• Title/Summary/Keyword: Atomic vapor

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Effect of radiation model on simulation of water vapor - hydrogen premixed flame using flamelet combustion model in OpenFOAM

  • Kim, Sangmin;Kim, Jongtae
    • Nuclear Engineering and Technology
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    • v.54 no.4
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    • pp.1321-1335
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    • 2022
  • This study was conducted to investigate the effect of absorption coefficient models on the P1 radiation model for a premixed hydrogen flame containing the water vapor. A CFD combustion simulation analysis was performed using XiFoam, one of the open-source CFD solvers in OpenFOAM. The solver using the flamelet combustion model has been modified to implement radiative heat transfer. The absorption coefficient models used in this study the grey-mean model and constant model, and for comparison, case without radiation was added. This CFD simulation study consisted of benchmarking the THAI HD-15 and HD-22 experiments. The difference between the two tests is the inclusion of water vapor in the condition before ignition. In the case of the HD-22 experiment containing water vapor in the initial condition, the simulation results show that the grey-mean absorption coefficient model has a strong influence on the temperature decrease of the flame and on the change in pressure inside the vessel.

Vapor Deposition Techniques for Synthesis of Two-Dimensional Transition Metal Dichalcogenides

  • Song, Jeong-Gyu;Park, Kyunam;Park, Jusang;Kim, Hyungjun
    • Applied Microscopy
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    • v.45 no.3
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    • pp.119-125
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    • 2015
  • Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted significant attention due to their unique and exotic properties attributed to their low dimensionality. In particular, semiconducting 2D TMDCs such as $MoS_2$, $WS_2$, $MoSe_2$, and $WSe_2$ have been demonstrated to be feasible for various advanced electronic and optical applications. In these regards, process to synthesize high quality 2D TMDCs layers with high reliability, wafer-scale uniformity, controllable layer number and excellent electronic properties is essential in order to use 2D TMDCs in practical applications. Vapor deposition techniques, such as physical vapor deposition, chemical vapor deposition and atomic layer deposition, could be promising processes to produce high quality 2D TMDCs due to high purity, thickness controllability and thickness uniformity. In this article, we briefly review recent research trend on vapor deposition techniques to synthesize 2D TMDCs.

Spectroscopic studies of the high-pressure di-atomic sulfur vapor excited in an optical cavity by microwave discharges (마이크로파 방전에 의한 광학적 공동 안에서 고압 2-원자 황 증71의 분광학적 특성 연구)

  • 김진중;고정태;원동호;홍성호;김정원
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.114-115
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    • 2002
  • 마이크로파 방전에 의한 고압 2-원자 황증기 (high-pressure di-atomic sulfur vapor)는 고효율(high luminous efficacy) 및 고연색성 (high color rendering index)의 백색 광원 (source of white light)으로 높이 평가되고 있다 [1]. 소위 무전극 황전등 (elec출odeless sulfur lamp, ESL)으로 알려진 이 발광원은 최고 효율이 173 lm/w 까지 시연되어 알려진 모든 인조 광원 중에서 가장 높은 효율을 보인 혁신적인 광원이다 [2]. (중략)

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Evaluation of Granite Melting Technique for Deep Borehole Sealing (심부시추공 밀봉을 위한 화강암 용융거동 평가)

  • Lee, Minsoo;Lee, Jongyoul;Ji, Sung-Hoon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.4
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    • pp.479-490
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    • 2018
  • The granite melting concept, which was suggested by Gibb's group for the closing of a deep borehole, was experimentally checked for KURT granite. The granite melting experiments were performed in two pressure conditions of atmospheric melting with certain inorganic additives and high pressure melting formed by water vaporization. The results of atmospheric tests showed that KURT granite started to melt at a lower temperature of $1,000^{\circ}C$ with NaOH addition and that needle shaped crystals were formed around partially melted crystals. In high pressure tests, vapor pressure was increased by adding water with maximum pressure of about 400 bars. KURT granite was partially melted at $1,000^{\circ}C$ when vapor pressure was low. However, it was not melted at vapor pressures higher than 200 bars. Therefore, it was determined that high pressure with a small amount of water vapor more effectively decreased the melting point of granite. Meanwhile, high temperature and high pressure vapor caused severe corrosion of the reactor wall.

An Experimental Study on the Direct Contamination Pathway of Elemental iodine Vapor $(I_2)$ for Rice Plants (벼에 대한 원소상 요오드 증기$(I_2)$의 직접오염경로 해석 실험)

  • Choi, Y.H.;Lim, K.M.;Lee, C.M.;Park, H.G.;Park, D.W.;Choi, G.S.;Choi, H.J.;Lee, H.S.;Lee, C.W.
    • Journal of Radiation Protection and Research
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    • v.29 no.3
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    • pp.165-172
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    • 2004
  • Rice plants were exposed to $I_2$ vapor for 80 min at different growth stages in an exposure box to investigate the parameters concerning direct plant contamination. Deposition velocity $(m\;s^{-1})$ of the $I_2$ vapor for the straws was in the range of $1.4{\times}10^{-5}-1.3{\times}10^{-4}$ depending on the exposure time, being comparatively low during the earlier part of the plant growth. Ear deposition velocity was in the range of $2.5{\times}10^{-5}-6.7{\times}10^{-5}$. Whole-plant deposition velocity was in the range of $1.4{\times}10^{-5}-1.8{\times}10^{-4}$ with the highest from the exposure performed on Aug. 18 (7 d after the start of heading). The time-dependent variation generally decreased when the deposition velocity was normalized to the biomass density No noteworthy tendency in the deposition velocity was observed with regard to the temperature, sunlight and humidity. Translocation factor for the hulled seeds was $3.3{\times}10^{-5}-4.7{\times}10^{-4}$ with the highest from the Aug. 23 exposure. It was found that a leaf deposition even before the ear emergence resulted in a considerable seed translocation.

Fabrication of NiO buffer film on textured Ni substrate for YBCO coated conductor (Textured Ni 기판 위에 YBCO coated conductor 모재용 NiO 완충층 제조)

  • Sun, Jong-Won;Kim, Hyoung-Seop;Jung, Choon-Ghwan;Lee, Hee-Gyoun
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.125-129
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    • 2001
  • NiO buffer layers were deposited on texture Ni tapes fur YBCO coated conductors by MOCVD(metal organic chemical vapor deposition) method, using a single solution source. Variables were deposition temperature and flow rate of $0_2$carrier gas. At higher temperatures, The NiO(111) texture was well developed, but the NiO(200) texture was developed at low temperatures. The best result was obtained at the deposition temperature of$ 470^{\circ}C$ and the gas flow rate of 200 sccm. FWHM value of $\omega$-scan fur NiO(200) of the film and $\Phi$-scan for NiO(111) of the film was $4.2^{\circ}$ and $7^{\circ}$, respectively.

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