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초등학교 고학년 학생의 전두엽연합령 기능에 따른 보존논리 형성 정도
김영신(Young Shin Kim),나은미(Eun Mi Na),권용주(Yong Ju Kwon),정완호(Wan Ho Chung) 한국초등과학교육학회 2001 초등과학교육 Vol.20 No.1
The purpose of this study is to investigate the functions of prefrontal lobe on the formation of conservation scheme of elementary students. In this study, 107 students of 4th to 6th grades were selected from the elementary school in Seoul area. As to the research, 4 items for conservation logic test from GALT test sheet were used. The planning ability, inhibiting ability and reasoning ability were measured for the prefrontal lobe functions. About 30% of 4-6 grade students did not have volume conservation logic skills. The formation of conservations was not linear. Inhibiting ability was significantly different in level of conservation. And, conservation logic skills were significantly correlated with cognitive variables. Reasoning ability was significantly explained about 10% of the conservation logic in 4-6 grades.
AL6061과 PBT 재료의 인서트 사출공정조건에 따른 접합강도 특성 분석
정용준(Yong-Jun Jung),김영신(Young-Shin Kim),전의식(Euy-Sik Jeon) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.5
As a trend of lightening automobiles and electronic products, several studies are currently underway to replace parts of metals with resins. In particular, heterojunctions between metals and resins are now under the spotlight. This study aims to evaluate the variation in bonding strength with process conditions when the polybutylene terephthalate (PBT) polymer is bonded to a specimen of the lightweight 6061 aluminum alloy (AL6061). Conditions of the bonding surface of the AL6061 specimen, the temperature of the injection mold, and the content of the glass fiber were considered to be process variables. Bonded specimens were manufactured for different values of these variables. Bonding strength tests were then performed on these specimens and variations were analyzed in their characteristics corresponding to those of the process conditions. Fractures in these specimens were assessed using scanning electron microscopy (SEM) to assess the fracture surface. This was then used to analyze the fracture shape and determine whether anodizing the specimen led to the development of cracks on the joint surface. Results of the above test indicated that while the surface condition of the specimen and the temperature of the injection mold significantly influenced the strength of bonding, the content of the glass fiber did not.
DC-link Capacitor필름 형상에 따른 Joule-heat특성 분석
전용원,김영신,전의식,Jeon, Yong Won,Kim, Young Shin,Jeon, Euy Sik 한국반도체디스플레이기술학회 2020 반도체디스플레이기술학회지 Vol.19 No.1
As global warming accelerates, eco-friendly electric cars are being developed to reduce carbon dioxide emissions, and power conversion inverters are used to drive motors. Among inverter components, DC-link capacitor is heated by high current usage, which causes problems such as performance and life-saving of inverter. Although metal cases with good thermal performance have been used to solve this problem, it is difficult to apply them in practice due to insulation problems with other parts. In this paper, the Heat-Generation influence factor of DC-link capacitor is analyzed. Variables on heat-generation are set at 3 levels for film width, inductance, and film thickness. Box-Behnken to 13 tests using the design and minimal deviations, e.g. through the experiment three times by each level. The surface of the film k type by attaching the sensor current is measured temperature. Capacitance was set to a minimum level of 200 ㎌ and had a frequency of 16 kHz with Worst case, ambient temperature of 85℃ and a ripple current of 50 Ams was applied. The temperature at the measurement point was collected in the data logger after sampling at 1 minute intervals for 2 hours after saturation with the ambient temperature. This experiment confirmed that setup factors are correlated with heat-generation.