• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.759-761
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• 2002

A new method for the preparation of copper activated zinc sulfide phosphors by combustion method has been proposed. Copper nitrate was decomposed with an organic fuel to give fine sized particles in presence of alkali metal halides at low temperature than the conventional synthesis. Organic compound also acted as fuel at 500 $^{\circ}C$ with rapid heating. The phosphors thus obtained were then heated at 900 $^{\circ}C$ in an inert atmosphere for 2-5 hrs to get better luminescent properties.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.163-177
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• 2006

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.458-458
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• 2012

Fuel Cell is used stacking metal or polymer substrate. This hydro property of substrate surface is very important. Usually, surface property is hydrophilic. The surface oxidation of SUS is investigated through plasma treatments with an atmospheric-pressure dielectric barrier discharge (DBD) for increasing hydrophilic property. The plasma process makes an experiment under various operating conditions of the DBD, which operating conditions are treatment time, plasma gas mixture ratio, the plasma source supply frequency. Two kinds of SUS substrate, SUS-304 and SUS 316L, were used. Discharge frequency has a crucial impact on equipment performance and gas treatment. After the plasma treatment of a SUS plate, highly improved wettability was noted. But, when high oxygen supply, the substrate damaged seriously.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.645-650
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• 1997

An oxide fuel small size core (1200 MWt) was analyzed in comparison with a large size core (3600 MWt) in order to evaluate the size effects on transient safety performances of liquid-metal reactors (LMRs). in the first part of the study, main static safety parameters (i.e., Doppler coefficient, sodium void effect, etc.) of the two cores were characterized, and the second part of the study was focused on the dynamic behavior of the cores in two representative transient events: the unprotected loss-of-flow(ULOF) and the unprotected transient overpower (UTOP). Margins to fuel molting and sodium boiling have been evaluated for these representative transients. Results show that the small core has a generally better or equivalent level of safety performances during these events.

• Ceramist
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• v.22 no.2
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• pp.189-197
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• 2019

Direct methanol fuel cells (DMFCs) have found a wide variety of commercial applications such as portable computer and mobile phone. In a fuel cell, the catalysts have an important role and durability and efficiency are determined by the ability of the catalyst. The activity of the catalyst is determined by the structure and shape control of the nanoparticles and the dispersion of the nanoparticles and application system. The surface energy of nanoparticles determines the activity by shape control and the nanostructure is determined by the ratio of bi- and tri-metals in the alloy and core-shell. The dispersion of nanoparticles depends on the type of support such as carbon, graphen and metal oxide. In addition, a hybrid system using both optical and electrochemical device has been developed recently.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.741-749
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• 1994

The planar solid oxide fuel cell(SOFC) contains several ceramic materials depending on its structure and has rdfractory metal parts for manifolds, shrouds and current leads. Among ceramic materials for planar SOFC, joining of lanthanum chromite separator and yttria stabilized zirconia(YSZ) electoyte in planar SOFC stack to give strong gas tight seals is necessary for satisfactory operation and high performance. Nevertheless, for planar SOFC/sub s/, how to seal the cell stack and gas manifold remains as one of the unsolved problems. Therefore, in this study. we investigated the joining of sintered lanthanum chromite and YSZ pellets using unsintered lanthanum chromite green films as sealent. Scanning electron microscopy(SEM) and energy dispersive X-ray analysis(EDX) revealed that Ca in the sealing material diffused and dissolved into YSZ and sintered lanthanum chromite, and unsintered lanthanum chromite green films reacted with YSZ to from a new phase at the interface. Also, the densification of unsintered lanthanum chromite green films was inpeded by the Ca migration.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.184-186
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• 2012

In this work, 3-dimensional, non-isothermal numerical simulation was performed to analyse the effects of contact resistance and electric conductivity of GDL on the fuel cell performance. For numerical simulation contact resistance of Carbon and Stainless steel was measured. The simulation results reveal that 10 times change of electric conductivity leads only 6.5% decrease of PEMFC performance. But stainless steel which has high contact resistance decrease fuel cell performance over 25% at a high current density region than carbon. This results show that suitable Surface treatment technology is needed for metal bipolar plate, especially stainless steel.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.712-718
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• 2016

Platinum catalysts supported on the mesoporous material synthesized from Y zeolite were applied to synthesis of jet-fuel through n-octadecane hydroupgrading. The mesoporous aluminosolicate, $MMZ_{HY}$ was synthesized using Y zeolite as its framework source. The effect of the addition of Mg to $Pt/MMZ_{HY}$ catalyst for n-octadecane hydroupgrading was investigated. Catalyst characterization was performed with X-ray diffraction, $N_2$ adsorption, temperature-programmed reduction in hydrogen flow, temperature-programmed desorption of ammonia, and infrared spectroscopy of adsorbed pyridine. The high yield of jet-fuel over the $PtMg(2.0)/MMZ_{HY}$ can be attributed not only to the higher dispersion of Pt metal and higher reducibility, but also the higher amount of acid sites and higher strength of acid sites. The selectivity to iso-paraffin in the jet-fuel fraction could be reached above 80% over the optimized $PtMg/MMZ_{HY}$ catalyst.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.663-670
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• 2005

DIN CK35 (JIS S35CK) steels have been used as a material in fuel pump blocks for marine engines. Failures in the inner surface of a drilling hole, due to the initiation of fatigue cracks have been frequently reported. However, the mechanism initiating these cracks and growths has not been clearly diagnosed yet. This study was conducted using a scraped fuel pump block, containing an initiated fatigue crack in the inner surface of a drilling hole. Initially, the cracks and fractured surfaces inside the block were investigated using an optical microscope and a SEM (Scanning Electron Microscope). In addition, microstructure observation, fatigue life test and fatigue crack growth test were performed using a specimen, which was taken from the same block. Results from these tests are summarized as follows; (1) The early crack in the block was supposed to occur inside the inner surface of the drilling hole. (2) The fatigue endurance of this material was about 330 Mpa. (3) The early crack was generated in the cavitations created by the breakdown of a big inclusion, or separation between the big inclusion and the base metal, in which the fundamental ingredients of the inclusion were C, 5, and Mn. (4) In order to prevent these types of failures, the suppression of inclusions inflow by improving the casting process, formation of fine inclusions by applying a heat treatment process, and coating of the surface of the drilling hole were required.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.220.2-220.2
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• 2011

Biodiesel and biodiesel blend fuel are receiving increasing attention as alternative fuels for diesel engines without substantial modifications. Biodiesel fuels and blending have been widely studied and applied in diesel engine because of biodiesel's lower sulfur, lower aromatic hydrocarbon and higher oxygen content. Biodiesels have the potential to be oxidized in different condition. It has reported that oxidation deterioration of biodiesel is different in the condition of storage and oxidation causes chemical property change of methyl esters. Sunlight intensity, temperature, material of container and contact surface with oxygen are key dominant factors accelerating oxidation deterioration. In this study, we chose temperature among key oxidation conditions and metal container filled with biodiesel was heated at about $110^{\circ}C$ for 10 days in order to accelerate oxidation deterioration. To better understand the effect of biodiesel blends on emission, steady state tests were conducted on a heavy duty diesel engine. The engine was fueled with Ultra Low Sulphur Diesel(ULSD), a blend of 10% and 20%(BD10, BD20) on volumetric basis, equipped with a common rail direct injection system and turbocharger, lives up to the requirements of EURO 3. The experimental results show that the blend fuel of normal biodiesel with BD10 and BD20 increased NOx. The result of PM was similar to diesel fuel on BD10, but the result of PM on BD20 was increased about 63% more than its of diesel. The blend fuel of Oxidation biodiesel with BD10 and BD20 increased NOx as the results of normal biodiesel. But PM was all increased on BD10 and BD20. Especially THC was extremely increased when test fuel contains biodiesel about 140% more than its of diesel. Through this study, we knew that oxidation deterioration of biodiesel affects emission of diesel engine.