• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.179-185
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• 2009

In this research, the removal capacity of Cr(VI) by the reused powdered wastes (RPW) containing aluminium oxides was studied. As a pre-treatment process for the preparation of calcined wastes, calcination was conducted at $550^{\circ}C$ to remove organic fraction in the raw wastes. In order to study the adsorption trend of Cr(VI) ions from aqueous solutions, the pH-edge adsorption, adsorption kinetic and adsorption isotherm were investigated using a batch reactor in the presence of four different background electrolytes($NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-},\;PO_4\;^{3-}$). Cr(VI) adsorption was greatly reduced in the presence of $SO_4\;^{2-}$ and $PO_4\;^{3-}$ over the entire pH range. Meanwhile the inhibition effect by $NO_3\;^-$ and $CO_3\;^{2-}$ was relatively lower than that by $SO_4\;^{2-}$ and $PO_4\;^{3-}$. Cr(VI) adsorption was maximum around pH 4.5 in the presence of $NO_3\;^-$ and $CO_3\;^{2-}$. As the concentration of background electrolytes increased, Cr(VI) adsorption decreased. This result mightly suggests that adsorption between the surface of RPW and Cr(VI) occurs through outer-sphere complex. Cr(VI) adsorption onto the RPW was well described by second-order kinetics. From the Langmuir isotherm at initial pH 3, the maximum adsorbed amount of Cr(VI) onto the RPW was 11.1, 10, 3.3, 5 mg/g in the presence of $NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-}$, and $PO_4\;^{3-}$, respectively.

• Clean Technology
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• v.21 no.3
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• pp.153-163
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• 2015

The effects of H₂O and residue SO₂ in flue gases on the activity of the Fe/zeolite catalysts for low-temperature NH₃-SCR of NO were investigated. And the addition effect of Mn, Zr and Ce to Fe/zeolite for low-temperature NH₃-SCR of NO in the presence of H₂O and SO₂ was investigated. Fe/zeolite catalysts were prepared by liquid ion exchange and promoted Fe/zeolite catatysts were prepared by liquid ion exchange and doping of Mn, Zr and Ce by incipient wetness impregnation. Zeolite NH₄-BEA and NH₄-ZSM-5 were used to adapt the SCR technology for mobile diesel engines. The catalysts were characterized by BET, X-ray diffraction (XRD), SEM/EDS, TEM/EDS. The NO conversion at 200 ℃ over Fe/BEA decreased from 77% to 47% owing to the presence of 5% H₂O and 100 ppm SO₂ in the flue gas. The Mn promoted MnFe/BEA catalyst exhibited NO conversion higher than 53% at 200 ℃ and superior to that of Fe/BEA in the presence of H₂O and SO₂. The addition of Mn increased the Fe dispersion and prevented Fe aggregation. The promoting effect of Mn was higher than Zr and Ce. Fe/BEA catalyst exhibited good activity in comparison with Fe/ZSM-5 catalyst at low temperature below 250 ℃.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.291-295
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• 2010

A novel bacteriocin produced by Streptococcus parauberis Z49 strain was characterized and efficiently extracted from fermented cultures by use of aqueous two-phase systems. The nisin-like bacteriocin, which was active even after a heat treatment at $121^{\circ}C$ for 15 min and in the broad pH range from 2 to 12, showed inhibition of bacterial growth of Micrococcus luteus, Lactobacillus spp., Lactobacillus fermentum, Enterococcus faecium, Listereia monocytogenes, and Pseudomonas fluorescens. Optimal conditions of PEG 600/$Na_2SO_4$ aqueous two-phase systems for the simple and rapid extraction of a novel bacteriocin were determined to be PEG 600 15%, $Na_2SO_4$ 30%, and NaCl 8%, where the bacteriocin was concentrated in PEG layer.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.328-336
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• 1993

This study was conducted to investigate sensitivity of tree seedlings to $SO_2$. Visible injury symptoms and changes of ethylene production were investigated in tree seedlings with the fumigation of $SO_2$ in gas chamber 4 hours a day for six days. The symptoms of visible injury did not appear below 0.5ppm level of $SO_2$ exposure but a change of visible injury with the passage of time appeared at 1.5 and 2.5ppm in all seedlings. With the higher the concentration and/or the longer exposure of $SO_2$ the visible injury symptoms on leaves increased in all seedlings. The sensitivity of seedlings to $SO_2$ was the highest in Liriodendron tulipifera followed by Pinus strobus, Ginkgo biloba, Pinus densiflora and Pinus koraiensis. The amount of ethylene production was more at 1.5 and 2.5ppm of $SO_2$ exposure than at 0.5ppm and the peak time of it came faster at higher levels. The amount of ethylene production was significantly different among tree seedlings. It showed a higher at production of ethylene in Liriodendron tulipifera compared to Ginkgo biloba and the ethylene production of Pinus trees to $SO_2$ were the highest in Pinus strobus followed by Pinus densiflora and Pinus koraiensis. In needle of Pinus strobus the ethylene production increased with the increasing rate of visible injury until the injury rate of 40-50% and than decreased with the increasing rate of visible injury since the rate of 50%.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.1-10
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• 2012

This study was carried out to provide basal information on factors effected the decline of Pinus thunbergii by analysisof, the content of chlorophyll, and acid deposition through stepwise regression analysis. pH in throughfall at industrial area was 4.65 in the spring and 4.72 in the fall. On the contrary, pH at rural area was measured 5.32 in the spring and 5.34 in the fall. EC of rain fall at industrial area was $262.30{\mu}s$, However, there was $47.72{\mu}s$ at control area. Of anions, the concentration of ${NO_3}^-$ was $52.13mg/{\ell}$ at industrial area and $37.85mg/{\ell}$ at area. The concentration of ${SO_4}^{2-}$ was $57.89mg/{\ell}$ at industrial area and $36.21mg/{\ell}$ at area. Of the concentration of leaf chlorophyll in Pinus thunbergii, chlorophyll a was 0.2378 but control area was 0.4378. Also the content of chlorphyll b was 0.2097 and control area was 0.2345. The degree of decline of Pinus thunbergii forest was 2.97 at industrial area and 1.20 at area. We carried out a correlation analysis between the degree of decline and the concentration of ions, $SO_2$, and $NO_2$ in Pinus thunbergii forest. As a result, there was a negative correlation (r=-0.8672) between rain acids, and a positive correlation between $SO_2$ concentrations (r=0.8924) and between $NO_2$ concentrations (r=0.8428) in air. The correlations among acid depositions at level of 1% were pH (r=-0.8672), ${NO_3}^-$(r=0.6996), ${SO_4}^{2-}$(r=0.8497), $SO_2$ (r=0.8924), and $NO_2$ (r=0.8428).

• Journal of agriculture & life science
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• v.46 no.6
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• pp.51-57
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• 2012

This study was carried out to analyze chemical compositions of the fog water of a forest area, Jinju and to provide basic information for establishing measures on the acid fog water of forest area. The results are as follows: The pH of fog water was 4.3 in 2010, whereas the pH in 2011 was 4.0. The electrical conductivity of the fog water was $477.2{\mu}s$ in 2010, and $562.7{\mu}s$ in 2011. Among the anions, the concentration of $NO^{3-}$ was the highest, which recorded 267.1 mg/L in spring season and 279.1 mg/L in summer season, followed by $SO{_4}^{2-}$ at the concentration of 177.2 mg/L in spring season and 198.6mg/L in summer season. In autumn and winter, the concentration of $NO^{3-}$ was highest as 217.7 mg/L and 237.9 mg/L, respectively and followed by $SO{_4}^{2-}$, which concentration was 164.2 mg/L in autumn season and 190.1 mg/L in winter season (p<0.05). Among the cations, the concentration of $Ca^{2+}$ was 221.3 mg/L in spring and 233.7mg/L in summer, followed by $Na^+$ at 125.1 mg/L in spring season and 131.7 mg/L in summer In autumn and winter, the concentration of $Ca^{2+}$ was highest at 196.8 mg/L and 198.8 mg/L, followed by $Na^+$ at the concentration of 97.1 mg/L in autumn and 117.2 mg/L in winter (p<0.05). The pH of the fog rain that causes acid mist showed the correlation with $Ca^{++}$ (1% of level), $EC(r=-0.9861^{**})$, $NO^{3-}$ ($r=-0.9677^{**}$), and $SO{_4}^{2-}$ ($r=-0.9510^{**}$). The regression equation on the factors affecting the generation of acidic fog rain was estimated to be a $Y(pH)=6.4627+0.9723X_2(EC)+0.9364X_4(NO_3{^-})+0.9044X_5(SO{_4}^{2-})+0.8049X_{10}(Ca^{2+})+0.6709X_8(K^+)\;(r^2=0.8787)$.

• YAKHAK HOEJI
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• v.36 no.6
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• pp.538-547
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• 1992

Optimal synthetic condition of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. Barium chloride and magnesium sulfate were utilized as reactants in order to prepare barium sulfate in this study. It was found that optimum temperature range of reactant solutions was $60{\sim}100^{\circ}C$ and the optimum concentration range of the reactant solutions was $10{\sim}17.3%$ and $10{\sim}20%$ respectively, on the viewpoint of yield and bulkiness. The optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum reacting time range was $15{\sim}20$ minutes. The optimum drying temperature range was $110{\sim}130^{\circ}C$ from the viewpoint of yield, but it was $90{\sim}110^{\circ}C$ on the basis of bulkiness. Apparent viscosity of barium sulfate suspensions dispersed in various concentrations of Na. CMC was measured by using Brookfield synchrolectric viscometer model LVT, the relative equation, log ${\eta}_{sp}=A+B.{\phi}$ was examined and the equation was found to agree fairly well. 1 w/v% Na. CMC aqueous solution and 0.1 volume fraction of $BaSO_4$ powder were optimum in the preparation of $BaSO_4$ suspension showing highest viscosity at infinite shearing.

• Journal of the Korean institute of surface engineering
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• v.52 no.5
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• pp.251-257
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• 2019

Fe-9Cr-2W steels were corroded at $600-800^{\circ}C$ for up to 100 hr in ($Na_2SO_4-K_2SO_4-Fe_2O_3$)-($CO_2-0.3%SO_2-6%O_2$) mixed gas. The poor condition samples formed thick oxide scales that consisted primarily of $Fe_2O_3$ as the major oxide and $Fe_3O_4$, FeO as the minor one through preferential oxidation of Fe. Fe-9Cr-2W steels corroded fast, forming thick and non-protective scale. The scale divided into the outer and inner layer, which consisted of the outer Fe-O layer and the inner (Fe,Cr)-O layer containing some (Fe,Cr)-S.

• Ocean and Polar Research
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• v.31 no.4
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• pp.297-304
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• 2009

We investigated the response of the westerly winds over the Southern Ocean (SO) to glacial boundary conditions for the Last Glacial Maximum using the CCM3 atmospheric general circulation model. In response to glacial boundary conditions, the zonally averaged maximum SO westerly winds weakened 20-35% and were displaced toward the equator by 3-4 degrees. This weakening of the SO westerly winds arose from a substantial increase in mean sea level pressure (MSLP) in the southern part of the SO around Antarctica relative to the northern part. The increase in MSLP around Antarctica is associated with a marked temperature reduction caused by an increase in sea ice cover and ice albedo feedback during the glacial time. The weakened westerly winds in the SO and their equator-ward displacement might play a role in reducing the atmospheric $CO_2$ concentration by reducing upwelling of the carbon rich deep water during the glacial time.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.53-59
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• 2005

The effect of various stressors such as reductant ascorbic acid, signalling molecules (salicylic acid and methyl jasmonic acid), heavy metals $(NiCl_2,\;and\;MnSO_4)$ and NaCl on the glutathione peroxidase (GPX) activities and isoenzyme expression patterns were investigated in rice seedling roots. Total GPX activity increased according to the increase of ascorbic acid concentration. Prominent enhancement of GPX1 isozyme due to ascorbic acid contributed to the increase of total GPX activity. GPX showed different reactivity toward salicylic acid and methyl jasmonic acid. GPX activity increased at 0.1 mM salicylic acid, and then decreased thereafter. However, GPX increased gradually in a methyl jasmonic acid concentration-dependent manner, and 3 fold increase of GPX activity was found at 1 mM methyl jasmonic acid. Moreover, GPX1 isozyme increased according to the increase of salicylic acid, while GPX1 isozyme decreased according to the increase of methyl jasmonic acid. When metal ions were treated, GPX activity increased considerably according to the increase of $NiCl_2$ concentration, however, GPX activity increased about 2 fold at 0.5 mM $CuSO_4$ and then decreased. Enhancement of GPX1 isozyme contributed to the increase of total GPX activities in $NiCl_2-treated$ and $MnSO_4-treated$ rice seedlings. Total GPX activity increased 1.7 fold in response to 300 mM NaCl. Especially GPX2 isozyme showed gradual increase according to the increase of NaCl concentration.