• 대한화학회지
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• 제16권3호
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• pp.157-165
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• 1972

Ammonium metavanadate의 熱分解過程을 spring balance와 示差熱分析에 의하여 調査하였다. 分解는 $180^{\circ}C{\sim}220^{\circ}C$와 $310^{\circ}C{\sim}330^{\circ}C$이 두 溫度範圍에서 일어나며 最終生成物은 $V_2O_5(orange yellow)$임을 알았다. 第一段階分解는 $NH_3$와 $H_2O$가 2:1의 比로 放出되는 過程임을 $NH_3$의 定量, omegatron mass spectrometer에 의하여 알았으며, 第二段階의 分解는 $NH_3,\;H_2$)外에 N2도 放出된다는 것을 gas chromatography, omegatron mass spectrometer에 의하여 認知하였다. 分解生成物을 X-ray 回折에 의하여 分析한 結果는 空氣中에서의 分解生成物은 $V_2O_5$의 組成을 가진 것이 生成되었음을 確認하였다. 또한 $NH_4VO_3$ 熱分解에 있어서의 活性化에너지는 各各 41.4 kcal/mole 64.4 kcal/mole의 값을 갖었음을 알았다.

• 멤브레인
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• 제3권3호
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• pp.126-135
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• 1993

감응물질로 제4급 암모늄염을 사용하여 PVC를 지지체로 과염소산이온의 농도 $10^{-6}M$까지 측정가능한 이온 선택성 전극을 제작하였다. 감응물질의 화학적 구조와 함량, 가소제의 종류 및 막 두께에 따른 선형응답 범위와 Nernst의 기울기 등 전극특성을 검토하여, 최적 막조건을 구한 다음 측정가능 pH범위와 여러 방해이온에 대한 선택계수를 비교 검토하였다. 과염소산 이온선택성 전극에서 감응물질의 화학적 구조 즉, 알킬기의 탄소고리수가 증가할수록 선형응답 범위 등 전극 특성은 Aliquat 336P, TOAP, TDAP 및 TDDAP의 순서로 좋아졌다. 가소제는 DBP가 가장 좋았고, 감응물질의 양은 최적 함량 이상에서 적을수록 좋았다. 최적 막 조성은 TDDAP 9.09, PVC 30.3 및 DBP 60.61wt%이었고, 막두께 0.45mm이었다. 이 조건에서 선형응답 범위 $10^{-1}~1.2 {\times} 10^{-6}M$, 검출한계 $5.1{\times}10^{-7}M$ 및 Nernst기울기 $57mV/pClO_4$이었다. 막전위는 pH 4~11 범위에서 pH의 영향을 받지 않았으며, 선택계수 서열은 다음과 같았다. $SCN^->I^->NO_3^->Br^->ClO_3^->F^->Cl^->SO_4^{2-}$

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.506-510
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• 2004

There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.43-48
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• 2015

Deep eutectic solvents (DESs) are now broadly understood as a new kind of ionic liquid (IL) because they exhibit many characteristics and properties similar with ILs. The DESs made of quaternary ammonium salt blended with one of hydrogen bonding donor (HBD) compounds behave as ILs even at very low temperature. In this study, properties such as density, viscosity, surface tension, conductivity, and electrochemical behavior of DESs were reported and their applications were reviewed. Study on DESs has been drawn attention on application in metal finishing, but these solvents can be used in a variety of synthesis, and their potentials have been demonstrated in various areas. DESs are expected to offer applicability by extending the types of salts and hydrogen bond donor mixtures.

• 한국결정학회지
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• 제5권1호
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• pp.33-38
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• 1994

Hen egg white Iysozyme과 equine serum albumin을 모델 단백질로 하여 'heterogeneous' vapor diffusion실험을 수행하였다. 즉, droplet과 reseroir용액에 각각 다른 침전제를 사용하여 vapor diffusion에 의하여 평형에 이르도록 하였다. 실험 결과는 NSI 혹은 ammonium sulfate 대신 polyethylene glycol이 reservoir 용액에 포함되므로써 droplet과 reservoir 용액 사이의 평형 속도가 감소되는 것을 보여 주었다. Heterogeneous vapor diffusion 법을 통하여 reservoir용액에 포함된 이온성 염과 비이온성 침전제의 양을 적절히 조절하여 평형속도를 조절할 수 있음을 보였다.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.829-834
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• 2010

Ligand variation was carried out on a cobalt(III) complex of Salen-type ligand comprised of 1,2-cyclohexenediamine and salicylaldehyde bearing a methyl substituent on 3-position and -[$CMe(CH_2CH_2CH_2N^+Bu_3)_2$] on 5-position, which is a highly active catalyst for $CO_2$/propylene oxide copolymerization. Replacement of the methyl substituent with bulky isopropyl group resulted in alteration of the binding mode, consequently lowering turnover frequency significantly. Replacement with an ethyl group preserved binding mode and activity. Replacement of the tributylammonium unit with trihexylammonium or trioctylammonium, or replacement of 1,2-cyclohexenediamino unit with -$NC(Me)_2CH_2N$- decreased activity, even though the binding mode was unaltered.

• 한국추진공학회지
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• 제3권1호
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• pp.48-54
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• 1999

질산암모늄(AN)과 potassium dinitramide(KDN)의 수용액으로부터 염석법에 의해 상안정화 질산암모늄(PSAN)을 제조하는 방법을 나타내었다. 침전제로 사용된 유기 용매는 아세토니트릴이었다. 침전된 결정들의 DSC 분석결과 이들 결정들이 PSAN임을 확인하였고, 침전된 결정중의 KDN 함량이 약 6 무게 % 이상일 때 $0^{\cire}C$에서 $80^{\cire}C$의 온도 범위내에서 AN이 안정화되었다. 제조된 결정들은 고체 로켓 추진제 및 폭약 둥의 제조에서 산화제로 사용될 수 있을 것이다.

• 한국환경과학회지
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• 제20권1호
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• pp.119-126
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• 2011

In this study, reaction model and reactions rate accelerated by o-iodosobenzoate ion(IB$^{\ominus}$) on hydrolysis reaction of p-nitrophenyl valate(NPV) using ethyl tri-octyl ammonium mesylate(ETAMs) for quaternary ammonium salts, the phase transfer catalysis(PTC) reagent, were investigated. The effect of IB$^{\ominus}$ on hydrolysis reaction rate constant of NPV was weak without ETAMs solutions. Otherwise, in ETAMs solutions, the hydrolysis reactions exhibit higher first order kinetics with respect to the nucleophile, IB$^{\ominus}$, and ETAMs, suggesting that reactions are occurring in small aggregates of the three species including the substrate(NPV), whereas the reaction of NPV with OH$^{\ominus}$ is not catalyzed by ETAMs. Different concentrations of NPV were tested to measure the change of rate constants to investigate the effect of NPV as substrate and the results showed that the effect was weak. This means the reaction would be the first order kinetics with respect to the nucleophile. This behavior for the drastic rate-enhancement of the hydrolysis is referred as 'Aggregation complex model' for reaction of hydrophobic organic ester with o-iodosobenzoate ion(IB$^{\ominus}$) in hydrophobic quarternary ammonium salt(ETAMs) solutions.

• 한국식품영양과학회지
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• 제28권4호
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• pp.755-759
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• 1999

To evaluate the effect of sterilizing method on the quality of iron fortified market milk, HTST(high temperature, short time) or LTLT(low temperture, long time) method was adopted after addition of 100ppm ferrous sulfate, ferric citrate, ferric ammonium citrate, or ferrous lactate in market milk. Sterilized iron fortified market milk was stored at 4oC and then pH, lipid oxidation, color change, and sensory quality were observed. The range of pH change in iron fortified market milk sterilized by HTST or LTLT was 6.51~6.74. The order of pH was control>ferric ammonium citrate>ferrous lactate>ferrous sulfate>ferric citrate. Oxygen consumption of ferric ammonium citrate and ferric citrate was lower than ferrous lactate and ferrous sulfate. This trend was same in HTST and LTLT method, but generally oxygen consumption was lower in iron fortified market milk sterilized by LTLT method than by HTST. In total color change, ferrous lactate treatment was closer to control than other treatments. Also sensory characteristics of ferrous lactate treatment was showed better quality than other treatment. From these results, LTLT method was more suitable than HTST method for iron fortified market milk and ferrous lactate was comparably suitable among iron salts used in this study.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.250.3-251
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• 2003

A series of cinchona alkaloid-derived dimeric quaternary ammonium salts were prepared as chiral phase-transfer catalysts by the introduction of various functional groups on the phenyl ligand. Among them. the 2-F-substituted derivative 21 showed the highest enantioselectivity in the alkylation of the glycine anion equivalent 1 (97->99 ％ ee).