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Unusual Behaviour of Dislocation Velocity Exponent in Dislocation Multiplication Model

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Journal of materials Science & Technology 1998年第3期14卷 215-218页

作者： Xaowei WANG(international Centre for materials {2., Institute of Metal Research, {3. Academy of sciences,shenyang 110015, china) international Centre for materials {2. Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The chaotic behaviour of dislocation multiplication process was investigated. The change of Lyapunov exponent which is used to determine the stability of quasi-periodic and chaotic behavior as well as that of equilibrium points, and periodic solution was reported by using an iteration model of dislocation multiplication. An unusual behavior of Lyapunov exponent and Feigenbaum exponent which respond to the geometric convergence of orbit from bifurcation to chaos was shown by dislocation velocity exponent m and there is a distinction on the tendency of convergence for the dislocation multiplication model when it was compared with logistic map. It is reasonable for the difference to be analyzed from the materials viewpoint. (Edited author abstract) 9 Refs.

关键词： Unusual Behaviour of Dislocation Velocity Exponent in Dislocation Multiplication Model

Multirange Fractals in materials: Applications to Fracture and Mechanical Alloying under Ball Milling

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Journal of materials Science & Technology 1997年第4期13卷 255-259页

作者： Chiwei LUNG(international Centre for materials {2., Institute of Metal Research,{3. Academy of sciences, shenyang 110015, china) international Centre for materials {2. Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

A new model of multirange fractals is proposed to explain the experimental results observed on the fractal dimensions of the fractured surfaces in materials. A new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It shows the importance of fractorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals. Mechanical alloying process under ball milling as a non-equilibrium dynamical system has been also analyzed.

关键词： Ball Applications to Fracture and Mechanical Alloying under Ball Milling Multirange Fractals in materials

Statistical theory for hydrogen bonding fluid system of A_aD_d type (I): The geometrical phase transition

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Science china Chemistry 2006年第6期49卷 499-506页

作者： WANG Haijun1,2. HONG Xiaozhong3. GU Fang1 & BA Xinwu1 1. College of Chemistry and Environment Science, Hebei University, Baoding 071002. china 2. international Center for {2. physics, chinese Academy of sciences, shenyang 110016, china 3. College of physics Science and Technology, Hebei University, Baoding 071002. china College of Chemistry and Environment Science Hebei University Baoding China international Center for materials {2. Chinese Academy of Sciences Shenyang China College of physics Science and Technology Hebei University Baoding China

The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.

关键词： hydrogen bonding fluid, equilibrium free energy, geometrical phase transition.

Universality and Specificity of Fractal Dimension of Fractured Surfaces in materials

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Journal of materials Science & Technology 2000年第1期16卷 1-4页

作者： Chiwei LUNG and Shenggang WANG (international Centre for materials {2., Institute of Metal Research, {3. Academy of sciences, shenyang 110015, china) international Centre for materials {2. Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

After calculation on the fracture angles under various conditions of specific surface energies with different symmetry operations of rotation, the complicated behavior of dependence of fractal dimension on the structure of crystal is shown. It is found that the crack propagates along the weakest crystal plane no matter what the direction of the maximum stress is if the anisotropy is sufficiently strong; and then, the fractal dimension of the fractured surfaces might be determined by the approximate fractal structure already existed in the material. Specificity of the fractal dimension of fractured surfaces would be easy to appear in this case. Reversely, the crack propagates along the direction of the maximum stress no matter what direction of the weakest crystal plane is if the anisotropy is sufficiently weak. Universality of the fractal dimension of fractured surfaces would be possible to appear in this case. In many real materials, universality and specificity of the materials are associated. The fractal dimension measured may more or less be influenced by the structure of materials and it shows its universality through the specificity of materials.

关键词： Universality and Specificity of Fractal Dimension of Fractured Surfaces in materials

Effects of Positron Diffusion and Its Application in Composite System

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Journal of materials Science & Technology 2000年第3期16卷 311-314页

作者： Jian JIANG, Xinzhang ZHOU and ChiWei LUNG (international Center for materials {2., Institute of Metal Research, {3. Academy of sciences, shenyang 110015, china) international Center for materials {2. Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The effects of positron diffusion on the measured S parameter have been investigated by a point-source diffusion model and a δ function method. Firstly, the theoretical analyses of the effects are presented for the samples of a homogeneous semi-infinite medium and a film of definite thickness. Then the results are used to analyze the S parameters in several composite systems and interface models.

关键词： Effects of Positron Diffusion and Its Application in Composite System

Investigation of changes in properties of water under the action of a magnetic field

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Science china(physics,Mechanics & Astronomy) 2008年第11期51卷 1621-1632页

作者： PANG XiaoFeng1,2.& DENG Bo1 1 Institute of Life Science and Technology, University of Electronic Science and Technology of china, Chengdu 610054, china 2.{2. Centre for materials physics, chinese Academy of sciences, shenyang 110015, china Institute of Life Science and Technology University of Electronic Science and Technology of China Chengdu China international Centre for materials {2. Chinese Academy of Sciences Shenyang China

The properties of water and their changes under the action of a magnetic field were gathered by the spectrum techniques of infrared, Raman, visible, ultraviolet and X-ray lights, which may give an insight into molecular and atomic structures of water. It was found that some properties of water were changed, and a lot of new and strange phenomena were discovered after magnetization. Magnetized water really has magnetism, which has been verified by a peak shift of X-ray diffraction of magnetized water + Fe3.4 hybrid relative to that of pure water + Fe3.4 hybrid, that is a saturation and memory effect. The properties of infrared and ultraviolet absorptions, Raman scattering and X-ray diffraction of magnetized water were greatly changed relative to those of pure water; their strengths of peaks were all increased, the frequencies of some peaks did also shift, and some new peaks, for example, at 5198, 8050 and 93.0 cm?1, occurred at 2.°C after water was magnetized. In the meanwhile, the magnetized effects of water are related to the magnetized time, the intensity of an externally applied magnetic field, and the temperature of water, but they are not a linear relationship. The study also showed a lot of new and unusual properties of magnetized water, for example, the six peaks in 3.00–3.00 cm?1 in infrared absorption, the exponential increase of ultraviolet absorption of wave with the decreasing wavelength of light of 2.0–3.0 nm, the frequency-shifts of peaks, a strange irreversible effect in the increasing and decreasing processes, as well as a stronger peak of absorption occurring at 50°C, 70°C and 80°C, the existence of many models of motion from 85°C to 95°C in 8000–10000 cm?1, and so on. These results show that the molecular structure of water is very complicated, which needs further study. Furthermore, the macroscopic feature of mechanics, for instance, surface tension force of magnetized water, was also measured. Experiments discovered that the size in contact angle

关键词： pure water magnetized water magnetic-field physical property spectrum saturation and memory effect mechanical feature surface tension force polarization angles of contact

High-pressure synthesis and properties of CeO_2.ZrO_2.solid solution

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chinese Science Bulletin 2001年第10期46卷 801-806页

作者： XU Dapeng, WANG Quanyong, LU Zhe, LIU Zhiguo, ZHANG Gongmu & SU Wenhui1. Department of physics, Jilin University, Changchun 13.02. china 2. {2. Center for materials physics, chinese Academy of sciences, shenyang 110015, china 3. Center for Condensed Matter and Radiation physics, china Center of Advanced Science and Technology (World Laboratory), Beijing 100080, china Department of physics Jilin University Changchun China international Center for materials {2. Chinese Academy of Sciences Shenyang China Center for Condensed Matter and Radiation physics China Center of Advanced Science and Technology (World Laboratory) Beijing China

Using nanoparticles of CeO2.and ZrO2.prepared by the chemical precipitation method as starting materials, the single-phase cubic Ce0.5Zr0.5O2.solid solution (c-Ce0.5Z0.5O2. has been synthesized under 3.1 GPa at 1073.K for the first time. The structure of the c-Ce0.5Zr0.5O2.has not been changed before and after annealing at 773.K for 1 h. Only an unknown EPR signal (g =1.990) has been observed in the c-Ce0.5Zr0.5O2.and not varied after annealing at 773.K for 1 h, which exhibited that there exists no Ce3. in the c-Ce0.5Zr0.5O2.and the Ce4+ has not been reduced into Ce3. after annealing. The transport mechanism is ionic for the c-Ce0.5Zr0.5O2. The bulk conductivity (a =1.2.10-5 S/cm at 82. K, σ=2.1 ×10-3.S/cm at 112. K) is the same as that of CeO2. but smaller than that of Y2.3.stabilized ZrO2. A marked curvature at T = 82. K has been observed in the Arrhenius plot of the bulk conductivity. The activation energy below 82. K is lower than that above 82. K, and the reason has been discussed.

关键词： CeO2.ZrO2 nanocrystalline high-pressure and -temperature solid-state reaction solid solution.

Energy Spectrum of YAG:Cr3. and Thermal Shifts of Its R Lines

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Communications in Theoretical physics 2005年第7期44卷 165-170页

作者： MA Dong--Ping CHEN Ju--Rong Department of Applied physics, Sichuan University, Chengdu 610065, china {2. Centre for {3. physics, the chinese Academy of sciences, shenyang 110015, china Department of Applied physics Sichuan University Chengdu 610065 China international Centre for materials {2. the Chinese Academy of Sciences Shenyang 110015 China

Traditional ligand-field theory has to be improved bv taking into account both "pure electronic" contributionand electron-phonon interaction one （including lattice-vitbrational relaxation energv）. By means of improved ligand-fieldtheory, R1, R2. R3., R2., and R1′ lines, U band, ground-state zero-field-splitting （GSZFS） and ground-state g factors aswell as thermal shifts of R1line and R2.ine of YAG:Cr3.have been calculated. The results are in very good agreementwith the experimental data. In contrast with ruby, the octahedron of ligand oxygen ions surrounding the central Cr3.ion in YAG:Cr3.is compressed along the [111] direction. Thus, for YAG:Cr3.and ruby, the splitting of t2. 4A2.or t2. 2.)has opposite order, and the trigonal-field parameters of the two crystals have opposite signs. In thermal shifts of R1andR2.ines of YAG:Cr3., the tetnperature-dependent contributions due to EPI are dominant.

关键词： improved ligand-field theory electron-phonon interaction Stokes shift energy spectrum thermal shift g factor

Properties of nonadiabatic quantum fluctuations of the strongly coupled electron-phonon systems

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 258-268页

作者： PANG XiaoFeng Institute of Life Science and Technology,University of Electronic Science and Technology of china,Chengdu 610054,china {2. Centre for {3. physics,chinese Academy of sciences,shenyang 110015,china Institute of Life Science and Technology University of Electronic Science and Technology of China Chengdu China international Centre for materials {2. Chinese Academy of Sciences Shenyang China

A new variational-ansatz of states of electrons and phonons was proposed on the basis of the Holstein model in strongly coupled electron-phonon systems for studying the influence of nonadiabatic phonon fluctuation,arising from the motion and density fluctuation of electrons,on the properties of ground state,uncertainty relation,stability of polarons,charge density wave (CDW) and phonon staggered ordering. The new ansatz represents the correlation among the displacement and squeezing states of phonons and polaron’s state of electrons as well as the squeezing-antisqueezing effect. The correlation and squeezing-antisqueezing ef-fect result in the decrease of ground state energy,enhancement of stability of the systems,increase of binding energy of the polarons,weakening of the growing speed of polaron narrowing of the electron band,increase of the charge density wave order and suppression of the increased tendency of anomalous quantum fluctuation of the phonons in such a case,when compared with the uncorrelated case in the systems. The results obtained show that the ground state determined by the new state ansatz is most stable,thus the new ansatz describing the properties of the coupled electron phonon systems is very relevant and available,especially in strongly coupled and largely squeezed cases.

关键词： squeezing-antisqueezing effect state-ansatz polaron coupled electron-phonon systems quantum fluctuation