• International Journal of Concrete Structures and Materials
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• v.11 no.1
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• pp.29-43
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• 2017

This study investigates the blast resistance of fiber-reinforced cementitious composite (FRCC) panels, with fiber volume fractions of 2%, subjected to contact explosions using an emulsion explosive. A number of FRCC panels with five different fiber mixtures (i.e., micro polyvinyl alcohol fiber, micro polyethylene fiber, macro hooked-end steel fiber, micro polyvinyl alcohol fiber with macro hooked-end steel fiber, and micro polyethylene fiber with macro hooked-end steel fiber) were fabricated and tested. In addition, the blast resistance of plain panels (i.e., non-fiber-reinforced high strength concrete, and non-fiber-reinforced cementitious composites) were examined for comparison with those of the FRCC panels. The resistance of the panels to spall failure improved with the addition of micro synthetic fibers and/or macro hooked-end steel fibers as compared to those of the plain panels. The fracture energy of the FRCC panels was significantly higher than that of the plain panels, which reduced the local damage experienced by the FRCCs. The cracks on the back side of the micro synthetic fiber-reinforced panel due to contact explosions were greatly controlled compared to the macro hooked-end steel fiber-reinforced panel. However, the blast resistance of the macro hooked-end steel fiber-reinforced panel was improved by hybrid with micro synthetic fibers.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.199-204
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• 2009

Silicone dioxide absorbed polyoxyethylene alkylether sulfate (EU-S133D) surfactant was prepared. Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using Acrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We found that when Acrylate core prepared by adding 2.0 wt% EU-S133D, silicone dioxide/Acrylate core-shell polymerization was carried out on the surface of silicone dioxide particle without forming the new silicone dioxide particle during acrylate shell polymerization in the inorganic/organic core-shell polymer preparation. The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer and morphology of latex by scanning electron microscope(SEM).

• Journal of the Korean Applied Science and Technology
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• v.27 no.1
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• pp.56-60
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• 2010

Titanium dioxide particles are used as photocatalysts, sensors, adsorbents and catalyst. Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using Acrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We found that when Acrylate core prepared by adding 0.5~2.0 wt% EU-S133D, Titanium dioxide / Acrylate core-shell polymerization was carried out on the surface of Titanium dioxide particle without forming the new Titanium dioxide particle during acrylate shell polymerized in the inorganic/organic core-shell polymer preparation. The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer(TGA) and morphology of latex by scanning electron microscope(SEM).

• Journal of the Korean Ceramic Society
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• v.29 no.9
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• pp.719-728
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• 1992

ZrO2/Al2O3-Mullite composites were prepared by infiltration of the silica sol to the porous ZrO2/Al2O3 bodies. The porous ZrO2/Al2O3 bodies for infiltration were fabricated using ZrO2 (20wt%)/Al2O3 composite powders synthesized by the emulsion-hot kerosene drying method. The preparation of silica sols was conducted by the hydrolysis-peptization of an alcoholic TEOS solution. When ZrO2/Al2O3-Mullite and ZrO2/Al2O3 composites were sintered at 1$650^{\circ}C$ for 4 hrs, both of them showed an excellent sinterability. As the amount of mullite added in the composites increased, the ratio of the tetragonal phase of zirconia to the monoclinic phase at the room temperature became higher. It was known that values of the fracture toughness of the ZrO2/Al2O3-Mullite composites were about 5.48 MPa.m1/2 much larger than that of the ZrO2/Al2O3 system.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.615-621
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• 2018

Recently, various environmentally friendly products have been developed for improving the indoor air quality while pursuing a well-being nature-friendly healthy life as a core value. In this research, we not only solve the problems of existing environmentally friendly paints, but also developed a charcoal composite seats that can reduce radon, which is a natural radioactive substance, and evaluated the reduction effect of radon, formaldehyde and volatile organic compounds. In the charcoal composite seats, a sodium silicate emulsion and charcoal were mixed to prepare an charcoal liquid coating material, and the composite seats was fabricated by air-spray coating method. In order to analyze the hazardous substance reduction performance of the fabricated charcoal composite seats, radon was designed to comply with the Ministry of the Environment standard, formaldehyde and volatile organic compounds were designed to comply with KCL-FIR-1085 standard. As a result of the experiment, the fabricated charcoal composite seats was evaluated as having a radon reduction capability of about 90.8% from 20 hours, formaldehyde and volatile organic compounds were 3 hours, and the reduction capability of 96.7% and 96.6% was found respectively. It is considered that these results can be utilized as basic data at the time of product development for improvement of indoor air quality.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.76-86
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• 1998

Effects of processing variables and MAPP (maleic anhydride polypropylene) coupling agent on the properties of composite were discussed for turbulent-air-mixed woodfiber-polypropylenefiber composites. In this research, density, composition ratio, and mat moisture content were established as processing variables, and emulsified MAPP prepared by direct pressure method was incorporated as the coupling agent. And the turbulent air mixer, which was improved in function through alteration of our previous fiber mixer, was used to mix wood fibers and polypropylene fibers. At the addition level of 1% MAPP, based on oven-dried wood fiber weight, woodfiber-polypropylenefiber composites generally showed enhanced the physical and mechanical properties. And composites with low to medium densities of 0.6 to 0.8g/$cm^3$ greatly increased in these property values than with high densities of 1.0g/$cm^3$ or more by adding 1 % MAPP. Thus, MAPP addition was thought to be an effective way of enhancing properties for nonwoven web composites. At the mat moisture contents of 5 to 20%, however, the physical and mechanical properties were not enhanced by adding 1% MAPP. In the composites containing 15% polypropylene fibers, the lowest thickness swelling and water absorption values were observed at the 1% MAPP level. The addition of more than 1% MAPP had the adverse effect on the physical and mechanical properties of composites.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1295-1300
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• 1998

This study was conducted to investigate the effect of soybean protein isolate (SPI) on the baking qualities of bread which was made of composite flour blended with SPI extracted at acidic (pH 2.0, 3.0), neutral (pH 7.0) and alkaline (pH 10.0, 12.0) conditions. The mixogram showed that water absorption of composite flour dough blended with SPI extracted at pH 2.0 and 12.0 was higher than that of 100% wheat flour dough, and mixing time was shorter than that of 100% wheat flour dough. No differences were found between the composite flour blended with SPI at level of 5% and 100% wheat flour on the loaf volume of bread. The loaf volume of bread made of composite flour blended with $SPI_2\;AND\;SPI_3$ at level of 10% was lower than that of 100% wheat flour, but that of $SPI_7,\;SPI_{10},\;and\;SPI_{12}$, which had higher emulsion capacity than $SPI_2,\;SPI_3$ was similar to that of 100% wheat flour. No differences were found between the composite flour blended with SPI at level of 5% and that of 100% wheat flour on springiness, chewiness, cohesiveness, gumminess, adhesiveness and hardness of bread. The composite flour blended with SPI at level of 10% was similar to 100% wheat flour on springiness, chewiness, cohesiveness, gumminess, adhesiveness and hardness of bread except for chewiness, gumminess and hardness of $SPI_2,\;and\;SPI_{12}$ which were significantly higher than that of 100% wheat flour (P<0.05).

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.532-538
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• 2020

In this study, emulsification process were conducted to manufacture the natural sunscreen from raw materials such as shea butter, olive emulsifier wax, and green tea extract. The emulsification was optimized by using the central composite design model-response surface methodology (CCD-RSM) where the response values were established as the mean droplet size (MDS) and emulsion stability index (ESI) after 7 days in addition to UV absorbance at 300nm. The amount of emulsifier and additives and emulsification time were established as operating variables and the optimal conditions of sunscreen emulsification were accepted as 3.70, 2.47 wt.%, and 15.42 min, respectively according to the result of CCD-RSM. On the other hand, the response values were estimated as 1173.80 nm and 99.56% for MDS and ESI, respectively, after 7 days, in addition to UV absorbance at 300 nm (2.47). The average error from actual experiments was a low level as about 3.0 ± 1.5%, which is mainly due to the fact that the optimization using CCD-RSM applied in this study was in the relatively high significant level.

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.316-320
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• 2024

To optimize the emulsion stability and antibacterial activity against Escherichia coli (E. coli) of cosmeceuticals using Scutellaria baicalensis extracts and olive wax as natural emulsifiers, we conducted a study. The independent variables were the amounts of Scutellaria baicalensis extracts and olive wax added. The response variables included the emulsion stability index (ESI) of the cosmeceuticals product and the inhibition diameter against E. coli. Through central composite design-response surface methodology (CCD-RSM), we obtained a statistically significant and reliable regression equation within a 95% confidence interval. By optimizing multiple responses, we determined that the optimal emulsification conditions that satisfied both ESI and E. coli inhibition diameter were 3.7 wt% of Scutellaria baicalensis extracts and 2.7 wt% of olive wax. The predicted ESI and E. coli inhibition diameter were 97.9% and 9.7 mm, respectively. When actual experiments were conducted under the optimal conditions, the measured ESI and E. coli inhibition diameter were 95.0% and 9.4 mm, respectively, with an average error rate of 3.2 ± 0.4%.

• Macromolecular Research
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• v.15 no.4
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• pp.285-290
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• 2007

Ag nanoparticles were distributed onto polystyrene nanoparticle (PS-Ag) beads using two synthetic methodologies. In the first methodology, polystyrene (PS) beads were prepared via emulsion polymerization, with Ag nanoparticles subsequently loaded onto the surface of the PS beads. The polymerization of styrene was radiolytically induced in an ethanol (EtOH)/water medium, generating PS beads. Subsequently, Ag nanoparticles were loaded onto the PS beads via the reduction of Ag ions. The results from the morphological studies, using field emission transmission electron microscopy (FE-TEM), reveal the PS particles were spherical and nanosized, and the average size of the PS spherical particles decreased with increasing volume % of water in the polymerization medium. The size of the PS spherical particles increases with increasing radiation dose for the polymerization. Also, the amount of Ag nanoparticle loading could be increased by increasing the irradiation dose for the reduction of the Ag ions. In the second methodology, the polymerization of styrene and reduction of Ag ions were simultaneously performed by irradiating a solution containing styrene and Ag ions in an EtOH/water medium. Interestingly, the Ag nanoparticles were preferentially homogeneously distributed within the PS particles (not on the surface of the PS particles). Thus, Ag nanoparticles were distributed onto the surface of the PS particles using the first approach, but into the PS clusters of the particles via the second. The antimicrobial efficiency of a cloth coated with the Ag-PS composite nanoparticles was tested against bacteria, such as Staphylococcus aureus and Klebsiella pneumoniase, for 100 water washing cycles.