• Journal of Information Display
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• 제3권2호
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• pp.13-18
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• 2002

Numerical simulation is one of the most useful tools to study gas discharge phenomena that occur in alternating current plasma display panel (AC-PDP) cell. Most PDP cell simulations have been performed for two-dimensional cell, is cross-section along the address electrode. We developed a three-dimensional PDP simulator and applied it to a T-shaped electrode cell in order to show the effects of sustain electrode shape that cannot be included in two-dimensional simulation. The dependence of power consumption on electrode shape and area in the simulation showed the same trend as experiment.

• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.970-975
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• 2002

We suggests an effective method to construct time-varying C-obstacles in the 3-dimensional configuration space (C-space) using free arc. The concept of free arc was defined mathematically and the procedure to find free arc in the case off-dimensional C-space was derived in [1]. We showed that time-varying C-obstacles can be constructed efficiently using this concept, and presented simulation results for two SCARA robot manipulators to verify the efficacy of the proposed approach. In this paper, extensions of this approach to the 3-dimensional C-space is introduced since nearly all industrial manipulators are reasonably treated ill the too or three dimensional C-space f3r collision avoidance problem The free arc concept is summarized briefly and the method to find lice arc in the 3-dimensional f-space is explained. To show that this approach enables us to solve a practical collision avoidance problem simulation results f3r two PUMA robot manipulators are presented.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.526-526
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• 2012

DC magnetron discharges were studied using three-dimensional self-consistent particle-in-cell and Monte Carlo collisional (PIC-MCC) simulation codes. Two rectangular sputter sources (120 mm * 250 mm and 380 mm * 200 mm target sizes) were used in the simulation modeling. The number of incident ions to the Cu target as a function of position and simulation time was obtained. The target erosion profile was calculated by using the incident ions and the sputtering yields of the Cu target calculated with SRIM codes. The maximum ion density of the ion density distribution in the discharge was about $10^{10}cm^{-3}$ due to the calculation speed limit. The result may be less than one or two order of magnitude smaller than the real maximum ion density. However, the target erosion profiles of the two sputter sources were in good agreement with the measured target erosion profiles except for the erosion profile near the target surface, in which which the measured erosion width was broader than the simulation erosion width.

• 한국시뮬레이션학회논문지
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• 제11권3호
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• pp.13-22
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• 2002

This paper describes an automated evaluation of electrostatic field for micro motors whose sizes range 10 to 103um. Electric field modeling in micro motors has been generally restricted to in-plane two-dimensional finite element analysis (FEA). In this paper, the actual three-dimensional geometry of the micro motor is considered. An automatic FE mesh generation technique, which is based on the fuzzy knowledge processing and computational geometry techniques, is incorporated in the system, together with one of commercial FE analysis codes and one of commercial solid modelers. The system allows a geometry model of concern to be automatically converted to different FE models, depending on physical phenomena to be analyzed, electrostatic analysis and stress analysis and so on. The FE models are then exported to the FE analysis code, and then analyses are peformed. Then, analytical analysis and FE analysis about the torque generated by electrostatic micro motor are performed. The starting torque is proportional to $V^2$, the calculated starting torque from the two-dimensional analytical solutions are three times larger than those from the three-dimensional FE solutions.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.225-230
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• 2003

The moonpool is a vertical well ill floating barge, frequently found in drilling ships and in diving support vessel. In this paper, numerical simulation of two-dimensional flow in moonpool situated in moving vessel is carried out using the commercial software FLUENT. The focus of the simulation is to understand drag generation mechanics of moonpool flow. To examine the effect of free surface motion on the drag, simulations are also carried out by employing two different boundary conditions at the free surface.

• 한국분말재료학회지
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• 제7권4호
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• pp.189-196
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• 2000

Effect of ball filling ratio on the behavior of balls motion and their collision characteristic in a tumbler-ball milling of metal powder are investigated by a computer simulation. The discrete element method and the extended Kelvin model composed of nonlinear spring and nonlinear dashpot were employed in the simulation. It can be possible that analysis of the individual balls motion in a three-dimensional actual mill by the two-dimensional model simulation, since the simulated trajectories of ball paths are in relatively good agreement with the actual ones. It knows that the balls motion in the tumbler-ball mill is strongly influenced by the surface conditions of the balls and mill container wall. The energy consumption of the individual balls during impact and the impact frequency of the individual balls increased with an increase in the ball filling ratio and showed maximum values at about 50-60% ball filling ratio, and then decreased.

• 대한기계학회논문집B
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• 제32권5호
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• pp.359-366
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• 2008

A two-dimensional thermal model of proton exchange membrane fuel cell with large active area is developed to investigate the performance of fuel cell with large active area over various thermal management conditions. The core sub-models of the two-dimensional thermal model are one-dimensional agglomerate structure electrochemical reaction model, one-dimensional water transport model, and a two-dimensional heat transfer model. Prior to carrying out the simulation, this study is contributed to set up the operating temperature of the fuel cell with large active area which is a maximum temperature inside the fuel cell considering durability of membrane electrolyte. The simulation results show that the operating temperature of the fuel cell and temperature distribution inside the fuel cell can affect significantly the total net power at extreme conditions. Results also show that the parasitic losses of balance of plant component should be precisely controlled to produce the maximum system power with minimum parasitic loss of thermal management system.

• 한국재료학회지
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• 제11권11호
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• pp.929-935
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• 2001

Two-dimensional computer simulations were conducted on percolation structure in which second phases of various aspect ratios were arranged in a lattice (matrix). The second phases were randomly arranged in an array with two different computational programs; one prohibiting an overlap among second phases and the other allowing the overlap. From the simulation prohibiting the overlap, it was predicted that a complete path was formed at less amounts of the second phase with higher aspect ratios. In the simulation allowing the overlap, a complete path throughout the array was formed by arranging the second phase of an aspect ratio of 1. 5, 20, 100 with less than 59%, 43%, 19%, 4% in the array, respectively.

• 한국연소학회지
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• 제7권1호
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• pp.52-57
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• 2002

A numerical investigation using a commercial CFD program of the Inter-Phase Slip Algorithm has been carried out for detail characteristics of particle motions and bubble behaviors in a two dimensional fluidized bed. The bed simulated has been operated with three different distributor geometries, such as bubble cap, nozzle, and perforated plate types. Experiments using a slit-type two-dimensional fluidized bed and a cylinder-type fluidized bed have been performed in order to confirm the simulation model. In addition, the numerical results are compared with the wellknown correlation of bubble sizes and bubble rising velocities by Mori and Wen [1]. The simulation model that we applied is shown to be useful to understand the relation between bubble behaviors and distributor geometries.

• 한국산학기술학회논문지
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• 제5권4호
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• pp.336-339
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• 2004

본 논문은 Al/sub x//Ga/sub 1-x//As/Ga/sub y//In/sub l-y//As/GaAs 이종접합 소자의 2차원적 산란율을 해석하였다. 사각 양자 우물의 전자 준위는 슈뢰딩거와 포아송 방정식의 연계풀이에 의해 수치해석 적으로 해석하였다. 수치해석으로 얻어진 파동함수와 에너지 준위를 이용하여 이 구조에서 주요한 2차원 산란율들을 구하였다. 극성광학 포논, 음향 포논, 압전 산란, 이온화된 불순물 산란, 그리고 합금 산란이 첫 번째 두개의 하부 밴드에 대해 고려되었다. 또한 2차원에 대해 구하여진 이 결과는 같은 영역에서의 3차원 산란율과 비교하였다.