Vinyl Polymerization Initiated by Sulfur Dioxide

Abstract

A number of monomers have been polymerized in the presence of catalytic and higher concentrations of SO₂. The addition of t-butyl hydroperoxide greatly accelerates the rate of polymerization. The use of ³⁵SO₂ indicates that at catalytic concentrations of SO₂ (10^?2 mole/liter), only one or two molecules of SO₂ are incorporated in the chain, but, at high SO₂ concentrations, copolymerization of SO₂ with vinyl monomers occurs.     

光学材料激光预处理技术机理研究现状

以机理研究为主线对激光预处理技术进行了回顾。从材料类型和激光参数等方面对预处理的理论与实验结果进行归纳分析,得出预处理效果取决于缺陷在热作用下的演变规律的结论。重点分析了三种定量模型,对比了各模型的优缺点,并指出了未来预处理模型的发展趋势。最后结合机理研究的新方法、工业化应用和进一步提高增益等问题对预处理技术进行了展望。     

A New Butyrolactone Charlesolide and Other Constituents from Roots of Geranium charlesii

Chemistry of Natural Compounds - A new butyrolactone that was called charlesolide and the known phenolic compounds gallic acid (3,4,5-trihydroxybenzoic acid) and its methyl gallate and ethyl...     

Adsorption of organic molecules on a melamine-modified porous polymer

Inverse gas chromatography in the infinite dilution regime was used to study the adsorp-tion of organic molecules on a micromesoporous styrene-divinylbenzene copolymer modified with melamine deposited onto its surface in amounts of 10^–6, 10^–5, 10^–4, 10^–3, 10^–2, and 5?10^–2 weight parts. Contributions of different intermolecular interactions and polarity of the samples to adsorption energy values were calculated using LFER and by Dong method. Contributions of methyl group to Helmholtz adsorption energy and to its dispersion compo-nent were determined. The polarity of the modified samples showed a non-linear dependence on the amount of the deposited modifier (pC): at 4 < pC < 6, it increases as the modifier concentration grows, abruptly falls at pC = 3, and does not change with the further decrease in pC. This is probably caused by the formation of melamine intermolecular associates at higher modifier concentrations.     

表面磁极化子的回旋共振性质

在磁场中有不少的极性晶体,电子和体纵光学声子的耦合弱,而与表面光学声子的耦合强。本文讨论电子和体纵光学声子耦合弱,与表面光学声子耦合强时对表面磁极化子的性质的影响。采用改进了的线性组合算符法导出了磁场中表面极化子的回旋共振频率和回旋共振质量,对AgCl晶体进行了数值计算。结果表明,磁场中表面极化子的回旋共振频率和回旋共振质量随磁场的增加而增加。