• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.113-117
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• 1999

SrBi$_2$Ta$_2$$O_{9}$ (SBT) thin films were fabricatcd with different Sr/Bi ratios by MOD. SBT thin films of thickness 2500$\AA$ deposited on Pt/Ti/SiO$_2$/Si were crystallized at $700^{\circ}C$ ~85$0^{\circ}C$ using RTA method. As the Sr/Bi ratio was decreased, dielectric constant and remanent polarization were increased. SrBi$_2$Ta$_2$$O_{9}$ showed a maximum dielectric constant value of $\varepsilon$$_{r}$= 268, and maximum remanent polarization (2Pr) of ~9.86 $\mu$C/$\textrm{cm}^2$ when annealed at 8$0^{\circ}C$ for 8 min.min.n.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.148-149
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• 2009

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.209-212
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• 1995

In this paper, the $(Sr_{0.85}{\cdot}Ca_{0.15})TiO_3$ of paraelectric grain boundary layer (GBL) ceramics were fabricated. The characteristics of electrical conduction and the thermally stimulated current(TSC) were measured respectively. The region I below 200[V/cm] shows the ohmic conduction, the region II between 200[V/cm] and 1000[V/cm] can be explained by the Pool-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect. As a result, The origins of these peaks are that the ${\alpha}$ peak observed at $-20[^{\circ}C]$ looks like to be ascribed to the ionization excitation from donor level in the grain, and the ${\alpha}^{\prime}$ peak observed at $-20[^{\circ}C]$ appears to show up by detrap of the trapped carrier of border between the oxidation layer and the grain, and the ${\beta}$ peak observed at $80[^{\circ}C]$ seems to be resulted from hopping conduction of existing carrier in the trap site of the border between the oxidation and second phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.239-242
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• 1998

The (S $r_{0.85}$C $a_{0.15}$)Ti $O_3$ (SCT) thin films are deposited on Pt-coated electrode using RF magnetron sputtering method at various substrate temperature. Dielectric constant of SCT thin films is increased with increased as the deposition temperature and changes almost linearly in temperature ranges from -80 to +90[$^{\circ}C$]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz]. V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature.ure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.802-807
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• 2001

The (S $r_{0.85}$C $a_{0.15}$)Ti $O_{3}$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/ $SiO_2$/Si) using RF sputtering method. The composition of SCT thin films deposited on Si substrate at woom temperature is close to stoichiometry(1.102 in A/B ratio). The maximum dielectric constant of SCT thin films is obtained by annealing at 600[$^{\circ}C$]. The capacitance characteristics had a stable value within $\pm$4[%]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz]. SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequencey.cey.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.21-30
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• 2000

For analyzing the direct contamination pathway of radionudides in rice plants, a Solution containing $^{54}Mn,\;^{57}Co,\;^{85}Sr,\;^{103}Ru$ and $^{134}Cs$ was applied to the aboveground Parts of the between RI application and harvest. Its highest observed value was 0.94. The fractions of the initial plant deposition that remained in rice plants at harvest were in the range of $19{\sim}47%,\;17{\sim}43%,\;19{\sim}42%,\;23{\sim}61%$ and $11{\sim}69%$ for $^{54}Mn,\;^{57}Co,\;^{85}Sr,\;^{103}Ru$ and $^{134}Cs$, respectively, when no decay was assumed. The translocation factors of those radionuclides in hulled seeds were in the range of $6.9{\times}10^{-4}3.8{\times}10^{-2},\;3.6{\times}10^{-3}{\sim}1.6{\times}10^{-1},\;5.8{\times}10^{-4}{\sim}3.2{\sim}10^{-2},\;1.6{\times}10^{-4}{\sim}7.6{\times}10^{-3}$ and $3.2{\times}10^{-2}{\sim}2.0{\times}10^{-1}$, respertively, and were highest when they were applied at the stage of active seed development. It was indicated that the remaining percentage and translocation factor would not be greatly affected by the difference in the rain frequency if it is within a factor of 2. These results can be utilzed for predicting the radionuclide concentrations in rice seeds when an accidental deposition of those radionuclides occurs during the rice-growing season.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.78-85
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• 1995

Ornithine decarboxylase(ODC) is an indicate enzyme in carcinogenesis. We divided Sprague Dawley rats into six groups: control, electric field exposure, X-ray only irradiation, X-ray irradiation with electric field exposure group, Sr-90 injected group and Sr-90 and electric field complex exposure group. The ODC activity was measured in rat's bone marrow cell every week. The results were summarized as follows: The ODC activitied was increased in X-ray irradiated, Sr-90 injected and Sr-90 and electric field complex exposed group as compared with that of control(p<0.05). The ODC activity was increased comparing that of control neither in X-ray and electric field complex exposed group nor electric field only exposed group. This result suggests that the electric field doesn't have myeloid carcinogenicity and myeloid cancer incidence caused by ionized radiation is suppressed by electric field exposure.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1003-1008
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• 1997

The (La, Sr)MnO3 powder used as air-electrode material of Solid Oxide Cell (SOFC) was synthesized by Modified-GNP(Modified-Glycine Nitrate Process). The powders were prepared using oxide and carbonate stable in atmosphere and nitric acid was used as a solvent of starting material as well as an oxidant for combustion. The (La, Sr)MnO3 powders were synthesized with 0.5, 1, 2, 3, 4 of glycine/cation molar ratio. The ICP (Inductively Coupled Plasma Mass Spectrometer) result represented compositional equality between synthesized and desired powders. In case of 2 molar ratio, the as-synthesized powder showed perovskite phase and specific surface area were 19 $m^2$/g. After calcination of 85$0^{\circ}C$, the calcined powder except 0.5, 1 molar ratio of glycine to cation showed perovskite phase.

• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.7-14
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• 1999

Wekk oriented $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ suppercondcting thick films were fabricared on copper tape by LiReac-PreCu (liquid reaction between a Cu-free precousor and Cu tape) method. Cu-free precursor power which is composed of $Bi_{2}Sr_{2}Ca_{5}$ was printed on a copper tape by screen printing and was heat-treated. The speciment were partially in a molten state at the heat treatment temperature (85$0^{\circ}C$~87$0^{\circ}C$). The heat heat treatments for the reaction were performed in air or low oxygen pressure in several stages. XRD analyses of the resulting Bi2Sr2CaCu2O8 superconducting tapes show that the $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ phase is dominant and a small amount of $Bi_{2} Sr_{2} Cu_{2} O_{6}$ phase is detected. Both phases are aligned in the c-axis direction.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.804-809
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• 2011

Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes were prepared by extrusion. TGA results of green body membrane after extrusion showed three successive weight losses due to decomposition of organic additives and carbonate. Drying shrinkage rate of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes was no change after 68 h and higher in the membrane with large outer diameter. XRD and SEM results showed the sintered membranes were the single phase structure and dense. The stoichiometric molar ratio agreed well with composition ratio calculated by EDS results for $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane. Radial crushing strength of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane with 0.95 mm thickness was 5.7 kgf/$mm^2$ and the oxygen permeation rate of same membrane was 146.85 mL/min ($Jo_2$=2.33 mL/$min{\cdot}cm^2$) at $950^{\circ}C$. Therefore, it was known that use of vacuum pump was more effective than that of sweep gas to obtain higher oxygen permeation flux.