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Electrochemical Characterization of Surface-modified LiMn_2._4 Cathode Materials for Li-ion Batteries

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Journal of Wuhan university of technology(Materials Science) 2006年第4期21卷 56-59页

作者：禹筱元 College of Science South China Agricultural University Guangzhou 510642ChinaSchool of Physics & Engineering Sun Yat-sen University Guangzhou 510275China

To improve the performance, the surface of 12.n2.4 was coated with very fine MgO , Al2.3.and ZnO by solgel method, respectively. The structure and morphology of the coated materials were investigated by X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ） and scanning electron microscopy （SEM）. The charge and discharge performance of uncoated and surfnce modified 12.n2.4 spinel at 2.℃ and 55 ℃ were tested, using a voltage window of 3.0-4.3. V and a current deasity of 0. 1 C rate. There is a slight decrease in the initial discharge capacity relative to that of uncoated UMn2.O4, bat the cycle ability of 12.12.n2.4 coated by metal-oxide has remarkably been improved. The EIS measuremeuts of uncoated and Al2.3.-coated 12.n2.4 were carried out by a model 2.3.A potentiostatl galvanistat controUed by a computer using M2.0 software, and using a freqnency response analyzer （ Zsimpwin ） combined with a potentiostate （ PAR 2.3.. Coaseqnently, the reason for the improved cycle properties is that the surface modification reduces the dissolution of Mn , which results from the suppression of the electrolyte decomposition, and suppresses the formation of passivation film that acts as an electronic insulating layer. In conclusion, the use of surface modification is an effective way to improve the electrochemical performance of 12.n2.4 cathode material for lithium batteries.

关键词： lithium-ion batteries surface modification metal-oxide coating: 12.n2.4 cathode

A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

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Science china(Technological Sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2.& FENG Xueshang1,3.1. SIGMA Weather Group, Key Laboratory of Space Weather, Center for Space Science and applied Re-search, Chinese Academy of Sciences, Beijing 100080, china 2. Graduate {2. of the Chinese Academy of Sciences, Beijing 10003., china 3. {2. of Geophysics and Geoinformation Systems, china university of Geosciences, Beijing 100083. china 1. SIGMA Weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. Graduate school of the Chinese Academy of Sciences 100039 Beijing China 3. school of Geophysics and Geoinformation Systems China University of Geosciences 100083 Beijing China

Using 80 CME-ICME events during 1997.1―2.02.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2. The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. 3. The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 3.% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

Indian Ocean-MORB-type isotopic signature of Yushigou ophiolite in North Qilian Mountains and its implications

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Science china Earth Sciences 2006年第6期49卷 561-572页

作者： HOU Qingye1,2. ZHAO Zhidan1,2. ZHANG Hongfei3. ZHANG Benren3.& CHEN Yuelong2.1. State Key Laboratory of Geological Processes and Mineral Resources,{3. university of Geosciences, Beijing 100083.{3. 2. school of Earth Science and Mineral Resources,{3. university of Geosciences, Beijing 100083.{3. 3. Faculty of Earth Sciences,{3. university of Geosciences, Wuhan 43.074,{3. 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China 2. school of Earth Science and Mineral Resources China University of Geosciences Beijing 100083 China 3. Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China

In order to explore the disputed issue concerning the tectonic affinity ofthe ancient ocean mantle of North Qilian Mountains (NQM), geochemical and Sr, Nd, Pb isotopiccompositions of pillow basalts of the Yushigou Ophiolite (YSGO) suite from NQM have been analyzedsystematically. The pillow basalts exhibit tholeiitic characteristics, with flatchondrite-normalized REE patterns ((La/Yb)_N = 0.98—1.2.). They display no Nb, Ta, Zr, Hf negativeanomalies, and show MORB features in 2.b-Zr/4-Y and Ti/100-Zr-YX3.tectonic discrimination *** results indicate that the Yushigou ophiolite is most likely to be formed in a mid-ocean ridgeor mature back-arc basin. Their isotopic data show a relatively broad and enriched ^(87)Sr/^(86)Sr(0.70509 — 0.70700), restricted ^(143.Nd/^(144)Nd (0.512.55-0.512.78). Pb isotopes are in the rangeof ^(2.6)Pb/^(2.4)Pb (18.054-2..562., ^(2.7)Pb/^(2.4)Pb (15.53.-15.743. and ^(2.8)Pb/^(2.4)Pb(3..068-3..53.). These isotopic data imply that the basalts originated from the depleted mantle(DMM), with the involvement of enriched mantle components (mainly EMII). Geochemical comparisonsbetween the basalts in YSGO and the MORB-type basalts of ophiolite suites occurring in the knownancient Tethyan tectonic domain indicate that the ancient oceanic mantle represented by YSGO suiteforming in early Paleozoic in the North Qilian Moutains is very similar to the Tethyan mantle inboth trace elements and isotopic compositions. The North Qilian Mountains should be a part of theTethyan tectonic domain in early Paleozoic. This further implies that the Tethyan tectonic domaincan be deduced to early Paleozoic in the study area, which will be helpful to discussing thetectonic affinity and evolution of the North Qilian Mountains.

关键词： geochemistry, Indian Ocean-MORB-type isotopic signatures, Tethyan tectonic domain, Yushigou ophiolite, North Qilian Mountains.

Mechanism of Breakdown in Laminar-Turbulent Transition of Incompressible Boundary Layer on a Flat Plate

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Transactions of Tianjin university 2007年第2期13卷 79-87页

作者：唐洪涛罗纪生周恒 school of Mechanical Engineering Tianjin University

Temporal mode direct numerical simulation was done for the process of laminar-turbulent transition in an incompressible boundary layer on a flat plate. The analysis of the results showed that during the breakdown process of laminar-turbulent transition, the modification of the mean flow profile by the disturbances led to a remarkable change in its stability characteristics, manifested in the significant enlargement of the linear unstable zone and the maximum amplification rate, and led to that many more disturbances were excited and enhanced rapidly, correspondingly the turbulent energy also increased rapidly, and the mean flow profiles evolved swiftly from laminar to turbulent. It was also found that if the oblique waves in the initial disturbances did not form symmetrical pairs, the subsequent span-wise mean velocities would, in general, be nonzero due to nonlinear interaction, which would have a great effect on the stability characteristics and also implied that the turbulence obtained by direct numerical simulation might not be fully a random process.

关键词： boundary layer transition direct numerical simulation breakdown

Electron microscopy study of the sakhaite from endogenous borate deposit in Hunan, china

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Science china Earth Sciences 2004年第3期47卷 232-238页

作者： LIU Xiangwen1,2. YANG Guangming2. ZOU Huamin3. QU Jing1 & ZHAO Wenxia4 1. Graduate school,{3. {2. of Geosciences, Wuhan 43.074,{3. 2. Test Center,{3. {2. of Geosciences, Wuhan 43.074,{3. 3. Physics and technology College, Wuhan {2., Wuhan 43.072.{3. 4. Test Center, Zhongshan {2., Guangzhou 5102.5,{3. china Univ Geosci Grad Sch Wuhan 430074 Peoples R China china Univ Geosci Test Ctr Wuhan 430074 Peoples R China Wuhan Univ Phys & Technol Coll Wuhan 430072 Peoples R China Zhongshan Univ Test Ctr Guangzhou 510275 Peoples R China

Sakhaite specimens from an endogenous borate deposit in Hunan Province, china have been studied in detail by means of transmission electron microscopy (TEM). The selected area electron diffraction (SAED) patterns obtained with different crystal zone axes show that the crystal system is cubic, with a = 1.463.nm. The convergent beam electron diffraction (CBED) patterns indicate that the point group and space group of sakhaite is m3. and Fd3., respec-tively. The space group of synthetic sakhaite determined by Chichagov (1974) is F413.1} The possible reasons why the space groups of the natural and the synthetic sakhaites are different are discussed.

关键词： sakhaite, space group, convergent beam electron diffraction (CBED).

CO observations of massive star forming regions at different evolutionary phases

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEN Xi1,2. XU Ye1,3. SHEN Zhiqiang1,3.& LI Jingjing1,2.1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 2.003.,{3. 2. Graduate school of the Chinese Academy of Sciences, Beijing 10003.,{3. 3. Joint Institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the university of Science and technology of{3., Shanghai 2.003.,{3. Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate school of the Chinese Academy of Sciences Beijing 100034 China Joint Institute for Galaxy Cosmology Shanghai Astronomical Observatory the university of Science technology of china Shanghai 200030 China

The 12.O (J=1-0), 13.O (J=1-0) and C18O (J=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13.O cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2. masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 2.566+582. in the observing field of S152.S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2. maser simulta- neously.

关键词： star formation cloud core outflow H2. maser

Prediction of Tumor Outcome Based on Gene Expression Data

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Wuhan university Journal of Natural Sciences 2004年第2期9卷 177-182页

作者： Liu Juan 1,2. Hitoshi Iba 3.1. school of Computer, Wuhan university, Wuhan 43.072. Hubei,{2. 2. State Key Laboratory of Software Engineering, Wuhan 43.072. Hubei,{2. 3. Department of Frontier Informatics, university of Tokyo, Tokyo 113.8656, Japan Wuhan university School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) State Key Laboratory of Software Engineering Wuhan Hubei China (GRID:grid.49470.3e) university of Tokyo Department of Frontier Informatics Tokyo Japan (GRID:grid.26999.3d) (ISNI:***)

Gene expression microarray data can be used to classify tumor types. We proposed a new procedure to classify human tumor samples based on microarray gene expressions by using a hybrid supervised learning method called MOEA+WV (Multi-Objective Evolutionary Algorithm+Weighted Voting). MOEA is used to search for a relatively few subsets of informative genes from the high-dimensional gene space, and WV is used as a classification tool. This new method has been applied to predicate the subtypes of lymphoma and outcomes of medulloblastoma. The results are relatively accurate and meaningful compared to those from other methods. Key words bioinformatics - tumor classification - Pareto optimization - MOEA CLC number Q 786 - TP 181 Foundation item: Supported by the National Natural Science Foundation of china (603.1009), the Foundation of Young Scholars of Ministry of Education of china (150118) and Chenguang Project of Wuhan City ({3.11{3.009).Biography: Liu Juan (1970-), female, Associate Professor, Postdoctoral, research direction: bioinformatics, data mining, machine learning.

关键词： bioinformatics tumor classification Pareto optimization MOEA

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine

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Journal of Wuhan university of technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

COLLECTIVELY COMPACT COMPOSITION OPERATOR SEQUENCES BETWEEN BERGMAN AND HARDY SPACES

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Acta Mathematica Scientia 2004年第2期24卷 206-212页

作者：王茂发刘培德 schoolofMathematicsandStatistics WuhanUniversityWuhan430072China

This paper studies the collective compactness of composition operator sequences between the Bergman and Hardy spaces. Some sufficient and necessary conditions involving the generalized Nevanlinna counting functions fo... 详细信息

关键词： Bergman space Hardy space composition operator collectively compact operator sequence