• Fibers and Polymers
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• 제1권1호
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• pp.6-11
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• 2000

In the polycondensation reaction of polyethyleneterephthalate(PET), $Sb_2$$O_3$, can react effectively as a catalyst, if physically transformed. $Sb_2$$O_3$ powder is transformed into liquid solution by dissolving in ethylene glycol(EG). Homogeneous catalyst is made by mixing this liquid solution with glycols having different solubility. The efficient reaction of PET polymerization is expected by using homogeneous catalyst. PET was synthesized using homogeneous catalysts of 4 wt.% $Sb_2$$O_3$ solution dissolved in glycol[EG, 2,2-bis(4-(2-hydroxyethoxy)phenol)propane(BHPP), neopentyl glycol(NPO), and 1,3-propandiol(PD)]. PET using EG-BHPP($Sb_2$$O_3$) catalysts shows the highest I.V. within a reaction time of 120 min. In the p-d analysis, PET using EG-BHPP($Sb_2$$O_3$) catalysts has the fastest propagation rate and slowest degradation rate. EG-BHPP($Sb_2$$O_3$) catalysts are more efficient than EG($Sb_2$$O_3$) catalysts and $Sb_2$$O_3$ powder catalysts.

• 한국분무공학회지
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• 제20권3호
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• pp.162-167
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• 2015

Recently, there has been rising interest in applying urea-SCR systems to large marine diesel engines because the International Maritime Organization (IMO) has decided to enforce NOx reduction regulations. Generally, in the case of urea-SCR of the marine diesel engine, a type of twin fluid atomizer has been using for injection of the urea solution. This study conducted to investigate an effect of the atomization of external-mixing twin fluid nozzle on the conversion efficiency of reductant. The lab-scaled experiment device was installed to mimic the urea-SCR system of the marine diesel engine for this study. In a low temperature inflow gas condition which is similar with the exhaust temperature of large marine diesel engine, this study found that the conversion efficiency of reductant of when relative big size urea solution droplets are injected into exhaust gas stream can be larger than that of when small size urea solution droplets are injected. According to results of this study, the reason was associated with decrease of reaction rate constant caused from temperature drop of inflow gas by assist air of twin fluid atomizer.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.3015-3020
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• 2014

The behavior of benzo[a]pyrene-7,8-dione (BPQ) in aqueous solution and its interaction with native DNA was investigated using conventional absorption and linear dichroism (LD) spectroscopy. The appearance of a broad absorption maximum at long wavelengths and its proportional relationship to solvent polarizability suggested that BPQ adopts a aggregated state for all solutions examined. Disappearance of this absorption band at higher temperatures in aqueous solution also supported BPQ aggregation. When associated with DNA absorption spectral properties were essentially the same as that in aqueous solution. However, two isosbestic wavelengths were found in the concentration-dependent absorption spectrum of the BPQ-DNA complex, suggesting the presence of at least two or more DNA-bound BPQ species. Both species produced $LD^r$ spectra whose magnitude in BPQ absorption region is larger or comparable to that in the DNA absorption region, suggesting that the molecular BPQ plane is near perpendicular relative to the local DNA helical axis. Therefore, BPQ molecules are aligned along the DNA stem in both DNA-aggregated BPQ species.

• Computers and Concrete
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• 제24권1호
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• pp.1-6
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• 2019

Within the scope of this study, the foam solution was prepared by properly mixing sulfonate based foam agent with water. Furthermore, this solution was mixed with the mixture of fine sand, cement, and water to produce foamed concrete. The mixture ratios which are the percentage of foam solution used in foam concrete were chosen as 0, 20, 40 and 60% by vol. After these groups reached 28 days of strength, they were heated to 20, 100, 400 and $700^{\circ}C$ respectively. Afterward, high-temperature effects on the foamed concrete were obtained by employing physical and mechanical properties tests. Additionally, SEM (scanning electron microscope) and EDX (energy-dispersive X-ray spectroscopy) tests were employed to analyze the microstructure, and ${\mu}-CT$ (micro computed tomography) images were used to reconstruct 3-D models of the heat-treated specimens. Then, these models are analyzed to examine the void structures and the changes in these structures due to the high temperatures. The study has shown that the void structures reduce the high-temperature effects and the foam solution could be mixed with concrete up to 40 % by vol. where the high strength of foamed concrete is non-mandatory.

• 미래기술융합논문지
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• 제3권2호
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• pp.39-44
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• 2024

본 연구는 현대인의 스트레스로 인한 우울증, 불안, 불면증을 개선할 목적으로 천연 아로마 솔루션을 개발하고, 그 솔루션을 이용하여 물티슈에 응용하였다. 구체적으로, 소나무오일 솔루션는 한국산 소나무 오일과 블랙체리 오일를 혼합하여 제조하였다. 제조한 소나무 오일 솔루션에 대하여, 중금속 분석, 항균 분석, 심리 평가 및 피부 평가를 수행하고 스트레스 개선용 기능성 아로마 물티슈 제조 가능성을 검토하였다. 더나아가, 소나무오일 솔루션 물티슈의 피부 개선 여부를 조사한 결과, 보습 및 탄력 측면에서 개선의 효과가 있는 것으로 나타났다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.685-688
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• 2001

분자각인 막에 대한 선택적인 홉착을 알아보기 위해서 우리는 템플릿을 바꾸어 보기도 하고 중합방법과 세척조건을 다르게 하였다. 결과에서 우리는 템플릿 탈착에는 아세트산 10% 수용액으로 세척한 경우 가장 우수한 회수도를 보였다. 그러고 In-situ implanting method가 post implanting method에 비해 약 1.8 나 더 나은 선택 흡착성을 보였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.9-10
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• 2003

Cellulose/chitosan and sericin/chitosan blend films with various mixing ratios were prepared and tensile properties, solubilities to the aqueous solution of acetic acid and the degree of swelling by the distilled water were measured. The interaction between the components of blend film and the blending effect were investigated.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.292-292
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• 2006

A two-step process of the solution blending and the subsequent melt mixing in a Brabender mixer was used to prepare clay nanocomposites of SAN/PVC and of ABS, respectively. It was found that the new method was effective in obtaining well-dispersed nanocomposites for both cases. The glass transition behavior of the organoclay nanocomposites were analyzed by using theoretical equations. The interaction characteristics were evaluated by using the solubility parameters estimated from the group molar attraction constants.

• 한국응용과학기술학회지
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• 제14권2호
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• pp.103-114
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• 1997

Metachromatic properties of admixture of methylene blue(MB) and thionine in aqueous solution has been studied by fluorescence spectroscopy. In spite of nonfluorescence character has been MB itself, mixing MB to monomeric concentration of thionine, new coaggregation band has been formed in shorter wave length than fluorescence of thionine because of MB was redistributed to thionine aggregate. It suggested that coaggregate of MB and thionine were more tightly formed than the each dye aggregate.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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• pp.107-107
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• 2003