• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.835-840
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• 2010

This study develops a variable structure controller using nonlinear surface instead of the fixed, which has been the robustness against parameter variations and extraneous disturbance during the reaching phase. reaching time of the system trajectory is faster than the fixed method. This proposed scheme has better performance than the conventional method in reaching time, parameter variation and extraneous disturbance. The effectiveness of the proposed control scheme is verified by simulation results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.281-284
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• 1983

Interrelationship between. certain physicochemical properties of milled rice was investigated. Grain hardness and milling time were correlated with grain dimension. Equilibrium moisture content of rice upon soaking at room temperature showed a high negative correlation with the amylose content. The contents of protein, fat and ash had no relationship with hardness, milling time and equilibrium moisture content.

• Korean Journal of Animal Reproduction
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• v.25 no.1
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• pp.19-28
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• 2001

The present study was undertaken to investigate the effects of cooling rate and equilibration time on the survival, in vitro maturation and development to embryos of frozen-thawed bovine immature oocytes(Germinal Vesicle Stage). The cryoprotectants are used 10% ethylene glycol(EG) as permeating cryoprotectant and 0.05M soc.ose(S) or trehalose(T) as low molecular weight nonpermeating cryoprotectants and 5% ficoll(F) or polyvinylpyrrolidone(PVP) as high molecular weight nonpermeating cryoprotectants. Four freezing solution were uysed in this experiment(EFT: 10% EG + 5% F + 0.05M T, EFS: 10% EG + 5% F + 0.05M S, EPT: 10% EG + 5% P + 0.05M T, EPS: 10% EG + 5% P + 0.05M S). The best equilibration time and freezing solution was 15 min in EPT(83% survival rate of frozen-thawed bovine immature oocytes). When frozen-thawed bovine oocytes were cultured following IVM and IVF, there was no significant difference in cleavage and development rates among the EFT, EFS, EPT and EPS solutions. When 9 blastocysts derived from frozen bovine oocytes were transferred to 6 recipients, two recipients were pregnant. And one was aborted at 45 days of pregnancy and the other had a stillbirth.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.111-117
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• 1989

Six cigarette brands produced in Korea and U.S.A. were studied to find the effects of relative humidity, moisture sorption time, temperature, and the amounts of water extracts and total sugar in the brands on the equilibrium moisture contents. The equilibrium contents were higher in the domestic brands than foreign ones and the sorption rates of moisture were faster in the domestic cigarettes. The Korean brands with high contents of water extracts and total sugar had higher equilibrium moisture contents in the range of RH 40-80% at $20^{\circ}C$ for 72hours. These are the reasons that Korean brands contain higher ratio of flue-cured tobacco and American brands are blended with higher ratio of Burley tobacco.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.288-298
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• 1995

Load balancing attempts to improve the performance of a distributed computing system by transferring some of the workload of a congested site to others. A load balancing scheme that supports both the source-initiated and the server- initiated load balancing is proposed in this paper. It can model both the m/m/1 queue(no load balancing) and the m/m/n queue(perfect load balancing) as the extreme State variables are replicated into every site, and copy consistency constraints are relaxed more weakly. We propose weak copy consistency constraints which correlate the outdated state information to that of the current state. We also derive sufficient conditions under which each scheduler can guarantee the load balancing without communication Using this model, the problem of load balancing is converted to that of maintaining the consistency of states and communication overhead becomes less than that of the bidding algorithm. The scheme is simulated by event tracing, compared to the two extreme cases and the bidding algorithm. The results show that the mean response time and the number of messages are reduced by 0-35% and 40-100% respectively, compared with the bidding algorithm. Finally the effects of some system parameters are described.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.46-53
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• 2009

Phase equilibrium and dynamic behavior studies were performed in systems containing $C_{12}E_5$ nonionic surfactant solution and nonpolar hydrocarbon oil. The phase behavior result showed an oil-in-water(O/W) microemulsion(${\mu}E$) in equilibrium with excess oil phase at low temperatures and a water-in-oil(W/O) ${\mu}E$ in equilibrium with excess water phase at high temperatures. For intermediate temperatures a 3 phase region containing excess water, excess oil, and a middle-phase microemulsion was observed and the transition temperature was found to increase with an increase in the chain length of a hydrocarbon oil. Dynamic behavior at low temperatures showed that an oil drop size decreased linearly with time due to solubilization into micelles and the solubilization rate decreased with an increase in the chain length of a hydrocarbon oil. On the other hand, both spontaneous emulsification of water into oil phase and expansion of oil drop with time were observed because of diffusion of surfactant and water into oil phase. Under conditions of a 3 phase region including a middle-phase ${\mu}E$, both rapid solubilization and emulsification of oil into aqueous surfactant solution were found mainly due to the existence of ultra-low interfacial tension. Interfacial tensions were measured as a function of time for n-decane oil drops brought into contact with 1 wt% surfactant solution at $25^{\circ}C$. Both equilibrium interfacial tension and equilibration time were found to increase with an increase in the chain length of a hydrocarbon oil.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.473-478
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• 2009

Phase equilibrium and dynamic behavior studies were performed on systems containing $C_{10}E_5$ nonionic surfactant solutions and nonpolar hydrocarbon oils. The phase behavior showed an oil in water (O/W) microemulsion (${\mu}E$) in equilibrium with excess oil phase at low temperatures and a water in oil (W/O) ${\mu}E$ in equilibrium with excess water phase at high temperatures. For intermediate temperatures a three-phase region containing excess water, excess oil, and a middle-phase microemulsion was observed and the transition temperature was found to increase with an increase in the chain length of a hydrocarbon oil. Dynamic behavior at low temperatures showed that an oil drop size decreased linearly with time due to solubilization into micelles and the solubilization rate decreased with an increase in the chain length of a hydrocarbon oil. On the other hand, both spontaneous emulsification of water into oil phase and expansion of oil drop were observed because of diffusion of surfactant and water into oil phase. Under conditions of a 3 phase region including a middle-phase ${\mu}E$, both rapid solubilization and emulsification of oil into aqueous solutions were found mainly due to the existence of ultra-low interfacial tension. Interfacial tensions were measured as a function of time for n-decane oil drops brought into contact with 1 wt% surfactant solution at $25^{\circ}C$. Both equilibrium interfacial tension and equilibration time increased with an increase in the chain length of a hydrocarbon oil.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.373-382
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• 2008

First reported geochemical characteristics of mantle xneoliths (spinel peridotites) from Sunheul-ri, Jeju Island, provide important clues for understanding the lithosphere composition, equilibrium temperature, and the period of entrainment and transport of the xenoliths in the host magma. Core and rim of mineral phases in the xenoliths are constant chemical compositions as $Fo_{89-90}$ of olivines. The ranges of equilibrium temperature, obtained by two pyroxenes geothermometer, are about $951{\sim}1035^{\circ}C$ for Sunheul-ri spinel peridotite xenoliths and are similar to the range of equilibrium temperatures for the xenoliths from other sites in Jeju island. The period of entrainment and transport of the xenoliths in the host magma of Sunheul-ri mantle xenoliths is about 42 days.

• Food Science and Preservation
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• v.9 no.4
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• pp.385-390
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• 2002

Functional activities of Lyophyllum ulmarium microwave-assisted extracts under different conditions including electron donating ability, tyrosinase inhibition activity and nitrite scavenging effect were examined. Total polyphenol content increased as increasing microwave power up to 90 W in the water extracts. Electron donating ability increased with microwave power up to 90 W in 50% ethanol extract and 99% ethanol extract. Tyrosinase inhibition activity and nitrite scavenging effect in the extract increased as microwave power increased during extraction. Total polyphenol content increased as extending extraction time up to 5 min in the water extract. But the highest electron donating ability and tyrosinase inhibition activity was obtained after 10 min extraction. Significantly higher total polyphenol content and electron donating ability were found in the water extract whereas greater tyrosinase inhibition activity and nitrite scavenging effect were observed in 99% ethanol extract. The maxium nitrite scavenging effect was found at pH 1.2 and decreased as pH increased.

• Food Science and Preservation
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• v.16 no.5
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• pp.719-725
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• 2009

We investigated the absorption characteristics of protein-bound polysaccharide powders of various molecular weights isolated from the mushroom Agaricus blazei Murill. The monolayer moisture content calculated using the GAB equation showed a higher level of significance than did the BET equation. The higher the water activity, the lower the isosteric heat of sorption. The fitness of the isotherm curve was shown to be in the order of the Khun, Oswin, Caurie and Henderson models. The prediction model equations for moisture content were established by use of ln(time), water activity, and temperature.