高重复频率激光脉冲作用下KTP晶体中的灰迹

采用波长为1 064 nm/532 nm、脉宽6 ns(FWHM)的高重复频率调Q激光,研究了磷酸氧钛钾(KTP)晶体中灰迹的产生机理,以及色心密度对灰迹的影响。晶体透过率表征了色心密度,根据透过率与色心密度的关系以及色心密度对灰迹产生的决定作用,定义临界灰迹密度,当晶体透过率高于此值时可安全运行,而低于此值时,为避免晶体发生灾难性损伤应立即停止运行。实验结果表明:灰迹不仅大量吸收紫外及可见光能量,而且大量吸收近红外波段能量,这为灰迹的在线监测提供了一种监测方法。     

铒纤长度对单程掺铒光源输出特性的影响

 分析铒纤长度对掺铒光源输出特性的影响对于光源的优化设计有重要意义。实验分析了铒纤长度对单程前向和后向掺铒光纤光源(SFS)输出特性的影响。分析了铒纤长度与单程SFS输出光功率的关系,以及铒纤长度对单程SFS输出光谱宽度及中心波长的影响。找到了最佳铒纤长度的范围,对单程掺铒光纤光源的器件选择及性能优化有重要的参考价值。     

Synthesis, Characterization and Luminescence of Lanthanide Chloride Complexes with N,N,N'''',N''''-Tetra[(2-benzimidazolyl) methyl]-1,2-Ethanediamine

Imidazole groups play an important role in the coordination chemistry of the metal ions in many biological systems1. Earlier work has established its suitability for formations of binuclear copper1, iron2 and manganese3 complexes. Reaction of EDTB with Cu(H2O)6(BF4)2 in absolute ethanol has given a six-coordinate complex of [Cu(EDTB)](BF4)(BF3?O(C2H5)2)H2O4. Rare earth ions have similar physical and chemical properties with Ca2+ and Mg2+ which are important in biological systems. Wan…     

球体上滚问题分析

研究球体在不平行双直线型导轨上的上滚实验问题,包括上滚原因、条件和如何获得最佳的演示效果,并给出一个关于椭圆的几何命题.     

CENTERS OF SOME CUBIC SYSTEMS

1 IntroductionWe consider the systemwhere x, y, at) bj are compIex variables, S = {l. = (p., q.) lPm qm 2 1, m =l ? l} is a subset of { -- 1 U N} x N, and N is the set of non--negative integers (wewill write apq, b,, instead of a(P,q)! 5(,,,)). Let E(a, 5) ag {(a1, ? al2 5'' 5 ait 5 b,, t..' 5 5j,)} = Czl be the space of coefficients of system (1) (here and beIow wefix the order tk = (pk, qk) and jk = (qk, pk)), C[ai, ) ai2,'' 5 azl, b,,,'' 5 5j,l agC[a, 6l be the ring of poIynomiaI…     

Solving variational inequalities defined on a domain with infinitely many linear constraints

We study a variational inequality problem whose domain is defined by infinitely many linear inequalities. A discretization method and an analytic center based inexact cutting plane method are proposed. Under proper assumptions, the convergence results for both methods are given. We also provide numerical examples to illustrate the proposed methods. The work of S. Wu was partially supported by the National Science Council, Taiwan, ROC (Grant No. 19731001). S.-C. Fang’s research has been supported by the US Army Research Office (Grant No. W911NF-04-D-0003) and National Science Foundation (Grant No. DMI-0553310).     

V3+∶YAG晶体的生长、色心与光谱性能研究

采用石墨电阻加热的温梯法生长了V∶YAG晶体，晶体的不同部位呈现两种不同的颜色：浅绿色和黄褐色.通过对比分析不同颜色V∶YAG晶体的室温吸收光谱，推断出石墨发热体高温下扩散出来的C可以起到还原作用，提高晶体中V³⁺_tetra离子的浓度，同时诱导了F心的形成.在1300℃下，对不同颜色的V∶YAG晶体进行真空退火处理，发现处于八面体格位中的V³⁺离子在热激发作用下与近邻的四面体格位Al³⁺离子存在置换反应，由此产生一定浓度的四面体格位V³⁺离子.同时，F心在退火过程中被完全消除，释放出来的自由电子被高价态的V离子俘获，可以进一步提高晶体中四面体格位V³⁺离子的浓度. 关键词： V∶YAG晶体 四面体格位 碳还原 真空退火 F心     

Ti: LiAlO2新型晶体的结构分析

通过研究提拉法生长的掺杂Ti浓度为0.2at%的LiAlO₂晶体吸收光谱，荧光光谱和红外光谱，来分析此新型晶体的结构.分析发现光谱中仅出现了四价Ti离子的196nm的特征吸收峰, 用235nm光激发得到384nm的特征发射峰；针对吸收光谱中660—820nm出现的四个弱小吸收峰提出了一个色心模型，从而解释了空气和富Li气氛处理后吸收峰消失的现象；对比纯LiAlO₂晶体的红外光谱发现，Ti的掺入仅影响了［AlO₄］键强，而［LiO_{4 关键词： 2}')" href="#">Ti: LiAlO₂ 色心 光谱