• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1873-1875
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• 1999

The effects of electrode and matrix in the PAFC were investigated using AC-impedance spectroscopy. The performance of PAFC was determined by changing external electronic load. AC impedance measurement was carried out as functions of phosphoric acid impregnation temperature. operating temperature and matrix coating method using various cathodes ; 20%Pt/C, 20%Pt-Ni/C, 20%Pt-Co-Ni/C, 10%Pt-Fe-Co/C, and 20%Pt-Fe-Co/C From the analysis of measured impedance data, the interfacial resistance decreased with increasing operating temperature. and with decreasing impregnation temperature. As compared with the alloy catalysts, Pt catalyst showed a lower interfacial resistance. This consist with the cell performance.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.85.2-85.2
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• 2010

There is widespread effort to develop polymer membranes in place of Nafion for high temperature polymer electrolyte membrane fuel cell(PEMFC). In our study, SiO2 membranes are arranged by electrospinning method. For impregnation solution, the modified sulfonated poly(ether ether ketone)(SPEEK) polymer is prepared from sulfonation, sulfochlorination, partial reduction and lithiation reaction. The modified polymer is cross-linked with 1,4-diiodobetane in NMP solvent and then blended with Heteropoly acid(HPA). The characterization of membranes is confimed by FT-IR, Thermogravimetry(TGA), water uptake test and single cell performance test for PEMFC, etc. The composite membrane shows satisfactory thermal and mechanical properties. Beside, The membrane exhibits good ion exchange capacity and high proton conductivity. As a result, The composite membrane is promising as an alternative membrane in high temperature PEMFC.

• Journal of Pharmaceutical Investigation
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• v.21 no.1
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• pp.51-55
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• 1991

Porous spheres composed of natural waxes and inorganic materials containing vitamin E acetate as a drug were prepared by impregnation method. Furthermore, the amount of vitamin E acetate entrapped in the spheres and the release rate of vitamin E acetate from the spheres were studied. The impregnation of vitamin E acetate was carried out by dipping the spheres in vitamin E acetate solutions. Entrapment mechanism of vitamin E acetate could be expressed in terms of Langmuir's adsorption isotherm. The amount of vitamin E acetate entrapped in porous spheres was influenced by the structure and concentration of the polymer used in vitamin E acetate solutions, and the concentration of vitamin E acetate. Release characteristics of vitamin E acetate from the spheres were investigated by withdrawing samples periodically and analyzing them by spectrophotomer.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.199-208
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• 2000

In this study we investigated on the possibility of platinum and silver catalysts as de-NOx catalyst for activity test of supported metal oxide catalysts. the study was performed with the change of amount of metal and support types. The catalyst was prepared the activity of alumina supported silver catalyst produced by dry and wet impregnation method respectively and the resistance of sulfur for optimum supported silver catalyst,. As a result the activity of alumina supported platinum catalyst was showed at low temperature region but the case of silver catalyst activated at high temperature region. So we finally chose alumina supported silver catalyst as de-NOx target catalyst because alumina supported catalyst showed higher activity than alumina supported platinum catalyst.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.311-316
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• 2010

According to increase of combined cycle power generation, the manufacturing market of gas turbine generator has become more competitive, so there is high pressure on the manufacturer to reduce generator price. Global VPI(vacuum pressure impregnation) method is effective to save the production cost and time for manufacturing stator windings, but it has an abrasion problem by vibration between stator windings and slots. This paper presents the insulation breakdown case, which is for VPI type generator during high voltage insulation tests, and also shows the cause analysis, repair works as well as reliability test. the purpose of this paper is to understand the insulation properties of VPI type generator and to know prevention of insulation weakness.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.77-80
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• 2004

The purpose of this study was to examine effects of combustion retardation for paper filter impregnated metal salts by measurement of extinguishing concentration, CO concentration, and limiting oxygen index(LOI, ASTM D 2863). And thermal stability analysis using DSC was carried out. In case of extinguishing concentration, $NH_4H_2PO_4$ showed excellent effect of combustion retardation. The result of LOI measurement showed that metal salts possessed good effect of combustion retardation. And thermal analysis using DSC showed that these metal salts possessed thermal stability. In case of CO concentration, CO concentration was increasing because of imperfect combustion process due to combustion retardation effect of metal salts.

• Journal of Conservation Science
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• v.27 no.4
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• pp.395-401
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• 2011

After pressurized impregnation treatment, which has been proposed as an effective conservation method for stone cultural property, was executed with methyl metacrylate (MMA), MMA-butyl acrylate (PMB73) mixture and MMA-vinyl trimethoxy silane (PMV5) co-monomer mixture, the physical-chemical properties on the sand stone and the granite impregnated were evaluated. Compared to the case of granite, the impregnation ratios of sand stone showed larger values in the range of 3.2 to 3.7 wt% and these were increased up to 32% when the decompression process was applied to autoclave. The physical properties of sand stone such as anti-moisture property, flexural strength, impact property and ultrasonic velocity were also higher values than those of granite, which can be interpreted by high impregnation ratio resulted in many void within sand stone. The impact failure energy was 1.22 J for PMMA, 1.84 J for PMB73, and 2.8 J for PMV5, respectively. Since the inorganic affinity of treatment agent is more effective than the molecular structure of acrylic agent, PMV5 improved inorganic property indicates the optimum impact property.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.472-478
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• 2023

In this study, the acetaldehyde removal characteristics of activated carbon (AC) for air purifier filters were investigated using metal catalysts-impregnation and functional group-modification method. The AC with a high specific surface area(1700 m²/g) and micropores was prepared by KOH activation of coconut charcoal and the efficiency of catalyst and functional group immobilization was examined by varying the drying conditions within the pores after immersion. The physical properties of the prepared activated carbon were analyzed by BET, ICP, EA, and FT-IR, and the acetaldehyde adsorption performances were investigated using gas chromatography (GC) at various impregnation and modified conditions. As the concentration of impregnation solution increased, the amount of impregnated metal catalysts increased, while the specific surface area showed a decreasing trend. The adsorption tests of the metal catalyst-impregnated and functional group-modified activated carbons revealed that excellent adsorption performance in compositions MgO10@AC, CaO10@AC, EU10@AC, and H-U3N1@AC, respectively. The MgO10@AC, which showed the highest adsorption performance, had a breakthrough time of 533.8 minutes and adsorption capacity of 57.4 mg/g for acetaldehyde adsorption. It was found that the nano-sized MgO catalyst on the activated carbon improved the adsorption performance by interacting with carbonyl groups of acetaldehyde.

• Journal of Conservation Science
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• v.24
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• pp.57-66
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• 2008

It is reported that excavated carbonized wooden objects tend to have more peeling and deformation stemming from the coexisting of different types of parts of objects. However, there is little research results on this. In this experiment, the sugar alcohol method was used and then compared with the results of the PEG4000 method which widely uses. This research targets: prediction of strength by weight increase, investigation of the dimensional stabilization effects by measuring the rate of shrinkage change, condition of drug penetration and change of wood texture by using a scanning electron microscope. As the results, the PEG4000 method needs a phased approach over 80% impregnation. On the other hand, the S A method remains steady from over 40% impregnation. The Deformation of carbonized wooden objects used in this experiment is considered as the phenomenon by shrinkage of non-carbonized parts. The PEG4000 method is verified the shrinkage in the samples treated with 20%, 40% and 60%; the S A method is verified the shrinkage in the samples treated with 20%.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.249-256
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• 2011

In this study, the Ni-based catalysts for the production of synthetic natural gas were prepared by various preparation methods such as the co-precipitation, precipitation, impregnation and physical mixing methods. The ranges of the reaction conditions were the temperatures of 250~$350^{\circ}C$, $H_2$/CO mole ratio of 3.0, the pressures of 1 atm and the space velocity of 20000 $ml/g_{-cat{\cdot}}{\cdot}h$. It was found that the catalyst prepared by precipitation method had higher CO conversion than the catalyst prepared by co-precipitation method. While the catalyst prepared by precipitation method had the formation of NiO structure, the catalyst prepared by co-precipitation method had the formation of $NiAl_2O_4$ structure. It was confirmed that Ni-based catalyst prepared by the physical mixing method had the lowest CO conversion because it was deactivated by the production of $Ni_3C$ during the methanation. As a result, it was shown clearly that Ni-based catalysts prepared by impregnation method expressed the highest catalytic activity in CO methanation.