2002 Fiscal Year Final Research Report Summary
Mechanism of ultrafine particle formation in the atmospheric boundary layer: Nucleation in weakly ionized gases
| Project/Area Number |
12480151
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Kochi National College of Technology |
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Principal Investigator |
NAGATO Kenkichi Kochi National College of Technology, Dept. of Mechanical Engineering, Associate Professor, 機械工学科, 助教授 (80237536)
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| Co-Investigator(Kenkyū-buntansha) |
ADACHI Motoaki Osaka Prefecture University, Research Institute for Advanced Science and Technology, Professor, 先端科学研究所, 教授 (40100177)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Ion-Induce Nucleation / Drift Tube / Cluster Ions / Ion-Molecule Reactions |
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| Research Abstract |
New experimental system employing an ion mobility spectrometer/mass spectrometer (DT-IMS/MS) and a cluster differential mobility analyzer (C-DMA) has been developed for the purpose of investigating the ion-induced nucleation in the atmosphere. The DT-IMS/MS consists of a drift tube and a quadrupole mass analyzer, and can provide three types of data: total ion mobility spectra, mass spectra, and mass-resolved mobility spectra. Using this system, measurements of mobility and mass spectra of ions, and of mobility spectra of ultrafine particles formed via ion-induced nucleation were performed for SO_2//H_2O/Air mixtures. The results showed that the particle formation in the SO_2/H_2O/Air mixtures is the competitive processes of ion-induced nucleation and homogenous nucleation. Relative contribution of both nucleation processes were observed to depend on the water vapor concentrations. Water vapor was shown to act as a source of OH radicals, as well as ligands of cluster ions. It was found for the first time that the ion species produced by corona discharge differ from those produced by radioactive sources.
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