Based on GIS and statistical methods, with the help of searching historical literatures and calculating the landscape indices, the land use changes of Qian'an County in both spatial and temporal aspects from 1945 ...Based on GIS and statistical methods, with the help of searching historical literatures and calculating the landscape indices, the land use changes of Qian'an County in both spatial and temporal aspects from 1945 to 1996 has been analyzed in this paper. And the driving forces of land use changes and their ecological effects are discussed too. The main findings of this study are as follows: (1) Land use changed greatly in Qian'an during 1945-1996, characterized by a decrease in grassland, wetland and water bodies, and an increase in cultivated land, saline-alkali land, and the land for housing and other construction purposes. Grassland decreased by 175,828.66 ha, and cultivated land increased by 102,137.23 ha over the half century. Accordingly, the main landscape type changed from a steppe landscape to a managed agricultural ecosystem. (2) Results of correlation analysis show that the land use change in the study area was mainly driven by the socioeconomic factors. (3) The ecological effects of land use change in the area are characterized by serious salinization, degression of soil fertility and the weakening of landscape suitability.展开更多
This research studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer.Laboratory tests have been performed to characterize the equilibrium and ...This research studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer.Laboratory tests have been performed to characterize the equilibrium and kinetic adsorption properties of the activated carbon in cadmium-containing aqueous solutions.A 2D numerical model has been used to describe pollutant transport within a groundwater and the pollutant adsorption on the permeable reactive barrier(PRB).In particular,it has been considered the case of a PAB used to protect a lake or downstream from Cd(II)contaminated groundwater.Numerical results show that the PAB can achieve a long-term efficiency by preventing lake or downstream pollution for several months.展开更多
基金National Key Project of Basic Research Development of China,No.G1999043406National Natural Science Foundation of China,No.30200040
文摘Based on GIS and statistical methods, with the help of searching historical literatures and calculating the landscape indices, the land use changes of Qian'an County in both spatial and temporal aspects from 1945 to 1996 has been analyzed in this paper. And the driving forces of land use changes and their ecological effects are discussed too. The main findings of this study are as follows: (1) Land use changed greatly in Qian'an during 1945-1996, characterized by a decrease in grassland, wetland and water bodies, and an increase in cultivated land, saline-alkali land, and the land for housing and other construction purposes. Grassland decreased by 175,828.66 ha, and cultivated land increased by 102,137.23 ha over the half century. Accordingly, the main landscape type changed from a steppe landscape to a managed agricultural ecosystem. (2) Results of correlation analysis show that the land use change in the study area was mainly driven by the socioeconomic factors. (3) The ecological effects of land use change in the area are characterized by serious salinization, degression of soil fertility and the weakening of landscape suitability.
基金Supported by Project of National Key Programof Technology R&D the11th Five-year Plan(Nos.2007BAB28B04-03,2006BAB04A09-02)China Geological Survey Program(No.2003104001)+2 种基金Jilin Province Key Project of Science and Technology(Nos.20020401,20080543)Jilin Province KeyProject of Water Resources(Nos.YN20060328,HDS20060629)NSFC Project(No.40672157)
文摘This research studies the reliability of an activated carbon permeable reactive barrier in removing cadmium from a contaminated shallow aquifer.Laboratory tests have been performed to characterize the equilibrium and kinetic adsorption properties of the activated carbon in cadmium-containing aqueous solutions.A 2D numerical model has been used to describe pollutant transport within a groundwater and the pollutant adsorption on the permeable reactive barrier(PRB).In particular,it has been considered the case of a PAB used to protect a lake or downstream from Cd(II)contaminated groundwater.Numerical results show that the PAB can achieve a long-term efficiency by preventing lake or downstream pollution for several months.
