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光强一定时饱和光电流随入射光频率的变化关系辨析 总被引:2,自引:0,他引:2
对光电效应实验中饱和光电流随入射光频率变化关系的几种谬误进行了辨析,给出了光强一定时饱和光电流随入射光频率变化的正确规律并作了解释。 相似文献
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Investigation on Guided-Mode Characteristics of Hollow-Core Photonic Crystal Fibre at Near-Infrared Wavelengths 下载免费PDF全文
Guided-mode characteristics of hollow-core photonic crystal fibre (HC-PCF) are experimentally and theoretically investigated. The transmission spectrum in the range from 755 to 845nm is observed and the loss is measured to be 0.12dB/m at 800nm by cut-back method. Based on the full-vector beam propagation method and the full-vector plane-wave method, the characteristics of mode field over propagation distance 1 m are simulated, and the results show that the propagation efficiency can be above 80%. Compared with the fundamental guided mode well confined in air core within shorter propagation distance, the second-order guided mode leaks into the cladding region and gradually attenuates due to larger refractive index difference. The primary loss factors in HC-PCF and the corresponding solutions are elementarily discussed. 相似文献
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TIMING OF COLLISION BETWEEN THE NORTH AND SOUTH CHINA BLOCKS——THE Sm-Nd ISOTOPIC AGE EVIDENCE 总被引:8,自引:0,他引:8
Sm-Nd isotopic ages for C-type eclogite (243.9±5.6 Ma) and mafic and ultramafic rocks(230.6±30.7 Ma and 402.6±17.4 Ma) from the Qinling-Dabieshan orogenic belt are reported.These ages suggest that at the early Triassic, the North and South China Blocks have beenunited along the Qinling-Dabieshan collision zone, and before the final collision, a se-ries of ophiolite obductions took place successively away from the continental marginduring the Paleozoic. 相似文献
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HPLC-ELSD法测定生物柴油中游离甘油含量 总被引:3,自引:0,他引:3
建立了高效液相色谱(HPLC)-蒸发光散射(ELSD)法测定生物柴油中游离甘油的方法。用水萃取生物柴油中的甘油,选用强酸型阳离子交换柱(Ultimate XB-SCX)分离甘油和杂质,流动相为乙腈-水(25:75,V:V),柱温35℃;ELSD漂移管温度30℃,载气压力360 kPa。结果表明:在7.12~307.31 mg/kg范围内,甘油峰面积和其浓度的对数具有良好的线性相关性,相关系数r为0.9929。甘油的回收率为96.3%~105.6%,RSD均小于2.0%(n=5)。最低检测限(LOD)和最低定量限(LOQ)分别为2.50 mg/kg、7.12 mg/kg。该研究为生物柴油中游离甘油的提取和检测提供了一种快速高效的方法。 相似文献
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光子晶体光纤中超连续谱的研究进展与应用 总被引:1,自引:0,他引:1
利用光子晶体光纤(photonic crystal fiber,PCF)产生超连续光谱是目前光通信光电子器件领域的一个研究热点,文章系统地介绍了石英光子晶体光纤和非石英软玻璃光子晶体光纤中产生超连续谱的理论和实验研究成果.对于石英光子晶体光纤主要介绍了实芯光子晶体光纤、空芯填充光子晶体光纤和锥形光子晶体光纤产生超连续谱的研究成果,分类介绍了其超连续谱产生的特点.对于非石英光子晶体光纤主要介绍了某些铅硅酸盐玻璃和亚碲酸盐玻璃光子晶体光纤超连续谱产生的特点.最后介绍了超连续谱的应用和发展前景. 相似文献
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Polarisation-sensitive four-wave mixing and soliton self-frequency shift effect in the highly birefringent photonic crystal fibre 下载免费PDF全文
By adjusting the polarisation state of the pump at 805 nm parallel to slow (x) and fast (y) axes of the highly birefringent photonic crystal fibre with zero dispersion wavelengths 790 nm and 750 nm, this paper demonstrates the efficient polarisation-sensitive four wave mixing involved in pump, anti-Stokes and Stokes signals and soliton self-frequency shift effects induced by the phase-matching between red-shifted solitons and blue-shifted dispersive waves. If the reduction of coupling efficiency to the circular pump laser mode or other circular fibres due to asymmetry of the core is neglected, more than 98% of the total input power is kept in a single linear polarisation. Controlled dispersion characteristic of the doublet of fundamental guided-modes results in achieving light field strongly confined in principal axes of photonic crystal fibre, and enhancing the corresponding nonlinear-optical process through the remarkable nonlinear birefringence. 相似文献
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Libove曾经证明[1],四边简支的正交异性板在双向压力下的屈曲模态沿x方向和y方向的半波数m和n这两者中必有一者为1.本文将给出m=1或n=1的条件,并确定n=1时m的取值,及m=1时n的取值.从而完全确定了四边简支正交异性板在双向压力下的屈曲模态,并给出了临界载荷的显式表达式. 相似文献
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We numerically study the propagation of 1-ps laser pulse in three tapered holey fibers (THFs).The curvature indices of the concave,linear,and convex tapers are 2.0,1.0,and 0.5,respectively.The central wavelength,located in the normal dispersion regime,is 800 nm.The nonlinear coefficient of the THFs increases from the initial 0.095 m-1· W-1 to the final 0.349 m-1·W-1.Wave breaking accompanied by oscillatory structures occurs near pulse edges,and sidelobes appear in the pulse spectrum.With the increase in propagation distance z,the pulse shape becomes broader and the pulse spectrum flattens.A concave THF is advantageous to the generation of wave breaking and enables easier achievement of super flat spectra at short lengths. 相似文献