Geopolymer, also known as alkali aluminum silicate, is used as a substitute for Portland cement, and it is also used as a binder because of its good adhesive properties and heat resistance. Since Davidovits developed Geopolymer matrix composites (GMCs) based on the binder properties of geopolymer, they have been utilized as flame exhaust ducts and aircraft fire protection materials. Geopolymer structures are formed through hydrolysis and dehydration reactions, and their physical properties can be influenced by reaction conditions such as concentration, reaction time, and temperature. The aim of this study is to examine the effects of silica size and aging time on the mechanical properties of composites. Commercial water glass and kaolin were used to synthesize geopolymers, and two types of silica powder were added to increase the silicon content. Using carbon fiber mats, a fiber-reinforced composite material was fabricated using the hand lay-up method. Spectroscopy was used to confirm polymerization, aging effects, and heat treatment, and composite materials were used to measure flexural strength. As a result, it was confirmed that the longer time aging and use of nano-sized silica particles were helpful in improving the mechanical properties of the geopolymer matrix composite.

목 적: 본 연구는 고함수 하이드로젤 렌즈를 제조하기 위해 일반적으로 사용되는 콘택트렌즈의 재료와 MPTS(methacryloxypropyl tris(trimethylsiloxy)silane) 및 DMA(N,N-dimethylacrylamide)를 각각 첨가하여 중합한 후 이 재료들의 첨가 비율을 증가시켜 물리적 특성을 평가하였다. 방 법: MPTS와 DMA를 교차결합제인 EGDMA와 HEMA, NVP, MMA 그리고 개시제인 AIBN을 사용하여 캐스트 몰드법으로 공중합 하였다. 결 과: 실험결과, DMA를 첨가하여 제조한 콘택트렌즈의 함수율은 43.32~64.65%, 산소전달률(Dk)은 13.55~33.55×10(-11)(cm2/sec)(mlO2/ml×mmHg)이었다. MPTS를 첨가하여 제조한 콘택트렌즈의 경우, 함수 율은 41.02~47.62%, 산소전달률(Dk)은 13.88~20.38×10-11(cm2/sec)(mlO2/ml×mmHg)이었다. DMA가 첨가된 조합에서는 함수율이 증할수록 산소전달률(Dk)이 증가하는 경향을 보였지만 MPTS가 첨가된 조합에서는 함수율이 증가하여도 산소전달률(Dk)은 일정하게 유지되는 경향을 보였다. 결 론: 본 실험결과로 볼 때 생성된 공중합체는 고함수율을 가진 안의료용 재료로 사용될 수 있을 것으로 판단된다.

Weather forecasting is one of the key elements to improve health through the prevention and mitigation of health problems. Health forecasting is a potential resource creating enormous added value as it is effectively used for people. The purpose of this study is to estimate 'Willingness to Pay' for health forecasting. This survey was carried out to derive willingness to pay from 400 people who lived in Busan and Kyungnam Province and over 30 years of age during the period of July 1-31, 2009. The results showed that a 47.50% of people had intention to willingness to pay for health forecasting, and the pay was 7,184.21 won per year. Willing to pay goes higher depending on 'tax burden as to benefit of weather forecasting', 'importance of the weather forecasting in the aspect of health', 'satisfaction to the weather forecasting', and 'frequency of health weather index check'. This study followed the suggestion of the Korea Meteorological Administration generally and the values derived through surveys could be reliable. It can be concluded that a number of citizens who are willing to pay for health forecasting are high enough to meet the costs needed to provide health forecasting.