• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.482-485
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• 2002

We synthesize a (Y,Sm)BCO(its composition is (Y/Sm123+0.4Y/Sm211)+1wt%CeO$_2$) powders using polymeric complex method. (Y,Sm)BCO powders are prepared as heated at 970$^{\circ}C$. For measurement of this characterization, We measure XRD and SEM. We use TSMG method for fabricatlon of (Y,Sm)BCO single crystal. The manufactured VBCO single crystal is measured by a magnetic distribution device using 0.5 Tesla magnet. As the result of this measurement, we find that a trapped magnet fields are 550 Gauss.

• 한국결정성장학회지
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• 제14권2호
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• pp.68-72
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• 2004

Sm 원소가 첨가된 $(Sm/Y)_{1.8}Ba_{2.4}Cu_{3.4}O_{7-x}$[이하 (Sm/Y)1.8] 고온초전도체를 국부용융성장법을 이용해 대기 중에서 용융성장실험을 하였다. 초기 (Sm/Y)1.8 초전도체 시편은 rubber 몰드를 이용해 냉간정수압성형(CIP) 과정을 거쳐 길이 방향 원통형상으로 제조되었다. 이렇게 얻어진 (Sm/Y)1.8 초전도체는 용융온도 및 성장속도에 따라 광학현미경, TEM그리고 SQUID magnetometer를 이용해 미세구조 및 초전도특성을 평가하였다. 이 결과 (Sm/Y)1.8 초전도체의 최적의 용융온도 및 성장속도는 $1085^{\circ}C$에서 3.5mm/hr로 나타났다. 특히 일방향으로 용융성장된 (Sm/Y)1.8 초전도체의 광학현미경 및 TEM에 의하 미세구조 관측 결과, 초전도상인 (Sm/Y)123 matrix내에 비초전도상인 (Sm/Y)211 inclusions이 균질하게 분포되어 있는 것이 관측되었다. 초전도특성을 평가한 결과 용융성장된 (Sm/Y)1.8초전도체는 90K에서 임계온도가 시작되어 77K이상의 온도에서 포화되는 특성을 보였다.

• 한국전기전자재료학회논문지
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• 제17권2호
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• pp.178-183
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• 2004

PBT thin film was known to be a representative for the FeRAM devices because of its good ferroelectric proporties and the ease in fabricating the thin film. However, there have been several problems such as polarization fatigue and leakage current in memory devices with a PZT thin film. In this study, Sm-dolled PZT thin films were fabricated by the so1-gel method, and their ferroelectric and dielectric proportrics were compared as a function of Sm content. We investigated the effect of the Sm dopant on structural and electrical properties of PZT film. Sm-doped PZT thin films on the Pt/Ti/SiO$_2$/Si substrates have been prepared by a sol-gel method. The remanent polarization and coercive field decreased with increasing the concentration of Sm. The dielectric constant and dielectric loss decreased with Increasing Sm content. Sm-doped PZT thin films showed improved fatigue characteristics compared to the undoped PZT thin film.

• 한국재료학회지
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• 제24권7호
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• pp.339-343
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• 2014

$CaWO_4:Sm_x$(x = 0, 0.5, 1.0, 1.5, 2.0 mol%) white phosphors with different concentrations of $Sm^{3+}$ ions were synthesized using the hydrothermal method. The crystal structure, surface, and optical properties of the $CaWO_4:Sm_x$ phosphors were investigated using X-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM), photoluminescence(PL) and photoluminescence excitation(PLE). From the XRD results, the crystal structure of the $CaWO_4:Sm$ phosphors was found to be tetragonal. The $CaWO_4:Sm$ phosphors became more cohesive with increasing $Sm^{3+}$-ion concentration. The photoluminescence excitation(PLE) peak of the phosphors, at around 250 nm, was ascribed to the transition from the 1A1 ground-state to the high-vibration level of 1T2 in the $WO{_4}^{2-}$ complex. The maximum emission spectra of the phosphors were observed when the $Sm^{3+}$ concentration was 0.5 mol%. The luminescence intensity of the $CaWO_4$ phosphors was decreased for $Sm^{3+}$ concentrations greater than 0.5 mol%.

• 분석과학
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• 제14권4호
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• pp.291-299
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• 2001

사용후핵연료내 핵분열생성물중 Sm 동위원소 정량을 위한 분리 및 정제에 관한 연구를 수행하였다. 일차적으로 핵분열생성물 대신 여러 비방사성 금속이온(Cs, Ba, Gd, Eu, Sm 및 Nd)들로 구성된 모의용액을 시료로 사용하였다. Sm은 AG $1{\times}8$ 음이온교환수지관에서 1 M $HNO_3$/90% MeOH 용액으로 세척 후 0.5 M $HNO_3$/80% MeOH 용액으로 용리하였다. 용출액에 함유되어 있는 미량의 Ba을 제거하기 위하여 0.2 M alpha-hydroxyisobutyric acid 용액(pH 4.5-4.6)으로 전처리한 AG $50W{\times}8$ 양이온교환수지관에서 정제하였으며, 순수한 Sm을 90% 이상 분리, 회수할 수 있었다. 실제 PWR 사용후핵연료에 함유되어 있는 Sm의 분리 및 정제에 적용하여 용출액을 질량분석한 결과 Gd, Eu, Pm, Nd 및 BaO에 의한 동중원소 영향이 나타나지 않았다. $^{154}Sm$ 스파이크를 이용한 동위원소희석 질량분석법으로 사용후핵연료 중의 Sm 및 각각의 성분 동위원소($^{147}Sm$, $^{148}Sm$, $^{149}Sm$, $^{150}Sm$, $^{151}Sm$, $^{152}Sm$ and $^{154}Sm$)들을 정량하였다.

• 한국분말재료학회지
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• 제20권1호
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• pp.13-18
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• 2013

In the present study, we systematically investigated the effect of Mn addition on nitrogenation behavior and magnetic properties of Sm-Fe powders produced by reduction-diffusion process. Alloy powders with only $Sm_2(Fe,Mn)_{17}$ single phase were successfully produced by the reduction-diffusion process. The coercivity of $Sm_2(Fe,Mn)_{17}$ powder rapidly increased during nitrogenation and reached the maximum of 637 Oe after 16 hours. After further nitrogenation, it decreased. In contrast, the coercivity of $Sm_2Fe_{17}$ powder gradually increased during nitrogenation for 24 hours. The coercivity of $Sm_2(Fe,Mn)_{17}$ powder was higher than that of $Sm_2Fe_{17}$ powder at the same condition of nitrogenation. It was considered that the Mn addition facilitates the nitrogenation of $Sm_2Fe_{17}$ powder and enhances the coercivity.

• 한국전기전자재료학회논문지
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• 제21권11호
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• pp.1019-1023
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• 2008

Photoluminescence properties of $SrTiO_3$:Sm red phosphors synthesized by solid state reaction method were studied under 254 nm excitation. Emission bands at 576 nm and 616 nm in heavily $Sm^{3+}$ ion doped $SrTiO_3$:Sm phosphors were observed, which were attributed to $^4G_{5/2}\rightarrow{^6}H_{5/2}$ and $^4G_{5/2}\rightarrow{^6}H_{7/2}$ transition of $Sm^{3+}$, respectively. The $Sm^{3+}$ ion concentration exhibiting the maximum emission intensity in the $SrTiO_3$:Sm was 30 mol%. The luminescence caused by $Sm^{3+}$ in the $SrTiO_3$:Sm phosphors was interpreted by the energy transfer between $Sm^{3+}$ ions.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.1100-1108
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• 2017

A thermal-hydraulic system code is an essential tool for the design and safety analysis of a nuclear power plant, and its accuracy quantification is very important for the code assessment and applications. The fast Fourier transform-based method (FFTBM) by signal mirroring (FFTBM-SM) has been used to quantify the accuracy of a system code by using a comparison of the experimental data and the calculated results. The method is an improved version of the FFTBM, and it is known that the FFTBM-SM judges the code accuracy in a more consistent and unbiased way. However, in some applications, unrealistic results have been obtained. In this study, it was found that accuracy quantification by FFTBM-SM is dependent on the frequency spectrum of the fast Fourier transform of experimental and error signals. The primary objective of this study is to reduce the frequency dependency of FFTBM-SM evaluation. For this, it was proposed to reduce the cut off frequency, which was introduced to cut off spurious contributions, in FFTBM-SM. A method to determine an appropriate cut off frequency was also proposed. The FFTBM-SM with the modified cut off frequency showed a significant improvement of the accuracy quantification.

• 대한금속재료학회지
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• 제48권9호
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• pp.842-846
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• 2010

In the present study, the reduction-diffusion method was employed to produce Sm-Fe alloy powder. It was confirmed that the amount of unreacted ${\alpha}-Fe$ in $Sm_2Fe_{17}$ matrix gradually decreased as the percentage of $Sm_2O_3$ increased. $Sm_2Fe_{17}$ single-phase powder was produced by the reduction-diffusion method with 40% excess $Sm_2O_3$. The Ca and Oxygen contents of the powder were approximately 300 ppm and 1600 ppm, respectively, after washing and acid treatment. By a subsequent nitrogenation, $Sm_2Fe_{17}N_x$ magnetic powders were produced. The coercivity of the powder increased with decreasing of the particle size by ball milling, and the highest coercivity of 2850 Oe was obtained after milling for 10 hours.

• 암석학회지
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• 제21권4호
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• pp.431-439
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• 2012

원소의 고순도분리는 동위원소계 연구의 기초가 된다. 이 기술보고에서는 Sm-Nd 연대측정법에 중요한 원소군인 Sm과 Nd의 원소분리에 자주 이용되고 있는 HDEHP를 이용한 테플론분말(란탄-레진)법과 Sm-Nd 동위원소계 및 La-Ce 동위원소계의 연구를 위한 원소분리법인 ${\alpha}$-HIBA(${\alpha}$-Hydroxy Isobutyric acid)법의 장단점을 한국지질자원연구원(KIGAM), 기초과학지원연구원(KBSI), 극지연구소(KOPRI) 및 일본 나고야대학과 같은 각 기관별 용리곡선을 통해 비교 소개하였다. 동위원소 지구화학연구를 위한 이 고순도의 원소분리법 비교는 Sm-Nd계 및 La-Ce계 동위원소 지구화학연구자의 실험법 선택에 많은 도움을 줄 것이다.