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        검색결과 23

        1.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study focuses on how the partial substitution of copper by nickel nanoparticles affects the electrical and structural properties of the Bi2Ba2Ca2Cu2.9Ni0.1O10+δ, Bi2Ba2Ca2Cu2.8Ni0.2O10+δ and Bi2Ba2Ca2Cu2.6Ni0.4O10+δ compounds. Approximate values of crystallization size and crystallization percentage for the three compounds were calculated using the Scherer, modified Scherer, and Williamson-Hall methods. A great similarity was observed in the crystal size values from the Scherer method, 243.442 nm, and the Williamson-Hall method, 243.794 nm for the second sample. At the same time this sample exhibited the highest crystal size value for the three methods. In the examination of electrical properties, the sample with 0.1 partial substitution, Bi2Ba2Ca2Cu2.9Ni0.1O10+δ was determined to be the best with a critical temperature of 100 K and an energy gap of 6.57639 × 10-21 MeV. Using the SEM technique to analyze the structural morphology of the three phases, it was discovered that the size of the granular forms exceeds 25 nm. It was determined that the samples’ shapes alter when nickel concentration rises. The patterns that reveal the distribution of the crystal structure also exhibit clear homogeneity.
        4,000원
        14.
        2016.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        La1-xBaxMnO3 (x = 0.30, 0.35 and 0.40) samples have been prepared by solid-state reaction method. The X-ray diffraction (XRD) study showed that all the samples crystallized in a rhombohedral structure with an R-3c space group. Variation of the magnetization as a function of the temperature and applied magnetic field was carried out. All the samples revealed ferromagnetic to paramagnetic (FM-PM) phase transition at the Curie temperature TC ~ 342 K. The magnetic entropy change was also studied through examination of the measured magnetic isotherms M(H, T) near TC. The magnetocaloric effect was calculated in terms of the isothermal magnetic entropy change. The maximum entropy change reaches a value of 1.192 J/ kgK under a magnetic field change of 2.5T for the La0.6Ba0.4MnO3 composition. The relative cooling power (RCP) is 79.31 J/ kg for the same applied magnetic field.
        4,000원
        15.
        2016.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the effect of W substitution on the precipitation behavior of χ and σ phases in super duplex stainless steel. The χ phase was precipitated at the interface of ferrite / austenite phases and inside the ferrite phase at the initial stage of aging. With an increase in the aging time, the volume fraction of the χ phase increased, and then decreased with the transformation from the χ phase to the σ phase. The σ phase was precipitated later than the χ phase, and the volume fraction of x phase increased with the increase in the aging time. The ferrite phase was decomposed into the new austenite (γ2) and σ phases by aging treatment. The decomposition of the ferrite phase into the γ2 and σ phases was retarded by W substitution for Mo. The volume fraction of the χ phase increased and that of the σ phase decreased due to W substitution. The χ and σ phases were intermetallic compounds, which had lower nickel concentration, and higher chromium, molybdenum, and tungsten concentrations. The χ phase has higher molybdenum and tungsten concentrations than those of the σ phase. The amounts of chromium and nickel in the χ and σ phases did not change, but these phases have higher concentrations of molybdenum and tungsten due to W substitution for Mo.
        4,000원
        17.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        느타리버섯 병재배용 재료중 비트펄프를 대체하기 위해열매탈과팜이삭(PEFB)를 6, 8mm 형태의 펠렛으로 성형한 후 첨가비율을 달리하여 5개의 처리구로 나누어 느타리버섯을 재배한 결과는 다음과 같았다. 수한1호의 경우,T1 78.8g, T2 90.6g, T3 76.0g, T4 88.6g, T5 55.4g으로 대조구인 T1보다 T2, T4처리구에서 수량이 많았다.춘추계통의 김제5호의 경우, T1 111.6g, T2 139.8g, T3133.47g, T4 126.8g, T5 136.2g으로 T2, T5처리구에서수량이 많았다. 위 시험결과를 종합해볼 때, 열매탈과팜이삭(PEFB)를 비트펄프로 대체하여 느타리버섯 재배에 이용이 가능함을 확인할 수 있었다.
        4,000원
        19.
        1999.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        기계적합금법으로 Ti와 B의 혼합분말로부터 TiB2분말을 제조하였고, Zr과 Ta의 Ti 치환 효과를 조사하였다. (Ti+B)의 혼합분말을 280시간 분쇄하여 TiB2단일상을 얻었고 기계적합금화 도중 비정질상은 관찰되지 않았다. Ti의 일부를 원자반경이 Ti보다 큰 Zr으로 치환한 결과 기계적합금화에 걸리는 시간이 크게 감소한 반면에, 붕화물 생성열이 절대값이 TiB2상보다 작은 Ta로 치환하면 280시간 분쇄하여도 단일상을 형성하지 못하였다.
        4,000원
        20.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Pb(In1/2Nb1/2)O3 (PIN)세라믹스에서 Pb+2이온 대신에 Ca+2, Sr+2, Ba+2 이온을 부분적으로 치환하여 상합성 과정 및 유전특성을 조사하였다. 페로브스카이트 PIN을 얻기위한 최적조건을 도출하기위하여 하소, 치환 이온의 종류 및 그량, 소결민돌, 유전특성의 관점에서 관찰하였다. 페로브로스카이트 PIN상을 합성하기 위해서는 Ba+2이온의 치환이 가장 효과적이었다.
        4,000원
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