• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.53-59
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• 2014

To evaluate the inhibitory effect of xanthine oxidase (XO) and aldehyde oxidase (AO), and antihyperuricemic effect by Aspergillus oryzae fermented Smilax china L. leaf extracts and fractions, we observed extracted yield by each solvent, the content of total polyphenol and total flavonoid (TF), the activities of XO and AO, and serum uric acid level. Extracted yield (g/kg) by 80% ethanol (EtOH) was 13.56, those of n-hexane, dichloromethane (DICM), ethylacetate (EtOAc) and n-butanol fraction (BuOH) were 1.35-3.33. Furthermore, total polyphenol content (mg/g-extract) of EtOAc fraction, BuOH fraction, DICM fraction and EtOH fraction is 478.07-501.26, 259.49-289.02, 165.03-232.27, 134.02-196.54, respectively. Those of fermented EtOAc and DICM fraction was 4.85 and 40.74% higher than that of non-fermented fraction, respectively, while the other fermented fractions were lower than those of non-fermented fractions. And total flavonoid content (mg/g-extract) of EtOAc fraction was higher than those of other fractions. Additionally, TF of fermented EtOAc and BuOH fraction is 10.56 and 60.17% higher, than that of fermented fraction, respectively, although those of the other fermented fractions was lower than that of non-fermented fractions. On the other hand, XO inhibitory activities of all fermented fractions was significantly higher than that of all non-fermented fraction, while those of fermented EtOAc (75.02%) and BuOH fraction (65.59%) was markedly higher than that of non-fermented fraction (39.42 and 5.34%), respectively. In addition, AO inhibitory activities of DICM and EtOAc fraction was 81.82 and 77.93% higher, respectively, than those of the other fractions, and those of fermented fractions as with XO were significantly higher than that of non-fermented fractions. Meanwhile, serum uric acid level (SU) of hyperuricemic control mice (HC, 6.98 mg/dL) was 1.83 folds higher than that of normal control (NC, 3.82 mg/dL). Furthermore, SU in the group treated with EtOAc fraction decreased in a dose dependent manner compared with the allopurinol control group, although those of fermented fractions were significantly lower than those of non-fermented fractions. This study suggests that fermented Smilax china L. leaf extracts may regulate the XO and AO inhibitory activities and antihyperuricemic effect due to aglycone components from glycoside form flavonoids by fermentation of A. oryzae.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.898-904
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• 2007

This paper presents the generalized and explicit expressions for evaluating the performance of the multi-phase interleaved boost converter (IBC) operating in discontinuous inductor current mode (DICM). The full order averaged model is derived. The generalized transfer functions of interest are presented and the dynamic characteristics are analyzed. The generalized analysis of converter performance is verified through the experimental and simulation results.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.778-780
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• 2005

This paper presents the steady-state characteristics of the multi-phase interleaved converters in discontinuous inductor current mode(DICM). The full-order averaged model is derived, and the conversion ratio and efficiency are presented.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.11a
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• pp.107-111
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• 2001

This paper presents a detailed analysis method of the universal input forward converter with LC input filter operating in discontinuous capacitor voltage mode(DCVM) for wind power generation. In this analysis, condition for DCVM operation and conversion ratio for rectified sinusoidal input are made clear. To verify the validity of the analysis, simulation is carried out for the universal input ranging from 90 $V_{rms} to 260 V_{rms}$

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.518-529
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• 2000

A detailed and thorough parametric study of digital image correlation method is presented. A theoretical background and development of the method were introduced and the effects of various parameters on the determination of displacement outputs from the raw original and deformed image information were examined. Use of the normalized correlation coefficient, the use of 20 to 40 pixels for a searching window side, 6 variables searching, bi-cubic spline sub pixel interpolations and the use of coarse-fine search are some of the key choices among the results of parametric studies. The displacement outputs can be further processed with two dimensional curve fitting for the data noise reduction as well as displacement gradient calculation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.506-510
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• 2004

A multi-phase interleaved buck converter is used to reduce current ripples and filter size of a power supply. This paper addresses the modelling and steady-state analysis of the multi-phase interleaved buck converter operated in discontinuous inductor current mode. The model is derived using an averaging technique in steady state. The do voltage ratio and the range of the discontinuous inductor current mode(DICM) and the continuous output current mode(COCM) are derived from the averaged state-space model. In addition, the efficiency is investigated according to the number of phase.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.123-130
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• 2007

This paper presents the generalized and explicit expressions for evaluating the performance of the multi-phase interleaved buck converter (IBC) operating in discontinuous inductor current mode (DICM). The full-order averaged model is derived. The generalized transfer functions of interest are presented and the dynamic characteristics are analyzed. The generalized analysis of converter performance is verified through the experimental and simulation results.