• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• 제24권3호
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• pp.1-16
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• 2011

Objective : In the theory of Korean medicine, Scrophulariae Radix (SR) can clear away heat and cool the blood, nourish yin and promote the production of the body fluids, relieve toxin and benefit the throat. The present study was carried out to investigate effects of SR on allergic contact dermatitis (ACD) induced by 2,4-dinitrochlorobenzene (DNCB) in mice. Methods : In this experiment, effects of SR on clinical aspects on the skin, histopathological changes such as spongiosis, mast cell distribution, immune cell infiltration in tissue, spleen / body ratio and production levels of serum cytokines were investigated in vivo. In addition, effects on cell viability and release of b-hexosaminidase and histamine were also investigated in vitro. Results : SR treatment diminished erythema, desquamation and keratosis which were induced by repeated painting of DNCB. Spongiosis and edema were diminished by painting of SR in histopathological observation, infiltrations of mast cell and monocytes were also decreased in SR group. In addition, spleen / body ratio was lowered compared to ADC control group. Production level of IFN-${\gamma}$ in serum was decreased, but level of IL-4 did not affected by SR. Finally, more than 400 ${\mu}g/ml$ of SR treatment groups showed decreased cell viabilities in RBL-2H3 cells. Treatment with over 200 ${\mu}g/ml$ of SR decreased b-hexosaminidase release, and treatment with over 400 ${\mu}g/ml$ decreased histamine release in vitro. Conclusion : these data suggest that SR can decrease symptoms of ACD, then SR is useful to treat patient with ACD.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제37권1호
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• pp.29-35
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• 2000

Luminescent characteristics of SrS:Cu,X TFeL devices fabricated by electron-beam deposition system were studied. The SrS powders were used as the host materials and Cu, $CuF_2,\;Cu_2S$ or CuCl powders were added as the luminescent center. The emission spectra of the SrS:Cu,X TFEL devices strongly depended on coactivators. The luminance($L_{40}$) and efficiency(${\eta}_{20}$) of SrS:$Cu_2S$ TFEL device were 1443 cd/$m^2$ and 2.44 lm/w, respectively. Green color was observed from this TFEL device. The luminous efficiency of SrS:$Cu_2S$ TFEL device was higher than that of ZnS:Tb TFEL device, and it also could be good green phosphors for TFEL devices. The luminance($L_{40}$) and efficiency(${\eta}_{20}$) of SrS:CuCl TFEL device were 262 cd/$m^2$ and 0.26 lm/w, respectively. Blue color was emitted from this TFEL device.

• Analytical Science and Technology
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• 제18권6호
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• pp.469-474
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• 2005

This paper presents a quantitative method of sequential separation of $^{90}Sr$, $^{241}Am$ and Pu radionuclides with an anion exchange resin and a Sr-Spec resin. The Pu isotopes were purified with an anion exchange resin. The americium and strontium fractions were separated from the matrix elements with an oxalate co-precipitation method. Americium fraction was separated from the strontium fraction with iron co-precipitation method and purified from lanthanides with anion exchange resin. Strontium-90 was purified from other hindrance elements with the Sr-Spec resin after oxalate co-precipitation. The measurement of Pu and Am isotopes was carried out by an ${\alpha}$-spectrometer. Strontium-90 was measured by a liquid scintillation counter. The radiochemical procedure of $^{90}Sr$, $^{241}Am$ and Pu radionuclides investigated in this study has been validated by application to IAEA-Reference soils.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제11권2호
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• pp.60-66
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• 2001

($Ba_x$$Sr_{1-x}$)$TiO_3$ (x=0.9, 0.7, 0.5) thin films were prepared on ITO-coated glass by sol-gel method. Perovskite phase formation temperature of BST thin films seemed to be higher than $600^{\circ}C$. Peaks of perovskite phase shift to high diffraction angles as the Sr/(Ba+Sr) ratio was increased, due to the smaller ionic size of $Sr^{2+}$ than $Ba^{2+}$ . As a heating temperature was increased, the grain became coarser. And as Sr/(Ba + Sr) ratio was increased, the grain became finer. Dielectric constants of the BST(50/50) thin film are higher and dielectric losses of that are lower than those of the others. Dielectric constant and dielectric loss of the BST(50/50) thin film were 652 and 0.042 at 1kHz, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.45-48
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• 1998

A BaTiO$_3$ was annexed to SrTiO$_3$, (x)BaTiO$_3$-(1-x)SrTiO$_3$ (0.7$\leq$X$\leq$1) ceramics with stable dielectric and electrical properties in high voltage were manufactured. Structural, dielectric and electrical properties were surveyed with the contents of SrTiO$_3$. The open porosity and sintering density were excellent in 0.9BaTiO$_3$-0.1SrTiO$_3$, the grain size of 0.9BaTiO$_3$-0.1SrTiO$_3$ was maximum at 12.40[${\mu}{\textrm}{m}$]. Increasing SrTiO$_3$ mol ratio, the curie temperature was shifted low temperature and the supreme permittivity was increased. In line with increasing of supplied voltage, permitivity was decreased slightly.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.31.2-31.2
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• 2011

We have investigated frequency dependant conductivity (or permittivity) of low dimensional oxide structures represented by [($Sr_{0.75}$, $La_{0.25}$)$TiO_3$]$_1$/1$[SrTiO_3]_n$ superlattices. The low dimensional oxide superlattice was made by cumulative stacking of one unit cell thick La doped $SrTiO_3$ and $SrTiO_3$ with variable thickness from 1 to 6 unit cell, i,e, [($Sr_{0.75}$, $La_{0.25}$)$TiO_3$]$_1$/$[SrTiO_3]_n$ (n=1, 2, 3, 4, 5, 6). We found two kinds of relaxation when n is 3 and 4, while, inductance component was observed at n=1. This behavior can be explained by electron modulation in ($Sr_{0.75}$, $La_{0.25}$)$TiO_3/SrTiO_3$ superlattices. When n is 1, electrons by La doping well extend to un-doped layer. Therefore, the transport of superlattices follows bulk-like behavior. On the other hand, as n increased, the doped electrons became two types of carrier: one localized and the other extended. These results in two kinds of transport phase. At further increase of n, most of doped electrons are localized at the doped layer. This result shows that dimensionality of the oxide structure significantly affect the transport of oxide nanostructures.

• Journal of Environmental Science International
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• 제26권3호
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• pp.363-371
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• 2017

This study evaluates the adsorption properties of Sr ions in an aqueous solution of the synthetic zeolite (Z-Y1) prepared using coal fly ash generated from a thermal power plant. In order to investigate the adsorption characteristics, the effects of various parameters such as the initial concentrations of Sr ion, contact time, and solution pH were investigated in a batch mode. The Langmuir and Redlich-Peterson model fitted the adsorption isotherm data better than the Freundlich model. The maximum adsorption capacity of Sr ions, as determined the Langmuir model, was 181.68 mg/g. It was found that by varying the Sr ion concentration, pH, and temperature, the pseudo-second-order kinetic model describes the adsorption kinetics of the Sr ion better than the pseudo-first-order kinetic model. The calculated thermodynamic parameters of ${\Delta}H^0$ and ${\Delta}G^0$ showed that the adsorption of Sr ions on Z-Y1 was occurred through a spontaneous and an endothermic reaction. We found that the adsorption of Sr ions by Z-Y1 was more affected by pH than by temperature and Sr ion concentration.

• Economic and Environmental Geology
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• 제30권2호
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• pp.153-161
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• 1997

Diagrams of $^{87}Sr/^{86}Sr$ versus Ba/Nb and MgO/FeO are scattered, and $^{87}Sr/^{86}Sr$ variation with the increase of $SiO_2$ are scattered in Gwangju granitoid. Diagrams of $(^{87}Sr/^{86}Sr)$i versus $(^{143}Nd/^{144}Nd)$i and ${\varepsilon}Nd$ versus 1/Nd variation are also scattered in Gwangju granitoid. It shows that the source magma of Gwangju granitoid are derived from partial melting materials of heterogeneous upper crust. Very low ${\varepsilon}Nd$ values (-15.19~-19.49) and very high ${\varepsilon}Sr$ values (92.72~308.85) mean that the source magma of Gwangju granitoid is derived from sedimentary substance melting. According to $(^{87}Sr/^{86}Sr)$ 180Ma, and the plot of ${\varepsilon}Sr$ versus ${\varepsilon}Nd$, the Gwangju granitoid shows that the source magma is derived from upper crust materials. Nd model ages of Gwangju granitoid (1.82~2.42G.A.) are older than meta-sediments of Okcheon formation (1.15~1.60G.A.) and similar or close to Pre-Cambrian gneiss complex of Ryoungnam massif (2.17~2.47G.A.or 2.11~2.38G.A.).Therefore, the source magma of the Gwangju granitoid could be derived from the partial melting of Pre-Cambrian gneiss complex of Ryoungnam massif.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.822-826
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• 2008

We report the cathodoluminescence and aging properties of a series of green phosphors of formula $Sr_{1-x}M_xGa_2S_4$:Eu (x = 0.0-1.0, M = Ba or Ca) that have potential applications in field emission displays (FEDs). The series of phosphors was synthesized via NaBr-aided solid-state reactions in a flowing $H_2S$ stream. A low level ($\sim$20%) of Ba or Ca substitution for Sr in $SrGa_2S_4$:Eu maintains the orthorhombic phase of pure $SrGa_2S_4$:Eu phosphors. Further, a low level ($\sim$20%) of Ba or Ca substitution for Sr in $SrGa_2S_4$:Eu provides various green colors and sufficient brightness for FED applications. Substitution of Ba or Ca for Sr in $SrGa_2S_4$:Eu also improved the stability of the phosphor when it was operated under electron-beam irradiation of 5 kV.

• Journal of the Korean Ceramic Society
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• 제28권3호
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• pp.215-224
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• 1991

The synthesis of SrTiO3 powders having high purity and homogeneous submicron particle size was attempted by the oxalate method. The microstructure and dielectric properties of SrTiO3 based boundary layer capacitor (BLC) were investigated. Strontium titanyl oxalate[SrTiO(C2O4)2.4H2O] was prepared from the mixing solution of (Sr, Ti) using oxalic acid(H2C2O4) as a precipitating agent at 8$0^{\circ}C$. The crystalline SrTiO3 powder was obtained by thermal decomposition of the precipitate above $600^{\circ}C$. The crystalline SrTiO3 powder containing Nb2O5 as a dopant, TiO2 and SiO2 as additives was sintered at 1360~144$0^{\circ}C$ in the reducing atmosphere to get semiconductive SrTiO3. Insulating material containing PbO-Bi2O3-B2O3 frit was printed on the sintered semiconductive SrTiO3 and fired at 120$0^{\circ}C$ for 2h to get the grain boundary diffusion.