• Title/Summary/Keyword: In-situ

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Investigation of pretilt generation by UV light irradiation during imidization of polyimide (폴리이미드 소성 시에 UV 광조사를 이용한 프리틸트 발생에 대한 연구)

  • 서대식;김형규
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.1
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    • pp.75-79
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    • 2000
  • In this study, we investigated the pretilt angle generation and liquid crystal (LC) alignment by ultravi-olet (UV) light irradiation during imidization of polymide. The generated pretilt angle of nematic (N) LC by using the in-situ photo-alignment method was smaller than that of the conventional UV photo-alignment method. Also, generated pretilt angle of NLC tends to increase by annealing. In case of using the polymer(AL-3046), we found that the in-situ Uv photo-alignment method has higher thermal stability of LC alignment, but it has a disadvantage to control pretilt angle.

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Investigation of growth of ZnO thin films via RE sputtering system and in-situ post annealing

  • Jin, Hu-Jie;Lim, Keun-Young;So, Byung-Moon;Park, Choon-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.61-62
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    • 2005
  • The present article deals with in situ post annealing of ZnO in sputtering system. The ZnO thin films were grown at low temperature of $100^{\circ}C$ and at working pressure of 15 mTorr with RF magnetron sputtering. Having been gown, ZnO thin films were annealed in situ at different temperatures, at annealing ambient pressure of 15 mTorr and in ambients of oxygen and argon respectively. Through analyses of XRDs, it is can be concluded that the crystallinity of annealed ZnO thin films becomes much better than that of as-grown ZnO thin film.

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Biobarrier를 이용한 유기오염물질의 생물학적분해모의를 위한 수치모델개발

  • 왕수균
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.04a
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    • pp.137-140
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    • 2003
  • This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant degraded through cometabolism in dual-porosity soils during the in situ bioaugmentations. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept [Molz et at., 1986〕 were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailablity of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective in situ bioaugmentation scheme.

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Epitaxial growth of in-situ doped polycrystalline 3C-SiC for M/NEMS application (M/NEMS용 in-situ 도핑된 다결정 3C-SiC 박막 성장)

  • Kim, Kang-San;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.18-19
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    • 2008
  • Polycrystalline(poly) 3C-SiC film is a promising structural material for M/NEMS used in harsh environments, bio and fields. In order to realize poly 3C-SiC based M/NEMS devices, the electrical properties of poly 3C-SiC film have to be optimized. The n-type poly 3C-SiC thin film is deposited by APCVD using HMDS$(Si_2(CH_3)_6)$ as single precursor and are in-situ doped using N2. Resistivity values as low as 0.014 $\Omega$cm were achieved. The carrier concentration increased with doping from $3.0819\times10^{17}$ to $2.2994\times10^{19}cm^{-3}$ and electronicmobility increased from 2.433 to 29.299 $cm^2/V{\cdot}s$.

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Microstructural and Mechanical Characteristics of In Situ Synthesized Chromium-Nickel-Graphite Composites

  • Pirso, Juri;Viljus, Mart;Letunovits, Sergei;Juhani, Kristjan
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.631-632
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    • 2006
  • Cr-C-Ni composites were synthesized in situ from elemental powders of Cr, Ni and C by high energy milling followed by reactive sintering. The milled powders with the grain size in nano-scale were pressed to compacts and sintered. During the following thermal treatment at first the chromium carbide was formed and then the $Cr_3C_2-Ni$ cermets were sintered in one cycle. The interface between the binder phase and the carbide grains of the in situ composite has a good bonding strength as it is not contaminated with oxidation films or other detrimental surface reactions.

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Effect of Heterogeneous Microstructure on the Fracture Toughness of Weld Metal (용착금속의 파괴인성에 미치는 불균일 미세조직의 영향)

  • 정현호;김철만;김형식;김우식;홍성호
    • Journal of Welding and Joining
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    • v.17 no.2
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    • pp.36-43
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    • 1999
  • The effect of microstructure on the fracture toughness of multi pass weld metal has been investigated. The micromechanisms of fracture process are identified by in-situ scanning electron microscopy(SEM) fracture observation using single edge notched specimen. The notches of the in-situ fracture specimens were carefully located such that the ends of the notches were in the as-deposited top bead and the reheated weld metal respectively. The observation of in-situ fracture process for as-deposited top bead indicated that as strains are applied, microcracks are formed at the interfaces between soft proeutectoid ferrite and acicular ferrite under relatively low stress intensity factor. Then, the microcracks propagate easily along the proeutectoid ferrite phase, leading to final fracture. These findings suggest that proeutectoid ferrite plays an important role in reducing the toughness of the weld metal. On the other hand, reheated regions showed that the microcrack initiated at the notch tip grows along the localized shear bands under relatively high stress intensity factor, confirming that reheated area showing momogeneous and fine microstructure would be beneficial to the fracture resistance of weld metal.

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Filter Plate Micro Trap as a Device for in situ Cultivation for Environmental Microorganisms (환경시료에 존재하는 미생물 배양을 위한 filter plate micro trap의 개발)

  • Jung, Da-Woon;Ahn, Tae-Seok
    • Journal of Life Science
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    • v.22 no.6
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    • pp.723-729
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    • 2012
  • Filter plate microbial trap (FPMT) was invented as an in situ cultivation device for the isolation of bacteria from natural environments. FPMT consists of a medium and membrane filters (0.45 ${\mu}m$ pore size) and microorganisms and compounds can be moved freely moved into the medium. This device was applied to two soil samples of Greenland. The microbial diversity of both soil samples by FPMT was higher than that by the conventional Petri dish-based method. Moreover, novel bacterial species were isolated by FPMT. The new FPMT is effective for in situ cultivation of natural samples and could be applicable to the isolation of uncultivable microorganism.

Ex-situ Reductive Dechlorination of Carbon Tetrachloride by Iron Sulfide in Batch Reactor

  • Choi, Kyung-Hoon;Lee, Woo-Jin
    • Environmental Engineering Research
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    • v.13 no.4
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    • pp.177-183
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    • 2008
  • Ex-situ reductive dechlorination of carbon tetrachloride (CT) by iron sulfide in a batch reactor was characterized in this study. Reactor scaled-up by 3.5 L was used to investigate the effect of reductant concentration on removal efficiency and process optimization for ex-situ degradation. The experiment was conducted by using both liquid-phase and gas-phase volume at pH 8.5 in anaerobic condition. For 1 mM of initial CT concentration, the removal of the target compound was 98.9% at 6.0 g/L iron sulfide. Process optimization for ex-situ treatment was performed by checking the effect of transition metal and mixing time on synthesizing iron sulfide solution, and by determining of the regeneration time. The effect of Co(II) as transition metal was shown that the reaction rate was slightly improved but the improvement was not that outstanding. The result of determination on the regeneration time indicated that regenerating reductant capacity after $1^{st}$ treatment of target compound was needed. Due to the high removal rates of CT, ex-situ reductive dechlorination in batch reactor can be used for basic treatment for the chlorinated compounds.

Comparison of 2,4,6-tribromophenol removal using in-situ liquid ferrate(VI) and stable ferrate(VI) (원위치 제조 액상 Ferrate(VI)와 안정화 Ferrate(VI)를 이용한 2,4,6-tribromophenol의 제거 비교연구)

  • Laksono, Fajar Budi;Jung, Sun-Young;Kim, Il-Kyu
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.2
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    • pp.123-130
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    • 2018
  • This paper provided the information related to the removal of 2,4,6-tribromophenol using in-situ and stable liquid ferrates(VI). This research's goal was to observe the differences of oxidation power between in-situ liquid ferrate(VI) and stable liquid ferrate(VI). The in-situ liquid ferrate(VI) ($FeO_4{^{2-}}$) has been successfully produced with the concentration 42,000 ppm (Fe) after 11 minutes of reaction time. The stable liquid ferrate(VI) was also successfully produced following the modification method by Sharma with the produced concentrations 7,000 ppm. The stable liquid ferrate(VI) was stable for 44 days and slightly decreased afterwards. This research has been carried out using 2,4,6-tribromophenol as the representative compound. Both of ferrates(VI) have the highest oxidation capability at the neutral condition. Furthermore, the stable liquid ferrate(VI) has higher oxidation power than the in-situ liquid ferrate(VI).

In-situ Synthesis and Investment Casting of Titanium Matrix (TiC+TiB) Hybrid Composites (Ti기 (TiC+TiB) 하이브리드 복합재료 반응생성합성 및 정밀주조)

  • Sung, Si-Young;Park, Keun-Chang;Lee, Sang-Hwa;Kim, Young-Jig
    • Journal of Korea Foundry Society
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    • v.24 no.3
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    • pp.159-164
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    • 2004
  • The aim of the present work is to investigate the possibility of in-situ synthesis and net-shape forming of the titanium matrix (TiC+TiB) hybrid composites using a casting route. From the scanning electron microscopy, electron probe micro-analyzer, X-ray diffraction and thermodynamic calculations, the spherical TiC and needle like TiB reinforced hybrid titanium matrix composites could be obtained in-situ by the conventional melting and casting route between titanium and $B_4C$. No melt-mold reaction occurred between the titanium matrix (TiC+TiB) hybrid composites and the SKK mold, since the mold is consisted with interstitial and substitutional metal-mold reaction products. Not only the sound in-situ synthesis but also the economic net-shape forming of the titanium matrix (TiC+TiB) hybrid composites could be possible by the conventional casting route.