• Korean Journal of Materials Research
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• v.20 no.2
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• pp.78-81
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• 2010

Surface modification of silica nanoparticles was investigated using an aerosol self assembly. Stearic acid was used as surface treating agent. A two-fluid jet nozzle was employed to generate an aerosol of the colloidal suspension, which contained 20 nm of silica nanoparticles, surface modifier, and ethyl alcohol. Powder properties such as morphology, specific surface area and pore size distribution were analyzed by SEM, BET and BJH methods, respectively. Surface properties of the silica power were analyzed by FT-IR. The OH bond of the $SiO_2$ surface was converted to a C-H bond. It was revealed that the hydrophilic surface changed to a hydrophobic one due to the aerosol self assembly. Morphology of the surface treated powder was nanostructured with lots of pores having an average diameter of around $2\;{\mu}m$. Depending on the stearic acid concentration (0.25 to 1.0 wt%), the pore size distribution of the particles and the degree of hydrophobicity ranged from 1.5 nm to 180 nm and 29.6% to 50.2%, respectively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.419-420
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.158-160
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.402-403
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• 2010

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.367-372
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• 2002

Asian dust aerosol layer of 4-6 km altitude accompanied by low clouds was observed by LIDAR and sky-radiometer in Tokyo urban area on April 10, 2001. To synthesize the top of atmosphere (TOA) reflectance, radiative transfer simulation conducted assuming aerosol/cloud vertical structure and aerosol size distribution that were modeled after the ground observations. The refractive index of Asian dust is derived from a laboratory measurement of sampled Chinese soil particles. The synthesized TOA reflectance is compared to the SeaWiFS-derived one sampled at the low cloud pixels whose airmass is the same as the one passed at the observation site. While the two TOA reflectances compare generally well with few percent difference in reflectance, possible sources of the discrepancy are discussed.

• Journal of Powder Materials
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• v.20 no.2
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• pp.129-133
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• 2013

In this paper we have studied the effect of water droplet size on nano-particle size distribution using SMPS(Scanning Mobility Particle Sizer)system. It can be seen that the unknown peak at >100 nm was caused by water droplets which did not dry completely when DI water was used as a solvent in the SMPS system. Therefore, it is important to dry water droplets generated from atomizer in the SMPS system when measuring the particle size distribution using less than 100 nm nano-particles in diameter. From this study, It can be concluded that the napion was a useful material as dryer ones and using EAG(Electro Aerosol Generator) as a particle generator was the most effective in reducing the effect of water droplets.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.83-84
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• 1999

시정악화나 광화학 스모그를 비롯하여 지구 온난화에 부유 입자상 물질이 미치는 영향 등을 파악하기 위해선 중량농도, 화학적 성분분석 등과 함께 그 입경별 크기 분포도 반드시 고려되어야만 한다. 입경분포 측정을 위하여 다단식 임팩터(Cascade Impactor)나 광학입자계수기(OPC, Optical Particle Counter), Aerosizer, SMPS (Scanning Mobility Particle Sizer), EAA(Electrical Aerosol Analyzer) 등 이주로 사용되고 있다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.158-159
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• 2000

내기중의 입자 (aerosol)는 크게 직경이 0.01-0.1 $\mu\textrm{m}$ 대의 Aitken mode와 0.1-1 $\mu\textrm{m}$ 부근의 accumulation mode, 그리고 1 $\mu\textrm{m}$ 이상의 coarse mode로 분류할 수 있으며 대기 중에서 부유하여 서로응집(coagulation) 과 응축(condensation)풍의 과정을 겪으며 변화한다. 일반적으로 Aitken mode 의 입자들은 nucleation 둥에 의해 발생된 입자이며, accumulation mode는 Aitken mode입자간의 응집, 인위적인 배출 둥에 의하여 생성된 입자이다. Coarse mode는 주로 자연적으로 생성된 입자이며 주로 침적에 의해 제거된다. (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.232-235
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• 2003

In general, the parameters of climate change include aerosol chemical compounds, aerosol optical depth, greenhouse gases(carbon dioxide, CFCs, methane, nitrous oxide, tropospheric ozone), ozone distribution, precipitation acidity and chemical compounds, persistent organic pollutants and heavy metals, radioactivity, solar radiation including ultra-violet and standard meteorological parameters. Over the last ten years, the monitoring activities of Korea regarding to the climate change have been progressed within the WMO GAW and ACE-Asia IOP programs centered at the observation sites of Anmyeon and Jeju Gosan islands respectively. The Greenhouse gases were pointed out that standard air quality monitoring techniques are required to enhance data comparability and that data presentation formats need to be harmonized and easily understood. Especially, the impact of atmospheric aerosols on climate depends on their optical properties, which, in turn, are a function of aerosol size distribution and the spectral reflective indices. Aerosol optical depth and single scattering albedo in the visible are used as the two basic parameters in the atmospheric temperature variation studies. The former parameter is an indicator of the attenuation power of aerosols, while the latter represents the relative strength of scattering and absorption by aerosols. For aerosols with weak absorption, surface temperature decreases as the optical depth increases because of the domination of backscattering. For aerosols with strong absorption, however, warming could occur as the optical depth increases. The objective of the study is to characterize the means, variability, and trends of Greenhouse gases and aerosol properties on a regional basis using data from its baseline observatories in Korea peninsula. A further goal is to understand the factors that control radiative forcing of the greenhouse and aerosol.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.437-450
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• 2004

Extensive forest fire activities occurred across the border in Russia, particularly east of Lake Baikal between the Amur and Lena rivers in May 2003. These forest fires released large amounts of particulates and gases into the atmosphere, resulting in adverse effects on regional air quality and the global radiation budget. Smoke pollution from the Russian fires near Lake Baikal was transported to Korea through Mongolia and eastern China. On 20 May 2003, a number of large fires were burning in eastern Russian, producing a thick, widespread pall of smoke over much of Northeast Asia. In this study, separation technique was used for aerosol retrieval application with imagery from MODIS aboard TERRA satellites. MODIS true-color image shows the location of fires and the grayish color of the smoke plumes over Northeast Asia. Aerosol optical thckness (AOT) retrieved from the MODIS data were compared with fire hot spots, ground-based radiation data and TOMS -based aerosol index data. Large AOT, 2.0-5.0 was observed on 20 May 2003 over Korea due to the influence of the long range transport of smoke aerosol plume from the Russian fires, while surface observed fine mode of aerosol size distribution increased.