• The Korean Journal of Mycology
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• v.8 no.1
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• pp.59-62
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• 1980

Investigation on modification of aflatoxin structures by Pseudomonads was attempted as a biological detoxifiying process of mycotoxins. Firstly, when any variation of aflatoxin yield of Aspergillus parasiticus in a mixed culture with Pseudomonas aeruginosa was examined, there was no noticible effect by growth of Pseudomonads on aflatoxin yield of Asperillus sp. Secondly, when capacity of Pseudomonas aeruginosa utilizing aflatoxin as a carbon source for its growth was tested, there was some indication that aflatoxin might be used for growth of Pseudomonads. It was also noticed that the residual aflatoxin showed different migrating pattern compared with that of the intact aflatoxin by thin layer chromatography. Thirdly, the cell-free extract prepared from Pseudomonas aeruginosa grown in a glucose minimal medium supplemented with aflatoxin and the intact aflatoxins were incubated in the presence of $Mg^{++}$. After a certain length of incubation period, the reaction mixtures were applied on TLC plates. As a result, aflatoxins in the reaction mixture migrated differently as the control did. Such results may indicate that some changes of aflatoxin properties were induced by Pseudomonads.

• Korean Journal of Microbiology
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• v.14 no.4
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• pp.176-185
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• 1976

An improved procedure for the rapid purification of glucose-6-phosphate dehydrogenase from extracts of Saccharomyces cerevisiae was developed by using affinity chromatography. Among six affinty media tested, NADP$^{+}$-agarose and Affi-gel Blue were more effective than others (i.e., Affi-gel Red, AMP-agarose, ATP-agarose, and NAD$^{+}$-agarose). Conditions to desorb the enzyme bound to the affinity media were examined to increase the purity as well as yield. The best result was obtained when the column was developed with a linear gradient of KCl (0-1.0M). In case of Affi-gel Blue, introduction of NAD$^{+}$ (15mM) washing step prior to the salt gradient was most effective to remove NAD$^{+}$-binding proteins. For a large scale preparation of G-6-P dehydrogenase higher recovery was obtained by Affi-gel Blue than NADP$^{+}$-agarose, however, the purity of the enzyme was decreased by 10 times if the former was used as the affinity medium. The capacity of Affi-gel Blue for G-6-P dehydrogenase was found to be 5 times higher than that of NADP$^{+}$-agarose. Furthermore Affi-gel Blue could be reused repeatedly and its preparation is relatively easier and less expensive than NADP$^{+}$-agarose.X> +/-agarose.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.1012-1014
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• 2013

DNA-DNA hybridization method with four oligonucleotide-specific probes was used simultaneously for differentiation and identification of four Mycobacterium species (Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii). This DNA-DNA hybridization method with 4 oligonucleotide-specific probes, which targets in the rpoB region of 4 Mycobacteria species, respectively, was tested on 322 clinical isolates. Using DNA-DNA hybridization method, we detected M. tuberculosis (282 strains), M. avim (7 strains), M. intracellulare (9 strains), and M. kansasii (3 strain) from 322 clinical isolates. This result was compared with conventional biochemical test and rpoB DNA sequence analysis of this clinical isolates. We confirmed identification of Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii with high sensitivity (100 %) and specificity (100 %). This DNA-DNA hybridization method could be performed within 4 hours at least. Therefore, we suggest that DNA- DNA hybridization method using 4 rpoB DNA probes of Mycobacteria could be used for accurate, rapid, convenient detection and identification of Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii in clinical samples.

• KSBB Journal
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• v.15 no.2
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• pp.214-218
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• 2000

A hepatitis B Surface Antigen(HBsAg)-screening kit using immunochromatographic assay(ICA) method was developed by e employing two kinds of antibodies. One is mouse monoclonal anti-HBs for tracer antibody and the other is goat p이yclonal a anti-HBs for capture antibody. This capture antibody was immobilized on the surface of nitroceliulose(NC) membrane and the t tracer antibody was conjugated with g미d particles. When serum sample was added to the sample well, the $\infty$njugates d deposited in a dry state on the surface of glass fiber filter were reconstituted and then combined with HBsAg in serum. In 5 5 min after adding, the assay result was visible through the window, that is, the complexes composed of HBsAg and the c conjugates appeared as maroon line on the lower part of the NC membrane. The detection limit of the ICA kit was 2 ng/ml w when being tested with the reference HBsAg.

• KIEAE Journal
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• v.17 no.3
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• pp.107-112
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• 2017

Purpose: Both silica gel and activated carbon black particles were adopted for use as PCM absorbed porous media applicable as construction materials. To investigate usable methods for absorbing PCM into the media, they were soaked into PCM and also tested for enhancement of PCM absorption into them. Method: To test PCM absorption into some porous media such as both ${\varphi}1{\sim}2mm$ and $10{\mu}m$ silica gels, and $50{\mu}m$ activated carbon black, $43^{\circ}C$ PCM was used as a laten heat material. The method, soaking into PCM was applied to this study, and the media were moderately rotated by centrifuge to have the extra PCM flow out. DSC analysis was conducted to investigate the melting and solidifying of the PCM absorbed into the porous media. Result: It was found that PCM was absorbed into the porous media by over 85 wt% of all particles. In addition, it was noted that the ultrasonic vibrator was accelerating the PCM absorption into the particles to three times higher speed than simple soaking. Centrifuge was adopted to remove extra PCM sticking on the particle surfaces and extra PCM was moderately removed from the surfaces of the particles. DSC analysis indicated that the latent heat of the absorbed PCM particles was 160 J/g, and the melting temperature was approximately $40^{\circ}C{\sim}50^{\circ}C$.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.54-57
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• 2007

Urea-formaldehyde (UF) resin was formulated similarly to plywood resin in the laboratory. The synthesized UF resin adhesive was mixed with extender, filler and acid catalyst. The mixture contained 56.1% total solids and 43.9% water. The mixes was used to bond five Com-Ply types using Korean wood species. The Com-Ply made were tested for shear strength and wood failure according to KS F 3101 ordinary plywood as well as for bending strength per KS F 3104 particleboard. The performance test results showed good strength properties for all Com-Ply types made in this study. This result represented that the UF resin adhesive mix was adequate for bonding Com-Ply with domestic wood species.

• Journal of ILASS-Korea
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• v.14 no.3
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• pp.131-138
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• 2009

In the present study, spread-recoil behavior of a drop of shear-thinning liquid (xanthan solution) on a dry wall (polished stainless-steel plate) was examined and compared with that of Newtonian liquid (glycerin solution). Nine different kinds of xanthan and glycerin solutions were tested, including three pairs of xanthan and glycerin solutions, each having the same viscosity in low shear rate region ($10^{-2}-10^0\;l/s$). The drop behavior was visualized and recorded using a CCD camera. The maximum diameter and the spreading velocity of the xanthan drops turned out to be significantly larger and the time to reach their final shape was much shorter compared to the cases with the glycerin solutions, due to the smaller viscous dissipation resulted from lower viscosity in the higher shear rate region (>$10^0\;l/s$). As a result, the maximum diameters were measured to be larger than the predicted values based on the model proposed for Newtonian liquids, and the deviation was more pronounced with the solution with the larger viscosity variation. Consequently, viscosity variation with the shear rate was found to be a dominant factor governing the spread-recoil behavior of shear-thinning drops.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.14-20
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• 2012

Performance and anti-corrosion of cold forged fuel pumps and die-casting fuel pumps have been tested in this study. Ethanol with 10 ppm of acetic acid is applied for the anti-corrosion test for 250 hours. Performance test result shows that the pumping efficiency of the cold forged fuel pump is equivalent to that of the die-casting fuel pump. The cold forged lower housing has better quality against corrosiveness and finer metallic structure than the die-casting lower housing does.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.503-510
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• 2014

This study proposes a bi-directional interleaved current-fed resonant converter (CRC) with reduced size of the output filter for a fuel cell electric vehicle. The proposed CRC achieves zero-current switching turn on and off of switches and diodes and makes ripple current of the output capacitor theoretically zero. As a result, the cost and volume of the output capacitor are significantly reduced. The two-stage power conversion technique is also applied for wide input and output voltage range operations. A 2kW prototype of the proposed converter is built and tested to verify the validity of the proposed operation.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.1
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• pp.18-25
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• 2013

In this paper, a nonlinear controller based on adaptive back-stepping method is proposed for high performance operation of Interior Permanent Magnet Synchronous Motor (IPMSM). First, in order to improve the performance of speed tracking, a nonlinear back-stepping controller is designed. In addition, since it is difficult to achieve the high quality control performance without considering parameter variation, a parameter estimator is included to adapt to the variation of load torque in real time. Finally, for the efficiency of power consumption of the motor, controller is designed to operate motor with the minimum current for the required maximum torque. The proposed controller is tested through experiment with a 1-hp Interior Permanent Magnet Synchronous Motor (IPMSM) for the angular velocity reference tracking performance and load torque volatility estimation, and to test the Maximum Torque per Ampere (MTPA) operation. The result verifies the efficacy of the proposed controller.