• 한국의류학회지
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• 제36권10호
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• pp.1117-1124
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• 2012

This study was a preliminary study to investigate the influence of surface morphology and characteristics on the self-cleaning of substrates. PI film was treated by $O_2$ plasma to modify the surface; in addition, AFM and Fe-SEM were employed to examine the morphological changes induced on a PI film treated by $O_2$ plasma and surface energies calculated from measured contact angles between several solutions and PI film based on the geometric mean and a Lewis acid base method. The surface roughness of PI film treated by $O_2$ plasma increased with the duration of the $O_2$ plasma on PI film due to the increased surface etching. The contact angle of film treated by $O_2$ plasma decreased with the increased treatment time in water and surfactant solution; in addition, the surface energy increased with the increased treatment times largely attributed to the increased portion on the polar surface energy of PI film. The coefficient of the correlation between surface roughness and surface polarity such as contact angle and surface energy was below 0.35; however, it was over 0.99 for the contact angle and surface energy.

• 약학회지
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• 제38권6호
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• pp.703-711
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• 1994

We synthesized D-1,3-dioxolanyl acetate from D-mannose using Frazer-Reide reaction and D-1,3-oxathiolanyl acetate from either D-mannose or D-galactose in good yields. These acetates were conjugated with various disilylated pyrimidine base using trimethylsilyl trifluoromethane sulfonate as a Lewis acid catalyst to obtain 32 different D-nucleosides.

• Archives of Pharmacal Research
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• 제15권1호
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• pp.87-90
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• 1992

The syntheses of novel heterocyclic base modified pyrimidine nucleosides are described. 5, 6-dimethyl-4-hydroxy-3-methoxy-1-$(\beta$-D-ribofuranosyl)2(1H)-pyridinone 7 was synthesized by condensation of silylated 5, 6-dimethyl4-hydroxy-3-methoxy-2(1H)-pyridione 7 was synthesized by condensation of silylated 5, 6-dimethyl-4-hydroxy-3-methoxy-2(1H)-pyridinone with $\beta$-D-ribofuranose-1-acetate-2, 3, 5-tribenzoate in dichloroethane in the presence of Lewis acid followed by debenzoylation. The 2, 2'-anhydro-5, 6-dimethyl-2-hydroxy-3-methoxy-1-$\beta$-D-arabinofuranosyl-4-pyridinone 8 was obtained from the reaction of the free ribonucleoside 7 and diphenyl carbonate in DMF. None of these compounds showed any significant antiviral ad antitumor activities in vitro tests.

• 한국의류산업학회지
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• 제15권2호
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• pp.302-308
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• 2013

This study is a preliminary investigation of the influence of surface characteristics of substrates on detergency of particulate soil. The surface of PET film was modified with NaOH and NaOH+ethylene diamine on different times. The surface morphology of the film was scanned by AFM and surface energies were calculated from measured contact angles between several solutions and film based on the geometric mean and a Lewis acid base method. The surface morphology of PET film treated with NaOH and NaOH+ethylene diamine became more etched, and the surface area, surface roughness and the coefficient of friction of film increased with treatment of NaOH and NaOH+ethylene diamine. The contact angle of film treated with NaOH and NaOH+ethylene diamine decreased in water and surfactant solution; in addition, the surface energy increased was largely attributed to the increased portion on the polar surface energy of film. However, the effect of the diamine addition to the NaOH treatment solution on surface characteristics of PET film was insignificant.

• 상하수도학회지
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• 제27권1호
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• pp.121-128
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• 2013

The concern for dissolved phosphate in water/wastewater has been increasing because of the risk for eutrophication. A variety of conventional and advanced technologies were applied to meet the enforced new regulation of phosphate around the world. However, there still remained a lot of challenge because most introduced/developed method, for example, biological and physic-chemical treatment is not easy to satisfy the new regulation of phosphate in water. In order to meet the new regulation, the application of ion exchanger has been tried which showed that the removal efficiency for phosphate was strongly determined by in the presence of the competing ion, especially sulfate. As results, a new class of ion exchanger governed by ligand exchange was developed and investigated to increase the selectivity for phosphate. The current study using organic/inorganic anion exchanger developed with Lewis acid-base interaction confirms the selectivity for phosphate over sulfate. According to isotherm test and column test, the value of the maximum phosphate uptake (Q) showed 64 mg/g as $po{_4}^{3-}$ and the breakthrough for phosphate occurs after 1000 min and completely finishes at 2500 min, respectively.

• 산업기술연구
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• 제27권A호
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• pp.203-209
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• 2007

본 연구는 목재로서 활용가치가 적은 수피(bark)를 활용하여 수질오염물질을 제거할 수 있는 여과 시스템에 대한 기초연구로서 소나무의 일종인 loblolly pine(Pinus taeda L.) 수피의 인 ($PO_4-P$) 흡착특성을 연구하였다. 실험에 사용된 수피는 입상형태로서 polyallylamine hydrochloride로 전처리하여 회분식 등온 흡착실험을 수행하였다. 회분식 등온흡착실험은 수용액 pH 3~pH 8범위에서, 인의 농도별(10, 20, 30, 40 mg/L)로 수행하였다. pH 5에서 가장 높은 인 제거 효율을 나타냈으며, 수용액의 pH는 실험 후 pH 3으로 감소하였다. 이러한 감소는 수피에 의한 phosphate의 흡착이 Lewis acid-base 반응으로서 이 과정에서 $H^+$의 방출로 인하여 나타난 현상인 것으로 여겨지며, 주된 반응 메카니즘은 더 연구할 필요성이 있다. 인 흡착은 초기에 빠른 속도로 진행되었으며 대략 200분 이후에 평형에 도달하였고, 시간이 지날수록 흡착양이 증가하는 경향을 보였다. 인의 흡착특성 결과는 Langmuir 등온흡착식과 Freundlich 등온흡착식으로 설명될 수 있으며, 등온흡착식 적용결과, 흡착제에 대한 최대 흡착능은 7.14 mg/g 이며 다른 흡착제와 비교하여 더 높았다. 실험결과와 모델에 의한 흡착능을 비교하고자 pseudo second-order model을 적용하여 흡착 동역학 상수를 구하였다. 또한 EDXA분석으로 회분식 흡착실험 후 수피와 인이 결합되어있는 것을 확인할 수 있었다.

• 대한화장품학회지
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• 제30권3호
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• pp.409-414
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• 2004

코직산은 티로시나제의 억제에 의한 미백효능을 가지는 물질로 널리 알려져 있으나, 낮은 안정성으로 인하여 화장품 원료로의 사용에 제약을 갖고 있다. 이에 본 연구에서는 유기합성적 방법에 의해 안정성과 미백효과를 가지는 코직산 유도체를 고수율로 합성하였다. $O-pentaacetyl-{\beta}-D-glucose를$ 루이스산과 유기염기를 이용하여 위치 선택적이고, 입체 선택적으로 코직산의 6번 위치에 도입시켜 $kojic\;acid\;6-O-2',3',4',6'-tetraacetyl-{\beta}-D-glucopyranoside\;(KTGP, 80{\%})를$ 합성한 후, 가수분해하여 kojic acid 6-0-f-D-glucopyranoside $(KGP, 70\%)를$ 수득하였다. $^1H-NMR과\;^{13}C-NMR$ 분석으로 구조를 확인하였다. KGP를 가지고 티로시나제 활성저해, 프리라디칼소거능과 멜라닌합성저해 실험을 실시하였고, 그 결과 티로시나제 활성저해와 프리라디칼소거능에서 코직산보다 높거나 비슷한 활성을 보여주었다. 코직산 수준의 미백효능을 확인하였기에 유기 화학적으로 합성된 KGP의 미백원료로서 사용을 기대할 수 있다.

• 한국의류학회지
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• 제34권11호
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• pp.1880-1888
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• 2010

This study was a preliminary investigation of the influence of surface characteristics of substrates on the detergency of particulate soil. A PET film was surface modified with NaOH and DMF for different times. The surface morphology of the film was scanned by AFM and the surface energies were calculated from the measured contact angles between several solutions and film based on a geometric mean and the Lewis acid base method. The surface morphology of the PET film treated with NaOH and DMF became more etched and swelled with an increased treatment time, respectively. The surface roughness and surface area of film treated with NaOH enlarged with increased treatment time. However, the coefficient of friction of film treated with NaOH and coefficient of friction, surface roughness, and surface area of film treated with DMF increased and then decreased with increased treatment time. The contact angle of film treated with DMF decreased with increased treatment time in water and surfactant solution; however, the effect of treatment time on the contact angle was different in both solutions for film treated with NaOH. By the treatment of PET film with NaOH and DMF, the polar group of the surface energy increased and the nonpolar group decreased; however, the change of total surface energy was not significant.

• 한국재료학회지
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• 제17권1호
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• pp.31-36
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• 2007

Nanoimprint lithography (NIL) is a new lithographic method that offers a sub-10nm feature size, high throughput, and low cost. One of the most serious problems of NIL is the stiction between mold and resist. The antistiction layer coating is very effective to prevent this stiction and ensure the successful NIL results. In this paper, an antistiction layer was deposited by VSAM (vapor self assembly monolayer) method on silicon samples with FOTS (perfluoroctyltrichlorosilane) as a precursor for making an antistiction layer. A specially designed LPCVD (low pressure chemical vapor deposition) was used for this experiment. All experiments were achieved after removing the humidity. First, the evaporation test of FOTS was performed for checking the evaporation temperature at low pressure. FOTS was evaporated at 5 Tow and $110^{\circ}C$. In order to evaluate the temperature effect on antistiction layer, chamber temperature was changed from 50 to $170^{\circ}C$ with 0.1ml of FOTS for 1 minute. Good hydrophobicity of all samples was shown at about $110^{\circ}$ of contact angle and under $20^{\circ}$ of hysteresis. The surface energies of all samples calculated by Lewis acid/base theory was shown to be about 15mN/m. The deposited thicknesses of all samples measured by ellipsometry were almost 1nm that was similar value of the calculated molecular length. The surface roughness of all samples was not changed after deposition but the friction force showed relatively high values and deviations deposited at under $110^{\circ}$. Also the white circles were founded in LFM images under $110^{\circ}$. High friction forces were guessed based on this irregular deposition. The optimized VSAM process for FOTS was achieved at $170^{\circ}C$, 5 Torr for 1 hour. The hot embossing process with 4 inch Si mold was successfully achieved after VSAM deposition.