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ANNUAL LAMINATIONS IN THE SEDIMENTS OF HONGFENG LAKE, CHINA

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Chinese Geographical Science 1996年第4期6卷 375-382页

作者： Wu Fengchang wan guojiang(State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, the Chinese Academy of Sciences, Guiyang 550002, PRC) State Key Laboratory of Environmental Geochemistry Institute of Geochemistry the Chinese Academy of Sciences Guiyang PRC

Hongfeng Lake is an eutrophic freshwater atificial *** began to restore water in 1960. Three sediment cores were taken from both about 25m of water in the center of Hongfeng bake in May 1991. The stratigraphy of the three cores was easily matched .by using prominent marking horizons and characteristic aqnences of laminations. In three layer Samples studied, diatom and other algae taxa appear in repeating apuences. The presence of laminations may reflect either the regular changes of physical-chemical conditions within the lake or the variation in the intensity of erosion and transport of material from the catchment, pat iculaly where instability in the lake-water system has occult as a result of human activities. The larninations were mainly cantal by seasonal variation of envionmental conditions,particularly *** t of the previous examples, they have ben fo￣ at most recent Sediments, in a small freshwater lake in the eastern slOPe of the QinghaiXiZang Plateau, China in a subtropical climate, which is adenly controlled by ￣theastern and southwestern mon￣n. It is believed that it's the first reported instanceOf laminated lake sediments from China.

关键词： annual laminations Hongfeng Lake carbonate geochemistry

7~Be: A Geochemical Tracer for Seasonal Erosion of Surface Soil in Watershed of Lake Hongfeng, Guizhou, China

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Pedosphere 1996年第1期6卷 23-28页

作者： BAI ZHANGUO wan guojiang wanG CHANGSHENG wan XI HUANGRONGGUI P.H. SANTSCHIZ and M. BASKARANZ(1￣State Key Lab. Of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences,Guiyang 550002 (China))(2￣Department Of Marine Scien State Key Lab. of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550005 China Department of Marine Sciences Texas a K M University Galveston TX 77551 United States

e penetrative depth in undisturbed surface soil is within 4 mm.7￣Be activity shows exponential decrease with soil depth, which is expressed as a diffusion process.7￣Be penetrative depth in undisturbed surface soil is apparently deeper in the fall (0.22-0.37 g cm￣(-2) than in the spring (0.11-0.28 g cm￣(-2) at the same site; Whereas, ￣7Be apparent activity at the top of surface soil is higher in the spring (0.3-2.2 Bq g￣(-1_) than in the fall (0.2-0.5 Bq g￣(-1) at the same site. The ￣7Be inventory (189-544 Bq m￣(-2) changes with both locations and seasons. Although the ￣7Be flux to the earth's surface increases with amount of precipitation, its maximum inventory in the soil profiles decreases to 30%-40% after the rainy period. Calculated by the diffusion equation, the erosion and accumulation rates of soil particles are agreeable with the observation in situ., which shows that the rates in fall are 1.5 times those in spring. The eroded soil particles almost all have been removed on the tablelands rather than transported into the drainage system. This indicstes that the soil erosion process in the karst region is only partial transportation within a short distance.

关键词： e erosion trace Lake Hongfeng watershed surface soil

Appropriately adapted properties of hot-extruded Zn-0.5Cu-xFe alloys aimed for biodegradable guided bone regeneration membrane application

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Bioactive Materials 2021年第4期6卷 975-989页

作者： Wentai Zhang Ping Li Gang Shen Xiaoshan Mo Chao Zhou Dorothea Alexander Frank Rupp Jürgen Geis-Gerstorfer Haijun Zhang guojiang wan Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu610031China Section Medical Materials Science and Technology University Hospital TübingenOsianderstrasse 2-8Tübingen72076Germany Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing100083China Department of Oral and Maxillofacial Surgery University Hospital TübingenOsianderstrasse 2-8Tübingen72076Germany Department of Interventional and Vascular Surgery The Tenth People’s Hospital of ShanghaiTongji UniversityShanghai200072China National United Engineering Laboratory for Biomedical Material Modification Branden Industrial ParkQihe Economic&Development ZoneDezhouShandong251100China

Appropriately adapted comprehensive mechanical properties,degradation behavior and biocompatibility are prerequisites for the application of Zn-based biodegradable *** this study,hot-extruded Zn-0.5Cu-xFe(x=0.1,0.2 and 0.4 wt%)alloys were fabricated as candidates for biodegradable materials for guided bone regeneration(GBR)*** hot-extrusion process and Cu alloying were expected mostly to enhance the mechanical properties,and the Fe alloying was added mainly for regulating the *** microstructure,mechanical properties and in vitro degradation behavior were systematically *** ZnCuFe alloys were composed of a Zn matrix and FeZn13 *** increasing Fe content,a higher FeZn13 phase precipitation with larger particles was *** elongation declined significantly until fracture with increasing Fe content up to 0.4 wt%,the ZnCuFe(0.2 wt%)alloy achieved a good balance between mechanical strength and ductility,with an ultimate tensile strength of 202.3 MPa and elongation at fracture of 41.2%.Moreover,the addition of Fe successfully accelerated the degradation of ZnCuFe *** ZnCuFe(0.2 wt%)alloy showed relatively uniform corrosion in the long-term degradation ***,extracts of the ZnCuFe(0.2 wt%)alloy showed no apparent cytotoxic effects against L929 fibroblasts,Saos-2 osteoblasts or TAg periosteal *** ZnCuFe(0.2 wt%)alloy exhibited the potential to inhibit bacterial adhesion of Streptococcus gordonii and mixed oral *** study provides evidence that the ZnCuFe(0.2 wt%)alloy can represent a promising material for the application as a suitable GBR membrane.

关键词： Zn-based biodegradable metal Mechanical properties Degradation behavior Biocompatibility Guided bone regeneration membrane

The implication of tree-rings δ^(13)C for interaction between the atmosphere and the biosphere

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Chinese Science Bulletin 1999年第S2期44卷 83-85页

作者： wanG Shilu, wan guojiang and AN Ning State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

1 Background THE Ci/Ca, the ratio of intercellular and ambient C02 partial pressure, is internally controlled by thestomatal conductance and assimilation rate, and is externally affected by the atmospheric CO2 concentration and climate changes. Ci/Ca can be only estimated by the isotopic fractionation equation of Farquchar. However, this method is limited by the very little observation of atmospheric δ13 C before1980. Leavitt had to interpolate the atmospheric δ13 C by means of the polynomial. A geochemicalmethod to model Ci/Ca by tree-ring δ13C has been developed to reduce the dependence. By the estimated tree-ring Ci/ Ca, the authors here discuss C02 and water exchanges between the atmosphere and biosphere that greatly influence the climate

关键词： tree-rings δ13C carbon cycle water-use efficiency.

Relationship between δ^(13)C and index of ring width

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Chinese Science Bulletin 1999年第S2期44卷 81-83页

1 Materials and methods THE tree-ring reported here is one of pine discs sampled at 3 200 m a.s.l. in Qongtelian Valley in the Tuomu’er Peak region in 1978. The local geographical and climate condition has been introduced in detail. An index series was obtained after the width of tree-rings on 5 different radii was measured andfitted by linear and negative exponential functional regression. Each annual ring has been separated on the whole to simultaneously measure △14 C and δ13 C of treerings. Cellulose was extracted by the standard chemical method, then oxidized by copper oxide to C02.Carbon isotopic analyses were performed with a Mat-252 mass spectrometer. Results are expressed in thestandard δ notation with respect to the PDB standard with a precision of 0.1‰. 2

关键词： tree rings δ13C index of ring width correlation climate changes.

Theoretical calculation and experimental study of influence of oxygen vacancy on the electronic structure and hemocompatibility of rutile TiO_2

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Science China(Technological Sciences) 2009年第9期52卷 2742-2748页

作者： LEI YiFeng,LENG YongXiang,YANG Ping,wan guojiang & HUANG Nan Key Laboratory of Advanced Materials Technology of Ministry of Education,Department of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China Key Laboratory of Advanced Materials Technology of Ministry of Education Department of Materials Science and Engineering Southwest Jiaotong University Chengdu China

In this work,the relationship between electronic structure and hemocompatibility of oxygen deficient rutile TiO2-x was studied by both theoretical calculation and experimental study. Based on the local density functional theory,first-principals method was performed to calculate the electronic structure of rutile TiO2 with different oxygen vacancy concentration. In the range of less than 10% of (or equal) physically realistic O vacancy concentration,the band gap of rutile TiO2 increases with increasing O vacancy concentration,leading the TiO2 changes from a p-type to an n-type semiconductor. The valance band of TiO2 is predominated by O 2p orbital,while the conduction band is occupied by Ti 3d orbital for different O vacancy concentration. The O vacancy results in the occupation of electrons at the bottom of conduction band of TiO2,and the donor density increases with increasing O vacancy concentration. When materials come in contact with blood,the n-type semiconductor feature of oxygen deficient TiO2-x with the bottom of conduction band occupied by electrons would prevent charge transfer from fibrinogen into the surface of materials,thus inhibiting the aggregation and activation of platelets,therefore improving the hemocompatibility of rutile TiO2-x.

关键词： rutile TiO2 oxygen vacancy electronic structure hemocompatibility

High resolution environmental records in recent sediments of Erhai Lake, Yunnan Province

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Chinese Science Bulletin 1999年第S2期44卷 88-90页

作者： CHEN Jingan, wan guojiang and TANG Degui State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic changes. Along with the appearance of modern environmental problems including globalwarming, people are increasingly concerned about short-term climatic variations (annual to century scale)within the historical period. Therefore, it is an urgent and significant task for scientists to obtain continuous and high resolution natural records so as to reconstruct recent climatic changes truly and predict theclimate in the near future. As a main lodging of surface substances, the plateau-lake sediment continuously records the information of regional climate and environment with annual to decade resolution. Undoubtedly it is one

关键词： lake sediments high resolution climatic changes Erhai Lake.

回眸环境质量地球化学前期研究——纪念涂光炽先生九十华诞

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地学前缘 2010年第2期17卷 404-416页

作者：万国江中国科学院地球化学研究所环境地球化学国家重点实验室贵州贵阳550002

1973年涂光炽先生预言:"七十年代环境科学和生命科学将异军突起"、"环境科学与地球化学的相互渗透,产生了新的边缘分支学科——环境地球化学"。近40年来,环境质量的地球化学研究经历了调查评价—区域综合—界面机理三个发展阶段,在典型... 详细信息

1973年涂光炽先生预言:"七十年代环境科学和生命科学将异军突起"、"环境科学与地球化学的相互渗透,产生了新的边缘分支学科——环境地球化学"。近40年来,环境质量的地球化学研究经历了调查评价—区域综合—界面机理三个发展阶段,在典型区域环境演化及环境—生态效应方面取得了重要进展,并将在21世纪为人类谋求更多的福利。

关键词：环境质量地球化学研究区域环境环境评价环境界面

学习刘东生先生环境地质观、深入环境演化与过程研究——贺东生院士九十华诞

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第四纪研究 2007年第6期27卷 915-918页

作者：万国江中国科学院地球化学研究所环境地球化学国家重点实验室贵阳550002

1972年刘东生先生发表了"环境地质学的出现"。刘东生院士的环境地质观聚焦于:环境地质学发展的动力源于社会需要、地球环境系统的整体性及其与人类关系的相互依存性。35年来,地质环境的地球化学研究以区域环境质量和全球环境变化两大科... 详细信息

1972年刘东生先生发表了"环境地质学的出现"。刘东生院士的环境地质观聚焦于:环境地质学发展的动力源于社会需要、地球环境系统的整体性及其与人类关系的相互依存性。35年来,地质环境的地球化学研究以区域环境质量和全球环境变化两大科学问题作为基本目标,经历了调查评价-区域综合-界面机理的3个发展阶段,在典型区域环境演化及环境-生态效应方面取得了重要进展。环境地质学以"地质学与人类"为宗旨,将在21世纪为人类谋求更多的福祉。

关键词：刘东生环境地质观环境演化与过程