• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.113-117
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• 2001

Specific capacitance and charge-discharge rate of EDLC using activated carbon electrode were affected by the compositions of electrolytes, the conditions of charge-discharge and physical properties of activated carbon materials. The activated carbon electrode was prepared by dip coating method. Charge-discharge test and electrochemical experiments were carried out for various kinds of organic electrolytes. Effects of charge and discharge current density on the specific capacitance were studied. Characteristics of leakage current, self-discharge and time-voltage curves in optimum conditions of organic electrolytes were compared with conventional $1M-Et_4NBF_4/PC$ electrolyte. The EDLC using MSP-20(specific surface area: $2000m^2/g$) electrode and $1M-LiPF_6/PC-DEC(1:1)$ was exhibited th highest specific capacitance of 130F/g and low polarization resistances. The EDLC using MSP-20 electrode at $1M-LiPF_6/PC-DEC(1:1)$ was small leak current of 0.0004A for 15min, long voltage retention of 0.8V after 100h and linear time-voltage curves with small IR-drop.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.4
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• pp.201-209
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• 2016

Theoretical maximum methane yield of glucose at STP (1 atm, $0^{\circ}C$) is 0.35 L $CH_4/g$ COD. However, most researched actual methane yields of anaerobic digester (AD) on lab scale is lower than theoretical ones. A wide range of them have been reported according to experiments methods and types of organic matters. Recent year, a MET (Microbial electrochemical technology) is a promising technology for producing sustainable bio energies from AD via rapid degradation of high concentration organic wastes, VFAs (Volatile Fatty Acids), toxic materials and non-degradable organic matters with electrochemical reactions. In this study, methane yields of food waste leachate and sewage waste sludge were evaluated by using BMP (Biochemical Methane Potential) and continuous AD tests. As the results, methane production volume from the anaerobic digester equipped with MET (AD + MET) was higher than conventional AD in the ratio of 2 to 3 times. The actual methane yields from all experiments were lower than those of theoretical value of glucose. The methane yield, however, from the AD + MET occurred similar to the theoretical one. Moreover, biogas compositions of AD and AD + MET were similar. Consequently, methane production from anaerobic digester with MET increased from the result of higher organic removal efficiency, while, further researches should be required for investigating methane production mechanisms in the anaerobic digester with MET.

• Korean journal of food and cookery science
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• v.29 no.5
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• pp.453-462
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• 2013

Recently, two formulas of sulgidduk added to pine needle juice (PNJ) with various physiological activities were developed for metabolic syndrome patients in our lab. According to previous studies, cooking may alter antioxidant properties by initiating destruction, release or transformation of antioxidant compounds contained in food. Therefore, the aim of this study was to compare the antioxidant activities and antigenotixic effects of sulgidduk with/without PNJ and to note changes in these activities after cooking. The ingredients of sulgidduk was added on the basis of 100% rice flour as follows: conventional sulgidduk (S): 1.5% salt, 30.0% sugar; PNJ added to sulgidduk A (PS-A): 1.4% salt, 30.0% sugar, and 1.0% PNJ; PNJ added to sulgidduk B (PS-B): 1.5% salt, 21.4% sugar, and 1.4% PNJ. Ethanol and water extracts of sulgidduk were analyzed for the total phenolic content (TPC), DPPH radical scavenging activity (DPPH RSA), total radical-trapping antioxidant potential (TRAP), oxygen radical absorbance capacity (ORAC), and antigenotoxic effect by comet assay. The ethanol extracts PS-A and PS-B showed higher TPC and antioxidant activities (DPPH RSA, TRAP, and ORAC) than did the S ethanol extract before cooking. The more PNJ was added, the higher TPC and anitoxidant activities were observed in sulgidduk (PS-A$200{\mu}M$ of $H_2O_2$. Taken together, this study suggests that sulgidduk added to 1.44% of pine needle juice may be a good option antioxidant and antigenotoxic source.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.37-43
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• 2008

The research attempted to develop an eco-friendly wood adhesive based on vegetable oil (soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The soybean oils (SBO) were reacted with $O_3$ at the rate of 7.13 g/h for different times, 15 minutes, 30 minutes, 60 minutes, and 120 minutes. Modified chemical structure of the ozonized SBOs were examined by Fourier transform Infrared (FT-IR) spectrum. The FT-IR spectrum of SBO had an absorbance peak at $3010cm^{-1}$ that is the characteristic peak of the unsaturated double bonds. As ozone treatment time increased, the peak of the double bond was disappeared and aldehyde or carboxyl peak appeared at $1700cm^{-1}$. The dry, wet, and cyclic boiling bond strengths of the ozonized SBO mixed with polymeric diphenylmethane-4, 4-diisocyanate (pMDI) were also investigated. In the dry shear test, all strengths met constantly the standard requirement of $7.0kgf/cm^2$ (KS F3101 2006). The bond strengths gradually increased with increasing ozone treatment time. The highest strength showed at 60 minutes ozone treatment and decreased values at 120 minutes. In the cyclic boiling shear test, 30, 60 and 120 minutes exceeded the standard requirement.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.246-246
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• 2012

Smart catalyst design though novel catalyst preparation methods can improve catalytic activity of transition metals on reducible oxide supports such as titania by enhancement of metal oxide interface effects. In this work, we investigated Pt nanoparticles/titania catalysts under CO oxidation reaction by using novel preparation methods in order to enhance its catalytic activity by optimizing metal oxide interface. Arc plasma deposition (APD) and metal impregnation techniques are employed to achieve Pt metal deposition on titania supports which are prepared by multi-target sputtering and Sol-gel techniques. In order to tailor metal-support interface for catalytic CO oxidation reaction, Pt nanoparticles and thin films are deposited in varying surface coverages on sputtered titania films using APD. To assess the role of oxide support at the interface, APD-Pt is deposited on sputtered and Sol-gel prepared titania films. Lastly, characteristics of APD-Pt process are compared with Pt impregnation technique. Our results show that activity of Pt nanoparticles is improved when supported over Sol-Gel prepared titania than sputtered titania film. It is suggested that this enhanced activity can be partly ascribed to a very rough titania surface with the higher free metal surface area and higher number of sites at the interface between the metal and the support. Also, APD-Pt shows superior catalytic activity under CO oxidation as compared to Pt impregnation on sputtered titania support. XPS results show that bulk oxide is formed on Pt when deposited through impregnation and has higher proportion of oxidized Pt in the form of $Pt^{2+/4+}$ oxidation states than Pt metal. APD-Pt shows, however, mild oxidation with large proportion of active Pt metal. APD-Pt also shows trend of increasing CO oxidation activity with number of shots. The activity continues to increase with surface coverage beyond 100%, thus suggesting a very rough and porous Pt films with higher active surface metal sites due to an increased surface area available for the reactant CO and $O_2$ molecules. The results suggest a novel approach for systematic investigation into metal oxide interface by rational catalysts design which can be extended to other metal-support systems in the future.

• Economic and Environmental Geology
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• v.53 no.3
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• pp.297-306
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• 2020

The red mud generated from bauxite during the Bayer alumina production process has been regarded as an industrial waste due to the high alkaline property and high content of Na. Despite of its environmental problem, various studies for recovery of the valuable resources from red mud has been also carried out because of high content (25.7 wt.% as Fe₂O₃ in this study) of iron in red mud. In order to recover the iron resource in the red mud, microwave heating experiments were performed with adding of activated carbon and elemental sulfur to the red mud. Through the microwave heating the powdered red mud mixtures converted to porous and vitrified solid aggregates. The vitrified aggregates produced by microwave heating are composed of goethite, zero valent iron (Fe⁰), pyrrhotite and pyrite. And then, the microwave heating samples were dissolved in the aqua regia solution, and Fe precipitates were obtained as a Fe-chlorides by adding of NaCl salt in the aqua regia solution. The Fe recovery rates in the Fe-chloride precipitates showed differences depending on the experimental mixture conditions, and Fe grades of the end products are 49.0 wt.%, 58.0 wt.% and 59.5 wt.% under mixture conditions of red mud, red mud + activated carbon, and red mud + activated carbon + elemental S, respectively. The Fe content of 56.0 wt.% is generally known as the grade value of Fe in a iron ore for iron production, and the Fe grades of microwave heating samples with adding activated carbon and elemental S in this study are higher than the grade value of 56.0 wt.%.

• Food Science and Preservation
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• v.9 no.1
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• pp.102-108
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• 2002

The purpose of this study was to investigate antibacterial activity of extracts of Cordyceps spp.(Paecilomyces japonica and Cordyceps militaris), mugwort and pine needle. Fruiting body and mycelium of Cordyceps spp., mugwort and pine needle were extracted with water and 70% ethanol. Antibacterial activities of each extracts against 3 kinds of Gram positive (Bacillus subtilis, Listeria monocytogenes and Staphylococcus aureus) and 3 kinds of Gram negative pathogenic bacteria(Escherichia coli O157 : H7, Shigella sonnei and Salmonella typhimurium) were tested. The yields of water and ethanol extracts of fruiting body (39∼58%) were 2.4 ∼4.4 times higher than mycellium(9∼24%) in Cordyceps sup., while those of mugwort and pine needle were less than 9%. Ethanol extract of P. japonica mycelium(JFE) had antibacterial to S. monocytogenes at 1% level and ethanol extract of C. militaris fruiting body (MFE) had antibacterial to S. aureus at 3% level. Ethanol extract of mugwort was antibacterial against L monocytogenes and S. aureus at 1% level. Water extracts of Cordyceps spp.(P. japonica and C. militaris) and mugwort had no antibacterial activity against tested bacterial strains. Water extract of pine needle had antibacterial activity against all bacterial strains except E. coli and ethanol extract had antibacterial activity against all tested bacterial strains at 1% level. Pine needle extracts had the most wide antibacterial spectrum against bacterial strains used for this experiment. Growth inhibiting activities of pine needle extracts were higher in ethanol extract than water extract for most of tested bacteria in tryptic soy broth.

• Korean Journal of Materials Research
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• v.30 no.8
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• pp.383-392
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• 2020

In this paper, AgCl/Ag₃PO₄/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag₃PO₄/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag₃PO₄/diatomite composite under visible light are evaluated. In the AgCl/Ag₃PO₄/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag₃PO₄/diatomite remains at 95 % of the original level, much higher than that of pure Ag₃PO₄ (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag₃PO₄/diatomite composites can be attributed to the synergistic effect of Ag₃PO₄, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO₂ and H₂O. Even more remarkably, AgCl/Ag₃PO₄/diatomite can maintain above 95 % photo-degradation activity after five cycles.

• Korean journal of food and cookery science
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• v.33 no.2
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• pp.127-136
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• 2017

Purpose: This study examined the effect of different gluten-free flours on the properties of cookies. Methods: Each gluten-free cookie was made from wheat, brown rice, buckwheat, corn, sorghum, teff, or black rice. Results: Baking loss was highest on sorghum (18.85%) and the lowest on teff (12.73%). The spread factor was highest on brown rice (8.20) and lowest on corn (7.60). The density was similar in all samples (1 g/mL). pH was the highest on buckwheat (6.45) and lowest on wheat (5.96). While L-value, a-value and b-value were lowest on black rice, the ${\Delta}E-value$ was the highest on black rice (35.57). The hardness was highest on wheat (30.28 N) and lowest on teff (14.87 N). The polyphenol and flavonoid content was the highest on buckwheat ($25.97{\mu}g\;GAE/mg$) and the flavonoid content was the highest on black rice ($24.33{\mu}g\;QE/mg$). The DPPH IC50 value was highest on wheat ($352.41{\mu}g/mL$) and lowest on black rice ($33.59{\mu}g/mL$). The ABTS $IC_{50}$ value was highest on wheat ($349.30{\mu}g/mL$) and lowest on black rice ($57.72{\mu}g/mL$). The results of the sensory properties revealed color to be highest on corn (7.33). The top grain was similar in all the samples (5.43-6.57). Flavor was highest on black rice and teff (6.43-6.48). The softness was the highest on wheat, sorghum, teff, and black rice (6.48-7.05). Sweetness was highest on sorghum, teff, and black rice (6.19-6.71). The overall preference also was highest on sorghum, teff, and black rice (6.14-6.48). Conclusion: Gluten-free flours can improve the quality characteristics and antioxidant activities of cookies.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.375-379
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• 1995

Contents of ${\beta}-carotene$ and vitamin C in the vegetable(Angelica keiskei) juice were measured as a function of storing temperature$(-18^{\circ}C{\sim}35^{\circ}C)$ and period$(6{\sim}72\;hours)$. Content of ${\beta}-carotene$ was highest in the fresh juice and the degree of destruction of the ${\beta}-carotene$ was significantly increased as the storage temperature increased. Vitamin C in the juice stored at $4^{\circ}C$ decreased less than that of ${\beta}-carotene$. There was no significant difference in fatty acid compositions among in the fresh, freeze-dried juice and juice stored for 72 hours. Antioxidative activities of components extracted from the juice(fresh and stored for 24 hours) followed by incubating for 1 day were higher than that of ${\alpha}-tocopherol$ and then significantly decreased as incubation prolonged.