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51.
热/均布载荷下双材料悬臂梁的解析解 总被引:1,自引:0,他引:1
基于弹性介质的二维本构关系和热传导理论,采用逆解法,研究了双材料悬臂梁在热/机械载荷作用下的问题,通过假设双材料悬臂梁构件的应力函数,利用应力、位移边界条件和连续性条件,给出了其位移、应力分布的表达式。 相似文献
52.
In this paper, the off-axial acoustic scattering of a high-order Bessel vortex beam by a rigid immovable (fixed) sphere is investigated. It is shown here that shifting the sphere off the axis of wave propagation induces a dependence of the scattering on the azimuthal angle. Theoretical expressions for the incident and scattered field from a rigid immovable sphere are derived. The near- and far-field acoustic scattering fields are expressed using partial wave series involving the spherical harmonics, the scattering coefficients of the sphere, the half-conical angle of the wave number components of the beam, its order and the beam-shape coefficients. The scattering coefficients of the sphere and the 3D scattering directivity plots in the near- and far-field regions are evaluated using a numerical integration procedure. The calculations indicate that the scattering directivity patterns near the sphere and in the far-field are strongly dependent upon the position of the sphere facing the incident high-order Bessel vortex beam. 相似文献
53.
弹性地基梁振动特性的近似分析方法 总被引:4,自引:1,他引:4
文中介绍了用模态摄动法分析复杂情况下弹性地基梁动力特性的近似方法。这一方法中可考虑纵向钢筋以及变地基弹性系数对弹性地基梁振动特性的影响,通过算例说明了这一方法的有效性。 相似文献
54.
移动的线源平稳随机荷载激励下梁的随机响应 总被引:3,自引:0,他引:3
利用广义Duhamel积分和积分变换,研究了粘弹性Kelvin地基上无限长梁在运动的线源平稳随机荷载作用下的随机响应.发现此时梁的挠度响应为非平稳随机过程.通过引入随动坐标系,建立了有明确物理意义的随动谱分析方法,使随机位移响应在随动坐标系下成为平稳随机过程 相似文献
55.
本文考虑轴向应力波效应,利用分叉理论研究各种支承半无限长弹塑性梁的动态屈曲问题。在轴向阶梯载荷和脉冲载荷冲击下得到了梁的临界屈曲载荷及初始屈曲模态。其结果与实验现象相一致。同时也为研究结构动态屈曲问题提供了有效途径。 相似文献
56.
Mihail I. Petrov Sergey V. Sukhov Andrey A. Bogdanov Alexander S. Shalin Aristide Dogariu 《Laser \u0026amp; Photonics Reviews》2016,10(1):116-122
We demonstrate both analytically and numerically the existence of optical pulling forces acting on particles located near plasmonic interfaces. Two main factors contribute to the appearance of this negative recoil force. The interference between the incident and reflected waves induces a rotating dipole with an asymmetric scattering pattern, while the directional excitation of surface plasmon polaritons (SPPs) enhances the linear momentum of scattered light. The strongly asymmetric SPP excitation is determined by spin–orbit coupling of the rotating dipole and surface plasmon polariton. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. We derive analytical expressions for the force acting on dipolar particles placed in the proximity of plasmonic surfaces. Analytical expressions for this pulling force are derived within the dipole approximation and are in excellent agreement with results of electromagnetic numerical calculations. The forces acting on larger particles are analyzed numerically, beyond the dipole approximation.
57.
Cheng Hung Chu Ming Lun Tseng Jie Chen Pin Chieh Wu Yi‐Hao Chen Hsiang‐Chu Wang Ting‐Yu Chen Wen Ting Hsieh Hui Jun Wu Greg Sun Din Ping Tsai 《Laser \u0026amp; Photonics Reviews》2016,10(6):986-994
We propose all‐dielectric metasurfaces that can be actively re‐configured using the phase‐change material Ge2Sb2Te5 (GST) alloy. With selectively controlled phase transitions on the composing GST elements, metasurfaces can be tailored to exhibit varied functionalities. Using phase‐change GST rod as the basic building block, we have modelled metamolecules with tunable optical response when phase change occurs on select constituent GST rods. Tunable gradient metasurfaces can be realized with variable supercell period consisting of different patterns of the GST rods in their amorphous and crystalline states. Simulation results indicate a range of functions can be delivered, including multilevel signal modulating, near‐field coupling of GST rods, and anomalous reflection angle controlling. This work opens up a new space in exploring active meta‐devices with broader applications that cannot be achieved in their passive counterparts with permanent properties once fabricated.
58.
根据广义惠更斯-菲涅尔原理和Collins公式,基于复高斯函数展开法,推导出椭圆偏振的高斯-谢尔模型光束经过矩形光阑衍射后的交叉谱密度公式,结合斯托克斯矢量理论推导了椭圆偏振高斯-谢尔模型光束在接收平面的光强、偏振度、方位角和椭圆度的表达式,数值分析了光阑的孔径遮拦比对光强、偏振度及方位角和椭圆度的影响.结果表明,光阑的孔径遮拦比在近场区对经过光阑后椭圆偏振高斯-谢尔模型光束的光强和偏振特性有显著影响;随着传输距离的增大,光强和偏振特性受孔径遮拦比的影响减小,光强和偏振特性变化平稳. 相似文献
59.
Vando Narciso 《Mathematical Methods in the Applied Sciences》2015,38(4):775-784
This paper is concerned with the existence of a global attractor for the nonlinear viscoelastic beam equation with past history memory where g(ut) is a damping like | ut | rut and f(u) is a source term like | u | αu ? | u | βu, by considering 0 ≤ β < α and r > 0. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
60.
Nadia Balucani Laura Cartechini Zahra Homayoon Joel M. Bowman 《Molecular physics》2015,113(15-16):2296-2301
Following a recent investigation on the N(2D) + H2O reaction [Homayoon et al., J. Phys. Chem. Lett. 5, 3508 (2014)], we report on an experimental and theoretical study of the isotopologue N(2D) + D2O reaction. Crossed molecular beam (CMB) experiments were conducted at a collision energy of 10.3 kcal mol–1. Quasiclassical trajectory calculations were performed on a recent potential energy surface to derive the centre-of-mass functions necessary to simulate the CMB laboratory distributions. Excellent agreement was found. The importance of the channel leading to HON/DON was confirmed. The inclusion of this channel, in addition to that leading to the isomer HNO/DNO, can affect the models considering the coupling between nitrogen and oxygen chemistry in the upper atmosphere of Titan. 相似文献