• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1077-1083
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• 1999

This study was aimed to evaluate the effectiveness of hydrophilic, lipophilic antioxidants and emulsifiers by HLB (hydrophilic lipophilic balance) in different oil systems. Lipophilic antioxidant (${\delta}-tocopherol$), hydrophilic antioxidant (gallic acid) and emulsifier(lecithin, tween 20, span 60) were evaluated in relation to oil stability in bulk oil system (soybean oil) and emulsified with Tween 80 at $60^{\circ}C$. In the storage test ($60^{\circ}C$), gallic acid was more effective on the stability of oil oxidation than ${\delta}-tocopherol$ in bulk and emulsion system. Lecithin as a hydrophilic emulsifier was more effective than tween 20 on the stability of oil oxidation in bulk and emulsion system. Also span 60, a lipophilic emulsifier, was more effective than tween 20, a hydrophilic emulsifier, in bulk and emulsion systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.971-980
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• 2013

System performance improvement through the concentrated residual dispersion per span (RDPS) in special transmission fiber spans in optical transmission links with dispersion management (DM) for wavelength division multiplexed (WDM) transmission is investigated through the comparison with the performance in optical transmission links with uniform RDPS in every fiber spans. It is confirmed that, in optical links with RDPS of 0 ps/nm uniformly distributed in the rest fiber spans, if RDPS of 300 ps/nm and 1,320 ps/nm are concentrated in 5th-13th fiber spans and 6th-13th fiber spans, respectively, then the best performance is obtained. It is also confirmed that optimal net residual dispersion (NRD) controlled by precompensation and postcompensation are 10 ps/nm and -10 ps/nm, respectively, in all two cases, and the effective launching power range below 1 dB eye opening penalty (EOP) in the concentrated RDPS of 300 ps/nm and 1,320 ps/nm are improved by 2 dB and 6 dB than optical transmission links with the uniformly distributed RDPS, respectively.

• Journal of Biosystems Engineering
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• v.36 no.3
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• pp.217-222
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• 2011

This study was carried out in order to reduce the amount of underground water which is used in the double layered single span plastic greenhouse for retaining heat. For this research, two plastic green houses of the double layered single span plastic greenhouse were installed. There was equipped of internal small tunnel for keeping warm air in the interior of the house. Then the internal small tunnel for keeping warm air was fitted with PVC duct of 50 cm in diameter filled with subsurface water. The surplus solar energy in the greenhouse was stored in the water in the PVC duct. Four FCUs (Fan Coil Unit), which has the capacity of 8,000 kcal per hour, were installed in the middle of the house, and a circulation motor in heat storage water tank was operated from 10:30 a.m. to 16:00 p.m. in order to circulate water between the water tank and the FCUs. Consequently about 5 degrees celsius could be maintained in the interior of the internal small tunnel for keeping warm air with the external temperature of lower than minus 5 degrees celsius. It appeared that the alteration of an internal temperature of the house was flexible depending on the sunlight during daytime. To prevent the water freezing, mixing antifreezing liquid in the water or operating FCU continuously was needed. Also, in order to use the surplus solar thermal energy on plastic green house of water curtain system efficiently, storing the surplus heat during daytime simultaneously finding a method of using water curtain systematic underground water happened to be important. As a result of this research, when the house's interior temperature is below zero the operation of FCU appeared to be impossible. Considering the amount of water used in the house with water-curtain-heating system is 150~200 ton per day, using the system mentioned in this research showed that reducing the underground water more than 80% in order to maintain the internal temperature as the level of 5 degree celsius at the extreme temperature of minus 5 degrees celsius.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.602-611
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• 2013

We have investigated the influence of system composition and preparation conditions on the particle size of vitamin E acetate (VE)-loaded nanoemulsions prepared by PIC(phase inversion composition) emulsification. This method relies on the formation of very fine oil droplets when water is added to oil/surfactant mixture. The oil-to-emulsion ratio content was kept constant (5 wt.%) while the surfactant-to-oil ratio (%SOR) was varied from 50 to 200 %. Oil phase composition (vitamin E to medium chain ester ratio, %VOR) had an effect on particle size, with the smallest droplets being formed below 60 % of VOR. Food-grade non-ionic surfactants (Tween 80 and Span 80) were used as an emulsifier. The effect of f on the droplet size distribution has been studied. In our system, the droplet volume fraction, given by the oil volume fraction plus the surfactant volume fraction, was varied from 0.1 to 0.3. The droplet diameter remains less than 350 nm when O/S is fixed at 1:1. The droplet size increases gradually as the increasing the volume fraction. Particle size could also be reduced by increasing the temperature when water was added to oil/surfactant mixture. By optimizing system composition and homogenization conditions we were able to form VE-loaded nanoemulsions with small mean droplet diameters (d < 50 nm). The PIC emulsification method therefore has great potential for forming nanoemulsion-based delivery systems for food, personal care, and pharmaceutical applications.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.156-163
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• 2002

Hollow core slabs generally have not been used for a bridge or a parking slab in Korea. In this study, high performance hollow core slabs, which have been the most thick one in domestic are re-designed and examined for practical use. Flexural tests were performed on four 315mm deep hollow core slabs to investigate adaptability for high vehicle live loadings and composite action with topping concrete. The precast slabs were pre-tensioned with ten strands of 1/2 inch diameter at the lower of slab and four strands of 1/2 inch diameter at the upper of slab, and cast with 80 mm deep topping concrete. Tested hollow core slabs showed ductile failure behaviors which were conformed to the current Ultimate Strength Design Method for a span of 10m up to the live load of 1,000 kgf/㎡. The rectangular md round shear cotters which were used for the composite action between precast and topping concrete, developed sufficient strengths because cracking, even micro had not been developed at the end of slabs up to the pure flexural tensile failure.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.193-197
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• 2000

Wolbachia, vertically transmitted bacterial endosymbionts, is known to induce cytoplasmic incompatibility (CI), parthenogenesis, or feminization in some insect species. The Wolbachia found to exist symbiotically as a non-virulent form in Drosophila melanogaster, however popcorn is a lethal strain of Wolbachia, which causes tissue degeneration and early death of its adult host. Popcorn-infected flies showed the delayed duration of an egg and larvae, and their pupal period and life span reduced. The oviposition and egg-hatching rate of popcorn-infected flies were decreased 15% and 80%, respectiv~ly, compared to those of the normal Wolbachia-infected flies. The pupation and emergence rates of popcorn-infected flies were 67% and 65%, respectively. When popcorn-infected flies were crossed with Wolba-chia-infected flies, and vice versa, both crosses resulted in a significant reduction in egg production, egg¬hatching, pupation, and emergence rate, and their progeny revealed the popcorn syndrome. When popcorn-infected male flies were crossed with uninfected females, popcorn was not detected in their progeny. Popcorn also maternally transmitted in flies, but it did not induce CI and affected on its host life cycle as a virulence.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1757-1763
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• 2014

Optical wavelength division multiplexing signals of eight non-return-to-zero 10 Gb/s channels were transmitted on the long-haul link up to 720 km. The link span was composed of 80 km single mode fiber, dispersion compensation fiber for complete compensation, and EDFAs. A circulating loop method was applied to the link experiment and the loop was optimized for the transmission link. Wavelength-dependent gain variation of EDFA was compensated using EDFAs of opposite gain slopes without expensive gain flattening filters. Average OSNR was aggravated to 22 dB and the worst OSNR channel variation was 9.7 dB after the transmission. It was confirmed by analyzing optical spectra that this OSNR variation was mainly caused by the hole burning effect of EDFA.

• Advances in nano research
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• v.16 no.6
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• pp.593-600
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• 2024

The nanoemulgel was prepared to induce a synergistic effect along with higher efficacy. Nine sets of macroemulsion were made in which liquid paraffin was stabilized by the two non-ionic surfactants, Tween® 80 and Span® 80. Comparative stability analysis of the macroemulsions was used to determine the effective surfactant concentrations that gave the most stable systems (NE 2, NE3, NE4, NE5). High-speed homogenization was then applied. The final formulation was evaluated for globule size and polydispersablity index, physical properties (color, homogeneity, consistency, syneresis), pH, viscosity, spreadability with 200 g and 500 g weight, conductivity, drug content, stability, skin irritation, antifungal efficacy. Zeta size analysis confirmed the nanosize of the droplets in NE2 (284.8 nm), NE3 (79.89 nm), NE4 (194 nm) but not NE5 (632.8 nm), which was outside the nanoemulsion range. The antifungal assay exhibited zone of inhibition for NE3 (43±1.0 mm) and NE4 (42±1.7 mm), a marketed cream (33±1 mm), fluconazole alone (35±1 mm) and terbinafine alone (35.0±1.7 mm). The zone of inhibition of nanoemulgels increased compared with the drugs when used individually and when compared a placebo.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.273-281
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• 2016

In this study, after carrying out a bending test that targeted the frames of plastic film greenhouse, the load-displacement relationship was analyzed to be used as basic data to develop greenhouse construction and maintenance guidelines. As a result, regardless of the shapes of the specimen, the yield and the maximum load increased as the size of the specimen increased. The displacement also showed the same pattern. A steel pipe showed lower yield and maximum load than a square pipe, and the displacement was large. In the steel pipe case, the displacement under the yield and maximum load was in the range of approximately 1.42-4.20mm and 5.80-24.13mm, respectively. In the square pipe case, the displacement under the yield and maximum load was in the range of approximately 1.62-3.00mm and 3.13-8.01mm, respectively. Further, a large difference was observed between the result of this test and the values calculated by a conventionally provided standard. In particular, not much difference was found from the result of this test in the case of a purlin member from the values provided by previous researches. However, a large difference was observed in the column or main rafter members. Furthermore, when a wide-span and venlo type, which is a glasshouse, was used as a target(h/100 and h/80), the displacement under the yield and maximum load was approximately 28.0mm and 35.0mm, respectively, which showed a large difference compared with the Netherlands standard(14.0mm) of a glasshouse. Further, in the main rafter case, a large difference was observed in the displacement limit according to the width(i.e., span) of the greenhouse where members are used. Therefore, because the displacement limit can vary depending on various factors such as type, form, and size of a greenhouse, we determined that studies or tests that consider these factors should be carried out to reflect them in the construction and maintenance of greenhouses.

• The Journal of Internal Korean Medicine
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• v.35 no.4
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• pp.455-471
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• 2014

Objectives: This experiment was done for investigating antimicrobial activity of Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, Gardenia Jasminoides extract against Staphylococcus aureus. Methods: After administering S. aureus on a bacterial culture media plate, antimicrobial activity was tested by dripping $80{\mu}l$ diluted Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, and Gardenia Jasminoides extract (100%, 50%, 10%, 1%) on plates that were cultivated for a span of time from 16 to 72 hours. Also, minimal inhibitory concentration (MIC) was tested by dripping the minimum dilution density solution that has antimicrobial activity between $80{\mu}l$ and $20{\mu}l$ ($80{\mu}l$, $60{\mu}l$, $40{\mu}l$, $20{\mu}l$) in measure of density. Antimicrobial activity of Hwangryunheadok-tang and four kinds of extracts against S. aureus was continually displayed. Results: 1. S. aureus (Standard Microorganism, ATCC) (1) Antimicrobial activity was displayed for Hwangryunheadok-tang, Scutellariae Radix extract, and Phellodendri Cortex extract respectively in the undiluted solution and 50% of diluted magnification. Gardenia Jasminoides extract showed its activity only in the undiluted solution; Coptis Rhizoma extract showed its activity down to 10% of diluted magnification. The antimicrobial activity of the undiluted solution was increased when the volume of inoculation increased. But, there was no difference when time was extended for cultivation. (2) MIC of Hwangryunheadok-tang, Scutellariae Radix extract was 50%, $20{\mu}l$. Coptis Rhizoma extract was 10%, $20{\mu}l$, Phellodendri Cortex extract was 50%, $80{\mu}l$ and Gardenia Jasminoides extract was 100%, $60{\mu}l$. 2. S. aureus isolated from diarrheal patients (1) When compared to standard microorganism, MIC has decreased. As a result, their antimicrobial activity has increased. (2) Antimicrobial activity of Hwangryunheadok-tang and four extracts was continually shown in extending of the time, 16, 24 and 72 hours. Conclusions: The author comes to the conclusion that Hwangryunheadok-tang, and four kinds of extracts have antimicrobial activity against S. aureus. Especially, when comparing standard microorganisms with S. aureus isolated from diarrheal patients, some cases showed that antimicrobial activity of all the extracts were better than antibiotics. Thus, if a further study is performed, the use of Hwangryunheadok-tang, and four kinds of extracts will be valuable and beneficial in clinical treatments.