• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.123-133
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• 2023

Wastewater generated in the secondary battery production process contains lithium and high-concentration sulfate. Recently, as demand as demand for high-Ni precursors with high-energy density has surged, nickel emission is also a concern. Lithium and sulfate are not included in the current water pollutant discharge standard, so if they are not properly processed and discharged, the negative effect on future environment may be great. Therefore, in this study, the ecotoxicity of lithium, nickel, and sulfate, which are potential contaminants that can be discharged from the secondary battery production process, was evaluated using water flea (Daphnia magna) and luminescent bacteria (Aliivibrio fischeri). As a result of the ecotoxicity test, 24-hour and 48-hour D. magna EC₅₀ values of lithium were 18.2mg/L and 14.5mg/L, nickel EC50 values were 7.2mg/L and 5.4mg/L, and sulfate EC₅₀ values were 4,605.5mg/L and 4,345.0mg/L, respectively. In the case of D. magna, it was found that there was a difference in ecotoxicity according to the contaminants and exposure time (24 hours, 48 hours). Comparing the EC₅₀ of D. magna for lithium, nickel, and sulfate, the EC₅₀ of nickel at 24h and 48h was 39.6-37.2% compared to lithium and 0.1-0.2% compared to sulfate, which was the most toxic among the three substances. The difference appeared to be at a similarlevelregardless of the exposure time. The EC₅₀ of sulfate was 253.0-299.7% and 639.5-804.6%, respectively, compared to lithium and nickel, showing the least toxicity among the three substances. The 30-minute EC₅₀ values of luminescent bacteria forlithium, nickel, and sulfate were 2,755.8mg/L, 7.4mg/L, and 66,047.3mg/L,respectively. Unlike nickel, it was confirmed that there was a difference in sensitivity between D. magna and A. fischeri bacteria to lithium and sulfate. Studies on the mixture toxicity of these substances are needed.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.456-462
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• 2010

Baseline sensitivity to benthiavalicarb, iprovalicarb and dimethomorph included into carboxylic acid amide (CAA) group was evaluated in 180 isolates of Phytophthora capsici over 4 years from 2005 to 2008. $EC_{50}$ (effective concentration inhibiting mycelial growth by 50%) value of benthiavalicarb ranged from $0.015{\mu}g\;mL^{-1}$ to $0.049{\mu}g\;mL^{-1}$ with a mean of $0.033{\mu}g\;mL^{-1}$. The mean values of $EC_{50}$ of iprovalicarb and dimethomorph were 0.411 (0.197 - 0.556) ${\mu}g\;mL^{-1}$ and 0.271 (0.101 - 0.798) ${\mu}g\;mL^{-1}$, respectively. Although there was no increasing tendency in $EC_{50}$of benthiavalicarb and iprovalicarb during 4 years, $EC_{50}$ of dimethomorph was increased gradually by laps of time. There was no cross-resistance between each fungicide used in this study and metalaxyl. Among fungicides included into CAA group, there was a positive correlation between benthiavalicarb and iprovalicarb, and between dimethomorp and mandipropamid.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.918-923
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• 2008

We proposed an embedded capacitor with the unique electrode structure, which electrodes are located on the same plane and dielectric gap was formed by electrodes. We named it 'Gap type EC', and it was analyzed by the FEM(Finite element Method) program tool. The resonant frequency of Cap type EC was obtained at more higher frequency region. Also, resonant frequency was changed with the magnitude and thickness of electrodes. The Gap type EC with the dielectric gap of $50{\mu}m$ showed capacitance density of $55pF/cm^2$. This value is the higher than that of conventional EC. So, we concluded that the Gap type EC can be a good candidate for high frequency decoupling.

• Kyungpook Mathematical Journal
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• v.50 no.1
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• pp.101-107
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• 2010

A module M is said to satisfy the $EC_{11}$ condition if every ec-submodule of M has a complement which is a direct summand. We show that for a multiplication module over a commutative ring the $EC_{11}$ and P-extending conditions are equivalent. It is shown that the $EC_{11}$ property is not inherited by direct summands. Moreover, we prove that if M is an $EC_{11}$-module where SocM is an ec-submodule, then it is a direct sum of a module with essential socle and a module with zero socle. An example is given to show that the reverse of the last result does not hold.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.260-266
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• 2015

To examine the changes in resistance to benomyl of Fusarium species causing bakanae disease, Fusarium isolates were collected in Korea, and pathogenicity tests were performed using rice seeds in vitro. Minimum inhibitory concentration (MIC) and effective concentration of 50% ($EC_{50}$) values of isolates were examined using the agar dilution method. High frequency distribution of MIC values to benomyl against isolates collected in 2006~2007 and 2013~2014 years were $1.5625{\sim}3.125{\mu}g/mL$ and more than $25{\mu}g/mL$, respectively. The mean $EC_{50}$ value of isolates to benomyl increased from $1.6397{\mu}g/mL$ in 2006~2007 to $2.4892{\mu}g/mL$ in 2013~2014. Based on MIC and $EC_{50}$ values of isolates, the moderate resistance of benomyl were determined as more than $25{\mu}g/mL$ of MIC and less $2.4{\mu}g/mL$ of $EC_{50}$ value, and resistant isolates to benomyl were determined as more than $2.4{\mu}g/mL$ of $EC_{50}$ value. Compared with the ratio of resistant isolates in 2006~2007, the ratio of resistance isolates in 2013~2014 increased from 12.5% to 36.4%. In addition, multiple resistant isolates to prochloraz as well as benomyl increased to 20.3% in 2013~2014.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.83-90
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• 2004

A pot experiment was conducted to find out the effects of nitrogen content of irrigation water and soil EC on lettuce growth under plastic film house conditions. The square-pots with 42 x 54.5 x 22 cm in length, width and height, were filled with two different soils of different EC. Lettuce was grown with different nitrogen fertilizer application levels including non fertilization (Non-F), decrement of 50% of nitrogen fertilizer recommended by soil testing (DNFRST-50) and fertilization recommended by soil testing (FRST). Two kinds of irrigation water of different nitrogen contents, $6.6mg\;L^{-1}$ and $21.0mg\;L^{-1}$, were used for the experiment. In the low EC soil irrigated with low nitrogen water, fresh weights of lettuce were 6,733, 11,933 and $12,733kg\;ha^{-1}$ for the treatments of Non-F, DNFRST-50 and FRST, respectively. While with high nitrogen water, the yields were 9,733, 13,400 and $12,800kg\;ha^{-1}$, respectively. In the high EC soil irrigated with low nitrogen water, lettuce yields of the Non-F, DNFRST-50 and FRST treatments were 12,400, 12,867 and $10,400kg\;ha^{-1}$, respectively, and with high nitrogen irrigated water lettuce yields of the Non-F, DNFRST-50 and FRST treatments were 13,600, 14,067 and $10,733kg\;ha^{-1}$, respectively. Nitrogen uptake of lettuce from ferilizer in DNFRST-50 was higher than of FRST. Nitrogen uptake of lettuce from irrgation water was found in soils of low EC, but it was not found in soils of high EC. These results suggest that both soil EC and nitrogen content of irrigation water should be considered when we recommend the level of fertilizer application for lettuce.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.111-116
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• 1979

The experiments were carried out to evaluate the effectiveness of some insecticides in the control of the pine gall midges (Thecodiplosis japonensis Uchida et Inouye) when the low-volume of the insecticides were applied by the mist foliar sprayer. The insecticides, Salithion $(24\%\;Ec)$, Omethoate $(Folimat^{(R)}\;50\%\;Ec)$, Monocrotopos $(Azodrin^{(R)}24\%\;Ec)$, Acephate $(Ortran^{(R)}\;50\%\;Wp)$, Metalkamate $(Bux^{(R)}24\%\;Ec)$. BPMC $(Bassae^{(R)}50\%\;Ec)$ and MIPC $(Mipcin\;50\%\;Wp)$ were tested with 100, 200 and 400 times of water solution on the basis of single application at the six different intervals. Salithion was the most effective for the pressure of the gall formation by the pine gall midges and Omethoate, Monocrotophos and Metalkamate were relativey effective and others no effective. The most reliable concentration of the insecticides was 100 times of water solution, and the feasible timing of insecticide application on the basis of single application would be from May 9 to July 1 with Salithion, June 6 with Metalkamate and June 20 with Omethoate and Monocrotophos. The number of pine needles with the larval injured signs (no larvae in the needles) excluded the gall-formed needles were relatively higher in the treatments of Omethoate, Salithion and Monocrotophos than other insecticides. The treatments of Omethoate, Salithion and Monocrotophos caused the lower larval population in the gall than other insecticides.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.272-278
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• 2015

Colletotrichum gloeosporioides is one of the most serious pathogens of persimmon in Korea. In 2013, 67 isolates of C. gloeosporioides were isolated from infected fruits, leaf and twigs of persimmon (Diosprosi kaki) at Sangju, Gyeongsangbukdo and fungal responses against five fungicides (prochloraz manganese complex, tebuconazole, mancozeb+myclobutanil, fluquinconazole+prochloraz, and tebuconazole+tolyfluanid) were evaluated by their growth on the fungicide-medium. All isolates were inhibited mycelium growth on the medium with each recommended application concentration of flied. $EC_{50}$ (${\mu}g/ml$) of tebuconazole was from 0.02 to 1.04 and average was 0.31. $EC_{50}$ (${\mu}g/ml$) of prochloraz manganese complex was 0.02~0.23 average was 0.078. Average $EC_{50}$ values (${\mu}g/ml$) of Fluquinconazole+Prochloraz (FP) was 0.029. On the basis $EC_{50}$ (${\mu}g/ml$), the correlation coefficient (r) between tebuconazole and prochloraz manganese complex, prochloraz manganese complex and FP, tebuconazole and FP were 0.42, 0.44 and 0.27, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.828-834
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• 2012

The ecotoxicity detection device for preliminary test (Test jig) was manufactured to develop the biological early warning system using Vibrio fischeri. In this study, the ecotoxicity detection charateristics of the Test jig was investigated for 6 heavy metals (Cr, Zn, Pb, Cd, Cu and Hg). It was observed that relative luminescence unit (RLU) of Vibrio fischeri constantly decreased by the concentrations of the tested heavy metals. In contrast with other heavy metals, RLUs of Pb and Hg constantly decreased even at low concentrations. RLU of Hg drastically decreased when its concentration increased from 0.13 mg/L to 0.25 mg/L. $EC_{50}$ values of Cr, Zn, Pb and Cd gradually decreased with exposure time, whereas there was no significant change in $EC_{50}$ values of Cu and Hg with time. On the other hand, $EC_{50}$ values between the Test jig and Reference device were compared to evaluate the ecotoxicity detection performance of the Test jig. No big difference was found in $EC_{50}$ vlaues between the two devices, indicating that the Test jig could be applied as the ecotoxicity detection device for heavy metals.

• Research in Plant Disease
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• v.30 no.2
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• pp.131-138
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• 2024

The effects of five fungicides on the spore growth phase of Alternaria dauci, which causes carrot leaf blight, were tested using the spore viability assay (SVA) and agar dilution method (ADM). The average EC₅₀ values for chlorothalonil against seven isolates of A. dauci examined by SVA and ADM were 14.21 ㎍/ml and more than 100 ㎍/ml. Dithianon and folpet also had lower EC₅₀ values in SVA than in ADM, while iminoctadine trisalbesilate had lower EC₅₀ value in ADM. For fluazinam, the EC₅₀ values of SVA and ADM were 1.63 and 2.40 ㎍/ml, respectively. As EC₅₀ values of five fungicides according to the spore growth phase of A. dauci KACC 42997, the efficacy of each fungicide as chlorothalonil, dithianon, and folpet decreased when treated after spore germination rather than when treated with spores before germination. However, iminoctadine tris-albesilate was more effective when treated after spores germinated than when treated before treatment. The excellent effect of fluazinam on the pathogen was maintained until A. dauci KACC 42997 was cultured in potato dextrose broth for 6 hr and the germ tube grew beyond the size of the spore. However, when treated with iminoctadine tris-albesilate and fluazinam after culturing for 12 hr, as the EC₅₀ values of the two fungicides increased to 8.87 and 20.65 ㎍/ml, their efficacies decreased. The results of this study show that the treatment time of the fungicide should be determined by considering the effect of the fungicide on the spore growth phase of pathogens.