• 공업화학
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• 제5권4호
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• pp.706-713
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• 1994

$45^{\circ}C$와 $65^{\circ}C$의 등온하에서 MTBE-methanol, MTBE-n-heptane, methanol-n-heptane 각 이성분계에 대한 등온 기액 평형 데이타를 head space gas chromatography(H.S.G.C.)를 이용해서 측정하였다. 이들중에 MTBE-methanol계와 methanol-n-heptane계에서 최소공비점이 발견되었으며, 특히 methanol-n-heptane계에서는 불용영역의 존재로 인한 불균일 최소공비점을 나타내었다. 각각의 실험 데이타들은 과잉 Gibbs 에너지 모델에 합치시켜서 그 상관관계를 알아보았으며, Redlich-Kister의 적분법에 의한 열역학적 일치성 시험도 수행하였다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2005년도 추계학술발표회 논문집
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• pp.83-87
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• 2005

The kinetics of the direct synthesis of DME was studied under different conditions over a temperature range of $220\~280^{\circ}C$, syngas ratio $1.2\~ 3.0$ All experiment were carried out over hybrid catalyst, composed to a methanol synthesis catalyst (Cu/ZnO/$Al_2O_3$) and a dehydration Catalyst ($\gamma$-Al_2O_3$) The observed reaction rate qualitatively follows a Langmiur-Hinshellwood type of reaction mechanism. Such a mechanism is considered with three reaction, methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol and water, individual reaction rate was determined

• 열처리공학회지
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• 제23권5호
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• pp.245-248
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• 2010

Sn doped $In_2O_3$ (ITO) and ITO/Ni/ITO (INI) multilayer films were deposited on the glass substrates with a reactive magnetron sputtering system without intentional substrate heating and then the influence of the Ni interlayer on the methanol gas sensitivity of ITO and INI film sensors were investigated. Although both ITO and INI film sensors have the same thickness of 100 nm, INI sensors have a sandwich structure of ITO 50 nm/Ni 5 nm/ITO 45 nm. The changes in the gas sensitivity of the film sensors caused by methanol gas ranging from 100 to 1000 ppm were measured. It is observed that the INI film sensors show the higher sensitivity than that of the ITO single layer sensors. Finally, it can be concluded that the INI film sensor have the potential to be used as improved methanol gas sensors.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2442-2444
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• 2007

CO adsorbates on the surface of Pt supported on carbon catalysts (Pt/C) were investigated by CO stripping voltammetry. Three types of CO adsorbed samples were prepared: by methanol dehydrogenation only (COm), by CO gas bubbling only (COg), and by methanol dehydrogenation followed by CO gas bubbling (COm+g). Our coverage data show that CO gas can be adsorbed on Pt/C catalyst already saturated with CO adsorbates by methanol dehydrogenation. The COm+g sample showed the properties of both COm as well as COg samples in terms of the potential although the CO adsorbed by dehydrogenation was completely exchanged with CO in the electrolyte solution. Therefore, the oxidation pathways of CO on Pt/C were observed to depend on the initial adsorption conditions of CO more strongly than on the CO coverage. Our results imply that an initial CO poisoning condition in fuel cell operation is an important factor to determine the difficulty in removing the adsorbed CO and confirm that the properties of the adsorbed CO do not change even with chemical replacement with CO in different conditions. In addition, our results indicate a low CO surface mobility on the Pt in an electrolyte solution.

• Transactions on Electrical and Electronic Materials
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• 제11권2호
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• pp.77-80
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• 2010

Indium tin oxide (ITO) films with a 5 nm thick Au interlayer were prepared on glass substrates. The effects of the Au interlayer on the gas sensitivity for detecting methanol vapors were investigated at room temperature. The conductivity of the film sensor increased upon exposure to methanol vapor and the sensitivity also increased proportionally with the methanol vapor concentration. In terms of the sensitivity measurements, the ITO film sensor with an Au interlayer shows a higher sensitivity than that of the conventional ITO film sensor. This approach is promising in gaining improvement in the performance of ITO gas sensors used for the detection of methanol vapor at room temperature.

• 한국가스학회지
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• 제8권4호
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• pp.23-29
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• 2004

이 연구는 가스 하이드레이트 제조시 첨가제로 아세톤, 디메틸부탄, 폴리비닐알코올, 메탄올, 에틸렌글리콜등의 다양한 화학약품을 이용하여 하이드레이트 생성 특성을 변화시키는 것이다. 아세톤, 디메틸부탄, 폴리비닐 알코올을 첨가하여 하이드레이트를 제조한 경우 가스저장능력은 순수한 물로 하이드레이트를 제조한 경우보다 증가하였다. 이중 폴리비닐알코올은 다른 첨가제보다 더 많은 가스를 저장하므로 가장 유용한 생성 촉진제로 판단된다. 사용된 첨가제중 메탄올과 에틸렌글리콜은 생성 억제제의 특성을 나타내었고 에틸렌글리콜보다 메탄올이 조금 더 낮은 가스 저장능력을 나타내어 유용한 생성 억제제로 판단된다. 그러나 생성 억제제로서의 메탄올과 에틸렌글리콜이 낮은 농도인 경우 가스 저장능력이 순수한 물보다 증가하는 생성 촉진제의 특성을 보여준다.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.717-724
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• 2016

Methane (CH₄) is the most abundant component in natural gas. To reduce its harmful environmental effect as a greenhouse gas, CH₄ can be utilized as a low-cost feed for the synthesis of methanol by methanotrophs. In this study, several methanotrophs were examined for their ability to produce methanol from CH₄; including Methylocella silvestris, Methylocystis bryophila, Methyloferula stellata, and Methylomonas methanica. Among these methanotrophs, M. bryophila exhibited the highest methanol production. The optimum process parameters aided in significant enhancement of methanol production up to 4.63 mM. Maximum methanol production was observed at pH 6.8, 30℃, 175 rpm, 100 mM phosphate buffer, 50 mM MgCl₂ as a methanol dehydrogenase inhibitor, 50% CH₄ concentration, 24 h of incubation, and 9 mg of dry cell mass ml^-1 inoculum load, respectively. Optimization of the process parameters, screening of methanol dehydrogenase inhibitors, and supplementation with formate resulted in significant improvements in methanol production using M. bryophila. This report suggests, for the first time, the potential of using M. bryophila for industrial methanol production from CH₄.

• 한국응용과학기술학회지
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• 제4권1호
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• pp.9-18
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• 1987

The effects of procedures for preparation of fatty acid methyl esters for gas chromatography were investigated. A quantitative comparison of four procedures for the preparation of the fatty acid methyl esters from Korean sesame seed lipids which can be representative of fatty acid ranges of Korean vegetable oils has been made. The procedures employed were $BF_3$-methanol, HCI-methanol, sodium methoxide-methanol, and tetramethylammonium hydroxide-methanol. Twelve fatty acids ranged from 14:0 to 24:0 were identified in the lipids from Korean white and black sesame seeds. All four procedures gave similar results for the fatty acids, 16:0, 18:0, 18:1, 18:2, and 18:3 present in the range of $1{\sim}44%$ but only in the HCI-methanol procedure, the fatty acids, 16:1, 20:0, 22:0, 24:0 present in the range of $0.02{\sim}1%$ showed the lowest values. When using tetramethylammonium hydroxide-methanol procedure for determination of total fatty acid composition from white and black sesame seed lipids, unsaponifiable matters including sesamol, sesamolin and sesamin present in the seed lipids are not removed from the resulting reaction mixture. Thus the transesterification mixture is used without further treatment for injection into the gas chromatography. However, the gas chromatographic analysis of the transesterification mixture showed that the unsaponifiable matters had no effect on the fatty acid composition of the seed lipids. From the results, it appears that the $BF_3$-methanol, sodium methoxide-methanol and tetramethylammonium hydroxide-methanol procedures can be used to prepare fatty acid methyl esters from Korean vegetable oils. Among the methods, the tetramethylammonium hydroxide-methanol procedure, which give total fatty acid composition, glyceride fatty acid composition and composition of free fatty acids present, appears to be a simple, convenient and quantitative procedure and applicable to samples containing broad ranges of fatty acids.

• 산업기술연구
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• 제17권
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• pp.339-344
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• 1997

DOHC gasoline engine(4-cylinder in line type, 1600cc) is modified for the experiment to develope an alternative fuel. The modified engine is tested with the various combination of gasoline and methanol. Pollutant emissions of CO and HC are measured at the end of exhaust manifold. The concentration of CO and HC in exhaust gas is greatly reduced with the increase of coolant temperature of engine. HC concentration is reduced until methanol content reaches to thirty percent and then increased with the volumetric percentage of methanol in fuel. On the other hand, the concentration of CO is reduced as the methanol centent is increased up to 20 percent and then it becomes constant even though the methanol content is raised. The effect of engine RPM on the HC and CO exhaust is investigated. HC concentration is reduced as the engine RPM is increased but the typical trends of variation are not found in the measured value of CO concentrations.

• 한국수소및신에너지학회논문집
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• 제15권4호
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• pp.283-290
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• 2004

The single-step process for conversion of syngas to DME give higher conversion than the syngas-to-methanol process. This arises because of a synergy among the three simultaneous reaction, methanol synthesis, methanol dehydration and water gas shift reaction, in the process. we would find the optimal condition of the process which these advantages. The optimal condition of DME synthesis reaction over a commercial $Cu/Zn/Al_2O_3$ catalyst and Hybrid catalyst in a fixed bed reactor. The syngas-to-dimethyl ether conversion was examined on various reaction condition (Temperature 473~553K, $H_2/CO$ ratio 1~3, Pressure 30'50atm, GHSV 1000~4000).