Optical spectroscopy of Yb/Er codoped NaY(WO4)2 crystal

Erbium and ytterbium codoped double tungstates NaY(WO₄)₂ crystals were prepared by using Czochralski (CZ) pulling method. The absorption spectra in the region 290-2000 nm have been recorded at room temperature. The Judd-Ofelt theory was applied to the measured values of absorption line strengths to evaluate the spontaneous emission probabilities and stimulated emission cross sections of Er³⁺ ions in NaY(WO₄)₂ crystals. Intensive green and red lights were measured when the sample were pumped by a 974 nm laser diode (LD), especially, the intensities of green upconversion luminescence are very strong. The mechanism of energy transfer from Yb³⁺ to Er³⁺ ions was analyzed. Energy transfer and nonradiative relaxation played an important role in the upconversion process. Photoexcited luminescence experiments are also fulfilled to help analyzing the transit processes of the energy levels.     

液晶显示器生产中的激光退火和缺陷修复

由于在大面积玻璃基底上制备由多层材料构成的高质量薄膜晶体管象元驱动阵列工艺的复杂性，使有源矩阵液晶显示器（AMLCD）的成品率低、价格高。利用激光对AMLCD进行非晶硅薄膜的退火和电路缺陷的修复，可有效的改善AMLCD的性能，提高成品率和降低成本。本文在介绍了激光对非晶硅薄膜退火和电路缺陷修复常用激光器的特性后，讨论了激光对不同类型缺陷修复的原理和过程。最后，分析比较了不同类型激光退火方法的特点。     

基于超分子结构共掺杂纳米复合薄膜的制备与荧光特性

为改善功能分了的特性,提出一种基于金属纳米粒子-偶氮染料复合物共掺杂超分子结构功能材料的设计新方法.并依照此方法制备出复合材料,观测了其显微结构,测量了其紫外-可见光吸收,研究了该超分子结构复合体系的荧光特性.实验发现,由于金属银纳米粒子的掺杂,使得超分子结构复合体系中功能分子甲基橙在溶液态体系的荧光强度增强近5倍,而在两种不同结构(共混结构和包覆结构)的薄膜态超分子结构体系中,其荧光强度分别被猝灭15%和20%.研究结果表明,复合膜中采用超分子结构完全能够改善功能分子的特性.     

Measurements of the perpendicular width of ionization-produceddouble layers

Measurements of the perpendicular (to B) double-layer widths of ionization-produced (anode) double layers are presented. These widths were determined from measurements of the double-layer charge separations. The variations of the transverse-to-B widths with plasma density and magnetic field strength are given     

电子直线加速器束流均方根发射度变化方程

本文导出了考虑外场和束流效应后束流均方根发射度平方变化方程的一般表达式,并就仅考虑外场,仅考虑空间电荷场和仅考虑尾场等三种特殊情况进行了分析。     

微波BJT超宽带低噪声放大器的设计

本文给出了一种频带覆盖达１０－１６００ＭＨｚ的微波ＢＪＴ超宽带低噪声放大器的设计方法，从微波ＢＪＴ的噪声模型出发，通过拟合５０Ω源阻抗下微波ＢＪＴ的噪声系数ＮＦ５０和Ｓ参数来提取其噪声参数，然后根据增益，噪声及驻波比要求优化设计放大器，使放大器在超宽带范围内获得平坦增益和低噪声，本文所给出的微波ＢＪＴ惨数提取及放大器优化设计方法已由实验结果所验证。     

介质加载圆柱腔的场分析

本文应用严格场匹配法解决了介质加载圆柱腔的本征问题，计算了圆柱腔在纵向部分填充介质后ＴＥ０１ｎ模和ＴＭ０１ｎ模的本征频率和本征场型的变化。特别分析了本征模式在空气段为截止模的情况。本文的分析方法亦可应用到纵向部分填充介质的传输线和其它形状的谐振腔。     

用稳态反饱和吸收法测量C_（60）的激发态吸收截面

用准连续激光实现了Ｃ６０的稳态反饱和吸收，通过实验和理论计算的拟合，确定了Ｃ６０的三重第一激发态吸收截面。