• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.103-110
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• 2019

Cu-Zn-Al catalysts were prepared via co-precipitation method for low-temperature water-gas shift (LT-WGS) reaction under practical reaction condition. Aging time was systematically changed to find optimum point for LT-WGS under practical condition. The Cu-Zn-Al catalyst aged for 72 hours showed the highest CO conversion within low-temperature range as well as very stable catalytic activity for 200 hours despite the practical reaction condition.

• Advances in Energy Research
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• v.8 no.4
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• pp.265-273
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• 2022

In this study, a product gas yield and carbon conversion were measured during the coal pyrolysis. The pyrolysis process occurred under two different atmospheres such as subcritical (45 bar, 10℃) and supercritical CO₂ condition (80 bar, 35℃). Under the same pressure (80 bar), the atmosphere temperature increased from 35℃ to 45℃ to further examine temperature effect on the pyrolysis at supercritical CO₂ condition. For all three cases, a power input supplied to heating wire placed below coal bed was controlled to make coal bed temperature constant. The phase change of CO₂ atmosphere and subsequent pyrolysis behaviors of coal bed were observed using high-resolution camcorder. The pressure and temperature in the reactor were controlled by a CO₂ pump and heater. Then, the coal bed was heated by wire heater to proceed the pyrolysis under supercritical CO₂ condition.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2015-2020
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• 2007

Diesel is an excellent candidate fuel for fuel cell applications due to its high hydrogen density and well-established infrastructure. But, it is hard to guarantee desirable performance of diesel reformer because diesel reforming has several problems such as sulfur poisoning of catalyst and carbon deposition. We have been focusing on diesel autothermal reforming(ATR) for substantial period. It is reported that ATR of diesel has several technical advantages such as relatively high efficiency and fuel conversion compared to steam reforming(SR) and partial oxidation(POX). In this paper, we investigate characteristics of diesel reforming under various ratios of reactants(oxygen to carbon ratio, steam to carbon ratio) for improvement of reforming performances(high reforming efficiency, high fuel conversion, low carbon deposition). We also exhibit calculated heat balance of autothermal reformer at each condition to help thermal management of SOFC system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.256-256
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• 2009

This paper presents a proper condition to achieve above 17 % conversion efficiency using PC1D simulator. Crystalline silicon wafer with thickness of $240{\mu}m$ was used as a starting material. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer. Among the investigated variables, we learn that 2nd doping concentration as a key factor to achieve conversion efficiency higher than 17 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.243-244
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• 2009

The $TiO_2$ nanofiber doped $TiO_2$ electrode area applied to dye-sensitized solar cells(DSSCs). The mixtures of $TiO_2$ nanofiber to $TiO_2$ photoelectrode has larger surface area than $TiO_2$ photoelectrode. In this research added 2.5, 5 and 10wt% $TiO_2$ nanofibers and the optimum condition of 5 wt% $TiO_2$ nanofiber's high surface area contributing the improvement of short-circuit photocurrent. The open-circuit voltage was 0.7V and solar energy conversion efficiency was 5.4%.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.129-133
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• 1997

Fine powder of $\alpha$-tricalcium phosphate, tetracalcium phosphate and dicalcium phosphate were mixed together to prepare self-setting cements which form hydroxyapatite, one of the well-known biocompatible materials, as the end of products of hydration. Hardening behaviour of the cements was examined at the temperature range of 37~$70^{\circ}C$ and 150~$250^{\circ}C$ under the normal and hydrothermal condition respectively. The conversion of cements into hydroxyapatite was significantly improved ast elevated temperature and the paste was strengtheed by interlocking of hydroxyapatite crystals, indicating that the strength is determined by microtexture rather the amount of conversion of cements into hydroxyapatite.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.1
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• pp.40-48
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• 2010

The purpose of the research is to develop the high performance solar chemical reactor for producing hydrogen using steam reforming reaction of methane. A specific shape chemical reactor is suggested : spiral type reactor. The reactor is installed on the dish-type solar thermal system of Inha University. The temperatures, $CH_4$ conversion rates, and Hz proportion are measured. At specific condition, $CH_4$ conversion rates of the spiral type reactor are about 91%, and Hz proportion are about 66%. The spiral type reactor gives reasonably good performance without any problems caused by highly concentrated solar radiation.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.7-12
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• 1994

A yeast strain secreting glucoamylase was transformed with an expression vector (pMS12) containing the promoter of yeast alcohol dehydrogenase I gene ADC1, mouse salivary $\alpha$-amylase cDNA, and a segment of yeast $21\mu m$ plasmid. The transformed strain could produce ethanol from starch (4%, w/v) through a direct one-step process with the conversion efficiency of 93.2%, during 5 days of fermentation, while the original, untransformed strain exhibited a conversion efficiency of 38.1% under the same condition. When the regulatory site of the ADC1 promoter region was removed, the production of ethanol increased to 29~37% in the presence of exogenous 3%(v/v) ethanol in the fermentation medium.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.64-68
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• 2005

Methane reforming processes to obtain hydrogen were investigated experimentally by using atmospheric plasma source. Among possible reforming processes, such as a $CO_2$ reforming(dry reforming), a partial oxidation (POx), a steam reforming(SR), and a steam reforming with oxygen(SRO or auto-thermal reforming), partial oxidation and the steam reforming with oxygen were considered. We choose a rotating arc plasma as an atmospheric plasma source, since it shows the best performances in our preliminary tests in terms of a methane conversion, a hydrogen production, and a power consumption. Then, the effects of a feeding flow-rate, an electrical power input to a plasma reaction, an $O_2/C$ ratio and a steam to carbon ratio in the case of SRO on the reforming characteristics were observed systematically. As results, at a certain condition almost 100% of methane conversion was obtained and we could achieve the same hydrogen production rate by consuming a half of electrical power which was used by the best results for other researchers.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.15-21
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• 2000

The catalytic hydroxylation of several cycloalkanes in dichloromethane have been investigated using In(Ⅲ)-, Tl(Ⅲ)-porphyrin complexes as a catalyst and NaClO, $NaClO_{2}$, $H_{2}O_{2}$ as a terminal oxidant. Porphyrins were TPP and ($F_{20}$)TPP (TPP = tetraphenylporphyrin) and substrates were cyclopentane, cyclohexane, cycloheptane and cyclooctane. The substrate conversion yield was discussed according to the substituent effect and hinderance effect of metalloporphyrin and the radius effect of non-redox metal ion. The conversion yield of cycloalkane followed the order of $ C_{5} $ < $ C_{6}$ < $ C_{7}$ = $ C_{8}$. In this experimental condition $NaClO_2$ was rather efficient terminal oxidant than NaClO and $H_{2}O_{2}$.