• Fibers and Polymers
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• v.1 no.1
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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.

• Journal of ILASS-Korea
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• v.20 no.3
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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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• v.35 no.10
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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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• v.24 no.1
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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.

• Journal of Advanced Technology Convergence
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• v.3 no.2
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• pp.39-44
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• 2024

This study was prepared for a natural aroma solution for the purpose of improving depression, anxiety, and insomnia caused by stress in modern people, and applied the solution to wet tissues. Specifically, the pine oil solution was prepared by mixing Korean pine oil and black cherry oil. Heavy metal analysis, antibacterial analysis, psychological evaluation, and skin evaluation were performed on the prepared pine oil solution to examine the possibility of manufacturing functional aroma wet tissues for stress improvement. Furthermore, as a result of investigating whether pine oil solution wet tissues improved the skin, it was found that there was an improvement effect in terms of moisturizing and elasticity.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.685-688
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• 2001

We prepared D,L-phenylalanine imprinted membrane by a wet phase method. Template was imprinted in the step of copolymerization or implanted by mixing template and DMSO solution containing copolymer. The adsorption selectivity of each membrane was investigated.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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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.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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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.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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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.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.10a
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• pp.107-107
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• 2003