The butterworth wavelet filter with good magnitude - frequency characteristics is adopted to process the vortex flow signal , and the fundamental frequency of signal is estimated effectively . the algorithm is implemented in a digital signal processing system based on a tms320vc5409 dsp chip , and its effectiveness is proved 采用幅频特性较好的iir型butterworth小波滤波器，处理涡街流量信号，估计基频，并在以tms320vc5409为核心的涡街流量计数字信号处理系统上实现，证明其方法的有效性。
As a result , shifting of the fundamental frequencies and redistribution of stress in the blade base possibly cause failure of the blade . a three - dimensional finite element model of a blade and its fir - tree attachments have been constructed and analyzed with taking into account of contact nonlinearity in the attachments and large deformation effect of the blade . the geometry mismatch was introduced into the finite element model by defining gaps between two contact surfaces in the attachments 分析结果表明叶根误差发生的位置对叶片弯曲振型的固有频率影响较大,对扭转振型影响较小;误差的大小对叶片各阶固有频率影响均较小,但对叶根应力分布有影响;比较发现,在计算固有频率时,将叶片在叶根处简单地处理成固支位移边界是不合理的。
A calculation method on the energy dissipation of semi - rigid steel frame is presented and it is proved that many factors , such as beam end - fixity , viscous damping , fundamental frequency of steel frame and frequency of excitation , etc . have close relationship with the energy dissipation ability of semi - rigid steel frame 5本文总结了半刚性连接框架二阶弹塑性分析方法和塑性铰分析方法，提出了半刚性连接框架耗能计算的公式。研究表明，半刚性框架耗能的大小与连接的嵌固程度、结构的阻尼、自振频率等均有很大的关系。
According to the characters of the power harmonic , a kind of self - adaptive harmonic detection method based on in - phase correlation filtering is presented , which is clear and concise in thinking . by this method the low - pass filter can be designed easily , and by using the multiresolution and self - adaptive technique the difficulties of harmonic detection with low variable fundamental frequency and no voltage reference are worked out , which contributes much to the implementation of harmonic suppression 该方法思路清晰、简洁，并能方便有源滤波器( apf )中低通滤波器设计，同时采用多分辨率和自适应滤波方法，解决了基波频率低且变化、无明显电压基准可寻的复杂供电系统谐波检测的难题，为谐波抑制的实施奠定了基础。
The cable sag and bending stiffness effects are studied on the higher natural frequencies of cable vibration . it is found that the differences of the higher adjacent frequencies go to the fundamental frequency of the taut string theory even though the cable sag or bending stiffness is included . this unique characteristic of cable vibration is used to determine the cable tension with the well - known taut string theory 2 .考虑垂度和抗弯刚度对高阶自振频率的影响，探讨了索相邻频率之差，发现索的高阶频差就是弦振动理论的基频，利用这一特性，分析了频差法测索力的精度和适用范围。
Breaking off at wuwei on the hai - jin liens , after " ti " mode joined into wuwei 330kv transformer substation , it may bring some problems , such as fundamental frequency excessive voltage , resonance excessive vohage , stability , undercurrent , reactive power compensation , etc . these problem be analyzed . it provides the schemes of design and build wuwei transformer substation and reform the transmission line of hai - jin - jia 在海金线武威开断， “ ”入武威330kv变电站后可能带来的如：工频过电压、谐振过电压、稳定水平、潜供电流、无功补偿等问题进行分析，对武威变电站的设计、建设及海金嘉线路改进提供方案。
The idea , measuring the moa resistive current only depending on current signal without using other ways , which is based on constructing the capacitive fundamental frequency current and the capacitive 3rd harmonic current , has been analyzed experimentally and theoretically . ( 3 ) . experiencing on different types of moa with this device , and then educing several new conclusions 2 )利用智能式moa泄漏电流在线监测多功能装置，对不同类型的阀片做了大量试验总结了一些新的试验结果，应用于只取电流信号分析出moa阻性电流的新想法。
The optimal model of truss structure is established , in which the cross sectional areas of bar are taken as design variables , the structure weight is taken as objective function . in the process , the reliability of structural displacement and bar stress and the fundamental frequency are taken as constraint functions . from the engineering practice , all the reliability constraints , which are implicit generally with the design variables , are equalized and transferred to the conventional explicit constraints 本文将主要考虑桁架结构的优化问题，首先建立数学模型，即以桁架的横截面积为设计变量、以重量最小为优化目标，位移、应力等可靠性及基频为约束条件；最后，从工程实际出发，对结构系统的可靠性隐形约束进行等价显化处理，使之转化为常规的横截面积优化问题。
On the basis of theoretical analysis and numerical calculations using matlab language combined with a real instance , it is indicated that the improper electrical parameter coordination caused by the abundance of power cable lines result in fundamental frequency current resonance , in addition , the countermeasures based on svc to solve the problem are put forward 文中结合某变电站异常运行状态实例，在理论分析和matlab语言数值计算的基础上，指出由于电缆的大量使用导致了该系统参数配合不当，从而诱发了基波电流谐振，并提出装设静态补偿器以防范该类谐振。
Second , through employing the 3 - d finite element model and the dual objective function inversion method developed in this paper , and taking the measured fundamental frequency of system and the structure response to a harmonic excitation at the top of structure in field as the reversion objectives , the linear material parameter inversion is performed in ansys by using ansys parameter design language ( apdl ) 第二,采用三维实体有限元模型和本文提出的双目标函数反演方法,把现场测试得到的系统基频和顶部激振下实测的结构动力响应作为反演目标,利用ansys参数设计语言( apdl ) ,在ansys软件中实现了系统材料线性参数的反演。
