• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.513-518
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• 2011

In this paper, a unified design environment is developed for the optimization of electric machines based on continuum sensitivity. For electromagnetic (EM) system analysis, COMSOL scripting environment is used. Optimization module is developed by MATLAB programming, which can be combined with COMSOL script commands. The modules are combined into one MATLAB project, and iteration process necessary for the optimization of EM system can be performed efficiently. During the design process, visual feedback of the current design status is given to the designer. In addition, the B-Spline parametrization of the nodal points is implemented to obtain smooth boundary of the device. The developed software is applied to the problem of finding uniform flux density distribution at the air gap of an electromagnet to verify its feasibility and effectiveness.

• Journal of Environmental Science International
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• v.11 no.9
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• pp.925-931
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• 2002

Land-use types should be included in air pollutant diffusion model because a complex mixture of various land-use patterns with computational grid can make errors in calculation of several parameters. However, the air pollutant diffusion model has generally been treated with a uniform component with land-use type in each mesh because of the complexity of the simulation. This study presents a numerical simulation of the horizontal distribution of $O_3$dry deposition velocity during summertime in Busan metropolitan city. The calculation of the meteorological field was conducted using the land cover data. Simulation has been performed by the following two scenarios : (1) one with current land cover data, and (2) the other with only land and sea for the surface characteristics. The results from each scenario reveals considerable differences on the meteorological fields and these differences can cause changes in the calculation values of $O_3$deposition velocity.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.101-108
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• 2000

This paper presents the results of finite element analysis on the seismic response of a soil-reinforced segmental retaining wall subjected to a prescribed earthquake record. The results of finite element analysis indicate that the maximum wall displacement occurs at the top, exhibiting a cantilever type of wall movement. Also revealed is that the increase in reinforcement force is more pronounced in the upper part of the reinforced zone, resulting in a more or less uniform distribution. None of the design guidelines appears to be able to correctly predict the dynamic force increase when compared with the results of finite element analysis. The results demonstrated that there exist critical stiffness and length of reinforcement beyond which further increase would not contribute to additional reinforcing effect. Based on the findings from this study, a number of implications to the current design methods are discussed.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.201-204
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• 2002

A large area inductively coupled plasma which is applicable to LCD processing is built with a modified single loop RF antenna. Combination of parallel and series paths of RF current through the antenna induces local enhancement of plasma density, which in turn provides uniform plasma density near the substrate. The plasma density distribution is measured and compared with that of the conventional single loop antenna. Aisotropic etching of photoresist is performed, and it is found that etch uniformity is improved by 3％ from 15% of the conventional etcher over 350$\times$300mm glass substrates. Photoresist etching rate and uniformity can be further improved by applying a periodic weak axial magnetic fieid.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.297-301
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• 2000

ELF 전자파의 생물학적인 영향 평가를 위한 in vitro 세포 실험에서 노출장치의 설계는 코일내피 유도기전력(E)과 전류밀도(J) 해석과 함께 이루어져야 한다. 균일 자기장 속에서 세포를 배양할 경우애도 배양기내의 전도성 매질로 인해 균일한 E와 J가 분포하지 않는다. 따라서 균일한 ELF 자기장 노출장치로부터 발생되는 샘플 매질 내에서의 E나 J를 정확히 예측하는 것은 in vitro 세포실험의 성공여부를 가늠 할 정도로 매우 중요한 정보가 된다. 이에 본 논문에서는 in vitro 실험에 적합한 ELF in vitro 노출 장치를 설계하고 노출 장치에 대한 전자기학적 평가를 수행하였다. 코일 내에서 샘플 매질의 유무와 샘플 내에서도 세포가 놓여질 임의의 위치에 따라 E와 J를 예측하고 검증을 위한 측정과 시뮬레이션을 시도하였다. 노출장치는 헬름 홀쯔 코일로 제작되었고 자기장의 세기는 1-2OG 범위 내에서 가변이 가능하다. 또한 코일내의 자기장의 분포가 균일(uniform), 비균일(nonuniform)만 두 가지모드를 각각 제작하여 보았다.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.368-375
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• 2010

To alleviate NOx emission, a variety of approaches has been applied. In marine diesels, the application of SCR systems has been considered an effective exhaust aftertreatment method for NOx emission control. Most current SCR systems use a various catalyst for the reaction of ammonia with NOx to form nitrogen and water. In theory, it is possible to achieve 100% NOx if the NH3-to-NOx ratio is 1:1. However, the reaction has a limited non-uniformity of the exhaust gas flow and ammonia concentration distribution. Therefore it is necessary to investigate the optimum flow conditions. In order to achieve uniform flow at monolith front face, we are equipped with a various mixed device. In this paper, it is presented that the mixed devices play an important role improvement of flow patterns and particle distributions of NH3 by numerical simulation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.39-45
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• 2012

Currently, the aircraft industry, aircraft parts as well as airframe have been developed in producing, the aircraft parts and fuselages have been produced the product by cutting rather than forging and casting because of the residual stress and stress concentration. In this study, the aircraft is being used in many parts of aluminium alloy 2024 in wire-cut E.D.M. The selected experimental parameters are peak current, no-load voltage, off time and feed rate. It is found that cutting mountain part on surface roughness of the curve 0.3mm than 0.25mm diameter wire electrode is stable in many uniform distribution.

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.9-16
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• 2010

To alleviate NOx emission, a variety of approaches has been applied. In marine diesels, the application of SCR systems has been considered an effective exhaust aftertreatment method for NOx emission control. Most current SCR systems use a various catalyst for the reaction of ammonia with NOx to form nitrogen and water. In theory, it is possible to achieve 100% NOx if the $NH_3$-to-NOx ratio is 1:1. However, the reaction has a limited non-uniformity of the exhaust gas flow and ammonia concentration distribution. Therefore, it is necessary to investigate the optimum flow conditions. In order to achieve uniform flow at monolith front face, we are equipped with a various mixed devices. In this paper, it is presented that the mixed devices play an important role improvement of flow patterns and particle distributions of $NH_3$ by numerical simulation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.52-57
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• 1996

Conductive Ceramic Matrix Composite(CMC) of TIC/Al2O3 and Metal Matrix Composite (MMC) of SiC/Al were experienced by the die sinking Electrical Discharge Machining(EDM) for different current and duty factor according to negative polarity. Inthis experimental study Material Removal Rate(MRR) maximum surface roughness four point bending stress distribution and Scanning Electron Microscopy(SEM) Photographs were analysed. the higher MRR was obtained for CMC than MMC but slowly decreased around duty factor of 0.67 for MMC and better surface morphology was found CMC than MMC. The SEM photographs of discharge traces for CMC showe uniform shape about 100 to 200${\mu}{\textrm}{m}$ in diameter but MMC showed irregular shape.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.577-588
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• 2020

A unified solution is presented for the buckling analysis of rectangular laminated composite plates with elastically restrained edges. The plate is subjected to biaxial in-plane compression, and the boundary conditions are simulated by employing uniform distribution of linear and rotational springs at all edges. The critical values of buckling loads and corresponding modes are calculated based on classical lamination theory and using the Ritz method. The deflection function is defined based on simple polynomials without any auxiliary function. The verifications of the current study are carried out with available combinations of classic boundary conditions in the literature. Through parametric study with a wide range of spring factors with some classical as well as some not classical boundary conditions, competency of the present model of boundary conditions is proved.