• Korean Journal of Microbiology
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• 제39권4호
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• pp.267-271
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• 2003

Burkholderia sp. D5, a polyaromatic hydrocarbons(PAHs)-degrading bacterium, was isolated from oil-contaminated soil. The bacterium could utilize phenanthrene (Phe) as a sole carbon source but could not use pyrene (Pyr). However, the strain could degrade Pyr when a cosubstrate such as yeast extract (YE) was supplemented. The PAH degradation rate of the bacterium was enhanced by the addition of other organic materials such as YE, peptone and glucose. YE was a particularly effective additive in stimulating cell growth as well as PAH degradation. When 1 g-YE/L was supplemented into the basal salt medium (BSM) with 215 mg-Phe/L, the specific growth rate (0.28 h-1) and Phe-degrading rate (29.30 μmol/L/h) were enhanced approximately ten and two times more than those obtained in the BSM with 215 mg-Phe/L, respectively. Through kinetic analysis, the maximum specific growth rate (μmax) and PAH degrading rate (Vmax) for Phe were obtained as 0.34/h and 289 ${\mu}mol$/L/h, respectively. Also, μmax and Vmax for Pyr were 0.27 h-1 and 50 ${\mu}mol$/L/h, respectively. The degradation rates for each Phe (2.20 μmol/L/h) and Pyr (2.18 μmol/L/h) were lower in mixture substrates than in a single substrate (29.30 ${\mu}mol$/L/h and 9.58 ${\mu}mol$/L/h, respectively). Burkholderia sp. D5 can degrade Phe and Pyr contained in soil, and the PAH degradation rates in soil were 20.03 ${\mu}mol$/L/h for Phe and 1.09 ${\mu}mol$/L/h for Pyr.

• Journal of Plant Biotechnology
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• 제5권3호
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• pp.157-161
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• 2003

Proline is known as an osmoprotectant accumulating in response to salt and dehydration stresses. An increased level of proline is achieved by either an induced synthesis or a reduced degradation of proline. In an attempt to increase salt tolerance in carrot, a P5CS gene from mothbean was introduced via an Agrobacterium-mediated transformation. The resulting carrot cells and the regenerated plants containing the transgene showed increased levels of proline compared to nontransgenics. The transgenic cell line, Pj2 showed about 6 times increased degree of tolerance determined by relative growth after a treatment in 250 mM NaCl. In facts, due to the retarded growth shown in non-saline condition, Pj2 cells grow only about 1.2 times better than nontransgenic control under salt stress condition. Taken together, it appears that a P5CS is a key enzyme in proline biosynthesis and the increased accumulation of proline by overexpression of the enzyme is enough to enhance tolerance to salt stress in carrot.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.79-82
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• 2003

An ionomer is defined as an ion-containing polymer with a small amount (usually up to 10-15 mol%) of ionic groups along the backbone chains or as pendant groups. Ionomers have been extensively studied because of the significant changes in their physical properties due to the formation of ionic aggregates, such as enhanced mechanical properties, high melt viscosity, and increased thermal properties.$\^$1-5/ Although there have been many studies of ionomers, the crystallization behaviour of degradable ionomers is still not understood. (omitted)

• Korean Journal of Microbiology
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• 제21권2호
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• pp.86-94
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• 1983

Polygalacturonase of Byssochlamys fulva was purified and characterized. Specific activity increased from 2.21 units/mg protein to 10.47 units/mg protein through $(NH_4)_2SO_4$ treatment, SephadexG-100 gel filtration, and DEAE-Sephadex ion exchange chromatography. Divalent cations, such as $Ca^{++}\;and\;Cu^{++}$, increased polygalacturonase activity greatly. Added as $10^{-3}M$ concentration, $Ca^{++}$ ion enhanced enzyme activity 9.8folds. Optimum temperature was $50^{\circ}C$ and optimum pH was 5.0. Activation energy of reaction was 8.69 Kcal/mole. Michaelis-Menten $constant(K_M)\;and\;V_{max}$ of reaction were $6.27{\times}10^{-3}mole/l\;and\;2.85{$\mu}moles/min$. Polygalacturonase of Byssochlamys fulva preferred polygalacturonic acid to pectin as substrate and was presumed as endo-type on the basis of the relationship between viscosity reduction and substrate degradation. Molecular weight of polygalacturonase was estimated as 55,000.

• Journal of the Korea Institute of Military Science and Technology
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• 제16권2호
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• pp.191-198
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• 2013

Geo-pointing is a function that maintains LOS(Line of Sight) to a stationary ground target by controlling azimuth and elevation angles of a EOS(Electro-Optical System) which are calculated from aircraft navigation data and target coordinates. In design and implementation of the geo-pointing, a transmission time delay between GPS/INS and EOS is a major degradation factor of the geo-pointing performance when the aircraft is rapidly maneuvered especially. In this paper, a kalman filter is designed to compensate the transmission time delay of aircraft navigation data. Simulation and test results show that the geo-pointing performance is enhanced by the proposed compensation technique.

• Journal of the Korean Ceramic Society
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• 제53권3호
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• pp.343-348
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• 2016

Manganese and $TiO_2$ grown on Activated Carbon Fiber (ACF) was synthesized by hydrothermal method. The prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). The catalytic behavior was investigated through the decomposition of methylene blue (MB) and methyl orange (MO) as standard dyes under visible light. The degradation performance of the degraded standard dye solutions was determined by UV-Vis spectrophotometry. This enhanced photocatalytic activity arises from the positive synergetic effect among the Mn, $TiO_2$ and ACF in this heterogeneous photocatalyst. The process contributes to the release of abundant photocatalytic sites of Mn and $TiO_2$ and improves the photocatalytic efficiency. The excellent adsorption and photocatalytic effect with the explanation of the synergetic mechanism are very useful not only for fundamental research but also for potential practical applications.

• Journal of Korean Society of Water and Wastewater
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• 제9권2호
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• pp.127-135
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• 1995

The purpose of this study was to more fully evaluate the potential for chlorophenol degradation in anaerobic sludge. The pH effects on the ring cleavage of phenol and dechlorination of monochlorophenol isomers and dichlorophenl isomers. This study results are as follows ; Each of the monochlorophenol isomers were degraded in anaerobic sludge. The relatives rates were 2-Chlorophenol > 3-Chlorophenol > 4-Chlorophenol. Biodegradation results for the dichlorophenol isomers in anaerobic sludge are such as 2,3-dichlorophenol and 2,5-dichlorophenol was reductively dechlorinated to 3-chlorophenol, 2,4-dichlorophenol to 4-chlorophenol, 2,6-dichlorophenol to 2-chlorophenol. The two dichlorophenol isomers which did not contain an ortho Cl substituent 3,4-dichlorophenol and 3,5-dichlorophenol were persistent during the 6-week incubation. The rate of dechlorination was enhanced by the presence of a Cl group ortho, rather than para, to the site of dechlorination.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.152-155
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• 2002

In this paper, a new approach is proposed for the error detection dedicated to MPEG-4 video coding by using the digital watermarking. In the process of encoding, the proposed scheme abstracts the macroblock features of headers, motion vectors, and Discrete Cosine Transform (DCT) coefficients, which are embedded in the quantized DCT coefficients as the digital watermarks. The decoder performs the accurate error detection through the watermark extraction. Simulation results demonstrate that the error detection ability of the proposed approach can be significantly enhanced, and that digital watermark embedding incurs little degradation to the picture quality.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.52-55
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• 2000

The temperature effects of programming speed and endurance characteristics in p-channel flash memory cell have been investigated. In the case of room temperature, the programming speed of p-channel flash memory by using BTB scheme is faster than that by using CHE scheme. However, endurance characteristics with BTB programming scheme is not better than that with CHE programming scheme. In the case of elevated temperature, CHE programming speed is reduced due the gate current degradation but BTB programming speed is enhanced due to the increasing of gate current. Finally, the endurance characteristics of both schemes are improved due to the reduction of gate oxide traps.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.17-20
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• 2000

TCP is ill-suited to real-time multimedia applications. Its bursty transmission, and abrupt and frequent wide rate fluctuations cause high delay jitters and sudden quality degradation of multimedia applications. Deploying non congestion controlled traffic results in extreme unfairness towards competing TCP traffic. Therefore, they need to be enhanced with congestion control schemes that not only am at reducing loss ratios and improve bandwidth utilization but also are fair towards competing TCP connections. This paper proposes a differentiated rate adaptation algorithm based on loss and round trip time. Rate in a sender quickly responds to loss ratio and holds steady state. Additionally, this algorithm reduces loss ratio by loss prediction in a receiver.