• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.2
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• pp.265-273
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• 2003

Numerical analysis of bubble motion during nucleate boiling is performed by imposing a constant heat flux condition at the base of a heater which occurs in most of boiling experiments. The temporal and spatial variation of a solid surface temperature associated with the bubble growth and departure is investigated by solving a conjugate problem involving conduction in the solid. The vapor-liquid interface is tracked by a level set method which is modified to include the effects of phase change at the interface, contact angle at the wall and evaporative heat flux in a thin liquid micro-layer. Based on the numerical results, the bubble growth pattern and its interaction with the heating solid are discussed. Also, the effect of heating condition on the bubble growth under a micro-gravity condition is investigated.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1045-1048
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• 2003

In this paper, we studied plasma damage of MIS capacitor with $Al_2$O$_3$ dielectric film. Using capacitor pattern with the same area but different perimeters, we tried to separate etching damage mechanism and to optimize the dry etching process. After etching both metal and dielectric layer by the same condition, leakage current and C-V measurements were carried out for Pt/A1$_2$O$_3$/Si structures. The flatband voltage shift was appeared in the C-V plot, and it was caused by the variation of the fixed interface charge and the interface trapped charge. From I-V measurement, it was found the leakage current along the periphery could not be ignored. Finally, we established the process condition of RF power 300W, 100mTorr, Ar/Cl$_2$ gas 60sccm as an optimal etching condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.62-67
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• 2013

The influence of internal stress and joint strength(shear, tensile) according to the deposition conditions was investigated by the Polyimide substrate and ZnO thin film. Deposition thickness and temperature affect the internal stress and the internal stress was minimum at the 60nm and $200^{\circ}C$ of the deposition conditions. Tensile strength is large at the deposition condition that shear strength is large and the shear strength was about 50% of the tensile strength. The shear strength and tensile strength were large at deposition condition that internal stress was small. Crack occurred near the joint interface of Polyimide substrate and progressed along the interface until the final fracture.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.137-146
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• 2002

Geomembrane, compacted clay liner, and geosynthetic clay liner (GCL) are widely used to prevent leachate from leaking to adjacent geo-environment at a municipal solid waste (MSW) landfill. Interface shear strength between GCL and geomembrane installed at a landfill side slope is important properties for the safe design of side liner or final cover systems. The interface shear strength between two geosynthetics was estimated by a large direct shear test in this study. The shear strength was evaluated by the Mohr-Coulomb failure criterion. The effects of normal stress, hydration or dry condition, and a hydration method were investigated. The test results show that the interface shear strength and shear behavior varied depending up on the level of normal stress, the type of geosynthetic combinations, and a hydration method. When GCLs were sheared after being hydrated under 6kPa loading, the results were consistent with those published by other researchers. Summaries of friction angles, normal stress and hydration condition is presented. These friction angles could be used as a reference value at a site where similar geosynthetics are installed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.4
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• pp.306-317
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• 1995

Abstract Gallium arsenide crystal is usually grown from the melt by the horizontal Bridgman method. We constructed pseudo - steady - state model for crystal growth of GaAs which inclue melt, crystal and the free interface. Mathematical equations of the model were solved for flow, temperature, and concentration field in the melt and temperature field in the crystal. The location and shape of the interface were also solved simultaneously. In 2 - dimensional model, the shape of the interface is flat with adiabatic thermal boundary condition, but it becomes curved with completely conducting thermal boundary condition. In 3 - dimensional model, the interface is less curved than 2 - dimensional case and the flow intensity is similar to that of 2 - dimensional case. With the increase of flow intensity vertical segregation shows maximum value in both 2 - and 3 - D model. However, the maximum value occurs in lower flow intensity in 2 - D model because the interface is more curved for the same flow intensity.

• Journal of the Korean Geosynthetics Society
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• v.18 no.2
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• pp.45-54
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• 2019

This paper describes the results of finite element analysis (FEA), in order to investigate a characteristics of pile pullout behavior according to the conditions of the relative density and fines content in original ground. In the FEA, a boundary elements and strength reduction factors ($R_{inter}$) on pile-soil interface were applied to simulate appropriately the shear behavior at the pile-soil interface, and then the reliability of numerical analysis method was verified by comparison of FEA results and previous experimental research(You et al., 2018). In addition, a the deformation characteristics at the pile-soil interface and determination method of $R_{inter}$ value was laid out. The results showed that the FEA, based on the analytical model applied in this study simulates appropriately the characteristics of the pile-soil interface by pullout model test of pile. In order to apply the suggested $R_{inter}$ value, it is necessary to consider the condition of the relative density and the fines content in ground.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.69-75
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• 2008

Shear tests were carried out on interface between two concrete eco-blocks which comprise segmental retaining wall. Three interface conditions were considered : 1) direct contact of two blocks, 2) placing rubber pad between two blocks, 3) placing rubber pad and shear key between two blocks. According to shear tests, shear load-shear displacement relationship which was obtained from direct contact of two blocks was similar to elastic-perfectly plastic behavior. Ductile behavior of shear load-shear displacement relationship was observed for the interface condition of placing rubber pad. Apparent minimum shear capacities and apparent friction angles for the interface conditions of direct contact of two blocks, placing rubber pad between two blocks, placing rubber pad and shear key were 1.7 kN/m, $27.6^{\circ}$ and 4.2 kN/m, $26.2^{\circ}$ and 20.9 kN/m, $26.0^{\circ}$ respectively.

• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.200-206
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• 1996

When a Gaussian beam is incident to a planar dielectric interface at an angle other than Brewster angle or the critical angle of total reflection, we derive the six nonspecular effects of rotation, lateral shift, focal shift, Rayleigh length change, magnitude and phase changes in the complex amplitude of the reflected beam simultaneously by taking account of the boundary condition. In the derivation we assume a Gaussian beam of fundamental mode to emerge from the interface and then match at the interface the constant, linear, and quadratic variations of the amplitude and phase of the reflected beam with those of the incident beam multiplied by the reflection coefficient. Our calculation shows that the six nonspecular effects can result from a linear variation of the natural logarithm of the reflection coefficient at the interface.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.171-177
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• 2007

In this paper, an evaluation method of fracture toughness on interface cracks was investigated in friction welded dissimilar materials with interfacial edge cracks. To establish a reasonable strength evaluation method and fracture criterion, it is necessary to analyze stress intensity factor under the load and residual stress condition on friction welded interface between dissimilar materials. The friction welded specimens with an edged crack were prepared for analysis of stress intensity by using the boundary element method (BEM) and the fracture toughness. A quantitative fracture criterion for friction welded STS 304/SM 45C with interface crack is suggested by using stress intensity factor, F and the results of fracture toughness experiment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.2
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• pp.83-89
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• 2001

This paper introduces a power flow model of SSSC for voltage stability analysis of power system installed with Static Synchronous Compensators. The SSSC model is obtained from the injection model of voltage source inverter by adding the condition that SSSC injection voltage is in quadrature with current of SSSC-installed branch. This model is incorporated into modified CPF algorithm to study effects of SSSC on the security-constrained interface flow limit. Determination of interface flow limit is simply briefed. In case study a 771-bus real system is used to show that interface flow limit can be improved by appropriate control of SSSC in terms of voltage stability.