• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1521-1525
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• 2009

Thermosensitive block copolymers of ethylene oxide and N-isopropylacrylamide (NIPAM) were synthesized. A five armed star shape oligo(ethylene oxide) initiator with a cyclotriphosphazene core was prepared and used for the atom transfer radical polymerization (ATRP) of NIPAM. The lower critical solution temperatures (LCSTs) of the copolymers were 36 to 46 ${^{\circ}C}$, higher than that of PNIPAM (32 ${^{\circ}C}$), depending on their molecular weights. The copolymers were soluble in water below the LCSTs but formed micelles above the LCSTs. The thermosensitive micellization behaviors of the polymers were investigated by fluorescence spectroscopy. With increasing the temperature of an aqueous solution of P2 and pyrene above the LCST, the peak of 333 nm red-shifted to appear around 339 nm and its intensity increased significantly, indicating the micelle formation. The transfer of pyrene into the micelles was also confirmed by a confocal laser scanning microscope. The fluorescence image obtained from P2 in an aqueous pyrene solution exhibited a green emission resulting from the pyrene transferred into the micelles. Salt effects on the solubility of the copolymers in an aqueous solution were investigated. The LCST of P2 decreased sharply as the concentration of sodium chloride increased, while decreased slowly with potassium chloride.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.537-540
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• 2006

Over the past few decades, a considerable number of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in modeling of ionic flows. However, the majority of these researches have not dealt with the chloride binding isotherm based on the mechanism, although chloride binding capacity can significantly impact on the total service life of concrete under marine environment. The purpose of this study is to develop the model of chloride binding isotherm based on the individual mechanism. It is well known that chlorides ions in concrete can be present; free chlorides dissolved in the pore solution, chemical bound chlorides reacted with the hydration compounds of cement, and physical bound attracted to the surface of C-S-H grains. First, sub-model for water soluble chloride content is suggested as a function of pore solution and degree of saturation. Second, chemical model is suggested separately to estimate the response of binding capacity due to C-S-H and Friedel's salt. Finally, physical bound chloride content is estimated to consider a surface area of C-S-H nano-grains and the distance limited by the Van der Waals force. The new model of chloride binding isotherm suggested in this study is based on their intrinsic binding mechanisms and hydration reaction of concrete. Accordingly, it is possible to characterize chloride binding isotherm at the arbitrary stage of hydration time and arbitrary location from the surface of concrete. Comparative study with experimental data of published literature is accomplished to validity this model.

• 한국환경과학회지
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• 제29권5호
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• pp.495-506
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• 2020

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

• Macromolecular Research
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• 제16권2호
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• pp.169-177
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• 2008

This paper reports a facile synthesis of new water-soluble poly(ethylene oxide) (PEO)-based amphiphilic block copolymers showing pH sensitive phase transition behaviors. The copolymers were prepared by atom transfer radical polymerization (ATRP) of methacrylamide type of monomers carrying a sulfonamide group using a PEO-based macroinitiator and a Cu(I)Br/$Me_6TREN$ catalytic system in aqueous media. The resulting polymers were characterized by a combination of $^1H$-NMR, size exclusion chromatography, and UV/Visible spectrophotometeric analysis. The micellization of the block copolymers as a drug-loading mechanism in aqueous media using fluorescein salt was examined as a function of pH. The stable micelle formation and its loading efficacy suggest that the block copolymers can be used as precursors for drug-nanocontainers.

• Bulletin of the Korean Chemical Society
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• 제9권5호
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• pp.317-322
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• 1988

Premicellar precipitation, resolubilization and luminescing behaviors of $RuL_3^{2+}$ (L = bpy, phen, $Me_2bpy$) in aqueous alkylsulfate and sulfonate solutions were studied. Addition of the anionic surfactants to $RuL_3\;^{2+}$ solutions caused initial precipitation which was redissolved by further addition of the surfactants. The apparent solubility products $K_{sp}$'s of the precipitates were evaluated assuming 1:2 salt formation. The values were smaller as the ligand is more hydrophobic and the length of hydrocarbon chain of the surfactant is longer. The $K_{sp}$ values for L = bpy were constant over wide surfactant concentration range. However, those for L = $Me_2bpy$ and also for phen, but to less extent, increased with the surfactant concentration. The resolubilization of 1:2 salts was followed by red-shift of emission band and extensive emission quenching above critical concentration of the surfactants. The critical concentration was lower for more hydrophobic surfactant. For L = $Me_2bpy$, the blue-shifted emission band with enhanced emission intensity was observed in intermediate surfactant concentration region. The high ionic strength of media prevented the precipitate formation, but facilitated the red-shift of the emission bands. The results support that the precipitate is dissolved by accretion of surfactant anions to the salts to form water-soluble surfactant-rich $RuL_3$-surfactant anionic species. These species appeared to aggregate cooperatively to produce large clusters which exhibited the red-shifted emission.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.100.2-101
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• 2003

To satisfy the increasing medical demanding especially for sever burn patients to regenerate full thickness wound cure, this study developed dermis with gelatin based scaffold and perform the biocompatibility tests. To prepare scaffold 30% of gelatin was mixed with sieved salt and dried in the mold to shape then, cross linked with a water-soluble cross-linker, EDAC. Preparing the cell for seeding from a rabbit skin, the fibroblast and keratinocyte were successfully isolated and cultured in vitro. After cell and scaffold were ready, the fibroblast was seeded to the scaffold (∼10$\^$6/ cell/cm ) for preparing dermis and keratinocyte was cultured until forming the sheet. (omitted)

• 보존과학회지
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• 제26권2호
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• pp.133-142
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• 2010

태안 마도 출토 도자기를 대상으로 도자기 탈염에 일반적으로 사용되는 물 세척법에 추가조건(탈염수 양, 교반 및 온도)을 적용하여 탈염효율을 비교 연구하였다. 탈염수 양에 따른 효율실험결과 질량비 20배가 질량비 10배보다 효율은 높았지만, 그 정도가 2배에 미치지 못하여 경제적 측면에서 질량비 10배가 보다 효율적이었다. 또한 탈염처리 중 교반 및 가온에 따라 20~30%의 효율증대는 확인되었지만, 추가기법적용을 위한 에너지사용과 물리화학적 충격에 의한 유물손상의 위해성을 종합적으로 고려한다면 교반 및 가온에 따른 효율증대는 크지 않은 것으로 판단된다.

• 한국수산과학회지
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• 제6권3_4호
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• pp.101-111
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• 1973

생 전복을 액체질소동결, 송풍동결, 반송풍동결, 정지공기동결의 네가지 동결방법으로 동결하여 $-20^{\circ}C$에서 3개월간 저장하여 동결방법에 의한 전복근육의 물성적 변화, 단백질의 변성 등을 검토하여 다음과 같은 결과를 얻었다. 1) 생전복의 사후경직은 다른 어류보다 빨랐다. 2) 압측시험치, 전단시험치는 액체질소동결을 제외하고는 동결방법에 의한 차는 없었고, 저장기간이 길어짐에 따라 약간 감소하였다. 3) 염가용성질소는 동결저장기간중 용출량이 완만하게 감소하였다. 4) 유리수의 유출량은 패주와 다리 사이에는 차가 있었고, 저장기간중 패주는 유리수가 증가하는 경향이었다. 5) Texture의 Panel test 결과 저장기간을 통하여 Texture가 감소하는 경향이었으며, Texture의 변화는 유리수의 변화(P<0.01), 단백질의 변성(P<0.05), 압축시험치의 변화(P<0.05)와 유의의 상관관계가 있었다. 본 논문을 지도하여 주신 동경수산대학 교수 전중 화부 박사 그리고 논문의 작성에 조언해 주신 부산 수산대학 식품공학과 이응호 박사님께 감사의 뜻을 표한다.

• 한국토양비료학회지
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• 제8권2호
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• pp.53-60
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• 1975

소채(蔬채)의 연작(連作)과 다비(多肥)에 의(依)하여 염류(鹽類)가 과잉집적(過剩集積)된 비닐하우스 내(內) 토양(土壤)에 대(對)하여 관수량(灌水量)과 관수회수(灌水回數)에 따른 제염효과(除鹽效果)와 제염(除鹽)이 토마토 수량(收量)에 미치는 영향(影響)을 조사(調査)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 관수량(灌水量)이 증가(增加)할수록 또 1회(回)에 전량(全量)을 관수(灌水)하는 것 보다 2~3회에 나누어서 관수(灌水)하는 것의 제염률(除鹽率)이 높았다. 동일량(同一量)의 관수량(灌水量)에 대(對)한 제염효율(除鹽效率)은 사양토(砂壤士)보다 식양토(埴壤士)에서 높았으며, 150mm 관수시(灌水時) 토양(土壤)의 깊이 30cm 까지의 제염율(除鹽率)은 미사질식양토(微砂質埴壤土)에서 50%, 사양토(砂壤土)에서 34% 이었다. 2. 관수(灌水)에 의(依)한 제염(除鹽)으로 토마토의 수량(收量)은 증가(增加)하였으나, 제염율(除鹽率)과는 반드시 일치(一致)하지는 않았다. 100mm(50-50), 150mm(50-50-50, 혹(或)은 100-50) 및 200mm(100-100) 관수(灌水)한 구(區)의 증가(增收)가 인정(認定)되었다. 3 토마토의 수량(收量)(${\hat{Y}}$)와 표토(表土)의 전기전도도(電氣傳導度)(1 : 5)와는 다음과 같은 관계(關係)가 인정(認定)되었다. 사양토(砂壤士);${\hat{Y}}=1,737.0+437.5X-290.5X^2$ $(R=0.632^{**})$ 미사질식양토(微砂質埴壤士);${\hat{Y}}=1,542.3+454.1X-275.0X^2$ $(R=0.622^{**})$ 4. 수량(收量)과 토양(土壤)의 침출성(浸出性) 양(陽)ion중(中) calcium, magnesium의 함량(含量)과는 상관(相關)이 인정(認定)되지 않았으나, sodium, potassium sodium 함량(含量) 및 sodium과 calcium과의 비(比) (Na/Ca)과 부상관(負相關)이 인정(認定)되었다.

• 생물환경조절학회지
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• 제16권4호
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• pp.328-332
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• 2007

본 연구는 토양 염도(EC)에 따른 토마토의 생육효과를 검토코자 토양 중 염류농도(EC)를 각각 1.0, 2.5, 5.0 및 $7.5dS{\cdot}m^{-1}$로 두어 폿트 실험을 수행하였다. 토마토의 초장, 생체중, 건물중 등 생육은 토양 중 염류농도가 높을수록 억제되었으며 특히 EC $5.0dS{\cdot}m^{-1}$ 이상의 염류농도에서 큰 차이를 나타내었다. 지상부의 생체중과 건물중은 초장과는 달리 EC $7.5dS{\cdot}m^{-1}$에서 감소하였다. 반면 뿌리의 생체중과 건물중은 지상부와는 달리 EC $5.0dS{\cdot}m^{-1}$까지는 차이가 없었으나 EC $7.5dS{\cdot}m^{-1}$서는 매우 감소하였다. 평균과중은 EC $5.0dS{\cdot}m^{-1}$에서 92g으로 EC $1.0dS{\cdot}m^{-1}$ 129g보다 37g이나 가벼웠고 착과수는 평균과중과는 달리 EC $7.5dS{\cdot}m^{-1}$에서는 매우 감소하였다. 수량은 EC 5.0, EC $7.5dS{\cdot}m^{-1}$에서 각각 3,810, 3,216kg/10a로 EC $1.0dS{\cdot}m^{-1}$의 5,488kg/10a보다 각각 31%, 41% 감소하였다. 토마토 과실의 당도와 산도는 염류농도가 높을수록 증가하는 경향이었으며 토양 중 EC $5.0dS{\cdot}m^{-1}$ 이상에서 과실당도가 5.2% 이상 증가하였다. 잎의 수분퍼텐셜 및 엽록소, 기공전도도 및 광합성 함량은 염류농도가 높을수록 억제되었다. 총 T-N, P 및 Na 함량은 염 농도가 높아질수록 증가하는 경향이었으나, Ca, Mg 및 K 함량은 염류농도가 높을수록 감소하였다. Na 함량은 증가하였으며 다른 성분은 처리간에 차이가 없었다.