• Resources Recycling
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• v.30 no.1
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• pp.35-43
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• 2021

In this study, Na2SO4 and KCl reagents were used to synthesize K2SO4 as a basic study for recycling byproducts generated during the manufacture of steel and cement. The mole ratio of Na2SO4 to KCl, the saturation of the solution, and the stirring temperature were controlled to derive the optimal manufacturing conditions. The microstructure and crystallinity of the materials prepared were evaluated using scanning electron microscopy and X-ray diffraction analysis. Pure K2SO4 was obtained when the mole ratio of Na2SO4 to KCl was 1:6-18, the saturation of the solution was less than 160%, and the stirring temperature was 20℃, 50℃. The optimal manufacturing conditions to maximize the crystallinity and yield of K2SO4 while minimizing the energy consumption were 1:6 mole ratio of Na2SO4 to KCl, 140% saturation of the solution, and 20℃ stirring temperature.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.66-72
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• 1983

Anionic polymerization of 2-pyrrolidone was carried out by TDI (Toluene Diisocyanate)/KOH catalysis. The effects of TDI / KOH mole ratio, KOH concentration, temperature and time on polymerization were investigated. It was observed that the highest rate of polymerization and maximum conversion were obtained when TDI / KOH mole ratio was about 0.25. The maximum conversion and the highest viscosity were obtained when the concentration of KOH was 5 mole percent. It was also found that the rate of polymerization and inherent viscosity at $30^{\circ}C$ were higher than those at $50^{\circ}C$. The rate constant ($k_p$) of polymerization was determined by least square method; the values of kp obtained were $57.53{\ell}/mole{\cdot}min\;at\;30^{\circ}C$ and $52.36{\ell}/mole{\cdot}min\;at\;50^{\circ}C$, respectively.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.258-265
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• 2009

An anionic polyurethane dispersions (PUDs) were synthesized from the poly (tetramethylene glycol) (PTMG, Mw = 2000 g/mol), mixed isocyanate of dicyclohexylmethane-4,4'-diisocyanate $(H_{12}-MDI)$ and 4,4'-diphenylmethane diisocyanate (MDI), and dimethylol propionic acid (DMPA) as anionic site, following a prepolymer mixing process. Triethylamine (TEA) was used as a neutralization agent and the ethylenediamine (EDA) as the chain extender of the prepolymer. The effects of the DMPA molar ratio and aromatic diisocyanate content in the mixed isocyanate on the particle size and viscosity of PUD were studied. Also, the mechanical and thermal properties of the PUD cast films were discussed according to the molar ratio of DMPA and aromatic isocyanate content. It was found that the particle size and the viscosity of an anionic PUD decreased with increasing DMPA molar ratio but increased with increasing aromatic isocyanate (MDI) content in the mixed isocyanate at the constant DMPA content. Tensile strength of the PUD cast films increased and elongation at break decreased with increasing DMPA content at the constant mixed isocyanate molar ratios. In thermal degradation temperature of PUD cast films, the effect of DMPA contents was great but the effect of aromatic isocyanate contents at the low DMPA content was very slight respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1113-1120
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• 2011

Enzymatic interesterification was conducted with the palm mid fraction (PMF) and stearic ethyl ester for 1, 5, and 9 hr at 46$^{\circ}C$. The reaction was catalyzed by Lipozyme TLIM (2, 3, and 4% by weight of total substrates) in a shaking water bath at 180 rpm. As the reaction continued, oleic acid (C18:1) content at the sn-2 position decreased, whereas saturated fatty acid (C16:0 and C18:0) content increased. In the high performance chromatography analysis, 1,3-dipalmitoyl-2-oleoyl glycerol content decreased, whereas 1(3)-palmitoyl-2-oleoyl-3(1)-stearoyl glycerol (POS) content increased up to the reaction equilibrium. The rate of acyl migration increased with increasing molar ratio and enzyme load as well as reaction time. The optimal reaction conditions for maximizing POS content (53.5 area%) and minimizing acyl migration (23.1 area%) were obtained with a PMF : stearic ethyl ester=1:2 (molar ratio), Lipozyme TLIM 3 wt%, and a reaction time of 5 hr.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.4
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• pp.479-485
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• 2009

The acidolysis was performed to produce structured lipid with palm mid fraction (PMF) and stearic acid for 7, 24, and 36 hr at $70^{\circ}C$. The reaction was catalyzed by lipozyme TLIM (immobilized lipase from Thermonyces lanuginosa, amount of 10% and 20% by weight of total substrates) in the shaking water bath. The reaction conditions for maximum incorporation of stearic acid on the structured lipid were obtained when molar ratio of PMF and stearic acid was 1:2; concentration of lipozyme TLIM was 20wt%; reaction temperature was $70^{\circ}C$; and reaction time was 36 hr. After reaction under this condition, incorporation of stearic acid in the structured lipid was obtained up to 36.3% while the major components of triacylglycerol were 1,2-dipalmitoyl-3-stearoylglycerol (PPS, 28.19 area%), 1-palmitoyl-2-oleoyl-3-stearoylglycerol (POS/PSO, 20.70 area%) and 1-palmitoyl-2,3-distearoylglycerol (PSS, 18.13 area%). However, the fatty acid composition at the sn-2 position suggested that the positional specificity of lipozyme TLIM was not observed due to the acyl migration.

• Proceedings of the CALSEC Conference
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• 1999.11a
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• pp.108-116
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• 1999

최근 사이버 쇼핑몰에서 기업과 고객간의 제품 구매 활동을 도와주는 검색 에이전트 시스템에 대한 연구가 활성화되고 있다. 그러나 많은 비교 검색 에이전트 시스템들은 고객이 입력한 키워드 기반의 검색 목록만을 체공하고 있으며, 검색된 유사상품 목록 중에서 어떤 상품이 적합한지 선정해 주는 의사결정지원 기능은 충분히 제공하지 못하고 있다 본 논문에서는 인터넷 쇼핑몰 환경을 기반으로 키워드 입력에 의한 제품 검색뿐만 아니라 고객 선호도가 높은 제품 선정을 지원해 주는 의사결정지원 시스템을 제안한다. 제안한 의사결정지원 시스템은 고객이 입력한 각 속성들의 표준계수와 가중치를 점수화 하여 선호도가 높은 상품을 우선적으로 제시함으로써 고객의 상품 선정을 위한 의사결정을 지원하도록 하였으며, 또한 각 속성별 다양한 반영 비율에 따라 어느 제품이 전체적으로 적합한지를 분석하는 민감도 분석 기능을 추가하였다.

• The Journal of the Convergence on Culture Technology
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• v.2 no.4
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• pp.61-64
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• 2016

As the number of smart phone user is increasing, the on-line shopping malls are actively taking part in mobile market, and accelerating the competition of mobile shopping market. This is a reflection of mobile shopping market growing as huge market. This thesis deals with the growth of mobile market and mobile shopping mall application regarding the clothings which occupy high ratio in mobile market. This study aims to improve customer satisfaction based on more specific customer information, and to increase the satisfaction of both company and customer by lowering the return rate.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.537-546
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• 2018

In this paper, we study improvement of web accessibility of Korean Internet shopping mall websites. First, we analyze the criteria of Korean web accessibility, and then evaluate the web accessibility level of major Internet shopping mall websites in Korea. Based on the evaluation of web accessibility level, we propose and implement an alternative text enhancement method using Excel VBA to increase the rate of alternative text for improving web accessibility. Using the proposed method, even non-specialists of web programming can check and modify the alternative text of the image included in web pages, which can help improve the web accessibility compliance rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1224-1231
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• 2006

Sucrose esters were synthesized by transesterification of sucrose with docosahexaenoic acid ethylester mixture (DHAEE). Potassium carbonate as a base catalyst was used in the presence of dimethylsulfoxide (DMSO) for the reactions. The reactions were performed with the different reaction times and molar ratios of substrates in the presence of surfactant in vacuum. Among the reaction conditions in this study, SE#4～7 showed the relatively high conversion rate (>96%) of DHAEE, leading to the high yield of sucrose esters. In addition, the product composition was changed from sucrose mono ester to di/tri/polyesters after the prolonged reaction time while the increased molar ratio of DHAEE also resulted in the composition changes of sucrose mono ester to the sucrose di/tri/polyesters. From the reaction (SE#7), conversion ratio was 98.5% in which 87.3% mono ester and 13.7% di/tri/polyester were found, resulting in the highest content of mono ester. Therefore, the sucrose ester containing various rates of mono and di/tri/polyesters, which effects on hydrophilic lipophilic balance (HLB) values, can be manipulatively synthesized using the reaction conditions reported in this study.

• Membrane Journal
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• v.17 no.4
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• pp.311-317
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• 2007

Proton conducting crosslinked membranes have been prepared by polymer blending, which consist of poly(vinyl alcohol-co-ethylene) (PVA-co-PE) and poly(styrene sulfonic acid-co-maleic acid) (PSSA-co-PMA) at 50 : 50 wt ratio. Two kinds of PSSA-co-PMA copolymer with 3 : 1 and 1 : 1 the molar ratio of PSSA to PMA wereused as a proton conducting source. The ethylene content of PVA-co-PE was also changed as 0, 27 and 44 mol%. The membranes were thermally crosslinked via the esterification reaction between -OH of PVA and -COOH of PMA, as demonstrated by FT-IR spectroscopy (PVA-co-PE)/(PSSA-co-PMA) membranes with 3 : 1 the molar ratio of PSSA to PMA showed higher ion exchange capacity (IEC), lower water uptake and higher proton conductivity than those with 1 : 1 molar ratio. As the PE concentration increased, the IEC values, water uptake and proton conductivities decreased continuously. These properties were elucidated in terms of competitive effect between the concentration of sulfonic acid, hydrophilicity and the crosslinked structure of membranes.