• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.145-148
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• 2005

Recently the construction of high-rise reinforced concrete building is progressively increased as the social demands. It is significantly important factors such as economy, the safety of structure, and the flexibility of internal space. Therefore new structural system is also required to be attained the reduction of story height, the flexibility and efficient use of space. The most suitable structural system is with the economy and flexibility, flat plate slab system in high-rise reinforced concrete building. In this research, it was focused in the improvement of shear performance in the flat plate system using high ductile fiber reinforced mortar. It was evaluated the shear performance in the critical region of slab-column connection. The flat plate system, designed by the high performance and safety, was developed as a new technique in the application of high-rise R/C building.

• Transactions of Materials Processing
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• v.17 no.5
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• pp.350-355
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• 2008

Currently, in the automotive industry, the efforts to reduce the manufacturing cost by changing the manufacturing process are continually performed. In this paper, we proposed a new manufacturing process, the roll bending process of a ring plate of automotive fuel tank instead of conventional press blanking process to reduce material loss and manufacturing cost. Finite element analysis was used to optimize the roll bending process to assure rectangular cross-section of the ring plate. Also, spring-back analysis after the roll bending process was performed and dimension of the bending die considering spring-back was analyzed. Finally, we verified a possibility for realization of the proposed method with prototypes.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.275-275
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• 2010

나노선의 합성을 위해 필요한 씨드는 기상증착에 경우 값비싼 공정 비용이 요구되지만 액상의 경우 저렴하고 공정이 단순하며 단시간에 공정이 용의하고 대면적이 가능하다는 장점을 가지고 있다. 우리는 zinc acetate, ethylene glycol monoethylethe(C3H8O2), Monoethanolamine을 일정한 비율로 혼합하여 ZnO 나노와이어 합성에 필요한 액상씨드를 만든 후 이것을 기판위에 증착하기 위해 수차례에 걸쳐 스핀코팅을 하였다. 스핀코팅후 퍼니스와 핫플레이트를 이용하여 Soft bake, Hard bake 공정을 통해 각각 열처리 한후 XRD 를 통한 결정성과 방향성 그리고 AFM을 통한 표면거칠기를 관찰하였고 또한 수열합성법을 통하여 제작한 씨드를 기반으로 하는 ZnO 나노와이어를 합성하여 각각의 열처리 조건에 따른 나노와이어의 특성변화를 관찰하였고 향후 나노기반 소자의 적용가능성을 확인하였다.

• Laser Solutions
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• v.14 no.2
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• pp.13-16
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• 2011

We fabricated the Fresnel zone plate using femtosecond laser lithography-assisted micro-machining, which is a combined process of nonlinear lithography and wet etching. We investigated the focusing properties by launching a 632.8nm wavelength He-Ne laser beam into the zone plate. The spot size of the primary focal point was $27{\mu}m$ and the intensity of focal point was 0.565W/$cm^2$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.162-163
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• 2014

Aluminum anodizing is a technique that can be formed pores well aligned various diameters. We were prepared CNFs using the polymer as carbon source using the AAO as a template. CNFs can be heat treated at $1400^{\circ}C$ and became soft carbon. It showed electrochemical behavior by Crystallization. In this experiment, I was observing the behavior as a anode material for LIC of CNFs having different diameters.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.35-39
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• 2009

Recently, the flat-plate structure is widely used because it has many advantages such as reduction of story height, long span etc than the RC rahmen structure. Furthermore, application of the flat-plate is on the increase because of flexible plan unlike wall structure. Long span have been at a disadvantage for vibration serviceability evaluation, however studies about vertical direction vibration of flat-plate structure has not been carried out. This study analysis the characteristics according to slab structure to make an experiment on vibration and floor impact noise for the flat-plate structure in construction performance laboratory in Kolon E&C R&D center, the flat-plate structure applied to the post-tension method, and the wall structure in apartment houses.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.126-127
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• 2007

AZ91D 마그네슘합금상에 MAO방법을 통한 산화막 성장에 관해 연구하였다. 주요 처리조성물은 NaOH, $Na_3\;C_6H_5O_7$, $Na_4\;P_2\;O_7$이며, 양극에 Mg 샘플을, 음극에 스텐레스 플레이트를 고정하여 설치후 인가전압 50V, 2분간에 걸쳐 Mg 표면에 Micro arc에 의한 산화막이 성장되었다. 산화막 측정 결과 20회 시행후 평균 15.5um 두께를 가졌으며, 막 성장후 표면은 균일하였으며, 밝은 갈색을 띄었다. 염수농도 5%의 염수분무테스트에서는 72시간 경과후에도 5%이내의 우수한 내부식성을 보였다.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.515-525
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• 2007

In this investigation, results of laboratory tests on four reinforced concrete flat plate interior connections with elongated rectangular column support which has been used widely in tall residential buildings are presented. The purpose of this study is to evaluate an effect of column aspect ratio (${\beta}_c={c_1}/{c_2}$=side length ratio of column section in the direction of lateral loading $(c_1)$ to the direction of perpendicular to $c_1$) on the hysteretic behavior under earthquake type loading. The aspect ratio of column section was taken as $0.5{\sim}3\;(c_1/c_2=1/2,\;1/1,\;2/1,\;3/1)$ and the column perimeter was held constant at 1200mm in order to achieve nominal vertical shear strength $(V_c)$ uniformly. Other design parameters such as flexural reinforcement ratio $(\rho)$ of the slab and concrete strength$(f_{ck})$ was kept constant as ${\rho}=1.0%$ and $f_{ck}=40MPa$, respectively. Gravity shear load $(V_g)$ was applied by 30 percent of nominal vertical shear strength $(0.3V_o)$ of the specimen. Experimental observations on punching failure pattern, peak lateral-load and story drift ratio at punching failure, stiffness degradation and energy dissipation in the hysteresis loop, and steel and concrete strain distributions near the column support were examined and discussed in accordance with different column aspect ratio. Eccentric shear stress model of ACI 318-05 was evaluated with experimental results. A fraction of transferring moment by shear and flexure in the design code was analyzed based on the test results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.17-20
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• 2005

This paper reported the temperature history of concrete placed at deck plate slab under cold climate condition by varying with surface insulating type. No curing sheet and simple insulation curing including non-woven fabric, double layer bubble sheet, the combination of double layer bubble sheet and non-woven fabric dropped temperature below zero within 24 hours, which caused frost damage at early age. On the other hand, the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam maintained minimum temperature above $4^{\circ}C\;and\;8^{\circ}C$, respectively. Based on core test results compressive strength of concrete with the combination of double layer bubble sheet and non-woven fabric and double layer bubble sheet and styrofoam was higher than those with other curing method due to good insulation effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.189-194
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• 2006

Ordered nanostructure materials have received attention due to their unique physical properties and potential applications in electronics, mechanics and optical devices. To actualize most of the proposed applications, it is quite important to obtain highly ordered nanostructure arrays. The well-aligned nanostructure can be achieved by synthesizing nanostructure material in the highly ordered template. To get well-aligned pore array and reduce process time, rapid thermal anneal by an IR lamp was employed in vacuum state at $500^{\circ}C$ for 2 hour. The pore array is comparable to a template annealed in vacuum furnace at $500^{\circ}C$ for 30 hours. The well-fabricated AAO template has the mean pore diameter of 70 nm, the barrier layer thickness of 25 nm, the pore depth of $9{\mu}m$, and the pore density of higher than $1.2{\times}10^{10}cm^{-2}$.