• Archives of Pharmacal Research
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• v.16 no.1
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• pp.50-56
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• 1993

The microencapsulation of sodium naproxen with Eudragit. RS was studied by coacrtvation/phase separation process using Span 80 in mineral oil/acetone system. Various factors which affect the mciroencapsulation, e.g., stirring speed, and surfactant concentraction, Eudagit RS concentration and loading drug amounts were examined. For the evaluation of the prepared microcapsules, release rate, particle size distribution and surface appearance as well as in vivo test were carried out. The addition of n-hexane and freezing of microcapsules accelerated the hardening of microcapsules. The optimum concentration of Span 80 ti prepare the smallest microcapsules was the same value with the CMC of Span 80 in solvent system. When 1.5% (w/w) Span 80 was used, the smallest microcapsules were formed $(30.02\pm5.05\mu$ in diameter) belonging to the powder category showing smooth, round and uniform surface. The release of sodium naproxen was retarded by microencapsulation with Eudragit RS. The Eudragit RS microcapsules showed significantly increased AUC and MRT and deceased Cl/F in rabbits.

• Archives of Pharmacal Research
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• v.10 no.1
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• pp.42-49
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• 1987

This study is to evaluate the potential use of aclarubicin-loaded gelatin microspheres as an intravascular biodegradable drug delivery system for the regional cancer therapy. The diameter of the microspheres prepared by water in oil emulsion polymerization could be controlled by adjusting the stirring rate in the range of 10-50 $\mu$m : D(in $\mu$m) = -73.8 log (rpm) + 262.7. The addition of proteolytic enzyme increased the in vitro aclarubicin release but it did not change the amount of the initial burst release which reached about 45%. Microspheres injected intravenously into the mouse tail vein embolized only to the lung when observed by fluorescence microscopy. From histological examination following injection of gelatin microspheres into mouse femoral muscle, mild inflammation was observed from the appearance of neutrophils after 2 days and rapid repair process was confirmed thereafter. Biodegradation process of gelatin microspheres lodged on the pulmonary capillary bed was followed up by microscopic observation; degradation was taking place by about 36 hrs, followed by severe damage on the spheerical shape and microspheres was no longer found 10 days after injection.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.313-314
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• 2002

SiCp-reinforced metal matrix composites (MMCs) containing 8 wt % and 16 wt % of $SiC_p-reinforced$ with 30 and $45\;{\mu}m$ in sizes were prepared by a melt stirring-squeeze casting technique. Microstructural observation showed that particle distributions were reasonably well. Turning experiments were carried out on the composites using uncoated and triple-layer coated carbide tools at various cutting speeds under a constant feed rate and depth of cut. Coated tools indicated better performance than uncoated tools for all the materials while the poor surface finish was obtained for coated tools.

• Journal of the Korean institute of surface engineering
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• v.34 no.6
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• pp.545-552
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• 2001

Effect of ultrasonic agitation on Pd catalyst treatment was studied in metallization of ceramic boards by Cu electroless plating method.96% $Al_{2}$$O_{3}$ ceramic boards were used as substrate. In this study, the ultrasonic frequency of 28kHz was applied. In Pd catalyst, high density Pd nuclei of small size were formed during ultrasonic agitation. Density of Pd was more improved when using of ultrasonic then no stirring. In electroless plating, plating rate was in the range of 0.6~1.8$\mu\textrm{m}$/hr, which value increased with Rochelle Salts addition. Adhesion strength between ceramic boards and Cu layer was improved of 20% when using ultrasonic agitation at $30^{\circ}C$ ,5min.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.8-13
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• 2017

Analysis of quinidine for fish tissues using single drop microextraction (SDME) coupled with atmospheric pressure matrix assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) are reported. Optimization conditions; such as extraction solvent, extraction time, pH of the aqueous solution, salt additions (NaCl), stirring rate, matrix type and concentration are investigated. Linear dynamic range (${\mu}M$), limit of detection, relative recovery%, and enrichment factor are 0.08-9.2, 0.05, $94.8{\pm}3.1-98.5{\pm}3.3%$, $4.34{\pm}0.28-4.40{\pm}0.30$, respectively. SDME-AP-MALDI-MS shows good intraday and interday reproducibility.

• Tribology and Lubricants
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• v.9 no.2
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• pp.56-62
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• 1993

Al-Pb-Cu and Al-Si-Pb-Cu bearing alloys were produced by forced-stirring method and water-cooled copper mold casting to investigate the effect of the precipitation hardening on the wear properties. Sliding of produced alloy pin against a steel disc were performed under various applied loads. Lowering the wear rate and material transfer phenomena were explained by the strengthening of $\theta'$ precipitates on AI matrix. The transmission electron microscope observation reveals the role of the precipitates in the alloys with Cu. The movement of dislocations was hindered by precipitates which resulted in the reduction of plastic deformation at the worn surfaces.

• Journal of Powder Materials
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• v.9 no.5
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• pp.336-340
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• 2002

The $\alpha$-zirconium phosphate particles as fine as 20 nm were fabricated through solution technique using $ZrOCl_2{\cdot}8H_2O$ and $H_3PO_4$ as precursors. Stability of $\alpha$-Zirconium phosphate could be ensured by adding excess phosphoric acid to a stoichiometric composition Instead of using reflux route that resulted in coarsening of particles due to an inevitably long aging. The excess phosphorous incorporated in the crystal could be successfully eliminated afterwards through careful washing. Moreover, heavily agglomerated particles are observed before washing, but fairly dispersed state is found out after washing treatment. Thus, it is found that dispersed state as well as phase stability is ensured through proper washing treatment.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.853-857
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• 1995

ZrSiO4 powders were prepared from partially hydrolyzed solution of Si(OC2H5)4 and ZrOCl2.8H2O solution by the sol-gel method and formation rate of ZrSiO4 on the reaction parameter was investigated. In order to prepare homogeneous ZrSiO4 precursor gels, the H2O/Si(OC2H5)4 molar ratio of about 2, the pH of the ZrOCl2.8H2O solution fo about 4 and stirring time of the mixed solutions of about 2 hrs were appropriate. Formation of temperature of ZrSiO4 reduced about 15$0^{\circ}C$ by milling and formation of ZrSiO4 at 1300~135$0^{\circ}C$ showed an accelerative increase through the hedvall effect by silica.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.184-193
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• 2003

Cyclic sweep voltametry was performed to investigate the electrochemical behavior of heavy metal ions and the organic additives in surface finishing process. And electrolysis using parallel plate electrode electrolyzer was carried out to simulate the treatment of real waste water. Results showed that more than 99 percent of Cu was recovered and selective recovery of Cu in mixed waste water was possible, but the possibility of economical recovery of Ni and Cr were very low due to the evolution of hydrogen gas. Electrochemical oxidation of cyanide and organic additives on anode showed very excellent removal rate. The complete removal of several hundred ppm of cynide was possible within several tens minutes and organics within 2 or 3 hours. Even in case of concentrate waste water, the complete removal of COD by using NaCl and air stirring seemed to be possible.

• Particle and aerosol research
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• v.11 no.3
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• pp.77-85
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• 2015

A Belousov-Zhabotinsky reaction in a liquid-liquid system under microwave radiation was observed under non-stirring conditions. To control this non-equilibrium reaction, nano-particle, which is active under microwave irradiation, was added to the solution. Color changes of the solution during the oscillatory reaction were found to be influenced by the irradiation power although the droplet temperature was equal to the temperature of surrounding oil. During the irradiation, the period of oscillation became shorter because the reaction rate was faster. It could also be observed that there is possibility to eliminate oscillatory behaviors of the reaction using higher power of microwave. The possibility of controlling non-linear reaction using microwave was shown since microwave can easily travel through oil phase and reach water phase.