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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/4249

Title: 1-3 nm标准气溶胶的生成
Other Titles: Development of 1-3 nm standard aerosol nanoparticle generation and measurement system
Authors: 麦华俊
Keywords: 1-3 nm气溶胶
标准气溶胶
电喷雾
差分电迁移率分析仪
气溶胶静电计
粒径分布
1-3nm nanoparticle
standard nanoparticle
electrospray
differential mobility analyzer
aerosol ele
Issue Date: 20130620
Abstract: 1-3 nm标准气溶胶的生成对气溶胶仪器校正、颗粒物的基础科学研究与认识新粒子生成过程具有重要的意义。本研究设计和搭建了一套1-3 nm标准气溶胶生成系统,评测了其工作性能及应用。该系统包括自主设计的电喷雾系统和数据采集电路与供电电路,以及高分辨率差分电迁移率分析仪(HRDMA)和气溶胶静电计。并自主编写了LabVIEW程序实现系统的自动化控制与数据采集。基于上述系统,使用四烷基卤化铵的乙醇溶液和乙酸铵的水溶液,生成了几何粒径在0.7-2.4 nm范围内的严格单分散离子气溶胶,正负离子浓度范围分别为105-106个/cm3与104-105个/cm3,当溶液浓度约为4 mmol/L时能生成最大浓度的单体,而二聚体和三聚体的浓度随溶液浓度增加而增加。基于HRDMA测量的不同正负离子的电迁移率,建立了气溶胶电迁移率粒径与质量间的关系。研究中使用USB显微镜对电喷雾系统中的电喷针顶端进行了实时监测,并建立了电喷雾高压、溶液流速与电喷雾模态间的关系,测试表明当电喷雾系统处于圆锥喷射模式时能比较稳定地产生气溶胶。本研究使用HRDMA、气溶胶静电计,并结合中和器,测量了室内排放源蜡烛燃烧时生成的几何粒径不小于1 nm的不同带电状态颗粒物的粒径分布,并对测量误差进行了计算。实验结果表明,蜡烛燃烧产生较高浓度的几何粒径不小于1 nm的颗粒物,粒径大于3 nm的颗粒物的带电比例高于平衡荷电比例,而1-3 nm范围内,颗粒物带电比例接近荷电平衡状态。
1-3nm standard aerosol generation is a key step in calibrating instruments, examining basic properties and investigating the nucleation mechanism.In this study, a 1-3nm aerosol generation and measurement system was developed and evaluated. The system includes a new ESS, HRDMA, EM and circuits. A LabVIEW program is developed to control the system and collect the data.Several kinds of solution are used to generate standard ions in 0.7-2.4 nm. The number concentrations of the positive and negative ions are within the range of 105-106/cm3 and 104-105/cm3. The concentration of monomer is highest with the solution concentration of 4 mmol/L, while the concentrations of dimer and trimmer are increasing with the solution concentration. The relation between mobility diameter and mass were developed. With a USB microscope, we found the cone-jet mode is shown to be stable in generating nanoparticle.HRDMA, AE and neutralizer are used to measure size distribution of indoor emission down to 1 nm. We found that the burning candle can generate high concentration particles down to 1 nm. The faction of charged particles down to 3 nm is higher than the equilibrium state, while the charged faction of particle is close to the equilibrium state in 1-3 nm.
Description: 66
URI: http://hdl.handle.net/123456789/4249
Source URI: http://oaps.lib.tsinghua.edu.cn/handle/123456789/3177
Source Fulltext: http://oaps.lib.tsinghua.edu.cn/bitstream/123456789/3177/1/005%e9%ba%a6%e5%8d%8e%e4%bf%8a2009010392.pdf
Appears in Collections:Outstanding Thesis of Undergraduate Students 本科生优秀毕业论文(2013)

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