• Proceedings of the KSR Conference
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• 2004.06a
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• pp.352-357
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• 2004

In this study. the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated through a 2.5KW accelerated environmental aging tester. Environmental factors such as temperature. moisture, and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile, bending, and shear specimens those are warp direction and fill direction were used to investigate the effects of environmental factors on mechanical properties of the composites. The glass fabric $\sharp$650/AP300 was used for the fabrication of specimens. Mechanical degradations for tensile, bending and shear properties were evaluated through a UTM. Also. storage shear modulus. loss shear modulus, and tan $\delta$ were measured as a function of exposure times through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using II scanning electron microscope.

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.147-155
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• 1996

Optical properties of $TiO_2/M/Ag/M/TiO_2$ films have been changed with the diffusion barrier metal M. Optimum opticla properties of $TiO_2/M/Ag/M/TiO_2$ as the transparent heat mirror film, could be obtained with Ti among diffusion barrier metals of Ti, Cu, Zr and Al. $TiO_2/M/Ag/M/TiO_2$ film, which was fabricated by sputtering of 18 nm-thick $TiO_2$ and Ag, and 4nm-thick Ti, showed maximum transimittance of 89% at visible wavelength and infrared reflectance of 97% at wavelength of 3000 nm. Optical properties of this film was not degraded by Xenon-sunshine weather test for 240 hours. For specimens with barrier layers of Cu, Zr, and Al, degradation of optical properties by weather test was increased in a sequence of films with Cu, Zr, and Al barrier layers.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1276-1278
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• 1998

In this paper, aging characteristics of silicone rubber used for outdoor insulation have been investigated with regards to sunlight effect. For this purpose, silicone rubbers were aged under the artificial sunlight by use of xenon arc lamp(1500W) and various tests were performed such as tracking, breakdown, contact angle, stress, strain. And then, in order to elucidate the changes of material, analysis have been followed as follows; FT-IR, SEM and EDS. Regarding the effect of the sunlight, it was obs that the surface of test samples are severely da with decreased hydrophobicity, tracking resistan breakdown strength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.184-184
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• 2010

ITO의 전극 패턴에 따른 유기 광기전력 소자의 전기적 특성에 대해서 연구하였다. 소자의 구조는 ITO/PEDOT:PSS(90nm)/CuPc(20nm)/$C_{60}$(40nm)/LiF(0.5nm)/Al(100nm)이고, PEDOT:PSS는 스핀 코팅한 후 $120^{\circ}C$에서 20분간 건조시켰으며, 유기물은 열증착을 하여 제작하였다. ITO 전극의 패턴을 corss-bar type과 island type으로 하여 소자의 특성을 비교하였다. 광원은 500W xenon lamp를 사용하였고, optical density filter로 광원의 세기를 조절하였으며, AM 1.5G의 스펙트럼을 조사하였다. PEDOT:PSS 층을 사용함으로서 유기 광기전력 소자의 효율, 단락 전류, 그리고 개방 전압의 향상을 얻을 수 있었다. ITO 전극 패턴에 따른 광기전력 소자의 특성은 cross-bar type에 비하여 island type의 구조에서 유기 광기전력 소자의 효율이 34% 감소하였다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.190-194
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• 2003

Two different types of nondestructive evaluation (NDE) techniques were employed to investigate the tensile behavior of ceramic matrix composites (CMCs). Two NDE methods, ultrasonic testing (UT) and infrared (IR) thermography, were used to assess defects and/or damage evolution before and during mechanical testing. Prior to tensile testing, a UTC-scan and a xenon flash method were performed to obtain initial defect information in light of UT C-scans and thermal diffusivity maps, respectively. An IR camera was used for in-situ monitoring of progressive damages. The IR camera measured temperature changes during tensile testing. This paper has presented the feasibility of using NDE techniques to interpret structural performance of CMCs.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.52-55
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• 2004

Thermo-chromic Liquid Crystal(TLC) particles were used as temperature sensor for thermal fluid flow. $1K\times1K$ CCD color camera and Xenon Lamp(500W) were used for the visualization of a Hele-Shaw cell. The characteristic between the reflected colors from the TLC and their corresponding temperature shows strong non-linearity. A neural network known as having strong mapping capability for non-linearity is adopted to quantify the temperature field using the image of the flow. Improvements of color-to-temperature mapping was attained by using the local color luminance (Y) and hue (H) information as the inputs for the constructed neural network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.128-132
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• 1997

The conventional fire detection devices are operated after a processed fire phase, which are sensing only a high density of smoke level or high temperature heat. They are not so precision to detect a fire in the early phase to protect the facility from the fire. We need to develope a new high precision smoke detection system to keep expensive industial facilities most reliably from fire. A new optical precision smoke detection system was developed. It monitors very low level density of smoke psrticles in the air. It is operated continuously through many years without a stop or any malfunction. The developed precision smoke detection system will be installed in important industrial facilities,such as power plants, underground common tunnel,main control rooms,computer rooms etc.

• Proceedings of the Korean Reliability Society Conference
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• 2002.06a
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• pp.157-164
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• 2002

본 연구에서는 실생활에 응용되는 Chloroprene계 고무에 대하여 30개월 동안 옥외 폭로를 행하였으며 동시에 Xenon-arc Type의 촉진 내후성시험기를 이용하여 그에 따른 내후성의 변화를 평가하였다. 폭로기간에 따른 인장강도와 신장률의 변화를 측정하였고 폭로면의 표면층에 대하여 FT-IR과 SEM을 사용하여 화학적 특성 및 미세구조를 분석하였다. 태양복사와 습도에 노출된 고무의 표면은 매우 짧은 기간에 파괴되었고, 고무 내부에 존재하는 가교제들의 용출을 확인할 수 있었으며, 산소와의 결합으로 내부층보다 고무의 표면에서 더 많은 가수분해와 광분해가 이루어진다는 것을 확인할 수 있었다. 이와 같은 표면층의 변화와 파괴는 고무의 기계적 성질에도 의미 있는 영향을 주었다.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.824-829
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• 2007

Mechanical and thermal analysis properties of carbon fiber/epoxy composite for train carbody were evaluated by varying with environmental factors such as ultraviolet, temperature, and moisture. Accelerated environmental aging tester was utilized for this study. Testing temperature was set to $80^{\circ}C$ and ultraviolet was obtained through xenon-arc lamp. To consider moisture, water sprayed on specimen for 18 minutes every 2 hour. All the specimens were made of CF1263/Epoxy composite. Mechanical properties such as tensile, bending, and shear properties were evaluated through a material testing system. Also, thermal analysis properties such as storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured through dynamic mechanical analyzer. Finally surfaces of the composite exposed to environmental factors were examined using a scanning electron microscope. From experimental results, those properties of CF1263/Epoxy composite were shown to be slightly decreased due to environmental factors.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.758-764
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• 2016

Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth. A different hardening level under H and Xe irradiation was obtained and the discrepancies of displacement damage rate and ion species may be the probable reasons. It was observed that the hardness of Xe-irradiated specimens saturate at about 2 displacement/atom (dpa), whereas in the case of proton irradiation, the saturation hardness may be more than 7 dpa. This discrepancy may be due to the different damage distributions.