• 한국균학회지
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• 제51권1호
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• pp.39-49
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• 2023

남덕유산 월성계곡과 대전광역시 진참천 등지로부터 분리한 야생효모들 중 국내 미기록 야생효모들을선별한후, 이들의균학적특성과효소활성및생리활성등을조사하였다. 이들야생효모들중Candida sorboxylosa WSC25-4 (NNIBRFG47336), Arxula adeninivorans WSC6-3 (NNIBRFG47335), Farysizyma taiwaniana JRC6-2 (NNIBRFG47339), Saturnispora dispora JTS19-1 (NNIBRFG47334), Vanderwaltozyma polyspora JJCH5-3 (NNIBRFG47337)과Vanrija fragicola SW-9 (NNIBRFG47338) 등 6균주들을 국내 미기록 야생효모들로 최종 선별하였다. 이들 균주들은 대부분 구형으로 출아에 의해 영양증식을 하였고, 모두 자낭포자와 의균사들을 형성하지 않았다. V. polyspora JJCH5-3외 5균주들이 YPD, YM, PD등의 배지에서 잘 생육하였고, A. adeninivorans WSC6-3와S. dispora JTS19-1 균주들은 40% 포도당을함유한 YPD 배지에서잘생육하는내당성을보였으며, V. fragicola SW-9 균주는 5% NaCl을 함유한 YPD배지에서 생육하는 호염성 효모로 확인되었다. 국내 미기록 야생효모들의 배양 상등액들 중A. adeninivorans WSC6-3과F. taiwaniana JRC6-2, V. fragicola SW-9 등의 glucoamylase 활성이 각각 58.0, 59.0, 59.0% 로 비교적 높았고, C. sorboxylosa WSC25-4 균주는 알칼리성 단백질분해효소 활성이 높아 세재 산업에 유용할 것으로 사료된다. 또한, 미기록 효모들의 모든배양상등액은항산화활성과 SOD-유사활성이 70-98%로매우높았고, S. dispora JTS19-1과V. fragicola SW-9의항통풍성잔틴산화효소저해활성도각각 70%와 80%로높았다.

• 분석과학
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• 제5권4호
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• pp.417-423
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• 1992

음극 벗김 전압전류법을 이용하여 비소(III)의 벗김 봉우리에 대한 금속 이온의 영향에 대하여 조사하였다. 비소(III)의 환원 벗김 봉우리 이론적인 전위값이 -0.84V(vs. Ag/AgCl)인데 비하여, 0.1N- 염산을 사용하였을 때 전위값은 -0.79V(vs. Ag/AgCl)이고, 여기에 구리(II)를 10배 첨가하였을 때 -0.84V로써 이론적인 전위값과 일치하였으며 전류값은 $0.86{\mu}A$로 가장 높게 나타났다. 비소(III)의 벗김 봉우리를 증가시키는 금속이온으로 납(II), 구리(II) 등이 있었고, 특히 구리(II)이온이 비소(III)의 벗김 봉우리를 가장 많이 증가시켰다.

• 한국자원식물학회지
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• 제4권1호
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• pp.17-22
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• 1991

Codonopsis lanceolata and C.pilosula medicinal plants were subjected to preliminary antitumor screening test with Sarcoma 180 ascites and screning on V-79 cell. This ex-periments Iwere conducted in accordance with the Total packed cell Volume methodand Cytotoxicity method .

• 한국가축번식학회지
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• 제21권2호
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• pp.177-183
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• 1997

The present study examined the effects of epidermal growth factor(EGF) and transforming growth factor-$\alpha$(TGF-$\alpha$) on in vitro maturation of porcine follicular oocytes. Basic medium used TCM-HEPES, and oocytes cultured for 42 hours in vitro. The results obtained are as follows; 1. The nuclear maturation rates of EGF-treated groups(10ng/ml, 75.9% ; 30ng/ml, 69.2% ; 50ng/ml, 67.2% ; 100ng/ml, 71.0%) on the porcine oocytes cultured in medium without pFF in vitro were significantly(P<0.01) higher than those of non-treated group(57.1%). When the oocytes were cultured in media with 10%(v/v) pFF, the nuclear maturation rates of 30ng EGF/ml(77.1%) treated group were significantly(P<0.01) higher than those of non-(59.2%) and EGF-treated groups(10ng/ml, 65.4% ; 50ng/ml, 65.5% ; 100ng/ml, 70.4%). 2. The nuclear maturation rates of 30ng TGF-$\alpha$/ml treated group(71.9%) in media without pFF in vitro were significatnly(P<0.01) higher than those of non-(57.1%) and TGF-$\alpha$ treated groups(10ng/ml, 60.4% ; 50ng/ml, 65.4% ; 100ng/ml, 60.0%). When the oocytes were cultured in media with 10%(v/v) pFF, the nuclear maturation rates of 30 and 50ng TGF-$\alpha$/ml(77.4% and 79.6%) treated groups(10ng/ml, 64.2% ; 100ng/ml, 61.6%). 3. On the effect of EGF(30ng/ml) and/or TGF-$\alpha$(30ng/ml) treated groups in medium without pFF in vitro, the nuclear maturation rates indicated 57.3, 60.4, 75.9 and 79.7% in media with no EGF & TFG-$\alpha$, TGF-$\alpha$ only, EGF only nad EGF＋TGF-$\alpha$ treated groups, respectively. The nuclear maturation rates in medium with EGF only or EGF＋TGF-$\alpha$ were significantly(P<0.01) higher than those non- and TGF-$\alpha$ treated groups. When the oocytes were cultured in media with 10%(v/v) pFF, the nuclear maturation ratesof EGF＋TGF-$\alpha$ treated group(75.9%) were significantly(P<0.01) higher than those of non-(59.2%), TGF-$\alpha$ only (64.2%) and EGF only(69.4%) treated groups.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.427-434
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• 2006

This paper analyzes arc phenomena including the secondary arc's elongation in the Korean 765kV single transmission line (79km) between Sin-Ansung S/S and Sin-Gapyeong S/S, which will be installed in Korea in June 2006. In particular, both frequency independent and frequency dependent line models are compared to make our final decisions. As well, the significant simulation results are investigated by the EMTP program. As a result, there is no need of HSGS in the Korean 765kV single transmission line from both a practical and an economical point of view.

• 한국통신학회논문지
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• 제40권9호
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• pp.1693-1698
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• 2015

본 논문은 이중 펄스 폭을 지닌 PFM(Pulse-Frequency Modulator) 부스트 변환기를 제안한다. 부스트 변환기의 구동 회로 구조는 밴드 갭 기준 전압 발생 회로와 이를 이용해 여러 가지의 기준 전압을 생성하는 기준 전압 발생 회로, 소프트 시동 회로, 에러 증폭기, 고속 전압 비교기, 인덕터 전류 센싱 회로, 펄스 폭 발생 회로로 구성되어있다. 변환기는 부하 전류 상태에 따라 서로 다른 최대 인덕터 전류 값을 갖도록 구성해 부하 범위를 넓히고, 출력 전압 리플을 감소하도록 했다. 제안된 PFM 부스트 변환기는 입력 전압으로 3.7V를 받고, 18V의 출력 전압을 생성한다. 구동 가능한 부하 전류는 0.1~300mA의 범위를 가진다. 모의실험 결과 저 부하 전류 동작 구간에서 0.43%, 고 부하 전류 동작 구간에서는 0.79%의 출력 전압 리플을 보였다. 변환기는 저 부하 구간에서 85%의 효율을 나타내며 20mA에서 86.4%로 최대의 효율을 나타냈다.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.195-199
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• 2000

Tyrosinase inhibitory activities of 14 kinds of seaweed, Ecklonia stolonifera, Ecklonia cava, Undaria pinnatiflda, Laminaria japonica, Sargassum fulvellum, Sargassum miyabei, Sargassum thunbergii, Porphyra yezoensis, Gracilaria verrucosa, Carpopeltis affinis, Pachymeniopsis elliptica, Gelidium amansii, Codium fragile and Ulva pertusa were determined using commercially available mushroom tyrosinase in an in vitro assay system. The $1\%$ (w/v) methanol extract from E. stolonifera showed the highest tyrosinase inhibitory activity of $79.0\%$, electron donating activity of $79.0\%$ and total phenol content of 3.75 mg/100g. Ethyl acetate-methanol-water (7 : 2 : 0.2, v/v) fraction $(0.5\%,\;w/v)$ isolated from the methanol extract showed tyrosinase inhibitory activity of $75.9 \%$, electron donating activity of $88.1 \%$ and total phenol content of 4.38 mg/100g. Tyrosinase inhibitory activity was closely associated with total phenol content (R = 0.99) and electron donating activity (R=0.99). Maximum absorption wavelength of the fraction was 218nm and that of phenolic compounds showed about a range from 210 to 220nm. The inhibition mode of the fraction was noncompetitive inhibition.

• 한국정보통신학회논문지
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• 제12권4호
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• pp.691-698
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• 2008

본 논문은 상위 7-비트와 하위3-비트의 binary-thermal decoding 방식과 segmented 전류원 구조로서 전력소모, 선형성 및 글리치 에너지 등 주요 사양을 고려하여, 3.3V 10비트 CMOS D/A 변환기를 제안한다. 동적 성능을 향상 시키기위해 출력단에 return-to-zero 회로를 사용하였고, segmented 전류원 구조와 최적화 된 binary-thermal decoding 방식으로 D/A 변환기가 가질 수 있는 장점은 디코딩 논리 회로의 복잡성을 단순화함으로 칩면적을 줄일 수 있다. 제안된 변환기는 $0.35{\mu}m$ CMOS n-well 표준공정을 이용한다. 설계된 회로의 상승/하강시간, 정착시간, 및 INL/DNL은 각각 1.90/2.0ns, 12.79ns, ${\pm}2.5/{\pm}0.7\;LSB$로 나타난다. 또한 설계된 D/A 변환기는 3.3V의 공급전원에서는 250mW의 전력소모가 측정된다.

• 열처리공학회지
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• 제18권3호
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• pp.183-189
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• 2005

The effects of duplex-treatment of plasma carburization and CrN coating onto Ti-6Al-4V alloy on its creep properties were investigated by means of a constant stress creep tester. Applying duplex-treatment, specimens having an inner carburized layer of about $150{\mu}m$ in depth and outer CrN layer of about $7.5{\mu}m$ in thickness were prepared. The hardness of duplex-treatment surface was about 1,960 VHN. It also appeared that the duplex-treatment improved the roughness of the surface significantly; $Ra=0.045{\mu}m$ for treated alloy while $Ra=0.321{\mu}m$ for untreated alloy. The steady-state creep behaviors were investigated in a temperature range of $510{\sim}550^{\circ}C$ ($0.42{\sim}0.44T_m$) under an applied stress range of 200~275 MPa. The stress exponent, n, was derived assuming the power law creep behavior. The surface treatment showed a decrease in a value from 9.32 (untreated) to 8.79 (treated). Also the activation energy obtained from an Arrhenius plot increased from 238 to 257 kJ/mol.

• Natural Product Sciences
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• 제13권2호
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• pp.118-122
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• 2007

We have studied the cytoprotective effect on H$_2$O$_2$ induced oxidative stress from leaves of Carpinus tschonoskii. The methanol extract of Carpinus tschonoskii was found to scavenge intracellular reactive oxygen species (ROS) using flow cytometry and confocal microscope. This extract prevented lipid peroxidation and thus reduced cell death of Chinese hamster lung fibroblast (V79-4) induced by H$_2$O$_2$ treatment. The extract increased catalase activity and phosphorylation of extracellular signal regulated kinase (ERK). Taken together, the results suggest that Carpinus tschonoskii protects V79-4 cells against oxidative damage by H$_2$O$_2$ through scavenging ROS.