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Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

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Science china Earth sciences 2005年第12期48卷 2214-2230页

作者： YAN Jianzhong1,2.3. ZHANG Yili1, BAI Wanqi1, LIU Yanhua4, BAO Weikai5, LIU Linshan1, 2.& ZHENG Du1 1. institute of Geographic {3. and Natural Resources Research,{2., Beijing 100101, china 2. Graduate School of the{2., Beijing 10003., china 3. College of Resources and Environment, Southwest Agricultural University, Chongqing 400716, china 4. The Ministry of Science and Technology, P. C. china, Beijing 100862. china 5. Chengdu institute of Biology,{2., Chengdu 610041, china institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China College of Resources and Environment Southwest Agricultural University Chongqing China The Ministry of Science and Technology P. C. China Beijing China Chengdu institute of Biology Chinese Academy of Sciences Chengdu China

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2.00 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2.00, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.43.. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2.00, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found

关键词： land use/cover classification, upper Dadu River watershed, vegetation successions, GIS, RS.

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Kinetics of early methane generation from Green River shale

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chinese Science Bulletin 1998年第22期43卷 1908-1912页

作者： LIU Jinzhong\+1 and TANG Yongchun 2.1. Laboratory of Organic geochemistry, Guangzhou institute of geochemistry, chinese academy of sciences, Guangzhou 510640, china 2. Chevron Petroleum Technology Company, CA 9063., USA Laborarory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Chevron Petroleum Technology Company USA

During oil/gas exploration in an area, there is a question as to whether methane in the strata was generated \%in situ\% mainly by thermal degradation of local organic matter. The key to the question is whether the kerogen could produce methane of more than 80 mL/g TOC, when its \%R\%\-o increased from initial (0.3.%) to current value of 0.70% during thermal evolution. The authors have made efforts to answer this question by the kinetics method. First, a series of pyrolysis experiments were carried out to obtain data of methane yield and \%R\%\-o evolution, from which kinetic parameters of methane and \%R\%\-o were derived; then these parameters were extrapolated to the geological condition and finally, a methane yield, 96 mL/g TOC, was predicted. The result suggests that from the view of hydrocarbon generation, methane in the seam should be from thermal degradation of local kerogen.

关键词： methane kinetics pyrolysis organic geochemistry.

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Geochemical behavior of elements at fossil sea floor water/sediment interface

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chinese Science Bulletin 1999年第S2期44卷 232-233页

作者： ZHANG Haihua~1, XIA Yu~1, WANG Zuwei~2.and ZHOU Yongzhang~3.1. Guangzhou institute of geochemistry, {2. academy of Science, Guangzhou 510640, china 2. Department of Geography, Tianjin Normal University, Tianjin 3.0071, china 3. Department of Earth sciences, Zhongshan University, Guangzhou 5102.5, china Guangzhou institute of geochemistry Chinese Academy of Science Guangzhou 510640 China Department of Geography Tianjin Normal University Tianjin 300071 China Department of Earth sciences Zhongshan University Guangzhou 510275 China

THIS note deals with the geochemical behavior of elements near the water/sediment interface of a fossil seafloor. The Nandan-Hechi basin, located in northwest Guangxi, Southern china, is selected for exemplified study. It is an elongated basin, and developed on a Caledonian basement. Its Devonian strata hosthydrtothermally sedimentary formations, and are typical of the intra-platformal basin facies sediments oversouthern china. A steady sedimentary sequence may be observed, commonly going from carboniferouspelite at bottom, upward through bedded chert, thickly banded argillaceous limestone, thinly bandedsiliceous limestone and small lensiod argillaceous limestone in the middle, to coarse lensoid siliceousand/or argillaceous limestone at the top. The chert and some argillaceous limestone are related to hydrothermally sedimentary origin. The present study focuses on the lensoid argillaceous limestone formation. This formation contains the following characteristic sedimentary structures: small lensoid structure,vermiform structure, wave-shaped banded structure, massive structure, white framboid structure, andcage netting structure.

关键词： water/sediment interface sedimentation periodicity sedimentary geochemistry basin.

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Discovery of a pterodactylid pterosaur from the Yixian Formation of western Liaoning,china

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chinese Science Bulletin 2001年第13期46卷 1112-1117页

作者： WANG Xiaolin & LU Junchang1. institute of Vertebrate Paleontology and Paleoanthropology, chinese academy of sciences, Beijing 100044,{2. 2. College of Earth sciences and Resources,{2. University of Geo-sciences, Beijing 100083.{2. 3. Department of Geological sciences, Southern Methodist University, Dallas, TX 752.5, USA institute of Vertebrate Paleontology Chinese Academy of Sciences Beijing 100044 China

A well-preserved pterosaur with nearly complete skull is described from the Lower Cretaceous Yixian Formation at Sihetun in western Liaoning. It is characterized by a low and long crestless skull, slender and pointed teeth, long metacarpal, nearly equal length of metatarsals I -III and short pedal digit V. It is referred to a new genus and species of the family Pterodactylidae: Haopterus gracilis gen. et sp. nov. This is the first pterosaur with a nearly complete skull from the Jehol Biota; it also represents the first non-controversial fossil record of Pterodactylidae in Asia. Haopterus is more derived than Pterodactylus from the Late Jurassic Solnhofen in Germany. This discovery extends the distribution of the family Pterodactylidae from Europe and Africa to Asia and its latest occurrence from the Late Jurassic to the Early Cretaceous. The discovery of Haopterus gracilis provides further evidence for the study of the originand radiation of the Jehol Biota; it also sheds new light on the evolution and

关键词： western Liaoning Early Cretaceous Yixian Formation Pterodactylidae.

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Advances in the study of current-use non-PBDE brominated flame retardants and dechlorane plus in the environment and humans

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Science china Chemistry 2010年第5期53卷 961-973页

作者： LUO XiaoJun,CHEN SheJun,MAI BiXian & FU JiaMo State Key Laboratory of Organic geochemistry Guangzhou institute of geochemistry,{3. academy of sciences,Guangzhou 510640,china State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China

The fate of the high production volume,currently in use,and not regulated non-polybrominated diphenyl ether(PBDE) flame retardants,such as tetrabromobisphenol A(TBBPA) ,hexabromocyclododecane(HBCD) and dechlorane plus(DP),and the alternative flame retardants of PBDE,such as BTBPE and DBDPE,in the environment has attracted increasing attention and aroused concern due to the increasing regulation and phasing-out of *** paper reviews the distribution,bioaccumulation,human exposure and environmental behavior of those non-PBDE flame retardants in various environmental *** data gaps and needs for future research are discussed.

关键词： TBBPA HBCD BTBPE DBDPE DP

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Enzymatic cyclization of linear peptide to plant cyclopeptide heterophyllin B

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Science china Chemistry 2006年第1期49卷 63-66页

作者： JIA Aiqun1, LI Xiang2. TAN Ninghua1, LIU Xiaozhu3. SHEN Yuemao1 & ZHOU Jun1 1. State Key Laboratory of Phytochemistry and Plant Resources in West china, Kunming institute of Botany, Graduate Univer-sity of{2.,{2., Kunming 6502.4, china 2. chinese Peptide Co., Ltd, Hangzhou 3.0018, china 3. Southwest Forestry College, Kunming 6502.4, china State Key Laboratory of Phytochemistry and Plant Resources in West china Kunming Institute of Botany Graduate University of Chinese Academy of Sciences Chinese Academy of Sciences Kunming China chinese Peptide Co. Ltd Hangzhou China Southwest Forestry College Kunming China

The crude enzyme (PH-1) isolated from Pseudostellaria heterophylla by our group has catalyzed enzymatic cyclization of linear peptide NH2.Gly1-Gly2.Leu-Pro-Pro-Pro-Ile-Phe-COOH (4) into cyclopeptide heterophyllin B (HB) from plant for the first time. To ensure this reaction, some ana-lytical methods including TLC, HPLC, MS, NMR, and 13. labeling were used to prove that the reaction of substrate 4 sharing residue of NH-Phe-Gly-CO was successful.

关键词： Pseudostellaria heterophylla, cyclopeptides, HB, enzymatic cyclization, isotope labeled.

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Indian monsoon influences altitude effect of δ^(18)O in precipitation/river water on the Tibetan Plateau

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chinese Science Bulletin 2009年第15期54卷 2724-2731页

作者： YAO TanDong1,2. ZHOU Hang1,3.& YANG XiaoXin1,3.1 Key Laboratory of Tibetan Environment Changes and Land Surface Processes, institute of Tibetan Plateau Research, chinese academy of sciences, Beijing 100085,{2. 2.State Key Laboratory of Cryosphere sciences, Cold and Arid Regions Environmental and Engineering Research institute, chinese academy of sciences, Lanzhou 73.000,{2. 3.Graduate University of chinese academy of sciences, Beijing 100049,{2. Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China State Key Laboratory of Cryosphere sciences Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China Graduate University of chinese academy of sciences Beijing China

The δ 18O variation in precipitation acquired from 2. stations within the network of Tibetan Observation and Research Platform(TORP)is studied, with the focus on the altitude effect of δ 18O in river water during monsoon precipitation in an effort to understand the monsoon influence on isotopic composition in annual river water. It is found that δ 18O in precipitation on the Plateau is influenced by different moisture sources, with significant Indian monsoon influence on δ 18O composition in plateau precipitation and river water. The δ 18O of water bodies in the monsoon domain is generally more depleted than that in the westerly domain, suggesting gradual rainout of southwesterly borne marine moisture in the course of long-distance transportation and lifting over the Himalayas. The lapse rate of δ 18O in river water with altitude is the largest during monsoon precipitation, due to the increased temperature vertical gradient over the southern Plateau region controlled by monsoon circulation. The combination of δ 18O in river water in monsoon (wet) and non-monsoon (dry) seasons shows a larger lapse rate than that in non-monsoon (dry) season alone. As the altitude effect of δ 18O in precipitation and river water on the Tibetan Plateau results from the combined effect of monsoon moisture supply and westerly moisture supply, the δ 18O composition and its altitude effect on the Plateau during monsoon seasons should be considered in the reconstruction of paleoelevation of the Tibetan Plateau.

关键词：印度季风青藏高原降水

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Climate instability in the Yili region, Xinjiang during the last glaciation

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chinese Science Bulletin 2000年第17期45卷 1604-1609页

作者： YE Wei, DONG Guangrong, YUAN Yujiang & MA Yingjie1. Xinjiang institute of Ecology and Geography, chinese academy of sciences, Urumqi 83.011,{2. 2. Department of Geography, Zhejiang Normal University, Jinhua 3.2}004,{2. 3. institute of Desert Research, chinese academy of sciences, Lanzhou 73.000,{2. 4. Xinjiang institute of Meteorological Research, Urumqi 83.002.{2. Xinjiang institute of Ecology and Geography Chinese Academy of Sciences Urumqi China Department of Geography Zhejiang Normal University Jinhua China institute of Desert Research Chinese Academy of Sciences Lanzhou China Xinjiang institute of Meteorological Research Urumqi China

The climate is influenced by westerlies year in year out and the aeolian loess is widespread in the Yili region, the Xinjiang Uygur Autonomous Region. Through the study of the loess section with a thickness of 2..5 m, much useful information about climatic change in this region during the last glaciation was gotten. Grain size analysis of loess samples in the section showed that the climatic change in the Yili region was of instability during the last glaciation and similar to those of the North Atlantic Ocean and Greenland. In correspondence with the Heinrich events, the percentage of the size fraction of loess with grain size less than 10 μm decreased in cold stadials in the Yili region. This result suggests that the westerly wind be strengthened during the cold periods. Compared with the stadials, the content of the loess with grain size less than 10 μm was increased in interstadials, which indicated that the strength of the westerly wind was weakened. It is obvious that the climate was instable

关键词： Yili region last glaciation climate instability.

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Quaternary marine transgressions in eastern china

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Journal of Palaeogeography 2012年第2期1卷 105-125页

作者： Lin Jingxing1, 3. Dai Luping2. 3.1. institute of Geology, chinese {2. of Geological sciences, Beijing 10003., china 2. Key Laboratory of Marine Ecology and Environmental sciences, institute of Oceanology, chinese academy of sciences, Qingdao 2.6071, china 3. College of Earth Science, Graduate University of chinese academy of sciences, Beijing 100049, china institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China College of Earth Science Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Marine Ecology and Environmental sciences Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Based on the data from 117 holes (9151 samples) and the research on ecology and palaeoecology of Foraminifera combined with that on Ostracoda, diatoms, pollen and spores, eight marine transgressions have been recognized in the great plain regions through the Quaternary sequences and two marine transgressions have been found since the Late Pleistocene in the coastal plain (bedrock coast) areas. In the North china Plain, these are in ascending order:the Bohai transgression in the Early Pleistocene, the Haixing and Huanghua transgressions in the Middle Pleistocene, the Baiyangdian and Cangzhou transgressions in the Late Pleistocene, and the Tianjin transgression in the Holocene. In the Yangtze River Delta region the Rugao and Zhoupu transgressions occurred in the Early Pleistocene, the Shanghai, Jiading, and Wangdian transgressions in the Middle Pleistocene, the Jiangyin and Ge Hu transgressions in the Late Pleistocene, and the Zhenjiang transgression in the Holocene. In the coastal plain (bedrock coast) areas of North china, the Cangzhou transgression was recorded in the Late Pleistocene and the Tianjin transgression in the Holocene, whereas in South china the Fuzhou transgression took place in the Late Pleistocene and the Changle transgression in the Holocene. The transgressions correspond to warm periods and regressions to cold periods. The younger transgressions were not only of shorter duration, but also of larger magnitude. These findings point to the existence of four flood event strata since the Middle Pleistocene: two in the late Middle Pleistocene and another two in the Late Pleistocene.

关键词： Quaternary marine transgressions palaeoclimate eastern china

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A 12.bit multichannel ADC for pixel detectors in particle physics and nuclear imaging

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Science china(Technological sciences) 2010年第5期53卷 1208-1214页

作者： WEI Wei1,2.3.WANG Zheng1,3.& ZHAO JingWei1,3.1 institute of High Energy Physics,chinese {2. of sciences,Beijing 100049,china 2.Graduate University of chinese academy of sciences,Beijing 100049,china 3.Key Lab of Nuclear Detection Technology and Nuclear Electronics of chinese academy of sciences,Beijing 100049,china institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Key Lab of Nuclear Detection Technology and Nuclear Electronics of chinese academy of sciences Beijing China

Modern pixel detectors in nuclear and particle physics experiments and also in nuclear imaging,starve for highly integrated application specified integrated circuit(ASIC),whereas in china the study of ASIC still stays far away from practical *** lack of ASIC strictly limits the research and development of domestic high energy physics field.A 12.bit multichannel ADC designed for high density readout is introduced as a major candidate for solution.A precise model is discussed and the simulation fully agrees with the model,which indicates a key principle of *** is performed according to the given rule,and novel layout techniques are carried *** results in all aspects are also obtained,showing an excellent real performance,which satisfies the practical requirement.

关键词： application specified integrated circuit high density readout Wilkinson ADC multi-channel ADC

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