• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.619-624
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• 2003

The $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ (x=0.02, 0.05, 0.08, and 0.12) powders (${\thickapprox}1{\mu}m$) synthesized by sol-gel method, whose surfaces are modified in a colloidal silica suspension (size of $SiO_2$ particles: ${\sim}30$ nm), have been fabricated to highly stable and effective luminescent films on the glass substrates. Thanks to the fused $SiO_2$ nano particles in the vicinity of the glass softening temperature (at around $700^{\circ}C$), $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ powders are strongly attached onto the surface of glass substrate (>9H, pencil hardness tester). This simple and low-cost method to get $Gd_{1.9-x}Li_{0.1}Eu_xO_3$ phosphor films without any loss of luminescence brightness would promise for applications to display devices.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.456-462
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• 1992

This study was performed to rapid fermentation from sardine hydrolyzate by using column reactor. The column reactor was constructed from three glass columns $(30cm{\times}5cm)$ and each column was packed with colloidal silica and sodium alginate (1:5) on which Pediococcus halophilus R-22, Saccharomyces rouxii R-60 and Candida etchellsii H-50, respectively, was previously fixed. At that time, optimal conditions for rapid fermentation were found the pH of 5.2, temperature of $30^{\circ}C$ and 10% NaCl. For rapid fermentation, immobilized whole cells of P. halophilus R-22, S. ruoxii R-60 and C. etchellsii H-50 packed the each column reactor were produced 0.75% lactic acid, 2.5% ethylalcohol and 18 mg/l 4-ethylguaiacol under the optimal conditions.

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.285-292
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• 2005

Anti-reflection film was coated by using spherical silica nano colloids. Silica colloid sol was reserved between two inclined slide glasses by capillary force, and particles were convectively stacked to form a film onto the substrate as the water evaporates. As the sliding speed increased, the thickness of the film decreased and the wavelength at the maximum transmittance decreased. The microstructure observed by SEM showed that silica particles were nearly close packed, which enabled the calculation of the effective refractive index of the film. The film thickness was measured by proffer and calculated from the wavelength of maximum transmittance and the effective refractive index. The effective refractive index of the film could be controlled by a subtle controlling of the coating speed and by mixing two different sized silica particles. When the 100 nm and 50 m particles were mixed at 4:1-5:1 volume ratio, the maximum transmittance of $95.2\%$ for one-sided coating was obtained. This is the one that has increased by $3.8\%$ compared to bare glass substrate, and shows that $99.0\%$ of transmittance or $1.0\%$ of reflectance can be achieved by the simple process if both sides of the substrate are coated.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.396-396
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• 2009

Chalcopyrite semiconductor $CuInSe_2$ nanoparticles were prepared using a low temperature colloidal route by reacting the starting materials (CuI, $InI_3$ and $Na_2Se$) in solvents. After synthesised $CuInSe_2$ nanoparticles precursors were mixed with organic binder for the viscosity of the precursor slurry to be suitable for the doctor blade method. The mixture of $CuInSe_2$ and binder was deposited onto molybdenum-coated sodalime glass substrates to form thin film. The precursor thin films were preheated on the hot plate to remove remaining solvents and binder material. After subsequent thermal processing of the thin film under a selenium ambient, $CuInSe_2$ absorber layer with grain size significantly lager than that of the nanoparticles was formed.

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.1064-1072
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• 1996

The synthetic conditions and characteristics of ZSM-5 type zeolites (ZSM-5/silicalite) for the preparation of the zeolite composite membranes for gas separation were investigated. ZSM-5 zeolites could be synthesized by the hydrothermal treatment of the mixture of colloidal silica sol aluminum nitrate sodium hydroxide and TPABr at a temperature range of 150-17$0^{\circ}C$ in the autoclave. Silicalties were done from the solution of water glass water and TPABr. Their crystalline structures transformed from orthorhombic to monoclinic from and their pore structures of three-dimensional channels were opened as TPABr filling channels was burned off at the calcination temperature of 50$0^{\circ}C$. The specific surface area of the calcined zeolite was about 360 m3/g and its surface property was hydrophobic. Crystal sizes of ZSM-5 and silicalite were 0.5-1.0${\mu}{\textrm}{m}$ and 8-10${\mu}{\textrm}{m}$ respectively having no change due to the calcination. In particular the shape and the size of the ZSM-5 type zeolite were sensitively varied with silica sources and concentrations of reaction solutions/sols.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.542-548
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• 2012

The viscosity of a ceramic slurry depends on the slurry concentration, particle shape and size, hydrodynamic interactions, temperature, shear rate, pre-treatment condition and the method of measurement with the selected equipment. Representative ceramic slurries with low to high viscosity levels are selected from colloidal silica, barium titanate slurry and glass frit paste. Rotational rheometers and vibrational viscometers are used to compare the measured viscosity for various ceramic slurries. The rotational rheometer measured the viscosity according to the change of the shear rate or the rotational speed. On the other hand, the vibrational viscometer measured one point of the viscosity in a fixed vibrational mode. The rotational rheometer allows the measurement of the viscosity of a ceramic paste with a viscosity higher than 100,000 cP, while the vibrational viscometer provides an easy and quick method to measure the viscosity without deformation of the ceramic slurry due to the measurement method. It is necessary to select suitable equipment with which to measure the viscosity depending on the purpose of the measurement.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1930-1932
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• 2005

Colloidal Silica(CS)/methyltrimethoxy silane(MTMS) and CS/MTMS/epoxy silane(Es) sol solutions were prepared in variation with synthesizing parameters such as kinds of CS, kinds of silane and reaction time. In order to understand its physical and chemical properties, sol-gel coating films on glass were fabricated. In the case of CS/MTMS sol, the coating films had high contact angle and more enhanced flat surface than those in the case of CS/MTMS/ES sol. Also, the coating films obtained from single CS had a better flat surface than those obtained from mixed CS. In the case of thermal stability, thermal dissociation of CS/MTMS and CS/MTMS/ES sol-gel coating films did not occur up to $550^{\circ}C$ and $440^{\circ}C$ respectively. The thickness of coating films obtained from CS/MTMS sol increased than those of CS/MTMS/ES sol. In addition, the coating films obtained from single CS were more thicker than those obtained from mixed CS.

• The Korean Journal of Cytopathology
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• v.7 no.2
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• pp.111-121
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• 1996

Fine needle aspiration cytology(FNAC) is preferred because of simplicity, safety, and reliability in the evaluation of patients with thyroid nodule or hyperplasia. However, there are a few limitations such as false-negative or false-positive cases and non-diagnostic material. To evaluate the usefulness of FNAC in thyroid lesions, we reviewed 704 FNAC cases of thyroid nodules from 1988 to 1994 at Soonchunhyang University Hospital. The results are as follows. 1. Among 704 FNAC cases of thyroid gland, 571(81.1%) cases were benign, 12(1.7%) were suspicious, 71(10.1%) were malignancy, and 50(7.1%) were material insufficiency. The cytologic diagnoses of the benign lesions included 168 cases of follicular neoplasm, 139 cases of adenomatous goiter, 162 cases of follicular lesion such as follicular neoplasm or adenomatous goiter, 61 cases of Hashimoto's thyroiditis, 13 cases of subacute thyroiditis, and 28 cases of colloidal nodule or benign nodule. The malignant lesions included 68 cases of papillary carcinona, two medullary carcinomas and a case of metastatic colon cancer. 2. The average number of cytologic smear slides was $4.12{\pm}1.81$ in material insufficiency and $5.63{\pm}1.79$ in diagnostic cases. This difference was statistically significant(p<0.00001). 3. Histological assessment of 150 cases revealed 2 false negative and 1 false positive cases. The false negative cases were a case of marked sclerosis in papillary carcinoma and an occult case of papillary carcinoma. The false positive case resulted from pseudo-ground glass nuclei due to marked dry artifact. 4. Comparison between the FNAC and the histologic diagnosis revealed that FNAC had a sensitivity of 93.5%, a specificity of 99.2%, a false negative rate of 6.6%, a false positive rate of 0.8%, and an overall diagnostic accuracy of 98.0%. Therefore, FNAC of thyroid gland is a very reliable diagnostic method with excellent accuracy rate.

• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.766-770
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• 2004

High-transmittance film was coated by using spherical silica nano colloids. Silica colloid sol was preservred between two inclined slide glasses by capillary force, and particles were stacked to form a film onto the substrate as the upper glass was sliding. As the sliding speed increased, the thickness of the film decreased and light transmittance varied. The microstructure observed by SEM showed that silica particles were nearly close packed, which enabled the calculation of the effective refractive index of the film. The film thickness calculated from the wavelength of maximum transmittance and the effective refractive index was well coincided with the thickness observed by SEM and measured by profiler. The maximum transmittance of $94.7\%$ was obtained. This means that $97.4\%$ of transmittance or $1.3\%$ of reflectance can be achieved by simple process if both sides of the substrate are coated.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.417-429
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• 2018

Background: The objective of this study was to make colloidal dispersions of the active compounds of radix of Angelica gigas Nakai that could be charaterized as nano-composites using hot melt extrusion (HME). Food grade hydrophilic polymer matrices were used to disperse these compound in aqueous media. Methods and Results: Extrudate solid formulations (ESFs) mediated by various HPMCs (hydroxypropyl methylcelluloses) and Na-Alg polymers made from ultrafine powder of the radix of Angelica gigas Nakai were developed through a physical crosslink method (HME) using an ionization agent (treatment with acetic acid) and different food grade polymers [HPMCs, such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in the HP55-mediated extrudate solid formulation (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (${\Delta}H=10.62J/g$) of glass transition temperature (Tg) in the HP55-ESF than in the other formulations. Infrared fourier transform spectroscopy (FT-IR) revealed that new functional groups were produced in the HP55-ESF. The content of phenolic compounds, flavonoid (including decursin and decursinol angelate) content, and antioxidant activity increased by 5, 10, and 2 times in the HP55-ESF, respectively. The production of water soluble (61.5%) nano-sized (323 nm) particles was achieved in the HP55-ESF. Conclusions: Nano-composites were developed herein utilizing melt-extruded solid dispersion technology, including food grade polymer enhanced nano dispersion (< 500 nm) of active compounds from the radix of Angelica gigas Nakai with enhanced solubility and bioavailability. These nano-composites of the radix of Angelica gigas Nakai can be developed and marketed as products with high therapeutic performance.