Polymerization of epoxy resins initiated by metal complexes

BACKGROUND: Processing parameters and material properties of epoxy resins can be vastly influenced by choice of curing agent. In this work, metal complexes were investigated as initiators for anionic and cationic epoxide polymerization. Systems for thermally induced and electron beam‐induced curing are described. RESULTS: Zinc or cobalt imidazole complexes of the type [M(imidazole)₂(anion)₂] are efficient initiators for anionic polymerization of glycidyl‐based epoxy resins. The complexes can be employed to prepare tailored resin systems ranging from fast curing systems at slightly elevated temperatures to systems with very high thermal latencies curable at temperatures far above 150 °C. Silver complexes [Ag(L)_n]SbF₆ (L = crown ether or alkene) are highly efficient initiators for cationic curing and low initiator contents of around 1% are sufficient to reach high degrees of crosslinking. The complexes are excellent initiators for both thermally induced and electron beam‐induced polymerizations. CONCLUSION: Metal complexes are powerful initiators for the homopolymerization of epoxy resins and can be designed not only for anionic and cationic polymerization but also for thermal and radiation curing. Based on this study and additional work, a library can be compiled which allows retrieval of optimized metal–ligand–anion combinations and adjustment of the initiators to the respective processing and material demands. Copyright © 2009 Society of Chemical Industry     

蓝宝石单晶光纤高温传感头的热辐射分析

蓝宝石单晶光纤高温传感器是近年来发展的一项高技术成就,本文介绍其基本原理后,着重从理论上分析传感头的热辐射特性,给出了满足理想黑体辐射状态的传感头设计的基本参数,并以实验研究验证了理论分析的结果。     

低能电子冲击下,环己烷的离解

使用自行设计组装调试的离解谱仪,研究了环己烷(C_6H_(12))蒸汽样品在低能电子冲击下的离解产物。实验表明出现的主要产物是质量数为56,68及84的离子。     

在综合换热作用下矩形直肋散热器换热特性

给出了矩形直肋散热器有对流、辐射及导热同时存在的复杂换热问题的一种线性化解析方法。利用该方法，对含有辐射项的非线性微分方程进行了解析求解。分析了对流和辐射对肋效率的综合影响，得出了在综合换热作用下肋散热量的计算公式。     

倾斜转弯导弹自动驾驶仪设计中的前馈问题研究

针对倾斜转弯（ＢＴＴ）导弹自动驾驶仪设计，提出了一种新的解决前馈问题的方法．该方法通过引入低通滤波器和静态补偿控制律解决ＢＴＴ导弹俯仰通道的前馈问题，通过设计三通道协调控制律解决偏航通道的前馈问题．最后，进行了数字仿真，得到满意的结果．     

空空导弹发射包线灵敏度分析研究

提出了用导弹发射包线灵敏度系数来反映发射包线与操纵参数的关系，从而创造发射机会的原理．针对离轴发射导弹进行仿真研究，分析了导弹发射条件的改变对导弹发射包线的影响，并提出将灵敏度因子显示给飞行员，帮助飞行员判定发射包线的变化趋势，便于更好地抓住战机．     

大型锅炉燃烧室三维辐射传热模型及其应用

在网络分析法基础上，建立了一种新的炉内辐射传热三维数值计算方法，并应用于大坝电厂３００ＭＷ机组仿真和哈尔滨锅炉厂６００ＭＷ机组炉内过程全模拟计算。应用结果不但实时性好，同时各排燃烧器运行工况对过热汽温的影响，以及屏式过热器辐射吸热特性都得到充分反映，具有很好的动态响应。     

短背射天线的分柝与计算

本文提出一种用于分析和计算短背射天线表面电流分布和远区辐射场的方法。该方法是将短背射天线的大小反射板按对称振子轴线方向分成许多窄条,等效成平行的线天线阵。求解此天线阵的积分方程,采用数值解法求出各单元天线上的电流分布及短背射天线的辐射特性。     

The effects of intercepted solar radiation on sunflower (<Emphasis Type="Italic">Helianthus annuus</Emphasis> L.) seed composition from different head positions

The effect of intercepted solar radiation during fruit filling on seed weight and oil content from seeds of three sectors of the head in two sunflower (Helianthus annuus L.) hybrids of low and high potential oil percentage was investigated. Seed weight in each sector depended on both the level of radiation intercepted (modified by shading and thinning plants) and the genotype grown. A higher level of intercepted solar radiation increased seed weight in each sector. Central seeds of shaded plants showed the lowest weight. The seed and kernel oil content hierarchy among the three sectors was modified only in the hybrid with high potential oil content. For each head sector, variations in seed oil content associated with changes in the level of intercepted radiation could be accounted for by changes in the kernel oil content, not in the kernel/seed ratio. Significant relationships were found between seed oil and kernel oil contents when analyses between treatments (R>0.86) and sectors (R>0.92) were carried out. These relationships together with the growing conditions of plants during seed filling, the genotype, and the seed position on the head are essential factors that should be taken into account when selecting seeds in sunflower breeding programs since they affect the commercial/industrial quality of seeds.     

子波分析在声辐射和声散射中的应用

文章提出将子波分析用于求解声学中的边界积分方程,能提高现有边界元方法解决工程问题的能力。在子波分析于声辐射和声散射的应用研究中,提出了把积分核函数用级数展开,建立频率响应函数计算的频率迭代技术,大大提高了频率响应函数的计算效率。讨论了子波分析在声学工程数值计算中的研究前景。