光纤光栅选频掺Yb3+双包层光纤激光器

利用相位掩模法 ,在D形内包层掺Yb3 双包层光纤一端直接写制出Bragg光栅 ,用作双包层光纤激光器的输出腔镜 .试验得到了线宽为 0 196nm ,波长为 10 5 8 2nm ,最高输出功率为 5 70mW的稳定激光输出 ,解决了激光器中模式竞争造成的输出不稳定现象 .从速率方程出发 ,对激光器的输出功率与抽运功率、光栅反射率的关系以及最佳光纤长度进行了理论分析 ,结果与实验符合很好     

Nd~(3+):YAG激光的光纤传输

首先叙述了光纤传输Nd~(3+): YAG激光的优点,接着分析了不同光纤和其传输Nd~(3+): YAG激光的特点。然后通过对光纤传输系统各部分的分析与设计,结合实际,设计了光纤耦合机构。最后,对来自于工件反射光问题提出了解决方案。     

Mean value in invexity analysis

In this paper, a generalization of the mean value theorem is considered in the case of functions defined on an invex set with respect to η (which is not necessarily connected).     

基于TMN的接入网网管系统模型

本文介绍了 TMN 网管系统的体系结构,进而讨论了接入网网管系统的体系结构和管理接口的有关问题。     

Disparity field and depth map coding for multiview 3D image generation

In the present paper techniques are examined for the coding of the depth map and disparity fields for stereo or multiview image communication applications. It is assumed that both the left and right channels of the multiview image sequence are coded using block- or object-based methods. A dynamic programming algorithm is used to estimate a disparity field between each stereo image pair. Depth is then estimated and occlusions are optionally detected, based on the estimated disparity fields. Spatial interpolation techniques are examined based on the disparity/depth information and the detection of occluded regions using either stereoscopic or trinocular camera configurations. It is seen that the presence of a third camera at the transmitter site improves the estimation of disparities, the detection of occlusions and the accuracy of the resulting spatial interpolation at the receiver. Various disparity field and depth map coding techniques are then proposed and evaluated, with emphasis given to the quality of the resulting intermediate images at the receiver site. Block-based and wireframe modeling techniques are examined for the coding of isolated depth or disparity map information. Further, 2D and 3D motion compensation techniques are evaluated for the coding of sequences of depth or disparity maps. The motion fields needed may be available as a byproduct of block-based or object-based coding of the intensity images. Experimental results are given for the evaluation of the performance of the proposed coding and spatial interpolation methods.     

Resolution of Secondary α-Ketoalcohols Catalyzed by Lipase and Inversion of Stereochemistry

Several α-ketoalcohols of synthetic value were resolved using lipase as a catalyst. Lipoprotein lipase (LPL) provided the best rate of hydrolysis and kinetic differentiation. One of these optically pure α-ketoalcohol was converted to (5)-ibuprofen in good optical purity. The stereospecific inversion of (R)-alcohol to (S)-alcohol is described.     

大功率CO_2激光器非平衡态合成WO_3／Fe_2O_3新型陶瓷催化剂──Ⅱ．WO_3／Fe_2O_3烯烃歧化反应催化剂的催化活性

用大功率ＣＯ２激光器熔制ＷＯ３／Ｆｅ２Ｏ３新型烯烃歧化反应催化剂。考查了催化剂组成、激光功率及熔炼时间与丙烯歧化反应催化活性之间的关系。     

叶栅全三维粘性反问题的数值解

本文发展了一种解叶栅全三维粘性反问题的新的数值方法.基于非正交曲线坐标与相应的非正交速度分量下完全守恒型的Navier－Stokes方程,全三维反问题规定叶片表面的无量纲压力分布反求叶型。计算中叶片表面的边界条件采用一种特殊的方式来处理，即一方面强加给定的压力分布条件,另方面叶面的几何位置在迭代过程中又是可移动的，其移动速度将与Navier—Stokes方程在当地的解联系起来，从而形成一种解定常问题的新的不定常过程.试算证明了本文方法的可行性。     

The epitaxial growth of gaas using alkylarsine: Part 2. molecular orbital calculation

Semi-empirical molecular orbital calculations were carried out for the compounds (C₂H₅)₃As, (C₂H₅)₃Ga and RAsH₂ (R = C₂H₅, i-C₃H₇, i-C₄H₉, and t-C₄H₉) by using the CNDO/2-U program, and their capability of β-elimination reaction is compared on the basis of the torsion energy to the transition state, electrostatic interactions and orbital overlapping between the central atom and the β-hydrogen, and bond order of the metal-carbon, and carbon-hydrogen bond. In the comparison of (C₂H₅)₃As with (C₂H₅)₃Ga, we found that the β-elimination of (C₂H₅)₃As could hardly be expected to take place in the thermal decomposition. The capability of β-elimination would be smaller in C₂H₅AsH₂ than that in (C₂H₅)₃As. Moreover when the ethyl group is replaced by a t-butyl group in RAsH₂, the β-elimination reaction appears to become more difficult and a large possibility for a radical process is suggested.     

硼酸铝钕(NAB)晶体光学均匀性的测量

NAB晶体是一种综合性能较好的新型激光工作物质,有希望做成高效的小型固体激光器。本文介绍一种测量这种晶体光学均匀性的方法。 一般都采用在干涉仪上观测干涉图样来判定激光棒的光学均匀性。NAB晶体的吸收光谱曲线显示出其在可见光光谱区内有多个吸收峰。我们注意到:通常用做激光干涉仪光源的He-Ne激光器发射的632.8nm谱线正位于NAB晶体的一个吸收峰,并用输出约为45mW