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Some results on numerical divided difference formulas

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Science china Mathematics 2005年第11期48卷 1441-1450页

作者： Wang Xinghua,Wang Heyu & Ming-Jun Lai Department of Mathematics, zhejiang university, hangzhou 310028, china Computing center, zhejiang university, hangzhou 310012, china Department of Mathematics, university of Georgia, Athens, GA 30602-7403, USA 1. Department of Mathematics Zhejiang University 310028 Hangzhou China 2. Computing center Zhejiang University 310012 Hangzhou China 3. Department of Mathematics University of Georgia 30602-7403 Athens GA USA

The remainder estimates of numerical divided difference formula are given for the functions of lower and higher smoothness, respectively. Then several divided difference formulas with super-convergence are derived wit... 详细信息

关键词： numerical divided difference remainder estimate functions of lower smoothness sufficiently smooth functions super convergence.

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

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Rare Metals 2003年第4期22卷 298-303页

作者： ZHAO Xinbing, CAO Gaoshao, ZHANG Lijuan, and XIE JianDepartment of Materials Science and Engineering, zhejiang university, hangzhou 310027, china Department of Materials Science and Engineering Zhejiang University Hangzhou 310027

Some cobalt antimonides have been prepared and studied as the candidate anodematerials for lithium ion batteries. Reversible capacities of 424,423 and 546 mA.h.g^(-1) weremeasured at the first cycle for as-solidified CoSb_2, CoSb_3 and annealed CoSb_3 respectively. A lowlithium ions diffusion coefficient in the order of 10^(16) m^2.s^(-1) was estimated from thecoulometric titration measurements in the annealed CoSb_3 electrode. It was found that theelectrochemical properties of fine powders are significantly better than coarse powders. However theSEM picture shows that the nano-sized CoSb_3 powders gathered to larger granules, which worsenssomewhat the capacity retention of the nano-sized materials, although the volume capacities of theannealed and ball milled CoSb_3 remain near twice of that of graphite after 50 cycles.

关键词： Electrochemistry cobalt antimonides electrochemical analysis anodematerials lithium-ion batteries

A NEW METHOD TO PREPARE CHITOSAN MEMBRANE AS A BIOMEDICAL MATERIAL

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Chinese Journal of Polymer Science 2001年第5期19卷 467-470页

作者： Qiao-ling Hu Zheng-ping Fang Ying Zhao Cheng-wei Xu Institute of Polymer Composites zhejiang university hangzhou 310027, china zhejiang Univ Inst Polymer Composites Hangzhou 310027 Peoples R China

This paper reports a new method to prepare chitosan membrane which could be used as a biomedical material. Addition of a fixation agent composed of alcohol, glycerol and potassium hydroxide can accelerate the sol-gel transformation process and hence shorten the preparation period. The present method takes about 6 h to get a flexible membrane with fine appearance, The physical and biological properties of the membrane were also investigated and compared with the membrane prepared by conventional method.

关键词： chitosan membrane sol-gel transformation fixation agent

On Finite Rank Operators in CSL Algebras Ⅱ

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Acta Mathematica Sinica,English Series 1997年第3期13卷 321-326页

作者： Lu Shijie (Department of Mathematics,zhejiang university,hangzhou 310027,china)

For finite rank operators in a commutative subspace lattice algebra alg(?)we introduce the concept of correlation matrices,basing on which we prove that a finite rank operator in alg(?)can be written as a finite sum of rank-one operators in alg(?),if it has only finitely many different correlation *** we can recapture the results of ***,*** and *** as corollaries of our theorems.

关键词： CSL algebras Finite rank operators Correlation matrices

Ensemble learning HMM for motion recognition and retrieval by Isomap dimension reduction

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Journal of zhejiang university-Science A(Applied Physics & Engineering) 2006年第12期7卷 2063-2072页

作者： XIANG Jian, WENG Jian-guang, ZHUANG Yue-ting, WU Fei (School of Computer Science, zhejiang university, hangzhou 310027, china) School of Computer Science Zhejiang University Hangzhou China

Along with the development of motion capture technique, more and more 3D motion databases become available. In this paper, a novel approach is presented for motion recognition and retrieval based on ensemble HMM (hidden Markov model) learning. Due to the high dimensionality of motion’s features, Isomap nonlinear dimension reduction is used for training data of ensemble HMM learning. For handling new motion data, Isomap is generalized based on the estimation of underlying eigen- functions. Then each action class is learned with one HMM. Since ensemble learning can effectively enhance supervised learning, ensembles of weak HMM learners are built. Experiment results showed that the approaches are effective for motion data recog- nition and retrieval.

关键词： Feature Isomap HMM (hidden Markov model) Ensemble learning Motion recognition and retrieval

Micro-electrolysis technology for industrial wastewater treatment

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Journal of Environmental sciences 2003年第3期15卷 334-338页

作者： JIN Yi-zhong , ZHANG Yue-feng, LI Wei (Department of Environmental Engineering, zhejiang university, hangzhou 310027, china.) Department of Environmental Engineering Zhejiang University Hangzhou Chin

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of wastewater from pharmaceutical, dye-printing and papermaking plants. Results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis. For the use of micro-electrolysis in treatment of dye-printing wastewater, the removal rates of both chromaticity and COD were increased from neutral condition to acid condition for disperse blue wastewater; more than 90% of chromaticity and more than 50% of COD could be removed in neutral condition for vital red wastewater.

关键词： micro-electrolysis pharmaceutical wastewater dye-printing wastewater papermaking wastewater COD removal chromaticity removal

Strain tunability of dielectric and ferroelectric properties in epitaxial lead titanate thin films

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Theoretical & Applied Mechanics Letters 2011年第1期1卷 14-17页

作者： Jie Wang~(a)) School of Aeronautics & Astronautics,zhejiang university,hangzhou 310027,china School of Aeronautics & Astronautics Zhejiang University Hangzhou 310027 China

Many distinguished properties of epitaxial ferroelectric thin films can be tunable through the misfit *** strain tunability of ferroelectric and dielectric properties in epitaxial lead titanate ultrathin films is numerically investigated by using a phase field model,in which the surface effect of polarization is taken into *** response of polarization to the applied electric field in the thickness direction is examined with different misfit strains at room *** is found that a compressive misfit strain increases the coercive field and the remanent polarization while a tensile misfit strain decreases both of *** nonlinear dielectric constants of the thin films with tensile misfit strains are much larger than those of the thin films without misfit strains,which are attributed to the existence of the a/c/a/c multiple domains in the thin films under tensile misfit strains.

关键词： misfit strain ferroelectric thin film dielectric constant phase field model domain structures

Effect of background electrolytes on the adsorption of nitroaromatic compounds onto bentonite

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Journal of Environmental sciences 2009年第8期21卷 1044-1052页

作者： CHEN Baoliang, HUANG Wenhai Department of Environmental Science, zhejiang university, hangzhou 310028, zhejiang, china. [a]Department of Environmental Science Zhejiang University Hangzhou 310028 Zhejiang China

To further elucidate interaction of nitroaromatic compounds with mineral surface, the sorption of m-dinitrobenzene （m-DNB） and nitrobenzene to original bentonite in aqueous solution containing different electrolytes （i.e., KCl, NH4Cl, CaCl2 and Tetramethylammonium bromide （TMAB）） was studied. The sorption of m-DNB was greatly enhanced with the presence of KCl and NH4Cl, while little influence was observed with CaCl2 and TMAB, following the order of KCl 〉 NH4Cl 〉〉 TMAB, CaCl2, or DI water. For nitrobenzene, sorption enhancement only occurred at high nitrobenzene concentrations in the presence of KCl, and the solute equilibrium concentration at inflexion point was lowered with increasing KCl concentration. These sorption enhancements were significantly promoted with the increase of electrolyte concentration. The salting-out effect is insufficient to account for the sorption enhancement by original bentonite with increasing KCI or NH4Cl concentration. X-ray diffraction patterns of bentonite suspensions indicated that the sorption enhancement of m-DNB was attributed to the intercalation of K^＋ or NH4^＋ into bentonite interlayer and then dehydration with m-DNB to form inner-sphere complexes, which caused previously expanded bentonite interlayers to collapse in aqueous suspension, thus further enhanced the interaction of phenyl with siloxane surface. In comparison, the sorption enhancement of NB is attributed to the formation of outer-sphere complexes with K^＋ at high solute-loadings （〉 20（0-400 mg/kg）. The sorption of m-DNB to initially modified TMA^＋-bentonite and K^＋-bentonite was almost the same as respective sorption to original bentonite in solution containing TMA^＋ and K^＋.

关键词： sorption nitroaromatic compound bentonite cation type wastewater treatment

THE FLOW IN ROTATING CURVED CIRCULAR PIPE

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Journal of Hydrodynamics 2000年第1期12卷 108-116页

作者： Zhang Jin suo, Shen Xin rong, Zhang Ben zhao Department of Mechanics, zhejiang university, hangzhou 310027, P.R.china zhejiang Univ Hangzhou China

The combined effects of the system rotation (Coriolis force) and curvature (centrifugal force) on the flow in rotating curved circular pipe with small curvature are examined by perturbation method. A second order perturbation solution is presented. The secondary flow structure and the primary axial velocity distributions are studied in detail. The loops of the secondary flow are more complex than those in a curved pipe without rotation or a rotating straight pipe. Its numbers depend on the body force ratio F which represents the ratio of the Coriolis to the centrifugal force. The maximum of the axial velocity is pushed to either outer bend or inner bend, which is also determined by F. The results are confirmed by the results of other authors who studied the same problem by different methods.

关键词： secondary flow curved pipe perturbation method