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Classification and Approximate Solutions to a Class of Perturbed Nonlinear Wave Equations

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Communications in Theoretical Physics 2009年第11期52卷 769-772页

作者： zhang zhi-yong CHEN Yu-Fu yong Xue-Lin School of Mathematical Sciences Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Mathematics and Physics North China Electric Power University Beijing 102206 China

A complete approximate symmetry classification of a class of perturbed nonlinear wave equations isperformed using the method originated from Fushchich and ***,large classes of approximate invariantsolutions of the equ... 详细信息

关键词： approximate symmetry Lie reduction approximate solution

Conservation Laws of a Class of Combined Equations

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Communications in Theoretical Physics 2009年第1期51卷 35-38页

作者： zhang zhi-yong yong Xue-Lin CHEN Yu-Fu School of Mathematical Sciences Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Mathematics and Physics North China Electronic Power University Beijing 102206 China

In this paper, we investigate conservation laws of a class of partial differential equations, which combines the nonlinear telegraph equations and the nonlinear diffusion-convection equations. Moreover, some special conservation laws of the combined equations are obtained by means of symmetry classifications of wave equations uxx = H （x）utt.

关键词： symmetry conservation law multiplier differential characteristic set

Dual Space Analyzing Based on Symmetry Properties for Phonons of Si Quantum Dot

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Communications in Theoretical Physics 2002年第7期38卷 91-98页

作者： QIN Guo-Yi REN Shang-Fen zhang zhi-yong Department of Physics Nanjing University Nanjing 210093 China Department of Physics Illinois State University Normal IL 61790-4560 USA Department of Physics Tianjin Normal University Tianjin 300074 China

Phonon modes in spherical Si quantum dots (QDs) with up to 7.9 nm in diameter are calculated by using the projection operators of the group theory into valence force field model. The phonons of dot modes in each of five irreducible representations (symmetries) are classified by using a dual space analysis method. It is found that the bulk-like modes with localization radius much smaller than the dot's radius have clearly pronounced bulk specific-κdefinite bulk band (one in six modes). In Si dots of all sizes, each specific bulk-like dot mode has specific *** dot modes and bulk-like X-derived TA and LA dot modes red-shift in frequency with decreasing dot size. There is almost not LO/TO mixing for bulk-like modes. As for the surface-like modes localized at the periphery of the dot,their eigenmodes have not a dominant bulk specific-κ point parentage or a dominant BZ parentage around some special point. They are a superposition of many bulk bands with κ from all over the bulk BZ. They have much significant mode mixing than the bulk-like phonons. The classification of dot modes based on the symmetry of group theory will bring advantageous to the discussion of Ramam spectrum, electron-phonon interaction and other phonon-assisted effects in QDs.

关键词： phonon modes, quantum dots, dual space analyzing

Cystamine ameliorates liver fibrosis induced by carbon tetrachloride via inhibition of tissue transglutaminase

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World Journal of Gastroenterology 2007年第32期13卷 4328-4332页

作者： Jiang-Feng Qiu zhi-Qi zhang Wei Chen zhi-yong Wu Department of General Surgery Renji Hospital Shanghai Jiaotong University School of Medicine Shanghai 200127 China

AIM： To investigate the anti-fibrosis effect of the tissue transglutarninase （tTG） specific inhibitor cystarnine on liver fibrosis. METHODS： Sixty-eight male Sprague Dawley rats were divided into three groups： normal control, liver fibrosis control and cystamine-treated group. Liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride （CCl4）, and Cystarnine was administrated by intraperitoneal injection starting 2 d before the first administration of CCl4. Animals in each group were further divided into 2 subgroups according to two time points of 4 wk and 8 wk after treatment. Hepatic function, pathological evaluation （semi-quantitative scoring system, SSS） and liver hydroxyproline （Hyp） content were examined. Real-time PCR was used to detect the expression of tTG, smooth muscle alpha actin （α-SMA）, tissue inhibitor of metalloproteinase 1 （TIMP-1） and collagen-1 mRNA. The expressions of tTG and α-SMA protein were detected by Western Blotting. RESULTS： Eight weeks after treatment, the SSS score of liver was significantly less in the cystamine group than that in the fibrosis control group （P 〈 0.01）. The levels of alanine arninotransferase （ALT） and total bile acid （TBA） at the 4 wk and 8 wk time points were decreased in the cystamine group compared with those in fibrosis controls （P 〈 0.01）. Liver hydroxyproline content at the 4 wk and 8 wk time points showed a substantial reduction in the cystamine group compared to fibrosis controls （P 〈 0.01）. The expression of tTG, α-SMA, collagen-1, TIMP-1 mRNA and tTG, as well as α-SMA protein was downregulated in the cystamine group compared to fibrosis controls. CONCLUSION： Cystamine can ameliorate CCl4 induced liver fibrosis and protect hepatic function. The possible mechanism is related to the reduced synthesis of the extracellular matrix （ECM） caused by the inhibition of hepatic stellate cell activation and decreased expression of TIMP-1.

关键词： Tissue transglutaminase Cystamine Liver fibrosis Cross linking Extracellular matrix

Relationship between chloride diffusivity and pore structure of hardened cement paste

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第5期12卷 360-367页

作者： Guo-wen SUN Wei SUN Yun-sheng zhang zhi-yong LIU Jiangsu Key Laboratory of Construction Materials.Southeast University Nanjing 211189china

Based on effective media theory, a predictive model, relating chloride diffusivity to the capillary pores, gel pores, tortuosity factor, and pore size distribution of hardened cement, is proposed. To verify the proposed model, the diffusion coefficient of chloride ions, the degree of hydration, and peak radius of capillary pores of cement paste specimens were measured. The predicted results for chloride diffusivity were compared with published data. The results showed that the predicted chloride diffusivity of hardened cement paste was in good agreement with the experimental results. The effect of the evolution of pore structures in cement paste on chloride diffusivity could be deduced simultaneously using the proposed model.

关键词： Hardened cement paste Chloride diffusivity Porosity Tortuosity factor Constrictivity Key words: Hardened cement paste, Chloride diffusivity, Porosity, Tortuosity factor, Conslrictivity

Theoretical Investigation for Unexpected Transition Metal-π Interaction Enhanced Fluorescence in Cu-π-diborene

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Chinese Journal of Structural Chemistry 2020年第6期39卷 1126-1134页

作者： zhang zhi-yong zhang Zhong-zhi LUO Yi-Jing zhang Guang-Qing Laboratory of Heavy Oil Processing College of Chemical Engineering and EnvironmentChina University of PetroleumBeijing 102249China School of Mechanical Materials&Mechatronic EngineeringUniversity of WollongongWollongong NSW2S22Australia

Unexpected transition metal(TM)-π interaction enhanced fluorescence in Cu-π-diborene complexes is a novel phenomenon compared with other metal enhanced fluorescence. In order to discover the mechanism, theoretical investigation was carried out for Cu-π-diborene as well as diborene. Simulation results show the main decay method in diborene and Cu-π-diborene are internal conversion(IC) and fluorescence(FL), respectively. TM-π interaction leads to larger HOMO-LUMO gap of Cu-π-diborene than that of the free diborene, which results in lower IC rates and makes them smaller than the FL rates. At the same time, ISC rates are always smaller than IC and FL rates, which cause enhanced fluorescence of Cu-π-diborene. More interestingly, even though Cu-π-diborene shows enhanced fluorescence, intersystem crossing(ISC) in Cu-π-diborene is enhanced from diborene. The theoretical analysis shows the competition among IC, FL and ISC is the key factor for TM-π interactions enhanced fluorescence, which also shows that cation-π complexes have potential to be used as luminescent probes.

关键词： boron-boron double bond transition metal-interaction fluorescence quantum yield

Direct Observation of Domain-Inverted Regions in Proton-Exchanged LiNbO_(3) Using Transmission Electron Microscopy

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Chinese Physics Letters 1996年第5期13卷 362-365页

作者： zhang zhi-yong WANG Lu-chun ZHU yong-yuan ZHU Shi-ning MIN Nai-ben National Laboratory of solid state microstructures Nanjing Universityand Center for Advanced Studies in Science and Technology of MicrostructuresNanjing 210093

Direct observation of the domain-in-verted regions in LiNbO_(3) formed by proton exchange followed by heat treatment is performed by using transmission electron microscopy.A charged straight 180°tivinning domain boundary was revealed and compared with winding domain boundaries in LiNbO_(3) grown by Czochralski *** results are significant to studying the mechanism of domain inversion and morphology of inversion domains.

关键词： method. straight Electron

First-Principles Study of Fe-Doped ZnO Nanowires

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Chinese Physics Letters 2011年第12期28卷 207-210页

作者： zhang Fu-Chun zhang Wei-Hu DONG Jun-Tang zhang zhi-yong College of Physics and Electronic Information Yan'an UniversityYan'an 716000 Information Science and Technology Institution Northwest UniversityXi'an 710127

Using first-principles theory,we predict magnetic,electronic and optical properties in Fe-doped ZnO *** results show that ferromagnetic(FM)coupling of configuration V is the most stable,and the strong hybridization effect between Fe 3d and O 2p states is found near the Fermi level,and it is obvious that the ferromagnetic system is electron−spin polarization of 100%and *** antiferromagnetic(AFM)coupling,the system generates small spin polarization near the Fermi level,indicating *** magnetic moments mainly arise from Fe 3d *** addition,the results of optical properties show that the Fe-doped ZnO nanowires have apparent absorption peaks in the ultraviolet band and that there is a small red shift and a strong blue shift in the near and far ultraviolet band,indicating that Fe-doped ZnO nanowires are a type of magneto-optical materials with great promise.

关键词： nanowires ultraviolet coupling

Signal Blind Recovery in Communication Systems Using Support Vector Machines

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南京邮电大学学报（自然科学版） 2010年第1期30卷 1-5页

作者： RUAN Xiu-kai zhang zhi-yong College of Telecommunications ＆ Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China College of Automation Nanjing University of Posts and Telecommunications Nanjing 210046 China

This paper focuses on the applications of the support vector machines in solving the problem of blind recovery in digital communication *** introduce the technique of support vector machines briefly,the development of blind equalization and analyze the problems which need to be resolved of the blind *** the applicability of support vector machines in blind problem is highlighted and ***,merit and shortage of blind equalization using support vector machines which is already exist to be discussed and the direction of further research is indicated.

关键词：通信信号处理系统编码 BPSK