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Fractal Nature of Crack Growth under Different Temperature

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Journal of Materials Science & technology 1996年第2期12卷 143-148页

作者： Qunsheng CAO (Dept. of physics, wuhan Yejin university of Science & {3., wuhan 43.081, china) Dept. of physics Wuhan Yejin University of Science and Technology Wuhan 430081 China

We have studied numerically a simple crack growth model in a two-dimensional triangular lattice of bonds and nodes which incorporates the surface of a growing crack bond-breaking probability P-i similar to exp{(-V-i+E(i))phi(T)}, where E(i) is elastic energy stored in the i-th bond. Different energy temperature factors phi(T) are employed during crack formation and propagation process with a uniform dilation strain case and a shear case and with periodic boundary condition in the horizontal direction. Our results show that the patterns of the cracks generated are fractal structure and the effective fractal dimensionalities decrease with the increase of the temperature factor phi(T)(the absolute temperature T decreasing). In the paper we also discuss the relation between the effective fractal dimension D-eff (the radius R(g) of gyration) and the fractal dimensions D (the radius R of circular), and also give their modification values Omega about two kinds of methods in the lattice model.

关键词： Nature Fractal Nature of Crack Growth under Different Temperature

A Multi-Soliton Solution of the DNLS Equation Based on Pure Marchenko Formalism

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wuhan university Journal of Natural Sciences 2010年第1期15卷 36-42页

作者： ZHOU Guoquan School of physics and technology,wuhan {3.,wuhan 430072.Hubei,china School of physics and technology Wuhan University Wuhan China

By means of some algebraic techniques,especially the Binet-Cauchy formula,an explicit multi-soliton solution of the derivative nonlinear Schrdinger equation with vanishing boundary condition is attained based on a pure Marchenko formalism without needing the usual scattering data except for given N simple poles. The one-and two-soliton solutions are given as two special examples in illustration of the general formula of multi-soliton solution. Their effectiveness and equivalence to other approaches are also demonstrated. Meanwhile,the asymptotic behavior of the multi-soliton solution is discussed in detail. It is shown that the N-soliton solution can be viewed as a summation of N one-soliton solutions with a definite displacement and phase shift of each soliton in the whole process(from t →∞ to t → +∞ ) of the elastic collisions.

关键词： soliton derivative nonlinear Schrdinger (DNLS) equation nonlinear equation Marchenko equation

Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3._(12) thin films prepared by sol-gel method

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Science china(Technological Sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2 & GUO DongYun3.1 School of Materials Science and technology, wuhan university of technology, {3. 43.070, china 2 School of Mechanical Engineering, Chongqing university of Science and technology, Chongqing 400050, china 3.Department of physics, wuhan university, wuhan 430072. china School of Materials Science and technology Wuhan University of Technology School of Mechanical Engineering Chongqing University of Science and Technology

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3.12, BHT) thin films on Pt/Ti/SiO2/Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2Pr and 2Ec of the 600-nm-thick BHT film were 3..4 μC/cm2 and 3.6.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 3.0 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93. of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3.12 thin film sol-gel method ferroelectric property fatigue dielectric constant

Weak martingale Hardy spaces and weak atomic decompositions

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Science china Mathematics 2006年第7期49卷 912-921页

作者： HOU Youliang & REN Yanbo School of Mathematics and Statistics, wuhan university, wuhan 430072. china Department of Mathematics & physics, Henan {3. of Science and technology, Luoyang 471003. china School of Mathematics and Statistics Wuhan University Wuhan China Department of Mathematics & physics Henan University of Science and Technology Luoyang China

In this paper we define some weak martingale Hardy spaces and three kinds of weak atoms. They are the counterparts of martingale Hardy spaces and atoms in the classical martingale Hp-theory. And then three atomic decomposition theorems for martingales in weak martingale Hardy spaces are proved. With the help of the weak atomic decompositions of martingale, a sufficient condition for a sublinear operator defined on the weak martingale Hardy spaces to be bounded is given. Using the sufficient condition, we obtain a series of martingale inequalities with respect to the weak Lp-norm, the inequalities of weak (p ,p)-type and some continuous imbedding relationships between various weak martingale Hardy spaces. These inequalities are the weak versions of the basic inequalities in the classical martingale Hp-theory.

关键词： martingale, weak Hardy space, weak atom, atomic decomposition.

Nonlinear Refractive Index and Absorption Coefficient of Single-Shell Semiconductor Carbon Nanotube

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wuhan university Journal of Natural Sciences 2003年第3A期8卷 833-836页

作者： Lu Ni,Xiong Gui\|guang  School of physics and technology, wuhan university, {3. 430072. Hubei, china School of physics and technology Wuhan University Wuhan Hubei China

The nonlinear refractive index and absorption coefficient of single\|shell semiconductor carbon nanotubes(CN s ) are calculated based on the two\|band approximation and Genkin\|Mednis approach. The results of nonlinear refractive index and absorption coefficient reach the order of 10 -8 and 10 -4 cm 2\5W -1 separately, which indicates that CN s have wonderful nonlinear optical properties. Taking into account the temperature effect and overlapping of σ and π orbits, the effect of relaxation term and chiral angle is discussed. The results show that the smaller the relaxation term, the larger the nonlinear absorption coefficient and refractive index. At the same time, CN s with different chiral angles have different results due to their different energy gap.

关键词： nonlinear refractive index nonlinear absorption coefficient relaxation chiral angle

Electron microscopy study of the sakhaite from endogenous borate deposit in Hunan, china

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Science china Earth Sciences 2004年第3期47卷 232-238页

作者： LIU Xiangwen1,2, YANG Guangming2, ZOU Huamin3. QU Jing1 & ZHAO Wenxia4 1. Graduate School, china university of Geosciences, wuhan 43.074, china 2. Test Center, china university of Geosciences, wuhan 43.074, china 3. physics and technology college, wuhan university, wuhan 430072. china 4. Test Center, Zhongshan university, Guangzhou 510275, china Graduate School China University of Geosciences Wuhan 430074 China Test Center China University of Geosciences Wuhan 430074 China physics and technology college Wuhan University Wuhan 430072 China Test Center Zhongshan University Guangzhou 510275 China

Sakhaite specimens from an endogenous borate deposit in Hunan Province, china have been studied in detail by means of transmission electron microscopy (TEM). The selected area electron diffraction (SAED) patterns obtained with different crystal zone axes show that the crystal system is cubic, with a = 1.463.nm. The convergent beam electron diffraction (CBED) patterns indicate that the point group and space group of sakhaite is m3. and Fd3., respec-tively. The space group of synthetic sakhaite determined by Chichagov (1974) is F413.. The possible reasons why the space groups of the natural and the synthetic sakhaites are different are discussed.

关键词： sakhaite, space group, convergent beam electron diffraction (CBED).

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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Science china(Technological Sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3. WANG Guilan1 & ZHENG Qiguang2 1. School of Material Science and technology, Huazhong university of Science and technology, {3. 43.074, china 2. Institute of Laser technology and Engineering, Huazhong university of Science and technology, {3. 43.074, china 3. Mechanical Engineering college, Hubei university of technology, {3. 43.068, china School of Material Science and technology Huazhong University of Science and Technology

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

The Ground and Excitation Levels of the Trimer

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wuhan university Journal of Natural Sciences 1998年第2期3卷 163-164页

作者： You Pu(Department of physics, wuhan university, wuhan {3.china) wuhan university Department of Physics Wuhan China (GRID:grid.49470.3e) (ISNI:***)

The ground and excited levels of the trimer (4He)3.are obtained theoretically by solving the 2-D Faddeev integral equation in the momentum space. In solving the equation, the direct matrix inversion method (I. M.) is used instead of the iteration and Pade approximate method. The new HFD-B Aziz potential ν is used in the calculation.

关键词： Trimer Faddeev equation matrix inversion method

THE NON-DIFFERENTIABILITY OF A CLASS OFFRACTAL INTERPOLATION FUNCTIONS

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Acta Mathematica Scientia 1999年第4期19卷 425-430页

作者：陈世荣 Department of physics Wuhan University Wuhan 430072 China

Hardin and Massopust([1]) introduced a class of fractal interpolation functions and calculated their Bouligand dimensions. This paper deals with the non-differentiability of these functions and shows some conditions under which they are nowhere differentiable. The basic technique here is based on the presentation the author obtains.

关键词： fractal interpolation iterated system nowhere differentiablity Hausdorff metric