• The Journal of Engineering Geology
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• v.17 no.2 s.52
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• pp.187-196
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• 2007

The Dalseong acid mine drainage were studied focused on the characters of schwertmannite that controls geochemistry of the stream. Besides chemical analysis of stream water, particle size analysis, XRD SEM and TEM were performed on precipitates of streams and on wasted metalliferous ores. The AMD discharged from the abandoned mine reveals a decrease of pH and EC downward stream. Euhedral sulfur occurs as equigranular aggregates on the altered pyrite while fine acicula goethite coalesces to form cross, star, or starfish-like shapes. Water chemistry plotted on the Eh-pH diagram shows that schwertmannite and ferrihydrite are stable phases. Reddish brown precipitates consist of mostly schwertmannite with less goethite, whereas yellowish brown precipitates are composed of geothite with less schwertmannite. The particle size of precipitates ranges $d(0.1)\;0.861{\mu}m{\sim}3.769{\mu}m,\;d(0.5)\;3.984{\mu}m{\sim}15.255{\mu}m,\;and\;d(0.9)\;9.875{\mu}m{\sim}56.726{\mu}m$. Schwertmannite is characterized by equigranular spheric form. Pincushion or spicule with 100nm width and $200{\sim}300nm$length form on schwertmannite sphere with radial growth patterns. It is highly probable that reddish or yellowish brown precipitates formed in many AMDs may contain schwerhnannite. Because it can serve as sink for removing heavy elements by adsorption in AMD system, there is a need to correctly identify schwertmannite in precipitates and to characterize its phase stability.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.351-357
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• 1987

A laboratory experiment was conducted to find out the effect of organic fertilizer as Bio-com$^{(R)}$ on the changes of pH and Eh values, gas evolution, ammonification and nitrification, and microbial population with farmer's compost and refused mushroom compost in submerged paddy condition. The results obtained are summarized as follows: 1. Application of compost and refused mushroom compost was increased the pH values than that of NPK alone. Organic fertilizer of Bio-com$^{(R)}$ showed the same results of the farmer's compost or refused mushroom compost. 2. Population of soil microbes as bacteria, actinomycetes and fungi was increased by application of compost, refused mushroom compost and Bio-com$^{(R)}$. Moreover, the results were pronounced more with the addition of NPK. 3. The application of Bio-com$^{(R)}$ was effected to the increase of the amount of $NO_3-N$ and the rate of nitrification than NPK, farmer's compost or refused mushroom compost. 4. The amounts of evolved gases as $CH_4$, $CO_2$, and $N_2O$ were not much differed with application of kinds of compost and NPK, but little increasing tendency was observed in application of NPK than that of NPK+kinds of compost.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.35-40
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• 1997

This study was conducted to investigate methane emission under different rice cultural practices in paddy soil (Jeonbug Series, occurring on fluvio-alluvial plain). The rates of application of fresh rice straw were 5,000kg/ha in combination with 110 and 160kg N/ha as chemical fertilizer. The methane emission among the rice cultural practices was in the order of transplanting cultivation, direct seeding on flooded surface and direct seeding on dry paddy field. The average methane flux was $10.27mg/m^2/h$ in direct, seeding on dry paddy field and $24.1mg/m^2/h$ in transplanting cultivation. The diurnal variation of methane emission at heading stage was high from 9 a.m. till 7 p.m. and the methane emission rate was highly correlated with air temperature fluctuation and soil Eh. The seasonal change of methane flux was high from ear formation stage to heading stage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.171-180
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• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.514.3-515
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• 1986

λP$_{L}$ promoter와 Infiuenza virus의 NS1 Structural gene이 있는 pASl EH801 plasmid를 E. coli host N5' 과 AR120에 각각 transformation하여 온도와 nalidixic acid로 각각 induction 하여 보았다 N5151의 경우, O.D.600 1.2에서 42$^{\circ}C$로 induction하였을 때 maximum productivity를 보였으며 AR120의 경우는 O. D. 600 1.2, 37$^{\circ}C$, 40$\mu\textrm{g}$ nalidixic acid/$m\ell$ induction 하였을 때 maximum yield를 보여주었다. 이때 pH, DO, temperature, $O_2$%, $CO_2$%를 A/D converter통해 computer에 연결시켜 data acquision을 한 결과, 접종 후 ON-line induction이 가능함을 알 수 있었다.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.82-89
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• 1984

These studies were carried out to investigate the effects of rice straw on microflora in relation to nitrogen metabolism in submerged soil. Rice plants were cultured in submerged soil to which rice straw was applied. In the submerged soil applied with rice straw the value of Eh lowered. pH was higher in the upper layer than in the lower. The content of iron(II) in submerged soil increased, while that of ammonium nitrogen decreased when rice straw was applied and nitrate-nitrogen was hardly detected during the rice cultivation period Under application of rice straw the number of denitrifying bacteria observed to increase at the early growing stage of rice plant and to decrease thereafter, and that of nitrate reducing bacteria increased at the late growing stage. The number of ammonium oxidizing bacteria and that of nitrite oxidizing bacteria decreased continually but the latter were rather sharply decreased.

• Journal of the Mineralogical Society of Korea
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• v.24 no.2
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• pp.91-99
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• 2011

The turbidity in several wells of Samdong-myeon, Ulsan, exceeded potable groundwater standard (1 NTU). Mineralogical analysis showed that the fine suspended particles are ferrihydrite spheres with a size of less than $0.5\;{\mu}m$ and helical iron-oxidizing bacterial filaments, and their aggregates. Ferrihydrite was almost amorphous only showing two electron diffraction rings, and contained Si and P. Helical bacterial filaments were almost replaced by ferrihydrite. The helical bacteria have played an important role in the ferrihydrite formation by becoming the loci for ferrihydrite precipitation as well as oxidizing ferrous iron. The physicochemical conditions of low pH, low redox potential, high Ca concentration, and high alkalinity are consistent with the hydrogeochemical characteristics of carbonate groundwater, implicating that the inflow of deep ferriferous carbonate groundwater and its oxidation have caused the ferrihydrite turbidity in several wells of the study area.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.154-162
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• 1973

The rates and activation parameters for the halide $(Cl^{-}, Br^{-}, I^{-})$TeX> exchange reactions of substituted benzenesulfonyl-chloride, $XC_6H_4SO_2Cl$(X:p-MeO, H, p-Cl, p-Br, p-NO$_2l$) in dry acetone at two temperatures have been determined. It was found that the ion-pair of metal halide,$M^{+}X^{-}$, have negligible reactivity compared to free halide ions. It was also found that the nucleophilic order is $Cl^{-}>Br^{-}>I^{-}$for electron-donating substituent, and $Cl^{-}>I^{-}>Br^{-}$ for electron-withdrawing substituents. These results and convex nature of the Hammett plot are interpreted in the light of simple $S_N2$mechanism with the bond breaking becoming important for compounds with the electron withdra-wing substituents.

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.9-16
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• 2012

Standardized remediation process for the soil contaminated with arsenic is insufficient due to characteristics of its anion-mobility and speciation changed by Eh-pH of soil. One of the well-known efficient remediation processes is the modified soil washing that particle separation process by only water. However, it is required that the treatment plan for the fine soil what was discharged after modified soil washing. Therefore, this research suggests the treatment plan that the recycling method using arsenic immobilization by FeS-$H_2O_2$. The batch experiments results for the arsenic immobilization showed that the water content was at least 50%, the injection of FeS and $H_2O_2$ (assay-35%) were 8% (w/watdrybase) and 0.2 mL/10 g of fine soil respectively. Arsenic concentration with KSLT was decreased about 95.4%. The results indicated that the mixing of FeS-$H_2O_2$ was highly efficient on the immobilization of As-contaminated soil. The mixing ratio as 13% of bentonite with 3% of cement (at based on 100% of immobilized fine soil) was satisfied with standard of liner for landfill construction.

• Economic and Environmental Geology
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• v.32 no.5
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• pp.469-483
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• 1999

Two different types of deep groundwaters occur together in the Jungwon area: $CO_2$-rich water and alkali water. Each water shows distrinct hydrogeochemical and environmental isotopic characteristics. The $CO_2$-rich waters are characterized by lower pH(6.0~6.4), higher Eh (25~85mV) and higher TDS content (up to 3,300 mg/l), whereas the alkali type waters have higher pH (9.1~9.5), lower Eh (-136~-128mV) and lower TDS content (168~254 mg/l). The CO2-rich waters ($Pco_2$=up to 1atm) were probably evolved by the local supply of deep $CO_2$ during the deep circulation, resulting in enhanced dissolution of surrounding rocks to yield high concentrations of $Ca^{2+}, Na^+, Mg^{2+}, K^+\; and \;HCO_3\;^-$ under low pH conditions. On the other hand, the alkali type waters ($Pco_2$=about 10-4.6 atm) were evolved through lesser degrees of simple wate/rock (granite) interaction under the limited suppy of $CO_2$. The alkali waters are relatively enriched in F- (up to 14mg/l), whereas the F- concentration of$CO_2$-rich water is lower (2.2~4.8 mg/l) due to the buffering by precipitation of fluorite. The oxygen-hydrogen isotopes and tritium data indicate that compared to shaltion ($\delta$18O=-9.5~-7.8$\textperthousand$),two different types fo deep groudwaters (<1.0TU)were both derived from pre-thermonuclear (more than 40 years old) meteoric waters with lighter O-H isotopic composition ($\delta$18O=-9.5~-7.8$\textperthousand$) and have evolved through prolonged water/rock interaction. The $CO_2$-rich waters also show some degrees of isotopic re-equilibration with $CO_2$ gas. The $\delta^{34}S$ values of dissolved sulfates (+24.2~+27.6$\textperthousand$) in the $CO_2$-rich waters suggest the reduction of sulfate by organic activity at depths. The carbon isotope data show that dissolved carbon in the $CO_2$-rich waters were possibly derived either from dissolution of calcite or from deep $CO_2$ gas. However, strontium isotope data indicate Ca in the $CO_2$-rich waters were derived mainly from plagioclase in granite, not from hydrothermal calcites.