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총고조파 왜율과 리플 감쇄율을 이용한 계통연계형 PCS용 LCL 필터 설계 (LCL Filter Design for Grid-connected PCS Using Total Harmonic Distortion and Ripple Attenuation Factor)

박종형;지민훈;김흥근;전태원;노의철
- 전력전자학회논문지
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- 제15권3호
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- pp.235-243
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- 2010
본 논문에서는 총고조파 왜율(THD, Total Harmonic Distortion)과 리플 감쇄율(RAF, Ripple Attenuation Factor)을 이용한 계통연계 인버터용 LCL 필터 설계 방법을 제안한다. 인버터 측 인덕터 전류의 총고조파 왜율($THD_i$)과 필터 커패시터와 계통 측 인덕터 사이의 전류 리플 감쇄율(RAF), 그리고 계통에 주입되는 전류의 총고조파 왜율($THD_g$)의 관계를 분석하여 관계식을 도출하고, 이 관계식을 바탕으로 계통 주입 전류의 $THD_g$ 목표치를 만족하는 $THD_i$와 RAF를 선정하여 계통 측 인덕터($L_g$)와 인버터 측 인덕터($L_i$)의 인덕턴스 값을 계산한다. 한편 커패시터의 커패시턴스 값은 커패시터에 유입되는 무효전력을 고려하여 선정한다. 제안한 방법으로 LCL를 설계하여 시뮬레이션과 실험을 통해 계통에 주입되는 전류의 $THD_g$가 목표치를 만족하는 것을 보임으로써 설계 방법의 타당성을 입증한다.
https://doi.org/10.6113/TKPE.2010.15.3.235 인용 PDF KSCI

Antioxidant Activity of Glycyrrhiza cultivar Extracts

Kim, Minhee;Kang, Myunghoon;Kim, Wonnam
- 한국자원식물학회:학술대회논문집
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- 한국자원식물학회 2019년도 추계학술대회
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- pp.88-88
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- 2019
Antioxidants are involved in the defense mechanism against the attack of free radicals. This study was carried out to determine the antioxidant activity of new variety of Glycyrrhiza cultivar radix, Wongam and Sinwongam. Dissolved freeze dried Wongam and Sinwongam extracts were filtered by $0.2{\mu}m$ filter and serially diluted at the concentrations of $10{\mu}g/mL$, $50{\mu}g/mL$, $100{\mu}g/mL$, $500{\mu}g/mL$, and $1000{\mu}g/mL$. The antioxidant potential was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, ABTS (2,2-azino-bis (3-rthylbenzthiazoline-6-sulfonic acid) diammonium salt) radical cation decolorization assay, nitrite radical scavenging assay, and ferric reducing antioxidant power (FRAP) assay. DPPH radical scavenging activities (i.e. the highest value $50.9{\pm}0.8%$ by Wongam and $82.6{\pm}1.1%$ by Sinwongam), ABTS radical scavenging activities (i.e. the highest value $88.1{\pm}1.8%$ by Wongam and $98.6{\pm}0.1%$ by Sinwongam), and nitrite radical scavenging activities (i.e. the highest value $87.3{\pm}1.6%$ by Wongam and $89.8{\pm}0.8%$ by Sinwongam) increased in a dose-dependent manner. In addition, ferric reducing power activities also increased in a dose-dependent manner. The FRAP value of Wongam and Sinwongam extracts were $0.72{\pm}0.03$ and $0.99{\pm}0.06$ compared to ascorbic acid, as a positive control, was $1.32{\pm}0.02$. These results suggested that Wongam and Sinwongam have beneficial effects as a potent antioxidant.
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Impact of axial power distribution on thermal-hydraulic characteristics for thermionic reactor

Dai, Zhiwen;Wang, Chenglong;Zhang, Dalin;Tian, Wenxi;Qiu, Suizheng;Su, G.H.
- Nuclear Engineering and Technology
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- 제53권12호
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- pp.3910-3917
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- 2021
Reactor fuel's power distribution plays a vital role in designing the new generation thermionic Space Reactor Power Systems (SRPS). In this paper, the 1/12th SPACE-R's full reactor core was numerically analyzed with two kinds of different axial power distribution, to identify their impacts on thermal-hydraulic and thermoelectric characteristics. In the benchmark study, the maximum error between numerical results and existing data or design values ranged from 0.2 to 2.2%. Four main conclusions were obtained in the numerical analysis: a) The axial power distribution has less impact on coolant temperature. b) Axial power distribution influenced the emitter temperature distribution a lot, when the core power was cosine distributed, the maximum temperature of the emitter was 194 K higher than that of the uniform power distribution. c) Comparing to the cosine axial power distribution, the uniform axial power distribution would make the maximum temperature in each component of the reactor core much lower, reducing the requirements for core fuel material. d) Voltage and current distribution were similar to the axial electrode temperature distribution, and the axial power distribution has little effect on the output power.
https://doi.org/10.1016/j.net.2021.06.035 인용 PDF KSCI