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Impacts of permafrost changes on alpine ecosystem in Qinghai-Tibet Plateau

Science china Earth sciences 2006年第11期49卷 1156-1169页

作者： WANG Genxu1,3., LI Yuanshou2 , WU Qingbai2 & WANG Yibo3.1. institute of Mountain Hazards and Environment, chinese Academy of sciences, Chengdu 610041, {3. 2. Cold and Arid Regions Environmental and Engineering Research institute, chinese Academy of sciences, Lanzhou 73.000, {3. 3. Resource and Environment School, Lanzhou University, Lanzhou 73.000, {3. 1. institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China 3. Resource and Environment School Lanzhou University Lanzhou 730000 China 2. Cold and Arid Regions Environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou 730000 China

Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. The interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun Mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. The results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. The alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. Those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 28.11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively

关键词： permafrost environment, alpine cold ecosystem, statistics relationship, climate change, impacts, Qinghai-Tibet Plateau.

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

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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 Environmental and Engineering Research institute, chinese Academy of sciences, Lanzhou 73.000, {3. 3. Resource and Environment School, Lanzhou University, Lanzhou 73.000, {3. 1. institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China 3. Resource and Environment School Lanzhou University Lanzhou 730000 China 2. Cold and Arid Regions Environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou 730000 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 28.12%, a base flow decline of 3..3.%, a drop in the maximum peak discharge of 3..77%, and mean discharge decreases in spring and autumn of 3..05% and 24.87% 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 resources and the proper development of the entire catchment.

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

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FACTORS INFLUENCING SOLID SOLUBILITIES OFRARE-EARTHS IN Pd

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 318-322页

作者： YN Ning and YT. Ning(kunming institute of Precious Metals, kunming 650221, {3.) kunming Inst of Precious Metals Kunming China

A parameter describing the solid solubilities of mre-earths in Pd, Nf/aX(TR - rPd),was proposed, where N is the fshell filled electron nutnben △X the electronegativity dtherence between Palladium and rare-earths, rR the atotnic radii of rare-earth elementand rPd of Pd. The marimum solid solubilities are linear relation to this parnmeterexcept La, Nd and Ce.

关键词： solid solubility rare-earth palladiutn

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Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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Science china(Technological sciences) 2005年第z1期48卷 1-17页

作者： LI Shihai1, LIAN Zhenzhong1,2 & J. G. Wang3.1. institute of Mechanics, chinese Academy of sciences, Beijing 100080, {3. 2. Graduate School, chinese Academy of sciences, Beijing 100060, {3. 3. Tropical Marine Science institute, National University of Singapore, Singapore 119260 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Singapore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

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Crustal structure of Gondwana-and Yangtze-typed blocks:An example by wide-angle seismic profile from Menglian to Malong in western Yunnan

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Science china Earth sciences 2005年第11期48卷 1828-1836页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2, TENG Jiwen1, Lü Qingtian3. LI Jiliang1, SUN Shanxue1 & WANG Xinzheng1 1. institute of Geology and Geophysics, chinese Academy of sciences, Beijing 100029, {3. 2. institute of Geophysics, chinese Seismological Bureau, Beijing 100081, {3. 3. institute of Deposition Resource, chinese Academy of Geological sciences, Beijing 10003., {3. 1. institute of Geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 2. institute of Geophysics Chinese Seismological Bureau 100081 Beijing China 3. institute of Deposition Resource Chinese Academy of Geological Sciences 100037 Beijing China

The wide-angle seismic profile between Menglian and Malong crosses the Baoshan block (Gondwana-typed), and Simao and southwestern Yangtze blocks (Yangtze-typed). By in-terpreting the wide-angle seismic data, we obtained the seismic crust/upper mantle structure of P-wave velocities together with the seismic reflections of these three blocks, Changning- Menglian and Mojiang suture zones among the mentioned three blocks. Our interpreting results demonstrate that the P-wave crustal velocity of Simao block is slower than that of Baoshan and southwestern Yangtze block and the crustal thickness gradually thickens from the Baoshan block, Simao to southwestern Yangtze block. Crustal reflection patterns of these three blocks have dis-tinct differences too. For the Gondwana-typed blocks, seismic reflections in the upper crust are well developed while in middle-lower crust they are very weak. The crustal reflections in the Yangtze block are very well developed. The crustal reflection patterns in Simao and southwest-ern Yangtze blocks are distinguishable. The average thickness of the crust in the studied area is about 40 km. And we make some discussions on the crustal thickening model of the three blocks in western Yunnan and tectonic setting of seismic developing and interaction of Gondwana and Yangtze blocks.

关键词： Gondwana blocks,Yangtze blocks,wide-angle profile,crustal structure,tectonic setting

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Two New Oxindole Alkaloids from Ervatamia yunnanensis

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chinese Chemical Letters 1999年第7期10卷 575-578页

作者： Yang YU Jin Ming GAO Ji Kai LIU(Department of Phytochemistry,kunming institute of Botany. The chinese Academy of {3.. kunming 650204) chinese Acad Sci Inst Bot Dept Phytochem Kunming 650204 Peoples R China

Two new oxindole alkaloids. 17-demethoxy-hydroisorhynchophylline 1 and 17-demethoxy-hydroisorhynchophylline N-oxide 2, have been isolated from the aerial parts of Ervatamin yunnanensis, and their structures were eluci... 详细信息

关键词： Ervatamia yunnanensis Tsiang Apocynaceae oxindole alkaloids

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Digital image analysis of palaeoenvironmental records and applications

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chinese Science Bulletin 2002年第23期47卷 1957-1963,2025-2026页

作者： SUN Donghuai1,2, LIU Yu2 & TAN Ming3.. South china Sea institute of Oceanology, chinese Academy of {3.. Guangzhou 5103.1, china 2. State Key Laboratory of Loess and Quaternary Geology, Earth Environmental institute, chinese Academy of {3., Xi’an 710075, china 3. institute of Geology and Geophysics, chinese Academy of {3., Beijing 100029, china South china Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China State Key Laboratory of Loess and Quaternary Geology Earth Environmental Institute Chinese Academy of Sciences Xi’an China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

Environmental change signals in geological or biological records are commonly reflected on their reflecting or transmitting images. These environmental signals can be extracted through digital image analysis. The analysis principle involves section line selection, color value reading and calculating environmental proxy index along the section lines, layer identification, auto-chronology and investigation of structure evolution of growth bands. On detailed illustrations of the image technique, this note provides image analyzing procedures of coral, tree-ring and stalagmite records. The environmental implications of the proxy index from image analysis are accordingly given through application demonstration of the image technique.

关键词： digital image environmental records.

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Dynamics of morphological changes for mitochondrial fission and fusion

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 680-689页

作者： WANG ShiQi 1,2,4 , FU ChangLiang 1,2 , ZHANG Yan 1,2 , CHEN Quan 3.& LONG Mian 1,2 1 Key Laboratory of Microgravity (National Microgravity Laboratory), Beijing 100190, china 2 Center for Biomechanics and Bioengineering, institute of Mechanics, chinese Academy of {3., Beijing 100190, china 3.State Key Laboratory of Biomembrane and Membrane Biotechnology, institute of zoology, chinese Academy of {3., Beijing 100101, china 4 institute of Vertebrate Paleontology and Paleoanthropology, chinese Academy of {3., Beijing 100044, china 1. Key Laboratory of Microgravity (National Microgravity Laboratory) Beijing 100190 China2. Center for Biomechanics and Bioengineering Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China4. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China3. State Key Laboratory of Biomembrane and Membrane Biotechnology Institute of Zoology Chinese Academy of Sciences Beijing 100101 China

Mitochondria experience continuous fusion and fission in a living cell, but their dynamics remains poorly quantified. Here a theoretical model was developed, upon a simplified population balance equation (PBE), to predict the morphological changes induced by mitochondrial fission and fusion. Assuming that both fission and fusion events are statistically independent, the survival probability of mitochondria staying in the fission or fusion state was formulated as an exponentially-decayed function with time, which depended on the time-dependent distribution of the mitochondrial volume and the fission and fusion rates. Parametric analysis was done for two typical volume distributions. One was Gamma distribution and the other was Gaussian distribution, derived from the measurements of volume distribution for individual mitochondria in a living cell and purified mitochondria in vitro. The predictions indicated that the survival probability strongly depended on morphological changes of individual mitochondria and was inversely correlated to the fission and fusion rates. This work provided a new insight into quantifying the mitochondrial dynamics via monitoring the evolution of the mitochondrial volume.

关键词： mitochondria morphology fission fusion dynamics modeling

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Paeonivayin, A New Monoterpene Glycoside from Paeonia delavayi

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chinese Chemical Letters 1999年第9期10卷 771-774页

作者： Yun Bao MA Da Gang WU Ji Kai LIU (Department of Phytochemistry,kunming institute of Botany.The chinese Academy of {3..kunming 650204) chinese Acad Sci Kunming Inst Bot Dept Phytochem Kunming 650204 Peoples R China

A new monoterpene glycoside named paeonivayin with other seven known compounds were isolated from the roots of Paeonia delavayi Franch. and their structures were determined by means of spectroscopic studies.

关键词： Paeonia delavayi Franch paeoniaceae monoterpene glycoside paeonivayin

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Modeling of elastic wave propagation on a curved free surface using an improved finite-difference algorithm

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Science china(Physics,Mechanics & Astronomy) 2004年第5期47卷 633-648页

作者： WANG Xiuming1,3.& ZHANG Hailan2 1. CSIRO Petroleum, ARRC, PO BOX 113., Technology Park, Bentley, WA 6102, Australia 2. institute of Acoustics, chinese Academy of sciences, Beijing 100080, {3. 3. Present address: institute of Acoustics, chinese Academy of sciences, Beijing 100080, {3. 1. CSIRO Petroleum ARRC Technology Park PO BOX 1130 6102 Bentley WA Australia 2. institute of Acoustics Chinese Academy of Sciences 100080 Beijing China

Based on existing direct and imaging methods of a staggered finite-difference scheme, an improved algorithm for staggered finite-difference is proposed to implement rugged topographic free boundary conditions. This method assumes that the free surface can be implemented with horizontal and vertical free surface segments and their corners; the free surface passes through the grid points of shear stress components, instead of the normal stress components. Imaging is carried out for stress components in both horizontal and vertical directions, thus increasing the accuracy. To update particle- velocities, imaging and updating are first performed in the horizontal direction, and then in the vertical direction. The numerical results for elastic flat horizontal free surface with the imaging method and those for flat free surfaces of various slope angles with the proposed method are compared, and are shown to be in good agreement. The advantage of the proposed method is that only the stresses are dealt with in implementing the free surface into the staggered algorithm, which improves computation efficiency.

关键词： elastic wave simulation, curved free surface, staggered finite-difference, algorithm stability.

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