含Sr纳米晶粒二氧化钛多孔微球的制备与表征

Sr-doped nanostructured crystalline TiO2 microspheres were fabricated by modifying the bare microspheres with the method of soaking in strontium nitrate solution and heat treatment.The morphology,crystal structure and photoabsorption ability were characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD） and UV-Vis spectrophotometer.The observation of SEM showed that both the bare and Sr-doped microspheres presented the same honeycomb porous morphology.The XRD spectra affirmed that the incorporation of Sr was in the form of strontium titanate(SrTiO3) as eutectic structure with anatase TiO2.The photocatalytic efficiency of Sr-doped TiO2 microspheres was assessed by monitoring the photodecomposition of KN-R dye.The results reveal that Sr-doped microspheres provided a higher efficiency than the unmodified,which was consistent with the analysis results of UV-Vis absorption spectra.Obvious phenomenon of red-shift on UV-Vis spectrum was seen in comparison with the bare microspheres.Both the phenomena of red-shift and the photocatalytic activity improvement were attributed to the synergistic action between SrTiO3 and anatase TiO2.

基于关键节点的域间路由安全机制

BGP作为Internet域间路由的基本协议,其安全问题一直受到学界的关注,特别是安全性与实现难度之间的折中。针对传统解决方案S-BGP(secure BGP)的不足,在定义关键节点KN(key node)的基础上,利用KN对路由信息安全验证的特殊功能,提出了更加轻量级的解决方案——基于关键节点的域间路由安全机制SR-KN(secure routing based on key node)。通过对比分析表明,SR-KN在保证BGP安全的前提下,减少了全网证书规模及存储量,且具有更好的收敛性能。