一种新型液晶环氧树脂的合成表征与固化研究

首次合成了一种不对称联苯和芳香酯型液晶环氧树脂4"-环氧丙氧基苯甲酸-4-环氧丙氧基联苯-4'-酯(EBEPC),利用FT-IR、1H NMR、DSC和POM对其结构和性能进行了表征.结果表明,EBEPC在190℃时可形成明显的向列相液晶.对其同普通固化剂DDM体系的固化反应过程、固化动力学进行了研究,与普通环氧树脂E-51/DDM体系比较,液晶环氧树脂EBEPC体系具有较低的固化反应温度,且表观话化能Ea(54.5kJ/mol)较E-51/DDM体系(60.7kJ/mol)低,EBEPC体系具有更高的反应活性.     

Two-component Brownian coagulation: Monte Carlo simulation and process characterization

The compositional distribution within aggregates of a given size is essential to the functionality of composite aggregates that are usually enlarged by rapid Brownian coagulation. There is no analytical solution for the process of such two-component systems. Monte Carlo method is an effective numerical approach for two-component coagulation. In this paper, the differentially weighted Monte Carlo method is used to investigate two-component Brownian coagulation, respectively, in the continuum regime, the free-molecular regime and the transition regime. It is found that (1) for Brownian coagulation in the continuum regime and in the free-molecular regime, the mono-variate compositional distribution, i.e., the number density distribution function of one component amount (in the form of volume of the component in aggregates) satisfies self-preserving form the same as particle size distribution in mono-component Brownian coagulation; (2) however, for Brownian coagulation in the transition regime the mono-variate compositional distribution cannot reach self-similarity; and (3) the bivariate compositional distribution, i.e., the combined number density distribution function of two component amounts in the three regimes satisfies a semi self-preserving form. Moreover, other new features inherent to aggregative mixing are also demonstrated; e.g., the degree of mixing between components, which is largely controlled by the initial compositional mass fraction, improves as aggregate size increases.     

冰雪运动雪上摩擦学与雪蜡研究现状

冬奥冰雪运动摩擦阻力影响运动健儿成绩,减少滑雪板与雪面之间摩擦阻力,有助于提升滑雪时的行进速度,提高运动员成绩排名. 研究冰雪表面摩擦学,有助于认识冰雪表面水润滑机理,为设计高性能滑雪板和雪蜡材料提供相关的研究基础. 因此,本文作者从冰雪表面摩擦学开始,简要介绍冰雪表面水润滑机理及影响冰雪表面摩擦学性能的影响因素,如环境参数(运动环境的温度/湿度)、雪基参数(雪面硬度、密度,雪面温度/湿度、冰晶大小、雪面污染物)、滑雪板基底参数及雪蜡的使用等;着重介绍了滑雪运动必备的材料-滑雪板减阻蜡的作用和分类,含氟雪蜡对人员环境的危害,雪蜡的选择与打蜡方式对雪板减阻性能的影响以及国内外现有的冰雪摩擦测试装置. 最后,对我国现有冰雪摩擦学基础研究,冰雪运动摩擦学及雪蜡材料的应用开发研究提出了几点建议和期望.      

柔韧性羧端基不饱和聚酯粉末涂料的研制

本文研制了粉末涂料用柔韧性羧端基不饱和聚酯树脂及其相应的环氧树脂固化的柔韧性不饱和聚酯粉末涂料，讨论了树脂合成，涂料制备及涂层性能，涂层的装饰性能特别是柔韧性能有了较大改善。     

广州化学第33卷（2008年）总目次

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光学塑料零件粘接用胶的选择与改性

光学塑料和其它工程塑料一样，由于表面能低，胶液在其表面难以润湿和粘合。为提高光学塑料零件的粘接性能，需寻求适合于光学塑料零件的粘接材料。根据相似相溶的原理，趋向于选用与光学塑料材料分子结构相似的树脂作为光学胶的基本粘料。本文介绍了聚甲基丙烯酸甲酯（ＰＭＭＡ）和聚本乙烯醇薄膜（ＰＶＡＬ）等光学塑料零件与光学玻璃零件粘接时的有关情况。作为光学粘接材料主要选用ＪＮ－７９１光学环氧树脂胶并掺入［Ｎ·Ｓ］硅烷偶联剂的改性胶和以环氧丙烯酸酯为光敏树脂的ＧＢＮ－５０１光学光敏胶。本文着重就相似相溶原理以及为提高粘接性能的作用机理作了初步的探讨。     

碱金属碳酸盐催化合成酚酞环氧树脂

在碱金属碳酸盐（Ｋ＿２ＣＯ＿３，Ｎａ＿２ＣＯ＿３）／Ｈ＿２Ｏ催化下制备了低分子量酚酞环氧树脂．用ＩＲ、￣１ＨＮＭＲ表征了其分子结构，测定了树脂产物的环氧值Ｅ和数均分子风及分子量分布，讨论了单体的摩尔比，催化剂含量及水含量对产物的影响，结果表明，在实验范围内，改变酚酞与环氧氯丙烷的摩尔比（１：１０～１：４）或酚酞与催化剂的摩尔比（１：２～１：１），均可以得到低分子量酚酞环氧树脂（５００～７００）．     

Invariants of Multi-Component Ermakov Systems

It is shown that certain multi-component Ermakov systems admit Lewis-Ray-Reid invariants. This extends the result to the two-component Ermakov system.     

Vector Solitons and Soliton Collisions in Two-Component Bose-Einstein Condensates

With realistic parameters, both analytical and computational studies demonstrate the feasibility of forming bright-bright vector solitons in a self-repulsive two-component Bose-Einstein condensate with attractive intercomponent interaction. Moreover, the stability of such solitons is confirmed by direct numerical simulations, by a Bogoliubov spectrum analysis, and by examining the collisions between two vector solitons. Our results are of considerable experimental interest.