• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.664-670
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• 2010

The study on mechanical behavior of the structure at the site includes experimental method and numerical analysis method. Experimental method is categorized into true-scale test and laboratory model test. A laboratory model test is to monitor the failure mechanism with a model simulated similar with a real ground so as to identify the quantitative result, while a true-scale model test is the approach which enables to identify the potential problems that may occur with a simulated construction situation similar with a real site circumstance. Thus this study was intended to carry out the experimental test of non open-cut excavation by pipe roof method which is mostly common in domestic sites. as well as was aimed at identifying the ground behavior occurred during pipe penetration using laboratory model test. Appropriate reduced-scale model was selected, taking into account of domestic geological characteristics and operation characteristics of traditional and high-speed rail trains and the qualitative evaluation of displacement was carried out based on a certain ground loss volume depending on excavation after categorizing trackbed settlement pattern by depth of top soil.

• 전력전자학회논문지
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• 제9권2호
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• pp.163-170
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• 2004

1960년도부터 컨테이너를 사용한 해상 물동량이 급격히 증가되어 부두에서 처리하여야할 컨테이너 양이 많이 증가되었다. 부두의 운용효율을 증가시키기 위하여 야드 크레인의 정확히 위치 검출이 상당히 중요한 과제이다. 본 논문에서는 엔코더 출력펄스와 적외선센서를 사용하여 정확하고 신속하게 크레인의 절대위치를 측정하는 기법을 제시하였다. 갠추리 바퀴에 직결된 엔코더 펄스를 카운팅하여 갠추리의 이동거리를 측정한 후, 바퀴의 슬립 통에 인하여 발생하는 측정오차를 보상하기 위하여 적외선센서를 사용하였다. 실제 크레인의 1/10 축소한 시뮬레이터로 실험을 수행하여 본 논문에서 제시한 기법의 타당성을 확인하였다.

• 한국분무공학회지
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• 제14권4호
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• pp.153-162
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• 2009

The use of inedible vegetable oils as substitute for diesel fuel in compression ignition engine is of significance because of the great need for edible oil as food, and the reduction of biodiesel production cost etc. Jatropha curcas oil which is a leading candidate for the commercialization of inedible vegetable oils is selected in this study for reviewing the application in CI engine as an alternative fuel. The important properties of jatropha oil (JO) and JO biodiesel are summarized from the various sources in the literature. It is found that five different types of alternative fuel from JO such as neat JO, JO blends with diesel or other fuel, neat JO biodiesel, JO biodiesel blends with diesel or other fuel and degummed JO were extensively examined in the diesel engine. Two different application types of alternative fuels from JO such as preheating and dual fuelling were also tested, It should be pointed out that most of these applications are limited to single cylinder conditions. The systematic study for the selection of effective application method is required. It is clear that the blends of JOME and diesel can replace diesel fuel up to 10% by volume for running the existing common rail direct injection systems without any durability problems. The systematic assessment of spray characteristics of different types of JO and its derivatives for use as diesel engine fuel is also required.

• 한국분무공학회지
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• 제17권3호
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• pp.121-127
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• 2012

The study is to investigate the mixing stability, fuel properties, and macroscopic spray characteristics of diesel-gasoline blended fuels in a common-rail injection system of a diesel engine. The test fuels were mixed diesel with gasoline fuel, which were based volume fraction of gasoline from 0 to 100% in 20% intervals. In order to analyze the blended effect of gasoline to diesel fuel, the properties of test fuels such as density, viscosity, and surface tension were measured. In addition, the spray behavior characteristics were studied by investigating the spray tip penetration and spray angle using a spray images through a spray visualization system. It was revealed that the density, kinematic viscosity and surface tension of diesel-gasoline blending fuels were decreased with the increase of gasoline fuel. The injection quantity of test fuels were almost similar level at short energizing duration condition. On the other hand, the increase of energizing duration shows the decrease of injection quantity compared to short energizing duration. The test blending fuels have similar growth in Spray tip penetration and Spray cone angle.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.172-180
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• 2006

This study was to analyze the effect of mixed fuel composition and mass fraction on the characteristics of evaporating diesel spray and combustion under the various ambient conditions. The characteristics of vaporization distribution and combustion were visualized by laser induced fluorescent method and direct photography. The experiments were conducted in the constant volume vessel and rapid compression expansion machine with optical access. Multi-component fuels mixed i-octane, n-dodecane and n-hexadecane were injected the vessel and rapid compression expansion machine with electronically controlled common rail injector. Experimental results show that fuel vapor formed stratified distribution. And vaporization and diffusion are become actively increasing in mass fraction of low boiling point component. Consequently multi-component fuels were expected to control the evaporating behavior according to their suitable mass fraction.

• 시스템엔지니어링학술지
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• 제17권2호
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• pp.122-128
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• 2021

Despite various economic crises, the domestic parcel delivery market handled 3.37 billion parcels in 2020 while maintaining annual growth due to the activation of e-commerce. In particular, in the case of the metropolitan area, which accounts for about 70% of the nation's parcel throughput, the increase in parcel delivery volume is directly related to the increase in freight vehicles in central area of Seoul,. And it leads to an increase of unnecessary social and environmental costs such as traffic congestion, road damage, and environmental pollution in the city. Therefore, in this paper we proposed the underground urban logistics system utilizing the existing urban rail infrastructure, and establish a conceptual design by operational scenario. In order to establish conceptual design of underground urban logistics system, we use order picking system process, which is use in warehouse, produce result combined ISO/IEC 26702. The results of this study can be usefully used before the underground urban logistics system is introduced.

• 대한환경공학회지
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• 제38권8호
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• pp.459-467
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• 2016

본 연구는 기기중성자방사화분석법을 이용하여 다중이용시설 중 지하철 객차 내 실내공기 중 미세먼지(PM10)의 미량원소 분포특성과 실내공기질을 평가하고, 향후 실내공기질의 효율적인 제어를 위한 객차 내 PM10의 오염원을 평가하고자 하였다. 대전광역시에서 운행 중인 지하철 객차 내에서 채취한 PM10의 평균농도는 $59.3{\pm}14.5{\mu}g/m^3$이었고, 지하철 객차 내 PM10 중 24종의 원소성분을 정량분석한 결과, 농도는 $10^{-3}{\sim}10^5ng/m^3$ 범위에 걸쳐 넓게 분포하였으며, Fe ($12.5{\mu}g/m^3$)의 농도가 특히 높았다. 이는 지하철 브레이크 시스템과 철로 및 차륜 마찰과 같은 지하철 운행에 의하여 Fe가 상당히 부유되기 때문인 것으로 판단된다. 분석된 미량원소 농도를 바탕으로 오염원을 평가한 결과, brake-nonferrous metal particle, resuspended rail dust, fuel combustion, vehicle exhaust, black carbon, Cr-related가 주요 오염원인 것으로 나타났다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권9호
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• pp.911-917
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• 2015

본 논문에서는 함정용 디젤연료를 단기통 커먼레일 디젤엔진에 적용하여 연료분사압력 변화에 따른 분사율 특성, 거시적 분무 특성 및 연료분사시기와 연료압력변화에 따른 연소 및 배기가스 배출특성을 분석하는데 초점을 두었다. 분사율 특성은 Bosch법을 적용한 분사율 측정 시험 장치를 이용하여 분석하였고, 거시적 분무 특성은 정적용기 및 초고속 카메라를 이용하여 분석하였다. 또한, 연료분사시기 및 연료압력 변화를 정밀하게 제어할 수 있는 단기통 엔진을 이용하여 연소 및 배기가스 배출특성을 분석하였다. 30MPa과 50MPa의 분사조건에서 초기 분사율은 50MPa의 분사조건에서 크게 나타났으며, 분무 발달(투과) 또한 동일시간대에서 큰 것으로 분석되었다. 연료분사시기가 지각될수록 실린더 내부 최대 압력과 최대 열발생량은 떨어지는 경향으로 나타났으며, 고압분사조건에서 실린더 내부 최대압력과 최대 열발생량은 다소 큰 것으로 분석되었다. 고압분사조건에서 도시평균유효압력은 낮은 것으로 분석되었고, 연료분사시기가 TDC 쪽으로 지각될수록 도시평균유효압력 및 토크는 증가하는 것으로 나타났다. 연료분사시기가 $BTDC20^{\circ}$(30MPa)와 $BTDC15^{\circ}$(50MPa)에서 질소산화물 발생수준이 가장 높았으며, 일산화탄소는 $BTDC30^{\circ}$를 기준으로 지각될수록 저감되었다.

• 한국환경과학회지
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• 제23권3호
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• pp.511-520
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• 2014

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.

• 대한기계학회논문집B
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• 제30권7호
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• pp.682-691
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• 2006

This study was conducted to assess the effect of mixed fuel composition and mass fraction on spray inner structure in evaporating transient spray under the various ambient conditions. Spray structure and spatial distribution of liquid phase concentration are investigated using a thin laser sheet illumination technique on the multi-component mixed fuels. A pulsed Ar+ laser was used as a light source. The experiments were conducted in a constant volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. Used fuel contain $i-octane(C_8H_{18}),\;n-dodecane(C_{12}H_{26})$ and $n-hexadecane(C_{16}H_{34})$ that are selected as low-, middle- and high-boiling point fuel, respectively. Experimental conditions are 25Mpa, 42MPa, 72MPa and 112MPa in injection pressure, $5kg/m^3,\;15kg/m^3\;and\;20kg/m^3$ in ambient gas density, 400K, 500K, 600K and 700K in ambient gas temperature, 300K and 368K in fuel temperature, and different fuel mass fraction. Experimental results indicate that the more high-boiling point component, the longer the liquid phase it were closely related to fuel physical properties, but injection pressure had no effect on. And there was a high correlation between the liquid phase length and boiling temperature at 75% distillation point.