• Applied Biological Chemistry
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• v.26 no.2
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• pp.125-131
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• 1983

Formal net charges, bond populations, atomic orbital coefficients, energy components and conformation of dimethyl-2,2-dichlorovinylphosphate have been studied theoretically by using the CNDO/2 molecular orbital calculation method in attempt to describe the reactivity and the stability of the molecule. From the analysis of rate equation, molecular orbital calculations and identification of the hydrolysis products, 2,2-dichloroacetaldehyde and dimethylphosphoric acid, a mechanism of the hydrolysis of dimethyl-2,2-dichlorovinylphosphate(DDVP) has been proposed. The hydrolysis of DDVP proceeds through the mechanism of nucleophilic addition, typical Micheal reaction in basic media. Therefore, it appears probable that the attack by strong nucleophile, hydroxide ion occurs at the increased positive charge $C_2({\alpha})$ atom of a staggered conformation due to the inductive effect (-)I>(+)R of 2,2-dichlorovinyl, electron-attracting group. And then, the hydrolytic scission involves the $C_2({\alpha})-O_3$, ${\pi}-anti-bonding\;orbital({\pi}^*)$ in the subsequent reaction in aqueous solution.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.513-522
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• 2019

Catalysts based on organic compounds, transition metal and metal-organic frameworks (MOFs) have been applied to degrade or remove organophosphorus toxic compounds (OPs). During the last 20 years, various MOFs were designed and synthesized to suit application purposes. MOFs with $Zr_6$ based metal node and organic linker were widely used as catalysts due to their tunability for the pore size, porosity, surface area, Lewis acidic sites, and thermal stability. In this review, effect on catalytic efficiency between MOFs properties according to the structure, stability, particle size, number of connected-ligand, organic functional group, and so on will be discussed.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.1
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• pp.51-58
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• 1999

The effects of glass composition on the wettability and reactivity with $ZrO_2$substrate was evaluated and fabrication variables and glass compositions was investigated. Various glass compositions was investigated. Alkaline earth silicate glass show good wettability and lower viscosity and crystallization of glass could be prevented by $B_2O_3$.The sealant glass begin to wet on $ZrO_2$substrate below $900^{\circ}C$ and porosity occurred in various glass compositions, the crystallization and porosity in the glass could be prevented by the addition of flux into glass composition. But flowability and reactivity of glass with $ZrO_2$substrate was enhanced. Processing variables should be optimized to reduce the porosity by enhancing the sintering of glass powder. Many silicate glasses were investigated for the applications of high temperature sealants. Wetting and bonding of glass was good enough to seal together between $ZrO_2$and other ceramic components of SOFC. But porosity and reaction layer were occurred in the sealant glass. It will be possible to produce glass sealant without porosity and reaction layer at the interface by optimization of processing variable and modify the glass compositions. In present study, wettability of glass-filler composite was investigated. The porosity, shape of filler and interfacial reactions of sealant glass with fillers were examined.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.531-536
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• 2019

In this study, the optimization of the manufacturing process for the oil-in-water emulsification of rice bran oil was performed by response surface methodology (RSM) using varying amounts of the emulsifier (0.05-0.25%), varying rotation speeds of the homomixer (4,000-8,000 rpm), and varying water to oil ratios (0.8-1.6%) as independent variables, and the emulsion stability index (ESI) as the dependent variable. The optimization conditions predicted by the RSM model were 0.2%g of the total amount of the rice bran oil emulsion, emulsified at the homomixer rotation speed of 6,700 rpm using a water to oil ratio of 1:3. The ESI of the rice bran oil emulsion prepared under the optimized conditions was 95.7%, which was similar to the predicted value of 94.4% obtained by the RSM model. The transmission stability and the backscattering values were found to agree with each other over time and the turbiscan stability index was less than 0.7, indicating that the aggregation and upper floatation were less while the dispersion stability was maintained.

• Membrane Journal
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• v.30 no.4
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• pp.252-259
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• 2020

Olefins are industrially important materials used for the synthesis of various petrochemicals. During the polymerization process, unreacted olefin monomers are discharged together with a large amount of nitrogen. For economic benefits, these olefin gases should be efficiently separated from nitrogen. In this study, a poly(glycidyl methacrylate-co-methyl methacrylate) (PGM) comb-like copolymer was synthesized and 4,4'-diaminoazobenzene (DAAB) was introduced to the copolymer to prepare a cross-linked membrane for C₃H₆/N₂ separation. PGM and DAAB were readily reacted at room temperature through an epoxide-amine reaction without additional thermal treatment. PGM-based membrane, which is a glassy polymer, showed a faster permeation of N₂ compared to C₃H₆. The pristine PGM membrane exhibited the N₂ permeability of 0.12 barrer and the high N₂/C₃H₆ selectivity of 32.4. As DAAB was introduced as a cross-linker, the thermal stability of the membrane was significantly improved, which was confirmed by TGA result. The N₂/C₃H₆ selectivity was decreased at 1 wt% of DAAB content, but the N₂ permeability increased by approximately 4.7 times. We analyzed N₂/C₃H₆ gas separation properties through a glassy polymer-based membrane, which has not been widely studied. Also, we proposed that thermal stability of the membrane can be greatly improved by the cross-linking method.

• Polymer(Korea)
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• v.35 no.3
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• pp.249-253
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• 2011

The effect of morphological development in PET/PEN blending on the physical properties of PET/PEN blend film as a flexible substrate was investigated. The two phase morphology was obtained in PET/PEN blends and it caused the improvement of dimensional stability of PET/PEN blend as a flexible substrate. The two phase morphology and crystallinity of PET/PEN blends could be controlled by the transesterification between PET and PEN during the film processing and this macroscopic structural development affected the dimensional stability of PET/PEN blend films. Better dimensional stability was obtained with increasing crystallinity and decreasing the level of transesterification.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.489-492
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• 2002

고분자/금속 복합재료는 현대 전자산업에 중요한 역할을 하고 있다. 그러나 이들간의 계면은 고분자의 수축 또는 계면 안정성의 저하로 인하여 박리가 일어나게 된다. 즉, 계면의 접합이 떨어지게 되면 전기 화학적인 반응이 계면에서 발생하여 드러난 금속부위는 산화되고 산소가 환원될 때 발생하는 OH기와 같은 라디칼들에 의해 금속과 고분자 사이의 결합이 파괴되어 금속표면으로부터의 고분자의 박리가 발생한다. (중략)

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.513-516
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• 2003

고체상 풀림과 재접힘 공정을 통해서 EK의 활성이 회복되어지는 것을 확인할 수 있었다. 이는 고정화 효소를 사용함으로써 기존의 액상반응에서 불가능한 효소의 재사용 문제를 해결할 수 있다. 친화도보다는 다중 공유결합을 통한 효소의 고정화가 효소의 활성 회복에 높은 안정성을 가질 수 있다고 예상한다.

• Proceedings of the KSEG Conference
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• 2004.03a
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• pp.11001-11050
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• 2004

불연속면 또는 단열은 암반 내의 역학적 분리면을 통칭하는 것으로서 암반 내의 작은 흠집이나 물리적으로 불균질한 곳이나 불연속면 주위에 응력이 집중되어 초래되는 변형의 결과이다. 불연속면은 정압, 지체구조적, 그리고 열적 응력 및 높은 수압에 반응하여 형성되며, 아주 미세한 것부터 대륙 규모에 걸쳐 다양한 크기로 발달한다. 불연속면은 연속체로서의 암반을 물리적으로 분리시키기 때문에 그 자체로서 역학적인 약대에 해당되고, 지하수의 유동 통로의 기능도 하기 때문에 지질공학, 지반공학 및 수리지질학 실무에서 매우 중요한 요소로 작용한다. 경제적으로 중요한 석유, 지열 및 수자원 저류체 역시 단열 암반 내에 형성된다. 불연속면은 오염물질의 이동과 분산을 제어할 뿐만 아니라 암반을 기초로 하거나 대상으로 하는 공학적 구조물과 굴착의 안정성에도 역시 영향을 미친다. (중략)

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.996-1000
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• 2016

Effects of copigments (succinic acid, $Cu^{2+}$, ascorbic acid, sucrose, and pH) on stability of anthocyanin extracted from black beans (Glycine max Merrill.) were investigated during storage for 8 days at 4 and $40^{\circ}C$. Succinic acid improved stability of anthocyanin by 7~15% compared to the non-treatment group at $40^{\circ}C$. $Cu^{2+}$ maintained stability of anthocyanin by about 100% for 8 days at $4^{\circ}C$. Ascorbic acid reduced stability of anthocyanin by 64~72% of non-treatment at $40^{\circ}C$. Sucrose treatment did not significantly affect stability compared to the control. The lower pH improved stability of anthocyanin. Stability at pH 1 was improved by 81~87% compared to that at pH 7. These results show that temperature, organic acid, and pH were effective in improving storage stability of anthocyanin from black beans.