• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.588-592
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• 2004

Effect of the UO$_2$ powder characteristic changes by dynamic milling method on the density was investigated. particle size decreased and its shape was changed from irregular to round form with increasing milling time (0∼8 h), while its specific surface area and O/U ratio increased. It was shown that the sintered density decreased, while green density increased with these powder characteristic changes. It could be considered that this decrement was affected by increased O/U ratio of the UO$_2$ powder during dynamic milling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1967-1974
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• 2005

The butterfly valve has been used to control a flow effectively in the industrial because of its lightweight, simple structure and the rapidity of its manipulation. However, it is difficult to have the existing structural optimization using field analysis from CFD to structure analysis when the structure is influenced by fluid. This paper is evaluated the specificity to get the flow characteristic and stability of the butterfly valve using FEM and CFD. Also, it accomplished the shape optimization design using the orthogonal arrangement and characteristic function. Research result, a few experiments showed the optimal results of three dimensional structures to be multi-objective.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.54-60
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• 2013

Numerical analysis of the radiant heat characteristic around heatsink according to arrangement and shape of fin on 60W-LED lamp is conducted in this study. In the case of top blow blowing from upper side on LED lamp, there is just little difference in cooling characteristics according to the height of fin. On the other hand, the fin arranged side by side has the advantage of heat transfer enhancement by comparing with zig-zag type because it leads to more loss of flow. In case of making fin round to increase the amount of heat transfer, designing arrangement with the minimized loss of flow has the advantage of characteristic.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.108-117
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• 2005

In modern industrial society, many kinds of valves have been used to control fluid flow. For the optimization of a ball valve, a quarter of spherical ball was modeled and evaluated. However, there is a difficulty in the application of the optimization technique because of the complexity of the fluid and the restriction of analysis. Therefore, in this study, it is performed to evaluate the stability of an initial model using FEM(Finite Element Method) and CFD. In addition, a shape optimization design of the valve is accomplished using an orthogonal arrangement and characteristic functions. From the result, a new design method is represented that could overcome the time and space restriction in structural design, such as the divided ball valve with less experiment.

• Journal of Ocean Engineering and Technology
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• v.19 no.3
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• pp.59-65
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• 2005

In today's industry, the butterfly valve has been used to control a flow effectively. However, it is difficult to have the existing structural optimization using field analysis from CFD to structure analysis when the structure is influenced by fluid. Therefore, an initial model of this study is to evaluate the stability of the valve using FEM and CFD. And, it selected variable using initial analysis results. Also, it accomplished the shape optimization design using the orthogonal arrangement and characteristic function. Research result, a few experiments showed the optimal results of there dimensional structures to be multi-objective.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.314-318
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• 2005

The effect of reaction parameters in the characteristic of $Pb(Zr_{0.52}Ti_{0.48})O_3$ (below nominal PZT) powders by SHS was investigated in this study. In the preparation of PZT, the effect of starting material contents, pressure, additive on phase fraction and morphology was investigated respectively. The optimum condition of PZT powders were prepared by SHS is $0.37Pb_3O_4+0.52ZrO_2+0.48TiO_2+0.35KClO_3+0.5C,\;(P_{Ar}= 50 atm)$. The PZT powder synthesized in this condition had an spherical shape and the particle size of 0.8$\mu$m.

• The KSFM Journal of Fluid Machinery
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• v.11 no.2
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• pp.38-45
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• 2008

This study presents a numerical procedure to optimize the compressor design to increase the surge margin of compressor with response surface method (RSM). The Box-Behnken design method is used to reduce the number of calculation for fitting the second-order response surface. In order to consider the increase of surge margin during numerical optimization without any calculation at the surge point, the slope of compressor characteristic curve at the design point is suggested as an objective function in the present optimization problem. Mean line performance analysis method is used to get the design and off-design characteristic curves of centrifugal compressor. The impeller exit angle, impeller exit height and impeller radius are chosen as design variables. The optimum shapes show the increase of surge margin for the surge margin optimization and increase of efficiency for the efficiency optimization in comparison with an initial shape.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1069-1070
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• 2007

In this paper, a new stator shape for axial flux motor was proposed. It consists of tooth and back-yoke laminated and be assembled with each other. The method assembling together has a significant characteristic. It is different direction of lamination between core and back-yoke. This paper shows analysis method considering the lamination direction and analyze characteristic of axial flux motor with stator proposed using 3D finite element method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.870-871
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• 2009

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.39-39
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• 2010

낮은 에너지를 이용하여 상대론적 영역에서 동작하는 마이크로파 출력장치를 연구하였다 그에 따른 후진파 발진기는 대전력 마이크로파를 발생시키는 장치로서 연구하였으며 관내에 전자빔을 입사시킴으로서 발진이 일어나 출력을 발생 시킨다.