• Title/Summary/Keyword: Adsorption Mechanism

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Analysis of Gas Response Characteristics of Maleate Organic Ultra-thin Films (말레에이트계 유기초박막의 가스 반응 특성 분석)

  • Choe, Yong-Seong;Kim, Jeong-Myeong;Kim, Do-Gyun;Gwon, Yeong-Su
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.6
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    • pp.442-450
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    • 1999
  • In this paper, we have fabricated Langmuir-Blodgett(LB) films by LB technique and evaluated the deposited status of LB films by UV-vis absorbance. It was found thatthe thickness of LB films per a layer are $27~30[{\AA}]$ by ellipsometry. The responeses between LB films and organic gases were investigated using by I-V characteristics of LB films and F-R diagram of quartz crystal. The response orders between LB films and organic gases observed by I-V characteristics were as following ; chloroform, methanol, acetone and ethanol in the order of their short chain length. The response mechanism between LB films and organic gases observed by F-R diagram of quartz crystal could be modeled on adsorption at surface, penetration, desorption at surface and inside.

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A Study on the Reaction Mechanism of Selective Epitaxial Growth in $SiH_2Cl_2-H_2-HCl$ System ($SiH_2Cl_2-H_2-HCl$ 시스템에서의 실리콘 선택적 성장에 대한 표면 반응메커니즘 고찰)

  • Kim, Bong-Soo;Han, Seung-Oh;Pak, James Jung-Ho
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1288-1290
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    • 1998
  • Three most dominant reactions are adsorption, movement, and desorption of $SiCl_2$ on silicon surface. $SiCl_2$ plays a key role in these dominant reactions. In this paper, surface reactions of $SiH_2Cl_2-H_2-HCl$ system are investigated and few dominant reactions were identified. An equation for Si net growth rate is derived from the analysis of these reactions and it is compared with experimental results of Bolem and Classen.

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A Review of Corrosion and Hydrogen Diffusion Behaviors of High Strength Pipe Steel in Sour Environment

  • Kim, Sung Jin;Kim, Kyoo Young
    • Journal of Welding and Joining
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    • v.32 no.5
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    • pp.13-20
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    • 2014
  • A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

A Study on the Electrical Properties of Plasma Polymerized MST Films (플라즈마 중합된 MST 박막의 전기적 특성에 관한 연구)

  • Kim, S.O.;Park, B.K.;Han, S.O.;Park, J.K.;Park, G.B.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1636-1638
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    • 1996
  • MMA-Styrene-Tetramethyltin(MST) thin films were fabricated by plasma polymerization method, and their electrical properties were confirmed by IR and GPC. The electrical conductivity increased with increasing temperature, and the adsorption current hardly appeared. The high-field electrical conduction mechanism is the electronic one such as schottky, and the activation energy is about 1.1 eV.

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Absorption Ratio and Density Properties According to Absorbent Type Based on Magnesium Oxide Matrix (산화마그네슘 경화체 기반 흡착재 종류에 따른 밀도 및 흡수율 특성)

  • Gwon, Oh-Han;Pyeon, Su-Jung;Lim, Hyun-Ung;Kyung, In-soo;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.182-183
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    • 2017
  • This research identifies radon gas absorption mechanism by adsorption materials, replacing gypsum board with radon emissions, the density and absorption rates of magnesium were carried out using vermiculite, anthracite, powdered active carbon, bentonite, illite, diatomite as a basic study on the fire resistance type of radon Gas reduction type with absorption and decomposition. As a result of the experiment, diatomite showed the lowest density, and the highestt value was the highest. For the absorption rate, bentonite showed the highest absorption rate, and the anthracite showed the lowest absorption rate.

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Vacuum Dependency of Si, Co Slicide and Mo Silicide FEAs

  • Lee, Jong-Duk;Shim, Byung-Chang;Park, Byung-Gook;Uh, Hyung-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.685-688
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    • 2002
  • In this paper, it is reported that the anode current changes at the constantly applied gate voltages and the current-voltage (I-V) characteristics of Si, Co silicide and Mo silicide field emitter arrays (FEAs) depending on vacuum level from a $10^{-9}$ torr to a $10^{-6}$ torr. The mechanism of the robustness of anode current degradation of Mo silicide FEAs under poor vacuum conditions can be explained by the model of tolerance for the oxygen adsorption and oxidation at the silicide surface. Also, we present the changes of emitting area and work function of the emitters according to vacuum level.

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Transport of Metal Ions Through the Crosslinked Chitosan Membrane (가교 Chitosan막에 의한 금속 이온의 투과 특성)

  • Kim, Chong-Bae
    • Applied Chemistry for Engineering
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    • v.4 no.2
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    • pp.416-422
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    • 1993
  • In order to prepare high performance polymeric membrane, the crosslinked chitosan(C. Chitosan)membrane was prepared, the transport and the selective separation of the metal ions through the membrane were investigated. It was observed that the transport rates of the metal ions through the membrane increased according to the decreasing of the initial pH in downstream solution. Proton pump mechanism for this transport phenomenon was suggested. The transport selectivity is dependent on the selective adsorption resulting from the complex formation of chitosan with each metal ion. The separatin factor(${\alpha}_{Cu}{^{2+}}$) for the membrane was 9.5.

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Numerical Modeling of an Inductively Coupled Plasma Based Remote Source for a Low Damage Etch Back System

  • Joo, Junghoon
    • Applied Science and Convergence Technology
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    • v.23 no.4
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    • pp.169-178
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    • 2014
  • Fluid model based numerical analysis is done to simulate a low damage etch back system for 20 nm scale semiconductor fabrication. Etch back should be done conformally with very high material selectivity. One possible mechanism is three steps: reactive radical generation, adsorption and thermal desorption. In this study, plasma generation and transport steps are analyzed by a commercial plasma modeling software package, CFD-ACE+. Ar + $CF_4$ ICP was used as a model and the effect of reactive gas inlet position was investigated in 2D and 3D. At 200~300 mTorr of gas pressure, separated gas inlet scheme is analyzed to work well and generated higher density of F and $F_2$ radicals in the lower chamber region while suppressing ions reach to the wafer by a double layer conducting barrier.

Reaction of Methanol and Methyl Iodide on ZnO(0001) and ZnO(11-20) Single Crystal Surfaces

  • Doh, Won-Hui;Roy, Probir Chandra;Kim, Chang-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.214-214
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    • 2011
  • The adsorption and reactions of methanol and methyl iodide on ZnO(0001) and ZnO(11-20) single crystal surfaces have been investigated using the temperature programmed desorption (TPD) technique. The interaction of methanol and methyl iodide with ZnO is stronger on the polar ZnO(0001) surface than the non-polar ZnO(11-20) surface. On ZnO(0001), methanol is decomposed to produce formaldehyde and hydrogen. Two desorption features of formaldehyde and hydrogen are observed at around 500 and 580 K. The interaction of methanol and pre-adsorbed hydrogen has been also investigated. The reaction mechanism of methanol on ZnO will be proposed.

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Investigation of the Biodegradable Mechanism of Pure Magnesium Using Electrochemical Impedance Spectroscopy Technique

  • Kim, Woo-Cheol;Kim, Seon-Hong;Kim, Jung-Gu;Kim, Young-Yul
    • Corrosion Science and Technology
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    • v.15 no.2
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    • pp.43-53
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    • 2016
  • In this study, electrochemical impedance spectroscopy (EIS) was used to examine the changes in the electrochemical properties of biodegradable pure magnesium implanted into Sprague-Dawley rats for three days. The in vivo test results were compared with those of the in vitro tests carried out in Hank's, dilute saline and simulated body fluid (SBF) solutions. The in vitro corrosion rates were 20~1700 fold higher, as compared to the in vivo corrosion rates. This discrepancy is caused by biomolecule adsorption on the surface, which prevents the transport of water into the magnesium surface on in vivo testing. Among the in vitro experimental conditions, the corrosion rate in SBF solution had the least difference from the in vivo implanted specimen.