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science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 856-863页

作者： CAI Xin1,2.LIU JinSong1 & WANG ShengLie1 1 wuhan National Laboratory for Optoelectronics,school of Optoelectronic {2. and Engineering,Huazhong university of {2. and Technology,wuhan 430074,china 2.school of science,wuhan university of Technology,wuhan 4.0070,china wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and Engineering Huazhong University of Science and Technology Wuhan China school of science Wuhan University of Technology Wuhan China

The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and *** the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams *** accordance with these results,the state of two Gaussian waves mixing is controllable.

关键词： numerical simulation experimental investigation two-wave mixing transverse effects Gaussian distribution

Hierarchical Classification of Chinese Documents Based on N grams

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wuhan university Journal of Natural {2.s 2001年第Z1期6卷 416-422页

作者： Zhou Shui geng 1, Guan Ji hong 2. He Yan xiang 2.1. State Key Laboratory of Software Engineering, wuhan university, wuhan 430072. china 2. school of Computer science, wuhan university, wuhan 430072. china State Key Laboratory of Software Engineering Wuhan University Wuhan China school of Computer science Wuhan University Wuhan China

We explore the techniques of utilizing N gram information to categorize Chinese text documents hierarchically so that the classifier can shake off the burden of large dictionaries and complex segmentation processing, and subsequently be domain and time independent. A hierarchical Chinese text classifier is implemented. Experimental results show that hierarchically classifying Chinese text documents based N grams can achieve satisfactory performance and outperforms the other traditional Chinese text classifiers.

关键词： Chinese text classification N grams feature selection hierarchical classification

Early Age Compressive Strength of Pastes by Electrical Resistivity Method and Maturity Method

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Journal of wuhan university of Technology(Materials {2.) 2011年第5期26卷 983-989页

作者：肖莲珍 school of Materials science and Engineering Wuhan Institute of Technology

The compressive strength development of Portland cement pastes was investigated by the electrical resistivity method and the maturity *** experiments were carried out on the cement pastes with different water-cement ratios at different curing *** results show that the application of the maturity method has limitation to obtain the *** is found that both of the compressive strength and the electrical resistivity follow hyperbolic trend for all the *** hyperbolic equation of each mix is obtained to estimate the ultimate resistivity value which can probably be *** relationship between electrical resistivity and compressive strength of the cement pastes is established based on the test results and interpreted by the empirical Archie equation and a strength-porosity *** relationship between the electrical resistivity after temperature correction and the compressive strength was linear and independent of curing temperature and water-cement ratio.

关键词： electrical resistivity cement hydration compressive strength maturity method

A Principal Theorem of Normal Discretization Schemes for Operator Equations of the First Kind

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wuhan university Journal of Natural {2.s 2001年第4期6卷 767-768页

作者： Du Nai lin 1, Wang Hannah 2.1.school of Mathematics and Statistics, wuhan {2., wuhan 430072. china 2. school of Foreign Languages and Literature,wuhan {2.,wuhan 430072.china school of Mathematics and Statistics Wuhan University Wuhan China school of Foreign Languages and Literature Wuhan University Wuhan China

The authors announce a newly-proved theorem of theirs. This theorem is of principal significance to numerical computation of operator equations of the first kind.

关键词： operator equation of the first kind normal discretization scheme pure pseudoinverse

Evaluation Method of Web Site Structure Based on Web Structure Mining

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wuhan university Journal of Natural {2.s 2003年第3A期8卷 791-796页

作者： Li Jun\|e 1 , Zhou Dong\|ru 2.1. Computer Center,wuhan university, wuhan 430072. Hubei, china 2. school of Computer,wuhan university, wuhan 430072. Hubei,china Computer Center Wuhan University Wuhan Hubei China school of Computer Wuhan University Wuhan Hubei China

The structure of Web site became more complex than before. During the design period of a Web site, the lack of model and method results in improper Web structure, which depend on the designer's experience. From the point of view of software engineering, every period in the software life must be evaluated before starting the next period's work. It is very important and essential to search relevant methods for evaluating Web structure before the site is completed. In this work, after studying the related work about the Web structure mining and analyzing the major structure mining methods (Page\|rank and Hub/Authority), a method based on the Page\|rank for Web structure evaluation in design stage is proposed. A Web structure modeling language WSML is designed, and the implement strategies for evaluating system of the Web site structure are given out. Web structure mining has being used mainly in search engines before. It is the first time to employ the Web structure mining technology to evaluate a Web structure in the design period of a Web site. It contributes to the formalization of the design documents for Web site and the improving of software engineering for large scale Web site, and the evaluating system is a practical tool for Web site construction.

关键词： web structure mining page\|rank web structure evaluation modeling language for web structure

Piezoresistivity of Carbon Fiber Graphite Cement-based Composites with CCCW

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Journal of wuhan university of Technology(Materials {2.) 2011年第2期26卷 340-344页

作者：范晓明 school of Materials science and Engineering Wuhan University of Technology

The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were *** experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation *** percolation threshold was about 2.%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,2.wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain *** measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 2.wt% and 30wt% were 37 and 2.,*** the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.

关键词： carbon fiber graphite cement-based composites cementitious capillary crystalline waterproofing materials electrical resistivity piezoresistivity

Minimal systems of generators for central division algebra and semi-simple algebra

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Chinese science Bulletin 1998年第21期43卷 1777-1780页

作者： QIU Qizhang 1 and SUN Ling 2.1. Department of Mathematics, wuhan university, wuhan 430072. china 2. Department of Information science, wuhan university, wuhan 430072. china. Department of Mathematics Wuhan University Wuhan China Department of Information science Wuhan University Wuhan China

Suppose that F is a field of characteristic zero and (ⅰ) D is a finite-dimensional central division algabra over F; (ⅱ) A is a finite-dimensional semi-simple algabra over F. It is proved that as F-algebras, D and A ... 详细信息

关键词： central division algebra semi-simple algebra generator minimal system of generators.

Electrically Conductive Concrete for Heating Using Steel Bars as Electrodes

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Journal of wuhan university of Technology(Materials {2.) 2010年第3期25卷 523-526页

作者：侯作富 school of Mechanical Engineering Yangtze University

The steel bars with good electrical conductivity were used as two kinds of electrodes in the making of carbon fiber（CF） electrically conductive concrete for *** results of the pertinent experiments illustrate the design is *** change in electrical resistivity over three years＇ hydration time was studied when steel bars were used as lateral face electrodes and top bottom surface electrodes *** temperature rise test was conducted to verify the heating properties of two kinds of *** only the study can reduce the CF volume content of electrically conductive concrete for heating to 0.58% or 0.36% according to different design,but also it will enhance the carrying capacity of the concrete roadway for heating.

关键词： steel bar carbon fiber electrical resistivity temperature rise

Seabed Classification Using BP Neural Network Based on GA

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Acta Oceanologica Sinica 2003年第4期22卷 523-531页

作者： Yang Fanlin1, Liu Jingnan2.1. GPS Engineering Research Center, wuhan university, wuhan 430079, china. 2. Presidential Secretariat, wuhan university, wuhan 430079, china GPS Engineering Research Center Wuhan University Wuhan 430079 China Presidential Secretariat Wuhan University Wuhan 430079 China

Side scan sonar imaging is one of the advanced methods for seabed study. In order to be utilized in other projects, such as ocean engineering, the image needs to be classified according to the distributions of different classes of seabed materials. In this paper, seabed image is classified according to BP neural network, and. Genetic Algorithm is adopted in train network in this paper. The feature vectors are average intensity, six statistics of texture and two dimensions of fractal. It considers not only the spatial correlation between different pixels, but also the terrain coarseness. The texture is denoted by the statistics of the co-occurrence matrix. Double Blanket algorithm is used to calculate dimension. Because a uniform fractal may not be sufficient to describe a seafloor, two dimensions are calculated respectively by the upper blanket and the lower blanket. However, in sonar image, fractal has directivity, i. e. there are different dimensions in different direction. Dimensions are different in acrosstrack and alongtrack, so the average of four directions is used to solve this problem. Finally, the real data verify the algorithm. In this paper, one hidden layer including six nodes is adopted. The BP network is rapidly and accurately convergent through GA. Correct classification rate is 92.5 % in the result.

关键词： BP network co-occurrence matrix fractal classification genetic algorithin

Electronic Structure of Doped Trans-Polyacetylene

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wuhan university Journal of Natural {2.s 2002年第1期7卷 51-53页

作者： Ren Da-zhi 1,2. Zhuang Wei 2. Wang Jun 2.1. wuhan university Journals Press,wuhan 430072.Hubei,china 2. school of Physics and Technology, wuhan university, wuhan 430072.Hubei,china wuhan university Journals Press Wuhan Hubei China school of Physics and Technology Wuhan University Wuhan Hubei China

The behavior of electronic structures of doped trans-polyacetylene is revealed by a simple method. (C2.H2.)+n is used to simulate p-type doped trans-polyacetylene at various doping concentrations. The electronic structure is calculated, by CNDO/2.method. These calculations show that at low doping level, the decrease of electronic energy compensates the increase of elastic energy, thus the bond alternation exists, and the charge carriers are solitons. When doping level is high, the increase of elastic energy is larger than the decrease, of electronic energy, the bond alternation disappears, solitons no longer exist, and polyacetylene is in a metalic state.

关键词： trans polyacetylene CNDO/2 electronic structure doped