• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.297.2-297.2
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• 2007

• 한국초전도ㆍ저온공학회논문지
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• 제10권2호
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• pp.20-23
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• 2008

[ $La_2Zr_2O_7$] (LZO) buffer layers were deposited on biaxially textured Ni-W substrates by chemical solution deposition method (CSD). In this study, the effect of $B_2O_3$ addition on texture and surface roughness of LZO films was investigated. The alkoxide-based precursor solution was employed to synthesize the precursor solution of LZO and the solution was coated on biaxially textured Ni-W substrates and subsequently annealed at $900^{\circ}C$ for crystallization. The pure LZO film without $B_2O_3$ addition showed a (222) reflection in the X-ray diffraction (XRD) profile. The intensity of (222) reflection was enhanced and more rough surface was obtained after further repetition of coating. Contrary to this, the LZO film prepared by $B_2O_3$ added precursor solution shows well-developed (400) reflection peak in the XRD profile and excellent biaxial texture (${\Delta}{\theta}=4.3^{\circ}$, ${\Delta}{\phi}=6.8^{\circ}$). The surface roughness of LZO films were also improved by addition of $B_2O_3$ even after multicoating ($R_{rms}{\sim}3.1nm$). It was shown that the LZO film with smooth surface and biaxial texture was grown on the biaxially textured Ni-W substrates with addition of $B_2O_3$ in the precursor solution.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2002년도 High Temperature Superconductivity Vol.XII
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• pp.72-72
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• 2002

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.95-98
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• 1999

The crystalline alignment of Ni substrates textured by RABiTS have a probability distribution in the surface plane. This makes it difficult to obtain a high quality of textures over all the range of a long Ni tape. In order to improve the textures of Ni tape, we have investigated a new method of texturing. We obtained non-cube textured Ni tapes by rolling and annealing a high purity Ni. In these tapes, the [001]-axes were tilted around the rolling direction, and the [100]-axes were parallel to the rolling direction. The average grain size was several cm$^2$. We deposited buffer layer (CeO$^2$/YSZ/CeO$^2$) and YBCO on those tapes. We found out that a YBCO film with grows normal with respect to the surface and this feature is independent of the tilting angles of the Ni [001]-axes.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.339-339
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• 2002

In the RABiTS approach to coated conductor development, successful (both economic and technological) depends on the refinement and optimization of each of three important components: the metal tape substrate, the buffer layer(s), and the HTS layer. Here we will report on the ORNL approach and progress in each of these areas. - Most applications will require metal tapes with low magnetic hysteresis, mechanical strength, and excellent crystalline texture. Some of these requirements are competing. We report on progress in obtaining a good combination of these characteristics on metal alloys of Ni-Cr and Ni-W. - The deposition of appropriate buffer layers is a crucial step. Recently, base research has shown that the presence of a stable sulfur superstructure present on the metal surface is needed for the nucleation and epitaxial growth of vapor-deposited seed buffer layers such as YSZ, CeO$_2$ and SrTiO$_3$. We report on the details and control of this superstructure for nickel tapes, as well as recent results for Cu and Ni-13%Cr. - Processes for deposition of the HTS coating must economically provide large values of the figure-of-merit for conductors, current x length. At ORNL, we have devoted efforts to a precursor/post-annealing approach to YBCO coatings, for which the deposition and reaction steps are separate. We describe motivation for and progress toward developing this approach. - Finally, we address some issues for the implementation of coated conductors in real applications, including the need for texture control and electrical stabilization of the HTS coating.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1590-1592
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• 1999

We have fabricated good quality superconducting $YBa_2Cu_3O_{7-{\delta}}$ thin films on Hastelloy(Ni-Cr-Mo alloys) with $CeO_2$ buffer layers by in-situ pulsed laser deposition in a multi-target processing chamber. Using one of electrical properties of YBCO superconducting which the resistance approaches to zero dramatically on transition temperature, we have researched to make power transmission line, we have deposited YBCO thin film on flexible metallic substrate. However, it is difficult to make films on flexible metallic substrates due to both interdiffusion problem between metallic substrate and superconducting layer and non-crystallization of YBCO on amorphous substrate. From early research, two ways-using textured metallic substrate and buffer layer-were proposed to overcome theses difficulties. We have chosen $CeO_2$ as a buffer layer which has cubic structure of $5.41{\AA}$ lattice parameter and only 0.2% of lattice mismatch with $3.82{\AA}$ of a-axis lattice parameter of YBCO on (110) direction of $CeO_2$. In order to enhance the crystallization of YBCO films on metallic substrates we deposited $CeO_2$ buffer layers at varying temperature $700^{\circ}C$ to $800^{\circ}C$ and $O_2$ pressure. By X-ray diffraction, we found that each domination of (200) and (111) orientations were strongly relied upon the deposition temperature in $CeO_2$ layer and the change of the domination of orientation affects the crystallization of YBCO upper layer.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.170.2-170
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• 2003

• 한국초전도ㆍ저온공학회논문지
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• 제5권3호
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• pp.11-14
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• 2003

The detailed conditions of dc-sputtering for depositions of yttria-stabilized ZrO$_2$ (YSZ) films were investigated, while the films were grown on the CeO$_2$ template layers on biaxially textured Ni-tapes. The window of oxygen pressures for proper growth of YSZ films, which was dependent on sputtering powers, was determined by sufficient oxidations of the YSZ films and the de-oxidation of the target surface, which was required for rapid sputtering. The window turned out to be fairly wide under certain values of argon pressure. When the sputtering power was raised, the deposition rate increased without narrowing the window. The fabricated YSZ films showed good texture qualities and surface morphologies.

• 한국결정학회지
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• 제14권2호
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• pp.51-55
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• 2003

YBa₂CU₃O/sub 7-8/(YBCO) coated conductor의 완충층 구조를 개선하기 위하여 2축배향된 Ni-3 wt%W 합금 기판위에 단일 완충층으로 SrTiO₃(STO) 박막을 증착하였다. YBCO와 STO 박막은 펄스레이저 증착법으로 성장시켰다. STO 박막의 표면은 증착온도에 따라 다른 미세조직을 보여 주었고, XRD 분석에서는 STO와 YBCO 박막이 금속기판의 배향성을 가지면서 성장되었음을 알 수 있었다. 액체질소 온도에서 1.2 MA/㎠의 임계전류밀도와 86 K의 임계온도를 가지는 짧은 길이의 coated conductor를 STO 단일완충층을 이용하여 제조하였다.

• 전기화학회지
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• 제7권4호
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• pp.206-210
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• 2004

금속산화물 $(TiO_2,\;RuO_2,\;PbO_2,\;Ni(OH)_2)$과 Prussian blue (PB)를 각각 탄소반죽에 혼합한 후 스크린 프린팅 기법으로 6종의 탄소반죽 전극들을 제작하였다. 제작된 탄소반죽 전극들로 전자혀 시스템을 제작하여 다양한 음료수와 식품에 대한 감응을 0.1M carbonate buffer, pH 9.6완충 용액에 묽힌 후 대시간전류법의 방법으로 측정하였다 얻어진 자료를 주성분 분석법 (principal component analysis; PCA)으로 처리한 후 식음료의 맛을 평가할 수 있도록 2차원 좌표계에 표시하였으며, 그 결과 본 실험에서 제작한 시스템 및 분석법은 다양한 식음료의 종류를 뚜렷이 구분해 낼 수 있음을 확인하였다.