them the effect weight of forest coverage (V, %) on catchments sediment yield is only 3.4% less than the role of the intermediate diameter (D50, mm), they are almost the same. To effectively control soil erosion in semiarid, especially in hilly-gullied areas and make sediment transport modulus reduce to less than 6000 t/km2, it is rather difficult by merely relying on natural restoration of forest. In the process of cultivated land conversion into forest land and grassland, measures suiting local conditions should be adopted in tree species selection and artificial afforestation (grass planting) based on management with biological measures for slopeland and engineering measures for hilly-gullied areas, so that watershed forest coverage in key counties can reach at least over 30%.Compared with the standard period of precipitation prior to the 1960s, with the decrease of an-nual precipitation at various periods, plant productivities decline to different degrees under natural conditions. The main reason accountable for the low survival rate of new seedlings and grass over years is due to precipitation decrease. In light with regression models of annual pre-cipitation and natural vegetation productivities, it is possible to obtain estimated values of wa-tershed natural vegetation productivity and eco-water consumption needed for the restoration to

关键词： vegetation restoration, eco-water requirement, watershed sediment yield, the middle Yellow River.

Estimation of Sand Transportation Rate for Fixed and Semi-Fixed Dunes Using Meteorological Wind Data

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第1期19卷 129-136页

作者： HU Xia LIU Lian-You LI Shun-Jiang XIAO Bi-Lin LIU Mu-Xin Key Lab of Environment Change and Natural Disaster Ministry of Education Beijing Normal Univeristy Beijing 100875 （China） Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs/Ministry of Education Beijing Normal University Beijing 100875 （China） State Key laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 21008 （China） institute of Plant Nutrition and resources Beijing Academy of Agriculture and Forestry Sciences Beijing 100097 （China） institute of Agricultural resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 （China）

Taibus County, Inner Mongolia, china, lies in a farming-pastoral ecotone, where severe wind erosion and various aeolian sand hazards are prevalent and fixed and semi-fixed sand dunes occur frequently. This study was conducted to investigate the relationships between sand transportation rate and wind speed for the fixed and semi-fixed sand dunes based on field measurements. The annual quantity of soil erosion by wind was estimated using meteorological wind data. The results indicated that the sand transportation rate in Taibus County in 2000 was 57.38 kg cm-1 year-1 for the semi-fixed dunes and 4.56 kg cm-1 year-1 for the fixed dunes. The total duration of erosive winds covered 12.5% of the time of the year, and spring posed the highest potential of sand transportation. Wind with low speed (≤ 17 m s-1) and high frequency plays a dominant role in sand transportation, while strong wind (≥ 17 m s-1) with low frequency significantly enhanced the sand transportation. Erosive wind speed, directions, and frequency were three crucial dynamic factors influencing sand hazards in the farming-pastoral ecotone. The dominant factors intensifying sand and dust storms in Taibus County might be related to the favorable wind condition in combination with the durable drought, which led to land desertification and vegetation degradation.

关键词： fixed and semi-fixed dunes meteorological wind data sand transportation rate wind erosion

Simulating the impacts of climate variation and land-cover changes on basin hydrology: A case study of the Suomo basin

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第9期48卷 1501-1509页

作者： CHEN Junfeng1,2, LI Xiubin2 & ZHANG Ming2 1. institute of Remote Sensing & GIS, Peking University, beijing 100871, china 2. institute of Geographical Sciences and Natural resources Research, Chinese Academy of Sciences, beijing 100101, china 1. institute of Remote Sensing & GIS Peking University 100871 Beijing China 2. institute of Geographical Sciences and Natural resources Research Chinese Academy of Sciences 100101 Beijing Chin

Impacts of land cover changes on watershed hydrology have been a long-term academic concern with acute dispute. But little attention has been paid to such effects on mesoscale river basins, where the society has a closer link to river hydrology. The present study focuses on a mesoscale river basin, the Suomo Basin that is located on the upper reaches of the Yangtze River. land covers in the basin in the years 1970, 1986 and 1999 were mapped. A lumped hydrologic model, CHARM, and a distributed hydrologic model, SWAT, were used to model the impacts of both land-cover change and climate variation on river runoff during the past four decades. The results show that the contribution of climate variation to the change of runoff regime makes up 60%―80%, while that of land cover changes only 20%.

关键词： climate variation, land-cover changes, Suomo Basin, CHARM model, SWAT model.