Organosilicon ion‐exchange and complexing adsorbents

Literature data concerning research organosilicon ion‐exchangers and complexing agents have been summarized and systematized. Data on organophilic organosilicon adsorbents and sorption systems for chromatography are not considered here. Copyright © 1999 John Wiley & Sons, Ltd.     

非晶合金结构演变影响玻璃形成能力的分子动力学研究

通过分子动力学方法模拟了Ti75Al25、Ni50Zr50和Cu50Zr50非晶合金的玻璃转变过程, 得到并分析了平均原子体积和双体分布函数等结构参数, 并应用Voronoi多面体指数分析法统计了玻璃转变过程中二十面体及类二十面体团簇的数量, 通过分析团簇在玻璃转变过程中种类和数量的涨落趋势, 研究了非晶原子由短程序连接至中程序再至长程无序的动力学演化过程. 结果表明, 非晶合金的玻璃形成能力以及塑性变形能力与动力学演化过程中Voronoi团簇的种类和数量密切相关. 在玻璃转变过程中局部五次对称性高的团簇倾向于连接在一起形成链,从而密排整个空间, 降低系统的动力学行为从而提高玻璃形成能力. 塑性形变倾向于发生在局部五次对称性较低的区域. 在玻璃转变温度附近团簇种类和数量的突变反映出非晶合金的自组织临界行为, 蕴含着丰富的非线性动力学现象.     

Modeling heat transfer and transcrystallization kinetics during processing of polymer-based composites materials

Transcrystallization phenomena is a key issue to master for better understanding the role on the fiber-matrix interface in composites materials behavior during and after processing. In this paper, a non-isothermal kinetics model is presented to consider crystallization in fiber-based composite with thermoplastic matrix. The model extends Schneider's formulation to describe the development of transcrystalline layers around fibers. It also mentions the possibility to easily account for shear and flow conditions in addition to the transcrystallinity. Another approach, based on the volume fractions, giving the same results, is also introduced for comparison. Then, a parametric study is proposed in order to demonstrate the relevance of the developed model by comparing its results to well-known expecting behavior from the literature. Finally, an attempt is made to compare this model to the one proposed previously in the literature by Durin and al. after correcting some unclear points in the latter.