• Title/Summary/Keyword: low temperature irradiation

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The Effects of Environmental Factors on Degradation and Hydrophobicity Recovery Characteristics in RTV Silicone Rubber (RTV 실리콘 고무의 열화 및 발수성 회복 특성에 미치는 환경인자의 영향)

  • Heo, Chang-Su;Yeon, Bok-Hui;Jo, Hyeon-Uk;Hwang, Myeong-Geun
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.6
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    • pp.462-468
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    • 1999
  • Room temperature vulcanizing (RTV) silicone rubber has been widely used to coat porcelain insulators to render water repellency to prevent formation of water film on the surface and thus to suppress the leakage current and consequently flashover. However, the electrical property and the hydrophobicity of RTV silicone rubber coating under outdoor condition may be influenced by many environmental factors. In this studyvarious treatments, such as salt-fog, salt water immerging and UV irradiation were applied to the samples to investigate the change of the electrical property and hydrophobicity. As a result the leakage current increased and contact angle decreased asthe degradation time is longer. But the degraded RTV silicone rubber has recovered its hydrophobicity during the drying time in ambient condition because LMW(Low Molecular Weight) silicone fluid diffused from the bulk to the surface.

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Effect of Stereoregularity on the Properties of Syndiotacticity-Rich Ultrahigh Molecular Weight Poly(vinyl alcohol)/Dimethylsu1foxide/Water Gel

  • Park, Jin-Hyun;Lyoo, Won-Seok;Ko, Sohk-Won
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.13-16
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    • 1998
  • Poly(vinyl alcohol) (PVA) gels are easily formed via physical pathway. Most PVA solutions including PVA/water solution are well known to form thermally reversible gels at low temperature but these gels showed poor mechanical properties. In order to overcome this weak point, transparent crosslinked PVA hydrogels were prepared by electron beam irradiation or by chemical process with crosslinking agents or additives. (omitted)

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Estimation of Heat Losses From the Receivers for Solar Energy Collecting System of Korea Institute of Energy Research

  • Ryu, Siyoul;Seo, Taebeom
    • Journal of Mechanical Science and Technology
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    • v.14 no.12
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    • pp.1403-1411
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    • 2000
  • Heat losses from the receivers for a dish-type solar energy collecting system constructed at Korea Institute of Energy Research are analyzed. The Stine and McDonald's model is used to estimate the convection loss. The Net Radiation method and the Monte-Carlo method are used to calculate the radiation heat transfer rate from the inside surface of the receiver to the surroundings. Two different receivers are suggested here and the performances of the receivers are estimated and compared with each other based on the prediction of the amount of heat losses from the receivers. The effects of the receiver shape and the radiation properties of the surface on the thermal performance are investigated. The performance of Receiver I is better than that of Receiver II, and the amount of solar irradiation that is not captured by the captured by the receiver after being reflected by the concentrator becomes significant if the temperature of the working fluid is low.

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Sequential Lateral Solidification Process for Fabrication of Crystalline Silicon Thin Film Transistor (단결정 실리콘 TFT 제작을 위한 SLS 공정)

  • Lee, Youn-Jae;Pak, Jung-Ho
    • Proceedings of the KIEE Conference
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    • 2000.11c
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    • pp.461-463
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    • 2000
  • This paper presents a low temperature excimer-laser-crystallization that produces directionally solidified microstructure in Si thin films. The process involves (1) a complete melting of selected area via irradiation through a patterned mask. and (2) a precisely controlled pulse translation of the sample with respect to the mask over a distance shorter than the superlateral growth(SLG) distance. (3) lateral growth extended over a number of iterative steps. Grains that grow continuously to the vertical direction were demonstrated. We discuss sequential lateral solidification principle, experiment.

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Advances in excimer laser annealing for LTPS manufacturing

  • Herbst, Ludolf;Simon, Frank;Paetzel, Rainer;Chung, Suk-Hwan;Shida, Junichi
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1032-1035
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    • 2009
  • Several different production technologies for Low-Temperature Poly-Silicon (LTPS) have been proposed over the last years. However, finally the progress in Excimer-laser-based crystallization has lead to the best cost-to-performance ratio of LTPS manufacturing for use in active-matrix-based displays. In this paper, we report on recent and significant technical advances in light sources, optical beam deliveries and beam irradiation systems targeted at enabling ultra-uniform mura-free LTPS active-matrix backplanes while simultaneously lowering production costs and increasing throughput.

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Application of 532 nm YAG-Laser Annealing to Crystallization of Amorphous Si Thin Films Deposited on Glass Substrates

  • Lee, Jong-Won;So, Byung-Soo;Chung, Ha-Seung;Hwang, Jin-Ha
    • Korean Journal of Materials Research
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    • v.18 no.3
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    • pp.113-116
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    • 2008
  • A 532 nm Nd-YAG laser was applied to crystallize amorphous Si thin films in order to evaluate the applicability of a Nd-YAG laser to low-temperature polycrystalline Si technology. The irradiation of a green laser was controlled during the crystallization of amorphous Si thin films deposited onto glass substrates in a sophisticated process. Raman spectroscopy and UV-Visible spectrophotometry were employed to quantify the degree of crystallization in the Si thin films in terms of its optical transmission and vibrational characteristics. The effectiveness of the Nd-YAG laser is suggested as a feasible alternative that is capable of crystallizing the amorphous Si thin films.

A study on radiation degradation of LDPE by using ESR (ESR을 이용한 저밀도 폴리에틸렌의 방사선 열화에 관한 연구)

  • Kim, Ki-Yup;Kim, Jin-Ah;Lee, Chung;Kim, Pyeong-Jong;Ryu, Boo-Hyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.473-476
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    • 2004
  • This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated using a $Co^{60}\;\gamma-ray$ and ray up to 800 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, free radical measurement of LDPE has established by electron spin resonance(ESR). Then, each sample was stored for 2 weeks. ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and changed from alkyl, allyl radical to peroxy radical with time.

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Fabrication of Ultra Low Temperature Poly crystalline Silicon Thin-Film Transistors on a Plastic Substrate (고분자 기판 상에 제작된 극저온 다결정 실리콘 박막 트랜지스터에 관한 연구)

  • Kim, Yong-Hoon;Kim, Won-Keun;Moon, Dae-Gyu;Han, Jeong-In
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.445-446
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    • 2005
  • This letter reports the fabrication of polycrystalline silicon thin-film transistors (poly-Si TFT) on flexible plastic substrates using amorphous silicon (a-Si) precursor films by sputter deposition. The a-Si films were deposited with mixture gas of argon and helium to minimize the argon incorporation into the film. The precursor films were then laser crystallized using XeCl excimer laser irradiation and a four-mask-processed poly-Si TFTs were fabricated with fully self-aligned top gate structure.

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Characteristics of low temperature poly-Si thin film transistor using excimer laser annealing (엑시머 레이저를 이용한 저온 다결정 실리콘 박막 트랜지스터의 특성)

  • Kang, Soo-Hee;Kim, Yong-Hoon;Han, Jin-Woo;Seo, Dae-Shik;Han, Jeong-In
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.430-431
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    • 2006
  • This letter reports the fabrication of polycrystalline silicon thin-film transistors (poly-Si TFT) on flexible plastic substrates using amorphous silicon (a-Si) precursor films by sputter deposition. The a-Si films were deposited with mixture gas of argon and helium to minimize the argon incorporation into the film. The precursor films were then laser crystallized using XeCl excimer laser irradiation and a four-mask-processed poly-Si TFTs were fabricated with fully self-aligned top gate structure.

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Property of Spin-sprayed ZnO Film on PC Substrate (스핀 스프레이법으로 PC 기판에 제작한 산화아연 박막의 특성)

  • Hoong, Jeongsoo;Matsushita, Nobuhiro;Katsumata, Ken-ichi;Park, Yongseo;Kim, Kyunghwan
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.3
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    • pp.27-30
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    • 2018
  • In this study, ZnO film was deposited on polycarbonate substrate by spin-spray method at low substrate temperature of $85^{\circ}C$. Surface morphology of ZnO films was changed by adding citrate from rod to dense structure. As-deposited ZnO film indicated high transmittance above 80%. In case of the resistivity, as-deposited ZnO film had high resistivity due to the existence of organic substance in the film. However, organic substance was removed and resistivity was decreased to $3.9{\times}10^{-2}{\Omega}{\cdot}cm$, after UV irradiation.