• Progress in Superconductivity
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• v.7 no.1
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• pp.92-96
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• 2005

YBCO thin films on metal substrates were prepared by the metal-organic deposition using trifluoroacetates (TFA-MOD). To compensate the loss of Ba element from the precursor films due to the reaction with $CeO_2$ cap layer, we have employed Ba-excessive precursor solutions of $YBa_{2+x}Cu_{3}O_{7-{\delta}}$ ($0{\le}x{\le}0.1$). The precursor solutions were dip-coated on the metal substrates with $CeO_2$ cap layer, initially heated up to $400^{\circ}C$, and finally fired at the various high temperatures for 2 h in a reduced oxygen atmosphere. With this approach, YBCO films possessing critical temperature over 85 K could be successfully prepared on the metal substrates. The highest $T_{c,zero}$ value of 86 K was obtained from the Ba-excessive YBCO film of x=0.005 in $YBa_{2+x}Cu_{3}O_{7-{\delta}}$ fired at $750^{\circ}C$ for 2 h. However, unexpected $T_c$ suppression even in Ba-excessive YBCO samples requires further identification.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.154-162
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• 2000

A technique to suppress the low frequency ripple voltage of the DC output ${\gamma}$oltage in three-phase buck d diode rectifiers is presented in this paper. The proposed pulse frequency modulation method is employed to r regulate the output voltage of the buck diode rectifiers and guarantee zero-current switching of the switch over the Vvide load range. The pulse frequency control method used in tIns paper shows generally good p performance such as low THD of the input line current and unity power factor. In addition, the pulse f freιluency method can be effectively used to suppress the low frequency voltage ripple appeared in the dc output voltage. The proposed technique illustrates its validity and effectiveness through the respective s simulations and experiments.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.71-79
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• 2004

Toxicities of 42 pesticides (13 acaricides, 13 insecticides, 13 fungicides and 3 adjuvants) commonly used to control rose insect, mite, and disease pests were evaluated to the two-spotted spider mite, Tetranychus urticae egg and adult, and its predator Phytoseiulus persimilis egg, nymph and adult at the recommended concentration. The effect of density suppression of T urticae by predatory mite and pesticide mixture on the rose in the greenhouses was also investigated. Among 13 acaricides tested, acequinocyl, bifenazate, fenbutatin oxide and spirodiclofen showed much less toxicity to P. persimilis than to T urticae. Among insecticides, acetamiprid, imidacloprid, spinosad, thiamethoxam and acetamiprid＋etofenprox showed low toxicity to P. persimilis. and T ruticae. Among 13 fungicides, azoxystrobin, kresoxim-methyl, myclobutanil, nuarimol, triadimefon, triflumizole and oxadixyl＋mancozeb had a negligible effect on P. persimilis and T. urticae. Among three adjuvants, cover and siloxane expressed high toxicity, while spreader showed very low toxicity to P. Persimilis. In the greenhouses experiments, the density of T urticae before treatment was 65.3 mites per leaf. However, their density after release about 30 predatory mites per rose abruptly decreased from 3.8 mites at 11th day to zero mite at 20th day. During survey periods, four treatments of fungicides (kresoxim-methyl, myclobutanil, nuarimol, triflumizole) for the control of Sphaerotheca pannosa and one treatment of insecticide (spinosad) the control of Frankliniella occidentalis were applied, and these treatments had no the pesticides had no effect on the predatory mite density. It may be suggested from these results that four acaricides, five insecticides, seven fungicides, and one adjuvant could be incorporated into the integrated T. urticae management system with P. persimilis on rose cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.65-75
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• 2019

The government is promoting recycling of waste resources through the enactment of Fundamental Law on Resource Circulation, the revision of the Wastes Control Act and zero-landfilling of untreated waste through improved processes such as recycling and diversification. As of 2015, the total amount of landfilled waste is 38,308 ton/day in Korea. The amount of landfilled waste from industrial sectors is 23,577 ton/day, accounting for 62 % of total landfilled waste. In the study, we investigated the characteristics of the thermal treatment residue among inorganic wastes and estimated the landfill reduction potential according to the relevant recycling criteria, which can go through recycling paths. As a result, it is estimated that about 5~42 % of the landfilled waste can be reduced in case mandatory recycling and landfill suppression policies such as recycling criteria for thermal processing residues and expansion of recycling obligation targets should be implemented. In order to minimize landfill disposal, it is necessary to expand the diversity of waste recycling type and the usage of recycled products.