• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.37-45
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• 2013

The aim of this study was to investigate chemical characteristic of livestock compost in association with livestock manure types (poultry, cattle, swine, and mixed manure). The livestock compost was collected from local nonghyup branches on a si-gun level. Chemical composition (nutrients, heavy metals etc.) of the samples was analyzed and Pearson's correlation analysis was performed. Quality of most compost samples met the standard of fertilizer specifications. Poultry compost contains greater nutrients especially $P_2O$ (p-value<0.01) and $NH_4$-N (p-value<0.05). Meanwhile swine compost has higher concentration in water content (p-value<0.05) and heavy metals (p-value<0.01 for Cd, Cu and Zn). Overall, poultry compost was correlated positively with nutrients while swine compost has positive correlation with water content and heavy metals. We expect that the study results can provide base data for determining compost types and amount for crop production.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.285-289
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• 2011

In this study, lead-free $(K_{0.5}Na_{0.5+X})(Nb_{0.96}Sb_{0.04})O_3+0.2mol%La_2O_3+1.2mol%$ $K_4CuNb_8O_{23}$ (X= 0~0.025) ceramics were fabricated by normal sintering method at $1060^{\circ}C$ for 5 h. Microstructures, piezoelectric and dielectric properties of specimens were investigated with special emphasis in the influence of Na excess addition. The grain size of specimen was slightly decreased with increasing Na content. In the 2 [mol%] Na excess addition of NKNS ceramics, density, electromechanical coupling factor, piezoelectric constant and electromechancal quality factor of specimen were found to reach the optimum values of 4.25 [$g/cm^3$], 0.4357, 154.43 [pC/N] and 580, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.24-29
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• 2002

In this paper, the microstructure and the dielectric properties of Sr$\_$1-x/CaxTiO$_3$(0$\leq$x$\leq$0.2)-based grain boundary layer ceramics were investigated. The sintering temperature and time were 1420∼152 0$\^{C}$ and 4 hours in N$_2$ gas, respectively. The average grain size and the lattice constant were decreased with increasing content of Ca, but the average grain size was increased with increase of sintering temperature. The second phase foamed by the thermal diffusion of CuO from the surface leads to verb high apparent dielectric constant, $\xi$$\_$r/>50000 and low dielectric loss, tan$\delta$<0.05. X-ray diffraction patterns of Sr$\_$1-x/CaxTiO$_3$ exhibited cubic structure, and the peaks shifted upward and the peak intensity were decreased with x. This is due to the lattice contraction as Sr is replaced by Ca with a smaller ionic radius. The specimens treated thermal diffusion for 2hrs in 1150$\^{C}$ exhibited nonlinear current-voltage characteristic, and its nonlinear coefficient(a) was overt 7.

• Environmental Analysis Health and Toxicology
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• v.14 no.4
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• pp.155-163
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• 1999

Heavy metal accumulation in living organisms through food-wed can give serious damage on physiological responses for vital activities. The initiation of heavy metal supposed to begin from the bio-accumulation of plants. To establish basic data fur heavy metal contents in plants at the area without artificial contamination, both woody and herb plants at Mt. Kwang-Duk were studied. The content of heavy metals in various organs of plants were analyzed by ICP. The range of heavy metals in plants for Al, As, Cd, Co, Cr, Cu, Fe. Mn, Pb, Se and Zn were 1.019∼257.200ppm, O∼2.929ppm, 0∼0.079ppm, 0∼0.054ppm, 0.023∼3.007ppm, 0∼1.997ppm, 2.031∼148.500ppm, 1.069∼51.320ppm, O∼126.900ppm, 0.708∼4.927ppm and 0.846∼4.949ppm, respectively. The amount of heavy metals in plants are much less than that of soil except some species. In woody plants, it was detected that the metal contents of leaves were higher than that of stems especially in case of Al and Fe with statistical significance. There were significant differences between shoots and roots of herb plants in metal content of Al, Co and Fe. Those metals have more accumulated in roots comparing with shoots. Some species of plants had shown the difference tendency of heavy metal accumulation. Generally, most species had not exceeded over twice of mean value each other, and had various difference according to the kinds of heavy metals.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.11
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• pp.539-543
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• 2001

ln this paper, the $Sr_{l-x}Ca_xTiO_3(0\leqx\leq0.2)-based$ grain boundary layer ceramics were fabricated to measure dielectric properties with the sintering temperature and the thermal treatment time. The sintering temperature and time were $1420~15206{\circ}C$, 4hours, and the thermal treatment temperature and time of the specimen were $l150^{\circ}C$, 1, 2, 3hours, respectively. The structural and the dielectric properties were investigated by SEM, X-ray, HP4194A and K6517. The average grain size was increased with increasing the sintering temperature, but it decreased up to 15mo1% with increasing content of Ca. X-ray diffraction analysis results showed that all specimens were the cubic structure, and the main peaks were moved to right and the lattice constant were decreased with increasing content of Ca. The appropriate thermal treatment time and temperature of CuO to obtain dielectric properties of $\varepsilon_r>50000,\; tan \delta<0.05\; and \;\DeltaC<\pm10%$ were 2hrs and $l150^{\circ}C$, respectively.

• Journal of the Mineralogical Society of Korea
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• v.28 no.3
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• pp.209-220
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• 2015

The aim of this study was leaching valuable metal ions from mine waste rocks which were abandoned mine site using indigenous aerobic bacteria. In order to tolerate the the indigenous aerobic bacteria to the heavy metal ions they were repeatedly adapted in $CuSO_4{\cdot}5H_2O$ environment. As the repeated generation-adaptation progressed, the pH values of the growth-medium were gradually decreased. During bio-leaching experiments with indigenous aerobic bacteria raised in a heavy metal ion environment for 42 days, the pH of the leaching solution was decreased while increasing the adaptation period. The indigeous bacteria were much more active on the surface of Younhwa waste rocks which contained relatively few the chalcopyrite and Cu content than the Goseong mine waste rocks, and also the amount of Cu and Fe ions were leached more in the Younhwa sample(leaching rate of 92.79% and 55.88%, respectively) than the Goseong sample(leaching rate of 66.77% and 21.83%, respectively). Accordingly, it is confirmed that valuable metal ions can be leached from the mine waste rocks, if any indigenous bacteria which inhabits a mine environment site for a long time with heavy metal ions can be used, and these bacteria can be progressively adapted in the growth-solutions containing the target heavy metals.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.25-40
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• 2001

In order to investigate the degree of heavy metal pollution, 280 urban gully-pot sediments were collected from 13 localities in eastern part of Seoul. The uncontaminated stream sediments were also studied for comparison. A series of studies have carried out concerning the physicochemical characteristics of the sediments and the distribution of Cd, Co, Cr, Cu, Ni, Pb, and Zn. Total metal concentrations of gully-pot sediments and uncontaminated stream sediments were analyzed using acid extraction. After predigestion with $NHO_3$, the sample was digested with mixed acid ($NHO_3$-$HClO_4$). The gully-pot sediments were characterized by very high concentrations of Zn, Cu, Pb and Cr, indicating an anthropogenic contribution of these metals to the sediment chemistry Heavy metal concentrations in the gully-pot sediments were 1-329 times higher than the mean content of metals in the uncontaminated stream sediments, depending on the metals. In particular, the highest mean concentrations of Zn, Cu, Pb and Cr were noticed in the gully-pot sediments from Yeouido, Junggu, Junggu, and Dongdaemungu, respectively. The mean value of total Zn concentration in the business and commercial areas is 2-3.5 times higher than that in industrial areas. This suggests that Zn is mainly derived from automobiles (rubber of automobile tires). The mean concentrations of Cu and Cr are significantly high in the commercial and industrial areas, indicating that industrial activities may cause the accumulation of Cu and Cr in the sediments. The Pb level in gully-pot sediments is comparatively low, due to the use of unleaded gasoline in automobiles since 1987.

• Korean Journal of Environmental Agriculture
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• v.10 no.2
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• pp.119-127
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• 1991

In order to reveal the mechanism of heavy metal behavior in soils relating to factors such as soil pH, organic matter, C.E.C. and soil minerals influencing the activities of heavy metals, Cd, Cu and Zn were applied to soil columns filled with 8 different soils with adjusted soil pH to several levels between 3.0 to 11.0 and the amounts of adsorption and desorption of these heavy metals were measured. 1. At the adsorption maxima of three heavy metals(Cd, Cu and Zn) soil pH appeared to be near 6.0 regardless of properties of the 8 soils, and adsorption gradually decreased above and below pH 6.0. This phenomenon was the same in both heavy metal solutions and mixed solutions, and the mixed solution, containing three heavy metals, revealed slightly higher amounts of Cu adsorption and Cd adsorption. 2. It was also found that the adsorption of Cu and Zn by soils was positively correlated with C.E.C. and the organic matter of soils, respectively. However, the pH values showing maxima of heavy metal adsorption were negatively correlated with organic matter content by contrast with the correlation between the maxima and the C.E.C. values in soils. 3. The adsorption of Cu by soils markedly increased more with $Ca(OH)_2$ application than with NaOH application for soil pH adjusment. This was probably because of Ca effects in Cu precipitation in soils, in addition to the effect of the simple soil pH itself on Cu adsorption 4. It was also revealed that adsorbed Cu was hardly desorbed by $N-NH_4OAC$ solution from the Daejeong soil series compared to the Jeonbug and Yechun soil series. This was because the Daejeong soil series consisted of large amounts of expanding type Vermiculite minerals and also was high in C.E.C. and soil organic matter.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.314-318
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• 2000

To compare heavy metal phytoavailability in paddy soils near five abandoned mining areas, 4 different soil extractants such as 0.1M-HCl, $0.1M-HNO_3$, 0.05M-EDTA, and 0.005M-DTPA were used. Total acid digestion method $(H_2SO_4:HClO_4:HNO_3)$ was also employed to analyze heavy metal content in 30 paddy soils and brown rice. The rates of extracted heavy metal to total content were in the range of $12.1{\sim}39.1%$ for Cd, $20.5{\sim}45.5%$ for Cu, $10.6{\sim}30.7%$ for Pb, and $6.7{\sim}13.0%$ for Zn. 0.1M-HCl and $0.1M-HNO_3$ extractable both Cu and Pb were relatively less extracted at the high soil pH and extractable calcium site(Mine D) whereas 0.05M-EDTA and 0.005M-DTPA extractable Pb were strongly extracted at the same soils. In case of Cd, Cu, and Zn in soil, 4 types of extractable heavy metals and total content were highly correlated with each other. However, there were positive correlations between 0.1 M-HCl and $0.1M-HNO_3$ extractable Pb as well as between 0.05M-EDTA and 0.005M-DTPA extractable Pb, which were relatively similar extractants in chemical properties. The rates of heavy metals in brown rice to total contents in soils were in the order Zn>Cd>Cu>Pb. Specially, the rate of Cd, Pb, and Zn were lower at the highest level of soil pH and Ex. Ca. Both Cd and Zn in brown rice were positively correlated with those of all soil extractants. It was estimated that the solubility following to the plant uptake of Cd and Zn were higher than those of Cu and Pb considering relationships between all kinds of heavy metal contents in soil and those in brown rice.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.103-109
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• 1996

Mn(II)+succinate decreased the carotenoid formation of the yeast Phaffia rhodozyma, probably by scavenging $O_2$. When duroquinone (DQ), an internal and external $O_2$ generator, was added to medium, P. rhodozyma produced more amount of carotenoids. The increased carotenoid production was destroyed by oxygen radical (OR) scavengers, ascorbate+Cu(II) and dimethylsulfoxide. When sub-lethal concentrations of $H_2O_2$ , an external OR source, and antimycin, an internal OR inducer, were used, the effect of $H_2O_2$ on carotenoid formation and composition was less significant than that of antimycin. Addition of superoxide dismutase, an external OR remover, rescued cells from death caused by the high concentration of DO. In this condition, the yeast culture showed an increase in carotenoid content. Addition of DQ into P. rhodozyma culture in the stationary phase did not increase carotenoid production. Therefore, carotenoid formation was stimulated by internal ORs in the growing yeast. It was probably due to release of catabolite repression on carotenogenesis in the yeast. Aeration was important for carotenoid production but was not as effective as the internal OR producer, DQ.