• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1453-1458
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• 2011

This paper dealt with the measurement and analysis of electromagnetic waves generated by partial discharges in insulation oil to develop insulation diagnostic techniques for power transformer. Two types of narrow-band monopole antennas with the resonant frequency of 500 MHz and 1 GHz were designed and fabricated. We simulated defects which consist of a needle electrode with curvature radius of 10 ${\mu}m$ and a plane electrode with diameter of 60 mm in insulation oil. From the experiment, the maximum output voltage of the fabricated antennas was measured; 620 $mV_{max}$ for 500 MHz resonant frequency and 920 $mV_{max}$ for 1 GHz resonant frequency.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.256-260
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• 2004

Melanin was decolorized by lignin peroxidase from Phanerochaete chrysosporium. This decolorization reaction showed a Michaelis-Mentens type relationship between the decolorization rate and concentration of two substrates: melanin and hydrogen peroxide. Kinetic constants of the decolorization reaction were 0.1 OD$\sub$475//min ($V_{max}$) and 99.7 mg/L ($K_{m}$) for melanin and 0.08 OD$\sub$475//min ($V_{max}$) and 504.9 ${\mu}$M ($K_{m}$) for hydrogen peroxide, respectively. Depletion of hydrogen peroxide interrupted the decolorization reaction, indicating the essential requirement of hydrogen peroxide. Pulsewise feeding of hydrogen peroxide continued the decolorizing reaction catalyzed by lignin peroxidase. These results indicate that enzymatic decolorization of melanin has applications in the development of new cosmetic whitening agents.

• Analytical Science and Technology
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• v.11 no.2
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• pp.130-134
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• 1998

Polyamines were analyzed in young cotyledons of spring radish. The uptake rate of SPD were transported within 20 min lineary and reached the saturation phase after 1hr. The uptake rate of SPD decreased gradually with the time by the increasing amount of SPD inside the cells. The uptake of PA depends on the external pH. The optimal pH of PA uptake are pH 7.5. $K_m-$ and $V_{max}-$values depend on external pH also. The uptake rate of PA was inhibited by external KCI, which depolarized membrane potential in the cells.

• Journal of the Korea Furniture Society
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• v.20 no.3
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• pp.232-238
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• 2009

In designing furniture and interior accessories, a computer graphic program is normally used over the whole process of manufacturing furniture from idea stage to actual manufacturing stage. It especially play an important role in the modeling process which comes before actual manufacturing stage. in such modeling process, the most important part is expression of quality of material used and surface treatment method. Expression of material quality of wood and surface finishing just like an actual picture enable the designers to analogize the feeling of furniture and interior accessories more exactly over the whole process of actual manufacturing and such a result has positive effect on development field of furniture and accessories.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.195-200
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• 2008

Hydroxylated polychlorinated biphenyl (OH-PCBs)는 PCB의 CYP-dependent oxidation의 대사물로서 잠재적 독성이 강하고 지질친화성을 가지며 생물군에 지속적인 축적성을 나타낸다. OH-PCBs의 해독화 효능을 조사하기 위하여 channel catfish 간에서 glucuronidation을 통한 해독작용 가능성을 평가하고 biphenyl 구조에 다양한 염소치환의 구조적 차이점에 따른 영향을 비교 분석하여 보았다. Kinetic parameters에서 $K_m$과 $V_{max}$는 $192{\sim}871{\mu}M$, $869{\sim}1774$ pmo1/min/mg으로써 4'-OH-PCB35와 4'-OH-PCB69이 가장 높은 속도의 glucuronidation을 나타냈으며, 구조적 차이점에서 phenolic group에 한 개의 염소치환이 존재할 경우보다 두 개의 염소치환이 존재할 경우에 OH-PCBs(p<0.001)의 glucuronidation에 대한 $V_{max}$를 현저하게 낮추는 결과를 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.231-234
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• 1998

In this study, the wind-mill type ultrasonic motor was fabricated, and then resonant frequency and vibration velocity characteristics of the stator were measured. Brass metal was pressed with umbrella-type using metal mold, then slot of 4 kind was processed in each of thickness. Among sixteen's stators, resonant frequency on vibration velocity was decreased remarkably in stator of higher resonant point, but resonant frequency on vibration velocity wasn't almost changed at lower resonant point of stator. The thickener thickness of elastic body, vibration velocity was decreased. The more slot of elastic body, vibration velocity was increased Applied voltage was changed from 10$V_{max}$ to 100$V_{max}$. Maximum vibration velocity value was 2.0[m/s].

• Food Science and Biotechnology
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• v.14 no.2
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• pp.297-300
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• 2005

Effects of allyl sulfides on kinetic behavior of cytochrome P450 1 (CYP1)-catalyzed ethoxyresorufin O-deethylase (EROD) activity were studied using microsomes from benzo[a]pyrene-treated human hepatoma cells. Apparent $K_m$ and $V_{max}$ values were calculated as $2.8\;{\mu}M$ and $3.0\;{\mu}mol$ resorufin/min/mg protein based on Lineweaver-Burk plot of microsomal EROD activity, respectively. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) affected $K_m$ and $V_{max}$ values of EROD activity and acted as mixed-type inhibitors for CYP1 isozymes. Apparent Ki values of DADS and DATS were calculated as 1.07 and 0.88 mM, respectively, by re-plotting slopes of Lineweaver-Burk plot and inhibitor concentrations.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.471-478
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• 2000

The pharmacokinetic properties of KR-V compounds, recently developed as new anti-HIV agents, were studied after i.v. and p.o. administration in rats. The concentrations of the KR-V series were determined in rat plasma using an high-performance liquid chromatography (HPLC)-UV detection system. Of the 19 KR-V compounds investigated in the present study, only KR-V 3, 10, 14, 16 and 18-1 showed oral bioavailability. The plasma concentration-time data could be adequately described by an one-compartment open model. In the i.v. kinetic study (10mg/kg), the CLt of KR-V 3, 10, 14 and 16 (>4L/hr/kg) were significantly higher than that of KR-V 18-1 (1.1 L/hr/kg). The AUC of KR-V 18-1 was greater ($8.97{\mu}g{\cdot}hr/ml$) than that of the other compounds, but the Vd (0.58 L/kg) was lower. In the p.o. kinetic study (50mg/kg), although the t-1/2 of KR-V 18-1 was shorter than that of the other compounds, the AUC ($3.659{\mu}g{\cdot}hr/ml)$ and $C_{max}(1.891{\mu}g/ml$) were markedly higher. In a seperated in vitro experiment, only KR-V 18-1, of the 5 compounds with bioavailibility, exhibits potent activity against HIV-1 mutant strains. Therefore, KR-V 18-1 is expected to become a new potent anti-AIDS drug candidate/lead compound.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.549-559
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• 2009

The objectives of this study are to investigate the biomineralization of goethite and lepidocrocite formed on the twisted-stalk and the sheathed-filament structure that is suggest microbe origin, and heavy metal in the yellow Fe-hydroxide. On the ratio of Cl and the Cl/Br ratios that are a pollution and non-pollution of groundwaters, it is indicated that the groundwater in this areas were relatively contaminated by human activity. The composition of the yellow Fe-hydroxide consisted mainly of $Fe_2O_3$ and $SiO_2$. The content of $Fe_2O_3$ ranges from 58.57 wt.% to 75.7 3wt.%, and $SiO_2$ content ranges from 5.8 wt.% to 16.17 wt.%. Heavy metal elements such as Zn(max. 6,160 mg/kg), Pb(max. 377 mg/kg), U(max. 503 mg/kg), Cr(max. 203 mg/kg), Cu(max. 77 mg/kg), V(max. 162 mg/kg), Ni(max. 105 mg/kg) were observed to be rich in those yellow Fe-hydroxide. The lath and platy crystals and needle-shaped crystals were clearly observed on the twisted-stalks and sheathed-filaments structure. The goethite, gypsum, and lepidocrocite were identified in the yellow Fe-hydroxide by x-ray powder diffraction.