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Genesis of excess argon in phengite and significance of ^(40)Ar-^(39)Ar age spectra for omphacite:A case study on UHP eclogite of South Dabie Terrain,china

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chinese Science Bulletin 2000年第15期45卷 1345-1351页

作者： WANG Songshan, GE Ningjie, SANG Haiqing & QIU ji1. institute of Geology and Geophysics,{2., beijing 10002., china 2. Department of Earth and Space Science, University of Science and Technology of china, Hefei 2.002., china correspondence should be addressed to Wang Songshan institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Department of Earth and Space Science University of Science and Technology of China Hefei China

The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4-1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.

关键词： South Dabie Terrain ultrahigh-pressure metamorphics phengite omphacite excess argon.

Adsorption behavior of hexadecyltrimethylammonium bromide (CTAB) to mica substrates as observed by atomic force microscopy

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Science china Chemistry 2005年第2期48卷 101-106页

作者： ZHAO Feng1,2. DU Yukou1, YANG Ping1, LI Xingchang2.& TANG ji’an2.1. Chemistry and Chemical Engineering Department, Suzhou University, Suzhou 2.5006, china 2. Key Laboratory of Colloid and Interface Science, institute of Chemistry,{2., beijing 100080, china correspondence should be addressed to Tang ji’an (email: jatang@***) Chemistry and Chemical Engineering Department Suzhou University Suzhou China Key Laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences Beijing China

Atomic force microscopy is employed to study the adsorption behavior of CTAB to mica surfaces. Results show that conformational transitions from globular micelles→cylindrical micelles→flat films are observed in the process of the adsorption of CTAB to mica at twice the bulk critical concentration. However, in 0.5 cmc CTAB solution, the adsorbed CTAB molecules to mica form the layered film structures, and apparent conformational transitions do not appear. Meanwhile, the phenomena of the adsorption of CTAB to mica and the dissociation of mica sur- faces are periodically observed.

关键词： atomic force microscopy (AFM), micelle, behavior of adsorption, the dissociation of mica surfaces.

Properties and applications of embryonic stem cells

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chinese Science Bulletin 2000年第14期45卷 1258-1265页

作者： GUO Xiaoxia & HE Fuchu1. beijing institute of Radiation Medicine, beijing 100850, china 2. Department of Life Science, Shandong University, ji’nan 2.0100, china correspondence should he addressed to He Fuchu beijing institute of Radiation Medicine Beijing China Department of Life Science Shandong University Ji’nan China

Mouse embryonic stem (ES) cells are pluripotent cells derived from the early embryo and can be propagated stably in undifferentiated state in vitro. They retain the ability to differentiate into all cell types found in the embryonic and adult body in vivo, and can be induced to differentiate into many cell types under appropriate culture conditions in vitro. Using these properties, people have set up various differentiated systems of many cell types and tissues in vitro. Through analysis of these systems, one can identify novel bioactive factors and reveal mechanisms of cell differentiation and organogenesis. ES cell-derived differentiated cells can also be applied to cell transplantation therapy. In addition, we summarized the features and potential applications of human ES cells.

关键词： embryonic stem cell differentiation in vitro cell transplantation therapy gene targeting.

Quantitative reconstruction of the paleosalinity at Qinghai Lake in the past 900 years

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chinese Science Bulletin 2004年第7期49卷 730-734页

作者： 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 {2. of sciences,Nan-jing 2.0008,china 2.Graduate School of chinese academy of sciences,beijing 100039,china correspondence should be addressed to Zhang Enlou(e-mail:elzhang@ ***) Key Laboratory of Lake Sediment and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Graduate School of chinese academy of sciences Beijing 100039 China

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—12.0 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.

关键词：青海湖数量重建成体特异湖浪介古盐度树轮海底沉积物介形亚纲动物

A 2.8 Ma record of environmental evolution and tectoni events inferred from the Cuoe core in the middle of Tibetan Plateau

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Science china Earth sciences 2004年第11期47卷 1025-1034页

作者： SHEN ji1,Lü Houyuan2.WANG Sumin1,CHEN Shiyue1,YANG Xiangdong1,WU Yanhong1 & ZHU Zhaoyu3 1.Nanjing institute of Geography and Limnology,chinese {2. of sciences,Nanjing 2.0008,china 2.institute of Geology and Geophysics,chinese {2. of sciences,beijing 10002.,china 3.Guangzhou institute of Geochemistry,chinese {2. of sciences,Guangzhou 510640,china correspondence should be addressed to Shen ji(email: jishen@***)

Based on a multi-proxy investigation into the deep core of the Cuoe Lake in the middle of Tibetan Plateau, a 2.8 Ma paleoclimatic and paleoenvironmental evolution is recon- structed. The result of magnetic stratum indicates that the lake basin was formed at about 2.8 MaBP, while the multi-proxy analyses of lithology, grain size, magnetic susceptibility and geo- chemical elements reveal that there have been three major environmental evolution stages and at least two intensive uplifts of the Tibetan Plateau in the lake basin area, i.e. during 2.8—2.5 MaBP, the lake basin came into being as a result of the disaggregation of the planation surface and rapid rising of the Tibetan Plateau. During 2.5—0.8 MaBP, with gradual uplift of the Tibetan Plateau, the environment of this area was more effectively controlled by the climatic cycle of the alternative glacial-interglacial stages. After 0.8 MaBP, the middle part of the Plateau accelerated its uplift and entered cryoshere.

关键词： Tibetan Plateau, 2.8 MaBP, environmental evolution, tectonic events, Cuoe Lake.