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211.
In this paper, we present a spatial perturbation method to control the optical patterns in semiconductor microresonators in the far‐field configuration. We propose a fast all‐optical switch which operates at a low light level. The switching beam controls the behavior of output beams with strong intensities. The method has been applied successfully to different optical patterns such as rolls, squares, and hexagons. 相似文献
212.
阐述了MOSFET产品的应用前景,说明了其封装工艺流程及注意事项,通过对MOSFET电路常见失效现象的分析验证,探讨MOSFET产品的失效机理及其影响,对相应的失效现象制定合理的失效分析方案,确保有效查找失效的具体原因,并对失效原因从设计、工艺和材料选用等方面提出改善措施。 相似文献
213.
A novel asymmetrical diarylethene with a (formyloxyethoxy)ethyl‐linked naphthalimide unit was synthesized, and its photochromic and fluorescence properties were systematically investigated in both solution and a poly(metyl methacrylate) film. The diarylethene showed significant photochromism and notable fluorescence switching properties upon irradiation with ultraviolet/visible light. Compared with the parent diarylethene, introduction of the naphthalimide moiety was effective to increase the molar absorption coefficient, the fluorescence quantum yield, and fluorescent modulation efficiency of the diarylethene. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
214.
Power dissipation characteristics of great power and super high speed semiconductor switch
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The power dissipation characteristics of pulsed power switch reversely switched dynistors (RSDs) are investigated in this paper. According to the expressions of voltage on RSD, derived from the plasma bipolar drift model and the RLC circuit equations of RSD main loop, the simulation waveforms of current and voltage on RSD are acquired through iterative calculation by using the fourth order Runge-Kutta method, then the curve of transient power on RSD versus time is obtained. The result shows that the total dissipation on RSD is trivial compared with the pulse discharge energy and the commutation dissipation can be nearly ignored compared with the quasi-static dissipation. These characteristics can make the repetitive frequency of RSD increase largely. The experimental results prove the validity of simulation calculations. The influence factors on power dissipation are discussed. The power dissipation increases with the increase of the peak current and the n-base width and with the decrease of n-base doping concentration. In order to keep a low power dissipation, it is suggested that the n-base width should be smaller than 320μm when doping concentration is 1.0×10^14cm^-3 while the doping concentration should be higher than 5.8×10^13cm^-3 when n-base width is 270μm. 相似文献
215.
研制了基于SOS的胡杨200和胡杨700脉冲功率源。给出了胡杨200和胡杨700的电路原理、组成结构和实验波形。介绍了在SOS脉冲功率源上开展的高重复频率强流电子束产生、长寿命阴极实验、绝缘介质的高重复频率击穿实验和低引导磁场无箔二极管等实验研究进展。经测试,胡杨200在2 kHz重复频率、负载阻抗200 Ω下,输出电压200 kV,脉冲宽度约35 ns,平均输出功率大于10 kW;在300 Hz条件下可连续运行。胡杨700同样为全固态脉冲功率源,其设计指标:输出电压700 kV,电流5 kA,脉冲宽度约40 ns;经初步调试在150 Ω电阻负载上单脉冲输出指标达到660 kV,4.4 kA,脉宽约70 ns。 相似文献
216.
In this article, a novel multi-channel optical switch that is composed of a Y-shaped micromirror with two symmetrically reflective
surfaces, a fixed pivot for mounting the micromirror, and a piezoelectric actuator to actuate the micromirror, is proposed.
Working principle of this novel device is that the switching displacement of the reflective beam of light can be linearly
controlled by the displacement of the piezoelectric actuator. Accordingly, the 1×N switching task can be easily achieved. To realize the proposed concept, UV-LIGA technique was implemented to fabricate the
components. Multiple-switching concept was demonstrated through experiments. Efficiency of the proposed optical switch was
investigated by computer simulations. Optical efficiency of the proposed device can be optimized if its dimensions are adequately
designed.
Gou-Jen Wang received the B.S. degree on 1981 from National Taiwan University and the M.S. and Ph.D. degrees on 1986 and 1991 from the
University of California, Los Angeles, all in Mechanical Engineering. Following graduation, he joined the Dowty Aerospace
Los Angeles as a system engineer from 1991 to 1992. Dr. Wang joined the Mechanical Engineering Department at the National
Chung-Hsing University, Taiwan on 1992 as an Associate Professor and has become a Professor on 1999. Since 2003, he has been
the Division Director of Curriculum of the Center of Nanoscience and Nanotechnology. His research interests are MEMS, Biomedical
Micro/Nano devices, Nano fabrication.
Hong-Ru Liu received the B.S. and M.S. degrees on 2002 and 2004 from the National Chung-Hsing University, both in Mechanical Engineering. 相似文献
217.
Ahmed A. Youssef 《Analog Integrated Circuits and Signal Processing》2006,46(3):193-201
This paper presents the design considerations for the noise optimization of fully integrated tuned low-noise amplifiers (LNA)
based on the four noise parameters and two-port noise theory. Specifically, this paper provides the design guidelines for
a 0.18 μm CMOS tuned LNA. These guidelines give a useful indication to the design tradeoffs associated with noise figure,
power dissipation and gate overdrive voltage for the LNA designed using this technology. As a case study, a 10 GHz LNA has
been designed using 0.18 μm CMOS technology for a wireless LAN application. The amplifier has a 2.4 dB noise figure with a
−13 dBm third-order input intercept point, while drawing 5 mW from a 1.8 V power supply. The results show that the proposed
theoretical contours of constant noise figure which relate the gate overdrive voltage and power dissipation can accurately
predict the noise performance of a 0.18 μm CMOS LNA design
Ahmed A. Youssef received the B.Sc. (Hon.) and M.Sc. degrees both in electrical engineering from Ain Shams University, Cairo, Egypt, in 1998
and 2002, respectively. Since 2003, he has been with the University of Calgary, AB, Canada, where he is currently working
toward the Ph.D. degree in RF integrated circuits and systems.
Mr. Youssef has joined the Wireless Research Center at TRLab, Alberta, Canada as a research associate in 2004. His research
interests include the analog high speed integrated circuit for the wireless LAN applications.
Mr. Youssef is the recipient of the Mobinil Telecommunication Inc. Pre-master Fellowship in 1999. He also received the Young
Scientist award at the Maastricht General Assembly of the International Union of Radio Science in 2002 and an Honorable Mention
at 2003 in the Symposium of the Microelectronics Research & Development in Canada, Montreal. Mr. Youssef received the Gordon
Lewis Hedberg Doctoral Scholarship in 2005. 相似文献
218.
通过将衬底和栅极连接在一起实现了MOSFET的动态阈值,DTMOS与标准的MOSFET相比具有更高的迁移率,在栅极电压升高时DTMOS阈值电压会随之降低,从而获得了比标准的MOSFET大的电流驱动能力。DTMOS是实现低电压、低功耗的一种有效手段。 相似文献
219.
灵巧功率集成电路中功率MOSFET电流感知方法的研究 总被引:1,自引:0,他引:1
功率器件的过流保护是提高灵巧功率集成电路可靠性的关键,采用不同的电流检测方法会有不同的误差。通过对功率MOSFET的电流检测技术的研究,对比分析了几种常用的电流感知方法,重点阐述了应用在灵巧功率集成电路中感知高压功率器件电流的SenseFET结构的工作原理,并分析了影响电流检测准确度的误差源。可以为设计高性能的电流检测过程提供参考。 相似文献
220.