Two wetland maps for the entire China have been produced based on Landsat data acquired around 1990 and 2000. Wetlands in China have been divided into 3 broad categories with 15 sub-categories except rice fields. In 1...Two wetland maps for the entire China have been produced based on Landsat data acquired around 1990 and 2000. Wetlands in China have been divided into 3 broad categories with 15 sub-categories except rice fields. In 1990, the total wetland area in China was 355208 km2 whereas in 2000 it dropped to 304849 km2 with a net loss of 50360 km2. During an approximate 10-year period, inland wetland reduced from 318326 to 257922 km2, coastal wetland dropped from 14335 to 12015 km2, while artificial wetland increased from 22546 to 34911 km2. The greatest natural wetland loss occurred in Heilongjiang, Inner Mon- golia, and Jilin with a total loss of over 57000 km2 of wetland. In western China, over 13000 km2 of wetlands were newly formed in Xinjiang, Tibet, and Qinghai. About 12000 km2 of artificial wetlands were also added for fish farm and reservoir constructions. The newly formed wetlands in western China were caused primarily by climate warming over that region whereas the newly created artificial wetlands were caused by economic developments. China’s wetland loss is caused mainly by human activities.展开更多
The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subd...The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subduction. A similar feature of the deformation in the Dabieshan UHP metamorphic rocks implies that these different tectonic units share the same geodynamic background. The early stage of deformation can be preserved on account of their relatively shallower subduction than that for UHP rocks. On the basis of an analysis of the geo- logical structure and geochronological results, five deformational stages have been recognized: a D1-Early compressional deformation which represents the continental subduction; a D2-Early exhumation deformation producing a syn-convergence exhumation; a D3-Main deformation, represented by an exhumation deformation with Late Triassic age; a D4-Doming and its margin extensional gravity collapse deformation and finally a D5-regional extensional deformation of Cretaceous that was mostly introduced by the migmatization and plutonism.展开更多
The physical basis of meridians and acupoints (acupuncture points) is in a complex system mainly of connective tissue and interwoven with the blood capillaries, nerves, lymph vessels,etc. Elements of Ca, P, K, Fe, Zn,...The physical basis of meridians and acupoints (acupuncture points) is in a complex system mainly of connective tissue and interwoven with the blood capillaries, nerves, lymph vessels,etc. Elements of Ca, P, K, Fe, Zn, Mn, etc are found concentrated in the deep connective tissue structures in locations corresponding to acupoints. On this physical basis, the specific waveband of high efficiency for transmission of infrared rays exists in the collagenous fibre in a liquid crystal state. The development direction and new idea of researching on acupuncture and meridians are discussed.展开更多
To develop and perfect the theory of plate tectonics and regional metallogeny, metal-logenesis during collisional orogenesis should be thoroughly studied and will attract increasing at-tention of more and more scienti...To develop and perfect the theory of plate tectonics and regional metallogeny, metal-logenesis during collisional orogenesis should be thoroughly studied and will attract increasing at-tention of more and more scientists. This paper presents the main aspects of research and discus-sions on metallogenesis during collisional orogenesis after the development of plate tectonics, and accordingly divides the study history into two stages, i.e. the junior stage during 1971-1990 and the senior stage after 1990. Beginning with the negation of mineralization in the collision regime by Guild (1971), the focus of study was put on whether there occurred any mineralization during collisional orogenesis at the junior stage. At the senior stage, which is initiated by the advance of met-allogenic and petrogenic model for collisional orogenesis, scientists begin to pay their attention to the geodynamic mechanism of metallogenesis, spatial and temporal distribution of ore deposits, ore-forming fluidization, relationship展开更多
Let (P, Q) be a C1 vector field defined in an open subset U IR2. We call inverse integrating factor a C1 solution V(x, y) of the equation . In previous works it has been shown that this function plays an important ro...Let (P, Q) be a C1 vector field defined in an open subset U IR2. We call inverse integrating factor a C1 solution V(x, y) of the equation . In previous works it has been shown that this function plays an important role in the problem of the center and in the determination of limit cycles. In this paper we obtain necessary conditions for a polynomial vector field (P, Q) to have a polynomial inverse integrating factor.展开更多
基金supported by a major research grant from National Natural Science Foundation of China (Grant No. 30590370)National Science and Technology Support Program (Grant No. 2006BAJ10B02)
文摘Two wetland maps for the entire China have been produced based on Landsat data acquired around 1990 and 2000. Wetlands in China have been divided into 3 broad categories with 15 sub-categories except rice fields. In 1990, the total wetland area in China was 355208 km2 whereas in 2000 it dropped to 304849 km2 with a net loss of 50360 km2. During an approximate 10-year period, inland wetland reduced from 318326 to 257922 km2, coastal wetland dropped from 14335 to 12015 km2, while artificial wetland increased from 22546 to 34911 km2. The greatest natural wetland loss occurred in Heilongjiang, Inner Mon- golia, and Jilin with a total loss of over 57000 km2 of wetland. In western China, over 13000 km2 of wetlands were newly formed in Xinjiang, Tibet, and Qinghai. About 12000 km2 of artificial wetlands were also added for fish farm and reservoir constructions. The newly formed wetlands in western China were caused primarily by climate warming over that region whereas the newly created artificial wetlands were caused by economic developments. China’s wetland loss is caused mainly by human activities.
基金the Chinesc National"973"Project(Grant No.G1999075506)the National Natural Science Foundation of China(Grant No.40202021)A post-doctor grant for Lin W.from the JSPS(02060)is also acknowledged.
文摘The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subduction. A similar feature of the deformation in the Dabieshan UHP metamorphic rocks implies that these different tectonic units share the same geodynamic background. The early stage of deformation can be preserved on account of their relatively shallower subduction than that for UHP rocks. On the basis of an analysis of the geo- logical structure and geochronological results, five deformational stages have been recognized: a D1-Early compressional deformation which represents the continental subduction; a D2-Early exhumation deformation producing a syn-convergence exhumation; a D3-Main deformation, represented by an exhumation deformation with Late Triassic age; a D4-Doming and its margin extensional gravity collapse deformation and finally a D5-regional extensional deformation of Cretaceous that was mostly introduced by the migmatization and plutonism.
文摘The physical basis of meridians and acupoints (acupuncture points) is in a complex system mainly of connective tissue and interwoven with the blood capillaries, nerves, lymph vessels,etc. Elements of Ca, P, K, Fe, Zn, Mn, etc are found concentrated in the deep connective tissue structures in locations corresponding to acupoints. On this physical basis, the specific waveband of high efficiency for transmission of infrared rays exists in the collagenous fibre in a liquid crystal state. The development direction and new idea of researching on acupuncture and meridians are discussed.
文摘To develop and perfect the theory of plate tectonics and regional metallogeny, metal-logenesis during collisional orogenesis should be thoroughly studied and will attract increasing at-tention of more and more scientists. This paper presents the main aspects of research and discus-sions on metallogenesis during collisional orogenesis after the development of plate tectonics, and accordingly divides the study history into two stages, i.e. the junior stage during 1971-1990 and the senior stage after 1990. Beginning with the negation of mineralization in the collision regime by Guild (1971), the focus of study was put on whether there occurred any mineralization during collisional orogenesis at the junior stage. At the senior stage, which is initiated by the advance of met-allogenic and petrogenic model for collisional orogenesis, scientists begin to pay their attention to the geodynamic mechanism of metallogenesis, spatial and temporal distribution of ore deposits, ore-forming fluidization, relationship
基金the DGICYT grant, number PB96-1153 The third author is partially supported by the University of Lleida Project P98-207.
文摘Let (P, Q) be a C1 vector field defined in an open subset U IR2. We call inverse integrating factor a C1 solution V(x, y) of the equation . In previous works it has been shown that this function plays an important role in the problem of the center and in the determination of limit cycles. In this paper we obtain necessary conditions for a polynomial vector field (P, Q) to have a polynomial inverse integrating factor.
