• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.175-178
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• 2006

Solid-state dye-sensitized solar cells were fabricated using a polymer matrix in electrolyte in the purpose of the improvement of the durability in the dye-sensitized solar cell. In these dye-sensitized solar cells, the polymer electrolyte consisting of $I_2$, LiI, ionic liquid, ethylene carbonate/propylene carbonate and polymer matrix was casted onto $TiO_2$ electrode impregnated Ruthenium complex dye as a photosensitizer. Photovoltaic properties of solid-state dye-sensitized solar cells using polymer matrix (PMMA, PEG, or PAN) were investigated. Comparing photovoltaic effects of cells using hole conducting polymers (BE or 6P) instead of polymer matrix, we investigated the availability of the solid-state polymer electrolyte in dye-sensitized solar cells.

• Membrane and Water Treatment
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• 제9권2호
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• pp.79-85
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• 2018

In this work, batch adsorption of anionic dye acid green-25 (AG-25) from aqueous solution has been carried out at room temperature using anion exchange membrane (DF-120B) as a noval adsorbent. The effect of various experimental parameters such as contact time, membrane dosage, ionic strength and temperature on the adsorption of dye were investigated. Kinetic models namely pseudo-first-order, pseudo-second-order, Elovich, liquid film diffusion, Bangham and modified freundlich models were employed to evaluate the experimental data. Parameters like adsorption capacities, rate constant and related correlation coefficients for every model are calculated and discussed. It showed that adsorption of AG-25 onto DF-120B followed pseudo-first-order rate expression. Thermodynamic study indicates that adsorption of AG-25 onto DF-120B is an exothermic and spontaneous process.

• 약학회지
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• 제38권5호
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• pp.488-495
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• 1994

To evaluate the feasibility of transmucosal delivery of leucine enkephalin (Leu-Enk) and its synthetic analog, $[D-Ala^2]$-leucine enkephalinamide (YAGFL), their physicochemical stabilities in aqueous buffered solutions were first investigated using a stability indicating high performance liquid chromatography. The degradation of Leu-Enk and YAGFL followed the pseudo-first-order kinetics. From the pH-rate profiles, it was found that the maximal stability of the two pentapeptides was at the pH of about 5.0. The shelf lives $(t_{90%})$ for the degradation of Leu-Enk and YAGFL at pH 5.0 and $40^{\circ}C$ were found to be 48.13 and 50.9 days, respectively. From the temperature dependence of the degradation, activation energies for Leu-Enk and YAGFL were calculated to be 13.61 and 13.47 kcal/mole, respectively. A higher ionic strength and a higher initial peptide concentration in buffered solution slowed the degradation of the two pentapeptides. The addition of 2-hydroxypropyl-${\beta}$-cyclodextrin into the peptide solution did not affect the stability significantly.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1597-1605
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• 2022

A porous silica-based adsorbent was prepared by impregnating the pores of a silica support with the extractant 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) and an additive agent 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C₂mim ⁺ NTf^-₂) as the materials to remove cesium(I) (Cs⁺) ions from seawater. The as-prepared adsorbent showed excellent adsorption performance toward Cs⁺ ions, with adsorption equilibrium reached within 2 h and an adsorption amount of 0.196 mmol/g observed. The solution pH, temperature, and the presence of coexisting metal ions were found to have almost no effect on Cs⁺ adsorption. The adsorption mechanism was considered to proceed via ion exchange between Cs⁺ and C₂mim⁺. In addition, the particle-induced X-ray emission analysis results further clarified that the adsorbed Cs⁺ ion species on the adsorbent was in the form of both CsCl and CsBr.

• Membrane and Water Treatment
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• 제13권2호
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• pp.63-72
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• 2022

Choline chloride-glycerol (1:2 mol), a natural deep eutectic solvent (NADES) is examined as a draw solution in forward osmosis (FO) for dewatering application. The NADES is easy to prepare, low in toxicity and environmentally benign. A polyamide thin film composite membrane was used. Characterization of the membrane confirmed porous membrane structure with good hydrophilicity and a low structural parameter (722 ㎛) suitable for FO application. A dilute solution of 20% (v/v) NADES was enough to generate moderate water flux (14.98 L m^-2h^-1) with relatively low reverse solute flux (0.125 g m^-2h^-1) with deionized water feed. Application in dewatering industrial wastewater feed showed reasonably good water flux (11.9 L m^-2h^-1) which could be maintained by controlling the external concentration polarization and fouling/scaling mitigation via simple periodic deionized water wash. In another application, clarified sugarcane juice could be successfully concentrated. Recovery of the draw solute was accomplished easily by chilling utilizing thermo responsive phase transition property of NADES. This study established that low concentration NADES can be a viable alternative as a draw solute for dewatering of wastewater and other heat sensitive applications along with a simple recovery process.

• 한국식품영양과학회지
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• 제33권3호
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• pp.593-597
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• 2004

천연의 수용성 칼슘자원을 얻기 위하여 현미식초(Br),감식초(Pe) 및 사과식초(Ap)와 다슬기 회분으로 제조한 액상 및 고상의 초산칼슘(LCA및 SCA) 즉, 액상으로 Br-LCA, Pe-LCA, Ap-LCA와 고상으로 Br-SCA, Pe-SCA, Ap-SCA의 품질특성을 조사하였다. 초산칼슘 제조용 식초의 pH는 2.34∼3.06 범위였으며, 식초 100 mL과 반응하는 다슬기 회분의 양은 20.43∼23.50g, 고상 초산칼슘의 수율은 11.02∼13.01%(w/v)이었다. Ap-LCA 및 Ap-SCA의 색상은 연한 황색을 띠었으나 Br-LCA 및 Br-SCA는 갈색, Ap-LCA 및 Ap-SCA는 진한 갈색을 띠었다. Br-LCA, Pe-LCA 및 Ap-LCA의 칼슘함량은 각각 3.02, 2.06 및 2.30%(w/v)이었으며, Br-SCA, Pe-SCA 및 Ap-SCA의 칼슘함량은 각각 27.15, 16.31 및 19.48%(w/w)이었다. 고상초산칼슘의 용해도는 증류수에서 36.82∼39.92%(w/v), 소주에서 32.05∼39.04%(w/v), 진간장에서 13.12∼18.65%(w/v), 이온음료에서 38.35∼38.90%(w/v), 요구르트에서 33.47∼35.58%(w/v)이었으며 두유와 우유에서는 curd를 생성하였다. 신맛과 쓴맛은 표준품에 비하여 낮았으나 떫은 맛, 비린 맛 및 맛난 맛은 높았다.

• Toxicological Research
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• 제31권3호
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• pp.255-264
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• 2015

Heterocyclic amines (HCAs) and acrylamide are unintended hazardous substances generated by heating or processing of foods and are known as carcinogenic and mutagenic agents by the animal experiments. A simple method was established for a rapid and accurate determination of 12 types of HCAs (IQ, MeIQ, Glu-P-1, Glu-P-2, MeIQx, Trp-P-1, Trp-P-2, PhIP, $A{\alpha}C$, $MeA{\alpha}C$, Harman and Norharman) and acrylamide in three food matrices (non-fat liquid, non-fat solid and fat solid) by isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). In every sample, a mixture of internal standards including $IQ-d_3$, $MeIQx-d_3$, $PhIP-d_3$, $Trp-P-2-^{13}C_2-^{15}N$ and $MeA{\alpha}C-d_3$ was spiked for quantification of HCAs and $^{13}C_3$-acrylamide was also spiked for the analysis of acrylamide. HCAs and acrylamide in sample were extracted with acetonitrile and water, respectively, and then two solid-phase extraction cartridges, ChemElut: HLB for HCAs and Accucat: HLB for acrylamide, were used for efficiently removing interferences such as pigment, lipid, polar, nonpolar and ionic compounds. Established method was validated in terms of recovery, accuracy, precision, limit of detection, limit of quantitation, and linearity. This method showed good precision (RSD < 20%), accuracy (71.8~119.1%) and recovery (66.0~118.9%). The detection limits were < 3.1 ng/g for all analytes. The correlation coefficients for all the HCAs and acrylamide were > 0.995, showing excellent linearity. These methods for the detection of HCAs and acrylamide by LC-MS/MS were applied to real samples and were successfully used for quantitative monitoring in the total diet study and this can be applied to risk assessment in various food matrices.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.702-707
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• 2012

지난 수십 년간 다양한 산업에서 사용된 유독 화학물질은 심각한 환경오염을 초래했다. 그리고 이산화탄소나 메탄가스 같은 부산물로 인해 지구 온난화를 가속화 시켰다. 그래서 현재 사용하고 있는 유기 용매를 대체할 새로운 환경친화적인 소재 개발의 중요성이 부각되고 있다. 이온성 액체는 비휘발성, 비가연성, 화학적 불활성과 같은 친환경적인 물성을 지니고 있다. 이 밖에도 넓은 전기화학적 범위, 높은 전기전도도, 넓은 열적 작용 범위 그리고 유기용매와의 높은 용해성과 같은 물성을 지니고 있어 합성용매, 촉매제, 가스추출제로서 각광받고 있는 물질이다. 이번 연구에서는 모폴린 계열의 이온성 액체인 N-ethyl-N-methylmorpholine Bromide, N-butyl-N-methylmorpholine Bromide, N-octyl-N-methylmorpholine Bromide, N-ethyl-N-methylmorpholine Tetrafluoroborate, N-butyl-N-methylmorpholine Tetrafluoroborate, N-octyl-N-methylmorpholine Tetrafluoroborate, N-ethyl-N-methylmorpholine Hexafluorophosphate, N-butyl-N-methylmorpholine Hexafluorophosphate, N-octyl-N-methylmorpholine Hexafluorophosphate를 합성하였다. 합성물의 녹는점, 분해 온도, 전기화학적 안전성은 각각 DSC, TGA, CV로 측정하였다. 할로겐 음이온($Br^-$)을 지닌 이온성 액체는 대체로 높은 온도($150{\sim}200^{\circ}C$)에서 녹는점 갖고, 비교적 낮은 열분해 온도($200{\sim}230^{\circ}C$), 좁은 전기화학적 안전성(3.4~3.6 V)을 보였다. 반면에 무기 음이온($BF_4^-$, $PF_6^-$)을 지닌 이온성 액체들은 비교적 낮은 온도($50{\sim}110^{\circ}C$)에서 녹는점을 가졌고, 높은 열분해 온도($250{\sim}380^{\circ}C$), 넓은 영역에 걸친 전기화학적 안전성(6.1~6.3 V)을 보였다. 뿐만 아니라 동일한 음이온에서도 양이온의 탄소 사슬의 길이에 따라 물성이 상이함을 확인할 수 있었다. 이번 연구를 통해 얻은 자료들은 이온성 액체의 상용화에 밑거름이 될 것이다.

• 한국재난정보학회 논문집
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• 제8권1호
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• pp.18-26
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• 2012

최근 건축구조물에 있어서 초고층화, 대형화의 요구에 의해 고강도 및 고성능 콘크리트의 사용이 증가하고 있다. 하지만 고강도 및 고성능 콘크리트는 화재 시 발생하는 폭렬현상에 취약한 문제가 있다. 폭렬은 화재 시 콘크리트 피복의 손실을 초래하여 내부콘크리트와 철근의 열전달률을 높여 콘크리트와 철근의 온도를 상승시키는 작용을 한다. 이러한 고강도 콘크리트의 화재 시 폭렬을 방지하기 위하여 많은 연구들이 진행되고 있으며, 대표적으로 폴리프로필렌(polypropylene)섬유, 강섬유를 콘크리트에 혼입한 연구들에 의해 폭렬제어성능이 입증되었으나, 섬유 혼입에 따른 유동성 저하 및 시공성 불량 등의 문제점이 제기되고 있다. 따라서 본 연구에서는 이와 같은 문제를 해결하기 위하여 에스테르계 윤활제 및 비이온성 계면활성제를 포함한 코팅액으로 코팅된 Polyamide 섬유를 콘크리트에 혼입하여 내화성능 및 시공성을 확보하였으며, 강도영역별 적정 조건을 실험을 통하여 도출하였다. 그 결과, 13mm의 polyamide 섬유 적용시 강도영역별로 60MPa에서는 $0.8kg/m^3$, 80MPa에서는 $1.0kg/m^3$, 100MPa는 $1.5kg/m^3$이상 혼입시 폭렬 제어 및 시공성 확보가 가능할 것으로 사료된다.

• Journal of Nutrition and Health
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• 제34권1호
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• pp.30-38
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• 2001

This research was conduced to 1) examine the influence of milk group intake on the dietary, considering dietary diversity and nutrient adequacy, 2) identify which foods truly contribute to the intake of specific nutrients 3) point out the dietary problems of this age group. The subjects were 664(male 357, female 307) healthy toddlers of the ages of 12-36 months, who had neither been taking any medicine-type supplements nor had any diseases that affect the dietary intakes, chosen among the outpatients of university and private hospitals in Seoul and Kyonggi province during Mach-August, 1999. The 24 hour recall method and CAN Pro(food analysis program) were used to analyze the amount of nutrient intake. The grouping of the subjects for the analysis by monthly age was based on the 98 Korean Child growth standard. The results that the milk group intake showed significant negative correlations with the grain group(r=-0.194, p<0.01), the vegetable group(r=-0.115, p<0.01) and the fruit group(r=-0.125, p<0.01). It also showed that the more the milk group intake, the lower the Dietary Diversity Score(r=-0.131, p<0.01), and the more the intake of raw milk, the more dificient the intake of iron(r=-0.211, p<0.01), vitamin A(r=-0.169,p<0.01), vitamin B$_1$(r=-0.078, p<0.05) and vitamin C(r=-0.187, p<0.01). Foods contributory to nutrient intake for of 12-14 months of were mostly infant formula, and the contribution ratio was high. In the age of 15-17 months, the subjects obtained most of the nutrients from raw milk., liquid-type yoghurt, soybean milk, cooked rice, etc. As for iron intake, the age of 21-23 month obtained the most from ionic drinks, and 24-29 months from raw milk, chocolate cakes, ionic drinks, etc. Though the NAR(Nutrient Adequacy Ratio) and MAR(Mean Adequacy Ratio) generally tended to increase accordingly with the DDs, as for nutrients Ca, vitamin A, vitamin B$_1$, and vitamin C the NAR marked the highest when the DDS marked the lowest(due to infant formula). And for iron, even when the DDS was 5 the NAR value was low. Im conclusion, the more the milk group intake, the lower was the dietary diversity. High dependency on infant formula and others from milk group over the age of 12 months proved to result in a decrease of nutritious solid food intake, iron deficiency and a low dietary diversity score, which can lead to an unbalanced diet. Therefore, nutrition education towards mothers/caretakers of toddler is of urgent need, in order to reduce the fluid milk group intake of low nutritional density and to provide various solid foods the children. (Korean J Nutrition 34(1):30-38, 2001)