• Asian Journal of Atmospheric Environment
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• 제5권3호
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• pp.196-203
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• 2011

The main aim of this study is to establish methods of morphological preservation and elemental quantification for individual snow crystals. Individual snow crystals were collected at a height of 20 m above ground level. To stabilize and preserve the original morphologies of the snow crystals, cyanoacrylate, which has been used to fix liquid droplets, was applied (Kasahara et al., 2000). Several different kinds of snow crystals (dendrite, sectored plate, quasi-sectored plate, and hexagonal plate) were successively stabilized using this method. The stabilized snow crystals were pretreated with acetone, and then the elemental components contained in a whole snow crystal were quantified with the Particle Induced X-ray Emission (PIXE) analytical technique. The snow crystal residual composition determined in the present study was dominated by sulfur and mineral components, and the elemental mass showed an apparent crystal size dependence, where the elemental mass gradually decreased as the crystal size increased.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E3호
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• pp.87-94
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• 2005

Wet scavenging by rain drops is a most important removal process of air pollutants. In order to study the scavenging mechanisms of aerosol particles, the characteristics of chemical components in the rain water were examined as a function of the amount of rainfall. Rain water were collected continuously and separated into the soluble and insoluble components. The elemental concentrations in both components were determined by a PIXE analysis. The physical and chemical characteristics of atmospheric aerosols during the rainfall events were measured simultaneously. The elemental concentrations in rain water decreased substantially just after rain started and then gradually declined in subsequential rain fall exceeding 1.0 mm. The large particles were scavenged more easily than the fine particles. Fe, Ti and Si in rain water were in high insoluble state. Contrarily, almost whole of S was dissolved in rain water.

• 한국입자에어로졸학회지
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• 제18권3호
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• pp.69-77
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• 2022

In order to understand the characteristics of fine particles emitted from coal-fired power plant stacks, it is important to analyze the size distribution and components of particles. In this study, particle size distributions were measured using the ejector-porous tube dilution device and an ELPI system at a stack in a coal-fired power plant. Main elemental components of particles in each size interval were also identified through TEM-EDS analysis for the particles collected in each ELPI stage. Particle size distributions based on number and mass were analyzed with component distributions from 0.006 to 10 ㎛. The highest number concentration was about 0.01 ㎛. The main component of the particles consisted of sulfur, which indicated that sulfate aerosols were generated by gas-to-particle conversion of SO2. In a mass size distribution, a mono-modal distribution with a mode diameter of about 2 ㎛ was shown. For the components of PM1.0 (particles less than 1 ㎛), the abundance order was F > Mg > S > Ca, and however, for the components of PM10 (particles less than 10 ㎛), it was in the order of Fe > S > Ca > Mg. The elemental components by particle size were confirmed.

• 한국환경보건학회지
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• 제48권2호
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• pp.66-74
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• 2022

Background: The health effects of particulate matter (PM_2.5) bonded with various harmful chemicals differ based on their composition, so investigating and managing their concentrations and composition is vital for long-term management. As industrial complexes emit considerable quantities of pollutants, higher PM_2.5 concentrations and chemical component effects are expected than in other places. Objectives: We investigated the concentration distribution ratios of PM_2.5 chemical components to provide basic data to inform future major emissions control and PM_2.5 reduction measures in industrial complexes. Methods: We monitored five sites near the Ansan and Siheung industrial complexes from August 2020 to July 2021. Samples were collected and analyzed twice per week in spring/winter and once per week in summer/autumn according to the National Institute of Environmental Research in the Ministry of Environments' Air Pollution Monitoring Network Installation and Operation Guidelines. We investigated and compared composition ratios of 29 ions, carbon, and elemental components in PM_2.5. Results: The analysis of PM_2.5 components at the five sites revealed that ion components accounted for the greatest total mass at approximately 50% while carbon components and elemental components contributed 23~28% and 8~10%, respectively. Among the ionic components, NO₃^- occupies the greatest proportion. OC occupies the greatest proportion of the carbon components and sulphur occupies the greatest proportion of elemental components. Conclusions: This study investigated the concentration distribution ratios of PM_2.5 chemical components in industrial complexes. We believe these results provide basic chemical component concentration ratio data for establishing future air management policies and plans for the Ansan and Siheung industrial complexes.

• 청정기술
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• 제19권4호
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• pp.453-458
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• 2013

배기가스 중에서 비산재는 수은을 산화하거나 흡착하는 능력을 지닌다. 비산재의 수은 산화 및 흡착 효율은 비산재가 가지는 특성에 따라 변하여 일정하지 않다. 본 연구는 비산재 성분과 수은의 반응특성을 이해하기 위하여 비산재 성분물질이 원소수은과 산화수은에 대해 가지는 산화 및 흡착 능력을 평가하였다. 그리고 비산재 시료의 조성에 맞게 합성한 비산재를 시험하였고, 석탄화력발전소에서 수령한 비산재 시료의 결과와 비교하였다. 원소수은에 대해서는 미세탄소분말, 산화구리, 산화철이 높은 산화 또는 흡착효율을 보였고, 염화수은에 대해서는 미세탄소분말, 산화칼슘, 산화구리, 산화마그네슘이 높은 효율을 보였다. 그리고 합성비산재는 비산재 시료와 유사한 수은 산화 및 흡착 효율을 보였다.

• 한국산학기술학회논문지
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• 제9권6호
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• pp.1782-1786
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• 2008

천안시 대기 입자 중 원소 성분의 분포 특성을 파악하기 위해, Cascade Impactor를 장착한 High Volume Air Sampler를 이용하여 대기 입자를 미세입자와 조대입자로 나누어 채취한 후, ICP를 이용하여 16개 원소의 농도를 측정하였다. 측정된 미세입자와 조대입자의 총 질량농도는 각각 평균 33.23, $20.66{\mu}g/m3$ 이었으며, 이 중 총 원소농도는 각각 1.27, $1.71{\mu}g/m3$으로, 전체 질량의 3.8%와 8.3%를 차지하여 조대입자에 원소성분이 상대적으로 많이 분포함을 나타냈다. 미세입자와 조대입자 모두 Fe, Al, Ti이 가장 높은 농도를 나나내는 원소였으며 Pb는 총 농도가 84.55ng/m3으로 국내 기준치를 만족하였다. Al을 기준원소로 분석한 Sc, Cr, Cu, Zn, As, Se, Sn, Pb의 농축계수가 미세입자에서 1,000이상을 나타냈는데, 이는 천안시 미세입자에 포함된 원소 성분의 주요 배출원이 인위적 배출원임을 시사한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.19-24
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• 2000

The objective of this study is to develope a computer simulation model and estimate theoretically the transient performance characteristics of heat exchangers in an automotive air-conditioning system. To do that, the mathematical modelling of heat exchangers, such as evaporator and condenser, is presented first of all. For detail calculation, evaporator and condenser are divided into many sub-sections. Each sub-section is an elemental volume for transient modelling. The elemental volume is assumed to consist of three components, refrigerant, tube with fin, and air, and various properties including temperatures of three components are determined step along sub-sections. The properties of refrigerant R134a and air are calculated directly in the program. The heat transfer coefficients and pressure drop in single or two phase are also calculated by suitable empirical correlations. The overall tendencies of the simulation results were agreed well with those of actual situation.

• 보존과학회지
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• 제20권
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• pp.55-65
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• 2007

석탑 표면 흑화현상에 영향을 끼치는 탄소를 평가하기 위하여 석탑표면의 흑색층을 분석하였다. 원소분석기를 이용하여 총탄소량을 측정하였으며. 원소탄소와 유기탄소는 시료를 산처리하여 탄산염탄소를 제거한 후 OC/EC 탄소분석기를 이용하여 분석하였다. 이들 석탑 표면 흑색시료에서 검출된 원소탄소의 함량은 0.52%로 원소탄소 자체만으로 석탑 표면의 흑화현상을 설명하기에는 충분치 않은 양이나 중요한 역할을 하는 것으로 보인다. 석탑 흑색표면 내 원소탄소의 기원을 살펴보기 위해 석탑주변의 대기미세먼지 (PM-10)를 포집하여 성분을 검토하였다. 대기미세먼지 중에서 가장 높은 비율을 차지하고 있는 것은 이온성분으로 38.4%였으며 토양지각성분이 16.6%. 탄소성분이 38.4%로 측정되었다. 대기의 높은 원소탄소함량(13 wt.%)은 석탑 흑색표면에서 검출된 원소 탄소의 기원으로 판단된다. 대기중의 토양성분 또한 석탑 흑색표면이 함유하고 있는 규산염광물의 기원으로 추정되며, 석탑표면에 축적되어 표면을 어둡게 하는 역할을 한다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1185-1186
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• 2006

In order to obtain specific magnetic properties, it is of paramount importance to increase the alloy density of components fabricated by powder metallurgy. An alternative to increase the density of alloys such as Fe-49Co-2V would be the use of elemental Fe and Co instead of the pre-alloyed powder. Trying to give some insight on the industrial application of this strategy, this paper investigates the replacement of more conventional pre-alloyed Fe-49Co-2V powders with elemental Fe and Co. A previous analysis shows that it is possible to achieve higher densities and leads to a noticeable improvement in some important magnetic properties.

• 한국환경보건학회지
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• 제36권1호
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• pp.61-71
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• 2010

Intensive measurements of airborne respirable $PM_{2.5}$ and inhalable $PM_{2.5}$ were conducted in the downtown area of Iksan city. The $PM_{2.5}$ and $PM_{2.5}$ samples were collected twice a day in the Iksan city of Korea from October 17 to November 1, 2004. The purpose of the study was to determine the inorganic water-soluble components and trace elements of $PM_{2.5}$ and $PM_{2.5}$ in the atmospheric environment and estimate the contribution rate of major chemical components from a mass balance of all measured particulate species. The chemical analysis for PM samples was conducted for water-soluble inorganic ions using ion chromatography and trace elements using PIXE analysis. The mean concentrations of respirable $PM_{2.5}$ and inhalable $PM_{2.5}$ were $51.4{\pm}29.7$ and $79.5{\pm}39.6\;{\mu}g/m^3$, respectively, and the ratio was 0.62. The ion species of $NO_3$, $SO_4^2$, and $NH_4^+$ were abundant in both $PM_{2.5}$ and $PM_{2.5}$. These components predominated in respirable $PM_{2.5}$ fraction, while $Na^+$, $Mg^{2+}$, $Ca^{2+}$ mostly existed in coarse particle mode. Elemental components of S, Cl, K, and Si were abundant in both $PM_{2.5}$ and $PM_{2.5}$. These elements, except for Si, were considered to be emitted from anthropogenic sources, while Si, Al, Fe, Ca existed mainly in coarse particle mode and were considered to be emitted from crustal materials. The averaged mass balance analysis showed that ammonium nitrate, ammonium sulfate, crustal component, and other trace elements were composed of 18.4%, 13.2%, 4.8%, 3.5% for PM2.5 and 17.0%, 11.6%, 13.7%, 4.4% for $PM_{2.5}$, respectively.