不同偏置电流下半导体激光器的输出模式数目

本文通过求解半导体激光器的多模速率方程组,得到了不同偏置电流下半导体激光器的输出模式数目(定义为输出谱线半宽度内的模式数目)的表达式,首次从理论上预计了在阈值电流附近半导体激光器的输出模式数目.实验结果表明,理论和实验吻合得很好.     

Er∶YCOB和Er∶Yb∶YCOB晶体的光谱分析

分别测量了 Er∶ YCOB晶体和 Er∶Yb∶YCOB晶体的室温吸收光谱。讨论了 Yb3 +离子对 Er3 +离子的敏化作用     

二元衍射光栅式偏光器件的设计

本文利用双折射晶体刻划成的二元衍射光栅的衍射偏振特性,设计了偏光器件(可分别对o光或e光起偏);偏光分束器件(包括非对称及对称偏振分束两类),并对有关参数对设计的影响进行了讨论.     

时序分析在确立铁路轨道谱中若干问题的研究

本文用时间序列分析方法对铁路轨道不平顺测量中所需测取数据个数问题以及铁路的左右两轨不平顺的功率谱分布函数的差异性问题进行了研究。这一理论与方法不仅使轨道谱的研究大大向前推进了一步,而且也可供其他领域的谱分析工作者借鉴。     

光学材料的多脉冲激光损伤研究

研究了ＺＦ２玻璃多脉冲与单脉冲激光损伤，分析了多脉冲损伤阈值与脉冲数，脉冲间隔的关系，进行了多脉冲损伤机理的分析，得出多脉冲损伤是热和缺陷累积共同作用最终促成雪崩击穿的结果，并提出了提高抗多脉冲激光损伤的方法。     

High-order harmonics in static gas target by 795-nm Ti:sapphire femtosecond laser pulses

The 5th-23sd high-order harmonics generation in rare gases in static gas target with 120-fs, 85-mJ/pulse, 10-Hz laser system was investigated. Compared with the traditional gas target, static gas target is simple to be used in experiment, and the experimental parameters can be easily controlled. The effects on high-order harmonics due to laser intensities (energy), polarization, gas densities, confocal parameter, and phase mismatch were studied in this paper.     

EFFECTIVE-MASS THEORY FOR InAs/GaAs STRAINED SUPERLATTICES

By using the recently developed exact effective-mass envelope function theory, the electronic structures of InAs/GaAs strained superlattices grown on GaAs (100) oriented substrates are studied. The electron and hole subband structures, distribution of electrons and holes along the growth direction, optical transition matrix elements, exciton states, and absorption spectra are calculated. In our calculations, the effects due to the different effective masses of electrons and holes in different materials and the strain are included. Our theoretical results are in agreement with the available experimental data.     

Salen-Mn(III)-Complex-Catalyzed Oxidations of Secondary Alcohols

IntroductionCarbonylgroupsarethemostimportantfunctionalgroupsinorganicsynthesis ,andtheirintroductionbyoxi dationchemistrystartingfromalcoholsisaprocessofmajorimportance .1Earlyprotocolsforthistransformationreliedontheuseofstoichiometricoxidantssuchaschromium(VI)reagentsorMnO2 .2 Withthegoalofimprovingsyn theticefficiencyandavoidingpotentialenvironmentalhaz ards ,prominentsuccessinthisdirectionhasbeenrecentlyachievedbyutilizingmolecularoxygenwithanassistanceofpotenttransitionmetalcompounds.3…     

铜(Ⅰ)盐催化形成C-O键合成二芳基醚的研究

在天然产物,药物及其它化工产品中二芳醚结构普遍存在,一些简单的二芳醚天然化合物还具有特殊的生理活性,但二芳醚结构的合成并不是一件容易的任务[1].尽管已有一些合成方法可以得到二芳醚,如Ullmann法,对于苛刻条件下(高温)不敏感的分子是常用的合成方法,但它通常需要计量的铜粉或铜盐,而且副反应较多原子经济性较低[2].值得注意的是近几年来利用过渡金属催化的交叉偶联反应已成为碳一氧原子键形成的重要研究方法,如Buch-wald等[3]利用钯催化剂在较为温和的条件可以得到较高产率的二芳醚,但不足之处是需要一些结构较为复杂的膦配体.近两年来,在该C-O交叉偶联反应中铜催化剂重新受到重视,我们也试图利用简单的合成方法得到二芳醚类化合物.本文报道了铜催化剂在较为温和的条件下可以得到二芳醚化合物的研究.     

纤维状硬脂酸银的合成及其表征

A new type of fibrous silver stearate (AgSt) was synthesized using double-jet method with KOH as pH regulator in water solution system. The structure, morphology and phase transiton behavior of the fibrous AgSt were characterized by FTIR, SEM, XRD and TG-DTA. SEM images showed that the diameter of the fibrous AgSt was about 150 nm and the length was 5～8 μm. XRD data indicated its layered structure and TG-DTA showed its high themal stability. In addition, the possible growth mechanism of the fibrous AgSt is also discussed.