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Dynamic behavior of polymer surface and the time dependence of contact angle

science china Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & SHEN Zhiquan2.1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, department of Applied Chemistry, zhejiang Institute of {2. and Technology, hangzhou 310033, china 2. department of polymer {2. and Engineering, zhejiang university, hangzhou 31002., china 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of polymer {2. and Engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

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Synthesis and crystal structure of complex of Ce(NO_3)_3 with N-(3-methyl-pyridin-2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone

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science china Chemistry 2004年第3期47卷 251-256页

作者： JIANG Yinzhi1,2.& HU Weixiao1 1. department of Pharmaceutical science,{2. of Technology, hangzhou 310032. china 2. department of Applied Chemistry, zhejiang Institute of science and Technology, hangzhou 310033, china 1. department of Pharmaceutical science Zhejiang University of Technology 310032 Hangzhou China 2. department of Applied Chemistry Zhejiang Institute of Science and Technology 310033 Hangzhou China

The reaction of 3,6-di-(3-methyl-pyridin-2.yI)-s-tetrazine (DMPTZ, II) with CeIII salt [Ce(NO3)3 · 6H2.] generates a new ligand, N-(3-methyl-pyridin-2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone (L), and forms a new complex: a mononuclear complex [Ce(L)(NO3)2.(H2.)3] · NO3 (III). Crystal data for III: space group P-1, with a = 0.7133(4) nm, b = 1.1139(2. nm, c = 1.4572.3) nm, α= 102.13(2.°, β= 99.81(3)°, γ= 91.10(3)°, Z = 2. V = 1113.6(7) nm3, μ = 2.12. mm?1 and F(000) = 630. L acts as a tri-dentate chelating ligand in III. There are 10 coordination sites around Ce3+ of III, which are respectively occupied by seven oxygen atoms (four from two nitrate anions and three from three H2. molecules) and three nitrogen atoms (all from L). The cerium atom and three chelating nitrogen atoms are coplanar. The mechanism of the metal assisted decomposition is discussed briefly.

关键词： rare earth, complex, crystal structure, synthesize, 3,6-bis (3-methyl-pyridin-2.yl)-s-tetrazine, N-(3-methyl-pyridin- 2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone.

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Shape blending of artistic brushstroke represented by disk B-spline curves

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Progress in Natural science:Materials International 2007年第12期17卷 1501-1507页

作者： Cheng Min1,2.and Wang Guojin1(1. department of Mathematics, zhejiang university,{2., china 2. department of Mathematics, zhejiang university of Technology, hangzhou 310032. china) department of Mathematics Zhejiang University Hangzhou 310027 China 2. department of Mathematics Zhejiang University of Technology Hangzhou 310032 China

This paper presents an algorithm for automatically generating in-between frames of two artistic brushstrokes. The basic idea of the algorithm is to represent the two key frames of artistic brushstrokes in disk B-spline curves, and then make blending of their geometric intrinsic variables. Given two key frames of artistic brushstrokes, the skeleton curves can be obtained by certain skeleton-based techniques. After disk B-spline representation of the key frames is generated, interpolation of the intrinsic variables of the initial and the target disk B-spline curves is carried out. Examples show that this method can efficiently create in-between frames of artistic brushstrokes.

关键词： computer aided calligraphy shape blending brushstroke disk B-spline curve skeleton.

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Lipschitz continuity of best approximations and Chebyshev centers

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Chinese science Bulletin 1998年第3期43卷 185-188页

作者： LI Chong 1 and WANG Xinghua 2.1. Center for Mathematical sciences, zhejiang university,{2., china 2. department of Mathematics, hangzhou university,{2., china Center for Mathematical sciences Zhejiang University Hangzhou China department of Mathematics Hangzhou University Hangzhou China

The Lipschitz continuity results are given for best approximations and Chebyshev centers. Consequently, the open problem presented by Septycki and Vleck is solved completely.

关键词： best approximation Chebyshev center uniform convexity.

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Perturbations of the radical of nest algebras

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Chinese science Bulletin 1998年第7期43卷 556-560页

作者： LU Fangyan 1 and LU Shijie 2.1. department of Mathematics, Suzhou university, Suzhou 2.5006,{2. 2. department of Mathematics, zhejiang university, hangzhou 31002.,{2. department of Mathematics Suzhou University Suzhou China department of Mathematics Zhejiang University Hangzhou China

Let R N and K-N be the radical ideal and the compact operator ideal of nest algebra T(N) respectively. It is proved thatR-N+K-N=span{T∈T(N)∶TT(N)NCT}=span{T∈T(N): #σ′(ST)≤1, S∈T(N)}.

关键词： nest algebras radical perturbation.

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Electro-mechanical response of functionally graded beams with imperfectly integrated surface piezoelectric layers

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science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 513-525页

作者： YAN Wei1 & CHEN Weiqiu1,2.1. department of Civil Engineering, zhejiang university,{2., china 2. State Key Lab of CAD & CG, zhejiang university,{2., china 1. department of Civil Engineering Zhejiang University Hangzhou 310027 China 2. State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

The time-dependent behavior of a simply-supported functionally graded beam bonded with piezoelectric sensors and actuators is studied using the state-space method. The creep behavior of bonding adhesives between piezoelectric layers and beam is characterized by a Kelvin-Voigt viscoelastic model, which is practical in a high temperature circumstance. Both the host elastic functionally graded beam and the piezoelectric layers are orthotropic and in a state of plane stress, with the former being inhomogeneous along the thickness direction. A laminate model is employed to approximate the host beam. Moreover, the coupling effect between the elastic deformation and electric field in piezoelectric layers is considered. Results indicate that the viscoelastic property of interfacial adhesives has a significant effect on the function of bonded actuators and sensors with time elapsing.

关键词： functionally graded beam piezoelectric layers Kelvin-Voigt model state-space method

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Online uniform machine covering with the known largest size

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Progress in Natural science:Materials International 2007年第11期17卷 1271-1278页

作者： Cao Shunjuan1,2.and Tan Zhiyi1,3(1. department of Mathematics, zhejiang university,{2., china 2. department of Mathematics, zhejiang Forestry university, hangzhou 311300, china 3. State Key Laboratory of CAD & CG, zhejiang university,{2., china) department of Mathematics Zhejiang University Hangzhou 310027 China department of Mathematics Zhejiang Forestry University Hangzhou 311300 China State Key Laboratory of CAD & CG Zhejiang University Hangzhou 310027 China

This paper investigates the semi-online scheduling problem with the known largest size on two uniform machines. The objective is to maximize the minimum machine completion time. Both lower bounds and algorithms are given. Algorithms are optimal for the majority values of s≥1, where s is the speed ratio of the two machines. The largest gap between the competitive ratio and the lower bound is about 0.064. Moreover, the overall competitive ratio 2.matches the overall lower bound.

关键词： scheduling and covering uniform machine design and analysis of algorithm online competitive ratio

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Effects of Ca substitution and surface treatment on electrochemical performances of Ml_(1.0-x) Ca_xNi_(4.0) Co_(0.6) Al_(0.4) hydrogen storage alloy electrodes

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中国有色金属学会会刊：英文版 1999年第3期9卷 487-492页

作者： Chen Weixiang(陈卫祥) 1, Qi Jianqin(祁建琴) 1, Chen Changpin(陈长聘) 2.1. department of Physics 2. department of Materials {2. and Engineering, zhejiang university, hangzhou 31002., P. R. china zhejiang Univ Dept Phys Hangzhou 310027 Peoples R China zhejiang Univ Dept Mat Sci & Engn Hangzhou 310027 Peoples R China

The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 2.for Ml could improve its discharge capacity, but Ca substitution with x >0.2.could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02.mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. :The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 2.for Ml could improve its discharge capacity, but Ca substitution with x >0.2.could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02.mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode.

关键词： hydrogen storage alloy electrode Ca substitution surface modification

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Planar cubic hybrid hyperbolic polynomial curve and its shape classification

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Progress in Natural science:Materials International 2004年第1期14卷 42-47页

作者： WANG Guozhao 1,2. * and YANG Qinmin 1,2. (1. Institute of Computer Graphics and Image Processing, 2. department of Mathematics, zhejiang university,{2., china) zhejiang Univ Inst Comp Graph & Image Proc Hangzhou 310027 Peoples R China zhejiang Univ Dept Math Hangzhou 310027 Peoples R China

The planar cubic hybrid hyperbolic polynomial curves and cubic H Bézier curves are presented. The conditions leading to inflection points and singularities (cusps and loops) are investigated and the shape of these curves is classified. The conclusions enable us to detect inflection points and singularities and get an idea of how to preserve the fair shape when designing such curves.

关键词： hybrid hyperbolic polynomial curve H-Bézier curve shape classification inflection points singularities

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Ordinal scheduling problem and its asymptotically optimal algorithms on parallel machine system

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science in china(Series F) 2004年第2期47卷 161-169页

作者： TAN Zhiyi1,2.& HE Yong1 1. department of Mathematics, zhejiang university,{2., china (email: tanzy@math.zju. *** heyong@math.zju.***) 2. State Key Laboratory of CAD & CG, zhejiang university,{2., china 1. department of Mathematics Zhejiang University 310027 Hangzhou China 2. State Key Laboratory of CAD & CG Zhejiang University 310027 Hangzhou China

Focusing on the ordinal scheduling problem on a parallel machine system, we discuss the background of ordinal scheduling and the motivation of ordinal algorithms. In addition, for the ordinal scheduling problem on identical parallel machines with the objective to maximize the minimum machine load, we then give two asymptotically optimal algorithm classes which have worst-case ratios very close to the upper bound of the problem for any given m. These results greatly improve the results proposed by He Yong and Tan Zhiyi in 2.02.

关键词： scheduling design and analysis of algorithm worst-case ratio.

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