表面活性剂对NBR硫化胶结构的影响

利用X-光结构分析法,就表面活性剂对NBR硫化胶力学性能的影响进行了研究。通过对衍射图中反射图形的分析研究,探明了硬脂酸锌的液晶结构对NBR硫化胶拉伸强度的影响,尤其是在伸长率<300%拉伸条件下对NBR的耐臭氧性会产生严重的影响。为此,文中提示人们要注意在生胶合成的末尾阶段,必须彻底清除生胶中的乳化剂。

Upconversion Luminescence of Er^3＋ and Co-Doped Er^3＋/Yb^3＋ Novel Transparent Oxyfluoride Glasses and Glass Ceramics： Spectral and Structural Properties

Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition （1） SiO2-PbO-PbFE-Er2O3, （2） SiO2-GeOE-PbO-PbFE-Er2O3 （3） SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3＋ and co-doped with Er^3＋/Yb^3＋ ions were synthesized. X-ray diffraction analysis （XRD） and Er3＋ absorption spectra revealed precipitation of PbF2 nanocrystals dispersed in the glassy matrix. Under 980 nm laser excitation, intense green, red and near IR bands of upconversion luminescence （UCL） were recorded both before and after heat treatment. In the glass ceramics the upconversion intensity increased significantly. To our knowledge, for the first time the composition of the glass ceramics characterized by the small-angle neutron scattering （SANS） showed the cluster organization of PbF2 nanocrystals.