• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1627_1628
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• 2009

도로 교통에서의 보행자 안전을 위해 광양자테 레이저 어레이를 이용한 첨단 교통 신호 시스템 응용 기술을 소개한다. 저소비 전력 및 온도 특성이 뛰어난 광양자테 레이저는 대규모 어레이로 제작이용이하며 고속 모듈레이션 및 색순도 등이 뛰어나 광학 투사 시스템을 이용해 고해상도의 글자체 및 영상 구현이 가능하다. 횡단 보도 인근에 고집적, 고출력의 글자체 광양자테 레이저 어레이를 도로 바닥에 투사 및 영상화 시킴으로써 운전자 및 보행자의 교통 사고 예방에 획기적인 효과를 가져올 것으로 기대된다.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.225-230
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• 2016

Since the development of anodic aluminum oxide (AAO), extensive studies have been conducted ranging from fundamental research to the applications of AAO. Most of the research on AAO structures have focused on well-aligned nanoporous structures fabricated under specific conditions. This study investigated fabricable AAO structures with anodization performed with various temperatures, electrical potentials, and basal plane surfaces. As a result, nanoporous and nanofibrous structures were fabricated. The nanopores were formed at a relatively lower temperature and potential, and the nanofibers were formed at a relatively higher temperature and potential regardless of the basal plane surface. The shape of the base surface was found to influence the structural arrangement in nanoporous morphologies. These interesting findings relating to new morphologies have the potential to broaden the possible applications of AAO materials.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.371-374
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• 2006

Heat transfer characteristic near a sharp fin in a supersonic flow was studied. Infra-red thermography was used to obtain the variation of surface heat transfer coefficient distribution. The attack angle of fin is ranged from $10^{\circ}\;to\;20^{\circ}$ and the oil flow method was also conducted to understand a flow field near a sharp fin.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1135-1140
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• 2009

The present study has been studied on a thermal and flow characteristic of the microchannel waterblock with pass variations in 8 samples. Results of a numerical analysis using the CFX-11 were compared with results of an experiment. Numerical analysis and experiment were conducted under an input power of 150 W, inlet temperature of $35^{\circ}C$ and mass flow rates of $0.7{\sim}2.0\;kg/min$. The numerical results showed reasonably good agreement with the experimental results within about $3{\sim}5%$. Also, the numerical results showed that the sample 2 types with the 2 pass gave better performance than the sample 1 types with the 1 pass from the viewpoints of heat transfer and pressure drop.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.361-366
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• 2011

본 연구에서는 무인운영이 예정되어 있는 경량철도 지하역사 화재 시 안전대책을 강구하기 위하여 다양한 시나리오의 화재상황을 모사하여 FDS 사용코드를 이용해 화재유동현상을 분석하였다. 해석경계조건은 전동차 내부공간을 포함한 지하 3개 층과 설계에 반영된 환기설비를 적용하였으며, 약 500만 개의 격자를 34개 블록으로 나누어 계산하였다. 비상탈출 동선을 파악하여 주요 위치에서 피난경로상의 각 층 바닥으로 부터 1 m 높이의 한계온도와 연기층의 도달시간을 시나리오 별로 분석하여 보았다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.836-844
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• 2001

For the radiant floor heating system, the possibility of suboptimal prediction control was investigated by computer simulation and experiment. For this study, TRANSYS program was used and an experimental facility consisting of two rooms (3$\times$4.4$\times$2.8m) was built. The facility enabled simultaneous comparison of two different control strategies which implemented in a separate room. Results showed that outdoor air temperature prediction control was superior to the conventional outdoor air temperature compensation control for radiant floor heating system. However, more research for fine prediction of outside air temperature was required in the future.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.532-540
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• 2001

The objectives of this study are to analyze the control variables according to condensation occurrence, to find the range in floor surface temperature and frequency of condensation, and to evaluate the control methods through simulations when the radiant heating system is used for cooling. Through the simulation analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The results show that the lowest floor surface temperature is around $23^{\circ}C$, the surface condensation can be prevented by controlling indoor humidity within 20g/kg(DA0, and that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.269-274
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• 2008

The present study has been studied on a thermal and flow characteristic of the microchannel waterblock with flow distributions in each channels. Results of a numerical analysis using the CFX-11 are compared with results of an experiment. Numerical analysis and experiment are conducted under a heat transfer rate of 150W, inlet temperature of $20^{\circ}C$ and mass flow rates of $0.7{\sim}2.0\;kg$/min. Base temperature and pressure drop are investigated with standard deviations of mass flow rates in each channels of samples at 0.7 kg/min.

• Journal of the Speleological Society of Korea
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• v.46 no.47
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• pp.35-47
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• 1996

동굴의 환경파괴는 환경의 변화에서 오는 경우와 동굴 개발에 따른 인위적인 파괴 등에 의한 것이라고 하겠다. 동굴이 개발되면 그 당시부터 동굴의 파괴, 오손 및 오염은 시작된다. 물론 동굴이 개발되어 관광객의 출입이 많은 동굴에서는 개발 이전의 동굴환경이 그대로 보존되고 있을 리 만무하다. 그러나 이런 피해를 최소한으로 하고, 좋은 환경을 지속적으로 보완하기 위해서는 많은 노력이 필요하다. 화암동굴에 대한 환경보전을 위해 지질구조, 통로시설, 일반시설, 전기 및 조명, 생태환경, 운영관리 분야 둥에서 안전진단을 한 결과 여러 분야에서 동굴 개발 이후 미흡한 점이 지적되어 이에 대한 보완이 시급하다고 지적되었다. 동굴의 환경은 그 원칙이 암흑세계여야 한다. 더구나 항상 어둡고 동굴내의 온도와 습도가 크게 변하지 않는 원래의 동굴환경이 있어야 특수한 지하생물, 즉 동굴생물도 서식하게 되고 동굴 내의 이차생성물도 정상적으로 성장할 수 있는 것이다. 따라서 동굴의 환경보전은 가능하면 동굴 속의 이차생성물을 계속적으로 성장시켜 이른바 지하궁전 또는 지하복마전의 화려하고 무시무시한 동굴환경을 이루게 되는 것이다. 이와 같은 원리로 화암동굴 벽면의 종유벽(유석, 황금종유벽)과 대석주, 대석순, 그리고 벽면과 바닥의 석순 등이 이루어졌으므로 동굴환경의 유지는 절대적으로 필요한 것이다.

• Journal of the Korean Society of Industry Convergence
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• v.1 no.1
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• pp.21-30
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• 1998

The purpose of this study is to clarify the floor temperature on the human body and to estimate thermal comfort zone in a heated room. In order to evaluate the effects of floor heating, a series of experiments were carried out using Korean subjects. The following experiments were conducted: 1) to obtain the effective radiation area and configuration factors of the person in the sitting posture on a floor to get the mean radiant temperature, 2) to measure contacted area of the person to the floor to calculate conduction heat rate, 3) to measure convective heat transfer coefficient of the body and 4) to know the thermal comfort zone of indoor environment heated by ON-DOL. Subjects were exposed to the following conditions: combinations of air temperature $20^{\circ}C$, $22.5^{\circ}C$, $25^{\circ}C$, and floor temperature $20^{\circ}C$, $22.5^{\circ}C$, $25^{\circ}C$, $27.5^{\circ}C$, $30^{\circ}C$, $32.5^{\circ}C$, $35^{\circ}C$, $37.5^{\circ}C$, $40^{\circ}C$ under still air and 50% relative humidity in the controllable artificial climate chamber. To evaluate the effect of heat conduction between the body and a floor modified mean skin temperature was defined. Weighting coefficient to calculate mean skin temperature were modified with the contacted area. The experiments revealed a positive correlation between the modified operative temperature and the modified mean skin temperature. The modified mean skin temperature can indicate the effect of heat conduction between body and a floor surface.