• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.68-77
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• 2009

For the reservoir sediment highly contaminated with total Cr, Pb, and Cd, the applicability of electrokinetic remediation method was evaluated. Also, BCR sequential extraction method was adopted to compare the heavy metal speciation in between before and after electrokinetic reaction that is operated under constant current condition for the sediment. After reaction, total Cr and Pb moved toward the direction of anode, while Cd tended to cathode and stayed highest in the midst of sediment specimen. From the BCR sequential extraction analysis, it was known that for total Cr and Pb the residual fraction that showed high fraction before reaction decreased and changed to the oxidation fraction. On the other hand, for Cd the fraction of exchangeable/carbonate that dominated most fractions before reaction changed to the residual and oxidation fractions.

• 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 $NaN_3$.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.20-25
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• 1996

This survey was conducted to investigate the chemical properties of soils cultivated medicinal plants. The soils were collected at 254 sites(Angelica gigas : 81, Astragalus membranceus : 38, Platycodn glandiflorum : 36, Paeonia albiflora : 34, Codonopsis lanoceolata : 32, Ligusticum chuanxiong : 17. Bupleurum falcatum : 16, respectively) throughout the country by 0-15cm depth. The chemical properties of soils were pH 5.6, O.M 3.0%. Av.$P_2O_5$ : 405 mg/kg, Ex.K : $0.67cmol^+/kg$, Ex.Ca : $6.3cmol^+/kg$, Ex.mg : $1.6cmol^+/kg$. The percentage distribution of pH on the basis of soil sample numbers were much more at the 5.1-6.0 range than any other ranges, especially those of below pH 6.0 were 83-91% for Angelica gigas, Platycodn glandiflorum and Codonopsis lanoceolata. The distribution of OM and Av.$P_2O_5$ in soils were much at the 2.1-4.0% and above 500mg/kg ranges, respectively. And the content of those in soils cultivated with Platycodn glandiflorum were lower than any other medicinal plants. The distribution of exchangeable cations in soils were much at the 0.2-0.8, 2.1-4.0 and $0.5-2.0cmol^+/kg$ of Ex.K. Ca and mg. respectively, and the contents were higher in soils cultivated Astragalus membranceus. and lower in soils cultivated Platycodn glandiflorum and Codonopsis lanoceolata than any other samples.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.140-147
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• 2011

We studied the influence of livestock waste leachate on oxidative damage and antioxidative responses in poplar clones in August which increase the demand of antioxidants because of high temperature and high light during this period. We measured ion leakage, antioxidant enzyme activities (APX, GR), and carotenoid contents. Oxidative damage and antioxidative responses by treated livestock waste leachate in poplar clones showed various results. We divided poplar clones into three groups using the criteria based on ion leakage which represent cell damage induced oxidative stress. Eco 28, 62-10, Bonghwa1 and Dorskamp belonged to the first group in which the cell damaged level was lower than that of the control. The results suggest that this group augmented for demand of antioxidative in summer because high concentration of nitrogen induced by treatment of live stock wastes acted as environmental stress. Consequently, they failed to keep up the homeostasis of reactive oxygen species. The second group in which the cell damaged level was similar to that of the control was Suwon, 72-30 and 72-31 clones. Finally, 97-18 clone belonged to the third group in which the cell damaged level was lower than that of the control group. In this case, nitrogen treated by livestock waste leakage decreased oxidative stress. 97-18 clone was the clones with the least damage in summer oxidative stresses treated by livestock waste leakage. These results suggest that the high concentration nitrogen due to the livestock waste leakage can act differently upon the clones. We speculate that the added oxidation damage in the summer (growing season) may have an effect on the total fresh weight and also influence the purification ability for livestock waste leakage. However, further studies are needed for the confirmation.

• Journal of the Korean Chemical Society
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• v.41 no.1
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• pp.12-17
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• 1997

The critical micelle concentrations(CMC*) and the counterion binding constants(B) in a micellar state of the mixed surfactant systems of sodium dodecylsulfate(SDS) with sodium dodecylbenzenesulfonate(DBS) at 25℃ in pure water and in aqueous solutions of n-butanol were determined as a function of α1 (the overall mole fraction of SDS) by the use of electric conductivity method. Various thermodynamic parameters(Xi, γi, Ci, aiM, β, ΔHmix and ΔGm0 for the micellization of SDS/DBS mixtures were calculated and analyzed by means of the equations derived from the nonideal mixed micelle model. The effect of n-butanol on the mixed micellization of SDS/DBS mixtures have been measured and analyzed by comparing the values of the thermodynamic parameters in pure water with those in aqueous solutions of n-butanol(0.1 M, 0.2 M, and 0.3 M).

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.161-164
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• 1979

The effect of acidity and the metal surface area of the Pd loaded zeolite catalysts; prepared from $Ca^{2+}-,\;La^{3+}-,\;NH_4^+-$exchanged Y and dealuminated HY was studied for the reaction of n-butane. The amount of strong acid site determined by the temperature programmed desorption of ammonia increased in the order NaY < CaY < LaY. Total amount of acid site decreased with increasing degree of dealumination, but the portion of strong acid site increased with increasing $SiO_2/Al_2O_3$ ratio. The effective metal surface area determined by the CO adsorption technique was large for those zeolite catalysts having strong acidity. It was found that conversion of n-butane was strongly dependent on the acidity and the effective metal surface area of the catalysts. The fact that the conversion of n-butane was proportional to the effective metal surface area suggests that the dehydrogenation by metallic component is the primary step in the reaction of n-butane.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.81-89
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• 2012

This study was investigated to evaluate the effects of fertilizer application of surface and broadcast for rice culture on the soil chemical, physical, and microbial properties as well as growth and yield of rice. The application was made with 'Dongjin 1' rice at Jeollanam-do Agricultural Research & Extension Services from 2008 to 2010. Soil organic matter and cation concentrations were increased by surface and broadcast applications, respectively. Plots treated by surface application tended to be higher seasonal N-mineralization rate in the organic fertilizer and seasonal soil organic matter than those of broadcast application. Soil physical properties seemed to be improved by the broadcast application, and soil microbial properties were increased by the surface application. Surface application increased 5% of rice yield compared to that of broadcast.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.556-562
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• 2005

This study was performed to evaluate effects of pH and heavy metals on soil pollution in 167 sites of Gangwon-do. The overall pH range of soils was 4.3~8.4 The average soil pollution of Cd was 0.089 mg/kg (0.000~3.493 mg/kg), Cu 3.093 mg/kg (0.078~60.263 mg/kg), Pb 4.74 mg/kg (0.01~38.08 mg/kg), Hg 0.054 mg/kg (0.002~1.050 mg/kg), and As 0.971 mg/kg (0.031~77.051 mg/kg), but $Cr^{6+}$ was not detected in these soils. The average concentration of heavy metals in these soils was acceptable under the preliminary standard of soil preservation acts in Korea.

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.61-66
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• 2005

In order to make submicron cell for spin-injection device, lift-off method using Pt stencil and wet etching was chosen. This approach allows batch fabrication of stencil substrate with electron-beam lithography. It simplifies the process between magnetic film stack deposition and final device testing, thus enabling rapid turnaround in sample fabrication. Submicron junctions with size of $200nm{\times}300nm$ and $500nm{\times}500nm$ 500 nm and pseudo spin valve structure of $CoFe(30{\AA})/Cu(100{\AA})/CoFe(120{\AA}$) was deposited into the nanojunctions. MR ratio was 0.8 and $1.1{\%}$, respectively and spin transfer effect was confirmed with critical current of $7.65{\times}10^7A/cm^2$.

• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.271-279
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• 2015

The critical micelle concentration (CMC), the counter ion binding constant (B) and the aggregation number (N^* ) for the mixed micellization of sodium dodecanoate and sodium n-octanoate as two anionic surfactants have been investigated by means of electric conductivity and light scattering. As its experimental results are found to be deviated from ideal mixed model, thus two different kinds of regular solution models such as Rubingh and Motomura are used for interpreting our experimental data. The stability of the mixed micelles has been confirmed from the negative values of the standard Gibbs energy of mixed micellization ΔG^micel,0 over all compositions and the measured values of ΔG^micel,0 agreed with the theoretical ones within the experimental error.