• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.191-200
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• 2009

A localized torrential rainfall and flash floods which are more frequently occurred by extraordinary atmospheric phenomena and rising sea surface temperature require more hydrological data collecting and analysis for small watershed. Urban watershed hydrological data monitoring system is needed because of big flood potential damage and lack of urban watershed hydrological data. Therefore, Urban Flood Disaster Management Research Center operates small experimental catchments(Sinnae1, Gunja, and Children's Park) observing and analyzing hydrological data(rainfall, stage, and discharge). In this study, the discharge of combined sewage for Gunja experimental drainage is analyzed with weekly data and day of the week data. Through several analyses in analyzing the urban runoff characteristics and managing the urban sewage system, direct runoff is calibrated and verified by the estimated values of rainfall-runoff model(SWMM).

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.403-409
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• 1998

In this study, the effects of multi-dipole type of magnets on the characteristics of the inductively coupled plasmas and $SiO_2$ etch properties were investigated. As the magnets, 4 pairs of permanent magnets were used and, to etch $SiO_2, C_2F_6, CHF_3, C_4F_8, H_2$, and their combinations were used. The characteristics of the magnetized inductively coupled plasmas were investigated using a Langmuir probe and an optical emission spectrometer, and $SiO_2$ etch rates and the etch selectivity over photoresist were measured using a stylus profilometer. The use of multi-dipole magnets increased the uniformity of the ion density over the substrate location even though no significant increase of ion density was observed with the magnets. The use of the magnets also increased the electron temperature and radical densities while reducing the plasma potential. When $SiO_2$ was etched using the fluorocarbon gases, the significant increase of $SiO_2$ etch rates and also the increase of etch uniformity over the substrate were obtained using the magnets. In case of gas combinations with hydrogen, $C_4F_8/H_2$ showed the highest etch rates and etch selectivities over photoresist among the gas combinations with hydrogen used in the experiment. By optimizing process parameters at 1000 Watts of inductive power with the magnets, the highest $SiO_2$ etch rate of 8000 $\AA$/min could be obtained for 50% $C_4F_8/50% H_2$.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.326-332
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• 2008

Various bacteria were isolated from Korean soil samples based on their capability inhibiting the growth of MRSA strains. Among them, strain YK5 with the highest activity was a Gram positive sporulative bacillus with motility. It did not produce indole and no acid was formed from mannitol by the bacterium. The 16S rRNA sequence of the strain showed $95{\sim}98%$ homology with those of Paenibacillus spp.. The bacterial isolate shared the highest homology with that of P. elgii (98%), but was named as Paenibacillus incheonensis YK5 due to differences in physiological properties. Butanol extract of the P. incheonensis YK5 culture grown in SST medium at $37^{\circ}C$ for 96 hr showed a broad antimicrobial activity against Gram-positive (MRSA and Streptococcus pneumoniae) and negative (Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Escherichia coli, Klebsiella pneumoniae) pathogenic bacteria and fungi (Cryptococcus neoformans and Trichophyton). The antimicrobial activity in the crude extract was stable in a broad range of temperature and pH, $20{\sim}100^{\circ}C$ and $3.0{\sim}6.0$, respectively. Therefore, the antimicrobial activity of P. incheonesis YK5 had potential as a novel antibiotics for pathogens including MRSA.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1109-1116
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• 2002

This study analyzed concentrations of volatile organic compounds (VOCs) produced from incineration of papers at $600^{\circ}C$. The papers used in this study included A4 papers (new, printed with ink-jet, printed with carbon), newspapers (printed with bean oil, printed with a general newspaper ink), packaging box, document envelope, single-use paper cup, and cosmetic tissue. Papers were heated from room temperature upto $600^{\circ}C$ providing air inside of the electric furnace and then they were oxidized for 80 minutes at $600^{\circ}C$ maintaining the same air supply. VOCs emitted from the incineration process were sampled using an air sampling pump and bags for 160 minutes and then the components and concentrations of the VOCs were analyzed by a CC-MS. The most prominent chemical structure of the Vous identified from incineration of the papers was furans and then furans were followed by aromatics and aliphatic alkenes. About 40% of the identified VOCs contained double bonds, which have relatively a high ozone (ground level) formation potential, within their molecular structure. Also, some cancer suspecting compounds like benzene, dichlorormethane and chloroform were identified.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.637-650
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• 2002

This study presents an investigation of the changes of the currents in Kwangyang Bay due to the construction of harbor, reclamation and coastal developments. Currents were simulated by the numerical experiments with a diagnostic multi-level model and using the seasonal oceanographic data of temperature, salinity and ocean current. The values of kinetic and potential energies for the currents were calculated in cases of three topographical changes; before coastal developments, the existing state and after completion of the development project in Kwangyang Bay. The changes of currents due to the coastal developments are as follow; Kinetic energies of tide induced residual currents and wind driven currents decreased by 35~40 percent and 5 percent respectively, however those of density currents increased by 10 percent since the decrease of the coastal areas. Kinetic energy of residual currents including tide induced residual currents, density currents and wind driven currents reduced by 10 percent compared with before the coastal developments. Decrease of current velocity was greatest in summer. Therefore, in summer it was assumed that the Kwangyang Bay is more easily polluted by stratification and decrease of residual current than before the coastal developments carried out.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.151-159
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• 2007

We studied the optimal ranges of water and soil characteristics for wetland plants, particularly Scirpus tabernaemontani (softstem bulrush) and Typha latifolia (broadleaf cattail), which are dominant species with potential for restoration of Korean wetlands. We observed vegetation in S. tabernaemontani and T. latifolia communities from the mid to late June, 2005, and measured characteristics of water environments such as water depth (WD), temperature (WT), conductivity (WC), and concentration of several ions $(NO_3{^-}-N,\;Ca^{2+},\;Na^+,\;Mg^{2+},\;and\;K^+)$, and characteristics of soil environments such as soil texture, organic matter (loss on ignition, LOI), conductivity, and pH. The S. tabernaemontani community was accompanied by Zizania latifolia (Manchurian wildrice), Persicaria thunbergii (Korean persicary), Actinostemma lobatum (lobed actinostemma), and Beckmannia syzigachne (American slough grass), while the T. latifolia community was accompanied by P. thunbergii, T. angustifolia (narrowleaf cattail), and Glycine soja (wild soybean). We defined the optimal range for distribution (ORD) as the range that each plant was crowded. The optimal range of water characteristics for the S. tabernaemontani community was a $WD\;10{\sim}50cm,\;WT\;24.0{\sim}32.0^{\circ}C,\;WC\;100{\sim}500{\mu}S/cm,\;{NO_3}{^-}-N\;0{\sim}60ppb,\;K^+\;0.00{\sim}1.50ppm,\;Ca^{2+}\;7.50{\sim}17.50ppm,\; Na^+\;2.50{\sim}12.50ppm,\;and\;Mg^{2+}\;3.00{\sim}7.00ppm$. In addition, the optimal range of soil characteristics for the S. tabernaemontani community was a soil texture of loam, silty loam, and loamy sand, $LOI\;8.0{\sim}16.0%,\;pH\;5.25{\sim}6.25$, and conductivity $10{\sim}70{\mu}S/cm$. The optimal range of water characteristics for the T. latifolia community was a $WD\;10{\sim}30cm,\;WT\;22.5{\sim}27.5^{\circ}C,\;WC\;100{\sim}400{\mu}S/cm,\;{NO_3}{^-}-N\;0{\sim}60ppb,\;K^+\;0.00{\sim}1.50ppm,\;Ca^{2+}\;0.00{\sim}17.50ppm,\;Na^+\;0.00{\sim}12.50ppm,\;and\;Mg^{2+}\;0.00{\sim}5.00ppm$, and the optimal range of soil characteristics for the T. fatifolia community was a soil texture of loam, sandy loam, and silty loam, LOI $3.0{\sim}9.0%,\;pH\;5.25{\sim}7.25$, and conductivity $0{\sim}70{\mu}S/cm$.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.49-55
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• 2018

Under the era of energy crisis, hydrogen energy is considered as one of the most potential alternative energies. Liquid hydrogen has much higher energy density per unit volume than gas hydrogen and is counted as the excellent energy storage method. In this study, Navier-Stokes equations based on 2-phase model were solved by using a computational fluid dynamics program and the liquefaction process of gaseous hydrogen passing through a cryogenic cooling tube was analyzed. The copper with high thermal conductivity was assumed as the material for cryogenic cooling tube. For different inlet velocities of 5 m/s, 10 m/s and 20 m/s for hydrogen gas, the distributions of fluid temperature, axial and radial velocities, and volume fractions of gas and liquid hydrogens were compared. These research results are expected to be used as basic data for the future design and fabrication of cryogenic cooling tube to transform the hydrogen gas into liquid hydrogen.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.43-50
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• 2014

The purpose of study was to analyze secreted nectar volume, nectar sugar content and amino acid in addition to estimating honey quantities that can ultimately reap in male and female flowers of Evodia daniellii Hemsl.. The maximum blooming period of male flowers was on 24 to 26 July in 2012. On average, nectar volume secreted by nectary was $2.73{\pm}0.73{\mu}L$ from one male flower and nectar concentration showed 17.4%. The maximum blooming period of female flowers was on 7 to 9 August in 2012. Nectar volume secreted by nectary was $0.63{\pm}0.49{\mu}L$ from one female flower and nectar concentration showed 25.7%, averagely. As results of correlation analysis between the meteorological factors and nectar characteristics, we found that nectar quantities and concentration were influenced by temperature and relative humidity. Sugar content was calculated at $48.0{\pm}5.2{\mu}g$ per a male flower and $37.8{\pm}8.7{\mu}g$ per a female flower, which meant that both values were not significantly different (Mann-Whitney's U-test, p=0.400). The minimum estimates of honey harvest for a male and female inflorescence were 67.8 g and 53.5 g, respectively. Analysis of amino acid showed that Serine, Glycine and Alanine were more abundant in male flowers, however Asparatate, Glutamate, Asparagine and Glutamine were more abundant in female flowers.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.410-417
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• 2014

Berries and green tea are underutilized in the food industry despite their great potential as a functional food ingredients. The purpose of this study was to determine the extraction conditions under which total phenolic contents and antioxidant activities of berry and green tea extracts are maximized. Extracts produced using 0-80% ethanol and temperatures ranging from $5-65^{\circ}C$ were evaluated for total phenolic content (TP), as well as for DPPH and ABTS radical-scavenging activities by using response surface methodology. Both ethanol and temperature had significant effects (p<0.05). Ogaja extract produced at $67^{\circ}C$ by using 33% ethanol yielded maximum TP, ABTS, and DPPH values of 23.74 mg GAE/g, 19.77, and 25.04 mg VCE/g, respectively. Optimum conditions for mulberry and raspberry extraction were found to be $65^{\circ}C$ by using 69% and 40% ethanol, respectively. Mulberry and raspberry extracts had TP, DPPH, and ABTS values of 20.74 mg GAE/g, 23.55, and 35.44 mg VCE/g, and 26.08 mg GAE/g, 39.93, and 55.60 mg VCE/g, respectively. Green tea extraction at $57^{\circ}C$ by using 43% ethanol was found to be optimal, yielding TP, ABTS, and DPPH values of 101.15 mg GAE/g, 171.38, and 177.56 mg VCE/g, respectively.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.989-998
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• 2016

Acidic endo-polygalacturonases are the major part of pectinase preparations and extensively applied in the clarification of fruits juice, vegetables extracts, and wines. However, most of the reported fungal endo-polygalacturonases are active and stable under narrow pH range and low temperatures. In this study, an acidic endo-polygalacturonase (EPG4) was purified and characterized from a mutant strain of Penicillium oxalicum. The N-terminal amino acid sequence of EPG4 (ATTCTFSGSNGAASASKSQT) was different from those of reported endo-polygalacturonases. EPG4 displayed optimal pH and temperature at 5.0 and 60-70℃ towards polygalacturonic acid (PGA), respectively, and was notably stable at pH 2.2-7.0. When tested against pectins, EPG4 showed enzyme activity over a broad acidic pH range (>15.0% activity at pH 2.2-6.0 towards citrus pectin; and >26.6% activity at pH 2.2-7.0 towards apple pectin). The K_m and V_max values were determined as 1.27 mg/ml and 5,504.6 U/mg, respectively. The enzyme hydrolyzed PGA in endo-manner, releasing oligo-galacturonates from PGA, as determined by TLC. Addition of EPG4 (3.6 U/ml) significantly reduced the viscosity (by 42.4%) and increased the light transmittance (by 29.5%) of the papaya pulp, and increased the recovery (by 24.4%) of the papaya extraction. All of these properties make the enzyme a potential application in the beverage industry.