查询词典 power frequency

Finally designs has the tonality control circuit the audio frequency amplification electric circuit to have very well chooses the frequency function, with pronunciation magnifying power.

最后设计出来的带有音调控制电路的音频放大电路具有很好的选频功能，和语音放大能力。

Using retriggerable monostable multivibrators to provide the trigger signal and double MOS driver to drive the LD, with a lot of experiments, emulations and comparisons, the variable frequency, pulse width and power driver circuit is designed. And the pulse frequency and width can be changed easily for its situations.

然后用电子多频振荡器提供驱动信号，用双MOS驱动器来驱动半导体激光器，通过大量的实验、仿真、分析、比较，设计出了方便可调的大功率LD的驱动电路，该电路的脉冲频率和脉冲宽度可方便调整。

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。

The numerical results show that outer scale of turbulence has great effect on G-tilt power spectrum and residual variance of tilted tracking at low frequency but almost has no effect on the high frequency.

数值计算结果表明大气湍流外尺度对G倾斜功率谱以及倾斜跟踪残余误差的低频段影响较大，而对高频段的影响可以忽略不计。

Wavelet theory is a newly time-frequency analyse method, which developed in recent years, it has A good resolving power in time domain and frequency domain.

小波变换理论是近年发展起来的一种新的时-频分析方法，它不但在时域具有良好的分辨率，而且在频域也具有极高的区分能力。

Weld line is the key part of ERW steel pipe because the impact toughness of its raw material is multiple times higher than that of seamless steel pipes. The impact energy of weld line can reach 60% of the raw material by controlling impurity content in raw material, the height and direction of the burr, mold border shape, welding leg, welding speed, heating power and frequency, welding extrusion capacity, the depth and temperature of intermediate frequency, as well as air-cooled length. Seamlessness can be realized if further optimization methods are adopted.

由于ERW钢管母材的冲击韧性数倍于无缝钢管，焊缝处的冲击韧性是ERW钢管的关键，通过控制原材料杂质含量、纵剪毛刺高度与方向、成型边部形态、焊角、焊接速度、加热功率与频率、焊接挤压量、中频退伙温度与深度、空冷段长度等工艺参数保证了焊缝的冲击功达到母材的60%以上，如进一步优化，可实现焊缝冲击功接近母材，从而实现性能无缝化。

Simultaneous heating and quenching with high power medium frequency equipment for parts of long shaft,adopting special induction coil and adjustable induction coil and self tempering ,will improve on medium frequency quenching quality of the parts and raise obviously productivity,thereby cause the enterprise to obtain fine product quality,high productivity and Low production cost.

对长轴类零件采用大功率中频机同时加热表面淬火的方法，配以专用感应圈和伸缩感应圈的应用和自回火的应用，结果表明，可提高零件中频表面淬火质量，并大大提高生产效率，从而使企业在生产中取得高产品质量，高生产效率和低生产成本的极佳效果。

Measure character: Frequency limits: CH1:dResolution of C ～ 225MHz frequency: 10 / second time-interval resolution : N/A measures speed: Can amount to 200 times measure / the second mixes in limits of the voltage on GPIB sensitivity : DC ～ 100MHz: 200MHz of ～ of 5Vac+dc 100MHz of 20mVrms ～±: 225MHz of ～ of 5Vac+dc 200MHz of 30mVrms ～±: Input of 5Vac+dc of 40mVrms ～± adjusts:(CH1 chooses) impedance, coupling: 1M Ω or 50 Ω, ac or Dc are low connect filter: 100kHz, but switch attenuation:× 1 or reference of × 10 exterior time base inputs: 1, 5, 10MHz sparks: CH1, to rising / drop the edge sparks, the percentage that uses signal n or absolutely voltage install n, setting sensitivity mixes to low, medium or tall gate start: Automatic, the hand is moved (setting gate time or resolution digit); Exterior, defer interface: Standard GP-IB(IEEE 488.1 and 488.2), take; of SCPI compatible language to say RS-232 power source only: 10 ％ of 100-120VAC ±, 50, 60 or 10 ％ of 400Hz ± 10 ％ of 220-240VAC ±, 50 or 10 ％ of 60Hz ± are suttle: 3kg dimension: 348.3mm of × of 212.6 × 88.5H

测量特征：频率规模：CH1：dc～225MHz 频率分辨率：10位/秒时候距离分辨率：N/A 测量速度：可达200次测量/秒在GPIB上电压规模和灵敏度： DC～100MHz： 20mVrms～±5Vac+dc 100MHz～200MHz：30mVrms～±5Vac+dc 200MHz～225MHz：40mVrms～±5Vac+dc 输入调节：(CH1选择)阻抗，耦合： 1MΩ或50Ω，ac或dc 低通滤波器： 100kHz，可切换衰减：×1或×10 外部时基参考输入： 1，5，10MHz 触发： CH1，对回升/回升沿触发，用信号电平的百分数或相对电压设置电平，设置灵敏度至低、中或高闸门和启动：主动，手动(设置闸门时候或分辨率位数)；外部，延迟接口：尺度GP-IB(IEEE 488.1和488.2)，带SCPI兼容说话；只讲RS-232 电源：100-120VAC±10％，50，60或400Hz±10％ 220-240VAC±10％，50或60Hz±10％净重：3kg 尺寸：212.6×88.5×348.3mm

The composition voltage, the electric current double closed loop voltage-stabilized source, used the integrated phase shifting crystal thyratron module to do for the electrical energy transformation component, in detail has calculated the rectification main circuit main component parameter; In the pulse-duration modulation part, used the special-purpose integrated circuit to realize the frequency modulation to adjust the pressure, did take IGBT as the power transformation component, realized the output voltage frequency modulation to adjust the pressure, and has calculated the related parameter.

在调压稳压电压源设计中采用二阶工程设计法设计了电压和电流调节器，组成电压、电流双闭环稳压电源，采用集成移相晶闸管模块做为电能变换器件，详细计算了整流主电路主要器件的参数；在脉宽调制部分，采用专用集成电路实现了调频调压，以 IGBT 做为功率变换器件，实现了输出电压的调频调压，并计算了有关参数。

This paper presents a low voltage, low power RF/analog front-end circuit for passive ultra high frequency radio frequency identification tags.

提出了一种适用于无源超高频射频识别标签的低电压低功耗射频／模拟前端电路。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。