Airborne engineered nanomaterials such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), functionalized MWCNT, graphene, fullerene, silver and gold nanorods were characterized using a tandem system of a differential mobility analyzer and an aerosol particle mass analyzer to obtain their airborne transport properties and understand their relationship to morphological characteristics. These nanomaterials were aerosolized using different generation methods such as electrospray, pneumatic atomization, and dry aerosolization techniques, and their airborne transport properties such as mobility and aerodynamic diameters, mass scaling exponent, dynamic shape factor, and effective density were obtained. Laboratory experiments were conducted to directly measure mobility diameter and mass of the airborne nanomaterials using tandem mobility-mass measurements. Mass scaling exponents, aerodynamic diameters, dynamic shape factors and effective densities of mobility-classified particles were obtained from particle mass and the mobility diameter. Microscopy analysis using Transmission Electron Microscopy (TEM) was performed to obtain morphological descriptors such as envelop diameter, open area, aspect ratio, and projected area diameter. The morphological information from the TEM was compared with measured aerodynamic and mobility diameters of the particles. The results showed that aerodynamic diameter is smaller than mobility diameter below 500 nm by a factor of 2 to 4 for all nanomaterials except silver and gold nanorods. Morphologies of MWCNTs generated by liquid-based method, such as pneumatic atomization, are more compact than those of dry dispersed MWCNTs, indicating that the morphology depends on particle generation method. TEM analysis showed that projected area diameter of MWCNTs appears to be in reasonable agreement with mobility diameter in the size range from 100 - 400 nm. Principal component analysis of the obtained airborne particle properties also showed that the mobility diameter-based effective density and aerodynamic diameter are eigenvectors and can be used to represent key transport properties of interest.

中文翻译：

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气雾化纳米材料传输特性的测量

机载工程纳米材料，如单壁碳纳米管 (SWCNT)、多壁碳纳米管 (MWCNT)、功能化 MWCNT、石墨烯、富勒烯、银和金纳米棒，使用差分迁移率分析仪和气溶胶粒子质量的串联系统进行表征分析仪，以获得它们的空中运输特性并了解它们与形态特征的关系。这些纳米材料使用不同的生成方法如电喷雾、气动雾化和干式雾化技术进行雾化，并获得了它们的空中传输特性，如流动性和空气动力学直径、质量缩放指数、动态形状因子和有效密度。进行实验室实验以使用串联迁移率-质量测量直接测量空气中纳米材料的迁移率直径和质量。从粒子质量和迁移率直径获得质量标度指数、空气动力学直径、动态形状因子和迁移率分类粒子的有效密度。使用透射电子显微镜 (TEM) 进行显微镜分析以获得形态描述符，例如包络直径、开口面积、纵横比和投影面积直径。将来自 TEM 的形态信息与测量的颗粒的空气动力学和迁移率直径进行比较。结果表明，对于除银和金纳米棒以外的所有纳米材料，空气动力学直径小于 500 nm 以下的迁移率直径为 2 到 4 倍。通过基于液体的方法（例如气动雾化）生成的 MWCNTs 的形态比干分散的 MWCNTs 的形态更紧凑，表明形态取决于粒子生成方法。TEM 分析表明，MWCNT 的投影面积直径似乎与迁移率直径在 100 - 400 nm 的尺寸范围内合理一致。对获得的空气传播粒子特性的主成分分析还表明，基于迁移率直径的有效密度和空气动力学直径是特征向量，可用于表示感兴趣的关键传输特性。TEM 分析表明，MWCNT 的投影面积直径似乎与迁移率直径在 100 - 400 nm 的尺寸范围内合理一致。对获得的空气传播粒子特性的主成分分析还表明，基于迁移率直径的有效密度和空气动力学直径是特征向量，可用于表示感兴趣的关键传输特性。TEM 分析表明，MWCNT 的投影面积直径似乎与迁移率直径在 100 - 400 nm 的尺寸范围内合理一致。对获得的空气传播粒子特性的主成分分析还表明，基于迁移率直径的有效密度和空气动力学直径是特征向量，可用于表示感兴趣的关键传输特性。