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Uncertainty in magnetic activity indices

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Science china(Technological sciences) 2008年第10期51卷 1659-1664页

作者： XU WenYao institute of geology and Geophysics, {2. academy of sciences, beijing 10002., china institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Magnetic activity indices are widely used in theoretical studies of solar-terrestrial coupling and space weather prediction. However, the indices suffer from various uncertainties, which limit their application and even mislead to incorrect conclu-sion. In this paper we analyze three most popular indices, Kp, AE and Dst. Three categories of uncertainties in magnetic indices are discussed: "data uncertainty" originating from inadequate data processing, "station uncertainty" caused by in-complete station covering, and "physical uncertainty" stemming from unclear physical mechanism. A comparison between magnetic disturbances and related indices indicate that the residual Sq will cause an uncertainty of 1―2.in K meas-urement, the uncertainty in saturated AE is as much as 50%, and the uncertainty in Dst index caused by the partial ring currents is about a half of the partial ring cur-rent.

关键词： magnetic activity indices Kp AE Dst solar-terrestrial coupling space weather

Spectral analysis of quasi-stationary sea surface topography from GRACE mission

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Science china Earth sciences 2005年第11期48卷 2040-2048页

作者： ZHANG Zizhan1,2.& LU Yang1,3 1. institute of Geodesy and Geophysics, chinese {2. of sciences, Wuhan 430077, china 2. Graduate School of the chinese {2. of sciences, beijing 100039, china 3. Unite Center for Astro-geodymics Research, chinese {2. of sciences, Shanghai 2.0030, china 1. institute of Geodesy and Geophysics Chinese Academy of Sciences 430077 Wuhan China 2. Graduate School of the chinese academy of {2. 100039 Beijing China 3. Unite Center for Astro-geodymics Research Chinese Academy of Sciences 200030 Shanghai China

During the last two decades satellite altimetry has offered an abundance of meas-urements of the sea surface resulting in the improvement of global mean sea surface height (MSSH) and marine geoid determination. On the other hand, with the launching of new genera-tion gravity satellites, some high accuracy long-wavelength gravity models are available. These breakthroughs give us a great opportunity for new estimation of quasi-stationary sea surface topography (QSST). In this paper, the new gravity model GGM01C derived from GRACE mission is briefly presented, and a new global high precision and high-resolution QSST is determined based on the GGM01C model and the global MSSH. The spectral features of the QSST esti-mated by GGM01C and EGM96 gravity model to degree/order 2.0 are discussed by spectral analysis. As a result, the QSST is mainly composed of long waves, medium waves partially and short waves scarcely, its power spectral structures are different between the zonal direction and the meridional direction, there are great differences between the two models, which maybe ex-plain why the ocean currents derived from the two gravity models by Tapley show different pat-terns.

关键词： quasi-stationary sea surface topography, mean sea surface height, GGM01, fast Fourier transform, spectral analysis

Holocene grassland vegetation, climate and human impact in central eastern Inner Mongolia

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Science china Earth sciences 2005年第7期48卷 1025-1039页

作者： HUANG Fei1, Kealhofer Lisa2. XIONG Shangfa3 & HUANG Fengbao1 1. Nanjing institute of geology and Paleontology,{2. academy of sciences,Nanjing 2.0008,china 2. Anthropology and Sociology Department,Santa Clara University,CA 95053,USA 3. institute of geology and Geophysics,{2. academy of sciences,beijing 10002.,china Nanjing institute of geology and Paleontology Chinese Academy of Sciences Nanjing 210008 China Anthropology and Sociology Department Santa Clara University CA 95053 United States institute of geology and Geoohysics Chinese Academy of Sciences Beijina 100029 China

Phytolith and pollen preserved in the Taipusi Banner paleosol profile, central eastern Inner Mongolia, provide evidence of Holocene grassland vegetation, climate and human impact. The combined phytolith and pollen records reveal a major change in vegetation composition about 5000 a BP. Before 5000 a BP, the vegetation was dominated by Aneurolepidium chinese-Stipa grandis grassland of C4 grasses. After 5000 a BP, C4 grasses rapidly retreated, indicating a shift to colder and more arid conditions. The gradual invasion of Stipa krylovii, Ag-ropyron desertorum, Ephedra, Chenopodiaceae and Caragana reveal the onset of grassland degeneration. Between 10000 and 872. a BP, the Aneurolepidium chinese-Stipa grandis grassland included a small proportion of Artemisia shrub and Echionopos type plants, implying a strong winter monsoon and very weak summer monsoon. From 872. to 7000 a BP, C4 grasses were common, indicating a strengthening of the summer monsoon. Between 7000 and 5000 a BP, the Holocene thermal maximum was evident, with a significant expansion of C4 grasses and the presence of some trees (such as Pinus and Betula, and so on) in or near the study site. From 42.0?000 a BP, a sandy grassland of Artemisia and Agropyron desertorum together with Aster-type taxa occurred. Precipitation amelioration took place between 3000 and 2.70 a BP, with a rapid development of Echinops type plants and a small expansion of C4 grasses. From 2.70 a BP to present, human activities accelerated the process of grassland degeneration.

关键词： phytolith and pollen records grassland environment change human impact Holocene central eastern Inner Mongolia.

Grain-size features of a Miocene loess-soil sequence at Qinan: Implications on its origin

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Science china Earth sciences 2006年第7期49卷 731-738页

作者： QIAO Yansong1,3, GUO Zhengtang2.1, HAO Qingzhen1, YIN Qiuzhen1, YUAN Baoyin1 & LIU Tungsheng1 1. institute of geology and Geophysics, {2. academy of sciences, beijing 10002., china 2. institute of Earth Environment, {2. academy of sciences, Xi’an 710075, china 3. institute of Geomechanics, {2. academy of Geological sciences, beijing 100081, china 1. institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 3. institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China 2. institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

In this study, grain-size of 507 bulk samples from the QA-I Mioceneloess-soil sequence at Qinan were analyzed, and the grain-size features are compared with those oftypical Quaternary loess and soil samples, representative lacustrine and fluvial samples. Theresults indicate that the grain-size distribution pattern of the Miocene loess is essentiallysimilar to that of Quaternary loess, but greatly differs from the lacustrine and fluvial *** layers are regularly coarser than soil layers, indicating cyclical climate changes. Mediangrain-size along the 2.3.1 m sequence varies from 6 to 13 μm and the > 63 μm fraction representsonly 5.3% in maximum, 0.9% in average. Long-term grain-size variations are consistent with the loessaccumulation rate at Qinan and with the eolian mass accumulation rate in the North Pacific. Thesefeatures firmly indicate an eolian origin of the studied sequence, and also reveal a coeval changesbetween the long-term changes of eolian grain-size and continental aridity in the dust sourceregions.

关键词： Qinan, Miocene loess-soil sequence, grain-size, eolian origin.

Modeling and verifying Web services driven by requirements:An ontology-based approach

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Science in china(Series F) 2006年第6期49卷 792-820页

作者： HOU Lishan1,3,JIN ZHi1,2.& WU Budan1,4 1. academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, china 2. institute of Computing Technology, chinese academy of sciences, beijing 100080, china 3. institute of Software, chinese academy of sciences, beijing 100080, china 4. Graduate University of chinese academy of sciences, beijing 100049, china 1. academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China 3. institute of Software Chinese Academy of Sciences Beijing 100080 China 2. institute of Computing Technology Chinese Academy of Sciences Bejing 100080 China 4. Graduate University of chinese academy of {2. Beijing 100049 China

Automatic discovery and composition of Web services is an important research area in Web service technology, in which the specification of Web services is a key issue. This paper presents a Web service capability description framework based on the environment ontology. This framework depicts Web services capability in two aspects： the operable environment and the environment changes resulting from behaviors of the Web service. On the basis of the framework, a requirement-driven Web service composition model has been constructed. This paper brings forward the formalization of Web service interactions with π calculus. And an automatic mechanism converting conceptual capability description to the formal process expression has been built. This kind of formal specification assists in verifying whether the composite Web service model matches the requirement.

关键词： Web service environment ontology automatic composition π calculus formal verification.

Evaluation of the Interfacial Adhesion between Brittle Coating and Ductile Substrate by Cross-Sectional Indention

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材料热处理学报 2004年第5B期25卷 1187-1190页

作者： SUJian-yu ZHANGKun CHENGuang-nan instituteofMechanics ChineseAcademyofSciencesBeijingChina／／GraduateSchooloftheChineseAcademyofSciencesBeijingChina instituteofMechanics ChineseAcademyofSciencesBeijingChina

The cross-sectional indentation method is extended to evaluate the interfacial adhesion between brittle coating and ductile substrate. The experimental results on electroplated chromium coating/steel substrate show that the interfacial separation occurs due to the edge chipping of brittle coating. The corresponding models are established to elucidate interfacial separation processes. This work further highlights the advantages and potential of this novel indentation method.

关键词：分界面附着刻痕可锻衬底应力涂层铬钢

Structural and microstructural transformations in Bi_2.r_2.a_(1-x)Y_xCu_2._(8+y) system

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chinese Science Bulletin 1997年第3期42卷 192-196页

作者： SONG Chengyu, WEN Shulin and CHE Guangcan1. Shanghai institute of Ceramics, chinese {2. of sciences, Shanghai 2.0050, china 2. State Key Laboratory of Supercon-ductivity, institute of Physics, chinese {2. of sciences, beijing 100080, china Shanghai institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

SINCE the discovery of high-Tc superconductors, experiments have revealed that the phase diagrams of La2.xSrxCuO4 and YBa2.u3O6+x resemble each other. The antiferromagnetic phase is commonly situated in the vicinity o... 详细信息

SINCE the discovery of high-Tc superconductors, experiments have revealed that the phase diagrams of La2.xSrxCuO4 and YBa2./sub>Cu3O6+x resemble each other. The antiferromagnetic phase is commonly situated in the vicinity of the superconductive phase. In Bi-2.12.sys-

关键词： Bi2.r2.a1-xYxCu2.y substitution structural transformation.

Physical mechanisms of plant roots affecting weathering and leaching of loess soil

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Science china Earth sciences 2006年第9期49卷 1002-1008页

作者： LI Yong1,2. ZHANG Qingwen1,2. WAN Guojiang3, HUANG Ronggui3, PIAO Hechun3, BAI Lingyu2.& LI Lu2.1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, institute of Soil and Water Conservation, chinese {2. of sciences, Yangling 712.00, china 2. institute of Agro-Environment and Sustainable Development, chinese {2. of Agricultural sciences, beijing 100081, china 3. institute of Geochemistry, chinese {2. of sciences, Guiyang 550002. china 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling 712100 China 2. institute of Agro-Environment and Sustainable Development Chinese Academy of Agricultural Sciences Beijing 100081 China 3. institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Plant roots have potential impacts on soil mineral weathering and *** objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the chinese Loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 2..2. of the soil *** roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement > increase of bio-active substance > stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.

关键词： plant roots, soil weathering and leaching rates, soil environment field, principal components analysis (PCA), chinese Loess Plateau.

Geochemical simulation of the formation of brine and salt minerals based on Pitzer model in Caka Salt Lake

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Science china Earth sciences 2004年第8期47卷 720-726页

作者： LIU Xingqi1, CAI Keqin2.& YU Shengsong3 1. Nanjing institute of Geography and Limnology, chinese {2. of sciences, Nanjing 2.0008, china 2. china University of Geosciences, beijing 100083, china 3. institute of Salt Lakes, chinese {2. of sciences, Xining 810008, china 1. Nanjing institute of Geography and Limnology Chinese Academy of Sciences 210008 Nanjing China 2. china University of Geosciences 100083 Beijing China 3. institute of Salt Lakes Chinese Academy of Sciences 810008 Xining China

The geochemical simulation of the formation of brine and salt minerals based on Pitzer model was made in Caka Salt Lake. The evolution of the mixed surface-water and the mineral sequences were calculated and compared with the hydrochemical compositions of the brine and the salt minerals of the deposit in Caka Salt Lake. The results show that the formation temperature of the lake is between 0°C and 5°C, which is well identical with other studies. The mixing of salt-karst water with the surface waters, neglected by the former researchers, is very important to the formation of the lake, indicating that the initial waters resulting in the formation of the lake are multi-source. It is the first time to use Pitzer model in china for making geochemical simulation of the formation and evolution of inland salt lake and satisfactory results have been achieved.

关键词： Pitzer model,Caka Salt Lake,geochemical simulation,salt-karst water.