• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
• /
• pp.30-30
• /
• 2003

• 한국전기전자재료학회논문지
• /
• 제13권9호
• /
• pp.801-804
• /
• 2000

High-temperature superconductor of Bi-2212 system was fabricated by CFP(Centrifugal Forming Process). To make a uniform specimen slurry was prepared in the ratio of 7:3(powder : binder) and ball milled for 24 hours. Milled slurry was charged into a rotating mold with 450 rpm and dried at room temperature. Then the specimen was performed binder burn-out at 35$0^{\circ}C$ and heated for partial melting to 86$0^{\circ}C$. XRD analysis of most specimens were shown 2212 phase and observed a local plate shped microstructure with a well aligned c-axis direction from SEM images. Measured T$_{c}$(Critical temperature) was about 64 K.K.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.189-192
• /
• 2000

High-temperature superconductor of Bi-2212 system was fabricated by CFP(centrifugal forming process). To make a uniform specimen slurry was prepared in the ratio of 7:3(powder:binder) and ball milled for 24 hours. Milled slurry was charged into a rotating mold with 450 rpm and dried at room temperature. Then the specimen was performed binder burn-out at 35$0^{\circ}C$ and heated for partial melting to 86$0^{\circ}C$. XRD analysis of most specimens were shown 2212 phase and observed a local plate shaped microstructure with a well aligned c-axis direction from SEM images. T$_{c}$(Critical temperature) of Bi-2212 was 64K.K.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2008년도 Asian Magnetics Conference
• /
• pp.107.1-107.1
• /
• 2008

• 한국자기학회지
• /
• 제2권3호
• /
• pp.228-232
• /
• 1992

고온초전도체 $Y_1Ba_2Cu_3O_{7-y}$의 grain을 높은 자기장에서 정렬시켜 여러가지 자기적 특성을 조사하였다. Grain이 정렬된 초전도체는 단결정과 같이 Cu-O layer에 수직, 수평 방향에 대해 자기이방성을 가진다. 2~77 K의 온도영역에서 측정한 lower critical field$(H_{c1})$은 온도가 증가하면서 선형적으로 감소하였는데, Cu-O layer에 대하여 외부 자기장이 수직인 경우가 더욱 급격히 감소하였다. 온도변화에 따른 자율화$(4{\pi}\;X)$의 측정으로부터 극저온의 자화율이 -1에 가까운 값을 가진다는 것을 알 수 있었다. 또한 이 자화 곡선을 London의 공식과 two-fluid model을 이용해 최소자승법으로 fitting하여 절대 영도에서 침투깊이$({\lambda}_0)$를 구하였다. 또한 2 K에서 외부 자기장에 따른 자화곡선을 측정하였으며, Bean의 critical state model을 이용한 임계전류밀도$(J_c)$의 계산으로부터 grain내부는 단결정 수준의 높은 $(J_c)$를 가지고 있음을 알 수 있었다.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
• /
• pp.218-221
• /
• 1999

Magnetization measurements have been carried out on grain aligned Hg-1223 with the applied field parallel to the c-axis. The temperature dependence of the lower critical field H$_{cl}$(T) was determined by considering the effect of the surface barrier on the magnetization. H$_{cl}$(T) have been determined .from magnetic hysteresis loops within the framework of the modified Kim-Anderson critical-state model, where the surface barrier and the lower critical field are explicitly considered. At high temperature, H$_{cl}$(T) is identified as H$_p$(T). This results are agreed with the theory of Bean-Livinston surface barriers.

• Progress in Superconductivity
• /
• 제13권1호
• /
• pp.40-46
• /
• 2011

A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. A 10 kWh class flywheel energy storage system (FESS) has been developed to evaluate the feasibility of a 35 kWh class SFES with a flywheel $I_p/I_t$ ratio larger than 1. The 10 kWh class FESS is composed of a main frame, a composite flywheel, active magnetic dampers (AMDs), a permanent magnet bearing, and a motor/generator. The flywheel of the FESS rotates at a very high speed to store energy, while being levitated by a permanent magnetic bearing and a pair of thrust AMDs. The 10 kWh class flywheel is mainly composed of a composite rotor assembly, where most of the energy is stored, two radial and two thrust AMD rotors, which dissipate vibration at critical speeds, a permanent magnet rotor, which supports most of the flywheel weight, a motor rotor, which spins the flywheel, and a central hollow shaft, where the parts are assembled and aligned to. The stators of each of the main components are assembled on to housings, which are assembled and aligned to the main frame. Many factors have been considered while designing each part of the flywheel, stator and frame. In this study, a 10 kWh class flywheel energy storage system has been designed and constructed for test operation.