• 동의생리병리학회지
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• 제16권2호
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• pp.348-352
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• 2002

This study was carried out to evaluate cytotoxic effects of Atractylodes macrocephala Koidz. (A. macrocephala Koidz.) extract on NIH 3T3 fibloblast. SK-MEL-3 (HBT 69) and KB (ATCC No, OCL 17) cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. 10.2 mg/ml Concentration of A. macrocephala Koidz. extracts in SK-MEL-3 showed that their susceptibility (sensitivity) to these compounds decreased in the following order ; adriamycin > H₂O > ethyl acetate > ethyl alcohol > chloroform > n-hexane in SK-MEL-3 cell lines ; 5-FU > H₂O > n-hexane > ethyl acetate > ethyl alcohol > chloroform in KB cell lines. In order to develop an antimicrobial agent, A. macrocephala Koidz. was extracted with solvents. The minimal inhibitory concentrations (MICs) of each solvent extract of A. macrocephala Koidz. against microogranisms were also examined. Antimicrobial activities of ampicillin and ketoconazole as references were compared to those of each solvent extract of A. macrocephala Koidz. The antimicrobial activity of the ethyl acetate soluble extract of A. macrocephala Koidz. had growth inhibition activity against S. mutans and P. putida (MICs. 500 ㎍/ml). These results suggest that the ethyl acetate soluble extract of A. macrocephala Koidz. possessed antitumorous and antimicrobial agents

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.357-358
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• 2005

Compact power amplifier modules (PAM) for WCDMA/KPCS and GSM/WCDMA dual-band applications based on multilayer low temperature co-fired ceramic (LTCC) substrates are presented in this paper. The proposed modules are composed of an InGaP/GaAs HBT PAs on top of the LTCC substrates and passive components such as RF chokes and capacitors which are embedded in the substrates. The overall size of the modules is less than 6mm $\times$ 6mm $\times$ 0.8mm. The measured result shows that the PAM delivers a power of 28 dBm with a power added efficiency (PAE) of more than 30 % at KPCS band. The adjacent-channel power ratio (ACPR) at 1.25-MHz and 2.25-MHz offset is -44dBc/30kHz and -60dBc/30kHz, respectively, at 28-dBm output power. Also, the PAM for WCDMA band exhibits an output power of 27 dBm and 32-dB gain at 1.95 GHz with a 3.4-V supply. The adjacent-channel leakage ratio (ACLR) at 5-MHz and 10-MHz offset is -37.5dBc/3.84MHz and -48dBc/3.84MHz, respectively. The measured result of the GSM PAM shows an output power of 33.4 dBm and a power gain of 30.4 dB at 900MHz with a 3.5V supply. The corresponding power added efficiency (PAE) is more than 52.6 %.

• 한국표면공학회지
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• 제54권1호
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• pp.1-11
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• 2021

Porous dendrite structure AuCu alloy was formed using a hydrogen bubble template (HBT) technique by electroplating to improve the catalytic performance of gold, known as an excellent oxygen reduction reaction (ORR) catalyst in alkaline medium. The rich Au surface was maximized by selectively electrochemical etching Cu on the AuCu dendrite surface well formed in a leaf shape. The catalytic activity is mainly due to the synergistic effect of Au and Cu existing on the surface and inside of the particle. Au helps desorption of OH- and Cu contributes to the activation of O2 molecule. Therefore, the porous AuCu dendrite alloy catalyst showed markedly improved catalytic activity compared to the monometallic system. The porous structure AuCu formed by the hydrogen bubble template was able to control the size of the pores according to the formation time and applied current. In addition, the Au-rich surface area increased by selectively removing Cu through electrochemical etching was measured using an electrochemical calculation method (ECSA). The results of this study suggest that the alloying of porous AuCu dendrites and selective Cu dissolution treatment induces an internal alloying effect and a large specific surface area to improve catalyst performance.