• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.463-465
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• 2003

전기분해에 의한 부상현상을 이용하여 유류로 오염된 토양 세정 후 발생되는 유출수 중 유분 등을 분리하기 위한 적정 운전조건을 찾고자 하였다. 전기분해 반응조(200 $\times$ 10 $\times$15cm)에 혼합 계면활성제 (POE5 : POE14, 1:1) 1% 용액에 디젤을 1,000mg/L 농도로 용해시켜 실험하였다. 양극에는 티나늄 코팅전극, 음극으로는 스테인레스 스틸전극을 이용하였다. 반응시간은 62분( 반응: 60분, 부상시간: 2분) 이었으며 전압은 6V였다. 전해질 첨가에 의한 영향을 알아보기 위하여 실험한 결과, 전해질을 첨가하였을 경우 첨가하지 않았을 때보다 40% 정도의 효율이 증가하였다. 적정 전해질, 주입농도 및 반응시간을 알아보기 위하여 1N NaCl과 NaOH의 농도를 변화시켜 가면서 실험하였다. NaCl의 경우 더 좋은 효율을 나타내었다. 전해질의 농도는 0.2 - 1.0% 의 농도 범위에서 NaCl와 NaOH 모두 농도에 따라 순차적으로 효율이 증가하였다. 두 전해질 모두 0.4 - 1.0% 농도 범위에서 평형에 도달하는 시간은 20분으로 나타났다.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.9-16
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• 2003

A new method has been proposed and developed that solves the problem of decreasing electroosmotic flow rate by excess $H^{+}$ and precipitation of heavy metal by $OH^{-}$. An electrolytic solution was circulated between the anode and cathode compartments that enabled the pH at the anode and cathode to be controlled. The change of the soil pH by circulation systems affects the operation time, by lowering the rate of increase of the electric potential gradient, and the removal efficiency of heavy metals, by affecting the soil pH. Since there was no effluent from the cathode compartment in circulation system, there was no need to treat the wastewater after the experiment, which resulted in the reduction of influent electrolyte volume.

• 전기의세계
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• v.12
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• pp.12-23
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• 1963

전력연구소 전식연구실에서는 상기 지구의 전식작용이 예상되는 10여개점에서 예비조사를 한 결과 상수도관이 전식작용을 받고 있음을 확인하고, 순화동지구의 상수도관의 전식작용 실태조사에 착수하게 되었다. 지중 매설금속체의 부식에는 누설전류에 의한것 외에도 전기화학작용에 의한것 화학반응에 의한것, 물리적 작용에 상반되는것 등이 있다. 누설전류에 의한 것은, 실제의 경우, 전철이 궤조로 부터의 누설전류는 전해질로서 볼 수 있는 토야을 매체로 하여, 이것보다 저항이 적은 매설금속체에 유입하여, 변전소 근처에서 이것으로부터 유출 귀류한다.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.56-60
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• 2003

The optimal operation conditions of electrofloatation for oil-water separation of soil flushing effluent including electrolyte and pH were investigated. The reactor (200 ${\times}$ 10 ${\times}$ 15 cm) for the experiment was constructed by using acrylic plate. Diesel concentration was 1,000 mg/L in the 1 % mixed surfactant solution ($POE_5$: $POE_{14}$ 1: 1). Titanium coated electrode was used as cathode and stainless steel electrode as anode. Reaction time was 62 minutes (reaction time: 60 min., flotation time: 2 min.) and voltage was 6 V. The separation efficiency of electrofloatation was improved to 40% by electrolyte addition. Furthermore, NaCl (1N) added as electrolyte was showed enhanced efficiency compared to NaOH (1N). While, the effect of both NaCl and NaOH was sequentially increased in the range of 0.2∼1.0% (0.02∼0.1 M). The equilibrium time was found as 20 min. in the range of 0.4∼1.0% (0.04∼0.1M) for both of them.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.7-13
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• 2006

The effects of electrolytes were investigated on the removal efficiency when several different electrolytes were used to change the electrode reaction in an electrokinetic (EK)-Fenton process to remediate phenanthrene-contaminated soil. Electrical potential gradient decreased initially due to the ion entrance into soil and then increased due to the ion extraction from soil under the electric field. Accumulated electroosmotic flow was $NaCl>KH_2PO_4>MgSO_4$ at the same concentration because the ionic strength of $MgSO_4$ was the highest and $Mg(OH)_2$ formed near the cathode reservoir plugged up soil pore to inhibit water flow. When hydrogen peroxide was contained in electrolyte solution, removal efficiency increased by Fenton reaction. When NaCl was used as an electrolyte compound, chlorine ($Cl_2$) was generated at the anode and dissolved to form hypochlorous acid (HClO), which increased phenanthrene removal. Therefore, the electrode reaction of electrolyte in the anode reservoir as well as its transport into soil should be considered to improve removal efficiency of EK-Fenton process.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.17-21
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• 2011

Korean bennudagrass collections showed diverse genetic variations in their morphology, growth habit, and cytological aspects. Chromosome number and nuclear DNA content of the bennudagrasses indicated a ploidy level ranging from triploid (2n=3x) to hexaploid (2n=6x). In this study, we investigated the different responses of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase) and cell membrane stability of those bennudagrass cytotypes to lower temperature and shorter day length, which meets a dormant induction in Korea. All the antioxidant enzymes were found to be higher during dormant stage, while the heme-containing catalase which converts hydrogen peroxide ($H_2O_2$) to water and oxygen molecules was activated before dormant initiation in the three cytotypes except for hexaploid bennudagrass. The triploid and tetraploid which exhibited relatively finer leaves and a rapid establishment speed were found to show increased activities of superoxide dismutase and peroxidase enzyme. The malondialdehyde(MDA) which is a product of lipid peroxidation in the cell membrane damaged by the hydroxyl radical was increased in all cytotypes as temperature declined, and tri- and tetraploids which had more protective antioxidant enzymes demonstrated a significantly lower MDA production. Similarly electrolyte leakage was higher in penta- and hexaploidy, seemingly more damage to cell membrane when low temperature was implemented. Results indicated that antioxidant responses of different cytotypes were genetically specific, which needs to be investigated the relevance with the low temperature tolerance in the bermudagrass further at the molecular level.

• Journal of the Korean Electrochemical Society
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• v.18 no.3
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• pp.121-129
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• 2015

The platinum anode for the electrolytic reduction process is generally surrounded by a nonporous ceramic shroud with an open bottom to offer a path for $O_2$ gas produced on the anode surface and prevent the corrosion of the electrolytic reducer. However, the $O^{2-}$ ions generated from the cathode are transported only in a limited fashion through the open bottom of the anode shroud because the nonporous shroud hinders the transport of the $O^{2-}$ ions to the anode surface, which leads to a decrease in the current density and an increase in the operation time of the process. In the present study, we demonstrate the electrolytic reduction of 1 kg-uranium oxide ($UO_2$) using the porous shroud to investigate its long-term stability. The $UO_2$ with the size of 1~4mm and the density of $10.30{\sim}10.41g/cm^3$ was used for the cathode. The platinum and 5-layer STS mesh were used for the anode and its shroud, respectively. After the termination of the electrolytic reduction run in 1.5 wt.% $Li_2O-LiCl$ molten salt, it was revealed that the U metal was successfully converted from the $UO_2$ and the anode and its shroud were used without any significant damage.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.189-195
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• 2023

As a PEMFC (Polymer Exchange Membrane Fuel Cell) cathode catalyst, Pt-Co/C has recently been widely used because of its improved durability. In a fuel cell, electrodes and electrolytes have a close influence on each other in terms of performance and durability. The effect on the electrochemical durability of the electrolyte membrane when Pt-Co/C was replaced in the Pt/C electrode catalyst was studied. The durability of Pt-Co/C MEA (Membrane Electrode Assembly) was higher than that of Pt/C MEA in the electrochemical accelerated degradation process of PEMFC membrane. As a result of analyzing the FER (Fluorine Emission Rate) and hydrogen permeability, it was shown that the degradation rate of the membrane of Pt-Co/C MEA was lower than that of Pt/C MEA. In the OCV (Open Circuit Voltage) holding process, the rate of decrease of the active area of the Pt-Co/C electrode was lower than that of the Pt/C electrode, and the amount of Pt deposited on the membrane was smaller in Pt-Co/C MEA than in Pt/C MEA. Pt inside the polymer membrane deteriorates the membrane by generating radicals, so the degradation rate of the membrane of Pt/C MEA with a high Pt deposition rate was higher than Pt-Co/C MEA. When the Pt-Co/C catalyst was used, the electrode durability was improved, and the amount of Pt deposited on the membrane was also reduced, thereby improving the electrochemical durability of the membrane.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.171-178
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• 1987

Pathogenic isolates of Alternaria mali produced host-specific toxin(AM-toxin) in liquid culture. The toxin was also released by germinating spores of the fungus. The physiological event of apple leaves induced by germinating spores was an increased loss of electrolytes from susceptible leaves. This reaction was evident soon after spore inoculation, indicating that the leakage was caused by AM-toxin from germinating spores. Typical symptoms were developed only in susceptible leaves of apple within 48hr after inoculation with pathogenic spores. Similar symptoms occurred on susceptible leaves when non-pathogenic isolates plus AM-toxin were used.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.329-336
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• 2014

As an abiotic stress, chilling stress is one of the major factors limiting plant growth and increasing susceptibility to pathogens. Therefore, enhancing stress tolerance in plants is an important strategy for their survival under unfavorable environmental conditions. The objective of this study was to determine the effects of the exogenous application of salicylic acid (SA) or nitric oxide (NO) on chilling tolerance in pepper seedlings. Pepper (Capsicum annuum L. 'kidaemanbal') seedlings were grown under normal growing conditions ($20/25^{\circ}C$, 15 hours photoperiod, $145{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, fluorescence lamps) for 23 days after transplanting. The solution (3 mL) of 1 mM SA and 0.3 mM NO with surfactant triton 0.1% were sprayed two times a week, respectively. Right after the completion of chemical application, seedlings were subjected to chilling condition at $4^{\circ}C$ for 6 hours under dark condition and then the seedlings were recovered at the normal growing conditions for 2 days. In order to assess plant tolerance against chilling stress, growth characteristics, chlorophyll fluorescence (Fv/Fm), and membrane permeability were determined after chilling stress imposition. Total phenolic concentration and antioxidant capacity were measured during the whole experimental period. Disease incidence for pepper bacterial spot and wilt was also analyzed. Pepper seedlings treated with SA or NO were maintained similar dry mass ratio, while the value in control increased caused by chilling stress suggesting relatively more water loss in control plants. Electrolyte leakage of pepper seedlings treated with SA or NO was lower than that of control 2 days after chilling treatment. Fv/Fm rapidly decreased after chilling stress in control while the value of SA or NO was maintained about 0.8. SA increased higher total phenolic concentration and antioxidant capacity than NO and control during chemical treatment. In addition, increase in total phenolic concentration was observed after chilling stress in control and NO treatment. SA had an effect on the reduction of bacterial wilt in pepper seedlings. The results from this study revealed that pre-treatment with SA or NO using foliar spray was effective in chilling tolerance and the reduction of disease incidence in pepper seedlings.