• Title/Summary/Keyword: O-jang

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UV/O3 Process Time Effect on Electrical Characteristics of Sol-gel Processed CuO Thin Film Transistor (UV/O3 조사 시간에 따른 Sol-gel 공정 기반 CuO 박막 트랜지스터의 전기적 특성 변화)

  • Lee, Sojeong;Jang, Bongho;Kim, Taegyun;Lee, Won-Yong;Jang, Jaewon
    • Journal of IKEEE
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    • v.22 no.1
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    • pp.1-5
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    • 2018
  • In this research, sol-gel processed CuO p-type thin film transistors were fabricated with copper (II) acetate monohydrate precursors. After $500^{\circ}C$ annealing process, the deposited thin films were fully converted into CuO. We investigated $UV/O_3$ process time effect on electrical characteristics of sol-gel processed CuO thin film transistors. After 600 sec $UV/O_3$ process, the fabricated CuO thin film transistor delivered field effect mobility in saturation regime of $5{\times}10^{-3}\;cm^2/V{\cdot}s$ and on/off current ratio of ${\sim}10^2$.

The Optical Properties of $TiO_2/Al/TiO_2$, $TiO_2/Cr/TiO_2$ Multi-layered Pearl-pigment films by DC, RF Magnetron Sputtering (DC, RF Magnetron Sputtering 공법을 이용한 다층 $TiO_2/Al/TiO_2$, $TiO_2/Cr/TiO_2$ 진주안료용 필름의 광학적 특성)

  • Lee, Nam-Il;Jang, Gun-Eik;Jeong, Jae-Il;Cho, Seong-Yoon;Jang, Gil-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.448-449
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    • 2006
  • For the possible applicative pearl pigment, multi-layered $TiO_2/Al/TiO_2$, $TiO_2/Cr/TiO_2$ thin film was deposited on glass substrate by using sputtering method. $TiO_2$ and Al or Cr was selected as a possible high and low refraction materials at the film interface respectively. Optical properties including color effect were systematically studied in terms of different film thickness and film layers by using spectrometer. In order to expect the experimental results, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. The film consisting of $TiO_2/Al/TiO_2$, $TiO_2/Cr/TiO_2$ layers show the wavelength range of 430 - 760nm, typically color ranges between bluish purple and red. It was confirmed that this experimental result was quite well matched with the experimental one.

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Effective Thermal Conductivities $Al_2O_3$ Nanoparticles Suspended in Water with Low Concentration (1%미만의 부피비를 가지는 알루미나 나노유체의 유효 열전도도)

  • Lee, Byeong-Ho;Kim, Jun-Ho;Kong, Yu-Chan;Jang, Seok-Pil;Koo, Ja-Ye
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2177-2181
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    • 2007
  • In this paper, effective thermal conductivities of water-based $Al_2O_3$-nanofluids with low concentration from 0.01 vol. % to 0.3 vol. % are experimentally obtained by transient hot wire method (THWM). The water-based $Al_2O_3$-nanofluids are manufactured by two-step method which is widely used. To examine suspension and dispersion characteristics of the water-based $Al_2O_3$-nanofluids, Zeta potential as well as transmission electron micrograph (TEM) is observed. We confirm the manufactured $Al_2O_3$-nanofluids have good suspension and dispersion. The effective thermal conductivities of the water-based $Al_2O_3$-nanofluids with low concentration are enhanced up to 1.64% compared with that of DI water at $21^{\circ}C$. In addition, experimental results are compared with theoretical results from Jang and Choi model.

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Thermal Characteristics of an N2O Catalytic Ignitor with Packed-bed Geometry (팩 베드 형상을 가지는 N2O 촉매 점화기의 열적현상)

  • You, Woo-Jun;Kim, Jin-Kon;Moon, Hee-Jang;Jang, Seok-Pil
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.4
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    • pp.398-404
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    • 2007
  • In this paper, thermal characteristics of a nitrous oxide ($N_2O$) catalytic reactor with packed-bed geometry are theoretically and numerically investigated. Several researchers experimentally presented that catalytic decomposition of $N_2O$ in a packed bed generates about 82kJ/mole in the exothermic reaction. Based on the results they have studied the catalytic decomposition of $N_2O$ in a packed bed to use it not only as a mono-propellant thrust for small satellites but also as an igniter system for hybrid rockets. So we aim to identify important parameters existing in an $N_2O$ packed-bed geometry, and to clarify its critical effect on thermal characteristics of the catalytic igniter using a porous medium approach.

Autogenous Expansion Models of Dam Concrete containing MgO (MgO를 혼입한 댐 콘크리트의 자기팽창 모델)

  • Choi, Seul-Woo;Oh, Sang-Hyuk;Lee, Kwang-Myong;Jang, Bong-Seok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.275-276
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    • 2010
  • In this study, using experimental results on the autogenous expansion of concrete containing MgO, autogenous expansion model which considers water-binder ratio, amount of MgO and curing temperature was suggested. The results predicted by autogenous expansion model agreed well with experiment results.

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