查询词典 difference frequency

We put forward a kind of filter frequency selective constructing rule which is based on correlation of filter"s frequency response integration,and took a prime sequence as Gabor filter bank"s wavelengths.As a result,we realized a novel effective scale-adaptive algorithm,which could effectively achieve high accuracy and wide disparity range.

我们针对多尺度滤波器的构造问题提出了一种基于频率响应积分面积相关的选择规则，并采用质数序列作为Gabor滤波器组的波长，实现了一种新颖高效的尺度自适应算法，不仅能够鲁棒地得到精确的视差估计，且能预测很大的视差范围，而且具有很高的计算效率。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

In order to obtain good results, we choose proper frequency range in terms of practical signals' frequency spectrum.

为了得到较好的估计结果，要根据具体信号的频谱来决定频率范围的选择。

Locking laser source to a proper frequency standard can obviously improve the laser's frequency stability.

将激光器锁定到合适的参考频率标准上，可以有效地改善激光器的频率稳定性。

Check your radio frequency with the proper operating frequency of the area or country.

请您确认您所在地区对於频率规定之相关法规，来选用适当的频率，避免与其他同好使用相同频率造成失控事件。

The maximum temperature moves to corner with the increase of frequency and proper frequency should be selected for different heating technology.

矩形板坯感应加热过程较为复杂，应根据不同工艺要求选择合适的工作频率。

It is favorable on the increase of leaf chlorophyll content,accumulation of day matter and WUE of cucumber under the proper irrigation frequency under drip irrigation manner and irrigation frequency six day.

适宜的灌溉频率也即是在滴灌条件下灌溉频率为6天对于增加叶片的叶绿素含量、干物质积累和水分利用率是有利的。

Companies such as stirring a net in April , 2008, giving degree , light preferential treatment summoning the matchmaker , joyful frequency of Pule becomes the people video frequency company of camp , license plate period of validity having no way with "the program licence spreading seeing and hearing to the information network" the first batches being 3 years.

2008年4月，激动网、优度、光线传媒、普乐欢频等公司成为第一批拿到《信息网络传播视听节目许可证》的民营视频公司，牌照有效期为三年。

Experiments show that the micromechanical tunable resonator has a resonant frequency of 4.8 kHz and a Q-factor of 500, and the tunable-range of resonant frequency is about 6.8% at the tuning voltage of 0-25 V.

梳状式可调变频率微共振器的Q值可达500，共振器共振频率约为4.8kHz，调变电压在0-25V时，可调变率达6.8%。

In the work, employing a function with four undetermined parameters to model the source wavelet, an analytical relation between Q-factor and envelope peak instantaneous frequency is derived from the theory of one-way waves propagating in an anelastic medium; at the same time, a method for extracting instantaneous frequency in wavelet domain is developed for improving the precision and anti-noise performance of IF estimation, and based on these, a method called EPIF in wavelet domain is proposed for estimating Q-factor of VSP data.

本文采用一个具有4个待定参数的函数去逼近震源子波，利用黏弹介质中单程波传播理论推导出了地震子波包络峰值处瞬时频率和品质因子之间的解析关系；同时，为提高瞬时频率的估计精度和抗噪性能，在小波域中发展了一种计算瞬时频率的方法，并在此基础上提出了估算VSP资料Q值的方法，简称小波域包络峰值处瞬时频率法。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。