Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.

央地关系改革的合理方向

改革推进中的央地关系与改革央地关系,是两个相互关联、但又各自独立的议题。如果不能正确地处理央地关系,就难以按照十八届三中全会的蓝图全面推进改革;而从财政和公共服务及事责的角度、国有企业和国有资产的角度、权力分配和民主治理的角度来看,央地关系存在更加基础性的问题。按照传统的分久必合、合久必分的逻辑不可能理清央地关系,应该从现代政府职能的角度来重新思考这个问题。总体而言,央地关系改革的方向就是水平性分工和当地化委托—代理,用这样的方法来推进中国改革,才有可能出现一个竞争优化的有序格局。