• Product Safety
• /
• s.100
• /
• pp.40-42
• /
• 2002

• KSBB Journal
• /
• v.25 no.3
• /
• pp.251-256
• /
• 2010

A novel method to prepare polyester from wastepaper through liquefaction and crosslinking stages was studied. At the first stage, the liquefaction of wastepaper was carried out in the presence of ethylene glycol under acidic conditions. The factors that affect on liquefaction yield were found to be reaction time, temperature, and acid concentration, and their ranges were 60~120 minutes, $150{\sim}170^{\circ}C$, and 2~4%, respectively. The optimum condition was found to be 100 minutes, $160^{\circ}C$, and 3% sulfuric acid concentration, and the liquefaction yield at this condition was 67%. At the second stage, polyester was prepared from the liquefied wastepaper obtained at the optimum liquefaction condition by crosslinking with succinic anhydride. The effect of reaction time and carboxylic group/hydroxyl group ratio on crosslinkage were investigated at conditions covering 30~50 minutes of reaction time and 1.5~2.5 of carboxylic group/hydroxyl group ratio. The crosslinkages of polyester prepared were 80~90%, which were almost same regardless of reaction conditions.

• Journal of the Korea Concrete Institute
• /
• v.21 no.6
• /
• pp.729-735
• /
• 2009

In this study, it is experimentally verified a feasibility of the wasted phosphogypsum ($CaSO_4/H_2O$) that is a byproduct from the phosphoric acid process of manufacturing fertilizers can be applied as an admixture in slag cement. For the test, phosphogypsum is modified as dihydrate, hemihydrate, type III anhydrite, and type II anhydrite, and then chemical characteristics and mechanical properties of various slag cements containing above mentioned gypsum materials were analyzed. The test results show that the gypsum made at high temperature has better quality with decrease of water-soluble phosphoric acid ($S-P_2O_5$) which has an effect on the quality of cement. And type II anhydrite shows superior quality in terms of drying shrinkage and the compressive strength of cement paste with hemihydrate at 56 days is higher than other gypsum material.

• Membrane Journal
• /
• v.28 no.4
• /
• pp.271-278
• /
• 2018

In this study, the carbon electrodes using activated carbon fibers (ACFs) were prepared for the capacitive deionization process. The Polyvinylidene fluoride (PVDF) was used as the binder and the mixed ACFs with proper solvent was cast on the commercial graphite sheets to prepare the carbon electrodes. At this moment, the different particle sizes of ACFs were applied and the mixing ratio of solvent, PVDF and ACFs, 80 : 2 : 18 and 80 : 5 : 15, were used for the electrode preparation. Then their salt removal efficiencies were characterized under the various operating conditions, adsorption potential and time, desorption potential and time, concentration of feed NaCl solution and flow rate as well. Typically, the salt removal efficiency of 53.6% were obtained at the particle size below $32{\mu}m$, mixing ratio 80 : 2 : 18, adsorption 1.2 V and 3 min, desorption -0.1V and 1 min, and 15 mL/min flow rate of NaCl 100 mg/L.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.71.1-71.1
• /
• 2011

석석탄가스화 기술은 고온, 고압 조건에서 미분탄과 산소의 가스화 반응에 의해 CO와 $H_2$가 주성분인 합성가스를 제조하는 기술로서 차세대 화력발전 뿐만아니라 다양한 화학원료 제조를 위한 분야에서 각광을 받고 있다. 또한, 가스화 기술은 향후 CCS기술, CTL(Coal To Liquid, 석탄액화)기술, SNG(Synthetic Natural Gas, 합성천연가스)생산, 수소생산, 각종 화학원료 생산 등과 연계가 가능한 미래 석탄이용 분야의 핵심 기술이라 할 수 있다. 따라서, 고등기술연구원에서는 이러한 석탄가스화를 통해 양질의 합성가스를 제조하기 위한 기술 개발의 일환으로 pilot급 고온, 고압 건식 분류층 가스화기, 기류수송 방식의 미분탄공급장치, 수냉자켓 구조의 합성가스 냉각장치, 합성가스 중 분진제거를 위한 금속필터 장착 집진장치 등을 연계하여 20기압의 고압 조건에서 장시간 연속운전을 진행하였다. 본 연구에서는 미분탄 공급을 위하여 상부공급 버너를 적용하였고 석탄가스화기는 $1,300{\sim}1,350^{\circ}C$ 정도의 온도에서 운전을 진행하였으며 미분탄을 75 kg/h의 조건에서 연속적으로 공급하였다. 그리고, 이러한 조건에서 5.5일 정도의 연속운전을 진행하는 동안 CO 44~48%, $H_2$ 20~21%, $CO_2$ 4~5% 조성의 석탄 합성가스를 $200Nm^3/h$ 안정적으로 제조할 수 있었다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.1
• /
• pp.62-69
• /
• 2009

Maillard reaction products (MRPs) were produced from aqueous solution of various sugars with defatted hydrolyzed soybean protein (DFHSP) with different temperatures and pressures. Physicochemical properties of MRPs were investigated; also, DPPH and hydroxyl radical scavenging activity and sensory properties were evaluated. MRPs from ribose and DFHSP had the highest reactivity with larger pH reduce, higher browning index increase and higher antioxidant activity than other MRPs from other sugars. The antioxidant activities were increased with increasing temperatures and pressures of reaction. The highest antioxidant activity and sensory preference were obtained from MRPs with ribose at $140^{\circ}C$ with 2.8 kg/$cm^2$ for 30 mins.

• Journal of Food Hygiene and Safety
• /
• v.35 no.1
• /
• pp.83-92
• /
• 2020

This study investigated the optimal conditions of enzymatic reaction for production of isomaltooligosaccharides (IMO) using rice flour. To manufacture IMO, commercial enzymes (Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L and Transglucosidase L) were used. The sugar composition and amount of IMO were examined by HPLC with charged aerosol detector (HPLC-CAD) in each manufacturing process. Liquefaction reaction was performed according to different Termamyl 2X concentrations (0.025%, 0.05%, 0.075%, 0.1%) and reaction times (1 h, 2 h). As a result, the reducing sugar content was the highest at 138.26 g/L when 0.075% Termamyl 2X was added for 2 hours. In order to optimize simultaneous saccharification and transglucosylation, experiments on enzyme selection, enzyme concentration and enzyme reaction time were conducted. Reaction with 0.0015% Maltogenase L, 0.05-0.1% Promozyme D2 and 0.1% Tansglucosidase L was effective in decreasing glucose content and increasing content of IMO with a high degree of polymerization. A change in sugar content was observed every 6 hours to determine the optimal reaction time, and the highest IMO was produced after 36 hours of reaction (75.36 g/L). The IMO prepared under optimal conditions showed isomaltose, 35.11 g/L; panose, 11.97 g/L; isomaltotriose, 19.95 g/L; isomaltotetraose, 7.46 g/L; isomaltopentaose, 1.05 g/L at 18 brix and the ratio of IMO in the total sugar was 56.37%.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1993.10a
• /
• pp.24-24
• /
• 1993

세라믹 분리막은 기존의 유기질막에 비하여 고온 분리공정이 가능하고, 기계적 강도가 크며, 화학 물질에 대해서도 안정하므로 유기질막이 사용 되어질 수 없는 공정 조건에서도 사용이 가능하다. 그러나 기존의 제조법으로 제조한 세라믹 분리막은 복합 분리막의 경우, 코팅시 분리막층에 미세균열이 쉽게 발생하고 막의 재현성이 좋지 않기 때문에 새로운 분리막 제조 공정의 개발 필요성이 대두되고 있다. 본 실험은 이러한 목적하에 반도체 공업에서 주로 사용되어지고 있는 화학기상증착법을 이용하여 세라믹 복합 분리막을 제조하였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.624-624
• /
• 2013

본 연구에서는 전자빔 조사를 이용하여 대기 조건에서 실리카 나노입자를 제조하였다. 제조된 실리카 나노입자는 FT-IR을 통해 전구체가 전자빔에 의하여 분해되었음을 확인하였고 또한 XPS를 통해 Si 2P binding energy가 확인되었다. 본 연구에서 제조된 나노입자의 평균 지름은 각각 210 nm와 73 nm로 나타났고, 입자의 평균지름은 전구체 증기의 전자빔 반응기내 체류시간 조절에 따라 제어된다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.625-625
• /
• 2013

본 연구에서는 전자빔 조사를 이용하여 대기조건에서 중공 실리카 나노입자의 새로운 기체상 단일 공정 제조 방법을 제시하였다. 실험에서는 전구체로서 TEOS와 은 나노입자가 사용되었다. EDS 분석 결과 실리카 중공 나노입자의 제조를 확인하였으며, TEM 분석을 통해 제조된 중공나노입자의 평균 지름과 쉘 두께가 각각 56 nm와 10 nm임을 알 수 있었다.