• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.725-732
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• 1999

It is usual to use hydrophilic-coated aluminum foil for evaporator fin of air-conditioners to reduce air flow resistance caused by the water droplets condensed on the fin surface. The major effect of a hydrophilic coating is to reduce the contact angle of the condensate and prevent bridging of the condensate between the adjacent fins. The performance of hydrophilic coating generally tends to be degraded as it is used since the coating material is washed down by the condensate. In the present work, several types of hydrophilic coatings were evaluated in terms of durability of hydrophilicity, corrosion resistance and heat resistance. Results showed that an improved hydrophilic coating of resin type presented superb qualify in terms of durability and corrosion resistance while having almost the same level of qualify in heat resistance compared with the others.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.626-639
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• 2015

Ice resistance is defined as the time average of all longitudinal forces due to ice acting on the ship. Estimation of ship's resistance in ice-covered waters is very important to both designers and shipbuilders since it is closely related to propulsion of a ship and it determines the engine power of the ship. Good ice performance requires ice resistance should be as low as possible to allow different manoeuvres. In this paper, different numerical methods are presented to calculate ice resistance, including semi-analytical method and empirical methods. A model test of an icebreaking vessel that was done in an ice basin has been introduced for going straight ahead in level ice at low speed. Then the comparison between model test results and numerical results are made. Some discussions and suggestions are presented as well to provide an insight into icebreaking vessel design at early stage.

• Korean Journal of Materials Research
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• v.25 no.9
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• pp.429-434
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• 2015

Resistance switching memory cells were fabricated using atomically dispersed Pt-$SiO_2$ thin film prepared via RF co-sputtering. The memory cell can switch between a low-resistance-state and a high-resistance-state reversibly and reproducibly through applying alternate voltage polarities. Percolated conducting paths are the origin of the low-resistance-state, while trapping electrons in the negative U-center in the Pt-$SiO_2$ interface cause the high-resistance-state. Intermediate resistance-states are obtained through controlling the compliance current, which can be applied to multi-level operation for high memory density. It is found that the resistance value is related to the capacitance of the memory cell: a 265-fold increase in resistance induces a 2.68-fold increase in capacitance. The exponential growth model of the conducting paths can explain the quantitative relationship of resistance-capacitance. The model states that the conducting path generated in the early stage requires a larger area than that generated in the last stage, which results in a larger decrease in the capacitance.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.194-200
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• 1990

The diamondback moth (Plutella xylostella L.) was selected over 24 generations with fenvalerate. The resulting resistant strain was tested to study development of insecticide resistance and cross resistance to some insecticides in the laboratory. Insecticide resistance of diamondback moth at the 24th generation devleoped 66.2 fold compared to the parent strain for fenvalerate. The fenvalerate selected strain exhibited 145 fold, a high level of cross resistance to deltamethrin, and also showed 17.4-45.0 fold cross resistance to alphamethrin, cypermethrin, fenvalerate, permethrin, and tetramethrin in the pyrethroid insecticides. The fenvalerate selected strain showed 2.5-4.3 fold, low cross resistance to diazinon, dichlorvos, EPN, BPMC, cabaryl, and methomyl. However, it did not show cross resistance to acephate, fenitrothion, phenthoate, and carbofuran.

• Plant Resources
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• v.8 no.1
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• pp.32-35
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• 2005

This study was conducted to investigate the influence of $K_{2}O$ fertilizer application on growth, yield and lodging resistance of rice. Culm length and panicle length were lowest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ plot but number of panicle, percentage of fruitful culm, $1{\ell}$ grain weights of paddy rice and brown rice, 1,000 grains weight of brown rice, brown rice ratio, yields of paddy rice and brown rice were highest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a plot. Bending moment, breaking strength and lodging index were lowest at the treatment of fertilizer level, $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a plot. Judging from the results reported above, an optimum fertilizer level of rice for lodging resistance is most likely be $N-P_{2}O_{5}-K_{2}O=16-8-8$ kg/10a treatment.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.1117-1128
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• 2021

The purpose of the current study was to investigate the effects of 4-week health promotion intervention program consisting of high-intensity aerobic exercise to improve energy consumption and cardiorespiratory capacity, circuit training to strengthen muscular strength and endurance and education for lifestyle changes on the obesity level, physical fitness, insulin resistance and metabolic syndrome among overweight or obese elementary school students. Twenty three overweight or obese children as obese group and 15 normal body weight children as normal group were recruited. The health promotion program consisted of two exercise sessions and one education session, 3days/week in 4-week. Obesity level(body mass index, waist circumference, %body fat), physical fitness(muscular strength, muscular endurance, flexibility, cardiopulmonary fitness), insulin resistance(homeostasis model assessment of insulin resistance) and metabolic syndrome risk factors(blood pressure, fasting glucose, triglycerides, high density lipoprotein cholesterol) were measured. There was not significant decrease in obesity level; however, there were significant improvement in physical fitness, insulin resistance and metabolic syndrome risk factors after program participation among obese children. As a result, through participation in the summer camp consisting mainly of exercise, the improvement of the physical fitness level and the decrease of insulin resistance had an effect on the reduction of the metabolic syndrome frequency.

• Korean journal of applied entomology
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• v.28 no.4
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• pp.237-243
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• 1989

These studies were conducted to investigate the development of chemical resistance in two-spotted spider mite (Tetranychus urticae Koch) through alternate selection for a given period of time with four acaricides including ethion of organophophours compound, dicofol of organo-chlorine compound, cyhexatin of organo-tin compound, and biphenthrin of synthetic pyrethroid compound; and to examine multiple-resistance among the acaricides to the selected populations. The development levels of chemical resistance in the two-spotted spider mite were greatly varied under alternate selection with the different chemical-group combination of four acaricides. Resistant levels of the ethion/dicofol-selected population at 13th-13th generation showed 49.4-fold resistance to ethion and 18.1-fold to dicofol; the ethion/cyhexatin-selected population at 9th-9th generation exhibited 28.1-fold to ethion and 5-fold to cyhexatin; the ethion/biphenthrin-selectd population at 10th-10th generation revealed 39.8-fold to ethion and 19.2-fold to biphenthrin. However, the dicofol/cyhexatin-selected population at 9th-9th generation showed 11.3-fold to dicofol and 4.9-fold to cyhexatin, and the dicofol/biphenthrin-selected population at 12th-12th generation exhibited 11.2-fold to dicofol and 9.4- fold to biphenthrin, while the cyhexatin/biphenthrin-selected population at 9th-9th generation revealed 3.7-fold to cyhexatin and 7.7-fold to biphenthrin. In case of alternate selection, the ehtion/dicofol-selected population revealed moderate multiple-resistance level to biphenthrin. The ethion/cyhexatin-selected and the ethion/biphenthrin-selected populations showed low mutiple-resistance level to biphenthrin and dicofol, respectively. However, the dicofol/cyhexatin-selected, the dicofol/biphenthrin-selected and the cyhexatin/biphenthrin-selected populations exhibited high multiple-resistance level to ethion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.297-306
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• 2017

The concrete median barrier used currently in South Korea was developed the impact level of SB5-B(270kJ). However, the impact level of SB6(420kJ) should be considered in many placed with the increased accident of heavy vehicles. In order to increase the impact resistance of newly developed concrete median barrier, the computer simulation was conducted before real field test. For the accurate behavior of concrete, the parameter, such as impact vehicle, concrete cover depth and deterioration, was important. In this paper, a parametric study was conducted depending on vehicle curb weight, concrete cover depth and level of deterioration. The impact resistance of concrete median barrier was severely changed depending on vehicle curb weight and concrete cover depth. Furthermore, the impact resistance of concrete median barrier was also decreased due to deterioration of concrete, therefore the repair and rehabilitation should be conducted for damaged concrete depending on deterioration level. Therefore, vehicle curb weight, cover depth of concrete structures and deterioration level of concrete should be carefully considered for conducting analysis of concrete structure to vehicle collision.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.6
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• pp.1-11
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• 1996

The rotor flux level need be changed frequently for field weakening or power efficiency control. Motor inductances depend on rotor flux but not on machine temperature. On the other hand, rotor resistance varies greatly with the machine temperature. Motor parameters such a sinductances and rotor resistance should be known precisely in order to attain high dynamic performance of inductin motor. In this paper, efficient an dnovel identification algorithms for motor inductances and rotor resistance are presented. The rotor flux is changed. As the result, the slip frequency is varied. The identificatin algorithm for rotor resistance measures the varied slip frequency and alters the estimated rotor resistance. Then, the estimated value of rotor resistance will approach its real value. The proposed identification algorithms are computationally simple and have very small identification errors.

• Natural Product Sciences
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• v.6 no.1
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• pp.36-39
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• 2000

Acorenone, a diterpene isolated from Acorus gramineus, showed strong resistance inhibitory activity against multi-drug resistant microorganisms such as Staphylococcus aureus SA2, which has resistance to 10 usual antibiotics including chloramphenicol (Cm). At the level of $5\;{\mu}g/ml$ when combined with $50\;{\mu}g/ml$ of Cm. Bacterial resistance to Cm is due to the presence in resistant bacteria of an enzyme, chloramphenicol acetyltransferase (CAT), which catalyses the acetyl-CoA dependent acetylation of the antibiotic at C-3 hydroxyl group. To elucidate the mechanism of resistant inhibitory effect, the acorenone which had the strongest resistant inhibitory activity, was investigated on the CAT assay. As the result, the combination of Cm and acorenone showed the strongest inhibitory activity on CAT as noncompetitive and dose dependent manner.