当前中国是一个经济发展极其不平衡的国家,地域之间差异巨大,协调整体经济增长与区域平衡日益成为中国政府和中外学者密切关注的焦点问题。因此,探讨其分析框架、政策措施及其措施效果具有十分重要的现实意义。本文主要研究了公共投资...当前中国是一个经济发展极其不平衡的国家,地域之间差异巨大,协调整体经济增长与区域平衡日益成为中国政府和中外学者密切关注的焦点问题。因此,探讨其分析框架、政策措施及其措施效果具有十分重要的现实意义。本文主要研究了公共投资政策与整体经济增长和区域平衡的关系,通过构建一个三区域连接的中国递推动态可计算性一般均衡(Computable General Equilibrium,CGE)模型,定量分析公共投资的地域分配政策的不同选择对整体经济增长和地区差距产生的影响,并考察由此产生的产业间和地区间的相互传导效应。展开更多
Recent development in the use of the environmental radionuclide caesium-137 for documenting rates and soil redistribution on the cultivated or uncultivated land and estimating rates of sediment deposition on represent...Recent development in the use of the environmental radionuclide caesium-137 for documenting rates and soil redistribution on the cultivated or uncultivated land and estimating rates of sediment deposition on represents an important advance that overcomes many of the limitations of the conventional techniques commonly applied in such investigations. A study on soil redistribution （including soil erosion and deposition） was carried out in the Dian Lake catchment, Yunnan Province, using ^137Cs and selected chemical properties. The average soil erosion rate was 1,280.2 t km^2 yr^-1. Soil erosion rate occurring on different parts of the slope was significantly different on different parts of the slope, increasing.from the top. the bottom to the middle slope. The average soil erosion rate is also different with the land use type and that of the cultivated land （1, 672. 8 t km^-2 yr^-1） is higher than oJ the uncultivated land （1.161.2t km^-2 yr^-1 ）. The result shows that landform, slope gradient and land use type are key factors that influence the size of soil erosion. In addition, we also find the SOC and TN contents and amount of the soil erosion to be correlated in the soil. With the soil erosion occurring, there are land degradation and the local eco-environmental problems, such as water eutrophication in Dian Lake.展开更多
Age and nature of the Budate Group in the Hailar Basin are of great significance in studying the evolution of the Hailar Basin and the Xing'an-Mongolian Orogenic Belt(XMOB).Zircon U-Pb ages of eight volcanic rocks...Age and nature of the Budate Group in the Hailar Basin are of great significance in studying the evolution of the Hailar Basin and the Xing'an-Mongolian Orogenic Belt(XMOB).Zircon U-Pb ages of eight volcanic rocks from the Budate Group and two basement granites in the Hailar Basin were reported in this study.The dating results indicated that the formation of these volcanic rocks was consistent with the emplacement of Late Paleozoic basement granite in age(356-290 Ma),i.e.,Early Carboniferous to Early Permian rather than Early Mesozoic.Combined with regional geology,it was concluded that the Budate Group is the component of the basement of the Hailar Basin,and these volcanic rocks were formed at an active continental margin,which is related to the closure of the Hegen Mountains suture zone.The captured Neoproterozoic zircons(814-873 Ma) were probably derived from the Neoproterozoic basement materials in the Ergun Block,implying the close genetic relationships between the Ergun Block(including the Hailar Basin) and the Siberian Block.展开更多
文摘当前中国是一个经济发展极其不平衡的国家,地域之间差异巨大,协调整体经济增长与区域平衡日益成为中国政府和中外学者密切关注的焦点问题。因此,探讨其分析框架、政策措施及其措施效果具有十分重要的现实意义。本文主要研究了公共投资政策与整体经济增长和区域平衡的关系,通过构建一个三区域连接的中国递推动态可计算性一般均衡(Computable General Equilibrium,CGE)模型,定量分析公共投资的地域分配政策的不同选择对整体经济增长和地区差距产生的影响,并考察由此产生的产业间和地区间的相互传导效应。
基金sponsored by the fund on soil ero-sion and silt source of Dian Lake catchment (Grant No. 40473052).
文摘Recent development in the use of the environmental radionuclide caesium-137 for documenting rates and soil redistribution on the cultivated or uncultivated land and estimating rates of sediment deposition on represents an important advance that overcomes many of the limitations of the conventional techniques commonly applied in such investigations. A study on soil redistribution （including soil erosion and deposition） was carried out in the Dian Lake catchment, Yunnan Province, using ^137Cs and selected chemical properties. The average soil erosion rate was 1,280.2 t km^2 yr^-1. Soil erosion rate occurring on different parts of the slope was significantly different on different parts of the slope, increasing.from the top. the bottom to the middle slope. The average soil erosion rate is also different with the land use type and that of the cultivated land （1, 672. 8 t km^-2 yr^-1） is higher than oJ the uncultivated land （1.161.2t km^-2 yr^-1 ）. The result shows that landform, slope gradient and land use type are key factors that influence the size of soil erosion. In addition, we also find the SOC and TN contents and amount of the soil erosion to be correlated in the soil. With the soil erosion occurring, there are land degradation and the local eco-environmental problems, such as water eutrophication in Dian Lake.
基金supported by the National Natural Science Foundation of China (Grant No. 40972041)
文摘Age and nature of the Budate Group in the Hailar Basin are of great significance in studying the evolution of the Hailar Basin and the Xing'an-Mongolian Orogenic Belt(XMOB).Zircon U-Pb ages of eight volcanic rocks from the Budate Group and two basement granites in the Hailar Basin were reported in this study.The dating results indicated that the formation of these volcanic rocks was consistent with the emplacement of Late Paleozoic basement granite in age(356-290 Ma),i.e.,Early Carboniferous to Early Permian rather than Early Mesozoic.Combined with regional geology,it was concluded that the Budate Group is the component of the basement of the Hailar Basin,and these volcanic rocks were formed at an active continental margin,which is related to the closure of the Hegen Mountains suture zone.The captured Neoproterozoic zircons(814-873 Ma) were probably derived from the Neoproterozoic basement materials in the Ergun Block,implying the close genetic relationships between the Ergun Block(including the Hailar Basin) and the Siberian Block.
