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An unusual isotopic fractionation of boron in synthetic calcium carbonate precipitated from seawater and saline water

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Science china Chemistry 2006年第5期49卷 454-465页

作者： xiAO Yingkai1,2.LI Shizhen1,WEI Haizhen1,SUN Aide1,ZHOU Weijian2.& LIU Weiguo2.1. Qinghai Institute of Salt Lakes,chinese academy of {2.,xining 810008,china 2. State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,chinese academy of {2.,xi’an 710075,china Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China

Inorganic calcium carbonate precipitation from natural seawater and salinewater at various pH values was carried out experimentally. The results show the clear positiverelationships between boron concentration and δ^(11)B of inorganic calcium carbonate with the pH ofnatural seawater and saline water. However, the variations of boron isotopic fractionation betweeninorganic calcite and seawater/saline water with pH are inconsistent with the hypothesis thatB(OH)_4^- is the dominant species incorporated into the biogenic calcite structure. The isotopicfractionation factors a between synthetic calcium carbonate precipitate and parent solutionsincrease systematically as pH increases, from 0.9884 at pH 7.60 to 1.0072.at pH 8.60 for seawaterand from 0.982. at pH 7.60 to 1.0178 at pH 8.75 for saline water. An unusual boron isotopicfractionation factor of larger than 1 in synthetic calcium carbonate precipitated fromseawater/saline water at higher pH is observed, which implies that a substantial amount of theisotopically heavier B(OH)_3 species must be incorporated preferentially into synthetic inorganiccarbonate. The results propose that the incorporation of B(OH)_3 is attributed to the formation ofMg(OH)_2.at higher pH of calcifying microenvironment during the synthetic calcium carbonateprecipitation. The preliminary experiment of Mg(OH)_2.precipitated from artificial seawater showsthat heavier ^(11)B is enriched in Mg(OH)_2.precipitation, which suggests that isotopically heavierB(OH)_3 species incorporated preferentially into Mg(OH)_2.precipitation. This result cannot beapplied to explain the boron isotopic fractionation of marine bio-carbonate because of thepossibility that the unusual environment in this study appears in formation of marine bio-carbonateis infinitesimal. We, however, must pay more attention to this phenomenon observed in this study,which accidentally appears in especially natural environment.

关键词： boron, isotopic fractionation, calcium carbonate precipitate, seawater, saline water.

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A study on volunteer augmentation navigation technology

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Science china(Physics,Mechanics & Astronomy) 2011年第6期54卷 1029-1034页

作者： WU HaiTao 1,2.LU xiaoChun 1,2.ZOU DeCai 1,2.& HAN Tao 1,2.1 National Time Service Center,chinese academy of {2.,xi’an 710600,china 2.Key Laboratory of Precision Navigation and Timing Technology,chinese academy of {2.,xi’an 710600,china National Time Service Center Chinese Academy of Sciences Xi’an China Key Laboratory of Precision Navigation and Timing Technology Chinese Academy of Sciences Xi’an China

Navigation augmentation technology is one of the most common methods to increase the continuity,reliability and integrity of the global satellite navigation *** concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this *** study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing *** neural cell model of Volunteer Augmentation Navigation using shared information is *** interactive general relative positioning is *** basic theories and methods of volunteer augmentation navigation are formed on the basis of the above-mentioned *** study of realization mechanism of volunteer augmentation technology helps to form a relatively integral architecture of volunteer augmentation navigation.A user self-service satellite navigation augmentation which combines information exchange and navigation services may strengthen the continuity,reliability and integrity of the navigation *** volunteer augmentation navigation theory proposed in this paper improves the traditional satellite navigation application model and expands the connotation and denotation of satellite navigation augmentation methods.

关键词： volunteer augmentation navigation self-organizing information exchange interactive general relative positioning

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Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 14 million years ago

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Science china Earth sciences 2004年第9期47卷 822-833页

作者： 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{2. 2. Qinghai Institute of Salt Lakes, chinese academy of sciences. xining 810008,{2. 3. Institute of Geology and Geophysics, chinese academy of sciences, Beijing 10002.,{2. 4. Department of Geography, Qinghai Normal University, xining 810008,{2. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining China Department of Geography Qinghai Normal University Xining China

A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races 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 identi- fied. 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 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, 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, re- spectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace se- quence provides an ideal geological record, of the uplift process of the northeastern 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 mil- lion 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 Tll 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 north- eastern Qinghai-Tibet Plateau during the late Cenozoic, and provides new evidence of previous thoughts

关键词： river terrace, tectonic uplift, loess-Red Clay, the past 14 million years, northeastern Qinghai-Tibet Plateau.

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Energy Transfer among Chlorophylls in Trimeric Light-harvesting Complex Ⅱ of Bryopsis corticulans

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Acta Biochimica et Biophysica Sinica 2006年第5期38卷 310-317页

作者： Su-Juan ZHANG~(1,2.)Shui-Cai WANG~2.Jun-Fang HE~2.Hui CHEN~3 1 Institute of Photonics and Photo-Technology,Northwest University,xi'an 710069,china 2.State Key Laboratory of Transient Optics and Photonics,xi 'an Institute of Optics and Precision Mechanics,chinese {2. of sciences,xi'an 710068.china 3 Laboratoty of Photosynthesis Basic Research,Institute of Botany,chinese {2. of sciences,Beijing 100093,china Institute of Photonics and Photo-Technology Northwest UniversityXi'an 710069 China State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi'an 710068 China Laboratory of Photosynthesis Basic Research Institute of Botany Chinese Academy of SciencesBeijing 100093 China

A study on energy transfer among chlorophylls（Chls）in the trimeric unit of the major light-harvesting complex Ⅱ（LHC Ⅱ）from Bryopsis corriculan,was carried out using time-correlated singlephoton *** the chlorophyll Q region of LHC Ⅱ,six molecules characterized as Chlb62.,Chlb646,Chlb652.54,657,Chla664666,Chla674677.680and Chla682.83were discriminated according to their absorption spectrumand fluorescence emission ***,excited by pulsed light of 62. nm,fluorescence kinetics spectrain the chlorophyll Q region were *** accordance with the principles of fluorescence kinetics,thesekinetics data were analyzed with a multi-exponential *** constants on energy transfer were *** overwhelming percentage of energy transfer among chlorophylls undergoes a process longer than 97picoseconds（ps）,which shows that,before transferring energy to another Chl,the excited Chl might convertenergy to vibrations of a lower state with different multiplicity（intersystem crossing）.Energy transfer at thelevel of approximately 10 ps was also obtained,which was interpreted as the excited Chls may go throughinternal conversion before transferring energy to another *** with a higher standard deviation,timeconstants at the femtosecond level can not be entirely excluded,which can be attributed to the ultrafastprocess of direct energy *** to the arrangement and direction of the dipole moment of Chls inLHC Ⅱ,the probability of these processes is *** fluorescence lifetimes of Chlb652.54,657,Chla664666,Chla674677.680and Chla682.83were determined to be 1.44ns,1.43 ns,636 ps and 713 ps,*** of energy dissipation in the pathway of fluorescence emission were no more than 40% in thetrimeric unit of LHC Ⅱ.These results are important for a better understanding of the relationship between thestructure and function of LHC Ⅱ.

关键词： energy transfer LHC Ⅱ transient spectrum fluorescence kinetics

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Astronomical function and date of the Taosi observatory

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Science china(Physics,Mechanics & Astronomy) 2009年第1期52卷 151-158页

作者： WU JiaBi1, CHEN MeiDong2.& LIU CiYuan3 1 National Astronomical Observatories, chinese academy of sciences, Beijing 100012. china 2.Institute for the History of Natural Science, chinese academy of sciences, Beijing 100010, china 3 National Time Service Center, chinese academy of sciences, xi’an 710600, china National Astronomical Observatories Chinese Academy of Sciences Beijing China Institute for the History of Natural Science Chinese Academy of Sciences Beijing China National Time Service Center Chinese Academy of Sciences Xi’an China

The Taosi site in xiangfen County,Shanxi Province,may be the capital of the King Yao. Archeologists recently discovered a large semi-circular stamped-earth platform, II FJT1,which has a clear and definite pounded-earth central core together with a curved wall perforated by twelve gaps. The platform is said to be an ancient observatory used to determine the seasons by watching the sunrise. Each feature of II FJT1 was precisely measured and the data are reproduced in this paper. An astronomical analysis of slots E2.and E12.was carried out using the azimuths of the slots' centerlines and the vertical angle of the mountain ridge opposite, above which the sun rises. The results show that at present the sun is close to the two slots but does not exactly enter them at summer and winter solstice sunrise. Using 14C analysis archeologists dated the site to about 2.00 BC. Because of the secular change in the obliquity of the ecliptic,at that date on the summer solstice the half-risen sun would have appeared inside slot E12.just to the right of the centerline,and on the winter solstice the sun would have been exactly on the centerline of slot E2. This result provides compelling proof that II FJT1 is an ancient observatory.

关键词： astro-archeology astro-chronology Taosi culture ancient observatory time service

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Integrated precise orbit determination of Shenzhou IV unmanned spacecraft

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Science china(Technological sciences) 2004年第5期47卷 518-525页

作者： L Congmin1,2. GU Yidong3, LIN Baojun3 & GUO Jiong3 1. Center for Space Science and Applied Research, chinese academy of sciences, Beijing 100080, china 2. Graduate School of the chinese academy of sciences, Beijing 100039, china 3. General Establishment of Space Science and Application, chinese academy of sciences, Beijing 100080, china Correspondence should be addressed to L Congmin Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China General Establishment of Space Science and Application Chinese Academy of Sciences Beijing China

Considering the characteristic orbit of Shenzhou IV spacecraft and the advantages and disadvantages of several types of domestic orbit measurements, a scheme of IPOD is determined, which uses GPS, SLR and USB observation data jointly plus precise ionosphere corrections to GPS observation data. IPOD system and mathematic models of OD are introduced. The results of different joint OD are analyzed using true observation data, and show that radial accuracy is better than 2.m.

关键词： Shenzhou IV unmanned spacecraft integrated precise orbit determination GPS SLR USB.

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The characteristic spectral lines of target atoms in the impact of^(40)Ar^(q+)ions on metal surfaces

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Science china(Physics,Mechanics & Astronomy) 2004年第6期47卷 729-736页

作者： ZHANG xiao’an1,2.ZHAO Yongtao1,2.LI Fuli1,YANG Zhihu2.xiAO Guoqing2.& ZHAN Wenlong2.1.Department of Applied Physics,xi’an Jiaotong University,xi’an 710049,china 2.Institute of Modern Physics,chinese {2. of sciences,Lanzhou 730000,china Department of Applied Physics Xi'an Jiaotong University Xi'an 710049 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

We report the measured results of the 2.0 nm—1000 nm characteristic spectral lines of target atoms when highly charged ions40Ar q+(6≤q≤14) with the same kinetic energy and40Ar6+ with different kinetic energies are incident upon Al, Ti, Ni, Ta and Au surfaces, respectively. The results for12.Xe6+,12.Xe10+ and12.Xe15+ with the same kinetic energy (150 keV) incident upon a Ta surface are also reported. These results show that when the projectile and target are properly selected (40Ar12. impinges on Al,12.Xe6+ impinges on Ta), the spectral intensity of characteristic spectral lines of the target atom is effectively enhanced, and is not strongly dependent on the kinetic energy of the incident ions.

关键词： highly charged ion, hollow atom, characteristic spectrum, spectral intensity.

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Possible effect of solar activity on variation of the tree-rings of a 500 a platycladus orientalis at the Mausoleum of Emperor Huang

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Science china(Physics,Mechanics & Astronomy) 2009年第4期52卷 631-639页

作者： FENG Bo1,2.& HAN YanBen1 1 xi’an Institute of Posts & Telecommunications,xi’an 710061,china 2.National Astronomical Observatories,chinese {2. of sciences,Beijing 100012.china xi’an Institute of Posts & Telecommunications Xi’an China National Astronomical Observatories Chinese Academy of Sciences Beijing China

The variation of the tree-ring's index of a platycladus orientalis at the Mausoleum of Emperor Huang and of a long series of sunspots relative number during AD1470-1974 are analyzed by using the wavelet power spectrum method,and their variation characters are also discussed. It is determined that the tree-ring's variation has cycles of approximate 2.7,11,93 and 150 a. Two data series are used for analyzing sunspot relative number(SSN) variation. First,the analysis of the annual average SSN during AD1700-1974 proved that variation cycles are about 11,50,and 93 a; then,the data during AD1465-1975 obtained from the decadal average SSN train over 7000 a reconstructed on the geomagnetic data is analyzed and its variation cycles are about 50,90,and 160 a. Besides the tree-rings cycle of 2.7 a is commonly considered to be related to ENSO,while 11 a cycle is related to solar Schwabe cycle; in addition,it is possible that the cycles of 90 and150 a are likely to be related to solar Gleissberg cycle and Suess cycle. The correlations between them are possibly due to the effect of solar activity on the climate and additionally on the tree's growth.

关键词： tree-ring solar activity climate change wavelet spectrum

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Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

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chinese Science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2.& WANG Zheng1,3 1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, chinese academy of sciences, xi’an 710075,{2. 2.xi’an Jiaotong University, School of Human Settlement and Civil Engineering, xi’an 710049,{2. 3 Graduate University of chinese academy of sciences, Beijing 100049,{2. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China School of Human Settlement and Civil Engineering Xi’an Jiaotong University Xi’an China Graduate University of chinese academy of sciences Beijing China

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2. to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3‰ to 7.2. with average of 4.1‰; and (2. mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

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Synthesis,crystal structure and thermal behavior of Rb(NTO)·H_2.

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chinese Science Bulletin 2001年第1期46卷 45-49页

作者： HU Mancheng, GAO Shiyang, LIU Zhihong, SONG Jirong, xiA Shuping & YU Kaibei1. Institute of Applied Chemistry, Shaanxi Normal University, xi’an 710062. china 2. Department of Chemical Engineering, Northwest University, xi’an 710069, china 3. Chengdu Branch of{2., Chengdu 610041, china Institute of Applied Chemistry Shaanxi Normal University Xi’an China Department of Chemical Engineering Northwest University Xi’an China Chengdu Branch of chinese academy of sciences Chengdu China

The Rb(NTO) .H2. crystal has been synthesized by reaction of 3-nitro-l,2.4-triazole-5-one (NTO) with Rb2.O3 in aqueous solution. Its crystal structure has been determined. The crystal belongs to monoclinic system. Crystal structure data: space group P2./ n; a = 0.633 0(1), b = 0.82. 1(2., c =1.2.6 4(3) nm; β = 97.90(1)°; V = 0.669 9 (2. nm3, Z = 4, Dc= 2.306 g/cm3,μ = 7.365 nm-1, F(000) = 448. An eight coordinated compound is formed between Rb+ with oxygen atoms and nitrogen atoms. A layer structure is formed by coordination bonds and hydrogen bonds. The thermal decomposition mechanism of this coordination compound is discussed.

关键词： Rb-NTO coordination compound crystal structrue thermal decomposition.

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