• 대한기계학회논문집B
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• 제39권1호
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• pp.1-9
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• 2015

디젤 자동차의 점점 강화되는 $NO_X$ 배기가스 규제를 만족하기 위해서는 화학공학 기반의 SCR 반응모델을 사용한 모델기반 제어 알고리즘 개발이 필요하다. 본 연구에서는 소형 경유차량을 대상으로 $NO_X$ 를 저감하기 위한 배기 후처리 시스템 모델을 설계하기 위하여 SCR 시스템 모델링과 Rig 실험 및 Matlab 을 이용하여 시뮬레이션 및 검증을 하였다. SCR Rig 실험은 디젤엔진에서 배출되는 배기가스와 같은 성분의 모사가스를 생성하여 공간속도와 온도의 변화에 의한 SCR 의 $NO_X$ 저감효율에 대한 실험 조건 및 데이터를 획득하였다. 또한, 제안된 모델은 Rig 실험에서 사용한 실험조건과 결과데이터를 이용하여 Matlab 을 통해 검증하였으며 시뮬레이션 시 필요한 모델의 파라미터 값들은 실험데이터를 기반으로 최적화하였다.

• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.1001-1006
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• 1998

$WO_3$ based semiconduction sensor have been reported to have excellent sension properties to $NO_x$ gases by many researchers. In this study appropriate $WO_3$ precursor have been chosen and thin film sensors were fabricated by metallo organic deposition process. Their sensing characteristics were investigated as a function of NO concentration, heat treatment, and measuring temperature. Tungsten dichloro triethoxide was found to be a good precursor for $WO_3$ thin film in this method. Samples heat treated at $600^{\circ}C$ showed sensitivity (S) 200 to 50 ppm NO gas when measuring temperature was $150^{\circ}C$.

• 산업기술연구
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• 제23권A호
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• pp.181-186
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• 2003

In this study, we analyzed $NO_x$ and $SO_x$ removal efficiencies by a pulsed corona discharge process and investigated the effect of several process variables. The removal efficiencies of NO and $SO_2$ were measured changing the process variables of initial concentrations of NO, $H_2O$, and $NH_3$, $SO_2$, applied voltage, pulse frequency and residence time. As the applied voltage or the frequency of applied voltage or the residence time increases, the NO and $SO_2$ removal efficiencies increase. The NO and $SO_2$ removal efficiencies also increase by the addition of $O_2$ or $H_2O$, or by using the large diameter of the discharge electrode. The experimental results can be used as a basis to design the pulsed corona discharge process to remove $NO_x$, $SO_x$ and VOCs.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 추계학술대회 논문집
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• pp.98-99
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• 2008

• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.953-956
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• 2002

Excess molar volumes (Vm E ) of binary liquid mixtures: xC6H5CH3 + (1-x1)CH3CN or + (1-x1)C6H5NO2, or + (1-x1)C2H5NO2 have been determined as a function of mole fraction of C6H5CH3 (x) at a temperature of 303.15 K over a entire range of composition. The densities of the binary liquid mixtures were determined by pycnometrically. The VmE values of the mixtures have been found to be negative over the whole composition in order of C6H5CH3 + C6H5NO2, < C6H5CH3 + CH3CN, and < C6H5CH3 + C2H5NO2. The negative magnitude of VmE suggests the presence of intermolecular interaction in the three binary liquid mixtures.

• 대한환경공학회지
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• 제38권5호
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• pp.269-278
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• 2016

수도권지역의 대기오염을 개선하기 위해 수도권 대기환경 개선에 관한 특별법이 제정되었고 2005년부터 시행되었다. 그 결과 수도권의 대기질은 개선되었으나 각 대책의 평가에 대한 연구는 부족하다. 이에, 본 연구는 도로이동오염원의 배출량 저감정책이 질소산화물의 농도저감에 미치는 영향을 정량적으로 분석하고자 하였다. 이를 위해 MM5-SMOKE-CMAQ 모델 시스템을 이용하여 수치모사를 수행하였다. 2007년 수도권 $NO_x$ 저감 배출량은 16,561톤으로서 4.7%의 저감률을 보였다. 여러 대책 중 제작차 배출허용기준강화 대책이 가장 효과적이었다. 지역별 삭감실적은 차이가 커서 서울의 삭감률은 인천과 경기의 약 2배에 달하였다. 결과적으로 $NO_x$ 저감의 효과는 서울 도심에 집중적으로 나타났다. 이동오염원 저감대책에 의하여 서울의 $NO_2$ 농도는 연평균 0.60 ppb (2.0%)저감되었고 인천과 경기는 각각 0.18 ppb (1.5%), 0.22 ppb (1.7%)가 저감되었다. 봄과 겨울의 저감농도는 여름과 가을에 비해 1.5~2.0배 정도 높았다. 도심과 풍하지역으로의 $NO_2$ 저감효과 분산때문에 도심지역의 $NO_x$ 배출량 저감이 직접적인 $NO_2$ 농도 저감에 효과적이지 않았다.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1247-1254
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• 2000

The effects of recirculated exhaust gas on the characteristics of $NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The simultaneous control of $NO_x$ and soot emissions in diesel engines is targeted in this study. The EGR system is used to reduce $NO_x$ emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector has 144 nozzles in 1.0 mm diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration and the mean equivalence ratio calculated by the intake air flow and fuel consumption rate, and the exhaust oxygen concentration measured are used to analyse and discuss the influences of EGR rate on $NO_x$ and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions are decreased and soot emissions are increased owing to the drop of intake oxygen concentration and exhaust oxygen concentration, and the rise of equivalence ratio as the EGR rate rises.

• 한국분무공학회지
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• 제20권3호
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• pp.149-155
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• 2015

With increasing of GDP, the registration number of passenger cars has exceeded 20 million last year in Korea. Especially, the registration number of the diesel engine vehicles has been increasing. However, the WHO(World Health Organization) IARC (International Agency for Research on Cancer) has reported that diesel engine exhaust gas is an one of HAPs, which has carcinogenic for human, and they have designated it to Group 1. To solve this problem, exhaust gas from diesel engines has to be controlled. Thus, it has been controlling by European regulatory standard in Korea. On the other hand, in order to meet the enhanced emission regulations, all manufacturing company applied $NO_x$ control device to vehicles such as EGR (Exhaust Gas Recirculation), SCR (Selective Catalytic Reduction) and so on. However, these devices (EGR, SCR) were operated by difference reaction mechanism respectively, and the composition of exhaust gas would be differenced from that of them. In this study, it was conducted to evaluate variety characteristics on changing of exhaust gas composition by each $NO_x$ control device, and the heavy duty diesel trucks were chosen as experimental vehicles. From the result, it revealed that vehicles (with EGR) were discharged higher THC as 52.5% than that of others (with SCR). However, it did not followed that trend, in the case of CO; it was discharged as 57.2% lower than that of others (with SCR). In the future, these data would be used to apply to efficient $NO_x$ control device for meeting to EURO 6.

• Journal of Advanced Marine Engineering and Technology
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• 제24권3호
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• pp.70-78
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• 2000

The effects of recirculated exhaust gas on the characteristics of ;$NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The purpose of the present study is to develop the EGR control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal apparatus with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector is made up 144 nozzles with 1.0mm in diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration obtained by the intake air flow and the oxygen concentration in the recirculated exhaust gas, and the exhaust oxygen concentration measured in exhaust manifold are used to analyse and discuss the influences of EGR on NOx and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions decrease and soot emissions increase owing to the drop of intake oxygen concentration and exhaust oxygen concentration as EGR rate rises. Also, one can conclude that it is sufficient for the scrubber EGR system with a novel diesel soot removal apparatus to reduce $NO_x$ emissions, but not to reduce soot emissions.

• 한국대기환경학회지
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• 제28권1호
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• pp.94-104
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• 2012

The purpose of this research is to quantify the compliance of on-road emission from a light duty diesel vehicle, based on a comparison to emission regulation standard. $NO_x$, CO and THC emissions were measured using a portable device on a selected real-world driving route with a length of approximately 22 km. On-road measurements were repeated by 10 times on a same route to reflect variability in traffic conditions. A test route was divided into 22 road links with length of 1 km to analyze emission results with higher spatial resolution. The average emissions of $NO_x$, CO and THC over total travel distance, which is approximately 220 km, were quantified to be in compliance with emission regulation standards. Under higher spatial resolution, $NO_x$ concentration exceeded a standard in 92 links out of 220 links. The extended time in stop period and the stop-and-go driving cycle were identified as two important reasons for increased $NO_x$ emissions in observed cases. Heavy traffics showed higher $NO_x$ emissions than free flow. These results indicate that the real-world vehicle emissions might exceed the compliance level associate with traffic conditions. Another interesting observation of this research is that the on-road emission characteristics can be independent to the average speed of road links with higher spatial resolution. Variability in on-road emission might not be fully described by solely relying on an average speed, because variability in traffic conditions and road conditions can influence on real-world vehicle emissions.