• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.993-995
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• 1998

We fabricated fiber gratings with three different Ge-doped fibers exposed to 60atm pressure of Hz gas at 90"C for different times and studied the effects of Ge-doping concentration and $H_2$ loading time on the growth of gratings. According to experiments. the growing effect of hydrogen loading on high Ge-doped fiber was great.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1503-1505
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• 2001

방사선이 폴리에틸렌 박막의 결정구조에 미치는 영향은 결정구조의 전 영역에서 결정 격자의 결함으로 나타났으며, 이는 탄탄한 연결고리를 형성하고 있는 분자쇄의 단절로 인하여 결정 내부 및 표면에서 화학작용에 의한 기포가 발생한 것으로 판단된다. 또한, 방사선량의 증가에 따라서 그 결함은 비례적으로 증가하였으며, 주파수에 따른 유전특성 고찰결과는 10 MHz 이상의 범위에서 유전율이 급격히 증가하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.100-110
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• 2007

A new design approach for a delicate treatment of complex geometries such as a wing/body configuration is arranged using overset mesh technique under large scale computing environment for turbulent viscous flow. Various pre- and post-processing techniques which are required of overset flow analysis and sensitivity analysis codes are discussed for design optimization problems based on gradient based optimization method (GBOM). The overset flow analysis code is validated by comparing with the experimental data of a wing/body configuration (DLR-F4) from the 1st Drag Prediction Workshop (DPW-I). In order to examine the applicability of the present design tools, careful design works for the drag minimization problem of a wing/body configuration are carried out by using the developed aerodynamic shape optimization tools for the viscous flow over multiple-body aircraft geometries.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.149-156
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• 2007

A three-dimensional inviscid flow solver has been developed based on unstructured meshes for the simulation of steady and unsteady flowfields around a generic fighter aircraft and for the investigation of the aerodynamic interference between the external stores and the tail surfaces. The flow solver is based on a vertex-centered finite-volume method and an implicit point Gauss-Seidel relaxation scheme. To validate the flow solver, calculations were made for a steady flow and the computed results were compared with experimental data. An unsteady time-accurate computation of the generic fighter aircraft with external stores at transonic flight conditions showed that the external stores cause undesirable vibration on the horizontal tail surface due to the mutual interference between their wake and the horizontal tail surface. It was shown that downward deflection of the trailing edge flap significantly reduces the undesirable interference effect.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 추계 학술대회논문집
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• pp.111-114
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• 2004

CFD code that simulates stator-rotor interactions is developed applying parallel computing method. Modified Multi-Block Grid System which enhances perpendicularity in grid and is appropriate in parallel processing is introduced and Patched Algorithm is applied in sliding interface which is caused by movement of rotor. The experimental model in the turbo-machine is composed of 11 stators and 14 rotors. Analyses on two test cases which are one stator - one rotor model and three stators - four rotors model are performed. The results of the two cases have been compared with the experimental test data.

• 한국전산유체공학회지
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• 제5권2호
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• pp.20-27
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• 2000

An unstructured implicit Euler solver is parallelized on a Cray T3E. Spatial discretization is accomplished by a cell-centered finite volume formulation using an upwind flux differencing. Time is advanced by the Gauss-Seidel implicit scheme. Domain decomposition is accomplished by using the k-way n-partitioning method developed by Karypis. In order to analyze the parallel performance of the solver, flows over a 2-D NACA 0012 airfoil and 3-D F-5 wing were investigated.

• 한국광학회지
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• 제8권5호
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• pp.357-361
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• 1997

밀도반전된 Nd:YAG에서 자체 교차하는 빔경로를 구성하여 위상공액파 레이저를 발진 시켰다. 서로 교차하는 두빔에 의한 spatial hole burning에 의해 3차 비선형 분극이 유도되어 레이저 공진기 내부의 위상 왜곡(phase distortion)이 자체 보정됨을 관측하였고, 레이저 이득체내에서 형성되는 동적 부피 격자의 생성과 소멸에 의한 효과로 반치폭 20 나노초의 자연 Q-switched 레이저 펄스가 발진되었다. 평균 펄스당 출력 에너지는 10 Hz 동작에서 200 mJ로 측정되었으며, 최대 전체 출력 효율은 0.8%로 나타났다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.193-200
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• 1999

An unstructured implicit Euler solver is parallelized on a Cray T3E. Spatial discretization is accomplished by a cell-centered finite volume formulation using an unpwind flux differencing. Time is advanced by the Gauss-Seidel implicit scheme. Domain decomposition is accomplished by using the k-way N-partitioning method developed by Karypis. In order to analyze the parallel performance of the solver, flows over a 2-D NACA 0012 airfoil and a 3-D F-5 wing were investigated.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.78-85
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• 2011

The Vortex-In-Cell(VIC) method combined with panel method is applied to the analysis of incompressible unsteady viscous flow. The dynamics of resulting flow is governed by the vorticity transport equation in Lagrangian form with vortex particle representation of the flow field. A regular grid which is independent to the shape of a body is used for numerical evaluation based on immersed boundary technique. With an introduction of this approach, the development and validation of the VIC method is presented with some computational results for incompressible viscous flow around two or three dimensional bodies such as wing section, sphere, finite wing and marine propeller.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.208-211
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• 2001

Hot wall epitaxy 법으로 GaAs(100) 기판 위에 $Zn_{1-x}Mn_xTe(0{\leq}x{\leq}1)$ 단결정 박막을 성장하였다. XRD 스펙트럼으로부터 $Zn_{1-x}Mn_xTe$ epilayer들이 전 영역에 걸쳐 zincblende 구조임을 알았다. double crystal rocking curve(DCRC)로부터 격자상수를 계산하고 이훌 이용하여 조성비를 계산하였다. ZnMnTe 단결정 박막의 DCRC 반치폭은 Mn 조성비가 증가함에 따라 급격하게 증가하다가 포화되는 모습을 나타내었다