• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.5
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• pp.241-245
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• 2013

Granular bamboo-derived active carbons (AC) were impregnated (or coated) with $TiO_2$ nano crystalline powders. The photocatalytic activity of the $TiO_2$-impregnated active carbons ($TiO_2$/AC) were determined on the basis of the degradation rate of methylene-blue aqueous solution under UV irradiation. The active compounds of $TiO_2$ were impregnated onto the AC under moderate hydrothermal conditions (${\leq}200^{\circ}C$, pH 11). The mean size of $TiO_2$ particles calculated from BET surface area were found to be as 50 nm. The $TiO_2$ precipitates were coated on the cavities or pores on the surfaces of highly activated carbons. Since the hydrothermal process led to a lowering of the on-set temperature of the anatase-to-rutile transition of $TiO_2$ as low as $200^{\circ}C$, $TiO_2$ crystallites of a pure anatase or a mixed form with rutile were successfully coated on the AC depending on the synthesis temperatures.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.854-862
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• 2016

As the demand for a clean energy to replace fossil fuel being depleted increases, hydrogen energy is considered as a promising candidate for future energy source. Water electrolysis which produces hydrogen has high energy efficiency and stability but still has a large overpotential for oxygen evolution reaction (OER). In this study, $Co_3O_4$ catalysts with different morphology were prepared by spray pyrolysis from solutions which contain Co precursor and various organic additives (urea, sucrose, and citric acid), followed by post heat treatment. For the catalysts synthesized, X-ray diffraction (XRD) measurements were performed to identify their crystal structure. Morphology and surface shape of the catalysts were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Surface area and pore volume were examined by nitrogen adsortpion & desorption tests and X-ray photoelectron spectroscopy (XPS) was conducted to confirm nitrogen doping. Linear sweep voltammetry (LSV) was carried out to investigate OER activity of $Co_3O_4$ catalysts. As a result, bare-$Co_3O_4$ which has high surface area and small particle size determined by spray pyrolysis showed high activity toward OER.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.3-9
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• 2013

In ultra high strength concrete, when electric arc furnace oxidizing slag is substituted for sea sand as fine aggregate, compressive strength was improved about 15 MPa. To figure out the cause of the improvement in compressive strength, this study considered the dissolution characteristics of Ca component in fine aggregate and examined the microstructure, porosity, microhardness, and Ca/Si mole ratio on the interface of fine aggregate and paste. And to examine the mechanism of strength improvement resulted from the shape of fine aggregate, this study measured the surface roughness of fine aggregate with AFM. According to the result of this experiment, the mechanisms of strength improvement in ultra high strength concrete resulted from the use of electric arc furnace oxidizing slag as fine aggregate can be divided into chemical and physical mechanisms. In the chemical mechanism, the soluble Ca component contained in electric arc furnace oxidizing slag is dissolved and forms a hydrate between fine aggregate and paste to improve the interlocking strength of fine aggregate-paste. Also, it makes the microstructure around the fine aggregate. And in the physical mechanism, electric arc furnace oxidizing slag has a twice greater surface roughness than sea sand, so the interlocking strength between fine aggregate and paste increases, which contributes to the development of compressive strength.

• Composites Research
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• v.29 no.4
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• pp.216-222
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• 2016

Ring-opening metathesis polymerization of p-dicyclopentadiene (DCPD) can be performed using the tungsten type catalyst. This reaction usually progresses in nitrogen condition, because the catalysts are extremely sensitive in air condition. To solve this problem, DCPD resin with tungsten (W) was cured using hot press after stirring of DCPD A and B liquid in air condition. Mechanical properties of DCPD were improved by reducing microvoid occurrence successfully by using hot press method. It might be because hot press could provide sufficient press on DCPD specimen. Addition of catalyst was not effective for the curing of resin in a short time. During polymerization, pressure and temperature had a great influence on the mechanical properties of DCPD.

• Journal of Plant Biotechnology
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• v.35 no.1
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• pp.55-61
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• 2008

Previous studies on genetic transformation of chrysanthemum using cold regulated gene (BN115) have been conducted and the PCR and Real-Time PCR based method to determine the presence of the transferred cold regulated gene in the chrysanthemum was established. To check whether over-expression of BN115 gene in transgenic chrysanthemum will enhance their tolerance to cold stress, the transgenic chrysanthemum were grown under low temperature condition and several cold signalling including growth characteristics, stoma size and shape, SPAD value and ion leakage test were investigated. The transgenic chrysanthemum in the low temperature growth chamber grow much faster in term of the height, number and size of the leaves than those of wild-type plants and damage of transgenic plant caused by the low temperature was much less than that of wild-type plants. The stoma type and size of transgenic plant leaves grown at $5^{\circ}C$ were much similar to of wild-type plant cultured on $25^{\circ}C$ It has been found that SPAD value of transgenic plants was much higher than those of wild-type, but the EC density being lower under low temperature condition.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.515-521
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• 2018

This was carried out to develop a chromosome-doubled (12x) persimmon that will be used as a crossing parent to select seedless persimmon cultivars with the change of the consumption trend recently. To obtain a chromosome-doubled (12x) persimmon, colchicine was applied at the meristem of seedlings in vitro derived from cross among hexaploid persimmon (Diopyros kaki Thunb.). These were treated with 0.03%, 0.05% and 0.1% colchicine respectively for doubling chromosome, and it was most effective at the concentration of 0.05% colchicine. After colchicine treatment, we conducted tests to elucidate conditions for inducing shoot and root development. As the result, the shoots grew best when cultivated at 1/2MS media plus 10 and $30{\mu}M$ zeatin respectively, and the roots grew best when cultivated at 1/2MS media after dipping for 5 seconds at 10 mM NAA+5% DMSO. We also compared seedlings that have chromosome (6x) do not doubled and crossing parents (6x) and chromosome-doubled seedlings (12x). As the result, these chromosome-doubled seedlings (12x) showed lower stomatal density and larger stomatal size.

• Journal of Dairy Science and Biotechnology
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• v.31 no.1
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• pp.85-91
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• 2013

In this study, the effects of adding cheese in the manufacture of rice cakes having 5 different vegetable-derived natural coloring materials were investigated with respect to quality characteristics during storage. Rice cake samples were prepared without (control) or with the addition of 2.0%, 3.0%, or 4.0% cheese. Changes in pH, external appearance, total solid content, and scanning electron microscopy (SEM), texture and sensory characteristics were monitored during storage. The sensory and texture characteristics of the rice cakes with cheese were investigated with respect to color, flavor, and overall acceptability. The total solid content and pH of the cheese-treated rice cakes were higher than that of the control during storage. Rice cakes added with cheese had higher liquid flavor than control. Results revealed that rice cakes added with cheese at less than 4% addition had the best taste, appearance, and sensory properties. Moreover, the addition of cheese to five-colored rice cakes provides additional nutrients while maintaining flavor and quality.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.80-86
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• 2009

In this study, binderless zeolite BaX granule, an effective adsorbent for the separation of p-xylene was made. This adsorbent which has a sufficient strength, high specific surface area and selectivity to p-xylene was prepared by various steps, such as granulation process, calcination, binderless treatment, ion-exchange, and activation. In the granulation, the concentration of colloidal silica solution was controlled in order to confirm the effect of $SiO_2$ contents after binderless treatment. As a result, we confirmed that the compressive strength of granule after binderless treatment was increasing with increasing proportion of $SiO_2$ in the granule. And then Na-ion in granule was exchanged with Ba-ion by successive batch ion-exchange process. And then prepared adsorbents were tested for p-xylene separation by batch adsorption at $90^{\circ}C$. As a results of batch adsortion test, we confirmed that prepared adsorbents have a high selectivity to p-xylene. Also, it could be conformed that the prepared binderless zeolite BaX has a sufficient compressive strength (0.450 kgf), high specific surface area $(647.57m^2/g)$, high crystallinity (98.5% compared with zeolite NaX powder), and selectivity to p-xylene.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.720-725
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• 2017

M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm) catalysts were prepared for the partial oxidation of methane (POM) to syngas. The catalysts were characterized by BET, TEM, and XPS. The BET-specific surface area and average pore size for M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm) were 538.8, 504.3, and $447.3m^2/g$ and 6.4, 6.8, and 7.1 nm, respectively. TEM results showed that the mesoporous hexagonol structure was formed for SBA-15, while the homogeneous dispersion of Ni and Ce particles on the surface was formed for Ce(10)-Ni(5)/SBA-15 caused by the confinment effect of SBA-15. XPS data confirmed that $Ce^{4+}$ and $Ce^{3+}$ on the surface catalyst have two oxidation states due to the lattice oxygen species ($O^{2-}$, $O^-$). The yields of POM to syngas over Ce(10)-Ni(5)/SBA-15 were 52.9% $H_2$ and 21.7% CO at 1 atm, 973 K, $CH_4/O_2=2$, $GHSV=1.08{\times}10^5mL/g_{cat.}{\cdot}h$, and these values were kept constant even after 75 h on streams. The same tendency of syngas yields was observed for M(10)-Ni(5)/SBA-15(M=Ce, Nd, Sm). These results confirm that the redox reaction of promoters including Ce, Nd, and Sm enhanced the stability and yield of catalysts.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.166-170
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• 2000

This study was conducted in to elucidate the changes of growth characteristics and photosynthesis in three soybean (Glycine max L. cv. Danwonkong, Hwangkeumkong and Kwangankong) 30 day old seedlings to 100mM NaCl concentration containing 1/2 Hoagland's nutrient solution in sand culture. The main stem height and number of main stem node were decreased. thus, leaf area and dry matter were decreased with 100mM NaCl. Growth reduction was less little in Hwangkeumkong than other cultivars. The stem growth rate was affected less than other parts as root or leaf, by NaCl treatment. The specific leaf area (SLA), shoot : root ratio and leaf : root ratio decreased with NaCl solution except for those of Hwangkeumkong. There is no general tendency in leaf thickness by leaf position of three cultivars. The chlorophyll content (SPAD) of the primary and 2nd leaf slightly decreased under NaCl solution but rapidly increased in non-NaCl solution at 15 days after treatments. The photosynthesis, stomatal conductance and transpiration of 2nd leaf positions reduced by NaCl and there were a sigificant correlation between photosynthesis and stomatal conductance or transpiration.