• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3579-3582
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• 2010

We studied the reaction of tri-methylaluminum (TMA) on hydroxyl (OH)-terminated Si (001) surfaces for the initial growth of aluminum oxide thin-films using density functional theory. TMA was adsorbed on the oxygen atom of OH due to the oxygen atom’s lone pair electrons. The adsorbed TMA reacted with the hydrogen atom of OH to produce a di-methylaluminum group (DMA) and methane with an energy barrier of 0.50 eV. Low energy barriers in the range of 0 - 0.11 eV were required for DMA migration to the inter-dimer, intra-dimer, and inter-row sites on the surface. A unimethylaluminum group (UMA) was generated at each site with low energy barriers in the range of 0.21 - 0.25 eV. Among the three sites, the inter-dimer site was the most probable for UMA formation.

• KSBB Journal
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• 제17권4호
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• pp.350-356
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• 2002

다양한 식품의 미생물에 의한 변패를 억제하고 저장성을 높일수 있는 포장필름을 개발하기 위하여, 미생물이 생산하는 천연 항균성 물질을 흡착시킨 silica에 항균제로서 benzoic acid 및 일본산 항균성 필름 첨가제인 JP를 공동 첨가하여 항균성 LDPE 필름을 제조하였다. 천연 항균제로는 methanol 자화 방선균 MO-16과 MO-17이 생산한 항균제를 사용하였으며, 이 물질은 121$^{\circ}C$에서 5분간 열처리시에도 항균력이 유지되는 내열성이 확인되었다. 제조한 silica LDPE 필름의 미생물생육 억제효과를 검토한 결과 조분쇄한 돈육의 경우 포장하여 실온 및 4$^{\circ}C$에서 보존시 시판필름에 비해 미생물생육억제효과가 우수하였다. 고체배지에 제조필름을 첨가하여 E. coli 에 대한 항균효과를 검토한 결과 첨가량에 따라 항균효과가 우수한 것이 입증되었다. 제조필름으로 포장한 4종류의 식품에 대한 저장성을 검토한 결과 시판필름에 비해 저장성이 우수한 것이 확인되었으며 특히 양송이 및 토마토에 대한저장효과가 우수하였다.

• 폴리머
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• 제27권5호
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• pp.397-404
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• 2003

조직공학적 지지체에서의 골수유래 간엽줄기세포의 점착과 성장에 있어서 세포 점착성 단백질과 폴리펩타이드와의 상호작용을 조사하였다. 세포 점착성 물질로 알려진 단백질이나 폴리펩타이드는 락타이드-글리콜라이드 공중합체인 PLGA 필름과 지지체에 흡착하여 코팅되었으며, 이에 골수유래 간엽줄기 세포의 점착과 성장 거동을 비교하였다. 이들 단백질과 폴리펩타이드는 콜라겐 IV형과 피브리노겐, 라미닌, 젤라틴, 피브로넥틴, 폴리(L-라이신)이 사용되었다. 이중 폴리(L-라이신)을 제외한 단백질과 폴리펩타이드는 PLGA 필름 표면에 거의 단층으로 덮어져 흡착되었으며, PLGA 필름과 지지체에서 골수유래 간엽줄기세포가 1일과 2일, 4일간 배양되었다. 세포의 점착과 성장 거동은 sulforhodamine B법으로 평가하였다. PLGA 필름과 지지체에 단백질이나 폴리펩타이드가 흡착되지 않은 표면보다는 흡착된 표면에서의 세포의 점착과 성장이 우수하였다.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1470-1474
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• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.223.2-223.2
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• 2015

Polyurethane acrylate (PUA) has been introduced to utilize as a mold material for sub-100 nm lithography as it provides advantages of stiffness for nanostructure formation, short curing time, flexibility for large area replication and transparency for relevant biomedical applications. Due to the ability to fabricate nanostructures on PUA, there have been many efforts to mimic extracellular matrix (ECM) using PUA especially in a field of tissue engineering. It has been demonstrated that PUA is useful for investigating the nanoscale-topographical effects on cell behavior in vitro such as cell attachment, spreading on a substrate, proliferation, and stem cell fate with various types of nanostructures. In this study, we have conducted surface modification of PUA films with micro/nanostructures on their surfaces using plasma treatment. In general, it is widely known that the plasma treated surface increases cell attachment as well as adsorption of ECM materials such as fibronectin, collagen and gelatin. Effect of plasma treatment on PUA especially with surface of micro/nanostructures needs to be understood further for its biomedical applications. We have evaluated the modified PUA film as a culture platform using adipose derived stem cells. Then, the behavior of stem cells and the level of adsorbed protein have been analyzed.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.961-968
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• 2009

In this work, transparent conductive oxide(TCO) films such as $In_2O_3-SnO_2$(ITO) and $In_2O_3-ZnO$(IZO) were prepared on polyethylene naphthalene(PEN) and glass substrates by using rf-magnetron sputtering system. The TCO films deposited on PEN substrate show very poor conductivity as compared to that of the TCO films deposited on glass substrates. From the results of the residual gas analysis(RGA) test, this poor stability of plastic substrate is presumed to be caused by the deteriorated adhesion between the TCO films and the plastic substrate due to outgassing from the plastic substrate during deposition of TCO films. From our experiment, it is found that the vaporization of some defects in the plastic substrates deteriorate the adhesion of the TCO films to the plastic substrate, because the most plastic substrates containing the water vapor and/or other adsorbed particles such as organic solvents. Mixing of these gases vaporized in the sputtering process will also affect the electrical property of the deposited TCO films. Inorganic thin composite $(SiO_2)_{40}(ZnO)_{60}$ film as a gas barrier layer is coated on the PEN substrate to protecting the diffusion of vapors from the substrate, so that the TCO films with an improved quality can be obtained.

• Journal of Electrochemical Science and Technology
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• 제7권4호
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• pp.277-285
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• 2016

There is a growing demand for simple, cost-effective, and accurate analytical tools to determine the concentrations of biological and environmental compounds. In this study, a stable electroactive thin film of cobalt hexacyanoferrate (Cohcf) was prepared as an in situ chemical precipitant using electrostatic adsorption of $Co^{2+}$ on a silicate sol-gel matrix (SSG)-modified indium tin oxide electrode pre-adsorbed with $[Fe(CN)_6]^{3-}$ ions. The modified electrode was characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical techniques. Electrocatalytic oxidation of hydrazine on the modified electrode was studied. An electrochemical sensor for hydrazine was constructed on the SSG-Cohcf-modified electrode. The oxidation peak currents showed a linear relationship with the hydrazine concentration. This study provides insight into the in situ growth and stability behavior of Cohcf nanostructures and has implications for the design and development of advanced electrode materials for fuel cells and sensor applications.

• The Korean Journal of Ceramics
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• 제3권1호
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• pp.57-61
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• 1997

The effects of pH of solution on structural, electrical, and optical properties of CdS thin films prepared by solution growth method were investigated. With increasing pH of the solution, both crystallinity and transmittance of CdS thin film were deteriorated due to impurities and CdS particles, which were produced by homogeneous nucleation and adsorbed on the surface of CdS thin films. The films were strongly adherent to substrates and has low resistivity of 10~$10^2{\omega}cm$ regrardless of deposition conditions. After annealing at 30$0^{\circ}C$ in Ar atmosphere, the resistivity decreased due to desorption of impurity ions as well as the formation of S vacancies, but after annealing above 35$0^{\circ}C$ it increased by an agglomeration of S vacancies. After annealing in air atmosphere, the film resistivity increased because of the formation of oxide particle in grain boundaries.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.189-194
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• 1999

The antiwear performance of several organic phosphates ,such as tricrecylphosphate(TCP), tributylphosphate(TBP), diphenylhydrogenphosphate(DPHP) ,dissolved in polyol ester based oils is studied. These organic phosphates are well known for antiwear additive for lubricating oil that produce reacted surface protective film. These antiwear additives can drastically reduce wear with their concentration increasing, because the amount of additive adsorbed on metal sur(ace increases. But in the higher concentration region, the wear is increased by excessive and corrosive reaction of the metal surface with these additives. That is to say, there is an optimum concentration for minimum wear. The optimum concentration was different with the kinds of base oils and additives. Different polyolesters showed different optimum concentrations of the additive. The order of optimum concentration among the polyolesters was different with different phosphates. The order of the optimum concentration is shown that the effect of the concentration of additives on the antiwear performance. It can be explained by the interaction between additives and base oils using the solubility parameter.

• 대한화장품학회지
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• 제23권3호
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• pp.152-160
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• 1997

It has been used that fluorinated compounds could be applied to Make-up products. It is that fluorinated compounds are hydrophobicity, lipophobicity and homophobicity. These fluorinated compounds are reported to form a highly protective and effective film against most aggressive chemical and physical agents. In this study we maed a success to formulate the new type of lipstic using perfluoropolymethylisopropylether with low molecular weight which is long wearing and comfortable to use. This PPIE was adsorbed more than 90% in this experiment and formed the well-balanced gel networks even if the selected PPIE is 100% volatile at room temperature. On the basis of the adsorption of PPIE, we developed the new type lipstick, which was highly-lip feeling and had long wearing and non coloration. And these characteristics were verified by actual consumer test.