• 한국환경과학회지
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• 제21권6호
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• pp.713-724
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• 2012

Emission rates of biogenic hydrocarbon emitted from broad-leaved trees grown at Jeju Island were estimated using a dynamic enclosure method. Leaf temperature, PAR and relative humidity were monitored during the sampling time. The emission rates of isoprene and monoterpene were measured for five plants(Carpinus laxiflora, Quercus serrata, Styrax japonicus, Quercus acutissima, Quercus crispula) during the sampling period at the Halla mountain sites. Among five tree species, the highest isoprene emission rate of 10.60 ${\mu}g\;gdw^{-1}hr^{-1}$ was observed for Quercus serrata. The seasonal emission rates were the highest during summer and the emission of isoprene was highly affected by light and temperature variations. The highest emission rate of isoprene was occurred between 13:00 and 14:00, but isoprene was not emitted in nighttime because of the absence of light.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.1973-1978
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• 2008

The NOx emission characteristics of DME in counterflow nonpremixed flames were investigated numerically, and brief experiments were carried out to compare the flame shapes and NOx emissions with those of $C_3H_8$ and $C_2H_6$. The DME flames were calculated using Kaiser's mechanism, while the $C_2H_6$ flames were calculated using the $C_3$ mechanism. These mechanisms were combined with the modified Miller-Bowman mechanism for the analysis of NOx. Experimental results show that DME flame has the characteristics of partial premixed flame and the flame length becomes very shorter compared with general hydrocarbon fuels and then, the NOx emission of DME is low as much as 60% of $C_3H_8$. In the calculated results of counterflow nonpremixed flames, the EINO of DME nonpremixed flame is low as much as 50% of the $C_2H_6$ nonpremixed flame. The cause of $EI_{NO}$ reduction is attributed mainly to the characteristics of partial premixed flame due to the existence of O atom in DME and partly to the O-C bond in DME, instead of C-C bond in hydrocarbon fuels.

• 천문학회보
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• 제44권2호
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• pp.44.3-44.3
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• 2019

Since the detection of 3.3-micron PAH (polycyclic aromatic hydrocarbon) and 3.4-micron aliphatic hydrocarbon features in the spectra of Titan (Bellucci et al. 2009; Kim et al. 2011) and Saturn (Kim et al. 2012), respectively, the 3.3-micron feature of gaseous CH4 has been thought to be still the important spectral feature in the 3-micron absorption structures of Titan and Saturn. However, the analyses of the 3.3-and 3.4-micron emission structures of Saturn revealed that the influence of the gaseous CH4 on the structures is rather minimal (Kim et al. 2019). We present synthetic spectra of gaseous CH4, and the PAH and aliphatic haze particles in order to show the degree of influence of their spectra on the 3.3-and 3.4-micron emission structures of Saturn, and we compare these synthetic spectra with currently available observations. We constructed these synthetic spectra using newly developed radiative transfer equations. These equations are able to address detailed radiative processes in the atmospheres containing various gases and haze particles. We expect these radiative transfer equations can also be widely applied to the investigation of radiative transfer processes and the analyses of the spectra of celestial objects such as the Earth, the Moon, planets, and interstellar nebulae.

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.868-876
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• 2014

본 논문에서는 함정에 탑재된 추진용 엔진에 사용되는 디젤연료(MDO)의 분사상태를 가시화가 가능한 단기통 디젤엔진에 적용시켜 전 후 분사시기에 따른 연소특성, 일산화탄소(CO) 및 탄화수소(HC) 배출특성을 규명하고, 연소과정의 가시화를 통하여 연소특성을 분석하는데 초점을 두었다. 전 분사시기가 주 분사시기 쪽으로 지연될수록 실린더 내부 평균유효압력($P_{me}$) 및 최고압력($P_m$)은 상승했으나, 주 분사의 방열율은 저감되고, 일산화탄소 및 탄화수소의 발생량 또한 감소하였다. 후 분사시기가 빨라질 경우 주 분사에 의해 형성된 고온, 고압 하에서 연소가 이루어짐에 따라 실린더 내부 평균유효압력 및 최고압력은 증가하였고, 일산화탄소 및 탄화수소 배출수준 또한 증가하였다. 연소과정을 분석한 결과, 전 분사시기가 늦어질수록 주 분사 시 발생되는 착화지연은 매우 짧아지며, 화염강도는 매우 상승하였다. 분사시기에 관계없이 후 분사 시 착화지연 현상은 발생하지 않았으며, 후 분사시기가 늦어질수록 화염의 강도는 점점 떨어졌다.

• 대한기계학회논문집B
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• 제31권11호
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• pp.926-935
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• 2007

The NOx emission characteristics of DME in laminar coaxial jet and counterflow nonpremixed flames were investigated using experimental and numerical approaches, respectively. The flame structure and NOx emission of DME were compared with those of $C_2H_6$ and $C_3H_8$. The DME flame was calculated using the Kaiser's mechanism, while the $C_2H_6$ and $C_3H_8$ flames were calculated using the $C_3$ mechanism. These mechanisms were combined with the modified Miller-Bowman mechanism for the analysis of NOx. Experimental results show in coaxial jet flame that DME flame has the characteristics of partial premixed flame and the flame length decreases up to 1/3 than that of $C_3H_8$ in the same condition of fuel mass flowrate. Then, the NOx emission of DME decreases to 40% approximately, comparing with that of $C_3H_8$. In the calculated results of counterflow nonpremixed flame, DME flame shows the $EI_{NO}$ decreases up to 50% approximately than those of$ C_2H_6$ and $C_3H_8$ flames when the equivalent fuels are consumed per unit mass and time. Although the overall NOx reaction path of DME is similar with other hydrocarbon fuels, it can be identified that DME flame has a distinct NO reduction mechanism due to the reburning NO chemistry in fuel rich region. From these results, we can conclude that the different NOx emission characteristics of DME flame with other hydrocarbon fuels are attributed to not the temperature increase and the activation of NO reactions due to O atom in DME fuel but the rapid processes of pyrolysis/oxidation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.800-805
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• 2001

Recently, our world is faced with very serious and hard problems related to the air pollution due to the exhaust emissions of the diesel engine. So, lots of researchers have studied to reduce the exhaust emissions which influenced the environment strong. In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for diesel engine. And, we tried to analysis the quantities of the low and high hydrocarbon among the exhaust emissions in diesel engine. It have been investigated by the quantitative analysis of the hydrocarbon $C_1\simC_6$ using the gas chromatography. This study carried out by comparing the chromatogram with diesel fuel and diesel fuel blended DGM(diethylene glycol dimethyl ether) 5%. The results of this study show that the hydrocarbon $C_1\simC_6$ among the exhaust emissions of the mixed fuels are exhausted lower than those of the diesel fuel at the all load and speed. In particular, high boiling point hydrocarbons such as $C_5$ and $C_6$ were reduced remarkably in high speed and load region.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.47-53
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• 2000

To overcome the shortage of conventional TWC that is activated at high temperature, higher than 25$0^{\circ}C$, photocatalyst is considered as an new technology. Because the photocatalytic reaction of photocatalyst is not a thermo mechanical reaction, it is necessary to heat the system to start the reaction. It can be activated just by ultra violet light that includes wavelengths shorter than 400 nanometers even at ambient temperature. In this study photocatalytic reduction of hydrocarbon was investigated with a model gas test. To understand the effects of co-existence gases on the hydrocarbon reduction by photoreaction, CO and NO, $O_2, H_2O$ gases those are components of exhaust gases of gasoline engine are supplied with C3H8/N2 to a photoreactor. The photoreactor contains $TiO_2$ photocatalyst powders and a UV bulb. The results show that oxygen is the most important factor to reduce HC emission with photocatalyst. Photocatalyst seems to have a good probability for automotive application to reduce cold start HC emissions.

• Bulletin of the Korean Chemical Society
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• 제17권2호
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• pp.158-162
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• 1996

The steady-state emission and fluorescence lifetimes of 1,3-dipyrenylpropane were measured in silicate sol-gel and xerogel matrices. In sol solution, the fluorescence emission spectra of monomer and excimer resemble those in hydrocarbon solvents. In gel and xerogel condition, however, the fluorescence spectra exhibit significant change, largely confirming the intramolecular motions in gel pores are influenced by microviscosity. The rate constants for intramolecular excimer formation were obtained from the measured fluorescence lifetimes and the rate processes for excimer forming in silicate sol-gel are described by a simple kinetic scheme.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.39-47
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• 2003

UEGI (Unburned Exhaust Gas Ignition) is an alternative method for fast light-off of a catalyst. It ignites the unburned exhaust mixture using two glow plugs installed in the upstream of the close-coupled catalysts. In addition, a hydrocarbon adsorber was applied to the UEGI, for more effective reduction of HC emission. Engine bench tests show that the CCC reaches the light-off temperature laster than the baseline exhaust system and HC and CO emissions are reduced significantly during the cold start. From the vehicle test, it was observed that a few amount of HC emission was reduced even the catalysts were aged. It is expected to develop a solution kit applicable to a new vehicle or used one, to meet the emission regulation

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.313-316
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• 2012

In this study, the combustion and emission characteristics of waste cooking oil biodiesel was investigated. The fuel was injected from 5 CAD (Crank angle degree) ATDC (After top dead center) to -60 CAD ATDC by 5 CAD with 800 bar and 1600 bar injection pressure. Generally, the hydrocarbon, carbon monoxide and smoke emissions from biodiesel fuel were lower than the emission levels of diesel fuel. However, the emission characteristic of biodiesel got worse than diesel when the fuel was injected earlier than -30 CAD ATDC. $NO_x$ emission from biodeisel was higher than diesel fuel in all experimental conditions.