Electro-copolymerisation of indene and styrene

Electroinitiated cationic copolymerisation of indene and styrene was investigated by constant potential electrolysis. Effects of copolymerisation potential and temperature on the copolymer composition and the reactivity ratios are discussed. The reactivity ratios of the monomers were calculated according to the integrated Lewis-Mayo equation.     

Copolymerization of bromophenylmaleimide with ethyl or butyl methacrylate

N‐p‐Bromophenylmaleimide (BrPMI) does not polymerize in solution by conventional free radical mechanism. However, it readily polymerized in bulk when mixed with a free radical initiator and heated in a microwave oven for 7–8 min. Copolymerization of ethyl methacrylate or butyl methacrylate with BrPMI was conducted in dioxane. The copolymers were characterized by IR and ¹H NMR spectroscopy and gel permeation chromatography. The monomer reactivity ratios were calculated by a non‐linear least‐square analysis. Thermal analysis indicated a great improvement in thermal stability of the copolymers compared with the methacrylate homopolymers. BrPMI was also polymerized in bulk in the DSC pan, which allowed the calculation of the activation energy of its polymerization. Copyright © 2003 Society of Chemical Industry     

镨掺杂分布对1.3μm光纤放大器特性影响

对掺氟化镨玻璃光纤放大器的小信号增益，用广义的高斯近似公式可获得精确的分析表达。文中研究了限制光纤芯层中央部分的镨掺杂对光纤放大器特性的影响，结果发现限制镨掺杂分布能改进光纤放大器的工作效率，且截止波长比芯层全部均匀掺镨的光纤更长。     

APPLICATION OF SITE-SPECIFIC NATURAL ISOTOPE FRACTIONATION (SNIF-NMR) OF HYDROGEN TO THE CHARACTERIZATION OF EUROPEAN BEERS

More than one hundred samples of European beers have been investigated by the new SNIF-NMR method which is based on 2H NMR at the natural abundance level and enables site-specific natural isotope fractionation factors in ethanol to be determined. The relative (R) and absolute (D/H)_i, parameters are shown to be characteristic of the country where the beers are brewed and the observed variations are explained in terms of cereal composition, water resource, and manufacturing processing (fermentation, yeast, temperature cycle). These new parameters find analytical and mechanistic applications in the identification of a beer and in the investigation of a fermentation process.     

红色长余辉发光材料CaTiO3：Pr^3＋余辉性能的改进。

采用掺入Zn来改良红色长余辉发光材料CaTiO3：Pr^3＋的发光亮度及余辉性能．通过对该材料的X射线衍射谱、发光光谱和余辉衰减过程进行分析与测试,发现改变zn的掺入量对该发光粉体余辉性能的影响规律,当Zn^2＋的含量为15％～25％时,发光粉体具有最佳的余辉性质．     

Bayes网络与关系模型的集成:概率关系模型

对象关系模型和Bayes网络分别是关系理论和概率理论两个不同领域中最重要的模型，它们首次集成于本文引入的概率关系模型中，作为新型的概率模型，概率关系模型不仅继承了Bayes网络的大部分优点，而且关系特征和对象的概念使它能有效地克服Bayes网络在许多方面的不足，而成为对复杂系统模建的理想工具，是对Bayes网络的重要创新；作为新型的关系模型，概率关系模型也是对传统关系模型的重要创新，具备概率特征的对象关系模型有了处理不确定性问题的能力。概率关系模型的创建对复杂智能信息系统开发研究有有着特别重要的意义，本文首先评述Bayes网络和对象关系模型，然后在此基础上引入概率关系模型。     

Fatty acid variation among U.S. Runner-type peanut cultivars

Fatty acid composition was determined among seven U.S. runner-type peanut (Arachis hypogaea L.) cultivars: Florunner, Sunrunner, GK-7, Southern Runner, Sunbelt Runner, Okrun, and Langley. Significant year and cultivar differences were found within these fatty acid profiles. Southern Runner had the best oleic to linoleic ratio and iodine values; whereas Florunner, Sunrunner, and Langley were the highest in unsaturated and lowest in saturated and long-chain fatty acids. For the future, breeding programs need to continue developing peanut cultivars with improved oil quality.