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Geometric construction of energy-minimizing Bézier curves

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science china(Information sciences) 2011年第7期54卷 1395-1406页

作者： XU Gang 1,4,5,WANG GuoZhao 2 & CHEN WenYu 2,3.1 Institute of Graphics and Image,Hangzhou Dianzi university,Hangzhou 3.0018,china 2 Department of mathematics,Zhejiang university,Hangzhou 3.0027,china 3.School of Computer Engineering,Nanyang Technological university,63.798,Singapore 4 Galaad,INRIA Sophia-Antipolis,2004 Route des Lucioles,06902,France 5 State Key Lab of CAD & CG,Zhejiang university,Hangzhou 3.0027,china Institute of Graphics and Image Hangzhou Dianzi University Hangzhou China Galaad INRIA Sophia-Antipolis Sophia Antipolis France State Key Lab of CAD & CG Zhejiang University Hangzhou China Department of mathematics Zhejiang University Hangzhou China School of Computer Engineering Nanyang Technological University Singapore Singapore

Modeling energy-minimizing curves have many applications and are a basic problem of Geometric *** this paper,we propose the method for geometric design of energy-minimizing B′ezier ***,the necessary and sufficient condition on the control points for B′ezier curves to have minimal internal energy is *** on this condition,we propose the geometric constructions of three kinds of B′ezier curves with minimal internal energy including stretch energy,strain energy and jerk *** some control points,the other control points can be determined as the linear combination of the given control *** compare the three kinds of energy-minimizing B′ezier curves via curvature combs and curvature plots,and present the collinear properties of quartic energy-minimizing B′ezier *** also compare the proposed method with previous methods on efficiency and ***,several applications of the curve generation technique,such as curve interpolation with geometric constraints and modeling of circle-like curves are discussed.

关键词： curve design minimal energy geometric construction interpolation with constraints circle-like curves

Synthesis and Luminescence Properties of Red Phosphor CaO:Eu^(3.)

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Journal of Wuhan university of technology(Materials science) 2009年第1期24卷 20-24页

作者：康明 School of Material science and Engineering Southwest University of Science and Technology College of Materials science and Engineering Sichuan University

Ca（NO3.2·4H2O, Eu（NO3.3.and H2C2O4·2H2O were adopted to synthesize CaO： Eu3. with the chemical co-precipitation method, and the effects of the calcination temperature and Eu3. doping concentration on the phosphor structure and its luminescent properties were investigated by TG-SDTA, XRD, and PL-PLE. The results confirm that the Eu3. ions as luminescent centers substi-tutes Ca2＋ sites without changing the crystal structure of cubic CaO. The optimum calcination tem-perature and the optimum concentration of Eu3. are 1 100 ℃ and 1 mol%, respectively, under which the best crystallinity and highest PL intensity appeared. The maximum emission wavelength is 592 nm （5D0→7F1） which is excited by xenon lamp with the wavelength of 200-280 nm, indicating that the Eu3. ion mainly locates in the symmetric position （Oh） in the crystal lattice of CaO.

关键词： red phosphor CaO Eu^3. co-precipitation method rare earths

The Class of the Generalized αk-Major Efficient Solutions for Multi-objective Programming

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Journal of Systems science and Systems Engineering 2001年第4期13卷 439-442页

作者： XU Ze-shui Institute of sciences, PLA university of science and {3., Nanjing 210016, Jiangsu, china Institute of sciences PLA University of Science and TechnologyNanjing 210016 Jiangsu China

This paper proposes the concepts of generalized αk-major efficient solutions and generalized αk- major optimal solutions for multi-objective programming, and studies their some important properties.

关键词： multi-objective programming generalized αk-major efficient solutions generalized αk-major optima1 solutions

Improving the Wear Resistance of AZ3.B Magnesium Alloy by Laser Cladding with Al-Si/Al_2O_3.TiO_2 Powders

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稀有金属材料与工程 2011年第S4期40卷 169-173页

作者： Cui Zeqin1,2,Wang Wenxian1,2,Wu Hongliang1,Xu Bingshe1,2 1Key Laboratory of Interface science and Engineering in Advanced Materials (Taiyuan university of technology),Ministry of Education,Taiyuan 03.024,{3. 2College of Materials science and Engineering,Taiyuan university of technology,Taiyuan 03.024,{3. Taiyuan Univ Technol Coll Mat Sci & Engn Taiyuan 030024 Peoples R China Taiyuan Univ Technol Minist Educ Key Lab Interface Sci & Engn Adv Mat Taiyuan 030024 Peoples R China

To improve the wear resistance of magnesium alloy,the laser surface cladding of AZ3.B magnesium alloy with Al-12 % Si and Al2O3.40 % TiO2 composite powders (in the wt.% ratio of 10:1,6:1,4:1) were investigated by using a 5kW continuous wave CO2 laser.A detailed microstructure and phase analysis of the surface modified layer were studied by optics microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy (EDS),X-ray diffraction(XRD).The microstructure of the surface modified layers mainly consist of Al-Mg matrix,dendrite precipitates and Al2O3.TiO2 ceramic *** microhardness of the surface layer were measured and wear resistance property were evaluated in *** average microhardness of the surface layers were significantly improved to 250HV0.05 as compared with 50HV0.05 of the AZ3.B *** results showed that the wear resistance of the laser surface modified samples was considerably improved as compared as the as-received specimen.

关键词： AZ3.B magnesium alloy laser cladding Al-Si/Al2O3.TiO2 powders wear resistance

Exploring the deep biosphere

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science china Earth sciences 2011年第2期54卷 157-165页

作者： FANG JiaSong1,2 & ZHANG Li3.1 State Key Laboratory of Marine Geology, Tongji university, Shanghai 200092, china 2 College of Natural and Computational sciences, Hawaii Pacific university, Kaneohe, HI 96744, USA 3.State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth sciences, china university of Geosciences, Wuhan 43.074, china State Key Laboratory of Marine Geology Tongji University Shanghai China College of Natural and Computational sciences Hawaii Pacific University Kaneohe USA State Key Laboratory of Geological Processes and Mineral Resources Faculty of Earth Sciences China University of Geosciences Wuhan China

Over the past two decades, scientific drilling into sediments and rocks in the ocean and the continent has revealed the presence of physiologically and phylogenetically complex microbial life in the deep subsurface. Microorganisms, most of which have no cultured or known relatives in the surface biosphere, have been discovered in sediments and rock at depth as deep as 1 km below the seafloor and more than 3.km deep in the continent. The deep biosphere probably represents the most voluminous part of the global biosphere and may constitute as much as 50% of the Earth’s biomass. In this article, we review the current knowledge of and most recent advances in studying the deep biosphere and suggest directions in future research.

关键词： deep biosphere Thomas Gold microorganism biomass DNA ribosome ODP CARD-FISH dark energy lipids serpentinization

Electronic Structure and Thermoelectric Properties of Ca_3.o_4O_9

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Journal of Wuhan university of technology(Materials science) 2006年第1期21卷 13-15页

作者：闵新民 Department of Applied Chemistry Wuhan University of TechnologyWuhan 430070China

The relation among electronic structure, chemical bond and thermoelectric property of Ca3.Co4 O9 was studied using density function and discrete variation method （DFT-DVM）. The gap between the highest valence band （HVB） and the lowest conduction band （LCB） shows a semiconducting property. Ca3.Co4 O9 consists of CoO2 and Ca2 CoO3.two layers. The HVB and LCB near Fermi level are only mainly from O（ 2 ） 2p and Co （2） 3. in Ca2 CoO3.layer. Therefore, the semiconducting or thermoelectric property of Ca3.Co4 O9 should be mainly from Ca2 CoO3.layer, but it seems to have no direct relation to the CoO2 layer, which is consistent with that binary oxides hardly have a thermoelectric property, but trinary oxide compounds have quite a good thermoelectric property. The covalent and ionic bonds of Ca2 CoO3.layer are both weaker than those of CoO2 layer. Ca plays the role of connections between CoO2 and Ca2 CoO3.layers in Ca3.Co4 O9, decrease the ionic and covalent bond strength, and improve the thermoelectric property.

关键词： cobaltite electronic structure chemical bond thermoelectric property

Coupling Losses and Discrimination of Annular Waveguide Laser Resonators

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Chinese Journal of Lasers 1999年第2期8卷 14-20页

作者： WANG Youqing HUANG Xintang CHEN Q. M. QIU J. L. XU Q. Y. (National Lab. of Laser technology, Huazhong university of science and technology, Wuhan 43.074, china) 华中理工大学激光技术国家重点实验室湖北武汉 430074 华中理工大学激光技术国家重点实验室湖北武汉

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关键词： coupling loss annular waveguide laser toric mirror

INFLUENCE OF SEEPAGE FACE OBLIQUITY ON DISCHARGE OF GROUNDWATER AND ITS POLLUTANT INTO LAKE FROM A TYPICAL UNCONFINED AQUIFER

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Journal of Hydrodynamics 2007年第6期19卷 756-761页

作者： LI Yong WANG Chao YANG Lin-zhang LI Yi-ping State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing 210098 China College of Environmental science and Engineering Hohai University Nanjing 210098 China Institute of Soil science Chinese Academy of Sciences Nanjing 210008 China

Lab experiment and mathematical simulation Modular three dimensional finite difference groundwater （MODFLOW） were performed in a soil tank to simulate the hydrogeochemical interaction between lake and typical unconfined aquifer. Results show that the velocity decreases exponentially with the transect distance on seepage face. The maximal velocity occurs at the top point of seepage face. The obliquity of seepage face has a great influence on the maximum and distribution of seepage velocity. With the increase of the obliquity of seepage face, the maximal velocity decreases quickly and the velocity distribution becomes much more even. Most of groundwater flow and pollutant flux discharges through a narrow portion near the top of seepage face. The flow and mass concentrated in the narrow portion increase with the decrease of the obliquity of seepage face. These will benefit to design a reasonable and economical scenario to manage lakeshore and to control the pollution of lake water near lakeshore.

关键词： shallow lake unconfined aquifer groundwater discharge velocity distribution chloride MODFLOW

Search recommendation model based on user search behavior and gradual forgetting collaborative filtering strategy

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The Journal of china Universities of Posts and Telecommunications 2010年第3期17卷 110-117页

作者： LIU Chuan-chang State Key Laboratory of Networking and Switching technology, Beijing university of Posts and Telecommunications, Beijing 100876, china State Key Laboratory of Networking and Switching technology Beijing University of Posts and Telecommunications Beijing 100876 China

The existing search engines are lack of the consideration of personalization and display the same search results for different users despite their differences in interesting and purpose. By analyzing user＇s dynamic search behavior, the paper introduces a new method of using a keyword query graph to express user＇s dynamic search behavior, and uses Bayesian network to construct the prior probability of keyword selection and the migration probability between keywords for each user. To reflect the dynamic changes of the user＇s preference, the paper introduces non-lineal gradual forgetting collaborative filtering strategy into the personalized search recommendation model. By calculating the similarity between each two users, the model can do the recommendation based on neighbors and be used to construct the personalized search engine.

关键词： search recommendation model search behavior expression keyword query graph gradual forgetting collaborative filtering