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Upper Bounds of the Rates of Decay for Solutions of the Boussinesq Equations

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Acta Mathematicae Applicatae Sinica 2011年第1期27卷 105-114页

作者： Ying Liu fundamental department of the academy of armored force engineering Bejing 100072 China

In this paper, upper bounds of the L2-decay rate for the Boussinesq equations are considered. Using the L2 decay rate of solutions for the heat equation, and assuming that the solutions of the Boussinesq equations are smooth, we obtain the upper bounds of L2 decay rate for the smooth solutions and difference between the solutions of the Boussinesq equations and those of the heat system with the same initial data. The decay results may then be obtained by passing to the limit of approximating sequences of solutions. The main tool is the Fourier splitting method.

关键词： the Boussinesq equations L2 decay Fourier splitting method

Existence,Orbital Stability and Instability of Solitary Waves for Coupled BBM Equations

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 1-10页

作者： Li-wei Cui fundamental department The Academy of Armored Force Engineering Beijing 100072 China

This paper is concerned with the orbital stability/instability of solitary waves for coupled BBM equations which have Hamiltonian form. The explicit solitary wave solutions will be worked out first. Then by detailed spectral analysis and decaying estimates of solutions for the initial value problem, we obtain the orbital stability/instability of solitary waves.

关键词： Solitary wave orbital stability/instability spectral analysis decaying estimate

The surface plasmon polariton dispersion relations in a nonlinear-metal-nonlinear dielectric structure of arbitrary nonlinearity

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Chinese Physics B 2011年第3期20卷 392-397页

作者：刘炳灿于丽逯志欣 School of Science Beijing University of Posts and Telecommunications department of fundamental Courses Academy of Armored Force Engineering

The analytic surface plasmon polaritons （SPPs） dispersion relation is studied in a system consisting of a thin metallic film bounded by two sides media of nonlinear dielectric of arbitrary nonlinearity is studied by applying a generalised first integral approach. We consider both asymmetric and symmetric structures. Especially, in the symmetric system, two possible modes can exist： the odd mode and the even mode. The dispersion relations of the two modes are obtained. Due to the nonlinear dielectric, the magnitude of the electric field at the interface appears and alters the dispersion relations. The changes in SPPs dispersion relations depending on film thicknesses and nonlinearity are studied.

关键词： surface plasmon polariton nonlinear dispersion relation planar waveguide

Design and manufacture of intelligent Cu-based wet friction materials

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中国有色金属学会会刊：英文版 2004年第5期14卷 864-869页

作者：丁华东韩文政傅苏黎杜建华遇元宏 department of Materials Science and engineering Academy of Armored Force Engineering Beijing 100072 China department of Discipline Academy of Armored Force Engineering Beijing 100072 China

The friction sheets working process was analyzed. It is found that its characteristic is microregion instantaneous high temperature and the current cooling method, making the sheets cooled by the lubricating oil flowing through the friction surface, is not very efficient. Then, intelligent materials concept was introduced, the component and microstructure of intelligent Cu-based friction materials were designed, and the intelligent Cu-based wet friction materials as well as sheets were manufactured. And the intelligent friction materials working principle, i.e. the materials cooling the friction microregion in real time or the friction sheets cutting the peak value of microregion instantaneous high temperature during friction process, was given depending on the characteristics of the materials’ and friction sheets’ working process. Finally, it is indicated that the intelligent friction sheets excell the currently used friction sheets in properties, including anti-heating property, anti-wearing property as well as friction characteristic.

关键词：智能金属汽车齿轮箱摩擦片铜基合金

Tribology properties of composite layer of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing

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中国有色金属学会会刊：英文版 2004年第z1期14卷 315-318页

作者： MA Shi-ning HU Chun-hua LI Xin QIU Ji department of Materials Science and engineering Academy of Armored Force Engineering Beijing 100072 China Department of Materials Science and EngineeringAcademy of Armored Force Engineering Beijing 100072 China Department of Materials Science and EngineeringAcademy of Armored Force Engineering Beijing 100072 China Department of Materials Science and EngineeringAcademy of Armored Force Engineering Beijing 100072 China

Composite layer with nitrocarbonide and sulfide was made on the surface of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing. The composite layer is composed of sulfide layer, nitrocarbonide hypo-surface layer and its diffusing layer, the size of sulfide globular grains distributing equably on the surface is in nano-micron-scale, and the phase structure of the composite layer is composed of FeS, FeS1-x, Fe2C and Fe3N. Under oil lubrication, sulphurized surface shows good scuffing-resistance only under low velocity, and nitrocarburized and sulphurized surface greatly improves the scuffing-resistance and wear-resistance of CrMoCu alloy cast iron, its integrated friction and wear properties are better than those of the plain and sulphurized surfaces under all the velocities.

关键词： ion nitrocarburizing ion sulphurizing combined treatment friction and wear properties

Surface nanostructure formation mechanism of 45 steel induced by supersonic fine particles pombarding

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Journal of University of Science and Technology Beijing 2008年第5期15卷 561-567页

作者： Dema Ba Shining Ma Changqing Li Fanjun Meng department of Remanufacture engineering Academy of Armored Force Engineering Beijing 100072 China

By means of supersonic fine particles bombarding （SFPB）,a nanostructured surface layer up to 15 μm was fabricated on a 45 steel plate with ferrite and pearlite phases. To reveal the grain refinement mechanism of SFPB-treated 45 steel,microstructure features of various sections in the treated surface were systematically characterized by X-ray diffraction （XRD）,scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. Grain size increases with an increase of depth from the treated surface. Plastic deformation and grain refinement processes are accompanied by an increase in strain. Plastic deformation in the proeutectoid ferrite phases has precedence over the pearlite phases. Grain refinement in the ferrite phases involves： the onset of dislocation lines （Dls）,dislocation tangles （DTs） and dense dislocation walls （DDWs） in the original grains; the formation of fine lamellar and roughly equiaxed cells separated by DDWs; by dislocation annihilation and rearrangement,the transformation of DDWS into subboundaries and boundaries and the formation of submicron grains or subgrains; the successive subdivision of grains to finer and finer scale,resulting in the formation of highly misoriented nano-grains. By contrast,eutectoid cementite phase accommodated strain in a sequence as follows： onset of elongated,bended and shear deformation under deformation stress of ferrites,short and thin cementites with a width of about 20-50 nm and discontinuous length were formed. Shorter and thinner cementites were developed into ultra-fine pieces under the action of high density dislocation and strains. At the top surface,some cementites were decomposed under severe plastic deformation. Experimental evidences and analysis indicate that surface nanocrystallization of 45 steel results from dislocation activities,high strains and high strain rate are necessary for the formation of nanocrystallites.

关键词： surface nanocrystallization grain refinement mechanism microstructure 45 steel

Higher order asymptotic fields for mode Ⅰ crack in functionally gradient material

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中国有色金属学会会刊：英文版 2005年第2期15卷 473-477页

作者：戴耀燕秀发 department of engineering Mechanics Academy of Armored Force Engineering Beijing 100072 China

Higher order stress fields for a mode Ⅰ crack perpendicular to the direction of property variation in a functionally gradient material(FGM), which has an exponential variation of elastic modulus along the gradient direction, were obtained through an asymptotic analysis. The Poisson’s ratio of the FGMs was assumed to be constant throughout the analysis. The first five terms in the asymptotic expansions of crack tip stress fields were derived to bring out the influence of nonhomogeneity on the structure of the stress field explicitly. The analysis reveals that only the higher order terms in the expansion are influenced by the material nonhomogeneity. Moreover, it can be seen from expressions of higher order stress fields that at least three terms must be considered in the case of FGMs in order to explicitly account for the nonhomogeneity effects on the structure of crack tip stress fields.

关键词：功能梯度材料同质性高阶应力场渐近膨胀

Characteristic analysis of magnetorheological fluid based on different carriers

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Journal of Central South University 2008年第S1期15卷 252-255页

作者：张建张进秋贾进峰 department of Technical Support engineering Academy of Armored Force Engineering

In order to prepare special MRFs to satisfy the demands of tracked vehicle,two different carrier fluids were used to prepare *** of MRF,which are based on carrier of special shock absorption fluid and 45# transformer oil,was *** characteristics of these samples were tested and *** results show that Tween-80 and Span-80 can improve the sedimentary stability,and the larger mass fraction can also increase the sedimentary *** 45# transformer oil instead of special shock absorption fluid as a carrier of MRF,the shear yield stress remains nearly constant but the viscosity and the sedimentary stability are *** MRF with diameter of 2.73 μm shows better sedimentary stability than that of the MRF with diameter of 2.30 μm,or 4.02 μ*** acid obviously improves sedimentary stability and off-state viscosity,but has no function on the shear yield *** magnetic field of 237 kA/m,the shear yield stress of MRF based on special shock absorption fluid is 18.34 kPa and the shear yield stress of MRF based on 45# transformer oil is 14.26 kPa.

关键词： magnetorheological fluid 45# transformer oil shear yield stress off-state viscosity sedimentary stability

Polaron effects in cylindrical GaAs/Al_xGa_(1-x)As core-shell nanowires

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Chinese Physics B 2017年第9期26卷 415-420页

作者：孙慧刘炳灿田强 department of Physics Beijing Normal University department of fundamental Courses Academy of Armored Forces Engineering

By the fractal dimension method, the polaron properties in cylindrical GaAs/AlxGa1-xAs core-shell nanowire are explored. In this study, the polaron effects in GaAs/AlxGa1-xAs core-shell nanowire at different values of shell width and aluminum concentration are discussed. The polaron binding energy, polaron mass shift and fractal dimension parameter are numerically worked out each as a function of core radius. The calculation results show that the binding energy and mass shift of the polaron first increase and then decrease as the core radius increases, forming their corresponding maximum values for different aluminum concentrations at a given shell width. Polaron problems in the cylindrical GaAs/AlxGa1-xAs core-shell nanowire are solved simply by using the fractal dimension method to avoid complex and lengthy calculations.

关键词： core-shell nanowire core radius polaron effects fractal dimension