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31.
Analysis of the Coaxial Ridge-Loaded Helical Groove Waveguide 总被引:1,自引:0,他引:1
Yonghai Lan Wenxiang Wang Yubin Gong 《International Journal of Infrared and Millimeter Waves》2002,23(3):425-434
The coaxial ridge-loaded helical groove waveguide is proposed in this paper. As an all-metal slow-wave circuit, it has advantages of good heat dissipation and great size, and thus is suitable for use of millimeter TWT. By means of field theory, the expressions of the dispersion equation and the coupling impedance of the coaxial ridge-loaded helical groove waveguide are obtained. The influence of various circuit dimensions on the dispersion relation and the coupling impedance is investigated by the results of numerical computation. 相似文献
32.
33.
Meihua Lu H. Gong T. Song Jian-Ping Wang Hong-Wei Zhang T.J. Zhou 《Journal of magnetism and magnetic materials》2006
We present a simple way to synthesize FePt and ZnO (wide-band-gap semiconductor) nanoparticle composites. The FePt nanoparticles were fabricated using the method reported by Sun et al. By controlling the heating rate, 3 nm FePt nanoparticles were synthesized. Well-dispersed FePt and ZnO nanoparticle composites were prepared by further adding zinc acetate and oleyl amine into the 3 nm FePt nanoparticle dispersion. By controlling the molar ratio of the FePt and zinc acetate, FePt and ZnO nanoparticle composites with different FePt particle fractions were obtained. The intensity of photo luminescence spectra of the nanoparticle composites increases very much with decreasing FePt particle fraction, whereas the peak position shifts a little. After annealing at 550 °C for half an hour, the nanoparticle composites become magnetically hard or semi-hard with coercivity much dependent on the FePt particle volume fraction. The coercivity of the composites increases with annealing temperature. The composites hold the promise of applications in new generation recording and/or optical devices. 相似文献
34.
Jiangen Huang Guiqin Zhang Yuanhe Huang Decai Fang Deqing Zhang 《Journal of magnetism and magnetic materials》2006
A one-dimensional (1D) silver (I) complex of nitronyl nitroxide with fairly strong antiferromagnetic interaction, in which the metal ions are diamagnetic, is investigated by means of the ab initio crystal orbital method based on the density functional theory. The calculated values of the magnetic coupling constant (J) are close to the experimental measured J value in the periodic system. The magneto-structural correlation reveals that the existence of an antiferromagnetic coupling pathway along nitronyl nitroxide units via silver (I) ion in this system. The spin population distribution also shows the existence of spin delocalization along the ONCNO–Ag–ONCNO, which affords a rational interpretation for the antiferromagnetic interaction mechanism. 相似文献
35.
针对磷化铟(InP)复合沟道高电子迁移率晶体管(HEMT)的特点,对常规单沟道HEMT的小信号物理模型进行了修正,提出了一种新的用于复合沟道HEMT的小信号物理模型,用商用器件模拟软件ISE(integrated systems engineering)对其进行了仿真验证,对比了实测和仿真的I-V特性及转移特性曲线,重点研究了在InGaAs/InP双层沟道中考虑量子效应后的电场和电流密度随着不同栅电压的变化趋势,研究结果表明,由于在沟道中存在量子效应,在栅下靠源端低电场区域,电流主要分布在InGaAs沟道
关键词:
高电子迁移率晶体管
复合沟道
物理模型
磷化铟 相似文献
36.
37.
采用射频磁控溅射技术在Pt/Ti/SiO2/Si(100)衬底上生长了掺镧钛酸铅(PLT)铁电薄膜.用X射线衍射技术(XRD)研究了PLT薄膜结晶性能,结果表明PLT薄膜为(111)择优取向钙钛矿相织构.使用原子力显微镜(AFM)和压电响应力显微镜(PFM)分别观察了PLT薄膜的表面形貌和对应区域的电畴结构.PFM观察显示PLT薄膜中存在90°纳米带状畴,电畴的极化为首尾相接的低能量的排列方式,带状畴的宽度为20-60nm.研究了PLT10铁电薄膜的制备条件与性能之间的关系.发现在优化条件下制备的PLT10铁电薄膜的介电常数εr为365、介电损耗tgδ为0.02,热释电系数γ为2.18×10-8C·(cm2·K)-1,可以满足制备非制冷红外探测器的需要. 相似文献
38.
对于线性型多目标半定规划问题,引进加权中心路径的概念,并利用单目标半定规划的中心路径法,提出了求解多目标半定规划问题的加权中心路径法,先得型对一个叔向量的有效解,然后在此基础上,提出了通过一次迭代得到对应一定范围内其他任意权向量的有效解的一步修正方法. 相似文献
39.
DIELECTRIC EFFECT ON THE RADIO-FREQUENCY CHARACTERISTICS OF A RECTANGULAR WAVEGUIDE GRATING TRAVELING WAVE TUBE 总被引:2,自引:0,他引:2
Zhigang Lu Yubin Gong Yanyu Wei Wenxiang Wang 《International Journal of Infrared and Millimeter Waves》2006,27(8):1095-1108
A new type of partial-dielectric-loaded rectangular waveguide grating slow-wave structure (SWS) for millimeter wave traveling
wave tube (TWT) is presented in this paper. The radio-frequency characteristics including the dispersion properties, the longitudinal
electric field distribution and the beam-wave coupling impedance of this structure are analyzed. The results show that the
dispersion of the rectangular waveguide grating circuit is weakened, the phase velocity is reduced and the position of the
maximum E
z
is basically invariant after partially filling the dielectric materials in the rectangular waveguide grating SWS. Although
the coupling impedance decreases a little, it still keeps above 40 Ω. 相似文献
40.
Strong Vector Equilibrium Problems 总被引:3,自引:0,他引:3
Gong Xunhua 《Journal of Global Optimization》2006,36(3):339-349
In this paper, the existence of the solution for strong vector equilibrium problems is studied by using the separation theorem for convex sets. The arc-wise connectedness and the closedness of the strong solution set for vector equilibrium problems are discussed; and a necessary and sufficient condition for the strong solution is obtained. 相似文献