• Journal of the Korean Chemical Society
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• v.25 no.1
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• pp.21-25
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• 1981

A study was made of the influence of butyl alcohol on the distribution coefficients of barium and mercury ions between the ion exchange resin, Dowex 50w-x8, 200~400 mesh and solutions containing hydrochloric acid, butyl alcohol and water. The determination of the distribution coefficients of barium and mercury are made by using the batch method. The distribution coefficients of metal ions decrease generally as the number of branches of carbon in the molecule of butyl alcohol increase. It shows that solubility in water and stereo-isomerism of the butyl alcohol have influence upon the distribution coefficient of barium and mercury.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.1-10
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• 1999

We sought to find out the mechanism of vascular relaxation by extracellular $K^+$ concentration $([K^+]_o)$ in the cerebral resistant arteriole from rabbit. Single cells were isolated from the cerebral resistant arteriole, and using voltage-clamp technique barium-sensitive $K^+$ currents were recorded, and their characteristics were observed. Afterwards, the changes in membrane potential and currents through the membrane caused by the change in $[K^+]_o$ was observed. In the smooth muscle cells of cerebral resistant arteriole, ion currents that are blocked by barium, 4-aminopyridine (4-AP), and tetraethylammonium (TEA) exist. Currents that were blocked by barium showed inward rectification. When the $[K^+]_o$ were 6, 20, 60, and 140 mM, the reversal potentials were $-82.7{\pm}1.0,\;-49.5{\pm}1.86,\;-26{\pm}1.14,\;-5.18{\pm}1.17$ mV, respectively, and these values were almost identical to the calculated $K^+$ equilibrium potential. The inhibition of barium-sensitive inward currents by barium depended on the membrane potential. At the membrane potentials of -140, -100, and -60 mV, $K_d$ values were 0.44, 1.19, and 4.82 ${\mu}M,$ respectively. When $[K^+]_o$ was elevatedfrom 6 mM to 15 mM, membrane potential hyperpolarized to -50 mV from -40 mV. Hyperpolarization by $K^+$ was inhibited by barium but not by ouabain. When the membrane potential was held at resting membrane potential and the $[K^+]_o$ was elevated from 6 mM to 15 mM, outward currents increased; when elevated to 25 mM, inward currents increased. Fixing the membrane potential at resting membrane potential and comparing the barium-sensitive outward currents at $[K^+]_o$ of 6 and 15 mM showed that the barium- sensitive outward current increased at 15 mM $K^+.$ From the above results the following were concluded. Barium-sensitive $K^+$?channel activity increased when $[K^+]_o$ is elevated and this leads to an increase in $K^+-outward$ current. Consequently, the membrane potential hyperpolarizes, leading to the relaxation of resistant arteries, and this is thought to contribute to an increase in the local blood flow of brain.

• Journal of the Korean Magnetics Society
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• v.19 no.6
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• pp.216-221
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• 2009

Y-type barium ferrite $Ba_2Co_2Fe_{12}O_{22}$ was synthesized by a solid state reaction method. Effects of metal ion mole ratio and calcination temperatures on magnetic properties and microstructures of the synthesized powders were investigated. Phase analysis and microstructure observation were performed with a XRD (X-ray diffractometer) and a FESEM (field effect scanning electron microscope), respectively. Magnetic properties of the powders were measured with a VSM (vibrating sample magnetometer). Single phase Y-type was synthesized when metal ion mole fraction $Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$ was 6 : 1 : 1 and calcination temperature was $1050\;{^{\circ}C}$. High saturation magnetization value of 39.1 emu/g was obtained when metal ion mole fraction $Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$ was 8 : 1 : 1 and calcination temperature was $1200\;{^{\circ}C}$.

• Korean Journal of Crystallography
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• v.17 no.2
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• pp.51-54
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• 2006

BaO layers were formed on the Si(100) surface by thermal evaporation of barium metal with simultaneous oxidation. The atomic structure of BaO layers at the initial stage of the deposition was investigated by the scattering intensity variation of $He^+$ions on time-of-flight (TOF) impact-collision ion scattering (ICISS). The results show that several number of BaO layers are formed on the Si(100) surface with the lattice parameter of bulk phase, and the occupation of oxygen atoms of the BaO layers is on-top site of silicon atoms.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.371-380
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• 1989

The purpose of this experiment is to elucidate the reaction mechanism concerning to the formation of crystalline BaTiO3 synthesized by adding the pH control agent(KOH soln) in TiCl4 and BaCl2 solution (Wet direct synthetic method). In this expeirment, it is identified that the amorphous barium-titanate having Ba-O-Ti bonding is formed above pH5 due to the -OH- ion and Ti-gel is formed below pH5 due to the polymerization of metatitanic acid. The bonding of the amorphous Ba-O-Ti is identified by FT-IR spectrum and crystallization temperature is about 82$0^{\circ}C$. If the pH of the above system according to the -OH- ion concentration is above 13.8, the polymerized metatitanic acid will be depolymerized and produce [TiO3]2+ion and crystalline BaTiO3 is formed by reacting the produced [TiO3]-- ion with the active Ba++ ion.

• Journal of the Korean Ceramic Society
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• v.30 no.12
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• pp.1066-1070
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• 1993

When looked upon as a polycrystalline, ceramics have two basic differences from a single crystal. One is that there exist grain boundaries, the other is that the crystal axes of each small crystal are arranged in random directions. But the crystal axes fo small crystals which compose ceramics may be made to have the tendency of being arranged in a specific direction. This is called that the crystal axes are oriented. The degree of the direction arrangement of the crystal axes is called orientation. In order to orient the crystal axes effectively, the fiberous barium titanates were made through KDC method and the ion exchange method. And then they were arranged through pressing, doctor blade, and syringe. As the result of Lotgering evaluation, the sample oriented through syringe showed the highest orientation. After sintering, though the most particles that had been fiberous shaped became global shape viewed through SEM, the orientation of the crystals was reinforced by means of sintering.

• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.678-679
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• 2006

The effects of particle size on the surface properties of hydro-thermally synthesized barium titanate powders were investigated by means of particle size analysis, specific surface area, SEM, zeta potential and XPS. Particle sizes were measured by laser light scattering and are in the range of 150 to 1100nm. Zeta potential increased with increasing particle size and it was large minus value in the range of particle size from 500 to 900nm, which seems to be related with the dissolution of $Ba^{2+}$ ion in these particle sizes from the analysis of surface properties by XPS.

• Korean Journal of Microbiology
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• v.22 no.1
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• pp.57-66
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• 1984

Cells of Stigmatella aurantiace developed in the light on the medium containing calcium, barium, or lithium ion formed fruiting bodies without stalk. Fruiting body with stalk was formed on the medium containing calcium ion and GMP (GMP-medium) even under the dark condition. On the medium containing calcium and pheromone (pheromone-medium), most cells were developed only into the stalk in the light and into the sporangium in the dark. The number of aggregate formed on the medium containing calcium ion (Ca-medium) was more than that formed on the medium containing calcium, potassium, and sodium ions (CPS-medium). The number of aggregate formed on the GMP or pheromone-medium was less than that formed on the Ca-medium. Both pheromone and GMP reduced the time required for aggregate formation when cells were developed in the dark. Light stimulated cells to form more aggregates in short time when it was introduced into the Ca-, CPS-, GMP-, or pheromone-medium.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.349-356
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• 1988

The PTCR characteristics of (Ba0.8Pb0.2)TiO3 ceramics prepared by the molten salt sysnthesis (MSS) method have been investigated as a function of the amount of Nb2O5 dopant and KCl flux. When the weight ratio of KCl to raw material is 0.8, the resistivity at room temperature decreases with increasing amount of Nb dopant up to 0.6 atom%. It can be explained by compensation for electrons due to Nb+5 ion and holes due to K+ ion. The resistivity of (Ba0.8Pb0.2)(Ti0.994Nb0.006)O3 ceramics at room temperature decreases with increasing the ratio of KCl to raw material up to 0.6, and then increases. These results can be explained by the effect of K+ ion.