Synthesis of autophotosensitive hyperbranched polyimides based on 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 1,3,5‐tris(4‐aminophenoxy)benzene via end capping of the terminal anhydride groups by ortho‐alkyl aniline

Benzophenone‐containing, anhydride‐terminated hyperbranched poly(amic acid)s were end‐capped by ortho‐alkyl aniline in situ and then chemically imidized, yielding autophotosensitive hyperbranched polyimides. The polyimides were soluble in strong polar solvents, such as N‐methyl‐2‐pyrrolidone, N‐dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Thermogravimetric analysis revealed their excellent thermal stability, with a 5 wt % thermal loss temperature in the range of 527–548 °C and a10 wt % thermal loss temperature in the range of 562–583 °C. The strong absorption of the polyimide films in ultraviolet–visible spectra at 365 nm indicated that the hyperbranched polyimides were patternable. Highly resolved images with a line width of 6 μm were developed by ultraviolet exposure of the polymer films. A well‐defined image with lines as thin as 3 μm was also patterned, but the lines were rounded at the edges. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2026–2035, 2003     

树枝状醚酰胺多官能团(甲基)丙烯酸酯低聚物的合成及其紫外光固化性能的研究

合成了树枝状(甲基)丙烯酸化醚酰胺低聚物,采用拉曼光谱、光-差热分析和动态力学热分析方法对其紫外光固化动力学和固化膜热机械性能进行了研究.结果表明,这种树枝状低聚物在紫外光照下双键转化率可达80%以上,且其最大反应速率、固化膜的软化温度和玻璃化转变温度随双键浓度的增大而提高.     

Airy函数的零点分布

作为二阶微分方程 f″-zf=0的解 ,Airy函数有可列个零点且均为负数 ,本文借助 Macdonal函数 ,证明了这一重要结论 .其证明过程不涉及整函数阶的问题 ,是一种较为初等的证明方法 .     

平面Laplace外边值问题

证明平面调和函数的Dirichlet外问题解存在唯一的充要条件,在此基础上,确立外问题的等价边界积分方程,首次给出外域上的极值原理,对第一类Fredholm边界的积分方程的可解性进行了讨论。     

实验研究具有周向抽吸轴对称射流的拟序结构

基于实验研究具有周向抽吸轴对称射流拟序结构的动力学行为,定义了临界出口主速度以及超临界工况（低速工况）和亚临界工况。提出了超临界工况下,拟序结构的空间演化特征。基于功率谱确定了超、亚临界工况流动系统发生自激励振荡的速度比范围。     

取样成像扫描式分幅技术

 介绍了用于惯性约束聚变（ICF）等离子体诊断的取样成像扫描分幅技术的原理,分析了该分幅技术的有关特性参数,如曝光时间、画幅数目、空间分辨率等。借助于特别设计的扫描变像管进行了该技术的原理性实验,并利用计算机数字图像处理技术进行图像的重构。实验获得了持续时间约100ps的发光过程的16幅图像,曝光时间优于6.3ps,阴极上空间分辨率为3.5 lp/mm。     

Poisson噪音在小波变换域内的分布特性及去除方法

本文推导出Poisson噪音在小波变换下随尺度变化的变化公式,得出Poisson噪音经小波变换之后其方差随尺度增大而减小的结论,从理论上保证了应用小波变换多尺度方法去除Poisson噪音的可行性与有效性.针对Poisson噪音不具有一致分布性,即它在各点的方差与信号的强度有关,本文提出了一种基于小波变换的变阈值滤波算法,文末的仿真试验结果说明本文提出的算法对去除Poisson噪音是十分有效的.     

奇异强子与核子的相互作用

包含s夸克的强子称为奇异强子,它与核子相互作用的研究近年来有了长足发展 .在指出这种研究的重要意义后,从实验和理论两方面介绍奇异强子 (主要是K介子和超子 )与核子相互作用的研究现状及方法等 ,包括运动学和动力学机制、介子交换模型和夸克模型解释诸方面的问题. We try to highlight some of the key issues regarding the interactions between strange hadron and nucleon, which relate to the kinematics and dynamics mechanism, meson exchange model and quark model. Starting from a brief introduction on the main research goals, we focus on the status of experimental and theoretical investigations of kaon nucleon and hyperon nucleon interactions, which may be considered to be a necessary basis for the studies of nuclear physics with strangeness.