离焦散斑技术研究Kirchhoff板在动载作用期的弯曲

本文使用动态离焦散斑技术,测试板的动态弯曲获得成功。并推导了Kirchhoff板动态变形的有关分析,提出了由最大斜率确定材料常数的思想。显然,这是同离焦散斑方法所测数据直接相关的处理手法。     

激光器实用价值的评判

提出用于评价激光器产品实用价值的Q因子,它由激光器的亮度、脉冲宽度及价格确定。Q值大的激光器,开发及发展的潜力大。     

铽－甲基吲哚乙酰丙酮三元配合物发光过程研究

测定和分析了ＲＥ．Ｌ１．Ｌ２（ＲＥ＝Ｔｂ（Ⅲ）、Ｇｄ（Ⅲ），Ｌ１＝３Ｍ（３甲基吲哚－１－乙酰基丙酮），Ｌ２＝ＴＰＰＯ、Ｐｈｅｎ、Ｄｉｐｙ）三元配合物的荧光光谱、磷光光谱、磷光寿命及变温荧光光谱等．讨论了Ｔｂ（Ⅲ）与配体之间的能级匹配和Ｌ１与Ｌ２的三重态之间传能的问题，说明了影响这些三元配合物荧光效率的主要因素及其发光过程．     

Sun工作站上的一种可视编程工具

本文主要介绍Ｓｕｎ Ｏｐｅｎｗｉｎｄｏｗｓ Ｄｅｖｅｌｏｐｅｒ’ｓ Ｇｕｉｄｅ３．０．１软件的简单使用和主要特点。     

Controllable synthesis of ZnS/PMMA nanocomposite hybrids generated from functionalized ZnS quantum dots nanocrystals

We reported controllable synthesis of ZnS nanocrystal-polymer transparent hybrids by using polymethylmethacrylate (PMMA) as a polymer matrix. In a typical run, the appropriate amounts of zinc chloride (ZnCl₂) and sodium sulfide (Na₂S) in the presence of 2-mercaptoethanol (ME) as the organic ligand were well dispersed in H₂O/dimethylformamide solution without any aggregation. In addition, the Mn-doped ZnS nanocrystals (NCs) were synthesized with similar method. Then, ZnS-PMMA hybrids were obtained via free radical polymerization in situ by using ZnS NCs functionalized with methacryloxypropyltrimethoxysilane (MPS). FT-IR characterization indicates the formation of robust bonding between ZnS NCs and the organic ligand. The TEM images show that ZnS NCs are well dispersed in PMMA matrix, and particle size of as-prepared ZnS NCs is about 2.6 nm, in agreement with the computing results of Brus’s model and Debye–Scherrer formula. The photoluminescence measurements present that ZnS NCs, Mn-doped ZnS NCs, and ZnS/PMMA hybrid show good optical properties.     

原子力显微术轻敲模式中探针样品接触过程及相位衬度研究

借助简单的有阻尼受迫振子模型，研究了原子力显微术轻敲模式中探针与样品接触时间t_c、样品的表面形变D_z和相位衬度对探针设置高度z_c及样品杨氏模量E_s的依赖关系.结果发现,t_c与D_z均随E_s及z_c的增大而减小，同时探针与样品作用过程伴随很小的能量耗散.对轻敲过程中相移量φ的研究表明，E_s较大的样品有较小的φ，且φ随 关键词： 原子力显微术 轻敲模式 相位衬度     

基于级联自适应陷波器的正弦波频率估计

常用的传统和现代方法对于噪声环境中正弦信号的频率估计均存在一定的缺陷。本文利用二阶陷波器级联构造自适应陷波器,实现对多个信号频率的估计;采用递推误差信号和递推最小二乘法同时优化各个二阶陷波器的参数。仿真结果表明,该方法对于单频、多频和频率变化等情况均具有较好的估计结果,且对于噪声干扰具有较强的鲁棒性。     

Growth of single-crystal magnetite nanowires from Fe3O4 nanoparticles in a surfactant-free hydrothermal process

Single-crystal magnetite nanowires with average diameter of ca. 20 nm and length of up to several micrometers were prepared by a simple alkaline surfactant-free hydrothermal process. The crystallinity, purity, morphology, and structural features of the as-prepared magnetite nanowires were investigated by powder X-ray diffraction, transmission electron microscopy (TEM) and selected area electron diffraction. The composition and length of nanowires depends on the pH, with higher pH favoring longer nanowires composed entirely of Fe₃O₄. A mechanism for nanowire growth is proposed.     

THE NECESSARY AND SUFFICIENT CONDITIONS FOR THE SOLVABILITY OF A CLASS OF THE MATRIX INVERSE PROBLEM

Censider the solutions of the matrix inverse problem, which are symmetric positive semide finite on a subspace. Necessary and sufficient conditions for the solvability, as well as the general solution are obtained. The best approximate solution by the above solution set is given. Thus the open problem in [1] is solved.     

时变线性系统的稳定性

本文把文[1]、[2]的变换技巧推广到变系数线性系统(i=1,…,n),用函数方法,研究了n=2、3时零解的稳定性,得到了零解稳定的若干判据.有关系数a_(ij)(t)不必都限制为有界.