• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.153-159
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• 2007

Nano-Particles are influenced on the environmental protection and human health. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for diesel passenger vehicles with DPF. In this study, a diesel passenger vehicle was measured on condition of DPF regeneration and no regeneration on a chassis dynamometer test bench. The particulate matter (PM) emission from this vehicle was measured by its number, size and mass measurement. The mass of the total PM was evaluated with the standard gravimetric measurement method while the total number and size concentrations were measured on a NEDC driving cycle using Condensation Particle Counter (CPC) and EEPS. Total number concentration by CPC was $1.5{\times}10^{1l}N/km$, which was 20% of result by EEPS. This means about 80% of total particle emission is consist of volatile and small-sized particles(<22nm). During regeneration, particle emission was $6.2{\times}10^{12}N/km$, was emitted 400 times compared with the emission before regeneration. As for the particle size of $22{\sim}100nm$ was emitted mainly, showing peak value of near 40nm in size. This means regeneration decreased the mean size of particles. Regarding regeneration, PM showed no change while the particle number showed about 6 times difference between before and after regeneration. It seems that the regeneration influences on particle number emissions are related to DPF-fill state and filtration efficiency.

• Particle and aerosol research
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• v.10 no.3
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• pp.93-97
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• 2014

Condensation particle counter (CPC) has been one of the most important basic instrument for measuring number concentration of submicron aerosols. The principle of the CPC is to expose aerosols to a supersaturated vapor and cool down which causes adiabatic expansion. The particles grow by heterogenous nucleation to a sufficient size for easy detection by optical method. However, for growth by condensation, CPC essentially needs both saturater and condensor causing a heavy system. Therefore, it is hard to install commercial CPC to tethered balloon package system. In this study, we developed customized CPC for tethered balloon package system called Hy-CPC which is lighter and smaller in structure than commercial CPCs, and evaluated activation efficiency and detection efficiency by Hy-CPC using electrostatic method (electrometer and Faraday cup).

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3102-3107
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• 2008

This paper was focused on the particulate matter (PM) on the gasoline and bio ethanol. Bio ethanol as a clean fuel is considered one of the alternative fuels that decreased the PM emission from the vehicle. Particle formation in SI engine was depended on the fuel and engine operating condition. In this paper, Particle number concentration behaviors were analyzed by DMS500 (Differential Mobility Spectrometer) and CPC (Condensation Particle Counter) instrument which was recommended by PMP (Particle Measurement Programme). Particle emissions were measured with various engine operating variables such as air excess ratio ($\lambda$), spark timing and intake valve opening (IVO) at part load condition. In vehicle test, the number of particulate matter was analyzed with golden particle measurement system, which was consist of CVS (Constant Volume Sampler), particle number counter and particle number diluter.

• Asian Journal of Atmospheric Environment
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• v.8 no.4
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• pp.175-183
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• 2014

To visually and chemically verify the rainout of soot particles, a model experiment was carried out with the cylindrical chamber (0.2 m (D) and 4 m (H)) installing a cloud drop generator, a hydrotherometer, a particle counter, a drop collector, a diffusing drier, and an artificial soot particle distributer. The processes of the model experiment were as follows; generating artificial cloud droplets (major drop size : $12-14{\mu}m$) until supersaturation reach at 0.52%-nebulizing of soot particles (JIS Z 8901) with an average size of $0.5{\mu}m$-counting cloud condensation nuclei (CCN) particles and droplets by OPC and the fixation method (Ma et al., 2011; Carter and Hasegawa, 1975), respectively - collecting of individual cloud drops - observation of individual cloud drops by SEM - chemical identifying of residual particle in each individual droplet by SEM-EDX. After 10 minutes of the completion of soot particle inject, the number concentrations of PM of all sizes (> $0.3{\mu}m$) dramatically decreased. The time required to return to the initial conditions, i.e., the time needed to CCN activation for the fed soot particles was about 40 minutes for the PM sized from $0.3-2.0{\mu}m$. The EDX spectra of residual particles left at the center of individual droplet after evaporation suggest that the soot particles seeded into our experimental chamber obviously acted as CCN. The coexistence of soot and mineral particle in single droplet was probably due to the coalescence of droplets (i.e., two droplets embodying different particles (in here, soot and background mineral particles) were coalesced) or the particle capture by a droplet in our CCN chamber.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.741-746
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• 2004

Agglomerated and non-agglomerated SiO$_2$ particles are synthesized in a furnace by oxidation of TEOS vapor. These polydispersed particles are classified with DMA to extract particles. Then these particles are introduced into a thermal precipitator through the ESP(Electrostatic Precipitator) to investigate the themophoretic particle deposition using CNCs(Condensation Nuclei Counter). The efficiency of themophoretic particle deposition according to agglomerated and non-agglomerated particles in the thermal precipitator has been studied as a function of particle size and TEOS mole concentration using monodisperse particles classified by DMA. The results show that the particle deposition efficiency decreases as TEOS mole concentration increases and particle size increases. Thereffre, it is concluded that the thermophoretic deposition efficiency is dependent of the particle morphology.

• Safety and Health at Work
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• v.7 no.4
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• pp.381-388
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• 2016

Background: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. Methods: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. Results: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. Conclusions: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.295-301
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• 2005

The fine particles in the range of $30\~500nm$ are monitored at Hanyang University campus in Ansan using house made DMA (differential mobility analyzer) and commercial CPC (condensation particle counter, TSI inc.) in SMPS mode. The monitoring period is March 16th 2004 through May 7th, 2004. During the monitoring period, Aitken nuclei mode $(30\~100nm)$ particle concentration has a tendency of increase in the morning and evening hours. However, the accumulation mode $(100\~500nm)$ particle concentration stays rather stable than that of Aitken mode.

• Particle and aerosol research
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• v.11 no.2
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• pp.57-61
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• 2015

Atmospheric nano-particles along the altitude is one of the main factors causing severe weather phenomena. It is a challenge to find the precise particle size distribution. One useful instrument includes a scanning mobility particle sizer (SMPS). This measures the size distribution of submicron aerosols. The SMPS consists of a condensation particle counter (CPC), differential mobility analyzer (DMA), high voltage power supplier (HVPS), and neutralizer. Due to the many components, it is difficult to install a commercial SMPS into a tethered balloon package system (Eun, 2011). In this study, we customized a SMPS for the tethered balloon package system called Hy-SMPS. It is portable, compact in structure, and evaluated by TSI SMPS using mono and poly-dispersed particles.

• Journal of ILASS-Korea
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• v.17 no.4
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• pp.185-191
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• 2012

Particulate matters (PM) that is generated by most diesel engine is regulated by the mass concentration measured by the conventional method it had been. Recently, Europe PMP (Particle Measurement Program) decided to start the regulation of vehicle's nano-sized particle number (PN) from the year of 2011 because of nano-particle's higher degree of harm to the human body. So firstly, the standard level of PN emission is introduced in the Euro 5/6 emissions regulation with a limit of $6{\times}10^{11}$ per km for light duty vehicle. Also KPMP(Korea Particle Measurement Program) was organized to copy quickly international technical trend. In this paper, it was investigated the nano-sized PN measurement characteristics for different particle generators between spray type and soot type. And the difference ratio between particle generators, the characteristic of PN concentration, counting efficiency and linearity was analyzed. Then, we make conclusions as followed. When particle diameter is increased, counting efficiency of two generators is decreased. Also Secondary calibration method is more higher 3% than Primary calibration method. Finally, SOF which is included in soot particles is not totally removed so it have great influence on test result of counting efficiency and linearity.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.331-342
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• 2010

Aerosol physical properties have been measured at Pusan National University by using the 16-channel LPC(Laser Particle Counter), and particle characteristics have been examined for the period from Aug. 4 2007 to Dec. 30, 2008. Annual total average, seasonal average, and other averages of the meteorologically classified four categories such as Asian dust, precipitation, foggy, and clear days are respectively described here. Both annually and seasonally averaged number concentration show three peaks at the particle diameter of 0.3, 1.3, and $4{\mu}m$, respectively. However, the first peak for summer season tends to be shifted toward smaller size than other seasons, implying the strong fine particle generation. Meteorological condition shows strong contrast in aerosol concentrations. In Asian dust case, relatively lower number concentrations of fine particles (i.e., smaller than $0.5{\mu}m$) were predominant, while higher concentrations of coarse particles were found particularly for the size bigger than $0.5{\mu}m$. In precipitation day, number concentrations were decreased by approximately 30% due to the removal process of precipitation. Foggy day shows significantly higher concentrations for fine particles, implying the importance of the aerosol condensation process of micro-fine-particle growing to fine-particle. Finally the regressed particle size distribution function was fitted optimally with two log-normal distribution, and discussed the similarities and differences among four categorized cases of the Asian dust, precipitation, foggy, and clear days.