• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.144-145
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• 2009

• Journal of the Korean earth science society
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• v.22 no.1
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• pp.1-9
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• 2001

Composition of the major and trace elements, Rb-Sr isochron age Sr-Nd isotope composition were determined for foliated in the Jeonju area, in the middle part of the Ogcheon Fold Bet, Korea. The geochemical characteristics of the Jeonju foliated granite indicate that the granite had been crystallized from a calc-alkaline series, and formed in a volcanic are environment. The isotopic compositions of the Jeonju foliated granite give Rb-Sr whole rock errorchron age of 168.2${\pm}$8 Ma(2${\sigma}$), corresponding to the middle Jurassic period, with the Sr initial ratio of 0.71354${\pm}$0.00031. $^{143}$Nd/$^{144}$Nd ratios, ${\varepsilon}$Nd and ${\varepsilon}$Sr values range from 0.511477 to 0.511744, -15.4${\sim}$-21.2, and +108.8${\sim}$+l42.6, respectively. Model ages were caculated to be 1.82${\sim}$2.89Ga. The isotopic data of Jeonju foliated granite indicate that the source material may have been derived from partial melting of continental crust materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.89-94
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• 2007

High duality BiSrCaCuO thin films fabricated by using the i-beam sputtering method at various substrate temperatures, $T_{sub}$ and oxidation gas pressures, $pO_3$. The correlation diagrams of the BiSrCaCuO phases with Tsub and $pO_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi2201 and Bi2223 as well as Bi2212 phases come out as stable phases depending on $T_{sub}$ and $pO_3$. From these results, the thermodynamic evaluation of ${\Delta}H$ and${\Delta}S$, which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase, was performed.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.89-89
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• 2006

• 대한핵의학회:학술대회논문집
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• 1996.05a
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• pp.158-158
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• 1996

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.751-752
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• 2005

• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.237-242
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• 2008

To investigate the trends in the survival rate (SR) for very low birth weight infants (VLBW) and extremely low birth weight infants (ELBWI) in Korea, a total of 43 articles pertaining to SR were analyzed, covering the years from 1967 to 2007. The changes in SR were compared using 5 year periods. The SR for VLBWI has increased remarkably, from 31.8% in early 1960 to 65.8% in early 1990 and 78.8% in early 2000. The SR for ELBWI has increased from 8.2% in early 1960 to 37.4% in early 1990 and 62.4% in early 2000. The SR has improved steeply since early 1990. When the SRs for VLBWI in Korea were compared with those in the U.S.A. and Japan, the figures were 40%, 72%, and 79% in 1985; 65.8%, 82%, and 86% in 1990; 71.3%, 86%, and 88% in 1995; 78.8%, 86%, and 89% in 2000, respectively. Although the recent SRs for VLBWI and ELBWI in Korea has improved rapidly, they have not yet reached the levels in these highly developed countries. To obtain accurate statistics that could be represented as an SR for premature infants in Korea, we have to develop a nationwide network database project.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.78-89
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• 2012

The generated torque of a switched reluctance(SR) motor is highly nonlinear, which makes it difficult to determine the reference current commands for minimum torque ripples. In this paper, we present a computationally simple and efficient method to minimize torque ripples of SR motors based on iterative learning control. The reference current command of each phase minimizing torque ripples is identified in 2-dimensional look-up table form. Our learning control algorithm does not require the torque model, so our method is not affected by model errors and hence is very accurate. In order to justify our work, we present some computer simulation results.

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.155-160
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• 1999

In the natural, there exist several kinds of radioactive isotopes. From atmospheric weapon tests and then some isotopes are naturally radioactivity above all things, nuclear power plant operation and man-made radioactive isotopes concern steadily growing in the environment. During the fission process of nuclear weapon tests and nuclear power plant operation, more than 200 radioactive isotopes are generated. Among them, $^{90}Sr$ and $^{137}Cs$ has been regarded as very important isotopes due to characteristics. In this paper, a quantitative analysis method of environment low level $^{90}Sr$ is studied. Radioactivity level of the environmental $^{90}Sr$ is very low, and it emits continuous beta spectrum, and $^{90}Sr$ exists together with $^{89}Sr$, $^{90}Y$ and other radioactive isotopes. It very difficult to make the quantitative analysis of $^{90}Sr$. For the analysis of low level radioactive strontium, enrich and chemical separation of strontium from the other radioactive isotopes are needed. For the estimation of strontium recovery ratio, so called SGAT(Strontium Gravimetric Analysis Technique) was generally used among the domestic research groups, and chemical procedures were developed appropriation for the SGAT, Recently, by using ICP(Inductively Coupled atomic Plasma emission spectrophotometer), amounts of stable atoms can be measured easily and accurately to the extend of ppm or ppb. In this paper, new chemical procedures are developed to exploits the ICP technique. New developed method has simpler chemical treatment procedures and then it gives more accurate results compared with the traditional SGAT.

• Progress in Superconductivity
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• v.13 no.2
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• pp.85-89
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• 2011

Using the density functional theory and its combination to the dynamical mean field theory (DMFT), we have studied the electronic and magnetic structures of Fe-based superconductors, $AFe_2As_2$ (A=Ca, Sr, Ba). Our results for the electronic structure agree well with existing angle resolved photoemission spectroscopy (ARPES) data. The temperature dependent magnetization has been calculated using DMFT, and the magnetic transition temperatures are reasonably consistent with the experimentally observed trend for three compounds.