低频

In MicroGrid if traditional synchronous generators were used as the main power support, the frequency of MicroGrid would fluctuate greatly during MicroGrid operated from isolated mode to grid-connected mode, and some distributed generations maybe were disconnected from the grid by low frequency relay.

如果选择微型燃气轮机作为微网的主要功率支撑手段，在微网从并网向孤网过渡过程中，系统频率波动较大，且部分分布式电源有可能在低频保护动作下与电网隔离，不利于微网的稳定运行；增加储能设备后，储能设备对于微网的稳定运行可发挥重要的作用。

Stochastic factors associated with generator frequency relay, u.f. load shedding and breaker tripping time, etc. are explicitly modeled. Using a Monte Carlo simulation tool, the risk of frequency-induced cascading failures is assessed.

该模型用以研究电力系统短期频率随机动态特性，考虑了机组频率保护、低频减载装置以及元件切除时间等随机因素，并基于蒙特卡罗模拟方法分别予以分析。

The influence of two parameters, frequency and pulse width ratio of wave pulse brush plating speed about, is studied on the base of experiment in this paper.

在低频范围内，通过试验研究了矩形波脉冲频率 f，脉冲宽度比 B对刷镀速度的影响规律。

The gas diffusion electrode with 1: 1 of mass ratio of acitivated carbon to MWNTs in catalyst layer shows the best electrode performance.

低频部分圆弧的直径随电极极化电位的增加而减小，表明该阻抗对应于氧的电化学还原过程。

Through the analysis of the work principle of three phases voltage resource PWM converter, set up the low and high mathematic models, deduce the restriction equations about grid voltage, grid current, modulation voltage and the DC output voltage and the calculation equations of the AC-side inductance and the DC-side capacitance. There are two control strategies are adopted: Predicted current control strategy and voltage-current two closed-loop control strategy, and give a comparison by theory and practice.

通过分析三相电压源型PWM变换器的工作原理，分别分析了低频和高频数学模型，并推导出了交流侧电压电流、调制电压、直流侧电压之间的数学约束关系以及交流侧电感和直流支撑电容参数的选取依据公式；分析对比了两种控制策略：预测电流控制和电压电流双闭环控制并加以实验验证；同时采用了负载电流前馈补偿和本文提出的一种基于专家系统的神经元新型智能PI控制器两种方法大大提高了整个系统的动态响应性能，并在仿真和实验中加以验证，这也是本文研究的重点内容之一。

For low frequency and logic measurement, any ground connection from scope ground to circuit ground is OK, the probe ground may be left open.

对于低频和逻辑测量﹐如有任何从示波器的地到电路地的连接﹐探头的地就可以不接。

A full range of products to improve the system the company leading product coverage of low-frequency electric power, signal transmission and high-frequency data transmission cable, cable cover with hot categories, energy-saving electric appliances, wire and cable auxiliary equipment.

完善齐全的产品体系公司主导产品覆盖低频电力、信号传输和高频数据传输电缆，同时涵盖伴热电缆大类、节能电热电器、电线电缆辅助设备。

The results showed that the impedances of composite electrodes continuously increased with increasing of immersion time.

结果表明，随浸泡时间的延长，复合电极体系的阻抗不断增大；在浸泡初期，复合电极体系的阻抗谱中即出现了低频扩散阻抗，认为该阻抗由金属表面钝化膜的溶解产物的传质引起。

The static, modal and harmonic analysis was performed in ANSYS; static capacitance, natural frequencies for the short circuit case and the open circuit (anti-resonance) case, dynamic resistance, frequency at half-power point, dynamic inductance and mechanical quality factor were computed via static, modal analysis and harmonic analysis.

为了加速低频超声雾化栽培喷头的设计制造进程、降低研发成本，该文提出了其阻抗的测试原理电路图，建立了阻抗分析的有限元模型，在大型通用有限元分析软件ANSYS中进行了静态分析、模态分析和谐响应分析。

Another haunted and related natural phenomenon is known as low-frequency infrasonic sound waves.

另一种与闹鬼相关的自然现象是称作次声的低频声波。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。