• 제목/요약/키워드: Molecular Surface

검색결과 2,074건 처리시간 0.031초

전주지역에서 다환방향족 탄화수소의 건식 침적 측정 (Measurement of Dry Deposition of Polycyclic Aromatic Hydrocarbons in Jeoniu)

  • 김형섭;김종국;김영성
    • 한국대기환경학회지
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    • 제23권2호
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    • pp.242-249
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    • 2007
  • Deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) were measured at the Chonbuk National University located in Jeonju between June and November 2002. Fluxes of gaseous and particulate PAHs were separately obtained using a water surface sampler (WSS) and a dry deposition plate (DDP). Most of PAHs were deposited in the gaseous form since the low molecular weight PAHs dominates in the atmosphere. The deposition velocity of particulate PAHs was higher than that of gaseous PAHs when the molecular weight was low, but substantially decreased as the fine particle fraction increased with molecular weight. The deposition velocity was generally higher at high wind speeds. However, increase in the deposition velocity in unstable atmospheric conditions was also observed for gaseous PAHs of intermediate molecular weight.

Molecular Imprints in Nanostructured Polymer Surfaces - A New Generation of Biomimetic Materials for Chemical Sensors

  • Haupt, Karsten
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.31-32
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    • 2006
  • We describe the preparation of nanostructured molecularly-imprinted surfaces using nanomolding on porous alumina. In molecular imprinting functional and cross-linking monomers are copolymerized in the presence of a molecular template, resulting in synthetic receptor materials. The drug propranolol and the dye fluorescein were used as the molecular imprinting templates. Binding studies with imprinted and non-imprinted surfaces revealed specific recognition of the templates and thus the existence of selective binding sites. In addition, the surface properties of the films were studied by water contact angle measurements. It was found that, depending on the monomers used, certain nanostructures induced great changes in the wetting properties of the surface.

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Quantitative Structure-Activity Relationships (QSAR) Study on C-7 Substituted Quinolone

  • 이근우;권순영;황선구;이재욱;김호징
    • Bulletin of the Korean Chemical Society
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    • 제17권2호
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    • pp.147-152
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    • 1996
  • To see the quantitative relationship between the structures of the C-7 substituted quinolones and their antibacterial activities, theoretical parameters such as the molecular van der Waals volume, surface area and some electrostatic parameters based on the molecular electrostatic potential, which represent lipophilicity, and some quantum mechanical parameters are introduced as descriptors. The sixteen substituted quinolone derivatives and twenty bacteria are used for the study. It is found that the QSARs of C-7 substituted quinolones are obtained for eleven bacteria and our descriptors are more useful for Gram positive organisms than negative ones. It is also shown that molecular surface area (or molecular Waals volume) of the C-7 substituent and net charge of C-7 atom of the quinolones are the descriptors of utmost importance.

Langmuir-Blodgett 법을 이용한 유기초박막의 제작조건 및 분자배향에 관한 연구 (A Study on the Deposition Condition and Molecular Orientation of the Ultrathin Organic Films using the Langmuir-Blodgett Technique)

  • 김태완;신동명;최강훈;권영수;강도열
    • 대한전기학회논문지
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    • 제43권2호
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    • pp.303-311
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    • 1994
  • Optimum conditions for the deposition of N-docosylquinolium-TCNQ ultrathin organic films using the Langmuir-Blodgett etchnique and the molecular orientation and alignment of the LB films were studied. The $\pi$-A isotherm of the N-docosylquinolium-TCNQ was measured at the air-water interface varying with the subphase temperature, subphase pH, compressing speed and amounts of solutions for spreading. The LB film was deposited under the surface pressure of 30mN.m and 45mN/m and other deposition conditions. The molecular orientation and alignment of the LB films were studied by the polarization absorption technique. The $\pi$-A isotherm showed that the stable N-docosylquinolium -TCNQ monolayer was formed on the water surface at the condition of 25$^{\circ}C$,pH 5.6, molecular density of 2.1${\times}$10S014T~2.6${\times}$10S014T/cmS02T. The LB film was deposited under the surface pressure of 45mN/m had better packing density, orientation and alignment than the film of 30mN/m.

Bacterial Surface Display of $GFP_{UV}$ on Bacillus subtilis Spores

  • Kim, Jung-Hyung;Roh, Chang-Hyun;Lee, Chang-Won;Kyung, Do-Hyun;Choi, Soo-Keun;Jung, Heung-Chae;Pan, Jae-Gu;Kim, Byung-Gee
    • Journal of Microbiology and Biotechnology
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    • 제17권4호
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    • pp.677-680
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    • 2007
  • To analyze a cotG-based Bacillus subtilis spore display system directly, $GFP_{UV}$ was expressed on the surface of Bacillus subtilis spores. When $GFP_{UV}$ was fused to the C-terminal of the cotG structural gene and expressed, the existence of a $CotG-GFP_{UV}$ fusion protein on the B. subtilis spore was confirmed by flow cytometry confocal microscopic analysis. When the cotG anchoring motif was deleted, no fluorescence emission was observed under flow cytometry and confocal microscopic analysis from the purified spore, confirming the essential role of CotG as an anchoring motif. This $GFP_{UV}$ displaying spore might be used for another signaling application triggered by intracellular or extracellular stimuli.

Effects of Metal Anion Complexes in Electrolyte on the Properties of Anodic Oxide Films on ADC12 Al Alloy

  • Yoo, Hyeonseok;Lee, Chulho;Oh, Kiseok;Choi, Jinsub
    • 한국표면공학회지
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    • 제49권2호
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    • pp.130-134
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    • 2016
  • The anodization of ADC12 aluminum alloy was investigated in the metal anionic acid media. Anodic oxide films containing foreign elements were formed on ADC12 Al alloy by anodization in the anion complex solution. Furthermore, the rough surface and cracks were considerably smoothened by the deposit of metal anions. When the size of metal anion was small, relatively large amount of metal anions was loaded in anodic films. Existence of $MoO_3$, $TiO_2$ and MgO was confirmed by XPS. According to the results of Tafel analysis, Mo oxide represented the most noble anti-corrosion potential due to $MoS_2$ formation. Corrosion current densities were generally higher than that of pristine anodic oxide without anion complexes.

Medium Optimization for the Production of Probiotic Lactobacillus acidophilus A12 Using Response Surface Methodology

  • Lee, Na-Kyoung;Park, Yeo-Lang;Choe, Ga-Jin;Chang, Hyo-Ihl;Paik, Hyun-Dong
    • 한국축산식품학회지
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    • 제30권3호
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    • pp.359-364
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    • 2010
  • Lactobacillus acidophilus A12 was isolated from chicken feces for use as an immunostimulating livestock probiotic. The purpose of this study was to optimize the production of L. acidophilus A12 using response surface methodology (RSM). Initially, the influence of growth medium was studied in terms of carbon sources (glucose, fructose, lactose, glycerol, sucrose, ethanol, and mannitol), nitrogen sources (beef extract, yeast extract, malt extract, and tryptone), and inorganic salts ($CaCl_2$, $MgSO_4$, $KH_2PO_4$, $(NH_4)_2SO_4$, $FeSO_4$, and NaCl). Through one factor-at-a time experiment, lactose, yeast extract, and $CaCl_2$ were determined to be the best sources of carbon, nitrogen, and inorganic salt, respectively. The optimum composition was found to be 17.7 g/L lactose, 18.6 g/L yeast extract, and 0.9 g/L $CaCl_2$. Under these conditions, a maximum cell density of 9.33 Log CFU/mL was produced, similar to the predicted value.

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • 제17권12호
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

N-docosylquinolium-TCNQ LB막의 분자배향과 편광특성 (Molecular Orientation and Polarized Absorption Characteristics of N-docosylquinolium-TCNQ LB Film)

  • 최강훈;신동명;한원근;박태곤;강도열
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1992년도 하계학술대회 논문집 B
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    • pp.868-870
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    • 1992
  • Langmuir-Blodgett method is the best candidate for the development of the future molecular electronic devices. But, this molecular thin film devices requires the bulk properties that was influenced by the molecular arrangements and orientations. So, these are of current interest in molecular electronic device fabrications of new materials. In this experiment, the N-docosylquinolium-TCNQ LB films were deposited on the surface pressures of 30 mN/m and 45 mN/m. We measured the polarized UV/visible absorptions of deposited films for the study of the molecular arrangements and orientations. The polarized UV/visible absorption variation on the incidence and polarization angle of the LB film deposited on the surface pressure of 45 mN/m shown methodically variated. So, we concluded that the LB film deposited on 45 mN/mwas arranged better than that obtained at 30 mN/m.

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