检索结果-南通市图书馆

Heavy Metal Runoff in Relation to Soil Characteristics

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2001年第2期11卷 137-142页

作者： ZHAO XIULAN, QING CHANGLE and WEI SHIQIANG College Of resources and environmental {2., Southwest Agricultural University, {3. 400716 (china) 西南农业大学重庆 400716

Cu, Zn, Pb and Hg runoff from yellow limestone soil and purple soils and the relationships between the mobility of the heavy metals and the soil characteristics were studied in laboratory using a rainfall simulator. The results showed that the concentrations of soluble Zn in surface runoff were significantly negatively correlated with the contents of 2.mm particles and CEC of the soils, indicating that Zn was mostly adsorbed by clays in the soils. The contents of Cu and Hg in surface runoff were positively related to their contents in the soils. The amounts of Cu, Zn, Pb and Hg removed by surface runoff were influenced by the amounts of soil and water losses and their contents in the soils, and were closely related to the contents of soil particles 1-0.02.mm in size.

关键词： heavy metal mobility soil characteristics surface runoff

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 resources {2. and Technology, Beijing Normal University, Beijing 100875, china 2. Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland {2., Northeast Normal University, Changchun 13.02., china) MOE Key Laboratory of environmental Change and Natural Disasters College of Resources Science and Technology Beijing Normal University Beijing 100875 China Key Laboratory of Vegetation Ecology Ministry of Education Institute of Grassland Science Northeast Normal University Changchun 130024 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.

Research of E-Commerce System Based on EJB for Manufacture Enterprise

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

厦门大学学报（自然科学版） 2002年第S1期41卷 286-287页

作者： WEI Zhao-wen 1, LI Yong 2. SU Yi-dan 1 (1. Computer & Information Engineering College, Guangxi University, N anning 53.004, china 2. Business Administration College, {3. University,{2., Chi na)

During the popular and development in Internet, mor e and more EC systems are running on Internet. Manufacture enterprise establishes EC system, integrates the systems between enterprises replace the traditional MI S system. The manufacture enterprise will face some difficulties when it begins to establish EC system. In order to solve the difficulties, the EC system not on ly includes the functions which in general EC system, but also integrates ERP sy stem, manages the enterprise from three aspects: relationship between manufactur er and customers, enterprise resources, and supplying chain, and gives the manuf acturer more intelligent information. As the departments of enterprise exchange data very frequently, connect the sellers and suppliers by using Internet, the t raditional C/S architecture isn’t satisfied by present needs. It is the only wa y that uses Multi-tier architecture. EJB (Enterprise Java Bean) is a Multi-tier distributed architecture designed by SUN company. The Enterprise JavaBeans architecture is a component architecture for the development and development of component-based distributed business app lications. Applications written using the Enterprise JavaBeans architecture are scalable, transactional, and multi-user secure. These applications may be writt en once, and then deployed on any server platform that supports the Enterprise J avaBeans specification. There are many superiorities using EJB when design compu ter system. The EC System for Manufacture Enterprise is based on EJB architecture. We define four EJB containers, namely, CRM component, POM component, Knowledge Management component and ERP component. CRM EJBs take the form of managing the customer- supplier relationship, reducing the number of contracts the manufacturer must ma ke with the end customers. POM EJBs take the form of order processing activities . These order taking, order fulfillment, and managing the logistics and transpor tation involved in the physical movement of the

关键词： E-Commerce EJB CRM ERP

Test of magnetic susceptibility and grain-size age models of loess

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第11期17卷 1312-1317页

作者： Chen Yimeng1,2.3. Feng Zhaodong4 and Gong Huili1,2.1. MOE and Key Laboratory of resources Environment and GIS of Beijing, Beijing 10003.,{3. 2. Key Laboratory of 3. information Acquisition and Application, The Capital Normal University, Beijing 10003.,{3. 3. Department of Economics & Management of Huizhou University, Huizhou 516007,{3. 4. Key Laboratory of Western{3.’s environmental Systems, Ministry of Education, Lanzhou University, Lanzhou 73.000,{3.) MOE and Key Laboratory of resources Environment and GIS of Beijing Beijing 100037 China

Ages of the stratigraphic boundary MIS1/2.and MIS3.4 of the Yuanbu loess section in Linxia are used as the basis of the nodal control age. The age of MIS1/2.and MIS3.4 are obtained from the latest international research result—the climatic events recorded in the stalagmite in the Hulu Cave in Nanjing, that MIS1/2.is 11.5 kaB.P. and MIS3.4 is 59.8 kaB.P.. The ages of the two climatic events contain three nodal age control models (Model 1: 0 kaB.P.—59.8 kaB.P.; Model 2. 0 kaB.P.—11.5 kaB.P. and 11.5 kaB.P.—59.8 kaB.P.; Model 3. 11.5 kaB.P.—59.8 kaB.P.), which are used as the nodal control age separately. The deposition times of various stratigraphic horizons are calculated by using the magnetic susceptibility age model and grain-size age model, and then compared with each other. In addition, the AMS14C age, OSL age and the ages of YD and H events are compared with the ages of the corresponding horizons calculated by the three models of nodal control ages. From the analyses of lithologic characters and climatic stages it has been found that both the magnetic susceptibility age model and the grain-size age model have some defects. Because the accurate control ages are selected as the nodal points of the glacial period or interglacial period, the stratigraphic deposition times determined by the high resolution of magnetic susceptibility age model and grain-size age model approximate to the actual ages. As for the relative accuracy of the two age models, the magnetic susceptibility age model is more accurate than the grain-size age model.

关键词： loess nodal control age magnetic susceptibility age model grain-size age model test

Impact of land-use change on hydrological processes in the Maying River basin, 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

science china Earth sciences 2006年第10期49卷 1098-1110页

作者： WANG Genxu1,3. ZHANG Yu2. LIU Guimin2.& CHEN Lin3.1. Institute of Mountain Hazards and Environment, Chinese Academy of sciences, Chengdu 610041,{3. 2. Cold and Arid Regions {2. and Engineering Research Institute, Chinese Academy of sciences, Lanzhou 73.000,{3. 3. Resource and Environment School, Lanzhou University, Lanzhou 73.000,{3. Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Resource and Environment School Lanzhou University Lanzhou China Cold and Arid Regions environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of china. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest china, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 2..12., a base flow decline of 3..3.2}, a drop in the maximum peak discharge of 3..77%, and mean discharge decreases in spring and autumn of 3..05% and 2..87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73.-81%, and that to the influence of base flow reaching 62.-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water {2. and the proper development of the entire catchment.

关键词： land-use change, arid inland river catchment, hydrological process, impact, Maying River.

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, {13. 400716, china Correspondence should be addressed to Chen Hao Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Institute of Forestry Chinese Academy of Forestry Sciences Beijing China Department of Civil Engineering University of Hong Kong Hong Kong China Eco-environmental Research Center Chinese Academy of Sciences Beijing China College of resources and Environment Southwest Agricultural University 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 53. 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 3.%.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.

Simulation of energy and water balance in Soil-Vegetation-Atmosphere Transfer system in the mountain area of Heihe River Basin at Hexi Corridor of northwest china

在线全文

学校读者我要写书评

暂无评论

science china Earth sciences 2005年第4期48卷 538-548页

作者： KANG Ersi1, CHENG Guodong1, , SONG Kechao1, JIN Bowen1, , LIU Xiande3.2.3.& WANG Jinye3.1. Cold and Arid Regions environmental and Engineering Research Institute, Chinese Academy of sciences, Lanzhou 73.000,{2. 2. State Key Laboratory of Frozen Soil Engineering, Chinese Academy of sciences, Lanzhou 73.000,{2. 3. Academy of Water resources Conservation Forest of Qilian Mountains, Gansu Province, Zhangye 73.000,{2. Cold and Arid Regions environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China State Key Laboratory of Frozen nSoil Engineering Chinese Academy of Sciences Lanzhou China Academy of Water resources Conservation Forest of Qilian Mountains Gansu Province Zhangye China

In the mountain area of inland Heihe River Basin at Hexi Corridor of northwest china during the vegetation growing season from May to September, the Simultaneous Heat and Water (SHAW) model of Soil-Vegetation-Atmosphere Transfer (SVAT) system is applied to simulating and studying energy and water balance of the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope and the grassland at the sun-facing slope. The simulation of energy balance indicates that net radiation of the grass- land at the sun-facing slope is more than that of the Picea crassifolia forest and the grassland by the forest at the shaded slope. The energy outgoing components are the first latent heat and next sensible heat from the grassland both at the shaded slope and the sun-facing slope, but those at the former are less. The energy outgoing components are the first sensible heat and next latent heat from the Picea crassifolia forest. The composition and distribution of energy in the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope make the soil layer receive less energy, which therefore, especially the forest possesses the energy conditions for soil water conservation. The simulation of water balance indicates that the water loss of the grassland at the sun-facing slope is mainly caused by soil evaporation, while evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is less than that of the grassland at the sun-facing slope. Half of the evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is consumed by transpiration. After precipitation, the soil water storage is increased much more for the Picea crassifolia forest and also more for the grassland by the forest at the shaded slope. Therefore the shaded slope vegetation, especially the forest is favorable for soil water s

关键词： inland rivers, mountain vegetation zone, Soil-Vegetation-Atmosphere Transfer (SVAT) system, energyand water balance, simulation.

Israeli Water Achievements Today and Enlightenment to china

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,resources and Environment 2008年第4期6卷 72-77页

作者： Sun Lei1,2. Xu Lanqing3.1. Institute of environmental science and Engineering, Ocean University of{2., Qingdao Shandong 2.6100,{2. 2. Department of Soil and Water sciences, Faculty of Agricultural, Food and environmental Quality sciences, the Hebrew University of Jerusalem, 76100, Israel 3. Logistics Group of Ocean University of{2., Qingdao Shandong 2.6100,{2. Institute of environmental science and Engineering Ocean University of China Department of Soil and Water sciences Faculty of Agricultural Food and Environmental Quality Sciences the Hebrew University of Jerusalem Logistics Group of Ocean University

Despite the endemic drought, arid climate and associated limited freshwater resources, as well as difficult geopolitical realities, Israel can provide a reliable supply of high quality water to a rapidly growing population. The achievements of water supply in Israel can be summarized as water technologies (like water transportation and purification, desalination, wastewater treatment, effluent reuse, storm water catchment, control systems, rain enhancement and drip irrigation, etc.), water management and legislation as well as water industry. In view of the national concern regarding the quality and quantity of the water, the skills, technologies and know-how that Israel has accumulated in water supply and irrigation can give us enlightenment that is also presented in this paper.

关键词： Israel china water technology water management water industry

Combining Ridge with No-Tillage in Lowland Rice-Based Cropping System: Long-Term Effect on Soil and Rice Yield

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第4期19卷 515-522页

作者： JIANG Xian-Jun2.and XIE De-Ti College of resources and Environment, Southwest University, 2.6 Tiansheng Road, Beibei, {3. 400716 ({2.) College of resources and Environment Southwest University 216 Tiansheng Road Beibei Chongqing 400716 (China)

A tillage method of combining ridge with no-tillage (RNT) was employed in lowland rice-based cropping system to study the long-term effects of RNT on soil profile pattern, soil water stable aggregate distribution, nutrients stratification and yields of rice and post-rice crops. After flooded paddy field (FPF) was practiced with RNT for a long time, soil profile changed from G to A-P-G, and horizon G was shifted to a deeper position in the profile. Also the proportion of macroaggregate (> 2.mm) increased, whereas the proportion of silt and clay (3.mm) decreased under RNT, indicating a better soil structure that will prevent erosion. RNT helped to control leaching and significantly improved total N, P, K and organic matter in soil. The highest crop yields were found under RNT system every year, and total crop yields were higher under conventional paddy-upland rotation tillage (CR) than under FPF, except in 2.03.and 2.06 when serious drought occurred. RNT was proven to be a better tillage method for lowland rice-based cropping system.

关键词： aggregate-size distribution conservative tillage flooded paddy field soil profile pattern