• 제목/요약/키워드: MOD method

검색결과 235건 처리시간 0.022초

Eu 첨가에 따른 PZT 박막의 유전 특성 (Dielectric properties of Eu-doped PZT thin films)

  • 손영훈;김경태;김창일;장의구;이병기
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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    • pp.155-158
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    • 2002
  • Eu-doped lead zirconium titanate $Pb_{1.1}(Zr_{0.3}Ti_{0.7})O_{3}$ thin films on the Pt/Ti/$SiO_2$/Si substrates prepared by a metalorganic decomposition (MOD) method. The effect on the structural and electrical properties of the films measured according to Eu content. Eu-doping altered significantly the dielectric and ferroelectric properties. The remanent polarization and coercive field decreased with increasing the concentration of Eu content. The dielectric constant and dielectric loss of the film decreased with increasing Eu contents. The 3 mol% of Eu-doped PZT thin film showed large remanent polarization and the fatigue characteristic of the film did not change up to $10^9$ switching cycles.

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FRAM 응용을 위한 BLT박막의 제작 및 특성 (A Fabrication and ferroelectric properties of BLT Thin Films for FRAM)

  • 김경태;권지운;심일운;김창일
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.565-568
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    • 2001
  • We have fabricated $Bi_{3.25}$$La_{0.75}$ti$_3$O$_{12}$ (BLT) thin(200nm) films on the Pt/Ti/SiO$_2$/Si substrates using a MOD(Metalorganic decomposition) method with annealing temperature from 55$0^{\circ}C$ to 75$0^{\circ}C$. The structural properties of the films examined by x-ray diffraction. The layered-perovskite phase obtained above $600^{\circ}C$. Scanning electron micrographs showed uniform surface composed of rodlike grains. The grain size increased with increasing annealing temperature. The BLT thin films showed little polarization fatigue test up to 3.5x10$^{9}$ bipolar cycling at a 5V and 100kHz.kHz.

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수열합성법에 의한 정렬된 ZnO 나노로드 구조의 합성 (Synthesis of Aligned ZnO Nanorod Arrays via Hydrothermal Route)

  • 구진희;이병우
    • 한국표면공학회지
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    • 제49권5호
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    • pp.472-476
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    • 2016
  • The nano-array of the vertically aligned rod-like particles grown on ZnO coated glass-substrates was obtained via hydrothermal process. ZnO thin film coatings were prepared on the glass substrates using a MOD (metallorganic deposition) dip-coating method with zinc chloride dihydrate as starting material and 2-ethylhexanol as solvent. ZnO nanorods were synthesized on the seeded substrates by hydrothermal method at $80^{\circ}C$ using zinc-nitrate hexahydrate as a Zn source and sodium hydroxide as a mineralizer. Under the hydrothermal condition, the rod-like nanocrystals were easily attaching on the already ZnO seeded (coated) glass surface. It has been shown that the hydrothermal synthesis parameters are key factors in the nucleation and growth of ZnO crystallites. By controlling of hydrothermal parameters, the ZnO particulate morphology could be easily tailored. Rod-shaped ZnO arrays on the glass substrates consisted of elongated crystals having 6-fold symmetry were predominantly developed at high Zn precursor concentration in the pH range 7~11.

Metal-Organic Decomposition법에 의한 강유전성 $YMnO_3$ 박막의 제조 및 특성 (Preparation of Ferroelectric $YMnO_3$ Thin Films by Metal-Organic Decomposition Process and their Characterization)

  • 김제헌;강승구;김응수;김유택;심광보
    • 한국세라믹학회지
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    • 제37권7호
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    • pp.665-672
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    • 2000
  • The ferroelectric YMnO3 thin films were prepared by MOD(metal-organic decomposition) method with Y- and Mn-acetylacetonate as starting materials. Thin films were grown on various substrates by spin-coating technique. The crystalline phases of the thin films were identified by X-ray diffractometer as a function of heat-treatment temperature, pH of coating solution and substrate. In addition, the effect of Mn/Y molar ratio(0.8~1.2) on the formation of hexagonal-YMnO3 phase was investigated. In forming highly c-axisoriented hexagonal-YMnO3 single phase, the Pt coated Si substrate was more effective than the bare Si substrate, and the optimum heat-treatment condition was at 82$0^{\circ}C$ for 30 min. Higher Mn/Y molar ratio within 0.8~1.2 and pH of YMnO3 precursor solution within 0.5~2.5 favored formation of ferroelectric hexagonal phase rather than orthorhombic phase. Leakage current density of the hexagonal-YMnO3 thin film formed on Pt(111)/TiO2/SiO2/Si substrate was low enough as 0.4~4.0$\times$10-8(A/$\textrm{cm}^2$) at 5 V and its remanent polarization(Pr), calculated from the P-E hysteresis loop, was 3 nC/$\textrm{cm}^2$.

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MOD법으로 제작한 $Bi_{3.25}La_{0.75}Ti_3O_{12}/LaNiO_3$ 박막의 강유전 특성에 관한 연구 (Ferroelectric properties of $Bi_{3.25}La_{0.75}Ti_3O_{12}/LaNiO_3$ thin films prepared by metalorganic decomposition method)

  • 김경태;김창일;김태형;이철인
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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    • pp.352-355
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    • 2003
  • [ $Bi_{3.25}La_{0.75}Ti_3O_{12}$ ] (BLT) thin films were prepared by using metal organic decomposition method onto the LaNiO3 (LNO) bottom electrode. Both the structure and morphology of the films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). Even at low temperatures ranging from 450 to $650^{\circ}C$, the BLT thin films were successfully deposited on LNO bottom electrode and exhibited (117) orientation. The BLT thin films annealed as low as $600^{\circ}C$ showed excellent ferroelectricity, higher remanent polarization and no significant degradation of switching charge at least up to $5{\times}10^9$ switching cycles at a frequency of 100 kHz and 5 V. For the annealing temperature of $600^{\circ}C$, the remanent polarization $P_r$ and coercive field were $23.5\;{\mu}C/cm^2$ and 120 kV/cm, respectively.

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개선된 자동정리증명 기법에 기초한 유한체상의 디지털논리시스템 구성 (Construction of the Digital Logic Systems based on the Improved Automatic Theorem Proving Techniques over Finite Fields)

  • 박춘명
    • 한국정보통신학회논문지
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    • 제10권10호
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    • pp.1773-1778
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    • 2006
  • 본 논문에서는 개선된 자동정리증명 기법에 기초하여 유한체상의 디지털논리 시스템을 구성하는 방법을 제안하였다. 제안한 방법은 먼저 유한체상의 중요한 학적 성질을 논의하였고 자동정리증명기법의 개념과 기본 성질을 서술하였다. 그리고 개선된 자동정리증명기법을 적용하기 위해 몇 가지 정의를 하였으며 이를 근간으로 디지털논리 시스템의 Building Block을 제안하였다. 또한, 디지털논리 시스템을 구성하기 위한 중요한 관계를 정의하였으며 최종 유한체상의 디지털논리시스템을 개선된 자동정리 증명 기법에 의해 구성하였다.

가변길이 분할 기법을 적용한 모듈러 지수연산법 (Modular Exponentiation Using a Variable-Length Partition Method)

  • 이상운
    • 한국인터넷방송통신학회논문지
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    • 제16권2호
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    • pp.41-47
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    • 2016
  • 암호학의 암호 생성과 해독의 곱셈 횟수는 대부분 $a^b$(mod m) 모듈러 지수연산의 효율적 구현여부로 결정된다. 표준 모듈러 지수연산법으로는 1-ary법인 이진법이 있으며, n-ary($2{\leq}n{\leq}6$)법이 많이 적용되고 있다. n-ary($1{\leq}n{\leq}6$)법은 $b=b_kb_{k-1}{\cdots}b_1b_{0(2)}$에 대해 R-L 방향으로 n비트로 고정된 분할을 하고, n회 제곱과 비트값 곱셈을 수행하는 제곱-곱셉법이다. 본 논문에서는 $b_{k-1}{\cdots}b_1b_{0(2)}$에 대해 L-R 방향으로 가변길이로 분할하는 방법을 적용한다. 또한, 개변길이의 제곱과 곱셈 또는 나눗셈을 적용한다. 제안된 가변길이 분할법은 고정길이 분할법인 n-ary법에 비해 곱셈 수행횟수를 감소시킬 수 있었다.

An Application of Realistic Evaluation Methodology for Large Break LOCA of Westinghouse 3 Loop Plant

  • Choi, Han-Rim;Hwang, Tae-Suk;Chung, Bub-Dong;Jun, Hwang-Yong;Lee, Chang-Sub
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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    • pp.513-518
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    • 1996
  • This report presents a demonstration of application of realistic evaluation methodology to a posturated cold leg large break LOCA in a Westinghouse three-loop pressurized water reactor with 17$\times$17 fuel. The new method of this analysis can be divided into three distinct step: 1) Best Estimate Code Validation and Uncertainty Quantification 2) Realistic LOCA Calculation 3) Limiting Value LOCA Calculation and Uncertainty Combination RELAP5/MOD3/K [1], which was improved from RELAP5/MOD3.1, and CONTEMPT4/MOD5 code were used as a best estimate thermal-hydraulic model for realistic LOCA calculation. The code uncertainties which will be determined in step 1) were quantified already in previous study [2], and thus the step 2) and 3) for plant application were presented in this paper. The application uncertainty parameters are divided into two categories, i.e. plant system parameters and fuel statistical parameters. Single parameter sensitivity calculations were performed to select system parameters which would be set at their limiting value in Limiting Value Approach (LVA) calculation. Single run of LVA calculation generated 27 PCT data according to the various combinations of fuel parameters and these data provided input to response surface generation. The probability distribution function was generated from Monte Carlo sampling of a response surface and the upper 95$^{th}$ percentile PCT was determined. Break spectrum analysis was also made to determine the critical break size. The results show that sufficient LOCA margin can be obtained for the demonstration NPP.

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CeO2 완충층의 결정성장 특성 및 금속 유기물 증착법으로 제조된 초전도 YBCO층에 미치는 영향 (Texture Development of CeO2 Buffer Layer and its Effect on Superconducting MOD-YBCO Films)

  • 정국채;김영국
    • 대한금속재료학회지
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    • 제47권10호
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    • pp.681-685
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    • 2009
  • $CeO_2$ buffer layers have been deposited on YSZ single crystal substrates via a radio-frequency sputtering method. We focused on the texture development of $CeO_2$ with out-of-plane alignment and its effects on a superconducting YBCO layer, which was deposited by metal organic deposition. $CeO_2$ layers were grown epitaxially on single crystal YSZ substrates and subsequent YBCO layers were also grown epitaxially from $CeO_2$ layers. It was observed that the intensity of $CeO_2$(200) decreased with deposition temperature. ${\theta}-2{\theta}$ scan FWHM values of $CeO_2$(200) were inversely proportional to the peak intensities of $CeO_2$(200). The sample with the lowest $CeO_2$(200) intensity and poor out-of-plane alignment showed a strong reaction with the MOD-YBCO layer resulting in a thicker $BaCeO_3$ layer. The texture and superconducting property of the YBCO layer were affected indirectly by the formation of a $BaCeO_3$ layer at the interface between the $CeO_2$ and YBCO layers.