• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.34-35
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• 2011

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.431-433
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• 2008

본 논문에서는 원자력 발전소의 SG세관 검사를 위한 배열와전류프로브의 와전류탐상 특성을 해석하였다. 신호해석을 위해 원자력발전소 SG 세관의 내부 및 외부결함을 모델링하였으며, 결함의 깊이는 세관 두께의 40[%]로 하였다. 해석방법은 3차원 유한요소법을 이용하여 전자기 수치 해석을 수행하였다. 두 종류 결함의 수치해석 비교 결과 내부결함의 신호가 외부결함 신호에 비해 크게 발생되는 것을 확인할 수 있었으며, 또한 획득한 신호를 ASME 표준 시험편을 이용한 배열와전류 프로브의 와전류탐상 실험신호와 비교하였다. 본 논문의 결과는 원전설비검사를 위한 배열와전류프로브 신호의 특성해석에 도움이 될 것으로 사료된다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.29-30
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• 2009

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1394-1399
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• 2004

Recently solar energy is representative in the technology development and spread of alternative energy. Specially in condition of solar collectors, they have had very various shape. This paper reports experimental study about the application of Oscillating Capillary Tube Heat Pipe to flat-plate solar collector. In conclusion, overall temperature distribution of OCHP was investigated by charging ratio and inclination angle. Respective charging ratio is 15%, 20%, 40% and respective inclination angle is horizontal, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, perpendicular. As a result of experiment, charging ratio 20% heat pipe has shown the most uniform temperature distribution and also performance of heat transfer has been the best.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.695-701
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• 2013

The suppression of a thermocapillary flow (Marangoni flow) by a nonionic surfactant is experimentally investigated for evaporating pure water droplets on hydrophobic substrates. The experiment shows that as the initial concentration of the surfactant increases, the velocity and lifetime of the flow monotonically decrease. The result confirms the no-slip boundary condition at a liquid-air interface, which is explained on the basis of the previous model regarding the effect of surfactants on the no-slip condition. Interestingly, at an initial concentration much less than a critical value, it is found that depinning of the contact line occurs during the early stage of evaporation, which is ascribed to a reduction in the contact angle hysteresis owing to the presence of the Marangoni flow.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.177-184
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• 2000

The effect of the buyancy and thermocapillarity for differnent aspect ratio of flow field on melt motion and mass transfer has been numerically investigated in magnetic Czochralski crystal growth of silicon. During the process of crystal growth, the melt depth of crucible reduces so the aspect ratio of flow field also reduces. Therefore the shape of magnetic field of the flow field changes and the flow pattern also changes significantly. Together with the melt flow which forms the Marangoni convection (or thermocapillary flow) that comes from the inside the flow field, a flow circulation is observed near the corner close both to the crucible wall and the free surface. Due to this circulation, buoyancy effect has been turned out to be local rather than global. As the aspect ratio decreases, the radial component of the magnetic field prevails compared with the axial component in the flow field. Under the influence of this magnetic field, the melt flow and the temperature distribution in a meridional plane tend to depend on the radial position. As the aspect ratio decreases, the temperature gradient near the edge of the crystal decreases yielding smaller thermocapillarity, and the oxygen concentration near the crystal and the oxygen incorporation rate also decrease.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.627-633
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• 1997

Gonad structure, germ cell development and reproductive cycle of the smallmouth scorpionfish, Scorpaena miostoma were investigated based on histological method. Samples were collected monthly in the vicinity of Suyoung Bay, Pusan, Korea from November 1995 to October 1996. The testis is seminiferous tubule type in internal structure. Seminiferous tubule consists of numerous testicular cysts which contain numerous germ cells in same developmental stage. The ovary consists of several ovarian lamellae originated from ovarian outer membrane. Oogonia originated from the inner surface of the ovarian lamella protrude to the ovarian cavity in oocyte stage, and they are suspended by the egg stalk. Biological minimum size of female and male were 12.5cm in total length. Gonadosomatic index (GSI) of female (3.81) and male (0.23) were the highest in October. Reproductive cycle was classified into the following successive stages: in female, growing stage $(May\~August)$, maturation stage $(September\~October)$, ripe and spawning stage $(November\~December)$, recovery and resting stage $(January\~April)$, and in male, growing stage $(June\~August)$, maturation stage $(September\~October)$, ripe and spent stage $(November\~January)$ and recovery and resting stage $(February\~May)$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.951-956
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• 2011

Inconel alloys are generally used as steam generator tubes in nuclear power plants. These alloys are highnickel chromium alloys that exhibit excellent resistance to aqueous corrosion. In this paper, the effects of elevated temperatures such as an operating temperature of $320^{\circ}C$ on the fretting fatigue behavior of inconel 600 and 690. We observed that the plain and fretting fatigue limits at $320^{\circ}C$ were slightly lower than those at room temperature. The frictional forces varied depending on the number of load cycles. After each test, we studied the fretting fatigue mechanisms via SEM observations. These results can be used for structural integrity evaluations at elevated temperatures and for studying fretting damage in steam generator systems.

• Korean Architects
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• no.9 s.365
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• pp.43-79
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• 1999

서울은 600년이 넘는 역사와 전통을 간직한 우리 나라의 심장이자 얼굴이 되는 도시이다. 그러나 지난 30년간의 급격한 개발시대를 거쳐오면서 고도로서의 문화적 향기를 상실하였고, 매력과 특징이 없는 도시로 빠르게 변해가는 것은 안타까운 일이다. 이는 다가올 21세기가 서울의 정체성과 고유성을 더욱 필요로 할 것임에 비추어 더욱 그러하다고 할 수 있다. 서울은 급격한 경제성장으로 인하여 세계에서 그 유래를 찾기 어려운 급격한 변화를 보인 도시이다. 서울의 도심부를 둘러싸고 있는 북악, 인왕, 낙산, 남산은 옛 모습을 지니고 있으나 그 내부는 과거의 모습을 찾기 어렵고, 다만 현대적인 모습만이 흘러 넘치고 있을 뿐이다. 또한 서울은 물리적으로 엄청나게 성장하여 그 경계를 찾기 어려운 도시가 되어버렸다. 따라서 서울은 밝고 번영하는 모습과 어둡고 불합리한 모습이 공존하는 이상한 도시로서 인식되고 있다. 서울을 현재의 모습과는 전혀 새로운 환경으로 개발하고 보존할 수 있는 대책과 계획이 더욱 필요한 때이다. 공공과 민간 그리고 시민이 참여하여 600년 고도의 역사성이 드러나고 걷고 싶고 인간적인 분위기를 간직하며 다양한 기능과 형태가 조화롭게 공존하는 도시로 가꾸어갈 수 있는 지혜를 모아야 할 것이다. 이번 특집에서는 서울을 대상으로 하여 그 역사적인 흔적과 오늘의 모습 그리고 미래의 대안을 회고하고 진단하며 모색하는 기회를 갖기 위해 여러 전문가들의 글을 마련하였다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.2
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• pp.33-41
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• 2012

The component cooling water heat exchangers are critical components in a nuclear power plant. As the operation years of the heat exchanger go by, the maintenance costs required for continuous operation also increase. Most heat exchangers have carbon steel shells, tube support plates and flow baffles. The titanium tube is susceptible to flow induced vibration. The damage on carbon steel tube support rod and titanium tube around cooling water entrance area is inevitable. Therefore, analysis of internal flow around the component cooling water entrance and tube channel is a good opportunity to seek for failure prevention practice and maintenance method. The numerical study was carried out by FLUENT code to find out the causes of tube failure and its location.