• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.33-43
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• 2002

Mineral composition and chemical properties of Hwangto (reddish residual soil) that used in feeding of cattles at Iksan, Jeollabuk-do, Korea were examined according to particle size separation such as gravel, sand, silt, coarse clay and fine clay. Mineral composition analyses reveal that gravel and sand are mainly composed of quartz and feldspars and that kaolin mineral and illite are dominant in clay and silt. Iron oxides are mainly included in fine clay. According to chemical analyses of major elements, Al, Fe and $H_2O$ contents are increased with decreasing of particle size. This trend well agrees with increase of clay minerals in smaller particles, Chemical analyses of trace elements indicate that contents of Zn, Rb, Sr, Ba, Pb significantly differ with particle sizes. Ba and Sr are included in feldspars since these elements are abundant in sand containing abundant feldspars. Pb and Sm are abundant in sample before particle size separation, but the contents are significantly decreased after separation. Therefore, most of these elements appear to be existed as removable phase. Nb, La, Th, Ce are more abundant in silt. The contents of all the other trace elements tend to be increased in smaller particles containing more clay minerals. The contents of changeable cations and teachable elements in acid and alkali solutions are high in clay samples. All the above results indicate that using the portion of smaller particle of Hwangto for livestock feed rather than bulk Hwangto can improve cation exchangeable capacity, ion leaching capacity and sorption properties.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.94-99
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• 2004

The activities of enzymes that act on oxygen derivatives in Rhodobacter sphaeroides D-230 were investigated under various culture conditions. Intracellular SOD activity from the cells grown in aerobic or anaerobic culture conditions was highest at pH 7.0 and pH 8.0, respectively. On the other hand, extracellular SOD activity was highest at pH 6.0. Catalase activity was highest at neutral pH in both cases. Growth of R. sphaeroides D-230 in aerobic or anaerobic culture conditions was inhibited by methyl viologen. As R. sphaeroides D-230 was cul-tured aerobically, SOD activity was increased about 2-fold by addition of iron ion. But $Mn^+2$ had little effect on the SOD activity of R. sphaeroides D-230 grown in aerobically. NaCN, the inhibitor of Cu$.$Zn-SOD, did not inhibit SOD activity. But, $NaN_3$, the inhibitor of Mn-SOD, inhibited SOD activity in anaerobic cultures con-dition. Therefore, R. sphaeroides D-230 produce Mn-SOD in anaerobic condition, although Fe-Sod is produced in aerobic condition. The activity of catalase was induced by methyl viologen, however, extremely inhibited by NaCN and $NaN_3$.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.251-259
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• 2005

In order to characterize the influence of the reaction-site density on the cathodic polarization property of LSCF, we chose the porosity of LSCF as a main controlling variable, which is supposed to be closely related with active sites for the cathode reaction. To control the porosity of cathodes, we changed the mixing ratio of fine and coarse LSCF powders. The porosity and pore perimeter of cathodes were quantitatively analyzed by image analysis. The electrochemical half cell test for the cathodic polarization was performed via 3-probe AC-impedance spectroscopy. According to the investigation, the reduction of oxygen at LSCF cathode was mainly controlled by following two rate determining steps; i) surface diffusion and/or ionic conduction of ionized oxygen through bulk LSCF phase, ii) charge transfer of oxygen ion at cathode/electrolyte interface. Moreover, the overall cathode polarization was diminished as the cathode porosity increased due to the increase of the active reaction sites in cathode layer.

• Journal of Conservation Science
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• v.25 no.4
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• pp.399-409
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• 2009

Outdoor iron artefacts are easily corroded by affection of environmental pollutants directly. Especially they need to be removed $Cl^-$ ions, but outdoor iron artefacts are excluded for desalination owing to their special features. Therefore this study contains the conservation processes of an iron stele of the Joseon Dynasty as the sample as well as desalination experiments that were carried out the desalting method using spill pads and the immersion desalting method together in order to compare. Desalting methods were compared by analyses such as an optical and metallurgical microscope, SEM-EDS, pH meter, Ion Chromatography and X-ray diffraction. As a result of the analysis, the optical and metallurgical microscopy show that the corrosion products are constituted by the layers and the metallurgical microstructure is a white cast iron. The SEM-EDS results of corrosion products detected mainly Fe, O, and especially Cl upto 2.48wt%. The results of pH and anion analysis for the washing solution, the desalting method using spill pads shows the similar effect to the immersion desalting method. As a result of XRD analysis before and after desalting corrosion products, goethite, magnetite, lepidocrocite and akaganeite are detected before desalting, but akaganeite is not detected after desalting at the desalting methode using spill pads, which indicates to have an effect on desalination. Therefore the results show that the desalting method using spill pads has an effect on desalination similar to the immersing desalting method.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.103-108
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• 2011

$Li_2MnSiO_4$/C was synthesized by solid state reaction and solution synthesis with sucrose for carbon source. The X-ray diffraction patterns of solid state reaction indicates small amount of impurities. By FE-SEM and HR-TEM, solution synthesis comprised several tens of nanometer comparing to 500~600 nm of $Li_2MnSiO_4$/C prepared by solid state reaction. The $Li_2MnSiO_4$/C prepared by solution synthesis show better electrochemical performance than solid state reaction. The first charge-discharge capacity are 236, 189 mAh/g respectively by solution synthesis. But its cycle performance was poor as yet and its capacity retention was 62% after 10 cycles.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.439-449
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• 2017

The cause of yield reduction in a collector well, which is located in Anseong-cheon watershed in Kyunggi province, is studied by using aquifer sediments' composition and hydraulic conductivity near four horizontal wells, no. 1, no. 4, no. 6, and no. 7 wells. During test-pumping periods, groundwater yield is reduced with a trend of $12.4m^3/d/d$ at no. 1, $2.3m^3/d/d$ at no. 4, $24.4m^3/d/d$ at no. 6, and $187.3m^3/d/d$ at no. 7 and no. 7 well shows the biggest reduction. The sediments along no. 7 horizontal well have low hydraulic conductivity and high coefficient of uniformity ($C_u$), and a deviation of $C_u$ along the well is also large. This characteristics can bring the fine particles' movement and make the openings filled. Additionally, high iron ($Fe^{2+}$) content results in a precipitation of iron hydroxides during pumping or injection and they can produce a clogging in sediments. In the future study, the analysis of physical and hydrochemical changes through a long-term pumping procedure will give a more exact interpretation for the cause of yield reduction.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.239-246
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• 2012

This study was performed to investigate the removal characteristics and mechanism of heavy metals using pellet-type ceramics(ZS ceramics), in which natural zeolite was mixed and calcined with converter slag. The optimal calcination temperature range was measured to be $600{\sim}800^{\circ}C$. The calcination time had little effect on the removal of heavy metal in acid wastewater. The adequate dose of ceramics was shown to be 2~5% for removal of heavy metals in acid wastewater. The maximum removal capacity of ZS ceramics for heavy metals were observed to be Al 84.7 mg/g, Cd 37.3 mg/g, Cr 81.7 mg/g, Cu 55.6 mg/g, Fe 57.2 mg/g, Mn 32.1 mg/g, Ni 38.0 mg/g, Pb 71.6 mg/g, Zn 46.3 mg/g. The pH played a pivotal role in the removal of heavy metals by ZS ceramics. The analysis results of mechanism exhibited that the ZS ceramics could act as a multi-functional ceramics for removal of heavy metals in acid wastewater by adsorption, ion-exchange, or precipitation.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.304-309
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• 1999

Two Lectins, designated FVL-1 and FVL-2, were isolated and purified from the fruiting bodies of edible mushroom Flammulina veluripes using ammonium sulfate fractionation, ethanol treatment, DEAE-TOYPEARL ion-exchange column chromatography, and TSK-Gel HW-55F column chromatography. Specific activity increased 18 folds for FVL-1 and 7.9 folds for FVL-2 from ethanol treated sample. SDS-PAGE of FVL-1 and FVL-2 gave apparent molecular mass of 10.6 kDa and 37 kDa, respectively. FVL-2 agglutinated all type of human erythrocytes (A, B, AB, and O). However, FVL-1 agglutinated more human erythrocyte type O than type A, B, and AB. The hemagglutination activities of the FVL-1 were effectively inhibited by bovine submaxillary and porcine stomach mucins(BSM and PSM), fetuin, asialofetuin and cations, such as $Cu^{2+}$, $Mg^{2+}$, $Ca^{2+}$, $Mn^{2+}$ and $Fe^{2+}$. However, FVL-2 was not inhibited by any cations. The hemagglutination activities of the two lectins were not inhibited by the sugar, such as lactose, galactose and sugar derivatives. FVL-1 and FVL-2 were stable at pH $5{\sim}11$ and pH $4{\sim}7$, respectively. FVL-1 was stable below $55^{\circ}C$ and FVL-2 was below $45^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.330-338
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• 2012

During 10 days germination of perilla seeds for sprouts preparation, the changes of proximate composition and antioxidant activities were monitored, and the inhibitory effect of sprouts extracts on perilla oil oxidation was also studied. The moisture content in seeds(2.9%) was increased to 9.2% in sprouts at 10 days while crude ash content wasn't significantly. The crude fat and protein contents were reduced from 46.8% and 20.7% in seeds to 18.2% and 18.3% in sprouts, respectively, but reducing sugar and fiber contents increased from 2.2% and 14.8% to 12.8% and 22.4%, respectively. Compared with perilla leaf, sprouts at 10 days contained more fat, carbohydrate, reducing sugar, and fiber while less moisture, ash, and protein. Antioxidant activities during germination were increased and reached to maximum at 8 days in which Trolox equivalent antioxidant capacity(TEAC) based on DPPH and ABTS radical scavenging were 133.1 and 136.8 Trolox eq. mmol/kg, respectively, and ferric ion reducing power(FRAP) was 399.3 Fe(II) eq. mmol/kg. Polyphenol content(19.2 g/kg) was maximum at this stage, too. Perilla leaf showed similar TEAC but higher FRAP than the sprouts. When methanol extract of sprouts at 8 days was added to perilla oil, the oil oxidation was delayed in dose dependent manner. The induction time for oxidation was extended about 2.8 times by adding 2.5%(w/w) extract, that is, from 1.67 hr(control) to 4.62 hr. This induction time corresponded to 38% level of that of perilla oil containing 2.5% BHT.

• Resources Recycling
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• v.24 no.5
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• pp.33-39
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• 2015

A basic study was conducted to effectively recover nitric acid from a waste solder stripper by diffusion dialysis using anion exchange membranes. The effects of flow rate, flux ratio, nitrate concentration, and metallic ion types and concentration on the recovery percentage of nitric acid were investigated. The recovery percentage of nitric acid was decreased with the increase of flow velocity. But the recovery percentage of nitric acid was increased as the increase of flux ratio(W/F) and showing a recovery percentage of nitric acid of about 99% at a flux ratio of 1.5 or more. As the increase of nitric acid concentration in feed solution, the recovery percentage of nitric acid was increased up to 3.0M, but in case of greater than 3.0M, the recovery percentage gradually was decreased. Leakage percentage of metallic ions through the membrane were in the order of Pb, Na and Cu but Fe and Sn did not leakaged. As a result of diffusion dialysis using real waste solder stripper at a flow rate of $0.9L/hr-m^2$, W/F = 1.3, a recovery percentage of nitric acid of approximately 94% was gained.