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가정용 ESS를 위한 고효율 공진형 양방향 DC-DC 컨버터 개발 (Development of High Efficiency Bi-directional Resonant DC-DC Converter for Residential ESS)

  • 박준성;오세철;이상혁;김민재;박찬수;한국인;최세완
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 추계학술대회
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    • pp.191-192
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    • 2011

  • 본 논문에서는 가정용 ESS를 위한 직렬 공진형 양방향 DC-DC 컨버터를 제안한다. 제안한 컨버터는 2단 방식으로 비절연 컨버터가 전압 전류 및 양방향 제어를 하며 절연부는 고정듀티와 고정주파수로 동작시켜 전 부하영역에서 ZCS 턴온 턴오프가 가능하다. 50kHz, 3kW 시작품으로 제안한 방식의 타당성을 검증하였으며 강압시 최대효율 95.2 %, 승압시 최대효율 94.8%를 달성하였다.

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Changes of Ascorbic Acid and Nitrate Content in Lettuce by Unbalanced Nutrient Solution

  • Park, Yang-Ho;Park, So-Hyeon;Park, Jae-Hong;Lee, Ju-Young;Jang, Byoung-Choon;Lee, Ki-Sang
    • 한국작물학회지
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    • 제51권1호
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    • pp.107-111
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    • 2006

  • This study was to verity that the uptake inhibition and accumulation of nitrogen in different potassium levels. Lettuce was used as model plant in this study and grown in pot of 10cm's in diameter and depth with mixture media of vermiculite and perlite under supply of different culture solution for three weeks. Nitrogen absorption at root was inhibited by increased potassium concentration in nutrient solution, and nitrate accumulation of plant was depended on absorption of nitrogen because nitrate content of 0 K level was 4-5 times higher than that of 2 K level, Concentration of ascorbic acid was decreased by increasing the nitrogen absorption, since ascorbic acid (AsA) content of 2K level was higher than those of OK level in both of old leaf and flesh leaf.

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Isolation and Characterization of Antimicrobial Substance Macrolactin A Produced from Bacillus amyloliquefaciens CHO104 Isolated from Soil

  • Lee, Seung-Je;Cho, Jeong-Yong;Cho, Jung-Il;Moon, Jae-Hak;Park, Ki-Deok;Lee, Young-Ju;Park, Keun-Hyung
    • Journal of Microbiology and Biotechnology
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    • 제14권3호
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    • pp.525-531
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    • 2004

  • A strain antagonistic to Fusarium solani, CHO104, was selected from approximately 100 microorganisms isolated from soil. Strain CHO104 was identified as Bacillus amyloliquefaciens and found to be Gram-positive based on the Biolog system and 16S rRNA methods. A culture broth of B. amyloliquefaciens CHO104 also exhibited antimicrobial activity against various microorganisms. As such, the EtOAc extract of the culture broth was isolated by various column chromatographic procedures and HPLC. The antimicrobial and antifungal substance was then characterized as macrolactin A $(C_{24}H_{34}O_5)$ using high-resolution EI-MS and NMR analyses, and found to be very effective in inhibiting the growth of Staphylococcus aureus, E. coli, and Botrytis cinerea, even when using a concentration of one-twentieth of the benzoic acid as the control compound.

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