• 제목/요약/키워드: Transport loss

검색결과 604건 처리시간 0.036초

Coated Conductor를 사용한 무유도 팬케이크형 한류 코일의 통전 손실 특성 (Transport Loss Characteristic of the Bifilar Pancake Type Fault Current Limiting Coil using Coated Conductor)

  • 박동근;방주석;양성은;안민철;심기덕;윤용수;남관우;석복렬;고태국
    • 한국초전도ㆍ저온공학회논문지
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    • 제9권3호
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    • pp.21-25
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    • 2007
  • Superconducting fault current limiter (SFCL) is attractive apparatus to reduce fault current in power grid. Since it is applied to the alternating current (AC) power line, the SFCL has losses in the normal operation. Recently, coated conductor (CC) is noticeable material employed for resistive bifilar winding type SFCL in many research groups. Bifilar structure is expected to have low AC loss by magnetic field offset as compared with the single tape structure in the same length. This paper reports about characteristic of bifilar pancake type coil for SFCL application in AC loss aspect. The bifilar coil is wound using CC with facing on HTS sides each other. Transport AC loss measurement and characteristic analysis of the bifilar coil using CC have been performed at 77K. The test results are compared with the Norris equations and the test results of non-inductively wound paralleled solenoid type coil which is suggested and tested in this group at present.

Effects of Sodium Fluoride on the Water Transport in Leaves of Barley and Rice under Salt Stress in the Light

  • Hwang, Hong-Jin;Oh, Kwang-Hoon;Park, Phun-Bum;Lee, Choon-Hwan
    • Journal of Photoscience
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    • 제11권1호
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    • pp.25-28
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    • 2004
  • The kinetics of the loss of leaf fresh weight during incubation of barley and rice leaves in 9% or 15% NaCl solutions were biphasic, indicating the existence of a controlling mechanism for water transport. The first rapid phases reached their plateaus within 1 and 2 h in the case of rice and barley leaves, respectively. When barley leaves were fed with sodium fluoride, an inhibitor of phosphatase inhibitor, through their epicotyls for 3 h in darkness, prior to the treatment of NaCl, the biphasic pattern shown during NaCl treatment was disappeared resulting in linear decreases in the relative fresh weights. The results suggest that NaF accelerates salt-induced water efflux from plant cells, possibly by inhibiting the protection mechanism that may act in NaF-untreated leaves. The linear water loss can be explained in terms of phosphorylation of aquaporin by blocking its dephosphorylation in the presence of the phosphatase inhibitor to keep aquaporin in a phosphorylated form. However, the effect of NaF shown in barley leaves were not observed in rice. These results suggest that the regulation of water transport depends on plant species, and the mechanism for the controlling water transport in rice is different from that of barley.

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A Survey on Transport Protocols for Wireless Multimedia Sensor Networks

  • Costa, Daniel G.;Guedes, Luiz Affonso
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제6권1호
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    • pp.241-269
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    • 2012
  • Wireless networks composed of multimedia-enabled resource-constrained sensor nodes have enriched a large set of monitoring sensing applications. In such communication scenario, however, new challenges in data transmission and energy-efficiency have arisen due to the stringent requirements of those sensor networks. Generally, congested nodes may deplete the energy of the active congested paths toward the sink and incur in undesired communication delay and packet dropping, while bit errors during transmission may negatively impact the end-to-end quality of the received data. Many approaches have been proposed to face congestion and provide reliable communications in wireless sensor networks, usually employing some transport protocol that address one or both of these issues. Nevertheless, due to the unique characteristics of multimedia-based wireless sensor networks, notably minimum bandwidth demand, bounded delay and reduced energy consumption requirement, communication protocols from traditional scalar wireless sensor networks are not suitable for multimedia sensor networks. In the last decade, such requirements have fostered research in adapting existing protocols or proposing new protocols from scratch. We survey the state of the art of transport protocols for wireless multimedia sensor networks, addressing the recent developments and proposed strategies for congestion control and loss recovery. Future research directions are also discussed, outlining the remaining challenges and promising investigation areas.

고온초전도체의 자기자계손실 측정 (Measurement of the Self-field Loss in the HTS Tape)

  • 심정욱;차귀수;이지광;한승엽
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 A
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    • pp.274-276
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    • 1999
  • Transport current is the HTS tape generates the self field loss. To measure the self field loss, rectangular voltage tap has been used. In this paper, self field loss was measured using the spiral voltage tap method. Result of the measurement was compared with that of the theoretical.

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수송거리에 따른 녹숙 및 적숙 토마토의 품질변화 (Transport Distance Affects the Quality of Both Mature and Ripe Tomato Fruits)

  • 박권우;강호민
    • 원예과학기술지
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    • 제16권4호
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    • pp.511-513
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    • 1998
  • 토마토를 녹숙과(mature green에서 breaker 단계)와 적숙과(pink에서 red단계)로 수확하여 200km와 400km의 거리를 수송한 후 과실의 품질을 비교하였다. 수송후 열과와 찰상을 더한 손실율은 녹숙과 200km는 11%로 가장 적었으며 녹숙과 400km는 13.5%, 적숙과 200km는 20.5%, 400km는 45.5%의 손실율을 보였다. 경도를 보면 녹숙과가 적숙과보다 1.55배가 높아 원거리 수송에 적합함을 알 수 있었다. 수송거리별로 보면 역시 수송거리가 먼 400km에서 경도 감소가 많았으며 상자내 위치로는 하부에서 감소가 컸다. 비타민 C 함량은 적숙과가 녹숙과의 1.25배 많았으며 경도와 마찬가지로 400km와 상자내 하부에서 감소가 컸다. 수송후 손실율로 볼 때 적숙과는 200km이하의 단거리 수송이 필요하며, 400km이상의 원거리 수송에서는 녹숙과가 적합하다고 생각된다. 따라서 토마토를 수송할 때는 과실의 성숙 정도와 수송거리를 반드시 고려해야 할 것으로 제시한다.

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AC Loss Characteristics of Multifilamentary HTS Tapes

  • Amemiya, Naoyuki
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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    • pp.69-72
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    • 2000
  • AC losses in multifilamentary HTS tapes can be classified to hysteresis loss, coupling loss, and eddy current loss from the viewpoint of their generation mechanism. From the viewpoint of the major magnetic field component generating them, they can be classified to magnetization loss, transport loss, and total loss. Dividing superconductor to fine filaments, twisting filaments bundle and increasing transverse resistivity are effectively reduce magnetization loss and total loss when the external magnetic field is relatively large. Recently, twisted multifilamentary Bi 2223 tapes with pure silver matrix were fabricated and the reduction of magnetization loss was proved experimentally in the parallel magnetic field to the tape wide face. However, when the perpendicular magnetic field is applied, increasing transverse resistivity is required essentially to reduce the AC losses. The transverse resistivity was increased successfully by the introduction of resistive barrier between filaments.

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DMM의 패킷 손실 감소 방안 제안 및 성능 비교 (Proposal and Performance Comparison for a Packet Loss Reduction Scheme of DMM)

  • 하상혁;민상원
    • 한국ITS학회 논문지
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    • 제11권6호
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    • pp.89-94
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    • 2012
  • 본 논문에서는 DMM의 우수성을 나타내기 위해 PMIPv6와 트래픽 부하 변화, 패킷 전달 지연시간에 대해 성능 비교 분석하였다. 그리고 DMM에서 기술한 핸드오버 시 패킷 손실이 발생하는 문제점을 줄이기 위해 핸드오버 이전 MAAR에 버퍼를 생성하는 방안에 대해 연구하였다. DMM의 우수성과 패킷 손실을 줄이기 위한 방안을 분석하였으며, 같은 네트워크 서비스 환경임에도 불구하고 PMIPv6보다 DMM이 트래픽 부하 변화 및 패킷 전달 지연시간 측면에서 확실히 성능이 우수함을 확인하였다. 그리고 제안한 DMM의 버퍼링 방안 성능이 기존 DMM의 핸드오버 절차에 비해 패킷 손실이 줄었음을 입증하였다.

무선 ATM 액세스 전달구조에서 VBR 트래픽에 대한 셀 스케일과 호 접속레벨간의 관계 (The Relation of Cell Scale and Call Connection Level for the VBR Trafac in the Wireless ATM Access Transport)

  • 이하철
    • 한국통신학회논문지
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    • 제30권9B호
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    • pp.596-601
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    • 2005
  • In this paper it is focused on the relation between CLR(Cell Loss Ratio) and blocking probability in the wireless ATM access transport. Traffic model of wireless ATH access transport is based on the cell scale, burst scale and call connection level. The CLR due to buffer overflow for wireless access node is derived for VBR traffic. The CLR due to transmission errors for wireless channel is derived. Using the CLR for both access node and wireless channel: the CLR of wireless ATM access transport is derived. The relation between CLR and blocking probability is analyzed for VBR traffic to evaluate performance of wireless ATM access transport.

Decursinol 처리에 따른 보리 유식물의 전자전달 활성과 엽록소-단백질 복합체의 변화에 대하여 (Changes of Chloroplast-Mediated Electron Transport Activity and Chlorophyll-Protein Complexes in Barley Seedlings by Decursinol)

  • 이현식
    • Journal of Plant Biology
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    • 제31권2호
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    • pp.131-141
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    • 1988
  • The effects of decursinol and decursin on chloroplast-mediated electron transport and phosphorylation in barley seedlings were investigated in comparison with coumarin in the dark or light. The changes of CP-complexes were also studied. Decursinol, decursin and coumarin caused marked inhibitory effects on germination of seed and electron transport and phosphorylation activity of seedlings. The following order of inhibitory effectiveness was exhibited; decursinol>coumarin>decursin. Loss of chlorophyll and decrease of electron transport activity were retarded in the dark, but were reversely accelerated in the light by these three chemicals. The changes of CP-complex patterns were also similar to effects on chlorophyll content and the electron transport activity. These opposite effect in the dark and light suggest that these three chemicals act as natural growth retardants rather than cytokinins or growth inhibitors.

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