Nd:YAG纳米粉体的制备和光谱性质

采用共沉淀方法，以碳酸氢铵（NthHC03）为沉淀剂制备得到Nd：YAG前驱物，将其在不同的温度下煅烧并采用红外光谱（FT-IR）、X射线衍射（XRD）、透射电镜（TEM）、荧光光谱分析等技术对样品进行了表征。在900～1000℃下煅烧前驱物，出现YAP和YAM中间相并对共沉淀法中间相出现的原因进行了分析；获得纯YAG晶相的煅烧温度为1100℃，晶粒粒度分布约为40～80nm，具有良好的分散性。光谱研究表明Nd：YAG纳米粉体的发光性能良好，其红外光谱及荧光光谱与单晶无明显的差异。     

Optical properties and structures of silver thin films deposited by magnetron sputtering with different thicknesses

A series of thin Ag films with different thicknesses grown under identical conditions are analyzed by means of spectrophotometer. From these measurements the values of refractive index and extinction coefficient are calculated. The films are deposited onto BK7 glass substrates by direct current (DC) magnetron sputtering. It is found that the optical properties of the Ag films can be affected by films thickness.Below critical thickness of 17 nm, which is the thickness at which Ag films form continuous films, the optical properties and constants vary significantly with thickness increasing and then tend to a stable value up to about 40 nm. At the same time, X-ray diffraction measurement is carried out to examine the microstructure evolution of Ag films as a function of films thickness. The relation between optical properties and microstructure is discussed.     

沸点升高法测化合物的相对分子量

介绍改进后的一种利用沸点升高法测化合物的相对分子质量的实验方法：以乙醇为溶剂、相对分子质量已知的尿素作为样品，测定沸点升高常数和苯甲酸的相对分子质量．所需设备简单、测量精度符合物理化学实验教学的要求．     

长寿命导H^＋全固态电致变色器件的研究

研究了导Ｈ＾＋离子全固态电致变色器件性能退化摧在机制，发现有两个因素导致器件性能退化，在器件褪色过程中，存在于ＷＯ３薄膜中的水份将导致ＯＨ＾－在ＷＯ３中积累而在其中产生碱性环境，ＷＯ３溶于碱性环境而生成钨酸盐，在较高电压作用下Ｈ２Ｏ电解释放出气体Ｈ２和Ｏ２而使膜层剥落，通过改进器件结构和改善制备工艺条件，获得了光学密度高达０．５，着色／漂白（Ｃｏｌｏｒ／Ｂｌｅａｃｈ）循环次数高达１０＾６以上的性能     

Annealing effects on structure and laser-induced damage threshold of Ta2O5/SiO2 dielectric mirrors

The effects of annealing on structure and laser-induced damage threshold (LIDT) of Ta₂O₅/SiO₂ dielectric mirrors were investigated. Ta₂O₅/SiO₂ multilayer was prepared by ion beam sputtering (IBS), then annealed in air under the temperature from 100 to 400 °C. Microstructure of the samples was characterized by X-ray diffraction (XRD). Absorption of the multilayer was measured by surface thermal lensing (STL) technique. The laser-induced damage threshold was assessed using 1064 nm free pulsed laser at a pulse length of 220 μs.

It was found that the center wavelength shifted to long wavelength gradually as the annealing temperature increased, and kept its non-crystalline structure even after annealing. The absorbance of the reflectors decreased after annealing. A remarkable increase of the laser-induced damage threshold was found when the annealing temperature was above 250 °C.     

Kuramoto-Sivashinsky与Karda-Parisi-Zhang模型中生长界面分形特性研究

在（2＋1）维情况下，利用数值模拟研究了Kuramoto-Sivashinsky (K-S)与Karda-Parisi-Z hang (KPZ)模型所决定的非平衡态界面生长演化过程.结果表明，KPZ与K-S模型都表现出明 显的时间和空间标度特性.相对于KPZ模型而言，K-S模型所对应的表面具有更明显的颗粒特 征，当生长时间较长时，生长界面呈现蜂窝状结构.通过数值相关分析得到了生长界面的粗 糙度指数、生长指数和动态标度指数等参数.从两种模型对应的表面形貌特征和表面参数来 看，在(2+1)维情况下，KPZ与K-S模型所决定的表面具有完全不同的动态标度行为，属于不 同的两类物理模型. 关键词： Kuramoto-Sivashinsky (K-S)模型 Karda-Parisi-Zhang(KPZ)模型 分形 数值模拟     

多媒体网络教学改革研究

从教育发展史、信息时代的特点、多媒体教学特征三个方面,论述了多媒体教学的意义和特征,通过对发展多媒体网络教学所面临的机遇与挑战的剖析,认为只有与时俱进,迎接挑战,才是加快多媒体教学发展步伐的必由之路.     

量子引力的曲率两点真空相关

以平坦的Minkowski时空为背景，得到了任意坐标系和谐和坐标系中，n维GR引力和高导数引力的引力子自由传播子，求得了四种可能的曲率两点真空相关函数的首项.用微扰计算证明了曲率的两点真空相关函数在GR引力中为零，而在高导数引力中不为零.讨论了高导数引力与GR的引力子传播子、曲率相关函数的关系. 关键词： GR 高导数引力 引力子自由传播子 曲率真空相关函数 平移传播子     

Effects of shaded facets on the performance of metal-coated etched diffraction grating demultiplexer

A finite-difference time-domain (FDTD) method combined with a periodic boundary condition is used to analyze the diffraction efficiency of an etched diffraction grating (EDG) demultiplexer coated with a metallic film at the backside. The numerical results show that the diffraction loss is mainly due to the scattering effect of shaded facets of a metal-coated grating at both the polarizations. However, the same shaded facets can produce a higher loss for a TM polarization than that for a TE polarization, which induces a higher polarization dependent loss (PDL) of the demultiplexer.     

TiN/TiB2异结构纳米多层膜的共格生长与力学性能

采用多靶磁控溅射法制备了一系列具有不同TiB₂调制层厚度的TiN/TiB_{2纳米多层膜.利用x射线衍射仪、高分辨电子显微镜和微力学探针研究了TiB2层厚变化对多层膜生长结构和力学性能的影响.结果表明，在fcc-TiN层(111)生长面的模板 作用下，原为非晶态的TiB2层在厚度小于2.9nm时形成hcp晶体态，并与fcc-TiN 形成共格外延生长；其界面共格关系为{111}TiN//{0001}TiB2，〈110〉TiN//〈1120〉TiB2.由于共格界面存在晶格失配 度，多层膜中形成拉、压交变的应力场，导致多层膜产生硬度和弹性模量升高的超硬效应， 最高硬度和弹性模量分别达到46.9GPa和465GPa.继续增加TiB2层的厚度，TiB2形成非晶态并破坏了与TiN层的共格外延生长，多层膜形成非晶TiN层和非晶TiB< sub>2层交替的调制结构，其硬度和弹性模量相应降低. 关键词： 2}纳米多层膜')" href="#">TiN/TiB₂纳米多层膜 共格生长 晶体化 力学性能