• 제목/요약/키워드: Large-current

검색결과 5,209건 처리시간 0.037초

저에너지 대면적 전자빔 발생장치의 이론적 해석 및 설계에 관한 연구 (Theoreticel Analysis and Design of the Low-Energy Large-Aperture Electron Beam Generator)

  • 우성훈;이광식
    • 조명전기설비학회논문지
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    • 제13권3호
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    • pp.40-47
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    • 1999
  • 본 연구에서는 개발하고자 하는 저에너지 대면적 전자빔 발생장치는 원리로서 발생원인 글로우 발전에 의한 플라즈마로부터 이온을 음극으로 가속, 충돌하게 하여 그때 발생하는 2차전자를 전자빔원으로 하여 전자를 가속·제어하는데 바탕을 두고 있으며, 본 연구에서는 이러한 원리를 기본으로 이론적 해석을 통한 고효율의 저에너지 대면적 전자빔 발생장치개발의 설계 및 제작에 대해서 연구하였으며, 또한 빔 에너지의 안전성과 방전조건을 고려한 최적의 방전 파라메타를 설정하여 대면적의 균일한 빔 인출을 가능케 하였다.

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Key parameters of toroidal HTS coil for a superconducting magnetic energy storage system

  • Miyeon, Yoon;Jinwoo, Han;Ji-Kwang, Lee;Kyeongdal, Choi;Jung Tae, Lee;Seungyong, Hahn;Woo-Seok, Kim
    • 한국초전도ㆍ저온공학회논문지
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    • 제24권4호
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    • pp.50-54
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    • 2022
  • High temperature superconducting (HTS) magnets for large-capacity energy storage system need to be composed of toroid magnets with high energy density, low leakage magnetic fields, and easy installation. To realize such a large capacity of a toroid HTS magnet, an HTS cable with large current capacity would be preferred because of the limited DC link voltage and instantaneous high power required for compensation of the disturbance in the power grid. In this paper, the optimal operating strategies of the SMES for peak load reduction of the microgrid system were calculated according to the load variation characteristics, and the effect of compensation of the frequency change in microgrid with a SMES were also simulated. Based on the result of the simulation, key design parameters of SMES coil were presented for two cases to define the specification of the HTS cable with large current capacities for winding of HTS toroid coils, which will be need for development of the HTS cable as a future work.

체내 이식형 인공심장의 무선에너지 전송 시스템에 관한 기초적 연구 (The basic research of transcutaneous energy transmission system for totally implantable artificial heart)

  • 김정한;김동욱
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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    • pp.407-410
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    • 2002
  • As a part of electro-mechanical totally implantable artificial heart, a transcutaneous energy transmission system has been developed. By mutual magnetic induction between the first coil on the skin and the subcutaneously implanted second coil, the system transfers electrical power through the skin. This research aimed a minimizing the size of the implanted part as well as maximizing the transfer efficiency. When an air gap is 1$\sim$2cm, voltage gain and current gain low and it is hard to transfer energy due to large leakage flux. That is, the required input voltage and input current must be large compared with the output voltage and output current, respectively, This paper research the inverter topology and the control method in order to increase the voltage gain and the current gain. For this purpose, this inverter employs double tune to compensate the large leakage inductance of primary and secondary of the transcutaneous transformer. And the output energy of transcutaneous energy transmission system supply for Lithium-ion battery charger.

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냉음극형 대면적 전자빔의 공간적 분포 특성 (Characteristics of spatial distribution of cold cathode type large aperture electron beam)

  • 우성훈;;조주현;김광훈;이홍식;임근희;이광식
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 E
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    • pp.2170-2172
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    • 1999
  • A low energy large aperture(LELA) pulsed electron beam generator of a cold cathode type has been developed for environmental applications, for example, waste water cleaning, flue gas cleaning, and pasteurization etc. The operational principle is based on the emission of secondary electrons from cold cathode when ions in the plasma hit the cathode, which are accelerated toward exit window by the gradient of an electric potential. We have fabricated the LELA electron beam generator with the peak energy of 200keV and beam diameter of 200mm and obtained the large aperture electron beam in air. The electron beam current density has been investigated as a function of glow discharge current, accelerating voltage and radial distribution in front of the exit window foil. The plasma density and electron temperature have been measured in order to confirm the relation with the electron beam current density. We are going to upgrade the LELA electron beam generator in the electron energy, electron beam current and stability of operation for various applications.

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배전계통에 대용량변압기 교체 적용시 초전도 한류기의 임피던스에 따른 순간전압 분석 (Analysis on Voltage Sag in Power Distribution System according to SFCL's Impedance for Protective Coordination with Large Transformer)

  • 김진석;문종필
    • 전기학회논문지P
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    • 제63권4호
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    • pp.312-316
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    • 2014
  • In this paper, a voltage sag is analyzed in case of superconducting fault current limiter (SFCL) installed in power distribution system where replaces the main power transformer to large one to meet the power demand. First, the power system is configurated to analyze the operation characteristics of the protective relay with replacement of the main transformer and application of the SFCL. Next, the method to meet the protection coordination is analyzed with large transformer using PSCAD/EMTDC. Finally, the bus voltage is investigated according to the impedance of both main transformer and SFCL in case that the SFCL is applied into feeder.

디지털시대의 대형사고의 전기적 영향 고찰 (Electric power system effect investigation of large size digital signal accident thought in digital age)

  • 강태근
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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    • pp.575-580
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    • 2004
  • The latest equipment automatic Intelligence of digital base done large size equipment appear in succession. That run by voltage electric current(mA, mV, ${\mu}A,\;{\mu}V$) that outline is microscopic of action of accuracy large size equipment of this digital base is bulk. Have received influence that is great in river electric field by installment that use computer. Most of domestic working voltage from service entrance extra-high voltage and working voltage of commercial frequency 60Hz working voltage 220V that use our country outside 1 country in interior of 22.900V for semiconductor use computer use digital installment of appliance as well as various smalls of digital base, middle, large size that safety is these fine voltage electric current that is not enough direct admonition hundred vast damage give can. Also, already act in surge circle and impulse transient phenomena such as several thousands, myriads, strong bit error more than billions time to digital fine electronic circuit by mistake use of using electric facility system of system electric power.

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Current Concepts and Recent Trends in Arthroscopic Treatment of Large to Massive Rotator Cuff Tears: A Review

  • Rho, Joseph Y.;Kwon, Yong suk;Choi, Sungwook
    • Clinics in Shoulder and Elbow
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    • 제22권1호
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    • pp.50-57
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    • 2019
  • Rotator cuff tear is a common cause of shoulder pain and disability in adults. Due to the various nature of progression of rotator cuff tears and the complex biomechanics of the shoulder joint, repair and treatment of large-to-massive tears are challenging for many surgeons. Despite the recent popularity of reverse total shoulder arthroplasty as a treatment option for large-to-massive irreparable rotator cuff tears, biological and mechanical repair augmentation has also shown promise as a viable treatment option. The purpose of this study was to briefly summarize and review current studies on the assessment and arthroscopic treatment of large-to-massive rotator cuff tears, whether repairable or irreparable, to aid in developing a consensus on future treatment directions.

Full Color Large Area Flexible Plasma Displays

  • Wedding, Carol;Strbik, Oliver;Peters, Edwin
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1237-1239
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    • 2008
  • Imaging Systems Technology is conducting research and development in large area flexible plasma displays. These displays will be used for low cost dynamic signage and billboards. In this paper, IST will report its current progress in achieving very bright full color displays.

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자연 산화막과 엑시머 레이저를 이용한 Poly-Si/a-Si 이중 박막 다결정 실리콘 박막 트랜지스터 (Poly-Si Thin Film Transistor with poly-Si/a-Si Double Active Layer Fabricated by Employing Native Oxide and Excimer Laser Annealing)

  • 박기찬;박진우;정상훈;한민구
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제49권1호
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    • pp.24-29
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    • 2000
  • We propose a simple method to control the crystallization depth of amorphous silicon (a-Si) deposited by PECVD or LPCVD during the excimer laser annealing (ELA). Employing the new method, we have formed poly-Si/a-Si double film and fabricated a new poly-Si TFT with vertical a-Si offsets between the poly-Si channel and the source/drain of TFT without any additional photo-lithography process. The maximum leakage current of the new poly-Si TFT decreased about 80% due to the highly resistive vertical a-Si offsets which reduce the peak electric field in drain depletion region and suppress electron-hole pair generation. In ON state, current flows spreading down through broad a-Si cross-section in the vertical a-Si offsets and the current density in the drain depletion region where large electric field is applied is reduced. The stability of poly-Si TFT has been improved noticeably by suppressing trap state generation in drain region which is caused by high current density and large electric field. For example, ON current of the new TFT decreased only 7% at a stress condition where ON current of conventional TFT decreased 89%.

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Fabrication of 6-superconducting layered HTS wire for high engineering critical current density

  • Kim, Gwantae;Ha, Hongsoo;Kim, Hosup;Oh, Sangsoo;Lee, Jaehun;Moon, Seunghyun
    • 한국초전도ㆍ저온공학회논문지
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    • 제23권4호
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    • pp.10-13
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    • 2021
  • Recently, cable conductors composed of numerous coated conductors have been developed to transport huge current for large-scale applications, for example accelerators and fusion reactors. Various cable conductors such as CORC (Conductor on round core), Roebel Cable, and TSTC (Twisted stacked tape cable) have been designed and tested to apply for large-scale applications. But, these cable conductors cannot improve the engineering critical current density (Je) because they are made by simple stacking of coated conductors. In this study, multi-HTS (High temperature superconductor) layers on one substrate (MHOS) wire was fabricated to increase the engineering critical current density by using the exfoliation of superconducting layer from substrate and silver diffusion bonding method. By the repetition of these processes, the 10 m long 6-layer MHOS conductor was successfully fabricated without any intermediate layers like buffer or solder. 6-layer MHOS conductor exhibited a high critical current of 2,460A/12mm-w. and high engineering critical current density of 1,367A/mm2 at liquid nitrogen temperature.