• 제목/요약/키워드: Selective adsorption

검색결과 212건 처리시간 0.03초

Growth Inhibition of Microcystis aeruginosa by a Glycolipid-Type Compound from Bacillus subtilis C1

  • Kim, Hee-Sik;Ahn, Chi-Yong;Joung, Seung-Hyun;Ahn, Jong-Seog;Oh, Hee-Mock
    • Journal of Microbiology and Biotechnology
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    • 제20권8호
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    • pp.1240-1242
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    • 2010
  • We attempted to identify the compound responsible for the growth inhibition of Microcystis aeruginosa occurring when a culture broth of Bacillus subtilis C1 was added to the medium. The active compound was purified from B. subtilis C1 culture broth by adsorption chromatography and HPLC, and was identified as a type of glycolipid based on $^1H$ NMR and MS analyses. The purified active compound completely inhibited the growth of M. aeruginosa at a concentration of 10 ${\mu}g/ml$. This is the first report of a glycolipid produced by a Bacillus strain that has potential as an agent for the selective control of bloom-forming M. aeruginosa.

기체 투과 선택성 포장 필름 내 배 호흡현상 예측 (Predicting Respiration Rate of Pear in film package of Selective gas permeation)

  • 심승우;류동완;박찬영
    • 한국산업융합학회 논문집
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    • 제2권1호
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    • pp.105-112
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    • 1999
  • Model predicting the respiration rate of pear under modified LDPE film pouch has been developed. The assumptions of the model have three bases; 1) respiration rate is depending on $CO_2$ and $O_2$ concentration in the package, 2) the oxidation of glucose in pear generates carbon dioxides, and 3) gases permeation through the package film bases on the Langmuir adsorption theory and Fick's law. The simulated results agreed fairly well with the experimental data so as this model to be useful in designing the modified atmospheric packaging system.

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유독성 유기용매의 촉매산화공정에서 혼합조성에 따른 간섭효과 (Inhibition Effects of Toxic Solvent Mixture in Catalytic Oxidation Process)

  • 이승범;김원일;홍인권;김형진
    • 환경위생공학
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    • 제16권3호
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    • pp.72-79
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    • 2001
  • The selective catalytic oxidation of toxic aromatic solvents (benzene, toluene, ethylbenzene, and styrene) and their mixtures were studied on a $Pt/{\;}{\gamma}-Al_2O_3$ catalyst at temperature ranging from $160~350^{\circ}C$. The deep conversion of aromatic solvents was increased as the inlet concentration was decreased and the reaction temperature was increased. The reactivity increases in order benzene > toluene > ethylbenzene > styrene. In mixture, remarkable effects on reaction rate and selectivity have been evidence ; the strongest inhibition effect is shown by styrene and increase in a reverse order with respect to that of reactivity. The inhibition effect was increased in order styrene > ethylbenzene > toluzene > benzene. This trend is due to the competition adsorption between the two or three reactants on the oxidized catalyst. Also, the deep conversion change of benzene was a small in tertiary mixtures(including of benzene and styrene) comparing with conversion characteristics of binary mixture with styrene. This result was due to small concentration of styrene. which had very strong inhibition effect.

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Synthesis and Permeation Characteristics of Zeolite Membranes

  • Kita, Hidetoshi
    • 한국막학회:학술대회논문집
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    • 한국막학회 1997년도 추계 총회 및 학술발표회
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    • pp.5-8
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    • 1997
  • Introduction : Membranes made from inorganic materials are generally superior to organo-polymeric materials in thermal and mechanical stability, and chemical resistance. Among inorganic materials zeolite is a promising candidate for a high performance membrane because of the unique characteristics of zeolite crystals such as molecular sieving, ion exchange, selective adsorption and catalysis. Although there are many recent reportsl on the preparation of zeolitc membranes and the gas permeation through the membranes, only a limited number of publications deal with pervaporation studies. Recently, we have reported a high pervaporation performance of NaA zeolite membrane for the separation of water/organic liquid mixtures. and of NaY zeolite menlbrane for the separation of methanol/MTBE. Here, preparation of zeolite (LTA, ZSM-5 and FAU) membranes and their permeation properties are discussed.

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

  • 김봉수;한승오;박정호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 하계학술대회 논문집 D
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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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Photocurrent of CdSe nanocrystals on singlewalled carbon nanotube-field effect transistor

  • Jeong, Seung-Yol;Lim, Seung-Chu;Lee, Young-Hee
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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    • pp.40-40
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    • 2010
  • CdSe nanocrystals (NCs) have been decorated on singlewalled carbon nanotubes (SWCNTs) by combining a method of chemically modified substrate along with gate-bias control. CdSe/ZnS core/shell quantum dots were negatively charged by adding mercaptoacetic acid (MAA). The silicon oxide substrate was decorated by octadecyltrichlorosilane (OTS) and converted to hydrophobic surface. The negatively charged CdSe NCs were adsorbed on the SWCNT surface by applying the negative gate bias. The selective adsorption of CdSe quantum dots on SWCNTs was confirmed by confocal laser scanning microscope. The measured photocurrent clearly demonstrates that CdSe NCs decorated SWCNT can be used for photodetector and solar cell that are operable over a wide range of wavelengths.

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HCl 용액에서의 중금속 이온, $Cd^{2+}$-$Cl^{3+}$-$Pb^{2+}$의 흡착 특성 (Adsorption Property of Heavy Metal ion, $Cd^{2+}$-$Cl^{3+}$-$Pb^{2+}$+ in HCI Solution)

  • 박원우;이봉헌
    • 한국환경과학회지
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    • 제5권6호
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    • pp.779-783
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    • 1996
  • Cation exchange distribution coefficients of poly(dithiocarbamate) were presented for $Cd^{2+}$, $Cr^{3+}$, and $Pb^{2+}$ in HCI. The distribution coefficients were determined tv using the batch method. Based on these distribution data, the separation possibilities of the heavy metal ions were discussed. The distribution coefficients of three heavy metal ions on dithiocarbamate resin were decreased as HCI concentrations were increased. The selective separation of $Cr^{3+}$ and $Cd^{2+}$ was possible by using 0.1M HCl in dithiocarbamate resin and the reproducibility test showed that the average absorptivity of resin was 90% in the case of $Cd^{2+}$ ion by the column method.

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유기 자기조립 단분자막의 레이저 포토 패터닝을 이용한 금속 박막의 미세 형상 가공 기술 (Micromachining Thin Metal Film Using Laser Photo Patterning Of Organic Self-Assembled Monolayers)

  • 최무진;장원석;신보성;김재구
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.219-222
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    • 2003
  • Self-Assembled Monolayers(SAMs) by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecular and bio molecular. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance in selective etching of thin metal film of Self- Assembled Monolayers. In this report, we present the micromachining thin metal film by Mask-Less laser patterning of alknanethiolate Self-Assembled Monolayers.

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잎담배중 유리 및 Glycoside형태로 존재하는 휘발성 향기성분 (Free and Glycosidically Bound Volatile Components in Tobacco Leaves(Nicotiana tabacum L.))

  • 김영회;나도영;김옥찬;서철원;김용태
    • 한국연초학회지
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    • 제14권1호
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    • pp.79-86
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    • 1992
  • Free and glycosidically bound volatiles from three green tobacco leaves(NC 82, KF 109 and Br-21) were separated by nonionic resin Amberlite XAD-2 adsorption column chromatography and election by selective solvents. Aglycones from the glycosidically bound fractions were released by enzymatic hydrolysis with almond B-glucosidase. A total of 20 components identified from free and glycosidically bound fractions, the major components were benzaldehyde, benzyl alcohol, 2-phenylethyl alcohol, 3-oxo- -ionol, 3-hydroxy-B-ionone, 3-oxo-7, 8-dihydro-n-ionol and scopoletin. Six Cl.B norisoprenoids identified in this study, which have been described to possess a characteristic tobacco aroma-enhancing effect, were not presented in free forms but rather bound glycosidic forms.

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디젤 SCR 후처리장치 내 공간속도가 NOx 저감에 미치는 영향 (Effect of Space Velocity on the DeNOx Performance in Diesel SCR After-Treatment System)

  • 왕태중;백승욱;강대환;길정기;여권구
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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    • pp.49-54
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    • 2006
  • The present study conducted a numerical modeling on the diesel SCR (selective catalytic reduction) system using ammonia as a reductant over vanadium-based catalysts $(V_2O_5-WO_3/TiO_2)$. Transient modeling for ammonia adsorption/desorption on the catalyst surface was firstly carried out, and then the SCR reaction was modeled considering for it. In the current catalytic reaction model, we extended the pure chemical kinetic model based on laboratory-scale powdered-phase catalyst experiments to the chemico-physical one applicable to realistic commercial SCR reactors. To simulate multi-dimensional heat and mass transfer phenomena, the SCR reactor was modeled in two dimensional, axisymmetric domain using porous medium approach. Also, since diesel engines operate in transient mode, the present study employed an unsteady model. In addition, throughout simulations using the developed code, effects of space velocity on the DeNOx performance were investigated.

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