共查询到20条相似文献,搜索用时 31 毫秒
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Bishnu P. Pal Sonali Dasgupta M.R.Shenoy Alexej Sysoliatin 《光电子快报》2006,2(5):342-344
Nonlinear optical effects such as self-phase modula-tion,four-wave mixing,cross-phase modulation,sti mula-ted Raman scattering,together with appropriate tempo-ral dispersion profileinan optical fiber couldsignificant-ly broaden ( >100 nm) the spectrumof a… 相似文献
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The radiation pattern of an open-ended co-axial line excited in the TEM mode in a plasma column having a central conductor along the axis is studied. The field distribution at the open-end cross-section of the co-axial line is assumed to be equivalent to the vector sum of magnetic current rings of various radii, ranging from the outer radius of the inner conductor to the inner radius of the outer conductor of the co-axial line at the open end. The radiation field is obtained as a vector sum of field components duo to individual rings of magnetic current. This type of configuration gives rise to a veil-enhanced radiation peak near and before the critical angle. The amplitude of the radiation peak depends upon the dimensions of the plasma column, the diameter of the central conductor and the inner diameter of the outer conductor of the coaxial line at the open end. Its direction can be changed by changing the plasma density. Based upon these results it is proposed to develop an electronically scannable narrow-beam plasma antenna system. 相似文献
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研究了一种基于硅悬臂梁谐振器的新型气体传感器.该传感器在敏感环境中,可同时获得敏感膜电导率和质量变化,测量被测气体分子的荷质比,具有高灵敏度和高选择性.根据这一原理,针对气体传感器的需求,设计了硅悬臂梁谐振器化学传感器结构,进行了仿真优化,并采用MEMS表面牺牲层工艺制备该器件,激光频率仪测量验证了该微型谐振梁的谐振频率. 相似文献
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Wei-Shuai Lü 《中国电子科技》2009,7(1):78-81
Functional magnetic resonance imaging (fMRI) is a new tool for brain-computer interface (BCI). This paper presents an overview to fMRI-BCI. Our attention is mainly put on the methods of signal acquisition, signal preprocessing, and signal analysis of basic fMRI-BCI structure. The available softwares and the applications of fMRI-BCI are briefly introduced. At last, we suggest focusing on some technologies to make fMRI-BCI more perfect. 相似文献
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CHEN Xiu-bo LIU Xin-yuan WEN Qiao-yan School of Science Beijing University of Posts Telecommunications Beijing China State Key Laboratory of Integrated Services Network Xidian University Xi’an China ZHU Fu-chen National Laboratory for Modern Communications Chengdu China 《中国邮电高校学报(英文版)》2006,13(4):39-42
1 Introduction In the burgeoning field of quantum information theory, people have found many remarkable applications of quantum mechanics [1?4]. One of the striking nontrivial techniques in quantum information is the existence of the procedure called quan… 相似文献
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A 72 mW highly integrated dual-channel multimode GNSS(global navigation satellite system) receiver with aΣ△fractional-N synthesizer which covers GPS L1 and the Compass B1/B2/B3 band is presented.This chip was fabricated in a TSMC CMOS 0.18μm process and packaged in a 48-pin 3×3 mm~2 land grid array chip scale package.This work achieves NF≤5.3 dB without an external LNA,channel gain = 105 dB for channel one (Compass B2 and B3 band),and channel gain = 110 dB for channel two(GPS L1 and Compass B1 band).Image rejection(IMRR) = 36 dB,phase noise is -115.9 dBc @ 1 MHz and -108.9 dBc @ 1 MHz offset from the carrier for the two channels separately.At the low power consumption,multibands of GNSS are compatible in one chip, which is easy for consumers to use,when two different navigation signals are received simultaneously. 相似文献
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提出了一种符合IEEE802.11a无线局域网的5GHz直下变频接收机解决直流漂移的方法. 该方法利用双平衡混频器输出端的模拟反馈环路消除直流漂移. 该混频器经过测试,在5.15GHz频率下具有9.5dB的转换增益,13.5dB的噪声系数和7.6dBm的三阶交调,在3.3V电源电压条件下67mW的功耗,以及1.73mV的直流漂移,并能使直流漂移减少76%. 该方案及整个直下变频的WLAN接收机已经采用0.35μm SiGe BiCMOS工艺流片并测试. 相似文献
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V. E. Lyubchenko V. I. Kalinin V. D. Kotov D. V. Lyubchenko D. E. Radchenko S. A. Telegin E. O. Yunevich 《Journal of Communications Technology and Electronics》2018,63(9):1059-1063
The design of a microwave oscillator based on a microstrip log-periodic antenna integrated with a field effect transistor and a waveguide built in a dielectric substrate has been developed and analyzed. The waveguide geometry provides the possibility of propagation and radiation at both the fundamental frequency of the log-periodic antenna and harmonics. Computer simulation of the oscillator design in a frequency range near resonance frequencies of the log-periodic antenna is conducted. The possibility of summation of powers of several antenna–oscillators arranged ias a linear phased array is investigated. 相似文献
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