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A stabilized complementarity formulation for nonlinear analysis of 3D bimodular materials

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Acta Mechanica sinica 2016年第3期32卷 481-490页

作者： L.Zhang h.w.Zhang J.wu b.Yan Department of Engineering Mechanics College of AerospaceEngineering Chongqing University state Key Laboratory of structural Analysis for IndustrialEquipment Dalian University of Technology

bi-modulus materials with different mechanical responses in tension and compression are often found in civil,composite, and biological engineering. Numerical analysis of bimodular materials is strongly nonlinear and convergence is usually a problem for traditional iterative schemes. This paper aims to develop a stabilized computational method for nonlinear analysis of 3D bimodular materials. based on the parametric variational principle, a unified constitutive equation of 3D bimodular materials is proposed, which allows the eight principal stress states to be indicated by three parametric variables introduced in the principal stress *** original problem is transformed into a standard linear complementarity problem（LCP） by the parametric virtual work principle and a quadratic programming algorithm is developed by solving the LCP with the classic Lemke＇s algorithm. Update of elasticity and stiffness matrices is avoided and, thus, the proposed algorithm shows an excellent convergence behavior compared with traditional iterative *** examples show that the proposed method is valid and can accurately analyze mechanical responses of 3D bimodular materials. Also, stability of the algorithm is greatly improved.

关键词： bimodular materials Non-smooth stressstrain relationship Parametric variational principle Complementarity

Review of deployment technology for tethered satellite systems

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Acta Mechanica sinica 2018年第4期34卷 754-768页

作者： b.s.Yu h.wen D.P.Jin state Key Laboratory of Mechanics and Control of Mechanical structures Nanjing University of Aeronautics and Astronautics

Tethered satellite systems（Tsss） have attracted significant attention due to their potential and valuable applications for scientific research. with the development of various launched on-orbit missions, the deployment of tethers is considered a crucial technology for operation of a Tss. both past orbiting experiments and numerical results have shown that oscillations of the deployed tether due to the Coriolis force and environmental perturbations are inevitable and that the impact between the space tether and end-body at the end of the deployment process leads to complicated nonlinear phenomena. hence, a set of suitable control methods plays a fundamental role in tether deployment. This review article summarizes previous work on aspects of the dynamics, control, and ground-based experiments of tether deployment. The relevant basic principles, analytical expressions, simulation cases, and experimental results are presented as well.

关键词： Tethered satellite Deployment Dynamics Control Experiment

Electronic structure and magnetic properties of rare-earth perovskite gallates from first principles

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Chinese Physics b 2017年第1期26卷 375-385页

作者： A Dahani h Alamri b Merabet A Zaoui s Kacimi A boukortt M bejar Laboratoire de Physique Computationnelle des Materiaux Universite Dfillali Liabes de Sidi Bel-Abbes Sidi Bel-Abbes 22000 Algeria Universite Moulay Tahar Faculte de Technologie Saida 20000 Algeria Umm AI-Qura University Physics Department-University College Makkah Saudi Arabia Universite Mustapha stambouli Faculte de Technologie Mascara 29000 Algeria Elaboration Characterization Physico-Mechanics of Materials and Metallurgical Laboratory ECP3M Faculty of Sciences and Technology Abdelhamid Ibn Badis University of Mostaganem Mostaganem 27000 Algeria Laboratoire de Physique Appliquee Faculte des Sciences Universite de Sfax Sfax 3000 Tunisia

The density functional calculation is performed for centrosymmetric（La–Pm） GaO3 rare earth gallates, using a full potential linear augmented plane wave method with the LsDA and LsDA＋U exchange correlation to treat highly correlated electrons due to the very localized 4f orbitals of rare earth elements, and explore the influence of U = 0.478 Ry on the magnetic phase stability and the densities of states. LsDA＋U calculation shows that the ferromagnetic（FM） state of RGaO3 is energetically more favorable than the anti-ferromagnetic（AFM） one, except for LaGaO3 where the NM state is the lowest in energy. The energy band gaps of RGaO3 are found to be in the range of 3.8–4.0 eV, indicating the semiconductor character with a large gap.

关键词： DFT+U+sO strongly correlated electron systems magnetism rare earth gallates perovskites

Microstructures and Mechanical Properties of Al/Mg Alloy Multilayered Composites Produced by Accumulative Roll bonding

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Journal of Materials science & Technology 2011年第1期27卷 15-21页

作者： h.s. Liu b. Zhang G.P. Zhang shenyang National Laboratory for Materials science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education School of Materials & Metallurgy Northeastern University Shenyang 110004 China

Al/Mg alloy multilayered composites were produced successfully at the lower temperature（280 C） by accumulative roll bonding（ARb） processing *** microstructures of Al and Mg alloy layers were characterized by scanning electron microscopy and transmission electron *** hardness and three-point bending tests were conducted to investigate mechanical properties of the *** is found that Vickers hardness,bending strength and stiffness modulus of the Al/Mg alloy multilayered composite increase with increasing the ARb *** and crack propagation along the interface are the two main failure modes of the multilayered composite subjected to bending *** and fracture mechanisms of the composite are analyzed.

关键词： Accumulative roll bonding(ARb) Al/Mg alloy multilayered composite Ultra-fine grains hardness bending properties

Molybdenum Disulphide Tape saturable Absorber for Mode-Locked Double-Clad Ytterbium-Doped All-Fiber Laser Generation

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Chinese Physics Letters 2016年第11期33卷 43-46页

作者： M.F.M.Rusdi A.A.Latiff E.hanafi M.b.h.Mahyuddin h.shamsudin K.Dimyati s.w.harun Department of Electrical Engineering Faculty of EngineeringUniversity of Malaya Photonics Research Center University of Malaya

we demonstrate the generation of passive mode-locked double-clad ytterbium-doped fiber laser operating in a 1-micron region. we prepare the saturable absorber from commercial crystal of molybdenum disulphide （Mos2 ）. without chemical procedure, the Mos2 is mechanically exfoliated by using a clear scotch tape. A few layers of Mos2 flakes are obtained on the tape. Then, a piece of 1× 1 mm tape containing Mos2 thin flakes is inserted between two fiber ferrules and is integrated in the ring cavity. stable mode-locking operation is attained at 1090nm with a repetition rate of l3.2 Mhz. Our mode-locked laser has a maximum output power of 2Omw with 1.48nJ pulse energy. These results validate that the Mos2 has a broad operating wavelength which covers the 1-micron region, and it is also able to work in a high-power cavity.

关键词： mode of in is for

OPTICAL ChARACTERIZATION OF TiO_2 ThIN FILM ON sILICON sUbsTRATE DEPOsITED bY DC REACTIVE MAGNETRON sPUTTERING

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Acta Metallurgica sinica(English Letters) 2005年第3期18卷 194-198页

作者： h.Q.wang h.shen D.C.ba b.w.wang L.s.wen D.Chen schoolofMechanismandAutomobile ShenyangInstituteofAeronauticalEngineeringShenyang110034Ghina／／MechanismandAeronauticalCollegeNortheasternUniversityShenyang110004China TheschoolofPhysicsandEngineering ZhongshanUniversityGuangzhou510275Ghina MechanismandAeronauticalCollege NortheasternUniversityShenyang110004China GuangzhouInstimdeofEnergyConversion Guangzhou510070China InstituteofMetalResearch TheChineseAcademyofSciencesShenyang110016China MaterialandscienceEngineeringAcademy SouthChinaUniversityofTechnologyGuangzhou510641China

TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterizatio n of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC re active magnetron sputtering process from Ti target. The reflectivity of the film s was measured by UV-3101PC, and the index of refraction (n) and extinction coef ficient (k) were measured by n & k Analyzer 1200.

关键词： optical characterization TiO2 thin film DC reactive magnetron sputtering n & k

An Investigation of Ionic Flows in a sphere-Plate Electrode Gap

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Plasma science and Technology 2013年第10期15卷 1012-1019页

作者： h.Z.ALIsOY s.ALAGOZ G.T.ALIsOY b.b.ALAGOZ Department of Electrical-Electronics Inonu University Department of Physics Inonu University Department of Mathematics Inonu University

This paper presents analyses of ion flow characteristics and ion discharge pulses in a sphere-ground plate electrode system. As a result of variation in electric field intensity in the electrode gap, the ion flows towards electrodes generate non-uniform discharging pulses. Inspection of these pulses provides useful information on ionic stream kinetics, the effective thickness of ion cover around electrodes, and the timing of ion clouds discharge pulse sequences. A finite difference time domain （FDTD） based space-charge motion simulation is used for the numerical analysis of the spatio-temporal development of ionic flows following the first Townsend avalanche, and the simulation results demonstrate expansion of the positive ion flow and compression of the negative ion flow, which results in non-uniform discharge pulse characteristics.

关键词： ion flow FDTD simulation space charge motion

Deng-Fan Potential for Relativistic spinless Particles—an Ansatz solution

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Communications in Theoretical Physics 2012年第3期57卷 339-342页

作者： h.hassanabadi b.h.Yazarloo s.Zarrinkamar h.Rahimov Physics Department Shahrood University of Technology Young Researchers Club Garmsar BranchIslamic Azad University Computer Engineering Department Shahrood University of Technology

Deng-Fan potential originally appeared many years ago as an attractive proposition for molecular systems. On the contrary to the ground state of one-dimensional schr6dinger equation, this potential fails to admit exact analytical solutions for arbitrary quantum number in both relativistic and nonrelativistic regime. because of this complexity, there exists only few papers, which discuss this interesting problem. here, using an elegant ansatz, we have calculated the system spectra as well as the eigenfunctions in the general case of unequal vector and scalar potentials under Klein-Gordon equation.

关键词： Klein Gordon equation Deng Fan potential D-dimensional space Ansatz method

New results on stability criteria for neural networks with time-varying delays

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Chinese Physics b 2011年第5期20卷 163-173页

作者： O.M.Kwon J.w.Kwon s.h.Kim school of Electrical Engineering Chungbuk National University410 SungBong-RoHeungduk-guCheongju 361-763Republic of Korea Department of Computer Engineering Kyungwon UniversitySan 65Sujung-guSungnam 461-701Republic of Korea school of Integrated Technology College of EngineeringYonsei University50 Yonsei-RoSeodaemun-guSeoul 120-749Republic of Korea

In this paper, the problem of stability analysis for neural networks with time-varying delays is considered. by constructing a new augmented Lyapunov-Krasovskii＇s functional and some novel analysis techniques, improved delaydependent criteria for checking the stability of the neural networks are established. The proposed criteria are presented in terms of linear matrix inequalities （LMIs） which can be easily solved and checked by various convex optimization algorithms. Two numerical examples are included to show the superiority of our results.

关键词： neural networks time-varying delays stability Lyapunov method