• 한국환경과학회지
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• 제29권5호
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• pp.531-539
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• 2020

To understand the composition, quantity, and quality of Suspended Particulate Organic Matter (SPOM) in the Gangneung Namdae Stream, Korea, we examined spatiotemporal variations in water temperature, salinity, chlorophlly a (Chl a), Particulate Organic Carbon (POC) and nitrogen (PON), and carbon stable isotope (δ¹³C) of SPOM at six stations in June (pre-monsoon), July (monsoon), and September (post-monsoon) 2017. With increasing precipitation, the average POC and C/N values increased significantly in July than in June. In September, the values decreased with decreasing precipitation. The δ¹³C values showed irregular spatiotemporal fluctuations among the stations and periods, thereby suggesting a greater contribution of autochthonous organic matter to the pool of SPOM than that of allochthonous organic matter derived from upstream. In addition, the large and irregular changes in POC, C/N ratio, C:Chl a, and δ¹³C compared to that of PON were observed for all periods among the stations, indicating a serial discontinuity of the stream. Our results suggest that the Gangneung Namdae Stream is significantly influenced by the increase in freshwater discharge caused by heavy rainfalls during the summer monsoon and post-monsoon periods.

• Journal of the korean society of oceanography
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• 제31권3호
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• pp.134-143
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• 1996

Sediment cores were collected from one site each in Amursky and Ussuriysky Bays in the Peter the great Bay for $^{210}Pb$, org C, N, biogenic Si, ${\delta}^{13}$C and ${\delta}^{15}$N analysis to elucidate the processes of biogenic particulate matter accumulation and early diagenetic change in the upper sediment column. Biogeochemistry at the core sites of both bays shows differences in sedimentation rate, sediment mixing, and diagenetic processes of particulate biogenic matter. Sedimentary organic matter at the core sites in both bays appeared to be largely derived from marine origin. Sedimentation rates are 173 and 118 mg $cm^{-2}$ $yr^{-1}$(0.13 and 0.11 cm $yr^{-1}$) in Amursky and Ussuriysky Bays, respectively. The surface mixed layer in the core top was present in Amursky Bay but not in Ussuriysky Bay. At the core site in Amursky Bay, incorporation of biogenic particulate matter into the sediment from the overlying waters is 236, 19, 142 mmol $cm^{-2}$ $yr^{-1}$ for organic C, N, and biogenic Si, respectively. Of which about 70${\%}$ of organic C and biogenic Si are degraded within the upper 25 cm sediment and the rest are buried at 25 cm sediment horizon. At the core site in Ussuriysky Bay, incorporation of biogenic particulate matter into the sediment from overlying waters is 164, 18, 76 mmol $cm^{-2}$ $yr^{-1}$ for organic C, N, and biogenic Si, respectively. Of which less than 50${\%}$ of organic C and biogenic Si are degraded within the upper 25 cm sediment and the remainder are buried at 25 cm sediment horizon. This large difference of degradation of biogenic matter in the upper 25 cm sediment column appears to be resulted from the difference in sediment mixing rates between the two cores.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.113-121
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• 1999

Diesel particulate matter is known to be one of the major harmful emissions produced by diesel engines. Diesel particulates are subject to diesel emission regulations and have lately become the focus in the diesel emission control technology. Thus, the aftertreatment system is adopted at the diesel engine exhaust to reduce the particulate emission. Although this benefit is recognized, it is not clear how the aftertreatment system influences quantitatively the particle size distribution distribution. In this study, the particle size distributions of diesel exhaust were measured using the scanning mobility particle sizer with and without the aftertreatment system. There results showed that the diesel particulate filter and plasm system reduced the number of emitted particles by more than 90% and about 80% respectivley in the particle size range of 20nm∼600nm. On the other hand no significant effect of the diesel oxidation catalyst on the particle number concentration was detected.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.98-103
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• 2013

Conventional method to estimate mass of particulate matter accumulated in diesel particulate filter is to use pressure difference between upstream and downstream of the filter. Then measured pressure difference should be compared that of clean condition which is no particulate matter accumulated in DPF. During regeneration soot oxidation is also estimated by same method. This methodology, however, has demerit on accuracy because of pressure difference deviation of clean DPFs and pressure difference caused by non-carbon based PM which is different from that of caused by carbon based PM. This study suggests new methodology to estimate accumulated soot oxidation rate through exhaust gas characteristics during regeneration. Results, more high accuracy of soot oxidation was obtained by analysis of relationship between fuel mass and concentration of carbon dioxide and oxygen.

• 실내환경 및 냄새 학회지
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• 제17권4호
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• pp.303-314
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• 2018

The urban railway system is a convenient public transportation system, as it carries many people without increasing traffic congestion. However, air quality in urban railway environments is worse than ambient air quality due to the internal location of the source of air pollutants and the isolated space. In this paper, characteristics of particulate matter (PM) pollution in urban railway environments are described from the perspective of diurnal variation, chemical composition and source apportionment of PM. PM concentrations in concourse, platform, passenger cabin, and tunnel are summarized through an analysis of 34 journal articles published in Korea and overseas. This information will be helpful in developing effective policies to reduce PM pollution in urban railway environments.

• 대한화학회지
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• 제44권6호
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• pp.600-610
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• 2000

본 연구에서는 전통적인 입자모델 교수 전략의 문제점을 분석하여, 잘 변화하지 않는 학습자의 신념체계인 연속적인 물질관을 입자적인 물질관으로 변화시킬 수 있는 새로운 입자모델 교수 전략으로 반성적 사고를 촉진시키는 입자모델 교수 전략을 고안하였다. 고안된 반성적 사고를 촉진시키는 입자모델 교수 전략을 초등학교 예비교사를 대상으로 처치한 후, 반성적 사고를 촉진시키는 입자모델 교수 전략의 효과를 전통적인 입자모델 교수전략과 비교 분석하였다. 전통적인 입자모델 교수전략의 문제점으로는 1) 입자모델을 실제물과 연결시켜 생각하지 못하는 문제점, 2) 입자모델을 학습할 때 무조건 암기하는 학습전략을 사용하는 경향이 높은점, 3) 입자모델을 수없이 학습한 후에도 연속적 물질관을 입자적 물질관으로 변화시키지 못하는 학생의 비율이 매우 놓은점, 4) 물질을 학습할 때 과학적 상황으로 학습하므로 물질에 대한 사고가 과학적 상황에 제한되어 있어 일상적 상황으로 연관시키지 못하는 문제점 등이 있다. 전통적인 과학적 상황의 입자모델 교수전략과 반성적 사고를 촉진시키는 일상적 상황의 입자모델 교수전략의 효과를 비교한 결과 일상적 상황의 입자모델 교수전략이 개념이해측면, 흥미측면, 입자적 물질관 형성정도, 기억측면에서 더 효과적인 것으로 나타났다. 본 연구결과로부터 얻을 수 있는 과학교육에의 중요한 시사점은 일상적 상황의 입자모델 교수전략 방법이 과학을 과학적 상황(실험실 상황)에서만 국한되어 사고하는 것이 아니라, 학교 과학 수업시간에 학습한 과학을 일상 상황과 연관시켜 사고할 수 있도록 해 준다는 것이다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2006년도 춘계학술대회 논문집
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• pp.318-319
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• 2006

• 한국입자에어로졸학회지
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• 제6권4호
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• pp.173-183
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• 2010

The high temperature pleated filter bags which were used during this study were made of pleated nonwoven fabric of heat and acid resistant polysulfonate fibers which can withstand the heat up to $300^{\circ}C$ and have a filtration area which is 3 to 5 times larger than the conventional round filter bags. Cartridge module packed with 3 kind of the sulfur impregnated activated-carbon based sorbents were inserted in the inner of the pleated filter bag. This type of pleated filter bag was designed to remove not only the particulate matter but also the gaseous elemental mercury. The electrostatic precipitator part can enhance the particulate removal efficiency and reduce the pressure drop of the pleated filter bag by agglomerated particles to form a more porous dust layer on the surface of the pleated bag which is increased the filter bag cleaning efficiency. In addition, the most of particles are separated from the flue gas stream through the cyclone and the electrostatic precipitator part which were installed at the lower part and main body part of the convergence particulate collector, respectively. Thus reduce particulate loading of the high temperature pleated filter bags were applied in this study to analyze the removal characteristics of particulate matter and gaseous elemental mercury.

• 해양환경안전학회지
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• 제28권7호
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• pp.1252-1258
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• 2022

선박용 엔진에서 배출되는 배기가스에는 다량의 수분과 미세먼지를 포함하고 있다. 미세먼지에는 여과성 미세먼지와 배기 배출 후 액상으로 변화하는 응축성 미세먼지가 포함되어 있으며 배출 전에 걸러지는 고체상 미세먼지보다 응축성 미세먼지가 더 많은 것으로 보고되고 있다. 본 연구에서는 배기가스의 배기열과 수분을 회수하고 응축성 미세먼지를 제거하기 위한 실험장치를 실험실 내의 가스보일러 배기가스를 이용하여 테스트 하였다. 배기가스는 1차적으로 냉각방식으로 수분과 응축성 미세먼지가 제거되고 2차적으로 흡수제 방식에 의해 추가적으로 수분이 제거되었다. 상대습도 측정에 의한 배기가스 수분 제거율을 계산하면 1단계 배기냉각 방식으로 73%, 2단계 흡수제 방식으로 90% 제거되는 것으로 측정되었다. 이 과정에서 응축성 미세먼지는 80~90% 제거되는 것으로 측정되었다. 개발 시스템에 의해 회수된 열은 공정열로 활용할 수 있으며, 회수된 물은 수처리 과정을 통해 공정수로 활용할 수 있다. 또한 현재 관리 규제가 되고 있지 않지만 미세먼지의 주요 원인인 응축성 미세먼지를 효과적으로 제거할 수 있을 것으로 기대된다.

• 한국생산제조학회지
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• 제8권2호
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• pp.50-55
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• 1999

The exhaust emissions from diesel vehicle are known to be harmful to human health and environment. Recently, one of the most environment problems is particulate matter. In this study, through the actual exper iment and heat transfer of exhaust pipe in light duty diesel engine equipped with the ceramic filter trap of throttling type, following results are obtained. 1. In case of light duty diesel engine equipped with ceramic filter trap of throttling type, Power and torque of engine were decreased about 5%, compared with the case without trap system. It means that was not so much effect on base engine performance.2. If the length of exhaust pipe when equipping with ceramic filter trap is suitably controlled, the range of regeneration will be expand much more.3. Particulate matter reduction efficiency of ceramic filter trap system was about 70%-80%, so it was proved a good system to reduce particulate matter.In experiment, test was conducted to estimate engine emission in 2,476cc light duty diesel engine which was equipped with ceramic filter trap.