• Korean Journal of Microbiology
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• v.11 no.4
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• pp.189-195
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• 1973

With the gradual expansion of copper demands, the utilization of enormous tonnages of waste copper mineral containig up to 0.5% copper becomes available. In order to investigate the possibilities on the application of bacterial leaching method to waste dumps or abandoned mines, the authors had carried out microbial leaching of copper minerals by F.ferrooxidans isolated from the Dalsung copper mine water. The results obtained were as follows : 1. The copper extraction rate from the Dalsung chalcopyrite has been a little accerelated by using flasks in place of percolators. 2. The percentage of copper extracted from the Dalsung chalcopyrite sample was 100% in 30 days in the presence of iron-oxidizing bacteria F.ferrooxidans while 9.27% in the absence of bacteria. 3. F.ferroxidans was capable of producing sufficient quantities of ferric sulfate and sulfuric acid from ferrous iron to bring about the dissolution of 100% of copper from the Dalsung chalcopyrite.

• Journal of Pharmaceutical Investigation
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• v.29 no.1
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• pp.1-5
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• 1999

The bioavailabilities of baicalin in water, oil, w/o and o/w emulsion were evaluated in rats. The dissolution rate of baicalin in o/w emulsion was smaller than those of w/o form in dilute hydrochloric acid solution (pH 1.2) and in PBS (pH 6.8). The absorption rate of baicalin from w/o emulsion was smaller than that of o/w emulsion in the different parts of rat intestine of the rats. Following oral administration in rats, the $C_{max}$ of baicalin from water phase, oil phase, o/w wand w/o emulsion were 2.11, 0.61, 1.57, and $1.35\;{\mu}g/ml$, respectively. The relative bioavailability of w/o emusion was 129 % when it was compared with water phase. This result suggests that the improvement of bioavailability for baicalin in w/o emulsion might be practically available.

• Journal of Powder Materials
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• v.21 no.2
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• pp.114-118
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• 2014

In this study, an aluminum oxide layer for sealing treatment of nano-diamond powder was synthesized by anodizing under constant current. The produced pore size and oxide thickness were investigated using scanning electron microscopy. The pore size increased as the treatment time increased, current density increased, sulfuric acid concentration decreased, which is different from the results under constant voltage, due to a dissolution of the oxide layers. The oxide layer thickness by the anodizing increased as temperature, time, and current density increased. The results of this study can be applied to optimize the sealing treatment process of nano-diamond particles of 4-10 nm to enhance the resistances of corrosion and wear of the matrix.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.1
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• pp.33-37
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• 2001

Kaolinite was synthesized through th acid treatment of mixture which consisted of psudoboehmite and colloidal silica in hydrothermal reaction at $213^{\circ}C$ under autogeneous vapor pressure. Crystallization process was characterized by X-ray powder diffraction pattern, IR spectra and Hinckley index was calculated. The synthesis in acidic solution promotes the dissolution of the starting materials and leads to crystallization of kaolinite. The rate of crystallization to kaolinite and stacking defect were found to e affected by kind of anion, acidity and starting materials.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.21-26
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• 2007

The concentrations of fourteen mineral and trace elements (Al, Ca, Fe, K, Mg, Se, Ba, Co, Cu, V, Pb, Hg, Cd and As) were determined in Ganoderma Lucidum and their infusions consumed for medical purposes collected from Vietnam, China and some places in Korea. Concentrated acid digestion procedure was applied under optimized conditions for dissolution of these medicinal fungi. Element concentrations in these fungi and their in-fusions were then determined by ICP-AES. The mineral and trace element content of these samples and their in-fusions showed a wide variability However, distribution of some elements in the infusions is not high.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.71-75
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• 2001

The first step for recycling the CRT bulb is to remove frist seals between the panel and funnel. For this purpose, various kinds of methods have been used. One of those is to use the nitric acid, which is a proven technology and widely used in CRT-making industries. The process. however. has a problem of NOx generation. Such a drawback can be overcome by using a new chemical. This new chemical can remove the frit without NOx generation. This paper describes the dissolution ability of the chemical for lead and zinc oxides and the application to the separation of the CRT panel from its funnel.

• Journal of Surface Science and Engineering
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• v.30 no.1
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• pp.44-56
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• 1997

Influence of electrochemical etching conditions on capacitance gain of aluminium electrolytic on capacitor foil has been investigated by etching cubic textured high purity aluminum foil in dilute hydrochloric acid. Uniformly distributed etch pit tunnels on aluminum surface have been obtained by pretreatment aluminium foil in 10% NaOH solution for 5 minutes followed by electrochemical etching. Electrostatic capacitance of etched aluminium foil anodized to high voltage increased with the increase of current density, total charge, temperature and concentration of electrolyte up to maximum CV-value and then deceased. Election optical observation of the etched foil revealed that the density of etch of etch pits increased with the increase of current density and concentration of electrolyte. this increase of etch pit density enlarged of the increase of capacitance. However, abnormal high current density and high electrolyte concentration induced the local dissolution of the foil surface which resulted the decrease of foil capacitance.

• Journal of Pharmaceutical Investigation
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• v.9 no.1
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• pp.15-19
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• 1979

The absorption rate of lysino-methylene-ampicillin from the rat small intestine, compared with ampicillin, was determined in vitro and in situ to establish the biopharmaceutical properties of lysino-methylene-ampicillin which is one of the new penicillinase-resistance antibiotics. The half of administered dose was absorbed rapidly within thirty minutes. The water-oil distribution coefficient of lysino-methylene-ampicillin was 0.03 in chloroform versus buffer system with $Na_{2}HPO_{4}-citric$ acid of pH5.2 at $37^{\circ}C$, and its dissolution rate reached the plateau in an hour and then represented 0.6 percent of equilibrium solubility

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.101-110
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• 1987

In order to reduce gastric irritation in the stomach of iron preparations, ferroglycine fumarate (FGF) granules coated with hydroxyethylcellulose was made by matrix granulator, and the constrained optimization method, employing the Lagrange equation, was successfully applied to the manufacturing process design of controlled release tablets. The effects of stearic acid and dried corn starch on tablet hardness, friability, dissolution rate $t_{50%}$ and tablet volume were found to be very significant. In rabbit test, pharmacokinetic parameters $(K_a,\;C_{max}\;and\;AUC^{0-12})$ and urinary excretion rate $(K_e)$ of the controlled release FGF tablets were higher than those of controlled release ferroglycine sulfate tablets which were manufactured in the same optimal conditions. Controlled release FGF tablets were more stable than controlled release ferroglycine sulfate tablets in accelerated storage conditions.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.186-188
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• 1963

An attempt to improve the method of volumetric determination of tungsten developed by Luke has been made successfully. Using amalgam coated lead instead of pure metallic lead in the reduction procedure. W(VI)-W(III) reduction has been found to be quantitative in rather concentrated hydrochloric acid. Since there was no excessive dissolution of lead via reduction of hydrogen ion, lead surface was totally accessible for the reduction of tungsten and no trouble was caused by dereposition of $PbCl_2$ crystals at the nozzle of Jones reductor. Furthermore, it has been confirmed that almost 100 mg. of $WO_3$ can be handled easily if the chloride concentration of the HCl is increased by adding solid $NH_4Cl$.