• Journal of Astronomy and Space Sciences
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• v.28 no.1
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• pp.9-12
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• 2011

Results of an analysis of 11 nights of R-filter CCD photometry data of an intermediate polar MU Camelopardalis (MU Cam) obtained at the Korean 1.0 m telescope at Mt. Lemmon are reported. After checking the spin period with our data, $P_{spin}=0.^d01373801(59)$, we compiled the reported data of maxima timing and an O-C diagram analysis has been carried out to understand the spin period variation. A significant spin period variation was detected, and fitting the O-C points to a cubic parabola led to an ephemeris of $BJD_{max}=2453682.4178(94)+0.0137380(13)E-2.07(55){\times}10^{-11}E^2+2.28(52){\times}10^{-15}E^3$. The torque experienced by the magnetic compact star accreting in a disk is estimated as ${\tau}{\approx}1.815{\times}10^{35}gcm^2/s^2$ in a simple approximation in order to show how important monitoring the period variation is. Thus we conclude that monitoring the long-term spin period variation will help to understand the physical condition of magnetic compact stars.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.181-187
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• 2015

In this study, the methanol fraction and aglycone fraction were made from Gynura procumbens (G. procumbens) extracts and their antioxidative effects were investigated. The free radical scavenging activity (1,1-diphenyl-2-picrylhydrazyl, DPPH), total antioxidant capacity by luminol-dependent chemiluminescence assay, and the protective effects against reactive oxygen species (ROS) in erythrocytes were measured to evaluate the antioxidative activities of the extracts. Free radical scavenging activities ($FSC_{50}$) of the methanol fraction and aglycone fraction were 90.25 and $81.38{\mu}g/mL$, respectively. Total antioxidant capacities ($OSC_{50}$) of the methanol fraction and aglycone fraction were 16.96 and $12.30{\mu}g/mL$, respectively. The free radical scavenging activity and total antioxidant capacity of the aglycone fraction were greater than those of methanol fraction. The cellular protective effect on the $^1O_2$-induced cellular damage of human erythrocytes was confirmed by ${\tau}_{50}$ value. The ${\tau}_{50}$ value of the methanol fraction and aglycone fraction were 36.7 min and 76.1 min, respectively in $5{\mu}g/mL$, and the aglycone fraction showed about 2 times higher cellular protecive effect than (+)-${\alpha}$-tocopherol (35.4 min). These results indicate that the aglycone fraction of G. procumbens extracts has application possibility as antioxidant ingredient of cosmetic.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1065-1070
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• 2005

$[Mn_{12}O_{12}(O_2CPh-4-SMe)_{16}(H_2O)_4]{\cdot}7CH_2Cl_2$ (1), a new single-molecule magnet complex has been successfully synthesized by substitution of acetate ligand of Mn12ac with 4-(methylthio)benzoic acid. Complex 1 crystallizes into triclinic P$\overline{1}$ with a = 18.321(3) $\AA$, b = 19.011(3) $\AA$, c = 27.230(4) $\AA$, $\alpha$ = 86.973(3)$^{\circ}$, $\beta$ = 76.919(3)$^{\circ}$, $\gamma$ = 87.613(3)$^{\circ}$, and Z = 2. In complex 1, one Mn(III) ion has an abnormal Jahn-Teller elongation axis oriented at an oxide ion. Complex 1 has two out-of-phase ac susceptibility peaks in the 2-4 K and 4-7 K regions. Effective anisotropy energy barrier and pre-exponential factor are $U_{eff}$ = 45.95 K, 1/$\tau$0 = 8.6 ${\times}\;10^9s^{-1}\;for\;{\chi}_M$'' peaks in the lower temperature region and $U_{eff}$ = 59.45 K, 1/$\tau_0$ = 2.2 ${\times}\;10^8\;s^{-1}$ for $\chi_M$'' peaks in the higher temperature region. The parameters of S = 10, g = 1.87, D = -0.40 $cm^{-1}$, and E = 0.00034 $cm^{-1}$ were obtained from the M/N${\mu}_B$ vs. H/T plot of complex 1.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.255-263
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• 2017

In this study, the antioxidant activities, cellular protective effects, and inhibitory effects on elastase of non-fermented and fermented extracts of Parthenocissus tricuspidata (P. tricuspidata) stem using Lactobacillus pentosus were investigated. The free radical scavenging activities ($FSC_{50}$) of non-fermented and fermented extracts were 42.3 and $34.5{\mu}g/mL$, respectively, in which the activity after fermentation was approximately 18.4% higher. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) in $Fe^{3+}-EDTA/H_2O_2$ system of non-fermented and fermented extracts were 2.6 and $2.5{\mu}g/mL$, respectively. The activity after fermentation was approximately 4.2% higher. In the $^1O_2$-induced cellular damage of erythrocytes, the cellular protective effects (${\tau}_{50}$) of non-fermented and fermented extracts were 126.4 and 173.0 min at $50{\mu}g/mL$, respectively. The activity after fermentation was approximately 34.0% higher. The effect of fermented extract was 3.9 times higher than $(+)-{\alpha}$-tocopherol (${\tau}_{50}=43.4min$), known as a lipophilic antioxidant at $50{\mu}g/mL$. The inhibitory effect of elastase was investigated to predict the anti-wrinkle efficacy using Hs68 human fibroblasts cells. The elastase inhibitory activities ($IC_{50}$) of non-fermented and fermented extracts were 873.6 and $687.8{\mu}g/mL$, respectively, and the activity after fermentation was approximately 21.3% higher. These results indicated that fermented extract of P. tricuspidata stem has potentials as natural cosmetic ingredients with antioxidant and anti-wrinkle effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.238-243
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• 2002

The dielectric properties and synthesis of $LaAIO_3$ ceramics from mixtures of $La_2O_3$ and $AI(OH)_3$ via ground(planetary ball mill) and unground(wet ball mill) were investigated. The single phase $LaAIO_3$ of ground powder was formed at $1000^{\circ}C$, while that of unground powder was formed at $1300^{\circ}C$. Density and grains of ground sample showed 98% of theory density and a uniform size of 0.75\mu\textrm{m}$, respectively, However those of unground sample showed 93% and non-uniform sizes of 4-5 $\mu\textrm{m}$. Dielectric constant and temperature coefficient of capacitance ($\tau$c) of both ground and unground samples were 21~22 and +70~74 ppm$/^{\circ}C$, respectively. Dielectric loss of ground sample(0.0004) was 10 times as low as that of unground sample(0.003) due to a uniform and small gram size.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.391-400
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• 2015

In the present study, 50% ethanol extract, the ethyl acetate and aglycone fraction were prepared from mate (Ilex paraguariensis) and their antioxidative ability was evaluated. The yields of extract and fractions were 32.0, 4.48 and 0.82% per dried powder, respectively. Free radical scavenging activities were performed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and total antioxidant capacity was estimated using luminol-dependent chemiluminescence assay. Free radical scavenging activities ($FSC_{50}$) of 50 % ethanol extract, ethyl acetate fraction and aglycone fraction were 8.83, 5.84 and $6.05{\mu}g/mL$, respectively. Their total antioxidant capacities ($OSC_{50}$) were similar to that of L-ascorbic acid ($1.72{\mu}g/mL$), known as a prominent water soluble antioxidant, in all extracts and 50% ethanol extract ($1.03{\mu}g/mL$) was the most effective. The cellular protective effects on the $^1O_2$-induced cellular damage of erythrocytes were evaluated and the results showed that all extracts were significantly higher than (+)-${\alpha}$-tocopherol at $10{\mu}g/mL$. Especially, the ${\tau}_{50}$ value of aglycone fraction was 5 times higher than (+)-${\alpha}$-tocopherol at $10{\mu}g/mL$ and $50{\mu}g/mL$. The inhibitory effects of the ethyl acetate and aglycone fractions on tyrosinase were similar to arbutin, known as the whitening agent in cosmetics. These results suggest that the extracts of mate have the applicability as antioxidant and anti-aging cosmeceutical ingredients.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.1
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• pp.28-31
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• 2016

Purpose $^{223}Ra-Dichloride$ is used for the medicine of castration-resistant prostate cancer (CRPC) and which emits ${\alpha}-ray$ of 28 Mev that is used for therapy. However $^{223}Ra-Dichloride$ emits ${\beta}-ray$ of 3.6% and ${\gamma}-ray$ of 1.1%(80,156,270 keV) aside from ${\alpha}-ray$ in decay. Therefore we would like to evaluate external radiation expose dose rate of ${\gamma}-ray$ of $^{223}Ra-Dichloride$. Materials and Methods We calculated external radiation expose dose rate using ${\gamma}-constant$ of $^{223}Ra-Dichloride$, $^{99m}Tc$ based on Health physics(2012). $^{223}Ra-Dichloride$ of 3.5 MBq and $^{99m}Tc-MDP$ of 740 MBq were applied. external radiation expose dose rate 15 times from 1m by survey meter. Results ${\gamma}-contant$ of $^{223}Ra$, $^{99m}Tc-MDP$ from 1m distance based on Health physics(2012) is 0.0469, 0.0215. calculated value of external radiation expose dose rate was $16{\mu}Sy$, $34{\mu}Sy$ which activity is $^{223}Ra-Dichloride$ of 3.5 MBq and $^{99m}Tc-MDP$ of 740 MBq from 1 m and measured mean value of 1 m was $0.7{\mu}Sy/h$, $18{\mu}Sy/h$. Conclusion ${\gamma}-constant$ of $^{223}Ra$ is higher than $^{99m}Tc$ based on Health physics(2012). however calculated maximum external radiation expose dose rate of $^{223}Ra-Dichloride$ is lower than $^{99m}Tc$ due to actually used quantity of activity of $^{223}Ra-Dichloride$ is small. measured value of $^{223}Ra-Dichloride$ is also lower than $^{99m}Tc-MDP$. Therefore external radiation expose dose rate of ${\gamma}-ray$ of $^{223}Ra-Dichloride$ is very low.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.68-72
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• 2002

In this research, the effects of capacitance to the access time were studied at the junction area of tunneling magnetoresistance when these were used as memory devices. These results were obtained by applying electric signal input and magnetic field was not used. We applied bipolar square waves of 1MHz to the MTJ samples to obtain the results and time constant ($\tau$) calculated by observing wave responses utilizing an oscilloscope. And time constant was compared with junction area. Each part of MTJ sample, such as electrical pad, lead and contact area, was modeled as an electrical equivalent circuit based on experimental results. For the 200㎛$\times$200㎛ cell, junction capacitance was 90 pF. Also, measurement and simulation results were compared, which showed those similarity.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.479-484
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• 2017

In this study, antioxidative activities and cellular protective effects of 70% ethanol extracts and fractions from lavender were evaluated. The scavenging activity ($FSC_{50}$) of free radical (1,1-phenyl-2-picrylhydrazyl, DPPH) was 46.6, 45.5 and $477.5{\mu}g/mL$ in the 70% ethanol extract, ethyl acetate fraction and aglycone fraction, respectively. The reactive oxygen species scavenging activities (${OSC_{50}$) of 70% ethanol extract, ethyl acetate fraction and aglycone fraction were 8.1, 3.3 and $17.6{\mu}g/mL$, respectively, and they showed lower antioxidative activity than that of using L-ascorbic acid ($1.5{\mu}g/mL$). However, the aglycone fraction showed higher photohemolysis protective effect than that of using the 70% ethanol extract and ethyl acetate fraction. At $50{\mu}M$ concentration, the cellular protective effect (${\tau}_{50}$) of 70% ethanol extract, ethyl acetate fraction and aglycone fraction from lavender was 70.6, 87.2 and 165.2 min, respectively. In particular, the lavender aglycone fraction showed 3.8 times higher cellular protective effect than that of (+)-${\alpha}$-tocopherol. The lavender fractional components including luteolin 7-O-glucuronide, vitextin, rosmarinic acid, luteolin, and apigenin were identified using TLC and LC-MS. However, the lavender aglycone fraction did not show any significant increase in flavonoids (luteolin and apigenin) compared to that of the ethyl acetate fraction. In conclusion, it is suggested that lavender may be applied as an antioxidant material in cosmetic industries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.288-289
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• 2006

We studied the effect of sol-gel processing and sintering temperature on the microwave properties of $MgCo_2(VO_4)_2$ system(MCV) which is applicable to LTCC(low-temperature cofired ceramics). The MCV was synthesized by sol-gel process using solution that contains precursor molecules for Mg, Co, and V. SEM analysis shows that the average particle size is ${\sim}1{\mu}m$ and size distribution is very uniform compared to the one prepared by conventional solid-state reaction process. Highly dense samples were obtained at the sintering temperature range of $750^{\circ}C{\sim}930^{\circ}C$. The maximum $Q{\times}f_0$ value of 55,700GHz, dielectric constant(${\varepsilon}_r$) of 10.41 and temperature coefficient(${\tau}_f$) of $-85ppm/^{\circ}C$ was obtained at the sintering temperature of $930^{\circ}C$. The superior microwave properties of sol-gel processed MCV relative to conventional solid-state reaction processed one is remarkable especially at lower sintering temperatures such as $750^{\circ}C$ and $800^{\circ}C$.