• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.7-12
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• 2003

Mixture formation in the cylinder of a lean bum engine has been observed by Laser Induced Fluorescence technique. XeCl laser (308nm) was used to produce a laser sheet. 3-pentanone has been added to iso-octane fuel to produce fluorescence, the intensity of which is proportional to the concentration of the fuel. The laser sheet was introduced through the piston window and the fuel distribution in the vertical plane was observed through a side window. Comparison has been made for the cases of selected fuel injection timing as 0, 360, 405, and 450 CA. For the case of 0 and 360 CA injection, uniform fuel distribution in the combustion chamber has been obtained at the ignition time which is favorable for the high load mode. And the late injection cases, 405 and 450 CA, revealed the stratified formation of rich mixture around the spark plug. That extends the lean misfire limit and reduces cyclic variation in the low load mode.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.93-102
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• 2006

Methyl tert-butyl ether (MTBE), an octane booster that is added to the reformulated gasoline, has been a widespread contaminant in aquatic ecosystem. MTBE is a recalcitrant pollutant having low biodegradability. Due to its higher water solubility and low octanol-water partition coefficient, it can be rapidly transported to the surrounding water environment. Also, MTBE is a known animal carcinogen, and is classified as a possible human carcinogen by U. S. Environmental Protection Agency. The adverse effect of MTBE to aquatic biota was widely reported. In Korea, the recent detection of MTBE in groundwater near gasoline filling stations has drawn concern to public health and ecosystem. To address this concern, the effect of MTBE to human health and ecosystem was discussed in this review. Also, ecotoxicity data of MTBE for fish, invertebrates, and algae were extensively compared to estimate the hazard concentration 5($HC_5$) of MTBE as a screening level.

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.381-383
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• 2009

From Oct. 2008 to Oct. 2009, 619 livestock products sold in Incheon were examined for melamine contamination. HPLC was used to detect the melamine concentration from various products. $C_{18}$ column $(3.9\times150mm,\;4{\mu}m)$ was applied with a phase composed of 10mM citric acid and 10mM sodium octane sulfonate : acetonitrile (in ratio 90:10) pumped isocratically at 1.0ml/min. Melamine was not detected from any of the products at the level of LOD 0.03mg/kg and LOQ 0.08mg/kg, suggesting that no melamine contamination was ascertained in livestock products in Incheon area. However, further tests should be done to detect other melamine analogues for the evaluation of toxicity and safety of melamine and cyanuric acid in the future.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.5
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• pp.589-595
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• 2003

DME(Dimethyl ether) is an oxygenated fuel with a octane number higher than that of diesel oil. It meets the ULEV emission regulation and reduces the smoke to almost zero when used in a diesel engine. In the present study, engine performance and exhaust emissions were investigated with a conventional DI diesel engine which has a jerk type injection pump. Test results showed that the power with DME were almost same as that of pure diesel oil, and the brake thermal efficiency increased a little. Also, smoke index from DME engine showed nearly zero level, but NO$_{x}$ was increased compare to diesel oil.

• Archives of Pharmacal Research
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• v.28 no.9
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• pp.1023-1026
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• 2005

A new furofuran lignan (1) was isolated from the n-butanol fraction of the methanolic extract of the leaves of Petasites japonicus (Sieb. et Zucc.) Maxim. (Compositae). The structure of compound 1 was determined to be $2{\alpha}-(4'-hydroxy-3'-methoxyphenyl)-6{\alpha}-(4"-hydroxy-3"-methox­yphenyl)-8{\alpha}-hydroxy-3, 7-dioxabicyclo[3.3.0]octane\;4'-O-({\beta}-D-glucopyranoside)$ by spectroscopic methods including 2D-NMR. In further studies, it was found that the compound 1 expressed an antioxidant activity in DPPH radical scavenging assay, and moreover, ameliorated the seizure in kainic acid-treated mice.

• Journal of Hydrogen and New Energy
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• v.20 no.1
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• pp.55-63
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• 2009

In this study, thermochemical degradation by acetone solvolysis reaction of siberian spruce wood was investigated for a temperature range of $200{\sim}400^{\circ}C$. The liquid products by acetone solvolysis from siberian spruce wood produced various kinds of aliphatics, cyclic compounds and aromatics included phenols etc. Combustion heating value of liquid products by acetone solvolysis conversion processes was in the range of $8,010{\sim}8,180cal/g$. The energy yield in acetone solvolysis of siberian spruce wood was as high as 74.2% after 40min of reaction at $400^{\circ}C$. The liquid products from the thermochemical conversion of siberian spruce wood could be used as high-octane-value fuels and fuel additives.

• Journal of ILASS-Korea
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• v.14 no.2
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• pp.84-89
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• 2009

In this research, combustion and spray characteristics were investigated experimentally in a constant volume chamber by applying different composition rates of octane number in diesel fuel to a common-rail system. For the visualization, the experiment was carried out under different injection pressures and different cetane number. The test was done by three different types of diesel fuels, the different composition rates of cetane number in diesel fuel and HBD. In summary, this research aims to investigate the combustion characteristics in the application of fuels and compare the results with performance of conventional diesel fuel. This experimental data may provide with fundamentals of the development of diesel engines in future.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.459-468
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• 2002

Literature data measured by the author have been processed to report on the effect of solute structure on gas liquid partition coefficients of eleven normal, branched and cyclic alkanes ranging in carbon number from five to nine in sixty nine low molecular weight liquids. The alkane solutes are n-pentane(p), n-hexane(hx), n-heptane(hp), n-octane(o), n-nonane(n), 2-methylpentane(mp), 2,5-dimethylpentane(dp), 2,5-dimethylhexane(dh), 2,3,4-trimethylpentane(tp), cyclohexane(ch), and ethylcyclohexane(ec). The solvent set encompasses most of those studied by Rohrschneider as well as three homologous series of solvents (n-alkanes, 1-alcohols and 1-nitriles) and several perfluorinated alkanes and highly fluorinated alcohols. An excellent linear relationship was observed between lnK and the carbon number of n-alkanes. The effective carbon numbers of branched and cyclic alkanes were determined in a similar fashion to the method of Kovats index. We found that the logarithm of solute vapor pressure multiplied by solute molar volume was a perfect descriptor for the linear relationship with the median effective carbon number.

• Journal of the Korean Society of Combustion
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• v.5 no.1
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• pp.81-89
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• 2000

An experimental study has been carried on single fuel droplets of water-in-light oil emulsions in an electric furnace to elucidate the dominant factor for the occurrence of micro-explosions. The tests were carried out by changing the following four parameters; the surfactant, the ratio of water to light oil, ambient temperature in electric furnace, and four kinds of fuels having different viscosity(light-oil, kerosene, iso-octane, bunker fuel). The result shows that micro-explosion phenomena is dominated without surfactant and below 30% of water content. Explosion-time is affected by ambient temperature and viscosity of used fuel.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.44-49
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• 2001

Reduced chemical kinetics mechanism has been derived, which can be applicable for autoignition model of hydrocarbon fuels, and contains 23 reactions and 18 species. The present model is validated with the experimental data, where the ignition delays of several hydrocarbon fuels, such as n-heptane, i-octane, n-decane and DME(dimethylether) are measured as equivalence ratios are varied. Especially, the effects of different fuels on ignition delays can be explained by changing the rate constants of three reactions among the present model. As a result, the proposed model can be applicable to two stage ignition model of Diesel combustion.