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Numerical study of the auroral particle transport in the polar upper atmosphere

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Science china(Technological sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3.1 School of Electronic Information, wuhan university, wuhan 43.079,{3. 2 Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, wuhan 43.079,{3. 3.School of earth and Space sciences, Peking university, Beijing 100871,{3. 1. School of Electronic Information Wuhan University Wuhan 430079 China 2. Key Laboratory of Geospace Environment and Geodesy Ministry of Education of PRC Wuhan 430079 China 3. School of earth and Space sciences Peking University Beijing 100871 China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

Ultra-microbes are the minerogenetic constructors of oceanic polymetallic nodules

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Chinese Science Bulletin 1997年第8期42卷 617-624页

作者： CHEN Jianlin, ZHANG Fusheng and BIAN Lizeng1 Second Institute of Oceanography, State Oceanic Administration, Hangzhou 3.0012, china 2 Center for Materials Analysis, Nanjing university, Nanjing 210093. china 3. Department of {3. sciences, Nanjing university, Nanjing 210093. china Second Institute of Oceanography State Oceanic Administration Hangzhou China Centu for Materials Analysis Nanjing University Nanjing China Department of earth sciences Nanjing University Nanjing China

Polymetallic nodules (mangnese nodules) are a typical kind of manganese oncolites The distribution of smooth sur-face and knobbly manganese nodules is closely related to the geological background of the mine field. A systematic study on their inner laminae structure and features suggests that they are the products of millions of years reproduction and accumulation of the recently found Miniactinomyces chinensis and Spirisophaerospora pacijica .

关键词： oceanic manganese nodule stromatolite ultra-microbe biolite.

Behavioral Diversity and Complexity Indicated by Metazoan Traces at a Topological Level since Proterozoic

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Journal of earth Science 2000年第3期19卷 118-124页

作者： Gong Yiming faculty of earth sciences,{3. university of Geosciences, wuhan 43.074,{3.

On the basis of topological criteria, metazoan traces can be classified as four ichnoorders (clusters) and twenty two ichnofamilies (kinds), which consist of nine basic and three combined topological configurations. At a topological level, the behavioral diversity and complexity indicated by metazoan traces have remained quite stable since the Early Cambrian. Dramatic changes of these traits took place in the Neoproterozoic, in which 75% (12/16) of the topoichnotaxa and all nine basic topological configurations of metazoan traces occurred, but the most complex and highest level topological configuration occurred in the Early Cambrian of the coelomate animal explosive evolution, showing that in the Neoproterozoic and Early Cambrian gestated not only the Ediacarian fauna and all the basic types of multi cellular animals known today, but also all the basic and the most complex metazoan traces through geological time.

关键词： metazoan trace topological configuration Proterozoic.

Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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Science china earth sciences 2006年第5期49卷 554-560页

作者： FAN Ke1,2,3.& WANG Huijun2 1. Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 100029, china 2. Department of Atmospheric Science, Yunnan university, Kunming 650091, china 3. Graduate university of the Chinese Academy of sciences, Beijing 100049, china 1. Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Department of Atmospheric Science Yunnan University Kunming 650091 China 3. Graduate university of the Chinese Academy of sciences Beijing 100049 China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

EPR studies of Mn^(2+) in the Loess Plateau of central china: Implication for variation of the East Asia summer monsoon

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Chinese Science Bulletin 1998年第1期43卷 72-75页

作者： CHEN Jun\+1, JI Junfeng\+1, SU Yuanxia\+2 and LU Huayu\+3.. Department of earth sciences, Nanjing university, Nanjing 210093.{3. 2. Center of Material Analysis, Nanjing university, Nanjing 210093.{3. 3. Xi’an Laboratory of Loess and Qu Department of earth sciences Nanjing University Nanjing China Center of Material Analysis Nanjing University Nanjing China Xi’an Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an China

Mn 2+ EPR intensity recorded in the Chinese loess_paleosol sequence shows close correlation with magnetic susceptibility and Sr content as well as the oscillation of paleoclimate. Thus Mn 2+ EPR signal can serve as an... 详细信息

关键词： paleomonsoon loess paleosol EPR signal of Mn 2+

Approximation of dense-n/2-subgraph and table compression problems

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Science china Mathematics 2005年第9期48卷 1223-1233页

作者： XU Dachuan~1 HAN Jiye~2 & DU Dongle~3.1. College of Applied sciences,Beijing university of Technology,Beijing 100022,china 2. Institute of Applied Mathematics,Academy of Mathematics and Systems Science,Chinese Academy of sciences,Beijing 100080,china 3. faculty of Administration,university of New Brunswick,P.O.Box 4400,Fredericton,NB E3. 5A3.Canada College of Applied sciences Beijing University of Technology Beijing 100022 China Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China faculty of Administration University of New Brunswick P.O. Box 4400 Fredericton NB E3B 5A3 Canada

We develop improved approximation algorithms for two NP-hard problems: the dense-n/2-subgraph and table *** on SDP relaxation and advanced rounding techniques,we first propose 0. 5982 and 0. 5970-approximation algorithms respec- tively for the dense-n/2-subgraph problem (DSP) and the table compression problem (TCP). Then we improve these bounds to 0. 6243.and 0. 6708 respectively for DSP and TCP by adding triangle inequalities to strengthen the SDP *** results for TCP beat the 0. 5 bound of a simple greedy algorithm on this problem,and hence answer an open question of Anderson in an affirmative way.

关键词： dense-n/2-subgraph problem(DSP) table compression problem(TCP) SDP approximation ratio

The microbial metallogeny of weathering crust REE deposits in South china

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Chinese Science Bulletin 1999年第S2期44卷 71-73页

作者： CHEN Binghui~(1,2), WANG Zhimei~3. HUANG Limei~3. WU Fuhai~3. CHEN Jingde~2 and XU Wenlie~2 1. Department of earth sciences, Nanjing university, Nanjing 210093.{3. 2. Department of earth sciences, Zhongshan university, Guangzhou 510275,{3. 3. Guangdong Pharmaceutical College, Guangzhou 510244,{3. Department of earth sciences Nanjing University Nanjing 210093 China Department of earth sciences Zhongshan University Guangzhou 510275 China Guangdong Pharmaceutical College Guangzhou 510244 China

VERY little is known about the roles of microorganisms in the metallogeny of weathering crust REE deposits, although there has been much literature on REE behavior in weathering conditions. The present note deals with the microorganisms in 4 weathering profiles of an REE deposit and their roles in migration and accumulation of REE in weathering conditions. 1 Cultivation and identification of microorganisms Under strict sterilization, samples were collected from various parts of 4 weathering profiles of granites in a weathering crust REE deposit in South china. The samples were then cultivated for microorganisms with ordinary agars as culture media and then the cultivated microorganisms were dyed and identifiedunder a microscope. The sampled positions and cultivated numbers of microbial colonies are shown

关键词： microbial metallogeny weathering crust REE deposit South china.

Sorption of Eu^(3.) onto nano-size silica-water interfaces

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Science china earth sciences 2005年第11期48卷 1942-1948页

作者： HU Ping1,2, YIN Xiulan3., ZHAO Linghu1 & LI Dien4 1. Department of earth sciences, china {3. of Geosciences, wuhan 43.074, china 2. Northeastern Illinois {3., Chicago, IL 60625, USA 3. china Institute of Geo-Environmental Monitoring, Beijing 100081, china 4. Division of Chemistry, Los Alamos National Laboratory, Los Alamos, NM 87544, USA 1. Department of earth sciences China University of Geosciences 430074 Wuhan China 2. Northeastern Illinois university 60625 Chicago IL USA 3. china Institute of Geo-Environmental Monitoring 100081 Beijing China 4. Division of Chemistry Los Alamos National Laboratory 87544 Los Alamos NM USA

The sorption of Eu species onto nano-size silica-water interfaces is investigated at pH range of 1―8.5 and the initial Eu concentrations (CEu) of 2 × 10?5, 2 × 10?4 and 2 × 10?3.M using fluorescence spectroscopy. The sorption rate of Eu is initially low, but significantly in-creases at pH > 4. For the initial CEu of 2 × 10?5, 2 × 10?4 and 2 × 10?3.M, the dissolved Eu spe-cies are completely sorbed onto silica-water interfaces at pH = 4.75, ~5.8 and 6.6, respectively, with the respective sorption densities of ~1.58 × 10?8, 1.58 × 10?7 and 1.58 × 10?6 mol/m2. The sorbed Eu species at pH 3., which is sorbed onto silica-water interfaces as an outer-sphere complex at pH 3.+ and Eu(CO3.2? form in the solutions, and Eu(CO3.+ is dominant at pH = ~7.5. These ions may be sorbed onto silica-water interfaces as inner-sphere bidentate complexes or multi-nuclear pre-cipitates.

关键词： surface sorption, Eu3. species, nano-size silica, fluorescence spectroscopy, immobilization of toxic metals

Origin of the Red earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science china earth sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2, JI Junfeg3. WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of earth Environment, Chinese Academy of sciences, Xi’an 710075, china 2. Department of Urban and Resources sciences, Nanjing university, Nanjing 210093. china 3. Department of earth sciences, Nanjing university, Nanjing 210093. china 4. Department of Geography, Shaanxi Normal university, Xi’an 710062, china 5. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 100029, china 6 Department of Geography, Qinghai Normal university, Xining 810008, china 7. Graduate School of the Chinese Academy of sciences, Beijing 10003., china 1. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 7. Graduate School of the Chinese Academy of sciences Beijing 100039 China 2. Department of Urban and Resources sciences Nanjing University Nanjing 210093 China 3. Department of earth sciences Nanjing University Nanjing 210093 China 4. Department of Geography Shaanxi Normal University Xi’an 710062 China 5. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 6. Department of Geography Qinghai Normal University Xining 810008 China

The Red earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red earth sequenceconsists of 25 visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red earth deposit is very fine-grained with anegligible sand fraction ( > 63.μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63.μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red earth *** REE distributions of the loess-soil and the Red earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the Redearth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.