• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.390-395
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• 2008

This study is performed to understand three dimensional characteristics of weld residual stress for the surface weld on the stainless steel plate. AISI 304 plate with one path weld on the surface was used as a test specimen. Finite element analysis was done to analyze thermal transient and residual stress due to weld. The result of finite element analysis was validated by previous paper and measurement data. Among various techniques for residual stress measurement, instrumented ball indentation method was applied. The calculated residual stresses by finite element analysis showed good agreement with the measured results.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.338-338
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• 2015

VRFB(Vanadium Redox Flow Battery)는 바나듐계 이온을 전해질로 사용하는 레독스 흐름 전지로, 전해질의 양이 전지의 용량을 결정하기 때문에 주로 대용량의 전력이 필요한 플랜트 등에서 주로 사용하는 전지이다. 이 VRFB내에는 Current collector의 부식 방지용으로 두꺼운 Graphite판을 BP(Bipolar plate)로 사용한다. 플랜트에서는 대용량 전지를 필요로 하여 Single stack으로는 사용되기 어렵고, Multi stack으로 주로 사용한다. Multi stack의 경우, 수 백장의 BP가 들어가 전지의 부피가 매우 커지게 되고, 이에 본 연구에서는 BP의 두꺼운 Graphite를 얇은 $TiO_2$ 기판으로 교체하여 성능을 비교하는 연구를 진행하였다. Ti 금속기판을 양극산화법으로 $TiO_2$ 나노튜브 구조를 만든 후, $TiO_2$의 전도도 향상을 목적으로 $IrO_2$를 코팅하였다. 결과적으로 기존의 Graphite에 비해 전기화학적 특성이 향상되었음을 확인하였으며, Cell test를 통해 VRFB의 성능을 평가하였다.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.121-128
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• 1998

In this study, when tension and bending stress act on plate simultaneously, stress intensity factor is analyzed at crack tip with using BEM(Boundary Element Method). In this analysis, stress intensity factors(S.I.F) are defined for variable ligament, aspect and stress ratio($\sigma$T/$\sigma$B). Consequently, predicted that crack grow to depth direction at low aspect and ligament ratio in tension stress and to surface direction in bending stress. Tension and bending stress act on plate same time, effect of tension stress in the first stage and effect of bending stress in the after stage was to observed. The outbreak of secondary crack in backside is under the control of stress amplitude and predict that the point of outbreak is mear backside.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2023-2028
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• 2008

In present study, the flow field near the fin surface of plate fin - oval tube heat exchanger with delta wing vortex generator was numerically analyzed. As results, the well developed vortex behind delta wing was observed. These vortex can improve heat transfer fin surface behind delta wing vortex generators.

• 한국해양공학회지
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• 제11권3호
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• pp.20-28
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• 1997

The fatigue crack propagation properties and fatigue life of two kinds of Al body panel for automobile were examined experimentally by using the plate specimen and the single spot welding specimen. The fatigue limit of spot welding specimens was lower than that of a plate specimen. The fatigue limit was similar in two kinds of spot welding specimen. The shape and size of crack propagation were observed and measured on beach mark of fracture surface. The crack propagation of surface crack specimen showed almost same tendency to that of a thick plate as almost semi-elliptical. In spot welding specimen, the fatigue crack occurred in inside surface of nugget area was almost semi-elliptical. The crack growth rate can be explained using equation of stress intensity factors.

• 한국표면공학회지
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• 제48권3호
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• pp.87-92
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• 2015

Carbon thin films were deposited on STS 316L sheets by inductively coupled plasma enhanced magnetron sputtering with or without substrate bias voltage. Typical Raman spectrum for amorphous diamond-like carbon (DLC) was obtained, and the interfacial contact resistance (ICR) was measured to show its conductive nature. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion mechanism of the carbon coating under the polymer electrolyte membrane fuel cell (PEMFC) condition. According to the pore-corrosion mechanism, the electrolyte penetrates the carbon coating through the pores and reacts with the substrate. As the substrate corrosion proceeds, the pore enlargement occurs and the surface area of the substrate exposed to the electrolyte. Applicability of the carbon coating for the PEMFC bipolar plate was evaluated by potentiodynamic polarization experiments. Finally, an adhesion problem was briefly considered.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.55-58
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• 2002

To control the frost formation, a temperature variation of the cooling plate and characteristics on hydrophilic and hydrophobic surfaces was attempted. As a temperature variation of the cooling plate, being closely related to the frost layer density of frost layer is found to be affected by the melting process inside the frost layer during the heating period. At characteristics on surface, completely different structures of frost are appeared in the initial stage of frost formation due to the difference in surface conditions, while those effects are vanished with time. It is found that the frost thickness, density and heat flux characteristics are closely associated with the frost structure.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.194-198
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• 2006

In this study, numerical modeling was performed to analyze air flow including radiation heat transfer inside a small chamber. Characteristics of heat transfer between source plate and target through glass are investigated for various surface temperature of heat source plate with buoyancy effect due to gravity force. Conduction heat transfer through the glass is considered and heat source plate is assumed to be a black body. Target surface temperature is largely affected by the radiation heat transfer. It can also be seen that as the source temperature increases target surface is dominated by radiation rather than convective heat transfer by air.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.225-232
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• 2022

In this paper, the physical neutral surface concept is applied to study the wave propagation of functionally graded (FG) circular plate, the wave equation is derived by Hamiltonian variational principle and the first-order shear deformation plate model. Then, we convert the equations to dimensionless equations. The exact solution of wave propagation problem is obtained by Laplace integral transformation, the first order Hankel integral transformation and the zero order Hankel integral transformation. The results obtained by the current model are very close to those obtained in the existing literature, which indicates the correctness and reliability of this study. Moreover, the effects of the functionally graded index parameters and pore volume fraction on the wave propagation are also discussed in detail.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.31-32
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• 2023

Recently, with the digitalization of the construction industry, free-form building construction technology is developing. However, the technology for manufacturing free-form concrete panels is still insufficient. In this study, the surface error of the FCP according to the thickness of the lower silicon plate, which is a component of the existing lower multi-point press, was analyzed in order to manufacture a precise FCP. As a result of the analysis, it was found that the thinner the thickness, the larger the error value. These results can be used as a basis for existing research and are expected to be used for research on high-quality FCP manufacturing technology.