振动

When the frequency or the amplitude of the vibration is high, the final segregation efficiency is still low, but the segregation is unstable. An optimum operating point with a moderate frequency and a moderate amplitude of the vibration exists in the process of segregation in Brazil nut problem.

当振动频率或振动幅度较小时，颗粒整体分离效果都较差，但分离的稳定性较好，当振动频率或振动幅度较大时，整体分离效果仍然较差，同时分离的稳定性也较差，振动分离过程中存在一个频率和振幅适中的最优操作点。

This paper mainly consists of three parts:(1) Based on the Reddy's higher-order shear deformation plate theory and general von Kármán-type equations, put forward the governing equations of pre- and post-buckled vibration of several hybrid FGM plate forms which have not been studied adequately, triumphantly applying the perturbation technique combined with Galerkin method into equations solving, and get the comparatively simple result forms with complicated deduction at last;(2) As a new type of materials, piezoelectric fiber reinforced composite actuators were applied to optimal vibration control, interrelated informatons be depicted in this paper;(3) During the investigative cource, some factors not been considered adequently in other researches were discussed fully in the postbuckled vibration analysis, such as the temperature-dependent material coefficients, heat conduction and nonlinear vibration characteristic etc.

本文的研究工作主要包括：(1)基于Reddy高阶剪切变形板理论和广义Kármán型方程，给出了几类现有研究成果较少或没有彻底解决的FGM混合板结构的屈曲前和屈曲后振动特性研究的控制方程，成功将摄动-Galerkin混合法应用于求解过程，并给出了各控制方程相对直观且易于计算的解析解形式；(2)单向压电纤维增强复合材料(Piezoelectric Fiber Reinforced Composite，简称PFRC)是一种新型压电材料，本文将其应用到了结构振动控制研究当中，发现通过压电纤维体积含量的选择可以实现混合板结构的优化振动控制；(3)围绕几种有代表性的FGM混合板结构，讨论其屈曲后的振动特性，在分析中同时考虑热传导，材料物性参数的温度相关性，以及机/热/电荷载耦合效应对非线性振动特性的影响，最后给出了大量数值计算结果。

The soil cutting experiment indicates that the interior friction angle and the shear intensity of soil is reduced;and the maximum principal stress is decreased due to the vibration load;it induces the decrease of digging resistance.

从理论上研究了振动掘削岩土的减阻机理，土壤剪切试验结果表明，振动载荷能够使土壤的内摩擦角变小、抗剪强度下降、最大主应力值减小，从而导致挖掘阻力降低；对土壤在静态载荷和振动载荷作用下的失效过程进行了对比仿真实验研究，可知土壤在振动加载的条件下强度显著下降，并提前于相同条件的静态加载而破坏，同时跟踪X方向的载荷发现，振动掘削最大掘削阻力可降低50%。

Results show that vertical ground vibrations are generally greater than the lateral vibrations in the area vicinity to the central line of the railway, and decrease rapidlywith an increase in the distance to the central line.

结果表明：列车通过时，地面的竖向振动普遍比横向振动大；在靠近线路中心的区域，竖向振动随到线路距离的增加很快衰减；地面的横向振动有时比竖向的大，计算时不应忽略；地面振动强度和传播范围随地基弹性模量和埋深增加而减小。

For solving the problem that mixing quality,vibration intensity and working reliability can not be ensured at the same time in the study of vibratory mixing,authors put forward a new vibratory mixing technique.

针对振动搅拌技术中搅拌质量、振动强度和机器工作可靠性不能兼顾的问题，在前期试验研究基础上，提出一种新的振动搅拌技术，认为以搅拌轴和搅拌叶片作为振动活化源，振动和强制搅拌相结合的实施方案是合理的。

Aim at the shortage of vertically additive method by which we can't discuss forced oscillations of systems of partial functional differential equations,we directly use the oscillatory definition,Green's formula and boundary condition of homogeneous Neumann to change the oscillatory problem of solutions to a class of systems of quasilinear parabolic equations of neutral type into the problem of which functional differential inequality haven't eventually positive solution.

针对垂直相加法无法讨论泛函偏微分方程组的强迫振动性的不足，直接利用振动的定义、Green公式以及齐次Neumann边界条件把中立型抛物微分方程组的振动问题转化为泛函微分不等式不存在最终正解的问题，然后利用最终正解的定义及上下极限得到了在齐次Neumann边界条件下判别其所有解振动或全振动的充分条件。

The specific contents are as follows:Firstly, the causes of energy balance method result has some errors is analyzed. Then energy balance method is improved from the following aspects: the wind power input, the conductor self-damping, the damper dissipated power and vibration solution of Stockbridge dampers-conductor coupling system. So that improved energy balance method can consider more influential factors to enhance accuracy.

本文对输电线的微风振动控制和次档距振荡进行了多方面的研究，主要包括能量平衡法的改进、防振锤-输电线耦合系统的振动求解、阻尼线的耗能计算理论、微风振动的室内模拟试验、分裂导线微风振动的精细计算理论、多分裂导线的最大次档距和阻尼间隔棒优化布置等几部分，具体如下：首先分析了微风振动传统计算方法能量平衡法计算误差较大的原因，分别从风能输入功率、输电线自阻尼功率、防振锤消耗功率、输电线-防振锤耦合体系的振动求解等方面，对能量平衡法进行了改进，使能量平衡法可以考虑更多的影响因素以提高求解精度。

Experimental research on the vibration of single slab and multi ones set in the arch ring is carried out in the first time. Slab vibration divisions along the water flow are proposed and their lists are determined. Laws of vibration distribution along water flow, across the arch ring, in time zone and frequency one are established. The most dangerous condition to slab's stability is obtained by comparing slab vibration in the different downstream depth.

首次对反拱水垫塘拱圈弹性单、多底板块的振动特性进行了试验研究，提出了拱圈底板块沿流程的振动分区，给出了各振动区的界限，得到拱圈单、多底板块振动特征值沿流程及沿拱圈的分布规律，底板块振动的时域和频域特性，对不同下游水位的振动特性进行了比较，给出了对拱圈底板块的稳定最不利的条件。

However, based upon the results indicated above the heat transfer rates with certain combinations of the oscillation amplitude and Rayleigh number or Grashof number are possibly smaller than that of the stationary condition. Then the critical oscillation frequency could be regarded as a criterion of whether the heat transfer rate of the heat surface subject to a oscillation motion being larger than that of the stationary state or not .

虽然一般的观念大都认为存在振动的热表面其热传的效果会比没有振动的情形下要好，但是由研究结果得知，在不同的振幅与雷利数或葛瑞秀夫数搭配时，加入振动后的热传现象仍可能比没有振动时的热传效率差，也因此可以定义且找出临界振动频率以提供研究振动热传者之参考。

By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the reson...

通过用正弦波形模拟桥面的不平和考虑移动车辆-桥梁间的相互作用，在Euler＿Bernoulli梁理论的基础上建立了一种车桥系统的耦合振动模型·利用模态分析法和Runge＿Kutta法对模型进行数值求解，获得了车桥系统耦合振动的动态响应和共振曲线·发现车桥耦合振动的共振曲线中存在两个共振区域，一个反映主共振而另一个反映次共振·讨论了桥面不平、桥梁振型和车辆间的相互作用对系统振动的影响·数值结果表明，这些参数对系统振动的影响很大，桥面不平和振型对车桥系统耦合振动的影响不能忽略，设计车速应该远离临界车速

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。