• Title/Summary/Keyword: Large-current

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Experimental Study on Current Capacity of Superconducting Solenoids with Large Inner Diameter (대구경 초전도 솔레노이드 코일의 전류특성의 실험적 고찰)

  • Bae, J.H.;Sim, K.D.;Choi, S.J.;Kim, S.W.;Cho, J.W.;Lee,, E.Y.;Kwon, Y.K.
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.688-690
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    • 2002
  • The quench current characteristics of the superconducting solenoids with large diameter were experimentally investigated. Three solenoids with the inside diameter of 450mm were fabricated and tested for various winding tensions and epoxy impregnation conditions. The highest quench current was obtained in the solenoid impregnated with epoxy after wound with winding tension of 20 percents. Although the training effect in the solenoid appeared after epoxy impregnation, The quench current of solenoid impregnated with epoxy was higher than that before impregnation. The test results and discussions were presented.

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CHARACTERISTICS OF A SUPERCONDUCTING AIR-CORE TRANSFORMER OF TOROIDAL SHAP (토로이드형 공심 초전도 변압기의 특성)

  • Choi, Kyeong-Dal;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.27-30
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    • 1991
  • With the recent development of high performance AC superconducting wire of very small ac loss and large current carrying capacity, the possibility of superconducting air core transformer is being studied. The air core transformer has merits of no iron loss, no insulation to the core and no harmonics. But the air core transformer has large exciting current and low magnetic coupling factor. To increase the coupling factor, the transformer of toroidal shape is proposed and designed. (10KVA, 110/220V) Compared with air core transformer of solenoidal shape, the performance is improved. The exciting current occupies about 22% of the rated current.

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Concept Design for Measurement against Large Fire Spreading based on BuildingDatabaseofaFolkCultureVillage

  • Umegane, Takuji;Uchida, Daisuke;Mishima, Nobuo;Wakuya, Hiroshi;Okazaki, Yasuhisa;Hayashida, Yukuo;Kitagawa, Keiko;Park, Sun-gyu;Oh, Yong-sun
    • Proceedings of the Korea Contents Association Conference
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    • 2015.05a
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    • pp.21-22
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    • 2015
  • This study aims to develop a current building condition database of an important folk culture village of South Korea considering their fire spread risk. We have selected a folk cultral village, and conducted field survey to reveal structure of buildings, materials of building wall, and roof style which make us understand current vulnerability of the village to fire spread. As a result, we made a current building condition database with map, which showed that the village had mixture of reinforced concrete and wood. Besides, we proposed a conceptual idea to prevent from large fire accident in the village.

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InAlAs/InGaAs schottky barrier enhanced metal semiconductor metal photodiode with very low dark current (매우 낮은 암전류를 가지는 schottky barrier enhanced InAlAs/InGaAs metal semiconductor metal 광다이오드)

  • 김정배;김문정;김성준
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.5
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    • pp.61-66
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    • 1997
  • In this paper we report the fabrication of an InGaAs metal-semiconductor-metal (MSM) photodiode(PD) which an InAlAs barrier enhancement layer that has very low dark current and high speed chracteristics. The detector using Cr/Au schottky metal fingers with 4um spacing on a large active area of 300*300um$^{2}$ offers a low dark current of 38nA at 10V, a low capacitance of 0.8pF, and a high 3-dB bandwidth of 2.4 GHz. To our knowledge, these characteristics are better than any previously published results obtained from large area InGaAs MSM PD's. The RC equivalent model and frequency domain current response model considering transit time were also used to analyze the frequency characteristic of the fabricated device.

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A Numerical Experiment on the Inter-annual Variation Induced by the Current in a Basin with Dimension Comparable to the East Sea

  • Cho Kyoung-Ho;Seung Young Ho
    • Fisheries and Aquatic Sciences
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    • v.3 no.2
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    • pp.163-171
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    • 2000
  • A series of numerical experiments are performed to examine the generation of inter-annual variations by an inertial current in an idealized semi-enclosed basin with dimension comparable to that of the East Sea. Model results indicate that the inter-annual variations dominate the kinetic energy spectrum with a peak around the time scales of 2-3 years. These variations are mostly due to the westward propagating meanders and large eddies induced by the instability of current, indicating their dependency on the eddy-resolving capacity of the model. They are generated in the interior of the basin but their energy is largely confined near the western boundary such that the east-west dimension of the basin cannot be considered as a critical factor as long as the basin covers enough western boundary region. Overall, this study suggests that the inter-annual variation observed in the East Sea is due to the meandering and large eddies induced by the instability of the current.

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A Study on Welding Perfomance Improvement using Short-Circuit Metal Transfer Induction on High-current $CO_2$ Arc Welding Machine ($CO_2$ 용접기의 대전류영역에서의 단락이행 유도에 대한 용접성능개선에 관한 연구)

  • 채영민;고재석;구자열;최규하;목형수;김규식;원충연
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.166-170
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    • 1998
  • The metal transfer of CO2 arc welding machine can be devided into short-circuit(low current) metal transfer. Especially in large crrent region, the main problem of CO2 arc welding machine is much spatter generation which is caused by mainly instant short-circuit matal transfer. So in this paper descrives new current control method in large current region, which can improve welding performance and lessen spatter generation. And as a result of experiment, the effect of proposed control method is demonstrated.

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A Voltage-Down Converter for Low-Voltage SoC

  • Yi Won-jae;Lee Se-chul;Kang Tae-kyoung;Lim Gyu-Ho;Huh Young;Park Mu-Hun;Kim Young-Hee
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.66-69
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    • 2004
  • This work is the study of Voltage-Down Converter used as internal supply voltage having large current driving and stable voltage level at any variation of process, voltage, and temperature(P.V.T). It converts VDD(external supply voltage) into $V_{1NT}(internal\;supply\;voltage).$ From the simulation results, a new Voltage-Down Converter has large current driving and a little stand-by current under lower supply voltage than conventional circuit. And bad characteristic of VINT, peaking, was eliminated. Start-up circuit for BGR is also added to one circuit, which consumes less current dissipation than convention circuit

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Development Trends of Tidal Current Energy and Its Test Bed (조류에너지의 이용기술)

  • Yang, Changjo;Hoang, T.G.
    • Vacuum Magazine
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    • v.3 no.2
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    • pp.11-16
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    • 2016
  • Tidal current energy is the most interesting renewable resources that have been less harnessed. Korea has globally outstanding tidal current energy resources and it is highly needed to develop a tidal current energy conversion system. It is reported that the total amount of available tidal current energy is approximately 6GW in Korea. A good tidal site candidate is required a large amount of fast moving water, bathymetry and seabed properties, no conflicts with other users and is close to a load and grid interconnection. In this review, we summarized the results of R&D projects regarding tidal current resources, utilization projects and demonstration test bed.

Design of a New Op-Amp for Driving Large-Size LCD Panels (대면적 LCD 패널 구동을 위한 새로운 Op-Amp설계)

  • 이동욱;권오경
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.133-136
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    • 2000
  • A new Op-Amp output buffer is presented for driving large-size LCD panels. The proposed Op-Amp is designed by combining a common source and a common drain amplifier to have a high slew rate and to minimize the quiescent current. The proposed circuits are simulated in a high-voltage 0.6${\mu}{\textrm}{m}$ CMOS process, dissipates only 20${\mu}{\textrm}{m}$ static current, and have 83dB open-loop DC gain and 60$^{\circ}$phase margin.

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A Numerical Analysis on the Development of ICP Source for Large Area LCD (대면적 LCD용 ICP소스에 대한 수치 해석적 분석)

  • 이주율;이영직
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.573-576
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    • 1998
  • In this paper, we analyzed electric field density and plasma condition to ICP reactor geometry structure, to generate plasma, to maintain plasma uniformity of large area LCD panel in ICP reactor also, we simulated electric field density for all kind existence current (antena and plasma current) in ICP reactor to analyze plasma antena structure

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