• Journal of the Korea Academia-Industrial cooperation Society
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• v.1 no.1
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• pp.27-32
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• 2000

Porous glass ceramics composed of $Ag_2-Li_2O-CaO-TiO_2-P_2O_5$-CaO with 0.05-1.5 mole CuO were prepared by melting and 2 step heat treatment for nucleation at $610^{\circ}C$ and crystallization at $840^{\circ}C$. $\beta$-$Ca_3(PO_4)_2$crystal phase was selectively leached out in 1N-HC1 solution for 3 days, leaving $AgTi_2(PO_4)_3$and $LiTi_2(PO_4)_3$crystal phases. Antibacterial effects and characterizations of the porous glass ceramics were investigated. Staphylococcus aureus and Salmonella typhi bacteroa were used in this study. It was found that the resultant porous glass ceramics show excellent bacteriostatic properties.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.223-229
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• 2006

To develop multifunctional microbial inoculant, an insluble phosphate-solubilizing bacterium with antifungal activity was isolated from plant rhizospheric soil. On the basis of its morphological, cultural and physiological characteristics and Biolog analysis, this bacterium was identified as Pseudomonas fluorescens RAF15. P. fluorescens RAF15 showed antifungal activities against phytopathogenic fungi Botrytis cinerea and Rhizoctonia solani. The optimal medium composition and cultural conditions for the solubilization of insoluble phosphate by P. fluorescens RAF15 were 1.5% of glucose, 0.005% of urea, 0.3% $MgCl_2{\cdot}6H_2\;0.01%\;of\;MgSO_4{\cdot}7H_2O\;0.01%,\;of\;CaCl_2{\cdot}2H_2O$, and 0.05% of NaCl along with initial pH 7.0 at $30^{\circ}C$. The soluble phosphate production under optimum condition was 863 mg/L after 5 days of cultivation. The solubilization of insoluble phosphates was associated with a drop in the pH of the culture medium. P. fluorescens RAF15 showed resistance against different environmental stresses like $10-35^{\circ}C$ temperature, 1-4% salt concentration and pH 2-11 range. The strain produced soluble phosphate to the culture broth with the concentrations of 971-1121 mg/L against $CaHPO_4$, 791-908 mg/L against $Ca_3(PO_4){_2}$, and 844 mg/L against hydroxyapatite, respectively. However, the strain produced soluble phosphate to the culture broth with the concentrations of 15 mg/L against $FePO_4$, and 5 mg/L against $AlPO_4$, respectively.

• Membrane and Water Treatment
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• v.2 no.3
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• pp.187-205
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• 2011

The electric transport of the mixture of hydrochloric and phosphoric acids through strong base (Neosepta ACM) and weak base (Selemion AAV) anion-exchange membranes was investigated. The instantaneous efficiency of HCl removal from the cathode solution, $CE_{Cl}$, with and without $H_3PO_4$ was determined. It was found that $CE_{Cl}$ was 0.8-0.9 if the number of moles of elementary charge passed through the system, $n_F$, did not exceed ca. 80% of the initial number of HCl moles in the cathode solution, $n_{Cl,ca,0}$. The retention efficiency of $H_3PO_4$ in that range was close to one. The transport of acid mixtures was satisfactorily described by a model based on the extended Nernst-Planck and Donnan equations for $n_F$ not exceeding $n_{Cl,ca,0}$. Among the tested model parameters, most important were: concentration of fixed charges, the porosity-tortuosity coefficient, and the partition coefficient of an undissociated form of $H_3PO_4$. For the both membranes, the obtained optimal values of fixed charge concentration, $\bar{c}_m$, were up to 40% lower than the literature values of $\bar{c}_m$ obtained from the equilibrium measurements. Regarding the $H_3PO_4$ equilibria, it was sufficient to consider $H_3PO_4$ as a monoprotic acid.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.51-55
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• 2003

To develop environment-friendly biofertilizer solubilizing insoluble phosphates, a bacterium possessing a high ability to solubilize $Ca_{3}(PO_{4})_{2}$) was isolated from the rhizosphere of peas. On the basis of its morphological, cultural, physiological characteristics, and Vitek analysis, this bacterium was identified as Pantoea agglomerans. The optimal medium composition and cultural conditions for the solubilization of insoluble phosphate by P. agglomerans R-38 were 3% of glucose.0.1% of TEX>$NH_{4}NO_{3}$, 0.02% of $MgSO_{4}\cdot\7H_{2}O$, and 0.06% of $CaCl_{2}\cdot\2H_{2}O$ along with initial pH 7.5 at $30^{\circ}C$. The highest soluble phosphate production under optimum condition was 898 mg/L after 5 days of cultivation. The solubilization of insoluble phosphate was associated with a drop in the pH of the culture medium. The strain produced soluble phosphate to the culture broth with the concentrations of 698 mg/L against CaHPO$_4$, 912 mg/L against hydroxyapatite, 28 mg/L against $FePO_{4}\cdot\4H_{2}O$, and 19 mg/L against $AIPO_{4}$, respectively.

• The Korean Journal of Physiology
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• v.16 no.1
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• pp.69-76
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• 1982

The effect of parathyroid hormone on calcium and phosphate metabolism have been widely investigated, however less attention has been paid to the effect on urinary excretion. This study was performed for the purpose determining urinary excretion of Na, K, Ca, and $Po_4$, of 18 thyroparathyroidectomized (TPTX) rabbits, which were TPTX previously 7 to 10 days compared with the same normal ones. After TPTX 0.2 mg/day of synthyroid was donated to the rabbits. The concentration of electrolytes in the serum and urine was determined by the following method; Na and K were determined by means of flame photometry, Ca was by EDTA titration $method^{19)}$, and $Po_4$ by Fiske and Subba-Raw $method^{20)}$. The results as follows. The concentrations of electrolytes in the serum were 1) In the normal control rabbits (N = 25) (data, $Mean{\pm}S.E.$) $Na\;131.72{\pm}1.33\;mEq/L$, $K\;3.59{\pm}0.28\;mEq/L$, $Ca\;12.58{\pm}0.29\;mg%$, $Po_4\;4.50{\pm}\;0.45mg%$. 2) In the TPTX rabbits(N= 18) $Na\;140.6l{\pm}2.56\;mEq/L$, $K\;3.38{\pm}0.36\;mEq/L$, $Ca\;l2.18{\pm}0.45\;mg%$, $Po_4\;3.92{\pm}\;0.35\;mg%$. There was no significant change between the normal and TPTX rabbits. The concentration of elelctrolytes in the urine were variously changed. 3) In the normal rabbits. $Na\;8.40{\pm}1.09\;mEq/L$, $K\;81.59{\pm}10.19\;mEq/L$, $Ca\;16.02{\pm}3.12\;mg%$, $Po_4\;13.16{\pm}2.89mg%$. 4) In the TPTX rabbits, $Na\;14.57{\pm}3.39\;mEq/L$ slight ncreased, $K\;116.06{\pm}12.77\;mEq/L$ significant increased (P<0.05), $Ca\;18.90{\pm}5.44\;mg%$ no significant increased, $Po_4\;43.38{\pm}8.67\;mg%$ significant increased (p<0.01). The effect of TPTX was assumed that it affected upon increasing tubular secretion of $K^+$ and inhibition of the tubular reabsorption of $Po_4$.

• Korean Journal of Materials Research
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• v.16 no.10
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• pp.624-628
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• 2006

In this study, divalent europium-activated $NaCaPO_4$ green phosphor powders were prepared by the chemical synthetic method followed by heat treatment in reduced atmosphere, and the crystal structures, morphologies and photoluminescent properties of the powders were investigated by x-ray powder diffraction, scanning electron microscope and spectrometer for the first time. The effects of Ca/P and Na/Ca mole ratios on the final products were also investigated. The influences of input amount change of europium as the activator on the light emission intensity were studied, and the resulting concentration quenching phenomenon was observed. The optimized synthesis conditions obtained in this study were Ca/P mole ratio 1.2, Na/Ca mole ratio 3.0 and 4 mole%Eu. The peak wavelength was 505 nm for all the samples. The result of excitation spectrum measurement indicated that the excitation efficiency was high for the long-wavelength UV region. It was thus concluded that the samples prepared in this study can be successfully applied for the light-emitting devices such as LED excited with long-wavelength UV light sources.

• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.7-16
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• 1996

${CO_3}^{2-}$ containing whisker-like hydroxyapatite powders were synthesized byhomogeneous precipitation method using urea, Dicalcium phosphate anhdrate[DCPA; $CaHPO_4$] and octacalcium phosphate [OCP; $Ca_8H_2(PO_4_)6\cdot5H_20$]were obtained as precursors and they transformed to high crystalline hydroxyapatites at pH 5.62, and 6.54 respectively. According to the condition of the final pH in the solutions for the solution products and urea contents OCP was remained. When the solution product of $Ca^{2-}$ and ${PO_4}^{3-}$ was $1.5\times 10^4$[$mM^2$] and the content of urea was 0.25 mol.$dm^{-3}$ well crystallized whisker-like hydroxyapatite tens of micrometer in length was obtained. By heat treatment DCPA and OCP were decomposed into $\beta$-tricalcium phosphate [$\beta$-TCP ; $\beta$-$Ca_3{PO_4}_2$] and $\beta$-dicalcium phosphate [$\beta$-DCP ;$\beta$-$Ca_2P_2O_4}_2$]. And well-crystallized hydroxyapatite was partially decomposed into $\beta$-TCP at $800^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.16 no.4
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• pp.213-224
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• 1979

The present work was undertaken: (1) to determine if CaO-partially stabilized $ZrO_2$ prepared by Hot Petroleum Drying Method would show better ionic conductor as an oxygen sensor in molten metals than that prepared by Oxide Wet Mixing Method and than CaO-fully stabilized $ZrO_2$, and (2) to understand the nature of conduction mechanism of CaO-partially stabilized $ZrO_2$ by a comparison of measured electrical conductivity data with theory on defect structure of pure monoclinic $ZrO_2$ and fully stabilized cubic $ZrO_2$. The DC electrical conductivity was measured by 3-probe technique and the AC electrical conductivity by 2-probe technique as a function of temperature in the range 973-1373 K and oxygen partial pressure in the range 10-1-10-25Mpa. The results of the experiments were as follows: 1. CaO-partially stabilized $ZrO_2$ prepared by Hot petroleum Drying Method showed at T=1094-1285 K and $Po_2$=10-7-10-25 MPa a nearly ionic conduction with 4 times higher conductivity than that prepared by Oxide Wet Mixing Method. 2. High-oxygen pressure conductivity tends toward a Po_2^{+1/5}-Po_2^{+1/6}$dependence. An analysis of possible defect structures suggests that CaO-partially stabilized $ZrO_2$ has an anti-Frenkel defect in which singly or doubly ionized oxygen interstitials and defect electrons predominate at T=1094-1285 K and $Po_2$=10-1-10-7MPa. 3. The activation energy for pure electron hole-conduction and ionic conduction of CaO-partially stabilized $ZrO_2$ was found to be 130 KJ/mol at T=973-1373 K, $Po_2$=2, 127 10-2 MPa(air) and 153KJ/mol at T=1094-1285 K respectively.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.469-471
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• 2001

Dry grinding of a mixture of CaCO$_3$ and Ca(H$_2$PO$_4$)$_2$.$H_2O$ was conducted using a planetary ball mill in order to investigate solid state reaction for a synthesis of hydroxyapatite(Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$, HAp) through mechanochemical treatment method. The raw materials, which are composed of waste oyster and calcium biphosphate Ca(H$_2$PO$_4$)$_2$.$H_2O$, were mixed and then treated mechanochemically. The synthesis of hydroxyapatite(Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$, HAp) from the mixture was almost completed by about 60 minute grinding. The formation of HAp monophase in the ground mixture was characterized through X-ray diffraction (XRD) analysis. Moreover, the formation of HAp monophase depending on the grinding time was improved by increasing the grinding time.ime.ime.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.188-191
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• 2013

This study was carried out to investigate the effects of light, temperature, and priming treatment on the germination of Bidens bipinnata seeds for the purpose of cultivation of new vegetable crop. The results showed that the treatment of $25^{\circ}C$ yielded the highest germination percentages and the highest germination speed in both light and dark conditions. Light condition had no effect on the germination of B. bipinnata. Priming treatments demon-strated the following improved germination percentages: $Ca(NO_3)_2$ 0.1 M (68.3%), $K_3PO_4$ 0.1 M (63.3%), and $KNO_3$ 0.1 M (53.3%), with $Ca(NO_3)_2$ 0.1 M treatment giving the greatest improvement. Consequentially, the results suggested that $25^{\circ}C$ light condition, and $K_3PO_4$ 0.1 M or $Ca(NO_3)_2$ 0.1 M priming treatments would be effective method to improve the germination of Bidens bipinnata seeds.