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Biomimetic Study on Helical Fiber Composites

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Journal of Materials Science & Technology 1998年第1期14卷 29-32页

作者： Zhang, K Wang, YQ zhou, bl Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China Acad Sinica Int Ctr Mat Phys Shenyang 110015 Peoples R China

The innovative approach imparting strength and toughness to carbon fiber reinforced polymer composites (CFRP) is put forward from the viewpoint of biomimetics. Helical fibers produced by twisting fiber bundle are arranged in the matrix to simulate the unique structure of natural fibers. The results on the CFRP with helical fiber bundles show that, under the same state of strong fiber/matrix interface, the impact fracture toughness can be improved substantially compared to conventional composites with plain fibers. The beneficial effect is attributed to the helical fiber bundles which act as single fibers of huge diameter effectively increasing the fiber elastic energy.

关键词： Carbon fiber reinforced plastics

Solitary Multiphonon Bound States and Periodic Wave Solutionin Inharmonic Molecular Crystals

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Journal of Materials Science & Technology 1996年第3期12卷 161-165页

作者： Liu, WM Pu, FC zhou, bl ACAD SINICA INST MET RESINT CTR MAT PHYSSHENYANG 110015PEOPLES R CHINA

Employing the coherent state ansatz and the time-dependent variational principle, we obtain a partial differential equation of motion from Hamiltonian in inharmonic molecular crystals. By using the method of multiple scales, we reduce this equation into the envelope function and find that the amplitude function satisfied a nonlinear Schrodinger equation. Introducing the inverse scattering transformation, we gain the single-, two- and N- soliton solutions. The energy and the spatial configurations of the system are given. We also acquire the periodic wave solution and analyze its stability.

关键词： Wave Solitary Multiphonon Bound States and Periodic Wave Solutionin Inharmonic Molecular Crystals Rev

Conductance Behaviour of Tunneling Junctions with Fractal Structures

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Journal of Materials Science & Technology 1998年第5期14卷 385-389页

作者： Qin, RS Su, SX Guo, JD He, GH zhou, bl Acad Sinica Inst Met Res Int Ctr Mat Phys Shenyang 110015 Peoples R China

Conductance behaviours of resonant tunneling junction with elementary, second and third Sierpinskii structures are considered. Numerical calculation shows that a tunneling junction with higher order fractal structure possesses more meticulous resonant behaviour. it provides the possibility of fabricating exact energy selecting tunneling devices. The structure of tunneling junction can be determined by experimental observation. The energetic spectrum of such device is supposed to be a fractal one. The effect of electrode is alteration of the shape and maximum of conductance peaks.

关键词： Conductance Behaviour of Tunneling Junctions with Fractal Structures Rev

A Model for Liquid-Diffusion Catalytically Grown Fibrous Carbon Material

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Journal of Materials Science & Technology 1999年第1期15卷 1-4页

作者： Zhang, WG Cheng, HM Su, G Fan, YY Li, F Shen, ZH zhou, bl Chinese Acad Sci Met Res Inst Shenyang 110015 Peoples R China

A mechanism for the catalytically growth of vapor grown fibrous carbon (VGFC) preparing from the floating catalyst method has been proposed, in which liquid diffusion-determined diffusion of carbon atoms through catalyst particles is described mathematically, and the physical and chemical properties of the catalyst particles during the growth process are taken into account. From the model the growth rate and grown length of VGFC are calculated theoretically which coincides with the experimental data; and the necessity of reducing gas such as hydrogen in preparing VGFC is explained as to reduce Fe3C, which acts as intermediate catalyst shown by the model. Fe3C formed on the surface of gamma-Fe will stop the growth of carbon fiber if they can not be reduced at once. Additionally, the growth temperature and diameter of VGFC are also discussed in the paper.

关键词： Li Cs A Model for Liquid-Diffusion Catalytically Grown Fibrous Carbon Material

PREPARATION OF POLYURETHANE EMULSION

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Chinese Chemical Letters 1995年第7期6卷 625-626页

作者： zhou, QY Song, MD Zhang, BH He, bl Nankai Univ Inst Polymer Chem Tianjin 300071 Peoples R China

A technique has been developed for preparing stable polyurethane emulsion which provides thermosetting film without the use of emulsifying agents. The reaction of an isocyanate terminated prepolymer with a stoichiometric excess of diethylenetriamine in the presence of ketones yields the polyurethane-amine). Then the free amino group is generated when the polymer is treated with epichlorohydrin and the reaction occurs between them, and a stable self-emulsifiable thermosetting urethane emulsion can be obtained. This paper also presents the effect of the curing temperature and time on the typical mechanical properties of the films from this urethane emulsion.

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Calixthiacrown:A New Multidentate Ligand for Platinum Metal

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Chinese Chemical Letters 1997年第3期8卷 213-214页

作者： Chen, YY Zhong, ZL zhou, YS Zhang, bl Lu, XR WUHAN UNIV DEPT CHEMWUHAN 430072PEOPLES R CHINA

5, 11, 17, 23-Tetra-tertbutyl-25,27-dihydroxy-26, 28-1', 7',13'-trioxa-4', 10'-dithiatridecene calix [4]arene (Calix [4]dithiacrown-5) was synthesized from tetra-tertbutyl-calix[4]arene via 1,3-lower rim functionallization with chloroethyltosylate, followed by ring-closing condensation with beta,beta'-dimercaptoethyl ether in the presence of sodium ethoxide as a base under nitrogen atmosphere. It was found that the calix[4]dithiacrown-5 can form a platinum complex and the complex can catalyze the hydrosilylation of olefins with triethoxysilane efficiently.

关键词： Cl FAB Calixthiacrown ppm

CONVERGENCE OF A CONSERVATIVE DIFFERENCE SCHEME FOR THE ZAKHAROV EQUATIONS IN TWO DIMENSIONS

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Journal of Computational Mathematics 1997年第3期15卷 219-232页

作者： Guo, bl Chang, QS INST APPL PHYS & COMPUTAT MATH BEIJING 100088PEOPLES R CHINA CHINESE ACAD SCI INST APPL MATHBEIJINGPEOPLES R CHINA

A conservative difference scheme is presented for the initial-boundary-value problem of a generalized Zakharov equations. On the basis of a prior estimates in L-2 norm, the convergence of the difference solution is proved in order O(h(2) + r(2)). In the proof, a new skill is used to deal with the term of difference quotient (e(j,k)(n))t. This is necessary, since there is no estimate of E(x, y, t) in L-infinity norm.

关键词： Math CONVERGENCE OF A CONSERVATIVE DIFFERENCE SCHEME FOR THE ZAKHAROV EQUATIONS IN TWO DIMENSIONS

THE GLOBAL DUFORT-FRANKEL DIFFERENCE APPROXIMATION FOR NONLINEAR REACTION-DIFFUSION EQUATIONS

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Journal of Computational Mathematics 1998年第3期16卷 275-288页

作者： Lu, BN Wan, GH Guo, bl Xiangtan Univ Inst Computat & Appl Math Xiangtan 411105 Peoples R China Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China Shaanzi Normal Univ Dept Math Xian 710062 Peoples R China Inst Appl Phys & Computat Math Ctr Nonlinear Studies Beijing 100088 Peoples R China

In this paper, the initial value problem of nonlinear reaction-diffusion equation is considered. The Dufort-Frankel finite difference approximation for the long time scheme is given for the d-dimensional reaction-diffusion equation with the two different cases. The global solution and global attractor are discussed for the Dufort-Frankel scheme. Moreover properties of the solution are studied. The error estimate is presented in a finite time region and in the global time region for some special cases. Finally the numerical results for the equation are investigated for Allen-Cahn equation and some other equations and the homoclinic orbit is simulated numerically.

关键词： global Dufort-Frankel method reaction-diffusion equation global attractor error estimate numerical experiments

STM image of tungstosilicic acid molecular layer on highly oriented pyrolytic graphite

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Chinese Journal of Chemistry 1995年第6期13卷 493-496页

作者： Zhang, bl Wang, EK CHINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022JILINPEOPLES R CHINA

Molecular layer of tungstosilicic acid (H4SiW12O40) deposited on freshly-cleaved highly oriented pyrolytic graphite (HOPG) was observed by scanning tunneling microscopy (STM) in air at room temperature. The molecular dimension (11.5 Angstrom) of H4SiW12O40 measured by STM is consistent with known crystallographic parameter. We also imaged the boundary of H4SiW12O40 molecular layer on HOPG showing that molecular layer of H4SiW12O40 was formed. It has been proved that individual tungstosilicic acid species is imaged. The probable reason for the formation of the molecular layer is also discussed.

关键词： tungstosilicic acid HOPG STM