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Large scale domain switching around the tip of an impermeable stationary crack in ferroelectric ceramics driven by near-coercive electric field

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 121-126页

作者： CUI YuanQing ZHONG Zheng School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China

It is widely accepted that the singular term plays a leading role in driving domain switching around the crack tip of ferroelectric *** an applied electric field approaches or even exceeds the coercive one,however,non-singular terms are no longer negligible and the switching of a large or global scale takes *** analyze the large scale switching,one has to get a full asymptotic solution to the electric field in the vicinity of the crack *** a double cantilever beam specimen as an *** derivation of the full electric field is simplified as a mixed boundary value problem of an infinite strip containing a semi-infinite impermeable *** boundary value problem is solved by an analytic function and a conformal mapping to yield a full electric field solution in a closed *** on the full field solution,the large scale domain switching is *** switching zones predicted by the large and small scale switching models are illustrated and compared with each other near the tip of a stationary crack.

关键词： ferroelectric ceramics domain switching electric field analytic function impermeable crack strip

Stability switches and bogdanov-Takens bifurcation in an inertial two-neuron coupling system with multiple delays

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Science China(Technological Sciences) 2014年第5期57卷 893-904页

作者： SONG ZiGen XU Jian College of Information Technology Shanghai Ocean University School of Aerospace Engineering and Applied Mechanics Tongji University

In this paper,we investigate an inertial two-neural coupling system with multiple *** analyze the number of equilibrium points and demonstrate the corresponding pitchfork *** show that the system has a unique equilibrium as well as three equilibria for different values of coupling *** local asymptotic stability of the equilibrium point is studied using the corresponding characteristic *** find that multiple delays can induce the system to exhibit stable switching between the resting state and periodic *** regions with delay-dependence are exhibited in the parameter plane of the time delays employing the Hopf bifurcation *** obtain the global perspective of the system dynamics,stability and periodic activity involving multiple equilibria are investigated by analyzing the intersection points of the pitchfork and Hopf bifurcation curves,called the bogdanov-Takens(bT)*** homoclinic bifurcation and the fold bifurcation of limit cycle are obtained using the bT theoretical results of the third-order normal ***,numerical simulations are provided to support the theoretical analyses.

关键词： inertial two-neuron system multiple delays stability switches bogdanov-Takens bifurcation multiple stability

Green's function for T-stress of semi-infinite plane crack

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Applied Mathematics and Mechanics(English Edition) 2011年第8期32卷 973-980页

作者：崔元庆杨卫仲政 School of Aerospace Engineering and Applied Mechanics Tongji University Office of the Presidents Zhejiang University

Green’s function for the T-stress near a crack tip is addressed with an analytic function method for a semi-infinite crack lying in an elastical, isotropic, and infinite plate. The cracked plate is loaded by a single inclined concentrated force at an interior point. The complex potentials are obtained based on a superposition principle, which provide the solutions to the plane problems of elasticity. The regular parts of the potentials are extracted in an asymptotic analysis. based on the regular parts, Green’s function for the T-stress is obtained in a straightforward manner. Furthermore, Green’s functions are derived for a pair of symmetrically and anti-symmetrically concentrated forces by the superimposing method. Then, Green’s function is used to predict the domain-switch-induced T-stress in a ferroelectric double cantilever beam （DCb） test. The T-stress induced by the electromechanical loading is used to judge the stable and unstable crack growth behaviors observed in the test. The prediction results generally agree with the experimental data.

关键词： Green’s function T-stress complex variable function semi-infinite crack fracture mechanics

ANALYSIS OF FUNCTIONALLY GRADED PIEZOELECTRIC PLATE OF ARbITRARY GRADIENT DISTRIbUTION IN CYLINDRICAL bENDING

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ANALYSIS OF FUNCTIONALLY GRADED PIEZOELECTRIC PLATE OF ARBIT...

Stability switches and multi-stability coexistence in a delay-coupled neural oscillators system

第三届全国压电和声波理论及器件技术研讨会

作者： Wu-xiang LIU,Zheng ZHONG School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China

This paper studies an orthotropic functionally graded piezoelectric plate with arbitrary distributed material properties in cylindrical bending,which is simply supported and grounded on its two opposite *** state equations of the functionally graded piezoelectric material are obtained based on the state space approach and a Peano-baker series solution is obtained for the coupling electroelastic fields of the functionally graded piezoelectric plate subjected to mechanical and electric loads on its upper and lower *** influence of different material properties on the structural response of the plate is studied using the obtained solutions.

关键词： State space method functionally graded piezoelectric material cylindrical bending plate Peano-baker series

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Stability switches and multi-stability coexistence in a dela...

第一届全国神经动力学学术会议

作者： Zigen Song Jian Xu School of Aerospace Engineering and Applied Mechanics Tongji University

In this paper, we present a neural network system composed of two delay-coupled neural oscillators, where each of oscillators can be regarded as the dynamical system describing the average activities of neural populations. Analyzing the corresponding characteristic equation, the local stability of rest state is studied. The stability

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交通环境有毒气体的检测技术研究

计算机工程与应用 2010年第8期46卷 202-204页

作者：杨莉王磊同济大学电子与信息工程学院上海200092 同济大学航空航天与力学学院上海200092

针对交通环境中毒害较大的CO、NO2和CH4三种气体,优选金属氧化物半导体气体传感器构成阵列,并对bP网络进行改进,采用有弹回的bP算法,构造了电子鼻系统。实验结果表明,系统能够以较高的精度检测出交通环境中三种有毒气体的浓度。

关键词： bP网络交通污染传感器阵列模式识别

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随机阻尼Rattling系统模型

噪声与振动控制 2009年第6期29卷 143-146,169页

作者：孙宜强冯奇同济大学航空航天与力学学院上海200092

Rattling振动是齿轮传动过程中由于啮合间隙的存在而产生的一种有害的振动。主要从理论上研究带有随机阻尼的Rattling振动系统,采用非高斯截断技术导出一个由平均映射描述的随机模型,并通过试验验证了结论的合理性,该模型可用于模拟齿... 详细信息

Rattling振动是齿轮传动过程中由于啮合间隙的存在而产生的一种有害的振动。主要从理论上研究带有随机阻尼的Rattling振动系统,采用非高斯截断技术导出一个由平均映射描述的随机模型,并通过试验验证了结论的合理性,该模型可用于模拟齿轮箱的噪声源。

关键词：振动与波 Rattling系统随机阻尼非高斯截断平均映射