• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.498-506
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• 2016

A croquette added with heat-treated kimchi at 20% showing higher sensory preferences was analyzed for its physicochemical properties and antioxidant activity using a croquette without kimchi as a control. Compared with the control, kimchi-added croquette had 3.3-fold higher organic acids content (p<0.001), resulting in a significant reduction of pH (p<0.001) and higher metal chelating activity (p<0.001). Upon addition of kimchi, total reducing capacity increased from 109.4 to $139.4{\mu}g/g$ gallic acid equivalents (p<0.01), and DPPH radical scavenging activity also increased 2-fold, which corresponded to 54% of the electron-donating ability of 0.35 mM gallic acid. In addition, contents of free amino acids and ${\gamma}-aminobutyric$ acid (GABA) appreciably increased by 1.6-fold (p<0.01) and 10-fold (p<0.001), respectively. This could be attributed to the ingredients of kimchi and/or enzymatic transformation of precursors by microorganisms during kimchi fermentation. Kimchi-added croquette was determined to be a good source of dietary fiber relative to its calorie content. Texture profile analysis showed no significant differences in hardness, springiness, cohesiveness, gumminess, and chewiness between the two croquettes with or without kimchi. Taken together, this study shows that utilization of heat-treated kimchi as a filling for croquette could be a good strategy to improve both the nutritional quality and antioxidant activity of croquette.

• Journal of IKEEE
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• v.26 no.4
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• pp.537-544
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• 2022

This paper analyzes the occurrence and cause of bond wires fusing used in the manufacture of pulsed high power amplifiers. Recently GaN HEMT has been spotlight in the fields of electronic warfare, radar, base station and satellite communication. In order to produce the maximum output power, which is the main performance of the high-power amplifier, optimal impedance matching is required. And the material, diameter and number of bond wires must be determined in consideration of not only the rated current but also the heat generated by the transient current. In particular, it was confirmed that compound semiconductor with a wide energy band gap such as GaN trigger fusing of the bond wire due to an increase in thermal resistance when the design efficiency is low or the heat dissipation is insufficient. This data has been simulated for exothermic conditions, and it is expected to be used as a reference for applications using GaN devices as verified through IR microscope.

• Clean Technology
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• v.27 no.4
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• pp.359-366
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• 2021

Halloysite nanotubes (HNTs), the multiwalled clay mineral with the composition of Al₂Si₂O₅(OH)₄·nH₂O, have been highlighted as a low-cost adsorbent for the removal of dyes from wastewater. Although a powder of halloysite presents a high specific surface area, forming media are significantly considered due to sludge-clogging induced by the water-bound agglomeration. However, higher firing temperature to achieve the structural durability of the media and lower utilization rate due to longer penetration depth into the media act as hurdles to increase the dye-adsorption capacity. In this work, the retention of the adsorption capacity of halloysite was evaluated with methylene blue solution after the heat treatment at 750 ℃. In order to improve the utilization rate, tubular media were fabricated by extrusion. The images taken by transmission electron microscopy show that HNTs present excellent structural stability under heat treatment. The HNTs also provide superb capacity retention for MB adsorption (93%, 18.5 mg g^-1), while the diatomite and Magnesol^® XL show 22% (7.65 mg g^-1) and 6% (11.7 mg g^-1), respectively. Additionally, compositing with lignin enhances adsorption capacity, and the heat treatment under the hydrogen atmosphere accelerates the adsorption in the early stage. Compared to the rod-type, the tubular halloysite media rapidly increases methylene blue adsorption capacity.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.639-645
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• 2020

Among the components of redox flow battery (RFB), the electrode serves as a diffusion layer of an electrolyte and a path for electrons and also is a major component that directly affects the RFB performance. In this paper, chloric/sulfuric mixed acidwas used as a supporting electrolyte in RFB system with Fe2+/Fe3+ and V2+/V3+ as redox couple. The optimum electrode and activation temperature were suggested by comparing the capacity, coulombic efficiency and energy efficiency according to the electrode type and activation temperature. In the RFB single cell evaluation using 5 types of carbon electrodes used in the experiments, all of them showed close to the theoretical capacity to retain the reliability of the evaluation results. GFD4EA showed relatively excellent energy efficiency and charge/discharge capacity. In order to investigate the electrochemical performance according to the activation temperature, GFD4EA electrode was activated by heat treatment at different temperatures of 400, 450, 500, 600 and 700 ℃ under an air atmosphere. Changes in physical properties before and after the activation were observed using electrode mass retention, scanning electron microscope (SEM), XPS analysis, and electrochemical performance was compared by conducting RFB single evaluation using electrodes activated at each temperature given above.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1598-1608
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• 2013

An optimum dietary carbohydrate content is important for maximum fish growth. In this study, we fed Wuchang bream (Megalobrama amblycephala) with either control diet (30.42%) or high carbohydrate diet (52.92%) for 90 d. Fish were fed to apparent satiation three times daily in an aquarium with automatic temperature control and circulated water. Growth performance, plasma biochemical parameters, hepatic morphology and enzyme activities were determined. It was shown that compared to fish fed control diet, fish fed high carbohydrate diet had higher plasma triglyceride and cortisol levels for d 90, and lower alkaline phosphatase level for d 45, lower hepatic superoxide dismutase and total antioxidative capacity for d 90, higher malondialdehyde for d 45 and glycogen content for d 45 and 90 (p<0.05). Histological and transmission electron microscopy studies showed that hepatocytes of fish fed high carbohydrate diet contained large lipid droplets, causing displacement of cellular organelles to periphery of hepatocytes. The relative level of hepatic heat shock protein 70 (HSP70) mRNA of Wuchang bream fed high carbohydrate diet was significantly higher than that of fish fed the control diet for 90 d (p<0.05). These changes led to decreased specific growth rate and increased feed conversion ratio (p<0.05). Upon hypoxia challenge, fish fed high carbohydrate diet had higher cumulative mortality than those fed the control diet (p<0.05). These results suggested that high dietary carbohydrate (52.92%) was detrimental to the growth performance and health of Wuchang bream.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.2
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• pp.25-29
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• 2001

This study examined the effects of carbon surface modification by the epoxy resin coating on the electrochemical performance. The mesocarbon microbeads(MCMB) carbon was surface-modified by coating the epoxy resin and its electrochemical properties as an anode was examined. The surface coating of MCMB was carried out by refluxing the MCMB powders in a dilute H2SO4 solution, and mixing them with the epoxy resin-dissolved tetrahydrofuran(THF) solution. Under heat-treatment of the coated MCMB at the temperature over $1000^{\circ}C$, the epoxy-resin coating layer was converted into amorphous phase which was identified by a high resolution transmission electron microscope (HRTEM). The epoxy resin coated MCMB has higher Brunauer-Emmett-Teller (BET) surface area, higher charge/ discharge capacity and better cycleability than a raw MCMB without coating. The reason for the enhancement of cell performance by the epoxy resin coating were considered as the epoxy resin coating layer plays an important role to be a barrier for carbon reacting with electrolyte and to retard the formation of passivation layer.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.327-333
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• 2008

To develop a functional juice using garlic (Allium sativum L.), heated garlic juice was investigated using a central composite design set with variables of treatment temperature (110, 115, 120, 125, and $130^{\circ}C$) and time (1, 2, 3, 4, and 5 hr) using high temperature and pressure treatment apparatuses. Total soluble solid, total acidity, reducing sugar, total pholyphenol contents, electron donating activity (EDA), and ascorbic acid equivalent antioxidant capacity (AEAC) in heated garlic juice were increased with increasing heating temperature and time. The highest total soluble solid content was $17.81\;^{\circ}brix$ at $123.10^{\circ}C$ for 1.10 hr. The highest total acidity was 1.43% at $127.35^{\circ}C$ for 4.35 hr. The highest reducing sugar content was 86.67 mg/mL at $119.90^{\circ}C$ for 4.35 hr. The highest total polyphenol content was 8.42 mg/mL at $127.75^{\circ}C$ for 4.26 hr. The highest EDA and AEAC were 60.09%, and 7.40 mg AA eq/mL at $127.85^{\circ}C$ for 4.23 hr, and $128.10^{\circ}C$ for 4.18 hr, respectively.

• Journal of the Korean Electrochemical Society
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• v.6 no.4
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• pp.229-235
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• 2003

A precursor of lithium manganese oxide was synthesized by mixing $(CH_3)_2CHOLi\;with\;Mn(CH_3COO)_2{\cdot}4H_2O$ in ethanol using a sol-gel method, then heat-treated at $400^{\circ}C\;and\;800^{\circ}C$ in air atmosphere. The condition of heat treatment was determined by thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTA). The characterization of the lithium manganese oxide was done by X-ray diffraction (XRD) spectra and scanning electron microscopy (SEM). The electrochemical characteristics of lithium manganese oxide electrode for lithium ion battery were measured by cyclic voltammetry (CV), chronoamperometry and AC impedance method using constant charge/discharge process. The electrochemical behaviors of the electrode have been investigated in a 1.0M $LiClO_4/propylene$ carbonate electrolyte solution. The diffusivity of lithium ions, $D^+\;_{Li}\;^+$, as determined by AC impedance technique was $6.2\times10^{-10}cm^2s^{-1}$.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.140-147
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• 2016

A process for manufacturing virally-safe porcine bone hydroxyapatite (HA) has been developed to serve as advanced xenograft material for dental applications. Porcine bone pieces were defatted with successive treatments of 30% hydrogen peroxide and 80% ethyl alcohol. The defatted porcine bone pieces were heat-treated in an oxygen atmosphere box furnace at $1,300^{\circ}C$ to remove collagen and organic compounds. The bone pieces were ground with a grinder and then the bone powder was sterilized by gamma irradiation. Morphological characteristics such as SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) images of the resulting porcine bone HA (THE Graft$^{(R)}$) were similar to those of a commercial bovine bone HA (Bio-Oss$^{(R)}$). In order to evaluate the efficacy of $1,300^{\circ}C$ heat treatment and gamma irradiation at a dose of 25 kGy for the inactivation of porcine viruses during the manufacture of porcine bone HA, a variety of experimental porcine viruses including transmissible gastroenteritis virus (TGEV), pseudorabies virus (PRV), porcine rotavirus (PRoV), and porcine parvovirus (PPV) were chosen. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the $1,300^{\circ}C$ heat treatment. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.81$$ for PRV, $${\geq_-}6.28$$ for PRoV, and $${\geq_-}5.21$$ for PPV. Gamma irradiation was also very effective at inactivating the viruses. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the gamma irradiation. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.87$$ for PRV, $${\geq_-}6.05$$ for PRoV, and $${\geq_-}4.89$$ for PPV. The cumulative log reduction factors achieved using the two different virus inactivation processes were $${\geq_-}9.30$$ for TGEV, $${\geq_-}11.68$$ for PRV, $${\geq_-}12.33$$ for PRoV, and $${\geq_-}10.10$$ for PPV. These results indicate that the manufacturing process for porcine bone HA from porcine-bone material has sufficient virus-reducing capacity to achieve a high margin of virus safety.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.502-508
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• 1997

Rice bran dietary fiber extract, which was obtained after termamyl treatment of defatted rice bran contained $27.3{\sim}30.5%$ protein, $49.7{\sim}54.1%$ insoluble dietary fiber, and $1.9{\sim}2.7%$ soluble dietary fiber. Extrusion decreased the insoluble dietary fiber content but increased the soluble dietary fiber content, while roasting did not. Influence those content. Each mineral element content was depended upon heat processing method. Extrusion increased the water binding capacity and L value, while roasting reduced the water binding capacity and L value. Scanning electron microscopy showed damaged cell walls for extruded sample compared to roasted one which had fully collapsed cell walls. The increase of water absorption, developing time, and stability and the of MTI of wheat flour-dietary fiber extract composites with addition of dietary fiber extract were observed by Farinograph. Rice bran dietary fiber extract had an effect on the bread making resulting in increase of bread weight and color of crumb and crust, and decrease of bread volume and texture. As a result of sensory evaluation, appearance, texture, overall acceptability were significantly different from control but flavor and taste were not different significantly up to 6% level. Heat treated samples had differences in mean values, but not significant differences statistically.