통합 검색 | Korea Science

곽훈;이정구;최철진
- 한국분말재료학회지
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- 제16권5호
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- pp.336-341
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- 2009
To produce alloy powders with only Sm$_2$Fe$_{17}$ single phase by reduction-diffusion (R-D) method, the effect of excess samarium oxide on the preparation of Sm-Fe alloy powder during R-D heat treatment was studied. The quantity of samarium oxide was varied from 5% to 50% whereas iron and calcium were taken 0% and 200% in excess of chemical equivalent, respectively. The pellet type mixture of samarium, iron powders and calcium granulars was subjected to heat treatment at 1100$^{\circ}C$ for 5 hours. The R-D treated pellet was moved into deionized water and agitated to separate Sm-Fe alloy powders. After washing them in deionized water several times, the powders were washed with acetic acid to remove the undesired reaction products such as CaO. By these washing and acid cleaning treatment, only 0.03 wt% calcium remained in Sm-Fe alloy powders. It was also confirmed that the content of unreacted $\alpha$-Fe in Sm$_2$Fe$_{17}$ matrix gradually decreased as the percentage of samarium oxide is increased. However, there was no significant change above 40% excess samarium oxide.
https://doi.org/10.4150/KPMI.2009.16.5.336 인용 PDF KSCI

Ko, Kwang-Hoon;Moon, Hee-Jong;Park, Hyun-Min;Lee, Jong-Min;Lee, Won-Kyu;Lee, Jai-Hyung;Chang, Joon-Sung
- Journal of the Optical Society of Korea
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- 제4권2호
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- pp.75-78
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- 2000
We design a high temperature oven for measuring the saturation intensity of the transition line $4f^ 6/6s^{2 7}7F_0 ↔ 4f^6/6s6p $^1$P(J = 1)$ of the samarium atom. We first constructed a high temperature oven to generate the samarium vapor column and study the thermal characteristics of the oven. The oven is able to operate at a temperature up to about 1400 $^{\circ}C$ and the operation is tested by using several metals with high melting points. We describe two wave mixing experiment with the samarium vapor generated in the high temperature oven and obtain the saturation intensity by analyzing the first diffraction signal.
https://doi.org/10.3807/JOSK.2000.4.2.075 인용 PDF

차기원;박광원;하영구;김하석
- 대한화학회지
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- 제38권9호
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- pp.653-659
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- 1994
pH 7인 수용액에서 2-thenoyltrifluoroacetone(TTA), n-octanol과 Triton X-100의 존재하에서 유로퓸과 사마륨의 형광세기가 크게 증가하였다. 또한 이 착물에 과량의 $La^{3+}$을 첨가할 때 형광세기가 100배 이상 증가하였다. 유로퓸과 사마륨의 최대 들뜨기 파장은 각각 345 nm과 380 nm이고, 최대 형광파장은 각각 617 nm, 567 nm 이었다. 유로퓸과 사마륨의 형광세기는 농도가 각각 $1{\times}10^{-7}∼1{\tiems}10^{-9}\;M,\;1{\tiems}10^{-5}∼1{\times}10^{-7}\;M$에서 직선적으로 증가하였고, 유로퓸은 $1{\times}10^{-11}\;M$ 그리고 사마륨은 $1{\times}10^{-8}\;M$까지 검출할 수 있었다.
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김미자;이명종
- Restorative Dentistry and Endodontics
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- 제13권1호
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- pp.69-78
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- 1988
The study was designed to establish a more nearly quantitative method for assessing the marginal leakage of dental restorations. 27 Class V cavities with $45^{\circ}$ bevel joint were prepared and classified into 2 groups. One group was filled with Scotchbond and silux. The other group was filled with glass ionomer cement, Scotchbond and silux. After finishing, all specimens were subjected manually to 100 thermal cycles at $0^{\circ}C$ and $100^{\circ}C$ water-bath. They were soaked in a samarium nitrate solution for 3 hours, irradiated with flux of $6{\times}10^{12}$ neutrons/$cm^2$/sec for 11 hours, cooled for 200 hours, counted with the HPGE detector and the tracer uptake was determined by comparison with a standard of samarium (10 ${\mu}g$). The following results were obtained. 1. Both of the two groups showed a considerable amounts of marginal leakage. 2. The group filled without glass ionomer cement base showed more marginal leakage than the group filled with glass ionomer cement base. 3. Neutron Activation Analysis produced a good quantitative method to measure the marginal leakage and samarium was appropriate to measure the marginal leakage of resin restorations using neutron activation analysis.
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