SGER: Development of Scanning Electron Microscope Techniquesto Ascertain the Microscopic Mixing Characteristics of Atmospheric Aerosols

大多数大气颗粒物的化学分析都是在 批量样品的测试 然而，粒子的变化， 组成强烈影响大气的变化， 能见度下降和颗粒污染物的命运。 在 此外，了解的微观混合特性， 燃烧产物是了解颗粒物的关键 在燃烧中形成。 随着计算机的发展， 控制扫描和X射线检测器， 扫描电子显微镜（SEM）具有很大的 这一应用的承诺。 然而，更多的发展 需要进行工作以确保元素分析准确地 反映了气溶胶的成分。 本研究的目的是获得准确的单 用电子对大气气溶胶进行粒子分析 显微镜 已知组成的单分散气溶胶将是 用于1）进行电子束损伤的研究， 大气气溶胶成分，2）减少光束的试验方法 损害，和3）验证现有的定量方法。 的 还将评估SEM用于测量碳的潜力。 开发的技术将在未来用于识别 元素特性决定水的吸收， 气溶胶

Most chemical analyses of atmospheric particles are carried out on bulk samples. However, particle by particle variations in composition strongly influence atmospheric transformations, visibility degradation, and the fate of particulate pollutants. In addition, knowledge of the microscopic mixing characteristics of combustion products is essential to understanding particle formation in combustion. With the development of computer- controlled scanning and x-ray detectors which measure elements as light as carbon, the scanning electron microscope (SEM) has a great deal of promise for this application. However, more development work is needed to assure that the elemental analysis accurately reflects the composition of the aerosol. The goal of this research is to obtain accurate single particle analyses of atmospheric aerosols with an electron microscope. Monodisperse aerosols of known composition will be used to 1) conduct studies of electron beam damage to major components of atmospheric aerosols, 2) test methods to reduce beam damage, and 3) validate existing quantitation methods. The potential of the SEM for measuring carbon will also be assessed. The techniques developed will be used in the future to identify the elemental characteristics determining the uptake of water by aerosols.