论文标题
来自各种来源的烟灰颗粒的尺寸依赖性质量吸收横截面
Size-dependent mass absorption cross-section of soot particles from various sources
论文作者
论文摘要
燃烧生成的烟灰的质量吸收横截面（MAC）用于污染和排放测量中，以量化烟灰的质量浓度和大气建模，以预测烟灰对气候的辐射作用。先前的工作表明，由于（1）烟灰骨料中单体之间的内部散射，烟灰颗粒的Mac可能会随着它们的尺寸而变化，（2）烟灰一级颗粒直径与骨料尺寸的相关性，（3）量子限制效应，或（4）（4）烟灰含量的大小相关程度。在这里，我们报告了一个尺寸依赖的Mac，用于从两个市售扩散的烟灰发电机，一个航空涡轮发动机和一个柴油发电机中采样的前烟灰。我们还合并了文献数据。我们表明，MAC随着骨料的大小增加，直到在4至30 Fg之间达到平稳质量（约300-650 nm的烟灰迁移率直径）。最小的颗粒可能比最大的MAC小50％至80％，具体取决于来源，而最大的颗粒的MAC在以前的测量范围内通过对多分散样品进行的测量报告范围内。此外，我们表明假设（1），（2）和（3）的模型不会描述我们的测量结果，而将假设（4）作为唯一剩下的候选者。
The mass absorption cross-section (MAC) of combustion-generated soot is used in pollution and emissions measurements to quantify the mass concentration of soot and in atmospheric modelling to predict the radiative effects of soot on climate. Previous work has suggested that the MAC of soot particles may change with their size, due to (1) internal scattering among monomers in the soot aggregate, (2) the correlation of soot primary-particle diameter with aggregate size, (3) quantum confinement effects, or (4) a size-dependent degree of soot graphitization. Here, we report a size-dependent MAC for ex-situ soot sampled from two commercially available diffusion-flame soot generators, one aviation turbine engine, and one diesel generator. We also incorporate literature data. We show that the MAC increases with aggregate size until a plateau is reached at single particle masses between 4 and 30 fg (approximately 300-650 nm soot mobility diameter). The smallest particles may have MACs 50% to 80% smaller than the largest, depending on the source, while the largest particles have MACs within the range reported by previous measurements on polydisperse samples. Moreover, we show that models of hypotheses (1), (2), and (3) do not describe our measurement results, leaving hypothesis (4) as the only remaining candidate.
