• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.975-984
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• 2018

The purpose of that was to investigate the potential of P. Herba extracts as phytonutrient active ingredients. In order to elucidate the P.Herba ethanol extracts were examined DPPH radical scavenging activity, NO production, protective effects against oxidative stress in HaCaT cells, anti-inflammatory activity, antimicrobial activity, anti-allergic effects, and inhibition of ${\beta}$-hexosaminidase expression. The antioxidative activity of the P. Herba extracts was compared, and the antioxidative activity of the ethanol extract was found to be superior. No significant cytotoxicity was observed in HaCaT, RAW 264.7, and RBL-2H3 cells. The protective effect of the extracts against oxidative stress induced by hydrogen peroxide ($H_2O_2$) was examined in HaCaT cells, and it was found to be 83% This concentration refers to which extract ethanol at $100{\mu}g/mL$. The anti-inflammatory activity of the extracts was examined in RAW 264.7 cells, and NO production was suppressed even at low concentrations. In addition, the concentration-dependent antimicrobial activities of the extracts were demonstrated in several bacterial strains, such as those of S.aureus, S.epidermidis and P. acnes. Based on the findings from this study, Portulacae Herba extracts could be used as physiological active substance that possess antioxidative, anti-inflammatory, and antimicrobial properties.

• Journal of Animal Science and Technology
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• v.52 no.3
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• pp.199-204
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• 2010

The objective of this study was to evaluate the effect of the different types and levels of prebiotics on intestinal microflora and fermentation products in the in vitro fermentation model. The prebiotcs used in this study were IMO (iso-malto oligosaccharide), CI (partially digested chicory-inulin), RA (raffinose) and CD (cyclodextrin). Experimental diet for growing pigs was predigested by digestive enzymes and this hydrolyzed diet was mixed with buffer solution containing 5% fresh swine feces. Then, the mixture was fermented with or without prebiotics at the concentrations of 0.5 and 1.0% for 24 h. Samples were taken at 24 h, and viable count of micoflora, gas, pH, volatile organic compounds and short-chain fatty acids were determined. The viable count of Enterobacteriaceae was significantly decreased (p<0.001) in all treatments added with prebiotics in comparison to control without prebiotics. However, the increase of lactic acid bacteria was observed in the prebiotics treatment. Gas production increased as the level of prebiotics increased. The pH values in the fermentation fluid decreased in a dose-dependent manner with increasing the concentration of prebiotics. The fermentation with prebiotics resulted in the reduction of malodorous compounds such as ammonia, hydrogen sulfide, indole and skatole. The increase in short-chain fatty acid (SCFA) production was observed in the treatments with prebiotics. In conclusion, the results of this study demonstrated that the fermentation with prebiotics was effective in reducing the formation of malodorous compounds and increasing lactic acid bacteria and SCFA. These effects depended on the concentration of prebiotics. Moreover, further study is needed to determine whether the in vitro efficacy on the reduction of malodorous compounds and increase of SCFA would also be observed in animals.

• Journal of Space Technology and Applications
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• v.3 no.3
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• pp.199-212
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• 2023

In contrast to the short-term nature of lunar missions in the past, lunar missions in new space era aim to extend the presence on the lunar surface and to use this capability for the Mars exploration. In order to realize extended human presence on the Moon, production and use of consumables and fuels required for the habitation and transportation using in-situ resources is an important prerequisite. The Global Exploration Roadmap presented by the International Space Exploration Coordination Group (ISECG), which reflects the space exploration plans of participating countries, shows the phases of progress from lunar surface exploration to Mars exploration and relates in-situ resource utilization (ISRU) capabilities to each phase. Based on the ISRU Gap Assessment Report from the ISECG, ISRU technology is categorized into in-situ propellant and consumable production, in-situ construction, in-space manufacturing, and related areas such as storage and utilization of products, power systems required for resource utilization. Among the lunar resources, leading countries have prioritized the utilization of ice water existing in the permanent shadow region near the lunar poles and the extraction of oxygen from the regolith, and are preparing to investigate the distribution of resources and ice water near the lunar south pole through unmanned landing missions. Resource utilization technologies such as producing hydrogen and oxygen from water by hydroelectrolysis and extracting oxygen from the lunar regolith are being developed and tested in relevant lunar surface analogue environments. It is also observed that each government emphasizes the use and development of the private sector capabilities for sustainable lunar surface exploration by purchasing lunar landing services and providing opportunities to participate in resource exploration and material extraction.

• Journal of Life Science
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• v.23 no.3
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• pp.443-447
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• 2013

This study was conducted to investigate the antimicrobial and anti-oral malodor effect of Schizandra chinensis extracts against oral pathogens. S. chinensis methanol (MeOH) extract showed better antimicrobial activities against oral pathogens than the S. chinensis hot water extract did. In particular, ethylacetate (EA) fraction of S. chinensis MeOH extract had the greatest effects against Streptococcus mutans, S. sanguinis, S. salivaris subsp. thermophols and Porphyromons gingivalis. The anti-malodor effect of S. chinensis against the generation of volatile sulfur compounds (VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, was estimated using oral chroma in a practical study. The results showed that 2% MeOH extract of S. chinensis against the production of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide had inhibitions of 91.15, 78.72 and 71.58%, respectively. These results showed that Schizandra chinensis extract had antimicrobial activity against several oral pathogens and exhibited significant effects on the inhibition of VSCs. Thus, Schizandra chinensis extract could be an alternative to available synthetic chemicals and oral hygiene products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.126-132
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• 2016

This study numerically investigates the characteristics of chemical reactions and thermal deformation in a steam reformer. These phenomena are significantly affected by the high-temperature burner gas and the process gas conditions. Because the high temperature of the burner gas ranges from 800 to 1000 K, the reformer tubes undergo substantial thermal deformation, eventually resulting in structural failure. Thus, it is necessary to understand the characteristics of the reaction and thermal deformation under the operating conditions to evaluate the reformer tubes for sustainable, stable operation. Extensive numerical simulations were carried out using commercial CFD code (ANSYS FLUENT/MECHANICA Ver. 13.0) while considering three-dimensional turbulent flows and combined heat transfer including conduction, convection, and radiation. Structural analysis considering conjugated heat transfer between solid tubes and fluid flows was conducted using the Fluid-Solid Interaction (FSI) method. The results show that when the injection temperature of the process gas and burner gas decreased, the hydrogen production rate decreased significantly, and thermal deformation decreased by at least 15 to 20%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.1
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• pp.30-35
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• 2024

In order to improve the efficiency of the water splitting system for hydrogen production, the high overvoltage in the electrochemical reaction caused by the catalyst in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be reduced. Among them, transition metal-based compounds are attracting attention as catalyst materials that can replace precious metals such as platinum that are currently used. In this study, nickel foam, an inexpensive metal porous material, was used as a support, and Fe-doped β-Ni(OH)₂ microcrystals were synthesized through a hydrothermal synthesis process. In addition, in order to improve OER properties, changes in the shape, crystal structure, and water splitting characteristics of Fe-Mo co-doped β-Ni(OH)₂ microcrystals synthesized by co-doping with Mo were observed. The changes in the shape, crystal structure, and applicability as a catalyst for water splitting were examined.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.1061-1066
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• 2003

The present study was performed to investigate the effect of ozonation of the swine nursery building on indoor air quality and growth efficiency of the weanling piglets. Forty 21-day-old, cross-bred weanling piglets were housed in two ozonated or unozonated pens(10 males and 10 females per pen) for 3 wk alternately in a swine nursery building and this procedure was repeated three times. Ozone was generated using a commercial apparatus outside the nursery building and infused into the nursery building through a duct at a level of 0.03 ppm. Indoor concentrations of harmful gases were measured at 2-h intervals for a 24-h period per each 3-wk feeding trial. Indoor ammonia and carbon dioxide gas concentrations were reduced by the ozonation(P〈0.01) by 21% and 7%, respectively, compared with those of the control(unozonation), although hydrogen sulfide concentration was not affected by the treatment. However, the weight gain, feed intake and feed/gain of the piglets did not change due to the ozonation. Results suggest that ozonation of the swine nursery building is effective for improving the indoor air quality without affecting the production efficiency of weanling piglets.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.381-389
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• 2015

In this study, the effects of moisture content and particles size of ground particles of torrefied larch chips on the pelletizing process were investigated depending on torrefaction conditions ($220^{\circ}C$-50 min, $250^{\circ}C$-50 min, $250^{\circ}C$-120 min). The moisture content in the torrefied chip decreased to 0.69~1.75%, while ash content and calorific value increased compared to untreated chip. In addition, weight loss significantly increased during torrefaction due to hemicellulose degradation. The carbon content in torrefied larch chip increased compare to untreated larch chip, while the hydrogen and oxygen contents decreased. The lignin and glucan contents in torrefied larch chip increased with increasing severity of the torrefaction condition, while hemicellulose decreased. In the particle size distribution of ground particles of torrefied larch chip, larch torrefied at severe conditions was found to produce smaller particles (~1 mm) than that of the larch torrefied at mild conditions. Macropore (over $500{\AA}$) in the torrefied particle was produced during torrefaction. During the pelletizing using ground particles of torrefied larch chip, the pressure needed in pelletizing decreased and pellet length increased with increasing moisture content, regardless of the particle size.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.59-71
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• 2021

Hybrid hydrothermal carbonization (Hybrid HTC) technology is a proprietary thermochemical process for two or more organic wastes.The reaction time is less than two hours with temperature range 180~250℃ and pressure range 20~40bar. Thanks to accumulation of the carbon of the waste during Hybrid HTC process, the energy value of the solid fuel increases significantly with comparatively low energy consumption. It has also a great volume reduction with odor removal effect so that it is evaluated as the best solid fuel conversion technology for various organic wastes. In this study of the hybrid hydrothermal carbonization, the effect on the calorific value and yield of Cambodian mango waste were evaluated according to changes in temperature and reaction time. Through the study, parameter optimization has been sought with improving energy efficiency of the whole plant. It is decomposed in the Hydro-Carbonation Technology to Generate Gas. At this time, it is possible to develop manufacturing and production technologies such as hydrogen (H₂) and methane (CH₄). Based on the results of the study, a pilot plant (2t/day) has been proposed for future commercialization purpose along cost analysis, mass balance and energy balance calculations.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.1-10
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• 2014

In papermaking industry, inorganic fillers are widely used for the purpose of improving opacity, brightness, printability, uniformity and dimensional stability. They are also useful for production costs and energy savings. In the past, inorganic fillers in papermaking industry only focused on micro-scale but recently, new trials on nano-powdered technology are applying. Even nano-powdered fillers are rapidly utilized for improving the optical and surface properties in coating and surface sizing, there still have some problems in wet-end process due to poor dispersibility and retention. In this study, nano-particled calcium carbonate was produced by milling the PCC and its applicability between micro sized and nano sized calcium carbonated was compared in wet-end process, and finally the sheet properties were evaluated. Nano-PCC was not retained in sheet structure without applying retention system, but with retention system nano-powdered PCC was absorbed on fiber surface with expanding the fiber networks. The application of PAM-bentonite system has resulted in high ash retention and bulky structure for copier paper, and good optical properties in brightness and opacity. However, it required to solve the weakness of low tensile property due to interruption of hydrogen bonding by nano fillers.