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61.
根据多光束干涉理论,推导出等倾干涉圆环直径的计算公式,进一步得出相邻两等倾干涉圆环的直径的平方差是常数,结果与实验相符合。用Fabry Perot 干涉仪观察钠双线的等倾干涉圆环,操作比较复杂,难度较大,提出一种简捷的调节方法,所测的钠双线波长差值与标准值的误差很小。 相似文献
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把一个由GaAs光电导开关和激光腔中的普克尔盒组成的正反馈回路,用于YAG激光器中,选单纵模和调Q,获得了稳定可靠的单纵模调Q脉冲. 相似文献
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E. K. Tuseeva N. A. Mayorova V. E. Sosenkin N. F. Nikol’skaya Yu. M. Vol’fkovich A. V. Krestinin G. I. Zvereva V. A. Grinberg O. A. Khazova 《Russian Journal of Electrochemistry》2008,44(8):884-893
Comparative study of two types of single-wall carbon nanotubes and standard carbon black Vulcan XC-72 as supports for catalysts of reactions proceeding in fuel cells is carried out. The nanotubes were prepared by arc method; they differed in the degree of their purifying from amorphous carbon and metal impurities. The structure and hydrophobic-hydrophilic properties of these carbon supports are studied by etalon porosimetry. The effect of the supports’ specific surface area on the deposited catalyst particles size and specific surface area is studied. The catalysts (Pt-Ru and Pt) were deposited from aqueous solutions of their salts. Platinum was also deposited by thermal decomposition of ethoxy clusters. It is shown that in methanol oxidation reaction at the Pt-Ru catalysts the current values per unit true surface area do not depend on the support nature, provided the catalyst loading is equal and the particle size is similar. When oxygen is reduced at platinum deposited onto purified nanotubes and the carbon black Vulcan XC-72, specific kinetic currents also are close to each other. It is shown that the degree of nanotubes purification and their structure affect the kinetics of this reaction significantly. 相似文献
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为了抑制大口径光学元件中的受激Brillouin散射效应,并满足打靶过程中束匀滑的要求, 目前高能激光驱动器大都采用了正弦相位调制脉冲.然而,这类脉冲在复杂激光系统中传输时, 会出现明显的调频-调幅(FM-to-AM)效应.研究这种效应的来源,对提升激光系统的整体输出性能至关重要. 对复杂激光系统中一直被人们所忽视的平板光学元件带来的FM-to-AM效应进行了理论研究和数值模拟. 数值模拟结果表明,通过平板光学元件的次数越多调制深度越大,呈线性递增趋势,当通过次数为10次时, 调制深度高达22.2%;并且平板光学元件对各谱线的过滤也各不相同,当前端选用的中心波长为1054 nm时, 平板光学对各谱线的过滤作用非常小.提出通过改变中心波长来减小FM-to-AM效应, 这对于复杂激光系统的设计具有重要的指导意义. 相似文献
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《Current Applied Physics》2015,15(9):1047-1053
This paper presents an optimum design of a substrate-integrated cavity-type antenna for use in the terahertz frequency range. The antenna was designed with a frequency-selective surface (FSS) and a planar feeding structure that are both patterned on a high-permittivity gallium-arsenide substrate. The FSS, printed on the bottom side of the substrate, is made of a circular hole array that acts as a partially reflecting mirror. Meanwhile, the planar feeding structure, printed on the top side of the substrate, is a center-fed, open-ended slotline whose ground plane acts as a perfect reflective mirror; thus, it forms a Fabry–Perot resonator. The optimized antenna produced a maximum boresight gain of 14.3 dBi, a radiation efficiency of 62%, and side-lobe levels of −15.1 dB and −15.0 dB for the E- and H-planes, respectively, at a resonance frequency of 320 GHz. The proposed design exhibits compactness, planarity, and light weight compared with the substrate lens-coupled antenna design. 相似文献
69.
A high-finesse extrinsic Fabry–Perot interferometric sensor for the measurement of weak dc magnetic fields is demonstrated. The Fabry–Perot cavity is formed by aligning the fiber end-face and the TbDyFe rod end-face, and each end-face is coated by a mirror with a micro-lens. The length of the TbDyFe rod is changed by the variation of an applied dc magnetic field, leading a change of the Fabry–Perot cavity length. By interrogating the white-light interferometric spectrum, the wavelength of the resonant peak is tracked and the length of the Fabry–Perot cavity is obtained. The sensor exhibits a high sensitivity of 1510 nm/mT with a magnetic resolution of 25 nT. 相似文献
70.
体积全息图机制的再认识 总被引:6,自引:0,他引:6
提出了一种有关体积全息图机制的新看法,与以往的布拉格衍射模型不同,认为体积全息图由法布里-珀罗干涉仪构成,多光束干涉的优点是形成体积全息图特征的基础,基于这种新看法的计算机模拟给出了非常好的反射全息图的衍射光谱。 相似文献