• 한국자동차공학회논문집
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• 제7권7호
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• pp.104-112
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• 1999

An experimental study for reducing the exhaust hydrocarbon emission at spark ignition engine using timed secondary air injection is carried out . In this study, secondary air injection timings and durations are controlled to decrease the hydrocarbon emission and to increase exhaust gas temperature at cold and warm-up engine conditions. The hydrocarbon reduction rate and exhaust gas temperature are compared between timed secondary air injection and continuous air injection. The optimum secondary air injection timing for reducing the hydrocarbon emission is at the exhaust valve open timing. At some engine conditions , the hydrocarbon emissions are decreased to 10% of engine raw values and exhaust gas temperatures increase by 20$0^{\circ}C$ with times secondary air injection . Timed secondary air injection has more hydrocarbon reduction rate that continuous secondary air injection except some engine conditions.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1656-1667
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• 1997

Condensing heat transfer characteristics of hydrocarbon refrigerants are experimentally investigated. Single component hydrocarbon refrigerants (propane, isobutane, butane and propylene) and binary mixtures of propane/isobutane and propane/butane are considered as test fluids. Local condensing heat transfer coefficients of selected refrigerants are obtained from overall conductance measurement. Average heat transfer coefficients at different mass fluxes and heat transfer rates are shown and compared with those of R22. Pure hydrocarbon refrigerants have higher values of heat transfer coefficient than R22. It is also found that there is a heat transfer degradation for hydrocarbon mixtures due to composition variation during condensation. Measured condensing heat transfer coefficients are compared with predicted values by available correlations. An empirical correlation for pure and mixed hydrocarbon is developed, and it shows good agreement with experimental data.

• 한국연초학회지
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• 제12권2호
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• pp.77-83
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• 1990

This study was conducted to develop the method of hydrocarbon analysis and investigate hydrocarbon contents in flue-cured and burley tobacco leaves harvested in Korea and U.S.A. Tobacco leaf was extract with hexane in soxhlet apparatus. Hydrocarbon was fractionated from hexane extract by silica gel column chromatography, and then separated and indentified by GC, GC/MS using SE-54 fused silica capillary column. The developed method was feasible to analyze neophytadiene, normal and branched hydrocarbons from Clo to Cn. The result of recovery test was decade 99%, eicosane 100%, triacontane 102%. The major hydrocarbon of tobacco leaves were neophytadiene, nC3l, iC31, nC33, aC33, aC32, aC30 and nC29. The amount of total hydrocarbon in burley and flue-cured tobacco leaves harvested in U.S.A. and Korea were 4591, 2931, 2929 and 3015$\mu\textrm{g}$/g, respectively.

• 오토저널
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• 제13권3호
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• pp.25-31
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• 1991

The formation process of hydrocarbon emissions was investigated in SI engine. The time- resolved concentrations of hydrocarbon emissions were measured using a high gas sampling valve and a gas chromatography. The gas was sampled at exhaust port, or the position of spark plug, or the wall of combustion chamber. The experiments were conducted using the Alpha engine of Hyundai Motor Company. The fuel used was methanol or propane. It was found that the effect of the quenching layer of combustion chamber wall on hydrocarbon emissions was not significant. The increasing rate of hydrocarbon concentration at combustion chamber wall near crevice and oil layer after flame was reached was much higher than that at the position of spark plug. The hydrocarbon concentrations at exhaust port had two peak values just after opening exhaust valve and just before closing it.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.399-406
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• 2006

The smoke emission of diesel engines is being recognized as one of the major source of the air pollution problems. This study investigates the potential of esterified rice bran oil to reduce smoke emission as an alternative fuel for diesel engines. Because the esterified rice bran oil has approximately a 10.5% oxygen content, the combustion of the diesel engine improved and exhaust smoke decreased. Gas chromatography was used to analyze not only the total amount of hydrocarbon but also the amount of hydrocarbon components from $C_1$ to $C_6$ in the exhaust gas to determine an exact source responsible for the remarkable reduction in the smoke emission. The number of individual hydrocarbon($C_1{\sim}C_6$) as well as the total amount of hydrocarbon of esterified rice bran oil reduced significantly compared to that of hydrocarbon of diesel fuel.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.181-189
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• 1998

In order to investigate the effect of base oil composition on the electronic insulating oil's performances, an experimental study has been conducted using different oils. Owing to their properties, like lower pour point and gas absorbing, naphthenic base oils are used more often than paraffmic base oils for the electronic insulating oil application. Naphthenic and paraffinic base oils are significantly different in their aromatic hydrocarbon content. In this paper, PXE(para xylyl ethane), LAB(linear alkylbenzene), C13 aromatic hydrocarbon mixture and C17 aromatic hydrocarbon mixture are investigated regarding their influence on insulating oil's performances. According to present study, breakdown voltage decreased with increasing aromatic lydrocarbon content in a deep dewaxed paraffmic base oil. However, any changing in the dissipation factor was not recognizable at small treated level. Furthermore, the volume resistance was not influenced by aromatic hydrocarbon content. The gassing tendency was found as a highly sensible property, changing with treating aromatic hydrocarbons. The higher benzene ring content in the hydrocarbon, the better gassing tendency.

• Journal of Microbiology
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• 제44권3호
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• pp.354-359
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• 2006

This study examined the capacity of immobilized bacteria to degrade petroleum hydrocarbons. A mixture of hydrocarbon-degrading bacterial strains was immobilized in alginate and incubated in crude oil-contaminated artificial seawater (ASW). Analysis of hydrocarbon residues following a 30-day incubation period demonstrated that the biodegradation capacity of the microorganisms was not compromised by the immobilization. Removal of n-alkanes was similar in immobilized cells and control cells. To test reusability, the immobilized bacteria were incubated for sequential increments of 30 days. No decline in biodegradation capacity of the immobilized consortium of bacterial cells was noted over its repeated use. We conclude that immobilized hydrocarbon-degrading bacteria represent a promising application in the bioremediation of hydrocarbon-contaminated areas.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.507-510
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• 2007

Piston cores retrieved from the western Ulleung Basin, East Sea were analyzed to examine the potential for hydrocarbon generation and to determine the hydrocarbon indicators. 2D multi-channel reflection seismic and Chirp data were also investigated for mapping and characterizing the geophysical hydrocarbon indicators such as BSR (bottom simulating reflector), blank zone, pock-mark etc. High organic carbon contents and sedimentation rates that suggest good condition for hydrocarbon generation. High pressure and low temperature condition, and high residual hydrocarbon concentrations are favor the formation of natural gas hydrate. In the piston cores, cracks generally oriented to bedding may indicate the gas expansion. The seismic data show several BSRs that are associated with natural gas hydrates and underlying free gas. A number of vertical to sub-vertical blank zones were well identified in the seismic sections. They often show the seismic pull-up structures, probably indicating the presence of high velocity hydrates. Numerous pockmarks were also observed in the Chirp profiles. They may indicate the presence of free gas below the hydrate stability zone as well.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.464-466
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• 2014

We investigate the effect of hydrogen on adsorption of hydrocarbon molecules on graphene with density functional theory (DFT) calculations. In this study, we calculate the binding energies of hydrogen molecule, carbon atom and other hydrocarbon fragments such as CHx (x=1, 2, 3, 4) on graphene to find the most stable adsorption site. Then, to study the effect of hydrogen, we investigate the adsorption of hydrocarbon fragments in the presence of hydrogen atoms on graphene.

• 한국화재소방학회논문지
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• 제10권2호
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• pp.13-19
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• 1996

An estimation methodology, based on statistics and numerical method, has been developed for estimating the upper explosive limits(UEL) of paraffinic and olefinic hydrocarbon compounds. With proposed method, the UEL has been calculated for 24 paraffinic and 10 olefinic hydrocarbon compounds. The estimated the UEL agree with the experimental values within a few percent. A comparisond with four other methods avaiable in the literature are also presented. It is hoped eventually that this method will permit estimation of the UEL with improved accuracy and broader application for other compounds.