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Quantitative measurement of local elasticity of SiO_x film by atomic force acoustic microscopy

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Chinese Physics B 2010年第8期19卷 449-455页

作者：何存富张改梅吴斌 College of Mechanical Engineering & applied Electronics technology Beijing University of Technology

In this paper the elastic properties of SiOx film are investigated quantitatively for local fixed point and qualitatively for overall area by atomic force acoustic microscopy （AFAM） in which the sample is vibrated at the ultrasonic frequency while the sample surface is touched and scanned with the tip contacting the sample respectively for fixed point and continuous measurements. The SiOx films on the silicon wafers are prepared by the plasma enhanced chemical vapour deposition （PECVD）, The local contact stiffness of the tip-SiOx film is calculated from the contact resonance spectrum measured with the atomic force acoustic microscopy. Using the reference approach, indentation modulus of SiOx film for fixed point is obtained. The images of cantilever amplitude are also visualized and analysed when the SiOx surface is excited at a fixed frequency. The results show that the acoustic amplitude images can reflect the elastic properties of the sample.

关键词： atomic force acoustic microscopy SiOx film contact resonance frequency local elasticity

Dexterity Analysis for Omni-directional Wheeled Mobile Manipulator Based on Double Quaternion

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Chinese Journal of Mechanical Engineering 2013年第3期26卷 585-593页

作者： DU Bin ZHAO Jing SONG Chunyu College of Mechanical Engineering and applied Electronics technology Beijing University of Technology

The unified analysis of omni-directional wheeled mobile manipulator(OWMM) through the dimensionally nonhomogeneous Jacobian matrix may lead to unreliable results. The existing researches focus on the integrated performance evaluation of OWMM, without taking the influence of velocity difference into consideration. This paper presents a new approach to formulate the dimensionally homogeneous Jacobian matrix and a new index for OWMM. First, the universal transformational matrix of the link coordinate frame is derived based on double quaternion. The degree of locomotion of a mobile platform and the degrees of manipulation of a manipulator are treated equally as the joints of a redundant composite robot. Then the integrated modeling of OWMM is established, and the non-dimensional Jacobian matrix is obtained from the above matrix. Next, by examining the concept of directional manipulability, a new index is proposed to evaluate the directional manipulability of OWMM along the specified task direction. Furthermore, for the same task and the time of simulation, the kinematic performance of the fixed base operation of the manipulator and the operation of OWMM are analyzed by numerical simulation. The results suggest that the proposed approach is equivalent to the method of traditional kinematic modeling, with the error of numerical solution being 10-7 , and the varying frequency of DMTR is higher than that of the condition number. This indicates that DMTR is more effective to reflect the variation of the task direction. The proposed method can be used to analyze the manipulating capability of OWMM, and has a simple structure and generality in the unified analysis of OWMM.

关键词： double quaternion homogeneous Jacobian mobile manipulator manipulability task direction

Localized Effect of Light Diffraction by Capillary Wave

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Chinese Physics Letters 2015年第11期32卷 43-51页

作者：苗扬聂松林 College of Mechanical Engineering and applied Electronics technology Beijing University of Technology

The localized effect of light diffracted by a capillary wave is discovered by changing the wave amplitude. The localized range is related to the wave number and the amplitude. The dependence of the half maximum localized angle on the wave number and amplitude is analytically derived. Meanwhile, the analytic angular distribution of the diffraction light in the localized range is obtained. Experiments are carried out to achieve diffraction patterns to confirm the localized effect and to measure the angular distribution of the diffraction light intensity as well as to determine the localized range scales corresponding to different wave amplitudes. Theoretical curves of the light intensity angular distribution and localized interval widths related to surface acoustic wave amplitudes are compared with the experimental data. The experimental results agree well with the theoretical prediction.

关键词： Localized Effect of Light Diffraction by Capillary Wave

Surface Characteristics of Rare Earth Treated Carbon Fibers and Interfacial Properties of Composites

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Journal of Rare Earths 2007年第4期25卷 462-468页

作者：徐志伟黄玉东宋元军张春华刘丽 Department of applied Chemistry Harbin Institute of Technology

Effect of rare earth treatment on surface physicochemical properties of carbon fibers and interfacial properties of carbon fiber/epoxy composites was investigated, and the interfacial adhesion mechanism of treated carbon fiber/epoxy composite was analyzed. It was found that rare earth treatment led to an increase of fiber surface roughness, improvement of oxygeaa-containing groups, and introduction of rare earth element on the carbon fiber surface. As a result, coordination linkages between fibers and rare earth, and between rare earth and resin matrix were formed separately, thereby the interlaminar shear strength （ILSS） of composites increased, which indicated the improvement of the interfacial adhesion between fibers and matrix resin resulting from the increase of carboxyl and carbonyl.

关键词： carbon fiber/epoxy composite interfacial properties X-ray photoelectron spectroscopy rare earths

The effect of the rotational excitation of NO on the stereodynamics for the reaction C(~3P)+NO(X^2Π)→CN(X^2Σ^+)+O(~3P)

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Chinese Physics B 2013年第6期22卷 338-343页

作者：马建军邹勇刘厚通 Department of applied Physics Anhui University of Technology

The stereodynamic properties of the reaction C （^3P）＋ NO （X2^П） →CN （X^2∑^＋）＋ O （^3P） in different rotational states of reactant NO are studied theoretically by using the quasiclassical trajectory method on ^2A″ and ^2A′ potential energy surfaces （PESs） at a collision energy of 0.06 eV. The vector properties in different rotational states on the two surfaces are discussed in detail. The results indicate that the rotational excitation of NO has considerable influence on the stereodynamic property of the reaction occurring on the two surfaces. At the same time, the calculated polarization-dependent differential cross sections （PDDCSs） in different initial rotational states manifest that products are strongly polarized at three scattering angles.

关键词： quasiclassical trajectory vector correlation rotational excitation

A new variable coefficient algebraic method and non-travelling wave solutions of nonlinear equations

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Chinese Physics B 2008年第11期17卷 3974-3984页

作者：陆斌张鸿庆 Department of applied Mathematics Dalian University of Technology

In this paper, a new auxiliary equation method is presented of constructing more new non-travelling wave solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than projective Riccati equation method. In order to illustrate the validity and the advantages of the method, （2＋1）-dimensional asymmetric Nizhnik-Novikov-Vesselov equation is employed and many new double periodic non-travelling wave solutions are obtained. This algorithm can also be applied to other nonlinear differential equations.

关键词： nonlinear partial differential equations non-travelling wave solutions asymmetric Nizhnik-Novikov- Vesselov equation

Superposition solitons in two-component Bose-Einstein condensates

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Chinese Physics B 2013年第5期22卷 168-174页

作者：王晓敏李秋艳李再东 Department of applied Physics Hebei University of Technology

We develop the Hirota bilinear method and obtain the exact one and two superposition soliton solutions for two- component Bose-Einstein condensates. The conversion of three kinds of solitons including the superposition solitons, bright-bright solitons, and dark-bright solitons is discussed. With the energy analysis, we find that the superposition soliton state is an excitation state for this system. Moreover, the collision of two superposition solitons is found to be elastic.

关键词： superposition solitons excitation states Hirota bilinear method

Surface behavior of pasted nickel electrodes with electrodeposited Co-Ce on substrate

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中国有色金属学会会刊：英文版 2006年第5期16卷 1148-1153页

作者：王殿龙王春雨戴长松姜兆华 Department of applied Chemistry Harbin Institute of Technology

MH/Ni battery for electro-vehicle has become a hot topic of studies. The Co-Ce alloys were electrodeposited on the nickel substrate to modify pasted nickel electrode substrate. SEM and XRD results show that the surface of the substrate contains Co(OH)2 and CoOOH film, and CV shows that modified film can improve electron conductivity capability. The state of charge (SOC) or state of discharge (SOD) curves indicate that Co-Ce modified substrate can enhance Ni electrode charge and discharge performance at high rate. The surface analysis by XPS shows that, the Co(Ⅱ)/Co(Ⅲ) ratio is 76.80/23.19 at the SOD, but the Co(Ⅱ)/Co(Ⅲ) ratio is 57.79/42.21 at the SOC, which indicates that the conductibility of electrodeposited Co-Ce alloys on the nickel substrate is enhanced because CoOOH and Co(OH)2 are created on the substrate surface. The modified surface with CoOOH and Co(OH)2 can enhance the conductibility of electrons between the substrate and active materials, and improve the high rate SOC and SOD ability.

关键词：镍电极 Co-Ce合金表面处理 MH/Ni电池 XRD SEM

Effects of geometric configuration on droplet generation in Y-junctions and anti-Y-junctions microchannels

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Acta Mechanica Sinica 2015年第5期31卷 741-749页

作者： Zhao-Miao Liu Li-Kun Liu Feng Shen College of Mechanical Engineering and applied Electronics technology Beijing University of Technology

Droplets generation in Y-junctions and anti-Yjunctions microchannels are experimentally studied using a high speed digital microscopic system and numerical *** configuration of a microchannel,such as Y-angle（90°,135°,-90° and-135°）,channel depth and other factors have been taken into *** is found that droplets generated in anti-Y-junctions have a smaller size and a shorter generation cycle compared with those in Yjunctions under the same experimental *** observing the internal velocity field,the vortex appearing in continuous phase in anti-Y-junctions is one of the key factors for the difference of droplet size and generation *** is found that droplet size is bigger and generation cycle is longer when the absolute angle value of the intersection between the continuous and the dispersed phases（i.e.,the angle between the main channel and the continuous phase or the dispersed phase channel） *** droplet＇s size is influenced by the Y-angle,which varies with the channel depth in *** Y-angle has a positive effect on the droplet generation cycle,but a smaller height-width ratio will enhance the impact of a continuous and dispersed phase＇s intersection angle on the droplet generation cycle in Y-junctions microchannels.

关键词： Microfluidics Y-junctions and anti-Yjunctions microchannels Y-angle Height-width ratio in cross section