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        검색결과 4

        1.
        2013.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study was performed with an aim to improve the early-age strength of concrete containing fly ash, which is known to increase the long-age strength of concrete, reduce drying shrinkage, and enhance water tightness. The composition was partially substituted with calcium sulfoaluminate (CSA), from which ettringite is actively produced, in the early stages of hydration to verify its effect on improving the early-age strength and to determine the optimal mixing ratio. For this purpose, up to 30 % of the cement weight was substituted with fly ash, and the amount of CSA substitution was 8% of the fly ash weight. The mixtures were then fabricated into concrete specimens for compressive strength measurement and analysis of the correlation between the hydration products and the compressive strength.
        4,000원
        2.
        2011.05 구독 인증기관·개인회원 무료
        Alzheimer’s disease (AD) is a fatal disorder wherein patients suffer from sensory, motor, and cognitive loss. Currently, the identification and validation of biomarkers for diagnosing AD and other forms of dementia are increasingly important. Olfactory dysfunction is present in patients diagnosed with Alzheimer’s disease or idiopathic Parkinson's disease. Alzheimer’s patients show neuropathological changes in areas of the brain central to the olfactory processing center, suggesting the theoretical importance and potential diagnostic utility of investigating functional changes in olfaction in these patients. However, the usefulness of olfactory screens to serve as informative indicators of Alzheimer’s is precluded by the lack of knowledge regarding neural and molecular mechanisms underlying olfactory dysfunction onto Alzheimer's diseases. To test these ultimate questions, we used molecular and electrophysiological recording techniques to find out the difference of olfactory responses and AD related protein expression patterns by using fly model, Drosophila melanogaster that over-expresses the human β -amyloid, tau protein. We postulated that such flies would present with progressive olfactory impairments compared with age-matched wild type control flies. In this study, our hypothesis is that there is a correlation between olfactory deficits and the spatial expression pattern of β-amyloid and tau protein deposition. Therefore, we demonstrate a specific concentration of lesions in central olfactory structures such as antenna and Maxillary palps. Our study indicates that deficits on olfactory identification may occur in AD, which will be valuable as an indicator of neuropathogenesis.
        3.
        2018.10 서비스 종료(열람 제한)
        In this study, the temperature correction strength (Tn) was conducted to propose (Tn) according to the management age of structural concrete that is separated from the average curing temperature of 4°C to 17°C in cold conditions. After reviewing the strength difference of the concrete using fly ash as a combined material at W/C 50%, the temperature correction strength (Tn) is proposed. The temperature correction strength was proposed to compensate for differences with standard curing conditions due to decrease in curing temperature from 28th, 42nd, 56th and 91st of the models interpreted as equivalent age methods.
        4.
        2018.03 KCI 등재 서비스 종료(열람 제한)
        시멘트 산업은 탄소배출 감축을 위한 주요 산업분야로 고려되고 있으며, 콘크리트 분야에서 시멘트 사용량 저감을 위한 노력이 진행되고 있다. 이에 대한 노력의 일환으로 시멘트의 일부를 대체하여 사용할 수 있는 산업부산물을 다량으로 활용하기 위한 연구가 진행되고 있다. 산업부산물을 사용한 콘크리트는 내구성, 친환경성 및 경제성 등의 장점을 가지고 있으나, 응결시간 지연, 초기강도 저하 등의 문제점이 있다. 따라서 이 연구에서는 시멘트의 사용량을 줄이고 산업부산물인 플라이애시를 치환하여 사용하면서도 초기강도가 저하되는 문제점을 해결하는 것을 목표로 하였다. 이에 따라, 먼저 고분말도 시멘트 사용에 의한 수화반응 촉진으로 양생온도에 관계없이 모든 재령에서 강도가 증진되는 것을 확인하였다. 이어서 고분말도 시멘트에 플라이애시를 치환하여 강도발현 특성을 검토한 결과, 초기 재령에서도 보통 포틀랜드 시멘트와 비교하여 동등 이상의 강도 발현이 가능하였다. 또한, 플라이애시를 30%까지 치환하여도 수직․수평부재 거푸집 해체 시기를 단축할 수 있는 것을 확인하였다.