Three-dimensional general magneto-electro-elastic finite element model for multiphysics nonlinear analysis of layered composites

In this paper, by defining a general potential energy for the multiphase coupled multiferroics and applying the minimum energy principle, the coupled governing equations are derived. This system of equations is then discretized as a general three-dimensional(3D) finite element(FE) model based on the COMSOL software. After validating the formulation, it is then applied to the analysis and design of the common sandwich structure of multiferroics composites. Under the typical static loading, the ef...     

基于线性调频机制的太赫兹无损检测成像技术

基于全固态电子器件和零中频机制，设计了基于调频连续波的太赫兹无损检测成像系统。所提系统的有效频率范围为9.375～13.75 GHz,经24倍频后自由空间中的频率范围为0.225～0.330 THz。采用单个喇叭天线与定向耦合器结合，实现收发一体，并利用光学透镜组对太赫兹波束进行准直聚焦。对准光系统的波束质量进行了优化，提高了系统的信噪比，确保了在现有参数条件下的最佳空间分辨率。同时，采用相位聚焦的方法对系统进行了非线性矫正，使得深度分辨率接近理论分辨率。系统采用直线扫描和旋转扫描组合的方式，实现了柱坐标三维数据的获取。利用所提系统对高压绝缘端子进行了检测评估，并重构了全视角透视图像，实现了目标三维结构在实空间和像空间的孪生对应。此外，所提系统能够准确地显示绝缘端子内部的异常区域，有助于直观地评估被检测目标的内部状态，进而可以进一步满足工业领域无损检测的需求。     

基于红外探测技术的汽车夜视系统研究

为了保证夜间及恶劣环境行车安全,提高驾驶员对前方目标识别的准确度,提出一种基于近红外成像技术的汽车夜视系统,该系统采用主动式近红外探测技术的车载夜视仪。系统主要由前端红外发射单元、红外线成像单元和图像显示单元组成。现场试验夜视系统识别漏检率为1.3%。实验结果表明传统车灯所辐射的大部分红外成分对夜间照明是无用的,可见光能效较低,而基于红外图像处理的汽车夜视系统能够有效地保证汽车安全驾驶。     

Theoretical prediction for effective properties and progressive failure of textile composites: a generalized multi-scale approach

Acta Mechanica Sinica - A generalized analytical model is developed to predict progressive failure behavior of several types of textile composites, including plain weave composites, twill weave...     

Manganese vanadium oxide hollow microspheres: a novel electrocatalyst for oxygen reduction reaction

Journal of Solid State Electrochemistry - The development of nonprecious catalysts with high electrocatalytic activities for the oxygen reduction reaction (ORR) has attracted considerable...     

Propagating anti-symmetrically coupled plasmons generation by electron beams

Propagating anti-symmetrically coupled plasmons that usually cannot be excited with incident light and radiate to far field can be efficiently generated by electron beams. An electron beam is proposed as a practical propagating anti-symmetrically coupled plasmon source due to that it couples differently to the surface plasmons than free radiation. Specifically, whispering-gallery anti-symmetrically coupled plasmons with the character of symmetrical coupled dipoles are excited by an electron beam in a nested ringlike waveguide, which is consistent with the dispersion of electron excited plasmons in an infinite-long nanowire pair.     

Kernel estimation for time series: An asymptotic theory

We consider kernel density and regression estimation for a wide class of nonlinear time series models. Asymptotic normality and uniform rates of convergence of kernel estimators are established under mild regularity conditions. Our theory is developed under the new framework of predictive dependence measures which are directly based on the data-generating mechanisms of the underlying processes. The imposed conditions are different from the classical strong mixing conditions and they are related to the sensitivity measure in the prediction theory of nonlinear time series.