• 한국세라믹학회지
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• 제37권10호
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• pp.1008-1013
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• 2000

SrTi $O_3$(001) 단결정 기판 위에 졸-겔 스핀코팅으로 $SrBi_2(Ta,Nb)_2O_9$ 박막을 도포하고 그 결정화 과정을 고온 X-선 회절분석 (HTXRD)으로 추적하면서 Pt(111)/Ti/ $SiO_2$/Si 위에 성장한 박막과 비교하였다. SrTi $O_3$(001) 단결정 기판 위에 도포된 $SrBi_2Nb_2O_{9}$ 박막은 fluorite-like phase와 같은 transient phase를 거치지 않고 곧바로 순수한 $SrBi_2Nb_2O_9$ 상으로 결정화가 시작되었으며 결정화가 시작되는 온도인 ${\sim}540^{\circ}C$부터 c축 배향성장하였다. 또한 $SrB i_2(Ta,Nb)_2O_9$ 박막은 Ta/Nb 비에 관계없이 $SrTiO_3$(001) 위에서 모두 $(00{\ell})$로 배향되었으며, 코팅 횟수가 늘어나 필름의 두께가 증가함에 따라 c축 배향성은 미세한 감소를 보였다. $SrBi_2Nb_2O_9/SrTiO_3$단면을 TEM으로 관찰한 결과 $SrBi_2Nb_2O_9$은 대체로 불규칙한 크기의 다결정체로 되어 있었으나 계면 부근에서는 [001]$_{SBN}$//[001]$_{SrTi}$ $O_3$/, [100]$_{SBN}$//[100]$_{SrTi}$ $O_3$/라는 결정학적 관계를 가지며 에피탁샬 성장했음을 알 수 있었다.있었다.

• 대한화학회지
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• 제43권5호
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• pp.547-551
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• 1999

$Ca_{1.5-1.5x}Bi_xVO_4$계 화합물에 대하여 Bi 치환량(x)에 따른 결정상을 조사한 결과, 치환량이 x=0.14까지 다른 상의 생성없이 단일상으로 존재하였으나, 치환량이 0.18 이상인 경우 새로운 화합물인 $BiV_{1.025}O_{4+x}$가 함께 석출되었다. $BiV_{1.025}O_{4+x}$의 양은 x=0.18인 경우 16%, x=0.22인 경우 21%임이 확인되었다. Bi의 치환량이 0.02인 경우 구조의 변화가 거의 없었으나, 치환량이 0.06∼0.14일 때 치환량에 따른 면간거리(d)의 변화량은 0.01 mole% Bi당 (214)면은 $1.7417{\times}10^{-3}{\AA}$,(300)면은 $1.7417{\times}10^{-3}{\AA}$을 나타내었다. 단일상으로 존재하는 최대 치환량이 x=0.14인 $Ca_{1.29}Bi_{0.14}VO_4$ 조성 화합물은 합치용융조성(congruent melting composition)이 아니며, 이 조성이 용융을 시작하는 고상선 온도(solidus temperature)는 1182$^{\circ}C$임을 알 수있었다.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.228-234
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• 2012

This paper presents the algorithm of the compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it sugest simple method to solve the problem. PSIM simulation is used to validate the proposed algorithm.

• 수산해양기술연구
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• 제30권4호
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• pp.350-356
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• 1994

We have prepared superconducting Bi-Pb-Sr-Ca.Cu-O thin films by RF magnetron sputtering technique, on heated MgO(100) substrates. Sputtering was carried out in a mixture of argon and oxygen(10%) and the pressure was maintained at 5 mTorr during deposition. The substrate temperature was maintained $400^{\circ}C$ during deposition. The films sputtered were amorphous and insulating. All the films became superconducting by annealing, The films annealed at $880^{\circ}C$ for 30 minutes in air showed high-Tc phase with zero resistivity of 93K. These results indicate that the growth of the high-Tc phase is promoted by the presence of Pb at annealing temperature.

• 한국세라믹학회지
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• 제26권5호
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• pp.655-660
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• 1989

The physical properties and sinterabilities of ZrO2-Y2O3-Bi2O3 ternary system powder prepared by coprecipitation were investigated. The crystallization temperatures of ternary system were increased and the specific surface areas were decreased with increasing Bi2O3 amount as sintering agents both PSZ and FSZ. Especially, the partially stabilized zirconia showed monoclinic phase. The sinterability was increased with the amount of Bi2O3 added which caused liquid phase sintering.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.538-541
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• 2003

BSCCO superconducting thin films have been fabricated by co-deposition using IBS(Ion Beam Sputtering) method. Despite setting the composition of thin film Bi2212 or Bi2223, in both cases, Bi2201, Bi2212 and Bi2223 phase were appeared. It was confirmed the obtained field of stabilizing phase was represented in the diagonal direction of the right below end in the Arrhenius plot of temperature of the substrate and PO$_3$, and it was distributed in the rezone. The XRD peak of the generated film continuously changed according to the substrate temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.351-352
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• 2006

BSCCO thin films are fabricated by an ion beam sputtering method, and sticking coefficients of the respective elements are evaluated. The sticking coefficient of Bi element in BSCCO film formation was observed to show a unique temperature dependence; it was almost a constant value of 0.49 below about $730^{\circ}C$ and decreased linearly over about $730^{\circ}C$. In contrast, Sr and Ca, displayed no such remarkable temperature dependence. This behavior of the sticking coefficient was explained consistently on the basis of the evaporation and sublimation processes of $Bi_2O_3$. It was concluded that Bi(2212) thin film constructs from the partial melted Bi(2201) phase with the aid of the liquid phase of $Bi_2O_3$.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.63-66
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• 2003

1 km length of Bi-2223/Ag superconducting wires were fabricated by stacking, drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to Predict the sausaging and stress limit, Rolling parameters such as thickness, width and winding tension were investigated to roll the tape with uniformity. Critical current of 1 km length of superconducting tapes was measured about 50 A continuously after final sintering.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.897-900
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• 2000

Annealing dependencies of the fatigue properties of SrBi$_2$Ta$_2$$O_{9}$ thin films were observed as function of substrate temperature(400-50$0^{\circ}C$) by the rf magnetron sputtering method. With increasing annealing temperature from $600^{\circ}C$ to 85$0^{\circ}C$, flourite phase was crystalized to $650^{\circ}C$ and Bi-layered perovskite phase was crystalized above $700^{\circ}C$. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 101o switching cycles.s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.104-107
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• 2000

High quality BSCCO thin films have been fabricated by means of an ion beam sputtering at various substrate temperatures, T$\_$sub/, and ozone gas pressures, PO$_3$. The correlation diagrams of the BSCCO Phases appeared against T$\_$sub/ and PO$_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi2201 and Bi2223 phases as well as Bi2212 one come out as stable phases depending on T$\_$sub/ and PO$_3$. From these results, the thermodynamic evaluations of ΔH and ΔS which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase are performed.