Search | Korea Science

Kwak, Hun;Lee, Jung-Goo;Choi, Chul-Jin
- Journal of Powder Materials
- /
- v.16 no.5
- /
- pp.336-341
- /
- 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
- /
- v.4 no.2
- /
- pp.75-78
- /
- 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

Cha, Gi Won;Park, Gwang Won;Ha, Yeong Gu;Kim, Ha Seok
- Journal of the Korean Chemical Society
- /
- v.38 no.9
- /
- pp.653-659
- /
- 1994
The fluorescence intensities of europium and samarium can be greatly enhanced in the presence 2-thenoyltrifluoroacetone(TTA), n-octanol and Triton X-100 in aqueous solution of pH 7. It was also found that the fluorescence intensity can be greatly increased by the addition of excess of $La^{3+}$. The excitation and emission wavelengths of europium and samarium were 345 nm, 380 nm and 617 nm, 567 nm, respectively. The fluorescence intensity was a linear function of the concentration of europium and samarium in the range TEX>$1{\times}10^{-7}∼1{\tiems}10^{-9}\;M,\;1{\tiems}10^{-5}∼1{\times}10^{-7}\;M$, respectively, and the detection limits were 1$1{\times}10^{-11}\;M$ for europium and $1{\times}10^{-8}\;M$ for samarium and the luminescence mechanism of the system is discussed.
PDF

Kim, Mi-Ja;Lee, Myung-Jong
- Restorative Dentistry and Endodontics
- /
- v.13 no.1
- /
- pp.69-78
- /
- 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.
PDF