• 자원환경지질
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• 제32권4호
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• pp.373-378
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• 1999

An investigation was conducted to find out formation and is mechanism of kaolinite from pyrophyllite under hydrothermal conditions. First, a pyropyllite sample from the Heenam district, Korea, was activated by heat-treating at $400^{\circ}C$ for 3 hrs. The kaolinite powder was successfully obtained by subjecting the dried feedstock to autoclaving at $200^{\circ}C$, 15atm, pH<1 for 5days with addition of 17.4mol/l $AlCl_3$. Evidently, the $AlCl_3$ addition as a mineralizer strongly promoted incorporation of $Al^{3+}$ ion into pyrophyllite structure which was subdequently converted into kaolinite. It also indicated that the formation of octahedral feed solution. The final pH of the solution was decreased to ~0.3. The transformation reaction was not noticeably accelerated when 10wt% natural kaolinite was added as the seeds, suggesting that the transformation was not reconstructional, but substitutional type.

• 자원환경지질
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• 제33권6호
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• pp.519-524
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• 2000

This study has been performed to evaluate the possibility of utilizing stone powder sludges from stone quarry and manufacturing plant as adsorbents for heavy metals in industrial wastewater. The stone powder sludges from stone quarry (IS-01) have the most effective adsorption capacity (above 95％ of initial concentrations) under the given experimental conditions of reaction times (Pb : 15 min, Cu : 2 hr, Zn : 48 hr), initial acidity of solution (pH>3) and dosage (sludge/liquid ratio : 0.02). The stone powder sludges from manufacturing plant (CW-01) show relatively high adsorption capacity (about 95％ of initial concentrations) only for Pb with a reaction times of 12 hours, initial acidity of solution (pH>3) and dosage (sludge/liquid ratio : 0.02). The stone powder sludges (IS-01) from stone quarry having relatively excellent adsorption capacity under the given experimental conditions show their potential utilization as heavy metal adsorbents.

• 대한약침학회지
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• 제5권2호
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• pp.116-119
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• 2002

Objective : This study was designed to show the possible functional groups from the herb medicine in boiling water. Results : The results are summarized as follows: 1. the new functional groups can be synthesized in water solution for herb medicine. 2. The boiling water solution may change the poison materials into harmless materials. 3. The multiplication, the offset, the contradiction, etc. in terms of mixed herb medicine can be explainable by these reactions. 4. After finding the new medicinal substances for the specific disease, we can synthesize, modify, and mass produce those for that disease.

• Macromolecular Research
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• 제11권6호
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• pp.495-500
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• 2003

UV-induced graft polymerization of glycidyl methacrylate (GMA) to a polypropylene (PP) membrane was carried out in the vapor phase with benzophenone (BP) as a photoinitiator. Attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM) were utilized to characterize the copolymer. The degree of grafting increased with increasing reaction time, increased UV irradiation source intensity, and increased immersion concentration of the BP solution. The optimum synthetic condition for the PP-g-GMA membrane was obtained with a reaction time of 2 hrs, a UV irradiation source intensity of 450 W, and an immersion concentration of the BP solution of 0.5 mol/L. The pure water flux decreased upon increasing the degree of grafting and increasing the amount of diethylamino functional group introduced. The analysis of AFM and SEM images shows that the graft chains and diethylamino groups of PP-g-GMA grew on the PP membrane surface, resulting in a change in surface morphology.

• 생약학회지
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• 제15권3호
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• pp.134-138
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• 1984

In this study the solubility of cholesterol was examined with ginseng saponin and chemical saponin used in the preparation of reaction mixture of 0.15M NaCl solution. It was shown that the solubility of cholesterol varied in the concentration of ginseng saponins and in the temperature and that the osmotic pressure and the surface tension was amenable to changes in the concentration of ginseng saponins and the incubation period of the reaction mixture. From the results, it was revealed that the solubility of cholesterol was dependent upon the incubated times and the concentration of ginseng saponins in 0.15mM NaCl solution and that ginseng saponins have the cholesterol solubilizing effect as evidenced in the physicochemical properties of mixed micelle formation and surface-activity.

• 한국분말재료학회지
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• 제18권1호
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• pp.73-77
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• 2011

$Y(OH)_3$ nanowires were synthesized by a hydrothermal reaction of metallic Y with aqueous solution of LiOH. The morphology and the size of the nanowires changed with varying the volume of the LiOH solution inside the autoclave. $Y(OH)_3$ nanowires transformed to $Y_2O_3$ by a subsequent heat-treatment without morphological change. By a proper control of hydrothermal reaction parameter and heat-treatment, the yield of pure $Y_2O_3$ nanowires up to 97% was attained.

• 한국세라믹학회지
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• 제34권11호
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• pp.1159-1164
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• 1997

Magnetite(Fe3O4) powders were synthesized through glycothermal reaction by using crystalline $\alpha$-FeOOH as precursor and ethyleanne glycol as solvent. The phase, morphology and particle size of synthesized powders were characterized by XRD and an SEM. When only ethylene glycol was used as solvent, the phase was transformed from $\alpha$-FeOOH to $\alpha$-Fe2O3 and finally Fe3O4 at 27$0^{\circ}C$ for 6hr without morphological change. But by addition of water, Fe3O4 powders were synthesized at 23$0^{\circ}C$ for 3hr through solution-recrystalization process. As the content of water addition increased, the particle shape changed from sphere to octahedron and the partcle size increased. When the excess amount of water added, residual $\alpha$-FeOOH or $\alpha$-Fe2O3 was recrystalized.

• KSBB Journal
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• 제9권1호
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• pp.63-71
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• 1994

During the last decade enzyme reaction in organic solvent has been studied to show that specificity in buffer is different from that in organic solvent. The specificity of restriction enzyme was effected by various factors such as ionic strength, salt organic solvent and temperature. In this study, restriction enzyme PvuII which is used most frequently in genetic engineering and the substrate was vector pGEM3 whose sequence was already known were used. As a result the recognition sequence site was changed in the presence of organic solvents whose Log P are -1.5∼0. Their specificities were contrast with activities were contrasted. Specificities were not changed in organic solvent easily in inactivating enzyme. We think that the enzyme recognition site was not changed randomly but by preferential order. A recombinant vector which does not contain typical cleavage site CAG↓CTG was cleaved in 20% ethanol solution. This result might show that restriction enzyme could be used to cleave at unusual sites by changing the reaction conditions.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.41-42
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• 2011

The purpose of this study is not only fixation of carbon dioxide using the cement-saturated solution by wet carbonating reaction but also evaluate the possibility of storage technology of Carbon dioxide. wet carbonation is reaction of CO₂ injection by CO₂ reactor. As a result of experiment, the carbon dioxide is fixed, and high-purity Calcium Carbonate is eluted.

• Journal of Electrochemical Science and Technology
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• 제7권1호
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• pp.27-32
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• 2016

Although the time dependences of the electrocatalytic activities of Pt and Pd nanoparticles during electrochemical operations have been widely studied, the time dependences under nonpolarized conditions have never been investigated in depth. This study reports the changes in the electrocatalytic activities of Pt and Pd nanoparticles with aging in air and in solution. Pt (or Pd) nanoparticle-modified electrodes are obtained by adsorbing citrate-stabilized Pt (or Pd) nanoparticles on amine-modified indium-tin oxide (ITO) electrodes, or by electrodeposition of Pt (or Pd) nanoparticles on ITO electrodes. The electrocatalytic activities of freshly prepared Pt and Pd nanoparticles in the oxygen reduction reaction slowly decrease with aging. The electrocatalytic activities decrease more slowly in solution than in air. An increase in surface contamination may cause electrocatalytic deactivation during aging. The electrocatalytic activities of long-aged Pt (or Pd) nanoparticles are significantly enhanced and recovered by NaBH₄ treatment.