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1Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 14 million years ago显示文摘A typical sequence of fluvial terraces and aeolian deposits overlying these terraces were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 14 million years were obtained. At least 11 river terraces along Huangshui, the first-class tributary of Yellow River, at the Xining-Huzhu region are identified. While the first one (T1) is classified as an accumulation terrace, the others are all basement river terraces, which consist of the Tertiary sandstone and siltstone bedrock, fluvial gravel and pebbles and the overlying aeolian loess-Red Clay deposit. Samples from the aeolian deposits were examined for paleomagnetic stratigraphic reconstruction (1030 samples), luminescence dating (16 samples), magnetic susceptibility and grain-size distribution (more than 4000 samples). The luminescence dating and stratigraphic correlation suggest that terraces of T11, T10,T8, T7, T3, T2, T1 were formed at 14, 11.3, 1.55, 1.2, 0.15, 0.07 and 0.01 million years ago, respectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace sequence provides an ideal geological record of the uplift process of the northeastern Qinghai-Tibet during the past 14 million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 14, 11.3, 1.2 and 0.15 million years ago, respectively. The fluvial incision at the Xining-Huzhu region is less than 100 m during a period of ~12 million years in the Miocene era (between the T11 and T9), while the Huangshui River had incised 432 m during the past 1.2 million years (from T7 to the present floodplain). The river incision process clearly demonstrates that accelerated rising of the northeastern Qinghai-Tibet Plateau during the late Cenozoic, and provides new evidence of previous thoughts. There was a significant readjustment of the fluvial catchment during 1.55-1.2 million years ago: before this time, the paleoriver flowed to southwest. After this time the Huangshui River flows to southeast. A tectonic movement dominates reorganization of this fluvial system.LU Huayu1, WANG Xiaoyong1, AN Zhisheng1, MIAO Xiaodong1, ZHU Rixiang3, MA Haizhou2, LI Zhen4, TAN Hongbing2 & WANG Xianyan1 1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075 China 2. Qinghai Institute of Salt Lakes, Chinese Academy of Sciences. Xining 810008, China 3. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 4. Department of Geography, Qinghai Normal University, Xining 810008, China 2004Science China Earth Sciences2004,47,9:51
2Seasonal variation of potential denitrification rates of surface sediment from Meiliang Bay, Taihu Lake, China显示文摘The regulatory effects of environmental factors on denitrification were studied in the sediments of Meiliang Bay, Taihu Lake, in a monthly sampling campaign over a one-year period. Denitrification rates were measured in slurries of field samples and enrichment experiments using the acetylene inhibition technique. Sediment denitrification rates in inner bay and outer bay ranged from 2.8 to 51.5 nmol N2/(g dw (dry weight)·hr) and from 1.5 to 81.1 nmol N2/(g dw·hr), respectively. Sediment denitrification rates were greatest in the spring and lowest in the summer and early autumn, due primarily to seasonal differences in nitrate concentration and water temperature. For each site, positive and linear relationships were regularly observed between denitrification rate and water columnn itrate concentration. Of various environmental factors on denitrification that we assessed, nitrate was determined to be the key factor limiting denitrification rates in the sediments of Meiliang Bay. In addition, at the two sites denitrification rates were also regulated by temperature. The addition of organic substrates had no significant effect on denitrification rate, indicating that sediment denitrification was not limited by organic carbon availability in the sediments. Nitrate in the water column was depleted during summer and early autumn, and this suppressed effective removal of nitrogen from Taihu Lake by denitrification.Jicheng Zhong, Chengxin Fan, Guofeng Liu, Lei Zhang, Jingge Shang, Xiaozhi GuState Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. 2010Journal of Environmental Sciences2010,22,7:29
3Estimation on dynamic release of phosphorus from wind-induced suspended particulate matter in Lake Taihu显示文摘Through man-made disturbance experiments, the corresponding relationships be-tween suspended particulate matter (SPM) and wind speed in different lake areas were simu-lated, the physicochemical formal transformation and biological mineralizing and decaying processes of phosphorus in SPM were studied, the contribution of phosphorus transformation to phosphorus loading of the water of Lake Taihu was quantitatively estimated. The results show that about 0.44 t·a-1 loading in Lake Taihu mainly comes from phosphorus-releasing action of SPM in physicochemical transformed to soluble reactive phosphorus (SRP), and the contribution mainly from biological mineralizing and decaying was about 425.8 t·a-1, which is equal to 15.0% of the total external loading of Lake Taihu, namely 4.7—7.5 times as much as SRP loading en-tering the lake by the rivers; thus it is the important source in dynamical internal loading of the lake. The determining factors for dynamical internal loading in lakes are organic phosphorus content in suspended solid and its biological transition availability.FAN Chengxin1, ZHANG Lu1,2, QIN Boqiang1, WANG Sumin1, HU Weiping1 & ZHANG Chen1 1. Taihu Lake Laboratory for Ecosystem Research, Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008, China 2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China 2004Science China Earth Sciences2004,47,8:24
4Evidence of the Pan-Lake Stage in the Period of 40-28 ka B.P. on the Qinghai-Tibet Plateau显示文摘The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake’s surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+-28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.ZHENG Mianping, MENG Yifeng and Wei LejunResearch & Development Center of Saline Lake and Epithermal Deposits,Chinese Academy of Geological Sciences, Beijing 100037 2000Acta Geologica Sinica(English Edition)2000,74,2:22
5New progress of lake sediments and environmental changes research in China显示文摘Environmental change recorded by lake sediments is one of the important branches of the past global changes study. The new progress of lake sediments and environmental changes in China since the late 1980s has been comprehensively discussed. The highlights emphasized are Asian paleomonsoon migration reflected by lake level fluctuation, uplift of the Qinghai-Xizang Plateau recorded by lacustrine sediments, saltlake sediments andWANG Sumin and ZHANG ZhenkeLaboratory of Lake Sediment and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences , Nanjing 210008, China Department of Geography and Oceanology, Nanjing University , Nanjing 210093 , China 1999Chinese Science Bulletin1999,44,19:22
6A statistical model for porous structure of rocks显示文摘The geometric features and the distribution properties of pores in rocks were in- vestigated by means of CT scanning tests of sandstones. The centroidal coordi- nates of pores, the statistic characterristics of pore distance, quantity, size and their probability density functions were formulated in this paper. The Monte Carlo method and the random number generating algorithm were employed to generate two series of random numbers with the desired statistic characteristics and prob- ability density functions upon which the random distribution of pore position, dis- tance and quantity were determined. A three-dimensional porous structural model of sandstone was constructed based on the FLAC3D program and the information of the pore position and distribution that the series of random numbers defined. On the basis of modelling, the Brazil split tests of rock discs were carried out to ex- amine the stress distribution, the pattern of element failure and the inosculation of failed elements. The simulation indicated that the proposed model was consistent with the realistic porous structure of rock in terms of their statistic properties of pores and geometric similarity. The built-up model disclosed the influence of pores on the stress distribution, failure mode of material elements and the inosculation of failed elements.JU Yang1,2, YANG YongMing1, SONG ZhenDuo3 & XU WenJing4 1 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Beijing 100083, China 2 Department of Mechanical and Manufacturing Engineering, The University of Calgary, 2500 University Drive NW Calgary, AB T2N 1N4, Canada 3 China National Coal Mining Equipment Co. Ltd, Beijing 100011, China 4 Department of Materials and Metallurgy, The University of Utah, Salt Lake City, Utah 84112, USA 2008Science China(Technological Sciences)2008,51,11:21
7Palaeoclihlatic Indicators of China's Quaternary Saline Lake Sediments and Hydrochemistry显示文摘In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and give climatic parameters under the conditions of typical cold phase (mirabilite and natron), warm phase (thenar-dite) and slightly warm phase (bloedite) saline lake deposition.ZHENG Mianping, ZHAO Yuanyi and LIU JunyingResearch & Development Center of Saline Lake and Epithermal Deposits,Chinese Academy of Geological Sciences, Beijing 100037 2000Acta Geologica Sinica(English Edition)2000,74,2:17
8Characteristics of chlorine isotope distribution and analysis on sylvinite deposit formation based on ancient salt rock in the western Tarim Basin显示文摘During formation of the Tarim Basin, there repetitively happened seawater invasion for it was ever connected with wide Paleo-mediterranean Sea. At the same time, for the applica-tion of tectonic and paleoenvironmental condition, the basin deposits many sequences of thick strata of evaporites, especially in its two largest subbasins of Kuqa in the north and Shaqa in the southwest. Therefore, the western Tarim Basin has been considered to be a favorable location to prospect ancient sylvinite deposit. But it is unfortunate that the Br×103/Cl ratio, as a common geochemical index to uncover clues of sylvinite deposit, is almost invalid to indicate the stage of ancient brine condensation for very low content of bromine in salt rock samples (less than 10?6 commonly) in the western Tarim Basin evaporites. Fortunately, we noticed recently that the val-ues of chlorine isotope (δ 37Cl value) for salt rock samples follow some clear laws from place to place, which in the Shaqa subbasin, all δ 37Cl values of salt rock samples behaved negatively and on the contrary, they all surprisingly showed positive values in the Kuqa subbasin. Based on conclusions of previous research and referring to the ratios of Br×103/Cl for salt rock or brine samples, we proved that the chlorine isotope (δ 37Cl) could be used as an effective index to find ancient sylvinite deposit in those evaporites rock basin with low content of Br element back-ground, such as the Tarim Basin. Thus according to the new index of chlorine isotope, we con-clude that the concentration of ancient brines formed ancient salt rocks is much more concen-trated in the Shaqa subbasin than that in the Kuqa subbasin. Particularly, the δ 37Cl value of salt rock in Kashi depression of the western Shaqa subbasin is greatly negative (TAN Hongbing1,2, MA Haizhou1, XIAO Yingkai1, WEI Haizhen1,2, ZHANG Xiying1 & MA Wandong1 1. Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 2005Science China Earth Sciences2005,48,11:15
9为了“一湖清水”——鄱阳湖水利枢纽工程介绍显示文摘近年来,受长江上游干支流水库群汛后蓄水及鄱阳湖上游来水减少等因素影响,鄱阳湖出现持续的秋季低枯水位情况,给湖区民生、生态、经济等方面带来严重影响.针对这种不断加剧的影响,为保持鄱阳湖'一湖清水',江西省提出兴建鄱阳湖水利枢纽工程.本文围绕枢纽建设的必要性、工程规划、作用与效益以及目前围绕工程建设开展的研究工作等方面对枢纽工程进行全面细致的阐述,旨在让大家对鄱阳湖水利枢纽工程有进一步的了解和认知.Construction Office of Poyang Lake Water Control Project of Jiangxi Province(Construction Office of Poyang Lake Water Control Project of Jiangxi Province,Nanchang 330046,China) 2013江西水利科技2013,39,2:15
10Quantitative reconstruction of the paleosalinity at Qinghai Lake in the past 900 years显示文摘Based on the function relationship between the shell length of Limnocythere inopinata and the salinity of its living water in Tibetan Plateau lakes, the paleosalinty of Qinghai Lake in the past 900 years was reconstructed through the measurement of the adult body length of Limno-cythere inopinata. Meanwhile, the paleosalinity sequence of Qinghai Lake during the same period was rebuilt by the Sr/Ca ratio of the shell of Eucypris inflata combined with the Sr/Ca ratio of living ostracod valves from the species of ge-nus Eucypris inflata and the host water. The paleosalinity results obtained by two different methods were compared and assessed in this paper. To check the result, it was also contrasted with other historical climatic sequences of this area including tree ring and ice core. It was shown that the paleosalinity sequence rebuilt by adult ostracod body length had high reliability, and the paleosalinity reconstruction method by trace elements of ostracod shells was not suitable for Qinghai Lake. From the reconstructed paleosalinty se-quence of Qinghai Lake, it can be found that low salinity during 1160—1290 AD showed the humid climate condition on the Mediaeval Warm Period in this area, while the high salinity during 1410—1540 AD, 1610—1670 AD and 1770—1850 AD which was corresponding to the three cold pulses of the Little Ice Age with a dry climate condition. And the high salinity in the latest several decades was consistent with re-cent warm and dry trends of the climate in this area. The good consistency of the reconstructed palaeosalinity sequence and the precipitation sequence in this area rebuilt by tree ring proves the reconstruction of past lake salinity is reliable.ZHANG Enlou1,2,SHEN Ji1,WANG Sumin1,YIN Yu1,ZHU Yuxin1 & XIA Weilan1 1.Key Laboratory of Lake Sediment and Environment,Nanjing institute of Geography and Limnology,Chinese Academy of Sciences,Nan-jing 210008,China 2.Graduate School of Chinese Academy of Sciences,Beijing 100039,China Correspondence should be addressed to Zhang Enlou(e-mail:elzhang@ niglas.ac.cn) 2004Chinese Science Bulletin2004,49,7:14
11Whole fossil plants of Ephedra and their implications on the morphology,ecology and evolution of Ephedraceae (Gnetales)显示文摘Although there are many reports of fossil Ephedraceae,whole plant fossil record remains rare.Due to a lack of trust on partially preserved fossil materials,scholars working on molecular clock proposed a recent origin of Ephedra and cast doubt on the earlier origin time of Ephedraceae.To better the understanding on this interesting group,here we report whole plants of Ephedra hongtaoi sp.nov.(Ephedraceae,Gnetales) from the Yixian Formation (Early Cretaceous) in western Liaoning,China.These whole plants of Ephedra demonstrate clearly the characters of Ephedra,including shrubby growth habit,decussate branching pattern,and terminal ovuliferous unit with micropylar tube.The whole-plant preservation of the fossils provides more convincing fossil evidence of Early Cretaceous Ephedra,helps to resolve the controversy over the origin time of Ephedra,and sheds light on the whole plant morphology,growth habit,ecology and evolution of Ephedraceae.WANG Xin 1,2 & ZHENG ShaoLin 3 1 Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China 2 Fairy Lake Botanical Garden,Shenzhen 518004,China 3 Shenyang Institute of Geology and Mineral Resources,Shenyang 110034,China 2010Chinese Science Bulletin2010,55,15:12
12Study on Control Countermeasures of Agricultural Non-point Source Pollution in Lakeside Belt of Poyang Lake——Taking Duchang Section in the Lower Reaches of Poyang Lake as Example显示文摘[Objective] The aim was to study the control countermeasures of agricultural non-point source pollution in lakeside belt of Poyang Lake.[Method] The current situation of water quality of Poyang Lake was analyzed firstly,then the causes of agricultural non-point source pollution in Duchang section of Poyang Lake were studied,finally corresponding control countermeasures were put forward.[Result] Agricultural non-point source pollution in Duchang section of Poyang Lake was mainly related to the rapid development of pearl industry and livestock industry,aggravated soil erosion and excessive utilization of fertilizer.Based on analysis of current environmental situation and bearing capability of resources in Poyang Lake basin,agricultural non-point source pollution would be controlled through the reduction of external source pollution load,restoration of river wetland and construction of aquatic ecosystem.After the primary implementation of agricultural non-point source pollution control project,the amount of agricultural non-point source pollution in demonstration plot was reduced,and the quality of effluent met the first Class (Class A) of state Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).Meanwhile,biodiversity index in river wetland increased by about 30%,so the pollution load entering Poyang Lake was decreased.[Conclusion] The study could provide technology integration and demonstration for the environmental remediation in lakeside belt of Poyang Lake.ZHANG Yang-fan1,TAO Chun-yuan1,HUANG Yi2 1.Research Center of Poyang Lake Eco-economy,Jiujiang University,Jiujiang 332005,China 2.Duchang Poyang Lake Eco-economic Zone Construction Office,Duchang 332600,China 2011Meteorological and Environmental Research2011,2,7:12
13Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau显示文摘Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. Radioactive-nuclides such as 14C, 210Pb and 137Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 14C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 210Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 14C dating is stronger. Based on the analysis on results of 14C, 210Pb and 137Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 14C calendar ages, and establish the time sequence for cores CE-1 and CE-2 with result of 210Pb CRS model for the upper 35 cm and re-calculated 14C calendar age for sediments bellow 35 cm. Since 1400 cal. a BP, sedimentation inter-rupted for more than 1000 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.WU Yanhong1, WANG Sumin1& HOU Xinhua1,3 1. Key Laboratory of Lake Sedimentation and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China 2. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 10085, China 3. Graduate University of Chinese Academy of Sciences, Beijing 100039, China 2006Science China Earth Sciences2006,49,9:11
14Preliminary study on assessment of nutrient transport in the Taihu Basin based on SWAT modeling显示文摘With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995~2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu,occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.LAI Geying, YU Ge & GUI Feng Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing 210008, China The Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Key Lab of Poyang Lake Ecological Environment and Resource Development, Jiangxi Normal University, Nanchang 330027, China 2006Science China Earth Sciences2006,49,z1:11
15踏跳瞬间足后部骨骼的三维有限元分析显示文摘目的建立足部三维有限元模型,对足后部骨骼在踏跳中的应力分布进行分析。方法应用CT扫描和CAD/CAM软件处理,建立足后部骨骼三维模型。通过对背跃式跳高踏跳的足底压力测量和逆向肌肉力量计算,确定载荷约束条件,并进行有限元计算。结果获得了踏跳瞬间,跟骨、距骨、舟骨等易损伤部位的生物力学响应和应力分布,发现跟骨后距关节,距骨背面均为应力集中处。结论本研究建立的模型可用于足后部骨骼生物力学研究,为踏跳中的运动损伤力学机理提供数据。李建设 顾耀东 Mark Lake James Ren 曾衍钧 2008医用生物力学2008,23,2:9
16Preliminary examination of electrochemical and spectroscopic features of trithiocarbonate collectors for sulfide mineral flotation显示文摘The redox potentials of xanthate/dixanthogen (dithiocarbonate/di dithiocarbonate, DTC/(DTC) 2) and trithiocarbonate/di trithiocarbonate (TTC/(TTC) 2) couples have been measured for the potassium salts. The spectroscopic characteristics of these sulfide mineral collectors were determined by FTIR and UV analysis. Electrochemically controlled contact angle measurements at a pyrite surface provided the basis to analyze the effect of the functional group ( O CS 2 versus S CS 2) on the hydrophobic surface state. Results from this preliminary examination are discussed with respect to the nature of collector adsorption and the pyrite flotation response.R. Du Plessis 1, J.D. Miller 1, J.C.Davidtz 2 1. Department of Metallurgical Engineering, University of Utah, Salt Lake City, Utah 84102, USA 2. Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria 0002 2000中国有色金属学会会刊:英文版2000,10,S1:9
17Variation Characteristics of Water Environmental Capacity in Poyang Lake under the Scheduling of Three Gorges Reservoir显示文摘[Objective] The aim was to study the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir.[Method] Choosing chemical oxygen demand (COD),total nitrogen (TN) and total phosphorus (TP) as the control indexes of pollutants in Poyang Lake,the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir were analyzed based on the water environment mathematical models of organic compounds and nutrients.[Result] After the operation of Three Gorges Project,high water level in Poyang Lake lasted for a long time in flood season when Three Gorges Reservoir increased discharge volume,while water level went down obviously with the accelerating of recession flow when reservoir decreased discharge volume to store water,so Three Gorges Project had obvious effects on the hydrological regime of Poyang Lake.In 2009,when Three Gorges Reservoir stored water,the water environmental capacity of COD,TN and TP in Poyang Lake in October decreased by 14.0%,15.4% and 15.4% compared with those before operation,while they increased by 3.64%,4.88% and 4.88% in August when reservoir discharged water to prevent flood.[Conclusion] The study could provide scientific foundation for the water pollution control and water environment management of lakes.OU Ming-liang1,2,ZHOU Wen-bin2,3,HU Chun-hua2,3 1.College of Civil and Environment Engineering,East China Institute of Technology,Fuzhou 344000,China 2.Key Laboratory of Environment and Resource Utilization in Poyang Lake,Ministry of Education,Nanchang 330031,China 3.Institute of Environmental and Chemical Engineering,Nanchang University,Nanchang 330031,China 2011Meteorological and Environmental Research2011,2,3:8
18Boron isotopic fractionation in laboratory inorganic carbonate precipitation:Evidence for the incorpora-tion of B(OH)_3 into carbonate显示文摘A laboratory inorganic carbonate precipitation experiment at high pH of 8.96 to 9.34 was conducted, and the boron isotopic fractionations of the precipitated carbonate were measured. The data show that boron isotopic fractionation factors (αcarb-3) between carbonate and B(OH)3 in seawater range 0.937 and 0.965, with an average value of 0.953. Our results together with those reported by Sanyal and collabo-rators show that the αcarb-3 values between carbonate and B(OH)3 in solution are not constant but are negatively correlated with the pH of seawater. The measured boron isotopic compositions of carbonate precipitation (δ11Bcarb) do not exactly lie on the best-fit theoretical δ 11B4-pH curves and neither do they exactly parallel any theoretical δ 11B4-pH curves. Therefore, it is reasonable to argue that a changeable proportion of B(OH)3 with pH of seawater should also be incorporated into carbonate except for the dominant incorporation of B(OH)4- in carbonate . Hence, in the reconstruction of the paleo-pH of sea-water from boron isotopes in marine biogenic carbonates, the use of theoretical boron isotopic frac-tionation factor (α4-3) between B(OH)4- and B(OH)3 is not suitable. Instead, an empirical equation should be established.XIAO YingKai1,2, LI HuaLing1,3, LIU WeiGuo4, WANG XiuFang1 & JIANG ShaoYong5 1 Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China 2 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 3 Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China 4 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China 5 State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China 2008Science China Earth Sciences2008,51,12:8
19中国太湖1950年以来主要环境的变化和迅速富营养化的开始显示文摘太湖是我国第三大淡水湖,面积2350km2,位于长江三角洲(面积35000km2)的中部,自6000年前太湖形成以来,湖泊经历了几个主要变化。1950年以前,太湖最明显的变化发生在海侵和湖盆大小。海侵是太湖形成的主要原因。太湖形成后,在不同的干燥和湿润时期,湖盆经历了由一系列的小湖或统一湖盆之间的波动。但一般来说,近2000年以来,湖盆的大小在增大。然而1950年以后,为适应人口的增长,许多浅水地带被改造成农田和鱼塘。50年代以来,对湖盆和流域的进一步利用导致湖泊发生了一些变化。在这个阶段太湖的主要变化是:1)对排水流域、湖泊生态和营养状况具有重大影响的堤坝的修筑和湖岸的改造;2)始于1983/1984年湖泊的迅速富营养化。湖泊迅速富营养化的主要原因是由于工业、农业和城市化的迅速增长,导致未经处理的废水排入湖盆。每年这些营养物大量排入,对湖泊的营养状况影响甚重,在低水位时尤其如此。William Y.B.Chang(Center for Great Lakes and Aquatic Sciences and School of Natural Resources and Environment,the University of Michigan,Ann Arbor,Michigan 48109,U.S.A.andDivision of International Programs National Science Foundation,Foundation,Arlington, 1996古生物学报1996,35,2:8
20Atmospheric correction of HJ-1A/B CCD images over Chinese coastal waters using MODIS-Terra aerosol data显示文摘This paper demonstrates an atmospheric correction method to process HJ-1A/B CCD images over Chinese coastal waters with the aid of MODIS-Terra aerosol information.Based on the assumption of zero water-leaving radiance at the two near-infrared (NIR)bands or the shortwave infrared(SWIR)bands,the atmospheric aerosol optical depth(AOD)is firstly retrieved from MODIS-Terra with a simple extension of the NIR-SWIR combined atmospheric correction approach embedded in SeaDAS (SeaWiFS data analysis system).Then the'turbid'and'non-turbid'waters are separated by the turbid water index.Maximum probability of AOD at 551 nm band is derived based on the NIR information over'non-turbid'waters and FLAASH model is selected to do the atmospheric correction of the HJ-1A/B CCD imagery using the AOD values of highest probabilities as input.Similarly,according to the histogram of the AOD distribution at 551 nm band,the studied turbid water area is divided into several blocks and HJ-1A/B CCD imagery is corrected with the corresponding AOD values displayed with the highest frequency in each block.This method has been applied to several HJ-1A/B images over Chinese coastal waters and validated by synchronous in-situ data.The results have shown that this method is effective in the atmospheric correction process of HJ-1A/B CCD images for ocean color remote sensing study and application in the coastal waters.TIAN LiQiao 1,LU JianZhong 1,CHEN XiaoLing 1,2,3,YU ZhiFeng 1,XIAO JingJing 1,QIU Feng 1 & ZHAO Xi 1 1 State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China 2Key Laboratory of Poyang Lake Wetland and Watershed Research,Ministry of Education,Jiangxi Normal University,Nanchang 330022,China 3 The Key Laboratory of Poyang Lake Environment and Resource Utilization,Ministry of Education,Nanchang University,Nanchang 330031,China 2010Science China(Technological Sciences)2010,53,S1:8
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