查询词典 high frequency

The high efficiency transistor development causes the frequency changer the construction cost more and more to be also low, from the cost and the performance considered selects PLC to the frequency changer control realization frequency conversion velocity modulation.

大功率晶体管的开发使变频器的造价也越来越低，从成本和性能考虑选用PLC对变频器控制实现变频调速。

In this system,the VVVF(variable voltage variable frequency) control method based on magnetic flux trajectory is applied.In the system,it is the target for the magnetic flux linkage polygon to be greatly approximate to the ideal magnetic flux circle.Considering such limitations as the low speed torque ripple,high speed real time and the working frequency of switching element,through the subsection synchronization control method by applying different numbers of magnetic flux linkage polygon for different frequency range,the perfect precision specifications for speed can be obtained.

系统采用基于磁通轨迹法的他控式变频调速方案，以磁链多边形尽量逼近理想磁通圆为目标，并考虑低速转矩脉动、高速实时性和开关元件的工作频率限制等约束条件，通过采用分段同步控制方式，在不同的频段采用不同的磁链多边形边数，使系统获得了优异的转速精度指标。

For this reason, an optimal automatic timing control algorithm is proposed, that can restrain the switching frequency in a certain range to achieve the purpose of high efficiency and energy conservation. Taking such factors as inductive reactance at AC side, switching frequency, harmonic distortion rate and switching loss as well as the interaction among them into consideration, the formulas for inductive reactance and switching frequency are given; then by use of digital signal processor TMS320F2812, a prototype based on the proposed algorithm is implemented, and using this prototype the effectiveness and practicality of the proposed method are verified by experimental research and simulation.

文章提出了自动定时控制的优化算法，将开关频率限定在一定范围内，以达到高效节能的目的；综合考虑交流侧感抗、开关频率、谐波畸变率和开关损耗等指标，提出了主电路电感参数和开关频率的选择公式，并采用TMS320F2812数字信号处理器构造了试验样机，进行仿真和试验研究，其结果证明了该方法的有效性和实用性。

The frequency divider with an inverting unit and a plurality of switch inverters in series makes the two inphase selectively turned on synchronously and turned off synchronously, thereby the frequency divider, with low phase noise, can tolerate a high frequency clock.

本发明提供的分频器，通过反相单元及串联的多个切换反相器的运作，使每一切换反相器的同相开关可以选择性地同步开启或同步关闭，以使得具有低相位噪声的分频器可处理高频时钟。

On the basis of Raman and FTIR spectra research on melt structure and water solubility mechanism in albite glasses, we can make the following conclusions:(1) Higher pressure (1bar-2. 0GPa) can lead to below frequency region (50-650cm〓) shift to higher frequency and become narrower, and result in high frequency region (850-1300cm〓) move to lower wave number and become narrower at the same time. These are consistent with the decrease of average T-O-T angle and distribution scope of bond angles (0). In addition, the intensity of 580cm〓 band decrease with increase of pressure and the changes are obvious while pressure is in the range of 0.8-1. 0GPa. And these result from the"collapse"of the planar three membered -containing rings within the glass structure.

通过对高温高压下钠长石熔体结构及水在钠长石熔体中溶解机制的Raman和FTIR光谱实验研究，可以得出以下结论：(1)随着压力升高(1bar-2.0GPa)NaAlSi〓O〓熔体玻璃Raman光谱的低频区(50-650cm〓)不断变窄并向高频方向移动，同时高频区(850-1300cm〓)不断变窄且向低频区方向移动，这表明随着压力升高T-O-T键角不断减小，并且分布范围变窄，T-O-T键角这种变化从而可使T-O键的力常数减小，导致键强减弱；另外，580cm〓谱峰强度随着压力升高不断减弱，并在0.8-1.0GPa时最为显著，这是由于在0.8-1.0GPa时包含的平面三元环结构的"垮塌"造成的。

Electronic equipment categories: two core, three core insulated wire conduction test machine, an integrated plug-line tester, polarity tester, full-featured integrated precision wire tester, analog / digital storage oscilloscope, signal generator, the standard signal source, frequency dollars, Millivoltmeter distortion device,Miriam, LCR digital electric bridge, voltage tester, insulation resistance tester, grounding resistance tester, leakage current tester, electronic load, electric parameter measuring instrument, digital power meter, parameter measuring instrument transformers, transformer automatic testing system, transformers ring than phase tester, electrical safety parameter tester, variable frequency power supply, power supply, high-frequency shielding net room, temperature and humidity table, multimeter, power meter, tachometer, anemometer, coating thickness, coating thickness, vibration measuring instrument, the Composite test machines (motors, fans, hair dryer, lamps, fruit juice machine) and so on.

二芯、三芯线材绝缘导通测试机、插头线综合测试机、极性测试仪、全功能精密线材综合测试机、模拟/数字存储示波器、信号发生器、标准信号源、频率计、毫伏表、失真仪、抖晃仪、LCR数字电桥、耐压测试仪、绝缘电阻测试仪、接地电阻测试仪、泄漏电流测试仪、电子负载、电参数测量仪、数字功率计、变压器参数测量仪、变压器自动测试系统、变压器圈数比相位测试器、电器安全参数综合测试仪、变频电源、电源供应器、高频屏蔽网房、温湿度表、万用表、功率表、转速表、风速计、涂层测厚仪、镀层测厚仪、振动测量仪、综合测试机（马达、风扇、电吹风、灯饰、果汁机）等。

The every frame image was transformed by dyadic discrete wavelet and the characteristic of wavelet transform coefficient was analyzed. Low frequency coefficients were analyzed by fast principal component method which quoted Gram-Schmidt orthonormalization procedure in fixed-point algorithm then distilled principal component and reconstructed the low frequency coefficients. To suppress image noise, the high frequency coefficients were equated to zero.

该算法对热图像序列中的每帧图像进行二进制离散小波变换，提取出低频部分的系数；对低频系数进行改进PCA分析，通过固定点算法并引入Gram-Schmidt正交化过程求解特征向量；令高频系数为零，抑制图像的噪声。

In view of it, the algorithm based on the Fast Fourier Transform techniques with quadratic interpolation in the frequency domain is mainly presented. After that,the simulation is carried on and analyse the simulation curves deeply. It ndicates that this algorithm can not only enhance the frequency resolution, but only estimated frequency has high reliability and excellent stability. And it\'s feasible.

主要介绍一种基于FFT和在频域内二次插值的频偏估计算法，之后进行仿真、深入分析仿真曲线，结果表明该算法不仅可以提高频偏估计的精度，而且频偏估计值具有很高的可靠性和良好的稳定性，该算法是可行的。

Methods:Normal frequency ventilation of high frequency jet respirometer was used to control breath continuously for 31 cases without autonomous breath,the ventilation frequency:16～20 times/min with continuous ventilation time 12～72 hours.

结果：通气1h后PaO2（15.92±2.50）kPa，PaCO2（5.90±0.76）kPa；通气24h后PaO2（14.76±3.21）kPa，PaCO2（6.11±0.84）kPa。在Ⅱ型呼吸衰竭，常频与高频通气交替应用比单用高频通气辅助呼吸，其提高血氧分压的疗效优越（P＜0.001），且可防止高碳酸血症。

A silent communications system in which nonaural carriers, in the very low or very high audio-frequency range or in the adjacent ultrasonic frequency spectrum are amplitude- or frequency-modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones, or piezoelectric transducers.

一个沉默的联系是不承载听觉，在非常低或非常高音频范围里，或在邻近的超音速的频谱中，这是广阔的-或带有期望的智能并且传播声学的频率调节或振动，为了刺激大脑内部，典型的是通过利用扬声器，耳机，或压电式换能器。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。