http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
액체의 밀도가 입자를 포함한 댐 붕괴 유동에 미치는 영향성 평가
김민일(Min Il Kim),윤현식(Hyun Sik Yoon) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
The present study investigated the dam break flow containing the particles. To investigate the effect of liquid density, liquid density of wide range is considered in this study. Two region of the overlapping and divergent govern the time evolution of the particles and the free-surface. The overlapping regime shows that the front head positions of the liquid and the particles are almost identical and two dimensional behaviors. However, in the divergent regime, lower liquid densities derive that the front head of liquid is faster than that of the particle. Beyond the critical liquid density, the opposite divergent pattern to the low liquid density appears. Especially, the three-dimension effect on the distribution of the particles and the free-surface appears in the divergent regime.
피치계 활성탄소섬유기반 가스센서 제조 및 유해가스 감응 특성
김민일 ( Min Il Kim ),이영석 ( Young Seak Lee ) 한국공업화학회 2014 공업화학 Vol.25 No.2
피치계 활성탄소섬유의 유해가스 감응특성을 알아보고자 피치계 활성탄소섬유와 폴리비닐알코올(PVA)을 이용하여 가스센서용 전극을 제조하였다. 제조된 가스센서용 활성탄소섬유 전극의 물리화학적 특성은 주사전자현미경(SEM) 및 비표면적 측정기(BET)를 이용하여 분석하였다. 또한, 전극의 유해가스 감응특성은 NH3, NO 및 CO2와 같은 여러 유독가스를 이용하여 확인하였다. 가스센서용 활성탄소섬유 전극의 비표면적은 바인더인 PVA에 의하여 활성탄소섬유보다 33% 감소하였지만, 전극의 기공크기분포는 PVA에 의하여 크게 영향을 받지 않았다. 가스센서용 활성탄소섬유 전극은 반도체 기반 가스센서와는 다르게 전자도약에 의해서 유해가스를 감응하였다. 본 연구에서, 활성탄소섬유 전극의 저항은 100 ppm의 NH3 유해가스에 대하여 7.5% 감소하였으며, 그 NH3 가스 감응특성이 다른 유해가스보다 뛰어남을 확인하였다. The electrode for gas sensor was prepared by using pitch-based activated carbon fibers and polyvinyl alcohol (PVA) to inves-tigate the toxic gas sensing characteristics. The physicochemical properties of activated carbon fibers electrode for gas sensor were analyzed with SEM and BET. Toxic gases sensing property of the electrode was also identified by different toxic gases such as NH3, NO and CO2. The specific surface area of activated carbon fibers electrode for gas sensor was decreased by 33% owing to PVA used as a binder compared with the activated carbon fibers. However, its pore size distribution of the ACF electrode was not greatly influenced by PVA. The activated carbon fibers electrode for gas sensor responded to toxic gases by electron hopping unlike semiconductor based gas sensors. In this study, activated carbon fibers electrode was de-creased to 7.5% in resistance for the NH3 gas of the 100 ppm concentration and its NH3 gas sensing property was confirmed the most excellent compared with other toxic gases.