• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.273-278
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• 2009

The experimental study is performed to investigate the optimum design of the system dissipating properly heat from the in-situ solar panel installed on site. For this purpose, six 12-Watts panels, which are set at the different conditions of the solar panels contained phase change material, changing the array of the aluminum fin and honeycomb at the back of the panel, are tested. PCM, which has $44^{\circ}C$ melting point, is chosen in this study. In order to enhance the thermal heat from the absorbed heat in PCM, finned aluminum plate is placed. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. As a result, the solar panel, which is combined with honeycomb and outward fins with PCM instead of placing the fine inward, is showing the best performance in terms of controling panel temperature and efficiency.

• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.10-15
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• 2010

The experimental study was conducted to optimize the system dissipating properly heat from the in-situ solar panel installed on the roof. For this purpose, six 12-Watt panels, which were consisted of the different design conditions such as containing phase change material(PCM), changing the array of the aluminum fin and honeycomb at the back of the panel, were tested. PCM, which had $44^{\circ}C$ melting point, was chosen in this study. In order to enhance absorbing and expelling heatin PCM, profiled aluminum fin was placed either inward oroutward from the panel. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. During the experiment, there were ranged to $26^{\circ}C\sim32^{\circ}C$ for outdoor temperature and $700W/m^2\sim1000W/m^2$ for irradiance. As a result, the solar panel, combined with honeycomb and outward fins with PCM instead of placing the fins inward, is showing the best performance in terms of controling panel temperature and its efficiency.

• 한국해양공학회지
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• 제37권5호
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• pp.215-224
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• 2023

While melting glaciers due to global warming have facilitated the development of polar routes, Arctic vessels require reliable anti-icing methods to prevent hull icing. Currently, the existing anti-icing method, i.e., the heating coil method, has disadvantages, such as disconnection and power inefficiency. Therefore, a carbon nanotube-based surface heating element method was developed to address these limitations. In this study, the numerical analysis of the surface heating element method was performed using ANSYS. The numerical analysis included conjugate heat transfer and computational fluid dynamics to consider the conduction solids and the effects of wind speed and temperature in cold environments. The numerical analysis method of the surface heating element method was validated by comparing the experimental results of the heating coil method with the numerical analysis results (under the -30 ℃ conditions). The surface heating element method demonstrated significantly higher efficiency, ranging from 56.65-80.17%, depending on the conditions compared to the heating coil method. Moreover, even under extreme environmental conditions (-45 ℃), the surface heating element method satisfied anti-icing requirements. The surface heating element method is more efficient and economical than the heating coil method. However, proper heat flux calculation for environmental conditions is required to prevent excessive design.

• 무역학회지
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• 제48권4호
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• pp.121-148
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• 2023

북극 해빙의 급속한 용해는 유럽과 아시아 사이의 실행 가능한 대체 해로로서 북극항로에 대한 관심을 증대시켜 왔다. 현재까지 북극항로의 기술적 실현 가능성, 안전성, 수익성, 환경 영향 등을 고려한 광범위한 연구가 진행되어 왔다. 북극항로는 국제 교역의 중요한 루트가 될 것이며, 무역 원활화를 위해서는 항만 효율성이 무엇보다 중요하다. 그럼에도 불구하고 북극항로의 중요한 위치해 있는 항만들, 특히 러시아 북극 항만들의 효율성 평가에 대한 연구가 제한적인 상황이다. 따라서 본 연구는 데이터 포락 분석(DEA) 모델과 Malmquist 생산성 지수를 적용하여 러시아 17개 항구의 운영 현황을 분석하고, 효율성을 평가하고자 한다. DEA 분석 결과, 주로 서부 지역에 속하는 항만들의 효율성이 높게 나타났으며, 특히 무르만스크와 바란데이와 같은 항구는 지속적으로 높은 효율성과 꾸준한 규모의 수익을 보여주고 있음이 규명되었다. DEA-Malmquist 모형 결과에 의하면 기술발전에도 불구하고 모든 항구에 대한 전반적인 자원 활용 효율성의 개선 정도가 상대적으로 적은 것으로 나타났다. 본 연구의 결과는 인프라 개발 계획 및 관련 정책 수립을 위한 기초자료를 제공하고, 북극항로 항만 당국에 실질적인 시사점을 제공한다.

• 한국주조공학회지
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• 제31권2호
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• pp.66-70
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• 2011

Hot dip aluminizing (HDA) is widely used in industry for improving corrosion resistance of material. The formation of intermetallic compound layers during the contact between dissimilar materials at high temperature is common phenomenon. Generally, intermetallic compound layers of $Fe_2Al_5$ and $FeAl_3$ are formed at the Al alloy and Fe substrate interface. In case of cast iron, high contact angle of graphite existed in the matrix inhibits the formation of intermetallic compound layer, which carry with it the disadvantage of a reduced reaction area and mechanical properties. In present work, the process for the removal of graphite existed on the surface of specimen has been investigated. And also HDA was proceeded at $800^{\circ}C$ for 3 minutes in aluminum alloy melt. The efficiency of graphite removal was increased with the reduction of particle size in sanding process. Graphite appears to be present both in the region of melting followed by re-solidification and in the intermetallic compound layer, which could be attributed to the fact that the surface of cast iron is melted down by the formation of low melting point phase with the diffusion of Al and Si to the cast iron. Intermetallic compound layer consisted of $Fe(Al,Si)_3$ and $Fe_2Al_5Si$, the layer formed at cast iron side contained lower amount of Si.

• 한국콘텐츠학회논문지
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• 제5권3호
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• pp.151-157
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• 2005

힐튼 호텔, 맥도날드와 같은 환대산업의 성공은 언어 및 문화적 배경이 다른 인적자원을 경제력 제고수단으로 효율적으로 관리한 결과이다. 이처럼 본 연구의 목적은 창의적인 아이디어, 네트워크 다양화, 기업이미지 제고, 우수인력을 극대화할 수 있고, 이로 인해 발생될 수 있는 부정적인 요소를 최소화하기 위한 가이드 라인을 제시하고자 한다. 1. 다양한 문화를 이해하고 접할 수 있는 교육 및 훈련 프로그램이 학교 교육차원에서 먼저 제공되어야 한다. 2. 감정과 인식에 대한 차이를 자국어로 설명된 비디오 교육시스템으로 그릇된 인식(misperceptions), 그릇된 평가(misevaluations), 불신(mistrust)과 같은 apos;misfactorapos; 요소를 줄여야 한다. 3. 각 국가의 풍습 및 음식문화, 국제 비즈니스 매너, 토론회와 같은 다양하고 체계적인 프로그램이 필요하다. 4. 경영자는 다문화에는 다양성과 일관성의 양면성이 있음을 명심해야 한다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.42.2-42.2
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• 2011

$TiO_2$ films were modified by adding a glass frit as a light scattering particle and applied to an anode electrode in dye-sensitized solar cells (DSSCs) to enhance the adhesion between $TiO_2$ and fluorine doped transparent oxide (FTO). Low melting point glass frits at contents of (3 to 7wt%) were added to the nano crystalline $TiO_2$ films. The light scattering properties, photovoltaic properties and microstructures of the photo electrodes were examined to determine the role of the low glass transition temperature ($T_g$) glass frit. Electrochemical impedance spectroscopy, Brunauer-Emmett-Teller method and scratch test were conducted to support the results. The DSSC with the $TiO_2$ film containing 3wt% low Tg glass frit showed optimal performance (5.1%, energy conversion efficiency) compared to the $TiO_2$-based one. The photocurrent density slightly decreased by adding 3wt% of the frit due to its large size and non conductivity. However, the decrease of current density followed by the decrease of electron transfer due to the large frit in $TiO_2$ electrode was compensated by the scattering effect, high surface area and reduced the electron transfer impedance at the electrolyte-dye-$TiO_2$ interface. The stability of the photo electrodes was improved by the frit, which chemically promoted the sintering of $TiO_2$ at relatively low temperature ($450^{\circ}C$).

• 대한환경공학회지
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• 제32권9호
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• pp.857-861
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• 2010

매년 대도시 지역과 그 주변에 오존농도가 환경기준을 초과하는 빈도가 증가하여 오존주의보 발령횟수가 증가하는 추세이다. 따라서 오존의 전구물질인 VOCs에 대한 제어과정이 시급한 실정이다. 국내에서 발생되는 폐기물 중 소각재와 하수슬러지는 발생량이 증가됨에 따라 그 처리 방안이 요구되고 있다. 소각재와 다른 폐기물을 이용하여 건축외장재를 제조하여 소각재 중의 유해중금속을 안정화시키고 제조한 외장재로 대기 중의 VOCs를 흡착, 제거할 수 있다면 환경 부하 저하, 자원 재활용 및 VOCs control이라는 면에서 매우 유용할 것으로 판단된다. 제조한 외장재의 VOC 흡착특성을 알아보기 위해 벤젠 흡착실험과 SEM분석, BET분석을 수행하였고 외장재의 흡착특성을 유지하기 위해 광촉매 코팅을 하여 그 효과를 알아보았다. 실험결과 벤젠 제거 능력은 74~96%로 높게 나타났고 제조한 외장재의 표면에는 다양한 공극이 발달되어 있음을 알 수 있었다. 또한, 외장재의 환경안정성을 알아보기 위해 중금속 용출실험을 수행한 결과 중금속이 안정화 되어 용출양이 현저히 감소한 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제41권5호
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• pp.561-574
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• 2009

First ex-vessel core catcher has been applied to the practical design of NPPs with VVER-1000 reactors built in China (Tyanvan) and India (Kudankulam) for severe accident management (SAM) and mitigation of SA consequences. The paper presents the concept and basic design of this crucible-type core catcher as well as an evaluation of its efficiency. The important role of oxidic sacrificial material is discussed. Insight into the behaviour of the molten pool, which forms in the catcher after core relocation from the reactor vessel, is provided. It is shown that heat loads on the water-cooled vessel walls are kept within acceptable limits and that the necessary margins for departure from nucleate boiling (DNB) and of vessel failure caused by thermo-mechanical stress are satisfactorily provided for.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.736-738
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• 2001

Induction heating is utilized in a large and ever-increasing number of application. The most prominent of these are billet heating, heat treating, metals joining, and metal melting. In these day, heating roll, a kind of induction heating, is widely used in curing of coatings and fiber industry. In this paper, we analyzed thermal characteristic analysis of induction heating roll according to primary material. Using this analysis results, efficiency of induction heating roll could be improved.