• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.591-600
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• 2018

The use of genetically modified (GM) crops has increased continuously over the world, and concerns about the potential risks of GM crops have also risen. Although, until now, GM crops have not been cultivated commercially in Korea, it is necessary to develop technology for the safe evaluation of GM crops. In this study, we investigated the influence of gene flow from GM to non-GM soybeans by the size of the pollen donor. In the experimental design, GM soybeans were placed in the center as a pollen donor and non-GM soybeans were placed in four directions as the pollen receivers. Three sizes of pollen donor were designed as $90cm{\times}90cm$, $180cm{\times}180cm$, and $360cm{\times}360cm$. A total 22,719 seeds were collected from non-GM soybeans, and 14 hybrids were finally obtained through herbicide resistance screening and PCR analysis. The highest hybridization rate was 0.78% at a distance of 15 cm from a $360cm{\times}360cm$ GM pollen donor, and the farthest distance of hybridization was 180 cm from a GM pollen donor which was $360cm{\times}360cm$ in size. Ten hybrids were found among the 14 hybrids at the $360cm{\times}360cm$ pollen donor size, 3 hybrids at $180cm{\times}180cm$, 1 hybrid at $90cm{\times}90cm$. From these results, it could be concluded that with the larger pollen donor size, more hybridization occurred in soybeans.

• Analytical Science and Technology
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• v.21 no.1
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• pp.20-24
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• 2008

A chemiluminescence method has been developed to determine vitamin $P_1$ in aqueous solution which is based on the enhancement of the intensity of lucigenin using lucigenin-$H_2O_2$ as chemiluminogenic system. The effects of experimental parameters such as concentrations of lucigenin, pH and concentrations of $H_2O_2$ were studied. The present method allows the determination of vitamin $P_1$ over the range $7.5{\times}10^{-6}{\sim}5.0{\times}10^{-4}mol/L$. The detection limit was $5.7{\times}10^{-7}mol/L$. The relative standard deviation was 0.75 % for 10 determinations of $7.5{\times}10^{-5}mol/L$ vitamin $P_1$. The correlation coefficient of the working curve was 0.9984 (S/N=3).

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.3
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• pp.84-92
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• 2008

This study is to investigate the flexural performance of Near Surface Mounted (NSM) strengthening method using Fiber reinforced Polymer (FRP) materials to concrete structures. For this study, the inverse-shaped trapezoid CFRP composite material which has been registered as New Excellent Technology (NET) 351 was adopted to the concrete structure. In this study, two types of the CFRP types were considered; Type A ($15{\times}13{\times}6mm$) and Type B ($4{\times}3{\times}10mm$) with different strengthening ratio. In the result of the test, it was proved that NSM strengthened specimens had more flexural performance of 20-100% than that of the unstrengthened specimen. With this test result, the structural efficiency was investigated based on the coefficient of ductility and coefficient of crack resistance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.228-238
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds (175.8mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves (72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.411-420
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds(175.8 mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves(72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.237-241
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• 2014

We investigated the optimal etching conditions and properties of the surface change due to molten KOH/NaOH chemical wet etching using an AlN wafer which has been put to practical use in the present study. Results were observed using a scanning electron microscope after 5 minutes etching at $350^{\circ}C$, was found to have a surface form of the respective other Al-face, the N-face. In particular, etch-pit in the form of a hexagon, which is observed in the Al-face appeared, It was calculated at $2{\times}10^6/cm^2{\sim}10^{10}/cm^2$ dislocation density. In the case of N-face, lattice defects in the form of the hexagonal pyramids is formed. It was discovered that in order to observe the orientation of the wafer, which corresponds to the C-axis direction of the resulting hexagonal AlN which was analyzed using XRD (0002) and is a state of being oriented in the (0004) plane. The Radius of curvature of AlN wafer was 1.6~17 m measured by DC-XRD rocking curve position.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.172-177
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• 2007

The hydrolysis reaction of sarin(GB), one of the nerve agents was studied in aqueous sodium hydroxide(NaOH) solutions to find the experimental conditions which can convert GB into the less toxic compounds. 10 wt% of GB was added into the aqueous NaOH(2.05 eq) in a small-scale jacket-attached reactor connected to a circulator. The reaction rate constants were measured at three temperatures(50, 70 and $90^{\circ}C$) and the reaction times required to degrade the material to > 99% were calculated at different temperatures. In this study, 10 wt% of GB was degraded to 99.99% in 1.2hr at $90^{\circ}C$ by the aqueous NaOH solution. The major hydrolysate of GB was isopropyl methylphosphonate.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2016-2023
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• 2015

Xylanase plays important roles in a broad range of industrial production as a biocatalyst, and its applications commonly require immobilization on supports to enhance its stability. Aluminum hydroxide, a carrier material with high surface area, has the advantages of simple and low-cost preparation and resistance to biodegradation, and can be potentially used as a proper support for xylanase immobilization. In this work, xylanase from Thermomyces lanuginosus was immobilized on two types of aluminum hydroxide particles (gibbsite and amorphous Al(OH)₃) through adsorption, and the properties of the adsorbed enzymes were studied. Both particles had considerable adsorptive capacity and affinity for xylanase. Xylanase retained 75% and 64% of the original catalytic activities after adsorption to gibbsite and amorphous Al(OH)₃. Both the adsorptions improved pH and thermal stability, lowered activation energy, and extended lifespan of the immobilized enzyme, as compared with the free enzyme. Xylanase adsorbed on gibbsite and amorphous Al(OH)₃ retained 71% and 64% of its initial activity, respectively, after being recycled five times. These results indicated that aluminum hydroxides served as good supports for xylanase immobilization. Therefore, the adsorption of xylanase on aluminum hydroxide particles has promising potential for practical production.

• Corrosion Science and Technology
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• v.10 no.4
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• pp.125-130
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• 2011

This study was performed to improve the corrosion resistance and the stability of passive film on copper tube by potentiostatic polarization method in synthetic tap water. Formation of passive film was carried out by anodic potentiostatic polarization at various passivation potentials and passivation times in 0.1 M NaOH solution. Stability of passive film and corrosion resistance was evaluated by self-activation time, ${\tau}_0$ from passive state to active state on open-circuit state in 0.1 M NaOH solution. Addition of polyphosphate in NaOH solution prolonged the self-activation time and improved the corrosion resistance, and the addition of 5 ppm polyphosphate was most effective. It was also observed that better corrosion resistance was obtained by potentiostatic polarization at 1.0 V (vs. SCE) than at any other passivation potentials. Passivated copper tube showed perfect corrosion resistance for the immersion test in synthetic tap water showing that the anodic potentiostatic polarization treatment in 0.1 M NaOH with 5 ppm polyphosphate solution would be effective in improving the corrosion resistance and preventing the blue water problem.

• Journal of the Korean Chemical Society
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• v.23 no.6
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• pp.385-391
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• 1979

It was found that cupric ion selective electrode, which was prepared by mixing CuS and $Ag_2S$ with the ratio four to one and PVC, was hard and durable. The response potentials were reproducible and linear in the range from 1.0 ${\times}$ $10^{-1}M$ to 1.0 ${\times}$ $10^{-5}M$ copper (II) solution and its slope was 25.0 mV per decade concentration at $298^{\circ}K$, slightly different from Nernstian slope. The copper (II) indicating electrode was applied in precipitation titration of 1.0 ${\times}$ $10^{-2} M Cu(II)$ sample solution containing proper amounts $NaNO_3$ with 0.1 M NaOH standard solution. Also, this electrode could be used in complex titration of Zn(II), Mg(II), Ca(II) with EDTA and stability constant of EDTA complex of Ca(II) and Mg(II) was calculated by using known Cu-$EDTA^{2-}$ stability constant.