共查询到20条相似文献,搜索用时 46 毫秒
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与质点连结的弹性杆的振动 总被引:10,自引:6,他引:4
用Laplace变换法求解了一端固定、一端与质点连结的弹性杆的振动问题,并详细讨论了几种极限情况下的运动图像,Laplace变换法对于同类问题普遍有效,而且不需要用到关于本征函数的完备性或(广义)正交性的定理。 相似文献
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牛顿和其他一些人早就观察到,当一束狭窄的白光通过放在适当位置的玻璃棱镜时,将被分解为各种颜色的光谱。他们又指出,若以适当角度插入另外一个棱镜、或会聚透镜、或一组反光镜,这些颜色又可重新混合成为白光。我找出了一个简单的演示颜 相似文献
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文章介绍了用示波器和信号发器搭配成的检测低通滤波器插入损耗的组合系统。列举了该系统对典型低通滤波器插入损耗的检测结果。 相似文献
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A six-node, plane-stress mixed finite element model has been developed by using Hamilton's energy principle for the natural vibrations of laminated composite beams. Continuity of the transverse stress and displacement fields has been enforced through the thickness of the laminated beam in the formulation for proper modelling. The transverse stress components have been invoked as the nodal degrees of freedom by applying elasticity relations. Natural frequencies of laminated composite beams obtained through the present formulation have been shown to be in good agreement with the data available in the literature. Various mode shapes have also been presented as benchmark solutions. 相似文献
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V.H. CORTÍNEZM.T. PIOVAN 《Journal of sound and vibration》2002,258(4):701-723
In this paper, a theoretical model is developed for the dynamic analysis of composite thin-walled beams with open or closed cross-sections. The present model incorporates, in a full form, the shear flexibility (bending and warping shear) as well as a state of initial stresses. This allows to study the free vibration and buckling problems in a unified fashion. An analytical solution of the developed equations is obtained for the case of simply supported thin-walled beams. Numerical examples are given to demonstrate the importance of the shear flexibility on the vibration and buckling behavior of the considered structures. 相似文献
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空心束虚阴极激励微波的主模式的研究 总被引:4,自引:3,他引:1
把虚阴极振荡激励微波的过程看成是一个时空振荡电流元激励微波的过程,在薄电荷层近似下,求得空心束虚阴极激励微波的主模式关系,并讨论了束几何位形与微波输出功率之间的关系。我们所确定的主模式与实验和粒子模拟的结果相符。 相似文献
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R. LEWANDOWSKI 《Journal of sound and vibration》2002,252(4):675-696
In this paper the non-linear vibrations of beams excited by vortex-shedding are considered. In particular, the steady state responses of beams near the synchronization region are taken into account. The main aerodynamic properties of wind are described by using the semi-empirical model proposed by Hartlen and Currie. The finite element method and the strip method are used to formulate the equation of motion of the system treated. The harmonic balance method is adopted to derive the amplitude equations. These equations are solved with the help of the continuation method which is very convenient to perform the parametric studies of the problem and to determine the response curve in the synchronization region. Moreover, the equations of motion are also integrated using the Newmark method. The results of calculations of several example problems are also shown to confirm the efficiency and accuracy of the presented method. The results obtained by the harmonic balance method and by the Newmark methods are in good agreement with each other. 相似文献
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本文在考虑到磁场和热压力的情况下,研究了对头碰相对论电子束在传输的过程中可能导致的几种电磁不稳定性和静电不稳定性,并给出了这些不稳定性出现的条件和增长率,利用不稳定性的激发条件,根据问题的要求可通过控制电子束的相对运动速度来激发或抑制这些不稳定性。
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用高速纹影诊断技术研究激光辐照下金属表面发生汽化的特征及蒸气发展运动过程,结合汽化模型给出了凝聚相表面温度与激光入射功率密度的关系。由实验得到了不同入射激光功率密度下汽化表面(凝聚相)温度,蒸气羽阵面速度,前驱空气冲击波速度。 相似文献
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本文提出并详细研究了应用两束“自陷”激光激发电子等离子体波(EPW)来维持等离子体拍频加速器(PBWA)中光束及其激发的EPW的会聚。文中导出了EPW饱和振幅所满足的方程,自洽地研究了泵浦光束的“自陷”条件,并解析地得到了最佳离谐条件及其对应的最佳初始等离子体密度以及EPW的最大振幅。在高斯型自陷泵浦光束情况下,文中应用数值法计算了EPW的横向分布。对于一定的离谐参量,此分布呈现出独特的性质。此外,本文还得到了由泵浦光束的非均匀性所产生的EPW电场的径向分量,并简要地讨论了它对PBWA中粒子加速的影响。
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