• Journal of Korea Foundry Society
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• v.28 no.2
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• pp.79-84
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• 2008

Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

• Korean Journal of Materials Research
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• v.19 no.5
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• pp.270-275
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• 2009

Lotus-type porous nickel with cylindrical pores was fabricated by unidirectional solidification under an Ar gas atmosphere using the thermal decomposition method of the compounds such as sodium hydroxide, calcium hydroxide, calcium carbonate, and titanium hydride. The decomposed gas does form the pores in liquid nickel, and then, the pores become the cylindrical pores during unidirectional solidification. The decomposed particles from the compounds do play a rule on nucleation sites of the pores. The behavior of pore growth was controlled by atmosphere pressure, which can be explained by Boyle's law. The porosity and pore size decreased with increasing Ar gas pressure when the pores contain hydrogen gas decomposed from calcium and sodium hydroxide and titanium hydride, ; however it they did not change when the pores contain containing carbon dioxide decomposed from calcium carbonate. These results indicate that nickel does not have the solubility of carbon dioxide. Lotus-type porous metals can be easily fabricated by the thermal decomposition method, which is superior to the conventional fabrication method used to pressurized gas atmospheres.

• Membrane Journal
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• v.22 no.5
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• pp.285-300
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• 2012

Vanadium redox flow battery is believed to be one of important energy storage technologies, because it has many advantages, including long cycle life, high energy efficiency, low cost of maintenance, and environmental friendship. As one of the key components of vanadium redox flow battery system, an ion exchange membrane is required to prevent cross-mixing of the positive and negative electrolytes while allowing ionic continuity. However, ion exchange membrane such as Nafion using in VRBs still face some challenges in meeting performance and cost requirements for broad penetration. Therefore, to resolve these problems, developed various ion exchange membranes are investigated and compared with Nafion membranes in terms of their performance in vanadium redox flow battery.

• Membrane Journal
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• v.21 no.4
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• pp.307-320
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• 2011

Polymeric gas separation membrane is the fastest growing field in membrane separation process. Polymeric gas separation membrane process is competitive compare to cryogenic process and pressure swing adsorption process. Aromatic polymer materials such as polysulfones, polypheneylene oxides, polycarbonates and polyimides have been used for gas separation. Recently, glassy polymer likes polyimide in aromatic polymers has been developed for achievement of high selectivity and permeability coefficients. The accurate understanding on a type and structure of polymer material is very important, because the factor that polymer material affect gas separation property. In the study, trend and the development direction on synthesis and permeation properties of polyimide is confirmed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.555-556
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• 2014

ICT 기술이 발전하면서 놀이동산 같은 체험이 필요한 것들까지도 디지털화 하는 것이 가능하게 되었다. 최근에는 가상현실 기술을 이용하여 컴퓨터 시뮬레이션으로 창출된 3차원 가상공간에서 사용자의 오감 경험을 확장하고 공유함으로서, 기존의 놀이동산 게임에서 느낄 수 없는 3차원 현실세계와 유사한 경험을 추구할 수 있게 되었다. 따라서 본 논문에서는 가상현실을 이용하여 유저와 상호작용하고, 사용자에게 현실과 유사한 즐거움을 줄 수 있는 놀이동산 테마파크 게임을 개발하였다. 본 연구의 놀이동산 테마파크 게임은 Eon Studio 개발툴과 JavaScript를 이용하여 구현되었으며, Eon I-CUBE안에서 1인칭 주인공 시점으로 게임을 진행하도록 하였다. 또한 유저가 선택한 스토리 중심으로 놀이동산 테마파크를 구현하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.547-548
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• 2014

ICT 기술발전으로 웨어러블 디바이스(wearable device)와 증강현실(augmented reality: AR) 및 가상현실(virtual reality: VR)등은 차세대 게임 산업에 새로운 재미와 가치를 부여할 기술로 주목받고 있다. 특히 가상현실 기술은 몰입(immersion)이라는 경험적 속성을 가지고 있어, 컴퓨터 시뮬레이션으로 창출된 3차원 가상공간으로 사용자의 오감 경험을 확장하고 공유함으로서 공간적, 물리적 제약에 의해 현실 세계에서는 직접 경험하지 못하는 상황을 간접 체험할 수 있도록 한다. 따라서 본 논문에서는 가상증강현실을 이용하여 유저와 상호작용하고, 사용자에게 현실적인 공포감을 줄 수 있도록 하는 오감 체험 공포 시뮬레이션을 개발하였다. 이 체험 시뮬레이션 게임은 Eon Studio 개발툴과 JavaScript를 이용하여 구현되었으며, Eon I-CUBE안에서 1인칭 주인공 시점으로 게임을 진행하도록 하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.118-122
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• 2008

• Journal of the Chungcheong Mathematical Society
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• v.35 no.4
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• pp.307-313
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• 2022

In this paper, we will consider the periodic stationary Stokes equations on Rⁿ. For the cube of the period, we set Ω = ∏ⁿ_i=1(0, L_i). And we will study the stability of the solutions on various functional spaces, for the Stokes equations on Rⁿ.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.6
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• pp.275-282
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• 2018

Two different modes of rolling were applied to control the texture development in tantalum sheet. In the conventional uni-directional rolling, the typical rolling textures of a body-centered cubic metal which was primarily composed of <110>//(rolling direction) was developed. In a cross rolling where the specimen was rotated by $90^{\circ}$ between each pass, the rotated cube components, i.e. {100}<011> were greatly reinforced. The prediction of lattice rotation by the full-constraint Taylor model showed that the high stability and the symmetry of the rotated cube components caused their strengthening in cross-rolling. The two specimens were heated to $1,100^{\circ}C$ at $9^{\circ}C/min$and held for 1 hour for annealing, then cooled to room temperature in atmosphere. In spite of the significant difference in the deformation textures, the annealing textures were very similar. They developed strong <111>//(plane normal) components with negligible intensity at the rotated cube components, which was attributed to the negligible capability of the latter components to provide effective recrystallized grains.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.113.2-113.2
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• 2007