• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.355-363
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• 2010

High purity hydrogen, 97-99 vol.%, with CO at just ppm levels was obtained in a fixed bed of iron oxide employing the steam-iron cycle operation with reduction at 823K and oxidation in a steam-$N_2$ mixture at 773K TGA experiments indicated that temperature of the reduction step as well as its duration are important for preventing carbon build-up in iron and the intrusion of $CO_2$ into the hydrogen product. At a reduction temperature of 823K, oxide reduction by $H_2$ was considerably faster than reduction by CO. If the length of the reduction step exceeds optimal value, low levels of methane gas appeared in the off-gas. Furthermore, with longer durations of the reduction step and CO levels in the reducing gas greater than 10 vol.%, carbidization of the iron and/or carbon deposition in the bed exhibited the increasing pressure drop over the bed, eventually rendering the reactor inoperable. Reduction using a reducing gas containing 10 vol.% CO and a optimal reduction duration gave constant $H_2$ flow rates and off-gas composition over 10 redox reaction cycles.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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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.

• 한국표면공학회지
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• 제35권6호
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• pp.371-376
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• 2002

Steam turbine components of power generators are subjected to severe damages from the particle erosion by iron oxides (mainly $Fe_3$$O_4$) which are formed due to the oxidation of boiler tubes, causing high costs for maintaining and repairing. One of the practical ways to minimize the particle erosion is to apply the erosion resistant boride coating on the turbine components which is composed of boride apply. But the evaluation of its performance has not been carried out. A particle erosion tester, which can offer the erosion condition of steam turbine components, was developed to evaluate the performances of the boronized Cr/Mo alloy. The result showed that the boronized Cr/Mo alloy showed superior resistance to particle erosion to the bare Cr/Mo alloy in all test conditions.

• 한국세라믹학회지
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• 제26권3호
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• pp.381-389
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• 1989

Effects of annealing temperature, time, and atmospehre on the flow characteristics of Atmospheric Pressure Chemical Vapor Deposition-borophosphosilicate glass were investigated. Stable step coverage can be obtained by annealing the BPSG film at 90$0^{\circ}C$ for 30 minutes in N2 atmosphere, but further heat treatment isnot effective. Flow characteristics of the BPSG film was better in steam atmosphere than in N2 atmosphere, and the factors which cause it were analyzed. The concentration of boron in the BPSG film was measured pretty accurately by FTIR spectrum. Boron content in the BPSG film was reduced by annealing treatment. The decrement of boron was greater in steam atmosphere than in the N2 atmosphere. Also it was found from the FTIR spectroscopic analysis that PH3 inhibited the oxidation of B2H6.

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1323-1327
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• 2001

The catalyst Ni/MgO (Ni : 15 wt%) has been applied to methane reforming reactions, such as steam reforming of methane (SRM), partial oxidation of methane (POM), and oxy-steam reforming of methane (OSRM). It showed high activity and good stability in all the reforming reactions. Especially, it exhibited stable catalytic performance even in stoichiometric SRM (H2O/CH4 = 1). From TPR and H2 pulse chemisorption results, a strong interaction between NiO and MgO results in a high dispersion of Ni crystallite. Pulse reaction results revealed that both CH4 and O2 are activated on the surface of metallic Ni over the catalyst, and then surface carbon species react with adsorbed oxygen to produce CO.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.534-541
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• 2021

In this study, a novel microwave-matrix reformer was proposed to convert CH₄, which is a major component, to a high quality hydrogen energy. And to identify this performance, it was investigated for O₂/C ratio, steam feed amount and reformed gas recirculation which are affected for methane conversion and product gas yield. Through the parametric screening studies, optimal operating conditions were that O₂/C ratio, steam feed amount and recirculation rate were 1.1, 10 mL/min and 30 L/min. In this conditions, CH₄ conversion was 68.1%, H₂ selectivity 77.2 and H₂/CO ratio 2.62 which are possible applying SOFC stack for RPG (residential power generator).

• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.669-673
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• 2002

Ni catalyst (Ni: 15 wt%) supported on precalcined SiO2 has been investigated in reforming reactions of methane to synthesis gas. The catalyst exhibited fairly good activity and stability in partial oxidation of methane (POM), whereas it deactivated in steam reforming of methane (SRM). Pulse reaction results of CH4, O2, and CH4/O2 revealed that Ni/SiO2 has high capability to dissociate methane. The results also revealed that both CH4 and O2 are activated on the surface of metallic Ni, and then surface carbon species react with adsorbed oxygen to produce CO and CO2 depending on the bond strength of the oxygen species on the catalyst surface.

• 한국식품영양과학회지
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• 제23권2호
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• pp.238-243
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• 1994

Changes of lipid components in modified oleoresin during cooking at high temperature were investigated. In preparation of the modified oleoresin, dried red pepper was milled to 100 mesh of size particle and extracted oily compounds by reduced pressure steam distillation . The rest part was reextracted and concentrated and concentrated. The extracts were combined. The same volume of water and 4% of polyglycerol condensed ricinoleate (PGDR) were added to the combined extract, and emulsified to make oleresin red pepper. Non-polar lipid components were quantified 3 times higher in the oleoresin than polar lipid components . The components of non-polar lipd was mainly triglyceride comprising 75.8%. The level of phosphatidyl choline and phosphatidyl ethanolamine were 38.6and 26.1%, respectively. linoleic acid was distinctively abundant (63.1%) and followed by palmitic acid, oleic acid, linolenic acid and stearic acid in the oleoresin. Oxidation of lipid at high temperature was principally affected by temperature rather than oxygen existence . With the result of oxidation , palmitic acid and myristic acid increased, however, oleic acid, linoleic acid, and linolenic acid decreased.

• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1670-1679
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• 2006

The development of the oxidation, wear and corrosion resistant materials that could be used in severe environmental conditions is needed. The elementary technologies for surface modification include ion implantation and/or thin film coating. Furthermore, in order to develop ion implantation technique to the specimens with three-dimensional shapes, plasma-based ion implantation (PBII) techniques were investigated. As a result, it was found that the ion implantation and/or thin film coating used in this study were/was effective for improving the properties of materials, which include implantations of various kinds of ions into TiAl alloy, TiN films formed on surface of base material and coatings in high-temperature steam. The techniques proposed in this study provide useful information for all of the material systems required to use at elevated temperature. For the practical applications, several results will be presented along with laboratory test results.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2295-2303
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• 2021

To investigate wall-thinning impact on axial load resistance of Zircaloy-4 cladding rods after a LOCA transient, axial tensile samples have been machined on as-received tubes with reduced thicknesses between 370 and 580 ㎛. After high temperature oxidation under steam at 1200 ℃ with measured ECR ranging from 10 to 18% and water quenching, machined samples were axially loaded until fracture. These tests were modeled using a fracture mechanics approach developed in a previous study. Fracture stresses are rather well predicted. However, the slightly lower fracture stress observed for wall-thinned samples is not anticipated by this modeling approach. The results from this study confirm that characterizing the axial load resistance using semi-integral tests including the creep and burst phases was the best option to obtain accurate axial strengths describing accurately the influence of wall-thinning at burst region.