高功率

In recent years, SiC FET power transistor and GaN high electron movability power transistor represent the third generation semiconductor-wide bandgap semiconductor power devices, have advantages of high breakdown voltage, high power density, as well as high output power, high operation efficiency, high operation frequency, wide instant aneous bandwidth, operation in high temperature environment and strong ability of resisting radiation.

近年来以SiC场效应功率晶体管和GaN高电子迁移率功率晶体管为代表的第三代半导体－宽禁带半导体功率器件具有击穿电压高、功率密度高、输出功率高、工作效率高、工作频率高、瞬时带宽宽、适合在高温环境下工作和抗辐射能力强等优点。

Power to switch to a high frequency, high efficiency, high power density, high power factor, high reliability.

使开关电源达到了频率高、效率高、功率密度高、功率因素高、可靠性高。

The main content of this dissertation includes: 1. Research on the theory of ultrasonic power supply, introduce its development process. On the basis of these, fix on the scheme of medical ultrasonic low-power supply. 2. According to the principle of modularized design, divide medical ultrasonic low-power supply into four parts. They are power amplify circuit, power control circuit, frequency automatic tracking circuit and matching circuit. Separately research on their theories and design their circuits and necessary programs, especially, effectively resolve the problem tracking the supersonic vibration system with a narrow syntony frequency bandwidth and a high swing. 3. The matching experiments gain good result, and prove that medical ultrasonic low-power supply is entirely up to the mustard on intellectualization, wide band of working frequency, steady output and high efficiency.

本文工作的主要内容包括： 1、研究了超声功率电源的原理，并回顾了它的发展过程，在此基础之上确定本文医用小功率超声电源的设计方案； 2、按照模块化的设计原则，将医用小功率超声电源的设计分解为功率放大电路、功率控制电路、频率自动跟踪电路和匹配电路等四个部分，分别研究了各部分的原理，在此基础之上进行了具体的电路设计和程序设计，尤其是有效地解决了对谐振频率带宽窄振幅高的超声振动系统的频率跟踪问题； 3、通过与超声振动系统的各项配合实验，取得了很好的实验结果，验证了医用小功率超声电源完全满足智能化、工作频带宽、输出功率稳定、输出效率高的设计要求。

The main peaks of the EEG power spectra were in delta and theta frequency range. In the stage of ethanol exposure, the rats exhibited much more act of attack than the control, the alpha waves of EEG decreased, while the delta waves increased. The EEG power spectra analysis showed the delta power increased and the theta power decreased. In the stage of ethanol withdrawal, the rats showed some withdrawal behaviors such as wet dog shakes, sniffing, groomingand tonic-clonic seizures for audiogenic stimulus. Spikes and spike-slow waves were found in the EEG. In power spectra analysis, the delta power decreased while the alpha and the theta power increased, the EEG frequency band moved to the high-frequency rang. These changes were found obviously on the sixth day and disappeared on the 1 Oth day after the ethanol was removed.

本研究发现：1、对照组大鼠行为无异常，伏核EEG以α节律为主，散在出现δ和θ节律；功率主峰在δ和θ频段范围，整个过程中未发现手术对伏核EEG及脑电功率谱有影响。2、在慢性饮酒过程中，大鼠攻击性行为增加，伏核 EEG的α节律明显减少，散在出现的高幅慢活动δ波逐渐增多，功率谱分析表明δ频段功率百分比明显增加，而θ频段功率百分比明显减少，总功率减少。3、停饮后，大鼠出现湿狗样抖动、打喷嚏等撤药综合症，并且高频声音刺激能引发惊厥；伏核EEG出现棘波和棘慢综合波，并持续增多，功率谱分析显示δ频段功率百分比 5 南京医科大学硕士学位论文逐渐减少，而0和以频段功率百分比逐渐增加，总功率增加。

The agitation power consumptions in boiling systems decrease uniformly with the increase of agitation speed, whereas the relative power demand (RPD-the ratio of agitation power input of HEDT for gassed system to that for ungassed system and under the same agitation speed) can maintain at a high level for high gas loadings even when the impeller is operating with a high impeller tip speed. The gas hold-up in the boiling system is much lower than that in the cold gassed system, and the gas hold-up in boiling system increases at first and then decreases with the increase of the agitation power consumption per liquid mass P(subscript m. It implies that the boiling three-phase system has a maximum gas hold-up point. The changes of nucleation site of vapour bubble and the character of suspension of the solid particles with the rotational speed of the impeller are responsible for those behaviors mentioned.

在沸腾条件下，搅拌功率消耗随着搅拌转速的增加有所下降，但HEDT桨具有较高的载气能力，即使在高叶端线速度下，相对功率消耗仍能保持在较高的水平；沸腾体系的气含率随单位质量流体输入功率的增加表现出先增后减的规律，即存在气含率的极大值，蒸汽成核位置和固体颗粒悬浮特性随搅拌功率增加而改变是造成上述行为的主要原因；沸腾体系中的气含率远远低于常温通空气体系。

The nonlinear laser beam propagation in high power laser driver and the influence of the smallscale selffocusing and phase noise on beam quality in disk amplifier have been analyzed by a linear model.

建立了一套线性的近似分析方法，研究高功率激光驱动器中强激光传输的小尺度自聚焦效应和相位噪声对光束传输和光束质量的影响，给出了系统噪声强度、B积分值与光束近场调制对比度之间的定量关系。

Nonlinear vibration phenomena including superharmonics, subharmonics, quasi-subharmonics and chaos in metal plates excited by intensive ultrasonic pulses are studied experimentally and theoretically.

对高功率超声脉冲作用下金属板中的超谐波、次谐波、准次谐波以及混沌等非线性振动现象进行了实验和理论研究。

These high power thin film terminators exhibit excellent high frequency characteristics.

这些高功率薄膜终端表现出优异的频率特性。

Based on the bi-amping principle, each of the B300's drivers is powered by a dedicated high-power amplifier using an active, phase-optimized crossover network.

根据双路功放的原理， B300 的每个驱动器都有高功率的配有有源分频器的功放。

This paper introduces the studies of the ultra-short Thomson scattering X-ray source at the accelerator laboratory of Tsinghua University in recent years. Properties such as the photon yield,the pulse length and time jitter of the produced photon pulse were predicted theoretically from the parameters of the electron bunch and the laser pulse,and the scattering angle. Preliminary experiments were successfully carried out with a 16 MeV backward-traveling-wave accelerator and the ns-Q switched laser provided by China Academy of Engineering Physics. This paper also introduces the 1.6-cell electron gun that was fabricated on site and the experiment with high RF power including the measurement of the electron bunche parameters. Based on these,we have designed an X-ray source,which is now under construction.

介绍了清华大学加速器实验室近年来关于汤姆逊散射超短X射线源的研究工作；研究了在任意散射角度下电子束参数和激光束参数对散射光子参数的影响，给出了散射光子的参数如光子产额、脉冲长度、时间抖动等与电子束参数、激光束参数和散射角度的关系；利用实验室已有的16 MeV反波行波加速器与中国工程物理研究院激光聚变研究中心提供的ns调Q激光搭建了汤姆逊散射初步实验平台并开展了实验研究；加工了1.6-cell光阴极微波电子枪，搭建了高功率实验平台，对产生的电子束参数进行了初步测量；对汤姆逊散射超短X射线源进行了设计并开展了相关的平台建设工作，对产生的X射线脉冲参数进行了模拟。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。