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Frequency Stabilization of Pulsed Injection-Seeded OPO Based on Optical Heterodyne Technique 下载免费PDF全文
A frequency stabilizing system for a pulsed injection seeded 1550 nm optical parametric oscillator(OPO) at 20 Hz repetition rate is demonstrated.The optical heterodyne method is used to measure the frequency difference between the seed laser and the OPO output.Using the frequency difference as the error signal,a proportionalintegral controller in combination with a scanner is applied to stably match the OPO cavity length to the seed laser frequency.The root-mean-square(rms) error of the frequency discrimination method is 0.07 MHz according to a ‘frequency shifting-chopping-beat' evaluation.The frequency fluctuation of the frequency-stabilized OPO is0.29 MHz(rms),and the Allan deviation is less than 20 k Hz for averaging time of more than 3 s. 相似文献
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Off-stoichiometry indexation of BiFeO_3 thin film on silicon by Rutherford backscattering spectrometry 下载免费PDF全文
BiFeO_3 is a multiferroic material with physical properties very sensitive to its stoichiometry.BiFeO_3 thin films on silicon substrate are prepared by the sol–gel method combined with layer-by-layer annealing and final annealing schemes.X-ray diffraction and scanning electron microscopy are employed to probe the phase structures and surface morphologies.Using Rutherford backscattering spectrometry to quantify the nonstoichiometries of BiFeO_3 thin films annealed at 100?C–650?C.The results indicate that Bi and Fe cations are close to the stoichiometry of BiFeO_3,whereas the deficiency of O anions possibly plays a key role in contributing to the leakage current of 10~(-5) A/cm~2 in a wide range of applied voltage rather than the ferroelectric polarizations of BiFeO_3 thin films annealed at high temperature. 相似文献
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We propose an integral imaging system that uses three lens arrays,including two convex lens arrays and a concave lens array.Compared with the conventional integral imaging system,the proposed system can remarkably enhance the viewing angle.The maximum viewing angle can be enlarged to 48°,which is 4.8times wider than that of the conventional system.The principle of the proposed system is elucidated,and the experimental results are presented in this letter. 相似文献
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采用双水电极介质阻挡放电装置,在氩气/空气混合气体放电中,在三种边界条件下得到了一种新型的超六边形斑图.给出了超六边形斑图的傅里叶变换及其不同模强度随旋转角的变化.实验测量了超六边形斑图随空气含量和外加电压变化的相图.研究了超六边形斑图的时空动力学,发现超六边形斑图是由两套子结构嵌套而成.在四边形边界条件下,研究了放电面积的大小对斑图模式选择的影响.发现超四边形斑图的形成受边界条件影响很大,而超六边形斑图则是自组织的结果.
关键词:
介质阻挡放电
超六边形斑图
时空动力学
边界条件 相似文献
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利用乙烯常压聚合原位紫外 可见 (UV Vis)光谱技术 ,对 3个铁、钴络合物作为催化剂前体的催化剂体系进行了研究 .3个铁、钴络合物分别为 2 ,6 双 [1 (2 ,6 二甲基苯基亚胺 )乙基 ]吡啶二氯化铁 (a)、2 ,6 双 [1 (2 ,4,6 三甲基苯基亚胺 )乙基 ]吡啶二氯化铁 (b)和 2 ,6 双 [1 (2 ,6 二异丙基苯基亚胺 )乙基 ]吡啶二氯化钴(c) .实验结果表明 ,MAO对络合物催化剂前体的活化作用是一个快速过程 ;在聚合条件下分别观察到 5 6 0、6 30和 5 80nm的活性峰 ,考察了它们在聚合过程中的生长和在加入无水乙醇逐步使催化剂中毒时活性峰的消失规律 .对催化剂活性物种的结构和聚合机理进行了探讨 相似文献
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综述了具有 MWW 结构钛硅分子筛的制备方法、孔道和晶体结构的调变和修饰以及催化应用三个方面的研究进展. 与 TS-1 相比, 具有 MWW 结构钛硅分子筛的制备方法多种多样; 其孔道结构可塑性强, 通过采用层间剥离、柱撑以及分子水平硅烷化插硅扩孔技术, 可以增大和暴露孔道和外表面, 满足不同选择氧化反应的要求. 由于 MWW 结构钛硅分子筛拥有复杂而独特的孔道结构, 所以在小分子 (如直链烯烃等) 的环氧化反应, 和大分子 (环状烯烃, 二苯并噻吩等) 氧化反应中都表现出优异的催化性能. 此外, 该钛硅分子筛表现出与 TS-1 完全不同的溶剂效应, 用于烯丙基氯液相环氧化与酮类氨氧化反应主产物选择性更高. 相似文献