• Title/Summary/Keyword: Full cell

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Fuel Cell Generation Systems with Active Clamp Current fed Half Bridge Converter (능동 클램프 전류형 하프 브리지 컨버터를 적용한 연료전지 발전시스템)

  • Jang S. J.;Kim J. T.;Lee T. W.;Lee B. K.;Won C. Y.
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.1
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    • pp.78-86
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    • 2005
  • Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a dc-dc boost converter and dc-ac inverter to be used in fuel cell generation system. Therefore, this paper presents dc-dc active clamp current-fed half-bridge converter with ZVS for fuel cell generation system. The proposed converter has outstanding advantages over the conventional dc-dc converters with respect to high efficiency and high component utilization. The Fuel Cell generation system consist of active clamp current-fed half-bridge converter to boost the Fuel Cell(PEMFC) voltage(28∼43[Vdc]) to 380[Vdc]. A single phase full-bridge inverter is implemented to produce 220[Vac], 60[Hz] AC outputs.

One-stage reconstruction of full-thickness alar defects with a folded nasolabial island flap

  • Lee, Da Woon;Ryu, Hyeong Rae;Choi, Hwan Jun;Kim, Jun Hyuk
    • Archives of Craniofacial Surgery
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    • v.22 no.6
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    • pp.296-302
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    • 2021
  • Background: The reconstruction of large full-thickness alar defects requires complex surgical procedures that are usually performed in two stages, with concomitant disadvantages in terms of patient trauma, surgical risk, and cost. This study presents a functional folded nasolabial island flap (FNIF) that can be used to repair large-sized full-thickness alar defects in a straightforward manner. Methods: This retrospective study included seven patients who received a FNIF for a full-thickness alar defect between January 2007 and December 2020. The FNIF is different from the conventional nasolabial flap in that it is folded and twisted to achieve nostril reconstruction with a satisfactory three-dimensional mucosal lining in a single stage. The cosmetic and functional results of FNIF were evaluated by both patients and physicians. Results: The age ranged from 51 to 82 years (mean, 65.6 years). The causes of the defects were squamous cell carcinoma, basal cell carcinoma, and trigeminal trophic syndrome. The nostril lining did not collapse, there was no hypertrophic scarring, and air movement through the nostrils on the flap side was normal. Overall, FNIF produced excellent aesthetic and functional outcomes, with minimal patient discomfort. There were no postoperative complications. Conclusion: Compared with existing reconstruction methods for large full-thickness alar defects, FNIF can easily achieve aesthetic and functional success in a single-stage procedure. It provides satisfactory results for both the patient and the surgeon.

Feasibility Study of Tapped Inductor Filter Assisted Soft-Switching PWM DC-DC Power Converter

  • Moisseev S.;Sato S;Hamada S;Wakaoka M
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.231-234
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    • 2003
  • This paper presents a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control scheme DC-DC power converter, which can be used as power conditioner fur small-scale fuel cell power generation system. Using full-bridge soft-switching DC-DC converter topology makes possible to use low voltage high performance MOSFETs to achieve high efficiency of the power conditioner. A tapped inductor filter is implemented in the proposed soft-switching converter topology to achieve soft-switching PWM constant high frequency operation for a wide load variation range. to minimize circulating and idling currents without using additional resonant circuit and auxiliary power switching devices. The practical effectiveness of the proposed soft-switching DC-DC converter is verified in laboratory level experiment with 1 kW 100kHz breadboard setup using power MOSFETs. Actual efficiency of 94-96$\%$ is obtained for the wide load range

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A study on Characteristics of crystalline solar cell on local back contact according to passivation (결정질 태양전지 국부적 후면 접촉 Passivation에 따른 특성 연구)

  • Kim, Hyunyup;Choi, Jaewoo;Yi, Junsin
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.122.2-122.2
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    • 2011
  • 결정질 태양전지 제작에서, passavtion은 표면의 반사도를 줄여주는 반사 방지막의 역할과 표면의 dangling bond를 감소시켜, 표면 재결합 속도를 줄이고 minority carrier lifetime을 증가하는 데 큰 영향을 미친다. 그렇기 때문에 저가형 고효율 태양전지 제작에서 우수한 특성을 가지는 passivation막은 매우 중요한 이슈이다. 본 연구에서는 LBC(local back contact) 구조를 가지는 단결정 태양전지 후면에, 기존의 Full Al-BSF의 passivation 막을 SiNx와 ONO passivation 막으로 각각 대체하여, LBC 구조에서 더 적합한 passivation 막을 찾고자 하였다. SiNx와 ONO passivation 막은 단결정 LBC 구조 태양전지 후면에 각각 형성되었고 $800^{\circ}C$, 20 sec 조건으로 소성되었다. 실험결과는 minority carrier lifetime과 surface recombination velocity로 관찰하였다. 그 결과, SiNx passivation 막의 표면 재결합 속도는 29.7cm/s이고, ONO passivation 막의 표면 재결합 속도는 24.5cm/s로, Full Al-BSF 표면 재결합 속도 750cm/s에 비해 더 적합한 passivation 막으로 확인할 수 있었다. 결과적으로 SiNx,ONO passivation 막이 Full Al-BSF보다 전극에 수집되는 캐리어의 양이 많아짐에 따라 효율향상을 가져올 수 있을 것이다.

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Ex-situ conservation and cytotoxic activity assessment of native medicinal orchid: Coelogyne stricta

  • Thapa, Bir Bahadur;Thakuri, Laxmi Sen;Joshi, Pusp Raj;Chand, Krishna;Rajbahak, Sabari;Sah, Anil Kumar;Shrestha, Resha;Paudel, Mukti Ram;Park, So Young;Pant, Bijaya
    • Journal of Plant Biotechnology
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    • v.47 no.4
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    • pp.330-336
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    • 2020
  • Ex-situ conservation of the ornamental and medicinal orchid, Coelogyne stricta, was performed by mass propagation using seed culture. Propagation stages were optimized using full- and half-strength solidified MS medium with different phytohormones. Maximum seed germination (88 ± 0.5% over 6 weeks of culture) was achieved on half-strength MS medium supplemented with 15% coconut water. Maximum shoot numbers were found on full-strength MS medium supplemented with 1 mg/L BAP, 2 mg/L Kinetin, and 10% coconut water, while the longest root was developed on full-strength MS medium with 1.5 mg/L IBA. A 2:1:1 combination of coco-peat, pine bark, and sphagnum moss was found to be a suitable potting mixture resulting in 80% seedling survivability. The cytotoxic activity of extracts of both wild plants and in vitro-developed protocorms was determined using an MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay on a cervical cancer cell line. The wild plant extract inhibited the growth of 41.99% of cells, showing that this extract has moderate cytotoxic activity toward cervical cancer cells.

Effects of Moist Extruded Full-fat Soybeans on Gut Morphology and Mucosal Cell Turnover Time of Weanling Pigs

  • Qiao, Shiyan;Li, Defa;Jiang, Jianyang;Zhou, Hongjie;Li, Jingsu;Thacker, P.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.1
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    • pp.63-69
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    • 2003
  • Ten barrows, weaned at 28 days (7.2$\pm$0.1 kg BW), were used to evaluate the effects of feeding extruded full-fat soybeans on intestinal morphology and mucosal cell turnover time. All pigs were fed corn-based diets with half of the pigs receiving diets supplemented with 15.5% soybean meal and 3% soybean oil and the remaining pigs fed a diet in which the soybean meal and oil were replaced by 18.5% extruded full-fat soybeans. The pigs were individually placed in $80{\times}150cm$ metabolic cages and fed twice daily an amount approximately equal to their ad libitum intake for a period of 14 days. On day 14, pigs were weighed and then injected intraperitoneally with $^3$H]thymidine ($100{\mu}Ci/kg$ of BW, specific activity 20 Ci/mmol) 6 h after the morning meal. A pig from each treatment was killed 1, 4, 8, 16, or 24 h postinjection and intestinal tissues were collected. Daily gains for pigs fed the soybean diet and extruded full-fat soybean diet were 0.24 and 0.31 kg/day (p=0.05) with feed conversions of 1.58 and 1.39 (p=0.05), respectively. In comparison with pigs fed soybean meal, pigs fed moist extruded full-fat soybeans had a decreased crypt depth in their duodenum and cecum (p<0.1), while the villus height in the mid jejunum and ileum and the total height (villus height plus crypt depth) of the ileum and mid jejunum increased (p<0.05). The villus width in the duodenum and mid jejunum decreased (p<0.05). The number of crypt epithelial cells in the upper jejunum increased but decreased in the ileum, colon and cecum (p<0.05). The number of villus epithelial cells in the ileum and the upper and mid jejunum increased (p<0.05). The time for migration of epithelial cells in the crypt-villus column decreased (p<0.05) in all sites except the upper jejunum, ileum and cecum. The mucosal turnover rate for all intestinal sites except the upper jejunum, colon and cecum decreased (p<0.05). From these data, we conclude that inclusion of moist extruded full-fat soybeans in weanling pig diets can improve the intestinal morphology and slow the migration rate and turnover time of epithelial cells of the small intestine, especially in the mid jejunum compared with soybean meal.