표면처리에 따른 평기어 치의 표면거칠기 변화에 관한 연구 ( A Study on the Surface Roughness Variation of Spur Gear Teeth as a function of the Surface Treatment )

유장열,이성철,권오관,정태형 한국트라이볼로지학회 1991 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.7 No.2

고층 건물의 개구부형상과 단면적의 변화에 따른 풍응답 특성

유장열,장호면,유기표 대한건축학회지회연합회 2017 대한건축학회연합논문집 Vol.19 No.1

최근에 많은 고층건물에 새로운 재생 가능 에너지를 사용하기 위해 풍력 터빈 시스템을 설치하였다. 특히 풍력 발전기를 건물 내에 설치하여 풍력 발전 시스템을 구축하는 것은 안전한 에너지를 확보하기 위한 매력적인 방법이다. 그러나 대부분의 연구는 풍력 터빈의 효율과 바람에 의한 진동의 반응 효과를 다루었다. 풍력 터빈 설치를 위한 공간 준비는 충분히 고려되지 않았다. 본 연구에서는 고층 건물에 풍력 터빈을 설치할 수 있는 개구부의 모양과 단면적에 변화가 있는 건물에서 발생하는 바람에 의한 진동 반응의 특성에 대해 살펴 았다. 실험을 수행하기 위해 9 개의 풍력 모델이 구축 되었다.실험 결과에 따르면 풍속은 C 형> S 형> R 형의 순서로 개구의 형태에 따라 달라진다. 또한 면적이 감소함에 따라 풍속이 증가했다. Recently, many skyscrapers have installed wind turbine systems to use new renewable energy. In particular, building an integrated wind power generation system by installing a wind power generator inside a building is an attractive method to secure safe energy. However, most studies have dealt with the efficiency of wind turbines and the response effects of wind induced vibration; space preparation for wind turbine installations has not been sufficiently considered. This study reviewed the shapes of openings where wind turbines can be installed in skyscrapers and the characteristics of wind induced vibration responses occurring in the building with changes in across sectional area. Nine wind power models were constructed to carry out the experiment. According to the experimental results, wind speed varied with shape of opening in the order C-type>S-type>R-type. Moreover, wind speed increased as the area was reduced.

공동주택의 저층 필로티 유무에 따른 풍환경 평가

유장열,채명진,유기표 대한건축학회지회연합회 2018 대한건축학회연합논문집 Vol.20 No.1

Wind occurring within high-rise apartment complexes and in the surrounding area causes inconvenience for pedestrians and residents. This “building wind” that occurs between buildings is significantly affected by the shape and layout of the apartment buildings. In this paper, we measured the changes in wind velocity ratio due to placement of piloti on the floor level of different types of apartment complexes, and we assessed the results against several wind environmental criteria. We evaluated the wind environment of the apartment complexes by conducting wind tunnel tests for 16 different wind directions. For the experiment, we used data obtained from the meteorological observatory in the city of Daejeon, where apartment buildings with piloti are common. This experiment demonstrated an increase in wind velocity of up to 80% in the apartment complexes, depending on the building layouts. The presence of piloti reduced this increase in wind velocity by as much as 40%. The reduction in wind velocity due to piloti varied depending on the layout of the apartment buildings. 고층건물 아파트내부와 주변에서 발생하는 바람에 인해 보행자와 거주자에게 불편을 주고 있다. 이러한 건물들 사이에서 발생하는 빌딩풍은 아파트의 형태와 배치등에 많은 영향을 받게 된다. 본 논문에서는 아파트 저층 필로티 유무에 따른 아파트 단지의 다양한 형태별 풍속비의 변화를 측정한후에 풍환경기준과 비교하여 보았다. 아파트 단지내 풍환경 평가를위하여 풍동실험을 하였다. 실험측정풍향각은 16개 방향에 대해서 실시하였다. 실험대상지는 중정층 아파트가 많이 보급되어 있는 대전의 기상대 데이터를 이용하였다. 풍환경 실험결과 아파트 배치에 따라 단지내 풍속이 최대 80%이상 증가를 하였다. 그리고 필로티의 설치는 이러한 풍속증가를 최대 40%이상 감소를 시키고 있었다. 그러나 필로티도 아파트 단지의 배치에 따라 풍속의 감소효과는 다양하게 나타나고 있었다.

건물의 모서리 형태변화에 따른 건물 사이의 풍속에 미치는 영향분석

유장열,박민우,이남훈,유기표 대한건축학회지회연합회 2018 대한건축학회연합논문집 Vol.20 No.4

Recently, various building integrated wind power (BIWP) systems have been developed to produce energy by wind power generators installed in buildings. A BIWP does not require a support to position the wind turbine at the required installation height, and it has the advantage of high energy efficiency because the energy produced by the turbine can be used directly within the building, rather than being sent a far distance. In this study, a computational fluid dynamics (CFD) analysis was conducted to examine the wind speed variations occurring due to changes in the building corner morphology, with the goal of using these changes to increase the wind speed and improve the power generation efficiency of a wind turbine installed between two buildings. Round building corners increased the wind velocity by 2–4%, whereas corner cuts increased it by up to 1.5%, when compared to the basic rectangular corner. These shape changes were more advantageous with shorter distances between the buildings.

관통형과 단부형 필로티 천장부의 피크풍압계수 특성 분석

유장열,김근호,채명진,김영문,유기표,You, Jang-Youl,Kim, Geun-Ho,Chae, Myung-Jin,Kim, Young-Moon,You, Ki-Pyo 한국공간구조학회 2018 한국공간구조학회지 Vol.18 No.2

Various pilotis are installed in the lower part of high rise buildings. Strong winds can generate sudden airflow around the pilotis, which can cause unexpected internal airflow changes and may cause damage to the exterior of the piloti ceiling. The present study investigates the characteristics of peak wind pressure coefficient for the design of piloti ceiling exteriors by conducting wind pressure tests on high rise buildings equipped with penetration-type and end-type pilotis in urban and suburban areas. The minimum peak wind pressure coefficient for penetration-type piloti ceilings ranges from -2.0 to -3.3. Minimum peak wind pressure coefficient in urban areas was 30% larger than in suburban areas. In end-type piloti ceilings, maximum peak wind-pressure coefficient ranges from 0.5 to 1.9, and minimum peak wind-pressure coefficient ranges from -1.3 to -3.6. With changes in building height, peak wind pressure coefficient decreases as the aspect ratio increases. Peak wind-pressure coefficient increases with taller pilotis. On the other hand, when piloti height decreases, the absolute value of the minimum peak wind pressure coefficient increases.

표면처리에 따른 평기어 치의 표면거칠기 변화에 관한 연구 ( A Study on the Surface Roughness Variation of Spur Gear Teeth by the Surface Treatment )

유장열,이성철,권오관,정태형 한국트라이볼로지학회 1991 한국트라이볼로지학회 학술대회 Vol.13 No.-

고구마 ( Ipomoea batatas ) 의 현탁배양 (縣濁培養) 세포의 원형질체 배양에 의한 캘러스 형성

유장열,Daniel J . Cantliffe (Jang R . Liu) 한국식물학회 1989 Journal of Plant Biology Vol.32 No.4

Protoplasts were enzymatically isolated from suspension cltures of sweet potato. High yields of single protoplasts were produced from nonembryogenic cell aggregates. However, most protoplasts obtained from embryogenic cell clumps were spontaneously fused during enzyme treatment; a small portion of them remained single. Upon transfer to Murashige and Skoog`s(MS) liquid medium supplemented with 0.1 ㎎/l 6-benzyladenine(BA) and 1 ㎎/l 2,4-dichlorophenoxyacetic acid(2,4-D), protoplasts from nonembryogenic cell aggregates sustained cell divisions to form callus. Upon subculture onto MS media with 0.2 ㎎/l 2,4-D or without growth regulators, the callus did not give rise to any organs. On the other hand, first cell division of single protoplasts from embryogenic cell clumps was sporadically observed.

자율학습 - 음악과

유장열 한국음악교육학회 1986 음악교육연구 Vol.5 No.-

풍동실험과 전산유체해석을 이용한 고층건물의 풍환경 평가 비교

유장열,남병희,박민우,유기표 대한건축학회 2021 대한건축학회논문집 Vol.37 No.5

When a high-rise building is constructed adjacent to low-rise structures, damage is frequently caused by the associated strong wind patternsof which there are three typical forms. The first pattern is a separated flow which can occur at the corners of the buildings; the second ispilotis wind that occurs in narrow places such as columns installed in the lower parts of the high-rise building; and the third is a vortexflow which can occur between a low-rise building on the windward and a high-rise on the leeward. This study aimed to implement astandard evaluation of the wind environment and airflow characteristics around high-rise apartment blocks constructed next to low buildingsusing wind tunnel tests and computational fluid dynamics (CFD). In terms of validity, the correlation coefficient between the CFD and windtunnel results ranged between 0.6 and 0.8. Correlations below 0.8 were due to differences in the range of the wake flow area generated atthe backside of the target building according to wind direction angle and the effect of the surrounding buildings. In addition, a difference inaverage velocity ratio of the wake flow wind was observed in the values measured by the wind tunnel test and in the CFD analysis. Thewind velocity values of the CFD analysis were therefore compensated, and, as a result, although the correlations for some wind angles wereslightly reduced, most increased. 저층건물사이에 건설되는 고층아파트 주변의 풍환경 실험결과와 전산유체해석을 이용한 풍환경 기준평가와 측정지점별 기류특성에 대해 분석하였다. CFD해석결과의 유효성 검증을 위한 풍동실험 결과와 상관계수 중 0.8 이하인 풍향각에 대해서는 주변건물 등의 영향과 풍향각 별 해석대상 건물 후면에 발생하는 후류영역 범위의 차이로 판단된다. CFD해석결과와 풍동실험에서 사용되는 풍속계 계측치의 평균풍속 정의가 다름으로써 후류영역에서 평균풍속의 차이가 발생하는 것으로 판단된다. 따라서 CFD해석의 풍속값을 보정하여 상관계수를 분석하였다.

돌출 간판의 크기와 이격거리에 따른 풍압계수 분포 특성연구

유장열,유기표 대한건축학회지회연합회 2017 대한건축학회연합논문집 Vol.19 No.6

Recently, the abnormal weather due to global warming has led to increased frequency of typhoon and gale. Protruding Signboard is the most common type of outdoor advertisement in Korea which often causes falling accident due to strong wind, and led to serious damages on pedestrians or parked cars. However, there is no installation and structure standard for the sign board. Thus, this study conducted a wind tunnel experiment to analyze the influence of wind pressure coefficient distribution in accordance with the changes in experiment angles and separation distance of the protruding Signboard to wind pressure coefficient. There was difference in coefficient in accordance with the size of protruding Signboard, but there was no difference in coefficient in accordance with the separation distance between the sign board and building. The size of protruding Signboard was confirmed to be more influential to wind pressure coefficient than the separation distance.