• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.249-250
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• 2006

Bi-2212/Ag ROSAT용 와이어의 제작은 PIT법으로 제작된 단일 필라멘트가 사용되었다. 제작된 필라멘트를 압연하여 너비 8.6mm, 두께 2.15mm의 압연 테입을 제조한 후 4개씩 적층하여 3 부분의 마름모로 만들어 다시 내경 17.2mm의 Ag튜브에 적층하여 ROSAT 와이어를 약 150 mm로 제작하였다. 제작된 ROSAT 와이어는 산소분위기에서 약 60시간 동안 열처리 되었다. 이때 열처리 온도와 최고점에서의 유지시간에 따른 Bi-2212/Ag ROSAT 와이어의 전기적 특성을 평가 하였다. 기존의 Bi-2212/Ag 와이어에 비해 압연, 적층, 인발하여 제작된 동일한 크기의 ROSAT 와이어가 향상된 전기적 특성을 나타내었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.615-618
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• 2003

동시 성막법에 의한 저속 성장으로 Bi 2201 및 Bi 2212 박막을 제작하였다. Bi 2212의 조성이 되도록 각 원소를 공급하고 기판 온도 및 산화 가스 압력을 변화시켜 성막을 한 결과 낮은 기판 온도에서는 Bi 2201의 단상이 생성되었으며 75$0^{\circ}C$ 이상이 되면 Bi 2212 상이 생성되었다. 이 중간 온도 영역에서는 Bi 2212와 Bi 2201의 고용체가 생성되고 있음을 해석하였다. 순차 성막법에서 생성막을 평가한 결과 성막이 이루어지고 있는 박막의 가장 표면은 목적 조성으로부터 벗어난 상태에 있으며 결정 구조의 전하 중성 조건을 예상한 곳의 표면은 불안정하다는 것을 알 수 있었다. Bi 2201 상이 생성된 막에서도 순차 성막 과정에 의한 막 생성이라기보다는 오히려 박막 내부에서의 원자 확산 과정에 의해 생성된 것으로 생각된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.91-92
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• 2006

The important merit of Bi-2212/Ag wire is to apply cable as round wire state. Bi-2212 high Tc superconducting wires were fabricated in order to apply Rutherford cable near the future. Various Ag ratio from 0.22 to 0.42 of Ag tubes for PID (powder-In-Tube) process were used to investigate the workability and to prevent breakage of filaments during drawing. In order to find proper heat treatment condition, we investigated micro-structure of Bi-2212/Ag wires by using differential thermal analysis, XRD and SEM. The effect of atmosphere on the peritectic decomposition temperature of precursor was investigated. The shape of grain was observed by SEM to investigate Bi-2212 phase formation in filaments. The higher of Ag ratio of mono filament had the higher critical current density, Jc. The wire with 0.42 of Ag ratio showed 7,886 A/cm2 of Jc at 77K.

• Progress in Superconductivity
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• 제9권1호
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• pp.18-22
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• 2007

For interlayer tunneling spectroscopy using a small stack of $Bi_2Sr_2CaCu_2O_{8+x}$ (Bi-2212) intrinsic junctions in a high-bias range, large self-heating takes place due to the poor thermal conductivity of Bi-2212. In this study, we numerically estimate the self-heating around a Bi-2212 sample stack for I-V or dI/dV-V measurements. Our results show that the temperature discrepancy between the Bi-2212 sample stack and top Au electrodes due to bias-induced self-heating is small enough along the c-axis direction of Bi-2212. On the other hand, the lateral temperature discrepancy between the sample stack and the Bi-2212 on-chip thermometer stack can be as large as ${\sim}20\;K$ for the highest bias required to observe the pseudogap hump structure. We thus suggest a new in-situ ac thermometry, employing the Au current-bias electrode itself deposited on top of the sample stack as the resistive thermometer layer, which is supposed to allow safe temperature measurements for the interlayer tunneling spectroscopy.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.282-284
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• 2007

The superconductor characteristics of BSCCO spray films by Heat treatment was studied. $Bi_2Sr_2CaCu_2O_x$(Bi-2212) is high-Tc superconductor(HTS) coatings have been prepared by Heat treatment. Where high current carrying capabilities are required and therefore thick film and bulk material are called for, the Bi2Sr2Ca1Cu2O8-d(Bi-2212)compound has evoleved as one of the most promising. and the Bi-2212 HTS coating layer is synthesized through the peritectic reaction between Sr-Ca-Cu oxide coating layer and Bi-Cu oxide coating layer by partial melting process. The superconducting characteristics depends on the spray distance which was related to the spray particle melt. The Bi-2212 HTS layer consists of the whisker growth and secondary phase in 2212 layer were observed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.536-539
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• 2007

BSCCO 박막은 다양한 기판온도와 산화 가스압에 변화에서 증발법에 의해 제작되었다. 박막조성을 Bi2212 또는 Bi2223으로 설정했음에도 불구하고, 어느 경우나 Bi2201, Bi2212 및 Bi2223상이 생성되었다. 이들 안정상의 생성 영역은 기판 온도-산화 가스압의 Arrhenius 플롯에서 우측 하단 방향으로 경사진 직선으로 표시되며 매우 좁은 영역에 분포되어 있다. 생성막의 XRD 피크는 기판 온도에 따라 연속적으로 변화했다. 이는 Bi2201, Bi2212, Bi2223의 각상이 결정 구조 내에 혼합되어 있는 혼합 결정계의 존재를 나타내고 있으며, 각 상의 단상막은 매우 좁은 온도, 가스압 범위에서만 생성되었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.104-105
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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.ormed.i2212 or Bi2223 phase are performed.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.296-299
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• 1999

Bi$_2Sr_2CaCu_2O$(Bi-2212) thick films were fabricated on Y2l1 substrate by screen printing method. And the samples were annealed in various atmospheres, respectively. Though samples had many voids, the sample annealed in N$_2$ ; O$_2$ = 1:0 atmosphere and the sample in N$_2$ : O$_2$ = 0:1 showed some Bi 2212 low phase in comparison to other samples. The thickness of Bi-2212 on Y2ll substrates was about 20 ${\mu}$m.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.66-70
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• 2003

Transient magnetic diffusion process in a melt-cast Bi2Sr2CaCu20X(Bi-2212) tube was studied by experimental and numerical analyses. The transient diffusion partial differential equation is transformed into an ordinary differential equation by integral method. The penetration depth of magnetic field into a superconducting tube is obtained by solving the differential equation numerically. The results show that the penetration depth as a function of time which is somewhat different from the results by Bean's critical state model. The reason of the difference between the present results and that of Bean's model is discussed and compared in this paper. This experiment measure the magnetic flux density in the supercondutor after supply direct-current of Bi-2212 rounded by copper coil. This study was discussed of valid of a previous numerical solution which is compared by the penetrate time and the magnetic flux density difference of between the present results and the numerical solution.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.108-111
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• 2000

Bi2212 and Bi2223 thin films are fabricated by ion beam sputtering method. Three phases of Bi2201, Bi2212 and Bi2223 appear as stable ones in spite of the condition for thin film fabrication of Bi2212 and bi2223 compositions, depending on substrate temperature(T$\sub$sub/) and ozone pressure (PO$_3$). It is found out that these phases show similar T$\sub$sub/ and PO$_3$dependence, and that the stable regions of these phases are limited within very narrow temperature.