• 제목/요약/키워드: new shoot

검색결과 251건 처리시간 0.025초

Development of Multi-Cell Active Switched- Capacitor and Switched-Inductor Z-Source Inverter Topologies

  • Ho, Anh-Vu;Chun, Tae-Won;Kim, Heung-Geun
    • Journal of Power Electronics
    • /
    • 제14권5호
    • /
    • pp.834-841
    • /
    • 2014
  • This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.

Enhancement of In Vitro Regeneration of Several Ocimum Species and Varieties

  • Park Chung-Heon;Phippen Winthrop B.;Simon James E.;NamKoong Seung-Bak;Seong Nak-Sul
    • Plant Resources
    • /
    • 제8권3호
    • /
    • pp.275-280
    • /
    • 2005
  • Tissue culture systems to optimize regeneration plant species of Ocimum spp were evaluated as a method to micropropagate individual plants and to better study their biology in vitro. Ocimum species were also evaluated for the production of natural plant products during and following the regeneration process. The primary goal of this project was to enhance the regeneration efficiency of basil. Several factors were examined using different Ocimum species and commercial varieties. The effect of cytokinin combination, activated charcoal, gelling agents, and different carbon sources were investigated. Anthocyanin callus spots were produced only in four varieties among six tested. 'Sweet Dani' showed the best results on anthocyanin accumulation, while 'African beauty', 'Tree basil' and 'Methylcinnamate' produced only a few spots. Shoot regeneration was only achieved from 'Sweet Dani' explants. As the activated charcoal concentration increased, callus formation rate decreased respectively compare to the controls for all varieties. There was a decrease in callus growth with increasing concentration of agar and phytagel.

  • PDF

Plant Regeneration through Callus of Korean Native Seosanjong of Zingiber officinale Rosc.

  • Jo, Man-Hyun;Ham, In-Ki;Song, Nam-Hyun;Woo, In-Shik
    • Plant Resources
    • /
    • 제3권2호
    • /
    • pp.131-134
    • /
    • 2000
  • Embryogenic callus cultures of Korean native Seosanjong of ginger(Zingiber of officinale Rosc.) were induced through stem explants taken from in vitro shoot-tip cultures. Among the four concentrations of 2,4-D tested in Murashige and Skoog medium, 0.5 and 1 mg/L of 2,4-D was most effective in inducing embryogenic callus. Leaf explants did not express any new morphogenetic response in all 2,4-D concentrations tested. Plantlets transferred to hormone-free MS medium were developed and successfully acclimatized under greenhouse.

  • PDF

PWM 인버터의 전류파형 개선에 관한 연구 (Current Waveform Improvement of PWM Inverter)

  • 장석주;조상환;설승기
    • 대한전기학회논문지
    • /
    • 제39권3호
    • /
    • pp.273-280
    • /
    • 1990
  • To prevent the shoot-through phenomena in a PWM inverter, a short dead time is usually provided between a pair of switching transistors in the same leg of the inverter. In this approach, the amount of the dead time is designed to meet the worst case condition of the inverter transistors and the base drive elements. So, in normal cases, relatively large portion of the dead time is unnecessary and it results in an undesirablecurrent waveform distortion and generates ripple torque on the motor shaft. In this paper, a new base drive method to remove the undesirable portion of the dead time is described. The method senses the transistor on/off states to interlock the other transistor of the leg without the external dead time. Also, for the transistors of large current rating, the Darlington drive circuit is combined to the proposed method and is tested to verify the effectiveness. The experimental results of the proposed method are described and compared with those of the conventional dead time method.

압축공기의 흡입과 분사를 위한 멀티 에어건의 설계 개발 (A Design and Development of Multi Air gun for suction and shooting a jet of compressed air)

  • 정석민;장성민
    • 한국산학기술학회논문지
    • /
    • 제13권11호
    • /
    • pp.4944-4949
    • /
    • 2012
  • 이 논문의 목적은 작업장에서 사용하기 위한 에어건의 개발에 관련된 것이다. 에어건은 공작기계를 사용하는 산업현장에서 공작물 칩과 절삭유의 제거를 위한 도구이다. 그리고 그것은 일반적으로 압축공기를 분사하는 용도로 사용된다. 작업자는 에어의 흡입과 분사를 위해 각각의 에어건을 준비하여야 한다. 따라서 우리는 새로운 에어건을 개발하였다. 이 논문에서 우리는 에어건의 설계와 분석을 위한 연구를 한다. 에어건은 몸체, 파이프, 개폐 유닛, 전환 유닛, 에어 튜브 그리고 조립을 위한 요소들로 구성된다. 개발된 에어건은 그 효율을 확인하기 위해 실험된다.

다수성이고 발근력이 강한 뽕품종 ′밀성뽕′육성 (Breeding of High Yielding and Easily Rootable Mulberry Cultivar ′Milsungppong′(Morus bombycis KOIDZ))

  • 성규병;김현복;남학우;이상욱;구태원
    • 한국잠사곤충학회지
    • /
    • 제43권1호
    • /
    • pp.9-15
    • /
    • 2001
  • New Mulberry Cultivar, Milsungppong, was selected from F1 seedlings obtained by crossing the female, 4X Keomseolppong, and the male, Kaeryangppong. Local adaptability test has been carried out at five places(Suwon, Chunchun, Cheongju, Kongju and Sangju) for four years since 1992. Leaf quality was tested by silkworm rearing for two silkworm rearing seasons(spring and autumn) at Suwon in 1995. From these tests, Milsungppong was found to be superior to control cultivar, cultivar, Kaeryangppong, in productivity, rootability and shoot cold injury. The new cultivar, Milsungppong, has following agronomic characteristics as compared with Kaeryangppong, the most prevailing cultivar, Milsungppong, has following agronomic characteristics as compared with Kaeryangppong, the most prevailing cultivar in Korea It is triploid cultivar belonging to Morus bombycis KOIDZ with the leaf shape of five lobes, sprouting in spring nearly the same to the Kaeryangppong (Morus alba L.), high leaf yielding of 25% compared to Kaeryangppong (Morus alba L.) and the medium degree of cold resistance. It is adaptable to every where in Korea except the area cold injury broken out habitually. Milsungppong is recommended to rear silkworms not only in spring but also in autumn besides for young silkworms.

  • PDF

New Stigmastane Steroids Constituents from Rice Hulls of Oryza sativa and Inhibitory Activity on Radish seed

  • Jeong, Il-Min;Ali, Mohd;Khanh, Tran Dang;Choung, Myoung-Gun;Park, Hong-Jae;Ahmad, Ateeque
    • Bulletin of the Korean Chemical Society
    • /
    • 제27권1호
    • /
    • pp.93-98
    • /
    • 2006
  • Two new compounds 1'-(stigmast-11,20(21),25-trien 3$\alpha$,9$\alpha$-diolyl)-3'-(pimara-11,15-dien-3$\alpha$-olyl) glycerol (1) and stigmast-5-en-3$\alpha$,26-diol (2) along with known fatty acids n-hexacosanoic acid (3) and hexadecanoic acid (4), have been isolated from the methanol extract of rice hulls of Oryza sativa. The structures of the compounds were elucidated using 1D and 2D NMR spectral methods, viz; $^1H, ^{13}C, ^{13}C$-DEPT, $^1H-^1H$ COSY, $^1H-^{13}C$ HETCOR, HSQC and HMBC aided by IR, EIMS, FABMS and HRFABMS. Compound (1) showed inhibition to radish germination, growth of shoot and root length.

Monosiphonous growth and cell-death in an unusual Bostrychia (Rhodomelaceae, Rhodophyta): B. anomala sp. nov.

  • West, John A.;Loiseaux de Goer, Susan;Zuccarello, Giuseppe C.
    • ALGAE
    • /
    • 제28권2호
    • /
    • pp.161-171
    • /
    • 2013
  • A morphologically distinct lineage within the Bostrychia moritziana-B. radicans species complex is described as a new species. Bostrychia anomala has thalli with branched monosiphonous filaments with apical cell divisions. The species has terminal tetrasporangial stichidia, each subtending cell bearing tetrasporangia with 2 cover cells. Discharged spores divide transversely, the lower cell first forming a narrow rhizoid and the upper cell forming a monosiphonous shoot. Females have subterminal procarps and males have terminal spermatangial stichidia. Carposporophytes are spherical. Isolates in culture show a pattern of cell death not associated with injury, reminiscent of programmed cell death. Bostrychia anomola shows cell death at intervals along the filaments resulting in division of adjacent cells on either side of the dead cell re-joining the filament; cell division of only one adjacent cell resulting in branching at that site; or filaments fragmenting at the cell death point with adjacent cells forming new apical cells, a means of thallus propagation. The cell death pattern could be a method of filament propagation in the mangrove environment where sexual reproduction is rare.

녹색과 분홍색의 포를 가진 다육식물 꽃기린 신품종 '파노라마' 육성 (A New Euphorbia Cultivar 'Panorama' with Green and Pink Colored Bract)

  • 박흥배;남상용;정재운;이정진;박인태
    • 한국육종학회지
    • /
    • 제42권6호
    • /
    • pp.717-720
    • /
    • 2010
  • 경기도농업기술원 선인장연구소에서는 다육식물 내수시장 확대를 위하여 1998년부터 국내의 재배농가와 종묘업체로부터 유전자원을 수집한 후 2001년부터 2009년에 걸쳐 교배 및 계통선발을 하고 3회의 특성검정을 거쳐서 꽃기린 신품종 '파노라마'를 육성하였다. 기존 꽃기린 품종은 포화엽색이 적색, 분홍색 등 단색인 품종이었으나 새로 육성된 '파노라마' 품종은 포화엽색이 녹색과 분홍색(RHS color chart 135B+54C)이 어우러진 복색이면서 고급스런 색체의 이미지를 준다. 측지수는 4.3개 발생하며 포화엽폭은 2.0 cm로 대륜성 품종이다. 줄기에 꽃차례 분지단수가 2~3개로 많이 발생하는 다화성으로 관상가치가 우수한 품종이다.