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무전극형광램프 ULTRA 150W용 EMI 필터에 대한 연구
박석인(S. Park),한수빈(S. Han),유승원(S. Yu),송유진(Y Song),정학근(H. Jeong),정봉만(B Jung) 한국조명·전기설비학회 2006 한국조명·전기설비학회 학술대회논문집 Vol.2006 No.5월
Offline switching power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp"s ballasts have AC/DC flyback converter, so we must control the EMI emissions.
[論文] 흡배기 관내의 비정상 유동을 고려한 4사이클, 4기통 전기·점화 기관의 성능 예측에 관한 연구
박성서(S.S.Park),김응서(E.S.Kim) 한국자동차공학회 1991 오토저널 Vol.13 No.6
In this study, the analytic investigation of the unsteady flow in the intake and exhaust pipes has been carried out using the method of characteristics in one direction to predict volumetric efficiency. Based on the calculated volumetric efficiency, three zone predictive analysis using Wiebe function was applied to predict the engine performance and the results were compared with experiment. Mixture in the cylinder is subdivided into three zones during combustion process in this analysis; adiabatic core zone, thermal boundary layer zone and unburned zone. In each zone, pressure, temperature and gas composition have been calculated.<br/> In conclusion, it is possible to take account of the intake and exhaust pipe tuning effect in predicting the engine performance, by the analytic solution of the unsteady flow in the pipes, and comparison of prediction with experimental results shows a good agreement on the pressure variation in the intake and exhaust pipes which has a direct influence on the volumetric efficiency and performance of the engine.
교차가새형 선행 안전난간을 적용한 시스템비계의 구조 성능 평가
박주동,이현섭,신우승,권용준,박순응,양승수,정기효,Park, J.D.,Lee, H.S.,Shin, W.S.,Kwon, Y.J.,Park, S.E.,Yang, S.S.,Jung, K. 한국안전학회 2020 한국안전학회지 Vol.35 No.5
In domestic construction sites, when installing steel pipe scaffolding and system scaffolding, the guardrails are installed after the installation of the work platforms. This conventional guardrail system (CGS) is always exposed to the risk of falls because the safety railing is installed later. In order to prevent fall disasters during erecting and dismantling scaffolds, it is necessary to introduce the advanced guardrail system (AGS) which installs railings in advance of climbing onto a work platform. For the introduction of the AGS, the structural performance of the system scaffolding applying the CGS and the AGS was compared and evaluated. The structural analysis of the system scaffold (height: 31 m and width: 27.4 m) with AGS confirmed that structural safety was ensured because the maximum stress of each element of the system scaffolding satisfies the allowable stress of each element. As a result of performance comparison of CGS and AGS for each element, the combined stress ratio of vertical posts in AGS was 6.4% lower than that of CGS. In addition, in the case of ledger and transom, the combined stress ratios of AGS and CGS were almost the same. The compression test of the assembled system scaffolding (three-storied, 1 bay) showed that the AGS had better performance than the CGS by 9.7% (8.91 kN). The cross bracing exceeds the limit on slenderness ratio of codes for structural steel design. But the safety factor for the compressive load of the cross bracing was evaluated as meeting the design criteria by securing 3 or more. In actual experiments, it was confirmed that brace buckling did not occur even though the overall scaffold was buckled. Therefore, in the case of temporary structures, it was proposed to revise the standards for limiting on slenderness ratio of secondary or auxiliary elements to recommendations. This study can be used as basic data for the introduction of AGS for installing guardrails in advance at domestic construction sites.