固有频率

Firstly, this paper researched the mechanism of tubing string vibration when natural gas flows in horizontal well tubing string. Secondly, established whole tubing string undamped and damped vibration system model according as reasonable assumption data of one horizontal well. Apply finite element analysis software to calculate tubing string natural characters, simple harmonic dynamic behavior of stable gas production and nonlinear dynamic behavior. Finally, this paper carried out the safety varied frequency of gas well and the method of vibration reduction.

本文首先从理论和数值模拟研究了天然气在水平井油管柱内的流动诱发油管柱振动的机理，然后在合理假设的基础上结合某水平井数据建立了全井段油管柱无阻尼和有阻尼振动系统模型，利用有限元软件计算分析了油管柱固有特性、稳产简谐动力学响应和非线性动力学响应，针对油管柱振动规律提出了天然气安全调节频率范围和减振措施。

In the video segmentation method based on DEMD, the intrinsic mode function with the lowest frequency is discarded and a simple and effective motion compensation method is adopted. As a result, the video segmentation method is no longer sensitive to abrupt change of luminance, object motion in shots, motion and zoom in/out of cameras, so that the precision of detecting shot boundaries is improved.

基于DEMD的视频分割方法除去视频帧中反映图像内光照分布与能量的最低频率固有模态函数(intrinsic mode function，IMF)分量，并选择一种简单有效的运动补偿方法，解决了传统基于直方图方法对光照突变、镜头内物体运动和镜头运动及拉伸的敏感问题，减少了镜头边界识别的误检率，在保证召回率不受影响的前提下提高了视频分割的精确度。

However, for the anolog circuit's flaws in itself, the controllers in ultrasonic peening machine can not match the speed which they should track. Therefore, the machine is apt to disarrangement in the working state or even can not work in some cases.

但由于其模拟电路本身固有的缺点，超声冲击机内部控制电路频率跟踪系统的速度和精度以及稳定性均达不到要求，从而造成系统失谐，机器不能正常运转。

Equation (4-198) yields a first approximation for the change in the natural frequency of vibration.

方程（4－198）给出了一级近似下的固有振动频率的改变量。

Equation(4-198) yields a first approximation for the change in the natural frequency of vibration.

方程（－98）出了一级近似下的固有振动频率的改变量。

In this paper, the frequency response of the stepper motor as an electro-mechanical transformer is investigated.

针对步进电机固有的特点，对其作为电-机械转换元件的频率特性进行了深入的研究。

To solve the frequency instability of LC oscillation circuit, a fundamental frequency update algorithm is introduced.

为克服LC振荡电路频率不稳定的固有缺陷提出了基频更新算法。

On that basis, the corresponding linerized model is built, and the dynamic properties are analyzed while the configuration or end-point load is greatly changed, the predictable equation of the built-in frequency is established by virtue of perturbation method for the application of variable parameter control in that case.

利用拉格朗日方法推导了双杆柔性机械手的动力学方程，在此基础上了建立相应的线性化模型，分析柔性机械手当位形和负载发生较大改变所表现出的的动力学特性，用摄动方法建立了固有振动频率的预示表达式，以应用于位形和负载有较大改变情形的变参数控制。

Then according to the free-vibration characteristics of monorail beam, the limit safety values were discussed.

此外针对轨道梁的固有振动频率讨论其安全限值问题。

Lastly, we design a mechanical testing apparatus and tested some key components of vacuum vessel such as bellows, ports and support using photoelasticity and resistance strain gauge. From the test we have got lots of experimental data, which are very important for the design of vacuum vessel.

同时从结构动力学和疲劳设计的角度，分析了真空室的固有振型、频率及真空室在瞬时电磁力、地震载荷等动态载荷作用下的响应问题，理论给出了真空室在使役期内的疲劳用度累计损伤系数，评价了真空室的疲劳寿命情况。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。