• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1808-1809
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• 2011

신재생 에너지 발전용 연료인 바이오가스는 자체로는 가스터빈 발전기의 연료로 사용할 수 없으므로 이를 연료화하기 위한 설비로 각종 화학처리설비와 전기설비, 제어설비가 필요하다. 본 논문에서는 국내기술로는 최초로 개발 중인 5MW급 가스터빈용 바이오가스 연료화 설비의 구성 및 기능, 이를 운전하기 위한 전기설비와 제어설비에 대한 내용을 간략히 기술하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.876-883
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• 2007

The magnetic flux leakage(MFL) type nondestructive testing(NDT) method is widely used to detect corrosion, defects and mechanical deformation of the underground gas pipelines. The object pipeline is magnetically saturated by the magnetic system with permanent magnet and yokes. Hall sensors detect the leakage fields in the region of the defect. The defects are sometimes occurred in group. The accuracy of the detecting signals in this defect cluster become lowered because of the complexity of the defect cluster. In this paper, the effects of the multi -defects are analyzed. The detecting signals are computed by 3-dimensional finite element method and compared with real measurement. The results say that, rather than the size of the defects, the effects of the relative position of the multi-defects are very important on the detecting signals.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.6-11
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• 2013

In this paper, the temperature characteristics of mold transformer for the distribution power system have been analyzed by using computational fluid dynamics(CFD). The model has been modeled by coil, cores, insulating materials and frames about 3MVA grade mold transformer and analyzed the temperature distribution of the structure with a heat fluid. The fluid, which is incompressible ideal gas, is analyzed as a turbulent flow phenomenon on the assumption that it is natural cooling of transformer cooling system. Through this study, by examining the temperature distribution and hot-spot of the structure field of the mold transformer, cooling design and temperature distribution information, which are demanded for designing are estimated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.228-236
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• 2011

The analysis of the performance and the internal flow according to various numerical models used for the interior ballistics has been conducted. The internal flow has been mainly affected by the drag model. As results, oscillations of the pressure differences between the breech and the shot base has been reduced with a deceased drag of the propellant. The major performance of the interior ballistics has no relation to the models using Nusselt number for heat transfer coefficient. The negative pressure difference without the heat transfer of the propellant has not been shown.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.139-153
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• 2011

In this paper we develop a fully anisotropic pressure and temperature dependent model to investigate the effect of the microstructure on the shock response of ${\beta}$-HMX molecular single and polycrystals. This micromechanics-based model can account for crystal orientation as well as crystallographic twinning and slip during deformation and has been calibrated using existing gas gun data. We observe that due to the high degree of anisotropy of these polycrystals, certain orientations are more favorable for plastic deformation - and therefore defect and dislocation generation - than others. Loading along these directions results in highly localized deformation and temperature fields. This observation confirms that most of the temperature rise during high rates of loading is due to plastic deformation or dislocation pile up at microscale and not due to volumetric changes.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.99-105
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• 2001

For the design of selective catalytic reactors of NOx by $NH_3$, engineering approach can be performed to determine the reactor shape, mixing device and $NH_3$ injection system. This study shows the optimization of guide vanes to improve the flow pattern near the catalyst layer of SCR in a untility boiler. By varying their spacings and shapes, flow performance of guide vanes was analyzed to achieve an uniform velocity distribution which increases the NOx convesion efficiency, and a flow direction normal to the layer which minimises the erosion by the dust in the flue gas. Including these results, experimental and numerical studies for the SCR design were discussed.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.339-340
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• 2012

The purpose of this study is to analyse, the basic parameters through experimentally and with CFD modelling, internal recirculation of the flameless combustion of natural gas. The test rig is made up of a vertical combustion chamber of circle cross section. The inner dimensions of the chamber are $0.2m{\times}1m$ (diameter x height). And CFD simulations of the combustion chamber have been performed using FLUENT 14.0. Some results of this study present the basic parameters and data of flameless combustion.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.544-546
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• 2008

An improved dual-path energy recovery circuit (ERC) using a current source and a voltage source for plasma display panel (PDP) is proposed. The proposed ERC uses the voltage source to charge a panel and the current source to discharge the panel. Thus, the proposed circuit can make the panel charge to $V_S$ and discharge to 0V, fully and it is possible to achieve zero voltage switching (ZVS) of all switches in H-bridge inverter and zero current switching (ZCS) of all switches in the ERC. Moreover, it has less conduction and switching loss in ERC devices by the dual energy recovery paths for charging and discharging the panel. Furthermore, it has features of canceling the gas discharge current, high performance and the low cost ERC components. The operation principle and features of the proposed ERC are presented in detail and verified with 42-inch SD PDP.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.964-967
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• 2002

The effectiveness of silicon nitride SiNx surface passivation is investigated and quantified. This study adopted single-layer antireflection (SLAR) coating of SiNx for efficiency improvement of solar cell. The silicon nitride films were deposited by means of plasma enhanced chemical vapor deposition (PECVD) in planar coil reactor. The process gases used were pure ammonia and a mixture of silane and helium. The thickness and the refractive index on the films were measured by ellipsometry and chemical bonds were determined by using an FT-IR equipment. This films obtained were analyzed in term of hydrogen content, refractive index for gas flow ratio $(NH_3/SiH_4)$, and efficiency of solar cell. The polycrystalline silicon solar cells passivated by silicon nitride shows efficiency above 12.8%.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.485-486
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• 2008

The network structure of $SnO_2$ nanowires was fabricated on the electrodes by a simple thermal evaporation process from Sn metal powders and oxygen gas. The diameter of the nanowires was $20\;{\sim}\;60\;nm$ depending on the processing conditions. The operating temperature of the sensor could be decreased down below $50^{\circ}C$ by controlling the properties of the nanowires and the structures of the electrodes. The sensitivities were $10\;{\sim}\;15$ when the $NO_2$ concentrations were $10\;{\sim}\;50\;ppm$ at the operating temperature of $50^{\circ}C$.