Microwave hydrothermal synthesis and characterization of ZnO nanostructures in aqueous solution

ZnO nanostructures were prepared in aqueous solution by microwave hydrothermal synthesis. Xray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to characterize ZnO nanostructures (ZNs). The effects of pH, reaction temperature and reaction time on yield of ZnO were investigated. The yield of ZnO increased significantly with the increase of pH value, reaction temperature and reaction time. High yield and well crystallinity of ZNs could be obtained at 120°C for 60min by microwave hydrothermal synthesis. The spherical and rugby-like ZNs were obtained at 120°C without triethanolamine (TEA) and with TEA (mass ratio, $r = m_{Zn^{2 + } }$ : m _TEA = 1: 1), respectively. The concentration of Zn(OH) ₄ ^?2 ions in the reaction solution and TEA had an important effect on the nucleation and morphology of ZnO nanostructures. Mechanism for the formation of ZnO nanostructures was proposed.     

高桩承台底层混凝土整体式承重系统的应用

针对高桩承台基础结构中的底层混凝土施工,以钢套箱作为混凝土的施工模板,结合底板的承重特点,应用整体式承重系统工艺,形成模块化拼装、整体性安装。该工艺既能满足刚度要求,又方便安装和拆卸,缩短了施工时间。