• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1235-1239
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• 2010

In this work, a wideband technique has been proposed that improves the IF bandwidth of mixers and a 24-GHz down-conversion mixer employing the proposed technique has been designed and fabricated based on 0.13-${\mu}m$ RFCMOS technology. The mixer showed the conversion gain of $2.7{\pm}1.5$ dB from DC to 5.25 GHz IF for a fixed LO frequency of 24 GHz. Measured P-1dB and LO-RF isolation was -8.7 dBm and 21 dB, respectively. The mixer draws DC current of 10.6 mA from 1.3 V supply.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.613-615
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• 2014

The design and implementation of a broadband and linear HPA(High Power Amplifier) for TVWS are presented in this paper. The spectrum mask and transmitted power of HPA for TVWS must be controlled and meet the regulations to minimize interference effects on present broadcasting systems. The implemented HPA has the operating frequency of 460 ~ 698MHz with $24.7{\pm}1dB$ gain, input reflection coefficient of below -25dB, output reflection coefficient of below -7.28dB and the linearity of -57.7dBc at 22.2dBm output power.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.205-210
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• 2018

This study was performed to investigate the effect of types of oil (OVOIL vs. OIL) on B6D2F1 mice oogenesis. In this study, B6D2F1 F1 mice were used in order to maximize oogenesis. The expansion rate of cumulus cells ($82.0%{\pm}0.2$ vs. $78.0%{\pm}0.1$), in vitro fertilization rate ($92.0%{\pm}0.1$ vs. $88.0%{\pm}0.1$), developmental rate ($91.0%{\pm}0.1$ vs. $87.0%{\pm}0.2$), blastocysts formation rate ($56.0%{\pm}0.1$ vs. $57.0%{\pm}0.1$), and zona hatched rate($41.4%{\pm}0.2$ vs. $24.0%{\pm}0.1$) were not different between groups (NS; P>0.05). However, there was a significant difference in maturation rate; the OVOIL group showed higher maturation rate compared to that of the OIL group ($96.0%{\pm}0.1$ vs. $87.0%{\pm}0.1$; P<0.05). In the blastocysts cell numbers, the total cell numbers ($83.9{\pm}26.1$ vs. $56.9{\pm}23.9$), ICM cell numbers ($15.7{\pm}8.8$ vs. $6.3{\pm}3.5$), TE cell numbers ($68.3{\pm}25.7$ vs. $50.7{\pm}24.1$), % ICM ($21.6%{\pm}0.1$ vs. $12.7%{\pm}0.1$), and the ratio of ICM:TE ($1:6.2{\pm}6.5$ vs. $1:10.3{\pm}7.0$) were significantly higher in the OVOIL group than the OIL group (P<0.05). These results suggested that it is expected to achieve the more developmental ability of B6D2F1 mice depending on the type of oil (OVOIL vs. OIL). In addition, the results can provide essential information for culture condition on B6D2F1 mice. Henceforth, thus, it is expected that these results herein might be used for in vitro culture of human embryos.

• Journal of Embryo Transfer
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• v.31 no.1
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• pp.19-25
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• 2016

This study was conducted to evaluate the effects of type of culture media (BM, G2, OS, TCM, and MEM) on B6D2F1 mice oogenesis. In the present study, B6D2F1/CrljOri $F_1$ mice were utilized in order to maximize oogenesis. Also we used TCM-199, Dulbecco's medified Eagle's medium (DMEM), embryo culture medium (Fertilization medium, Cleavage medium, Blastocyst medium), G series medium and One step medium. In vitro maturation was highest in BM followed by the order of OS, MEM, TCM and G2 ($90{\pm}2.8%>88{\pm}3.2%>85{\pm}4.9%>78{\pm}10.2%>64{\pm}7.7%$, respectively). To note, the G2 group was statistically different compared to other groups (p<0.05). On the other hand the fertilization rate was highest in the G2 group followed by BM, OS, TCM, and MEM ($87{\pm}7.2%>85{\pm}6.9%>74{\pm}14.0%>71{\pm}13.8%>2{\pm}1.4%$, respectively). The MEM group was significantly lower compared to other groups (p<0.05). The developmental rate was highest in the OS group followed by the G2 group and the BM group albeit no statistical significance was noted ($73{\pm}11.6%>71{\pm}9.2%>66{\pm}10.4%$). Of note, all cells of the TCM and MEM groups were died during embryonic development. The zona hatched rate ($51{\pm}9.8%$ vs. $50{\pm}9.1%$ vs. $47{\pm}7.2%$ for BM, G2, and OS respectively) and attached rate ($45{\pm}12.3%$ vs. $38{\pm}16.1%$ vs. $37{\pm}11.5%$ for BM, G2, and OS respectively) were not different amongst groups. No difference was found in total cell numbers ($74{\pm}13.9$ vs. $64{\pm}9.2$ vs. $76{\pm}6.7$ for BM, G2, and OS respectively), ICM cell numbers ($20{\pm}1.9$ vs. $14{\pm}1.8$ vs. $15{\pm}2.1$), TE cell numbers ($55{\pm}12.5$ vs. $49{\pm}10.7$ vs. $61{\pm}5.9$), % ICM ($30{\pm}2.8%$ vs. $24{\pm}7.0%$ vs. $22.8{\pm}2.2%$) and ICM:TE ratio ($1:2{\pm}0.5$ vs. $1:3.1{\pm}0.8$ vs. $1:3.1{\pm}0.5$) amongst groups. In summary, these results can provide fundamental data to maximize culture condition for in vitro fertilization on B6D2F1 mice.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.243-250
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• 2009

To develop a new natural whitening agent for cosmetics, we investigated the inhibitory effects of Poria cocos Bark extracts (PCBE) and its active compound on melanogenesis. PCBE showed ROS scavenging activities in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and xanthine/xanthine oxidase system with the $IC_{50}$ values of $19.4{\pm}2.21{\mu}g$/mL and $IC_{50}=103{\pm}3.33{\mu}g$/mL, respectively. PCBE reduced intracellular tyrosinase activity about 34 % at concentration of $50{\mu}g$/mL. And PCBE reduced melanin contents of B16 melanoma cells about 51 % at concentration of $50{\mu}g$/mL without cell cytotoxicity (below $100{\mu}g$/mL). We purified one active compound from PCBE and identified its structure. It was identified as 3-$\beta$-hydroxylanosta-7,9(11),24-trien-4-oic acid, triterpene family, by $^1H$-NMR, $^{13}C$-NMR and Mass analysis. 3-$\beta$-hydroxylanosta-7,9(11),24-trien-4-oic acid showed ROS scavenging activities in DPPH radical and xanthine/xanthine oxidase system with the $IC_{50}$ values of $4.3{\pm}0.15{\mu}g$/mL and $54{\pm}1.67{\mu}g$/mL, respectively. Also, it was shown that 3-$\beta$-hydroxylanosta-7,9(11),24-trien-4-oic acid reduced intracellular tyrosinase activity about 43 % at concentration of $10{\mu}g$/mL. And it inhibited melanin synthesis in a dose dependent manner ($IC_{50}=3.6{\mu}g$/mL) without cell cytotoxicity (below $100{\mu}g$/mL). 3-$\beta$-hydroxylanosta-7,9(11),24-trien-4-oic acid inhibited tyrosinase, TRP-1 and TRP-2 expression at protein level. These results suggest that PCBE and 3-$\beta$-hydroxylanosta-7,9(11),24-trien-4-oic acid reduced melanin formation by the inhibition of tyrosinase activity and expression in B16 melanoma cells. Therefore, we suggest that PCBE could be used as a useful whitening agent.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.825-832
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• 2011

In this paper, we described the design and measurement results of a Front-End Receiver for S-band active phased array radar. The Front-End Receiver has input P1dB of -4dBm and IIP3 of 7dBm. The measurement results show that gain is $24{\pm}0.7dB$, noise figure are less than 2.3dB over the frequency range of $fc{\pm}0.2GHz$. The Front-End Receiver can protect the receiver path from large input signals with a maximum peak power of multi-kW and recovery time is less than 0.8us. The measurement results satisfy all specifications.

• Journal of Aquaculture
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• v.1 no.1
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• pp.13-24
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• 1988

In order to investigate a reasonable rearing density and the possibility of high-density rearing, flounder, Paralichthys olivaceus, juveniles of 2.53$\pm$0.24 cm in total length and 1.12$\pm$0.12 cm in body height were used in this study. The initial rearing density of them was 10 (D10), 20 (D20), 30 (D30) and 40 (D40) individuals per 137.75 $cm^2$ of bottom area, respectively. Ranges of water temperature and specific gravity during the rearing period of 65 days were $21.0\~27.0^{\circ}C$ and 1.024$\~$1.026, respectively, showing relatively higher values than that of natural sea water. Dissolved oxygen during the rearing period was 5.4$\~$7.5 ml/$\iota$ and inorganic nitrate was 0.07$\~$0.48 ppm in $NH_4^+-N$, 0.006$\~$0.33 ppm in $NO_2^{-}-N$ and 3.89$\~$34.06 ppm in $NO_3^{-}-N$. Growth in total length and body height of the juveniles in four rearing density at the end of the experiment was 8.17$\pm$0.80 em and 4.16$\pm$0.39 em, the highest in D20 and 7.72$\pm$0.40 cm and 3.94$\pm$0.21 cm, the lowest in D10. Significant differences, however, were not recognized between the slope values of growth regressions in four rearing density. Slope values of the relative growth between total length and body height of the juveniles in four rearing density were 0.5346, the highest in D10 and 0.5165, the lowest in D30, but there were no significant differences in those values. Survival rate of juveniles at the end of the experiment was $90\%$ in D10, D20 and D30, but that of D40 was $75\%$. The relationship between total length X body height (X) and body surface area of ocular side (Y) to calculate the rate of Y to bottom area in rearing tank (covering rate) as an indicator of rearing density was expressed by a linear regression, Y=0.5994X+0.1840. Covering rate in four rearing density at the end of the experiment was ranged 1.2$\~$4.1 times. Judging from the covering rate above 4 times, it seems to be possible rearing the flounder juveniles in high-density.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.67-76
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• 2016

This study was conducted to examine the optimal environmental condition for promoting the growth of sowthistle as affected by light quality and photoperiod in a closed-type plant production system. Seeds were sown in 240-cell plug trays and then germinated for 3 days at a 24-hour photoperiod in a closed-type plant production system with LED lights (R:B:W = 8:1:1). Seedlings were transplanted and grown under 3 types of LED (R:B:W = 8:1:1, R:W = 3:7, or R:B = 8:2) and 4 photoperiods (24/0, 16/8, 8/16, or 4/20 hours) with $230{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ light intensity at a density of $20cm{\times}20 cm$. The experimental design was a randomized complete block design. Plants were cultured for 40 days un der the condition of $21{\pm}2^{\circ}C$ and $70{\pm}10%$ relative humidity after transplanting. Plants were fed with a recycling nutrient solution (pH 7.0 and EC $2.0dS{\cdot}m^{-1}$) contained in a deep floating tank. Fresh weight and dry weight of shoot or root, leaf length, and leaf area were the greatest in the photoperiod of 24/0 (light/dark) with RW LED. The highest number of leaves occurred in the photoperiod of 16/8 (light/dark) with RB LED, while the incidence of tip burn was higher in the photoperiod of 24/0 (light/dark) compared to the other treatments. Chlorophyll value was the highest in the 16/8 (light/dark) photoperiod and there was no significant difference by light quality. Chlorophyll fluorescence was the lowest in the photoperiod of 24/0 (light/dark) compared with other treatments. Therefore, in terms of economic feasibility and productivity for Ixeris dentata Nakai cultivation in a closed-type plant production system, the results obtained suggest that plants grew the best when kept in a photoperiod of 16/8 (light/dark) and light quality of combined LED RW (3:7).

• Journal of Embryo Transfer
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• v.31 no.4
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• pp.367-374
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• 2016

This study was conducted to evaluate the effect of transfer temperature of epididymis on survival rate of semen and development ability of B6D2F1 mice embryos. No significant differences were noted in the survival rate of semen ($59.0%{\pm}0.1$ vs. $47.6%{\pm}0.1$), in vitro fertilization rate ($90.7%{\pm}0.1$ vs. $90.7%{\pm}0.1$), developmental rate ($90.0%{\pm}0.1$ vs. $90.0%{\pm}0.1$), and blastocysts formation rate ($53.1%{\pm}0.2$ vs. $52.3%{\pm}0.2$) between groups. (NS; P>0.05). However, the zona hatched rate was significantly higher in the $4^{\circ}C$ group compared to those of the $37^{\circ}C$ group ($47.8%{\pm}0.1$ vs. $25.6%{\pm}0.2$; p<0.05). When it comes to cell numbers of blastocysts, the % ICM (/total cells) was significantly higher in the group of $4^{\circ}C$ compared to the $37^{\circ}C$ ($27.0%{\pm}0.1$ vs. $18.3%{\pm}0.1$; p<0.05). However there were no differences in total cell numbers ($72.7{\pm}31.6$ vs. $62.0{\pm}36.6$), ICM cell numbers ($17.0{\pm}7.8$ vs. $14.6{\pm}8.6$), TE cell numbers ($55.8{\pm}29.8$ vs. $64.0{\pm}24.4$), the ratio of ICM:TE ($1:4.2{\pm}4.1$ vs. $1:6.4{\pm}7.2$) between two groups (NS; P>0.05). Taken altogether, it is expected to achieve the best developmental ability of B6D2F1 mice embryos in the transfer temperature of epididymis. Also these results can provide fundamental data to maximize culture condition for in vitro fertilization on B6D2F1 mice. In future, therefore, it is expected that results herein might be applied for in vitro culture of human embryos.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.273-278
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• 2016

Responded threshold level in hearing screening depends on the noise level of test surroundings, physiological characteristics of hearing organs, excessive sound source exposures, and so on. The purpose of this study is to obtain the basic information of hearing threshold level at each frequencies in children with passed hearing screening. Subjects were 110 children, aged were from 3.3 to 16.3 ($9.01{\pm}2.52$), who were at private speech language pathological clinics and daycare centers. Methods of Hearing screening were tympanometry, acoustic reflex threshold, automated otoacoustic emission, and pure tone screening. The subjects were in normal criteria of hearing screening. The differences of hearing threshold among ages and frequencies were measured by means of repeated measures ANOVA. The mean of hearing thresholds level was observed $16{\pm}6.49$, $11.5{\pm}4.79$, $6.86{\pm}4.99$, $5.95{\pm}6.65$ dB HL in the right ear and $15.68{\pm}6.01$, $9.95{\pm}5.24$, $5.72{\pm}5.21$, $5.63{\pm}7.04$ dB HL in the left ear, in frequency of 500, 1,000, 2,000, 4,000 Hz respectively. There was a significant difference between 500 and 1,000, 2,000, 4,000 Hz (p=.000), between 1,000 and 2,000, 4,000 Hz (p=.000).