• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권11호
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• pp.557-562
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• 2003

To develop a stable and compact small-sized superconducting magnetic energy storage (SMES) system, which provides electric power with high quality to sensitive electric loads, we fabricated a SMES coil and tested it. Because such a large-sized superconducting coil quenches far away from its critical current, the recovery current is frequently used as a stability criterion in the coil fabrication. Therefore, we first investigated the recovery current characteristics of the large current conductor, which was used in our SMES coil fabrication. The test results indicate that the recovery currents measured in the conductor are nearly identical to those based on the single wire. This implies that the recovery current is affected by the conductor's cooling condition rather than its size and current capacity. In the SMES coil test the first quench occurred at 1250 A, which is equivalent to the stored energy of about 2 MJ. It corresponds to the quench current density of about $130A/mm^2$ This value is much higher in comparison with that reported in the other work. In addition, the first quench current of the coil agrees well with the measured recovery current of the conductor having similar cooling condition with it. This means that to determine the recovery current of a conductor is, first of all, important in the design and fabrication of a large-sized superconducting coil.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.292-292
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• 2008

The superconducting fault current limiter(SFCL) can be used to limit fault current level in electrical transmission line and power system. Up to now, there are several kinds of SFCL that have proposed and it is expects that they will be applied to appropriated position considering their own properties; initial fault current limiting instant and the current limiting characteristics. In this paper, we investigated the initial fault current limiting instant and the amplitude of initial fault current in the resistive type, the flux-lock type, the flux-coupling type and the transformer type SFCL. Experiment results show that the initial fault current limiting instant and the amplitude of initial fault current of the SFCLs are dependant on the ratio of inductance of primary and secondary coils.

• 한국수자원학회논문집
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• 제56권8호
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• pp.521-528
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• 2023

FUNWAVE 이안류 수치모의를 통해 얻은 이안류 발생정도 분포(파고-주기, 파고-조위, 파고-파향, 파고-주파수 스펙트럼 광협도, 파고-파향 스펙트럼 광협도)를 이용한 이안류 위험지수 생산 기법을 이안류 예보체계에 적용하였다. 이 기법은 관측 기반의 실시간 이안류 경보체계를 위해 개발되었으나, 관측정보를 대신하여 파랑예보 정보를 사용하므로 예보체계에 활용하였다. 2021년 해운대 해수욕장에 대하여 관측 기반으로 생산된 이안류 위험지수와 파랑예보 기반의 지수를 비교하여 그 가능성을 검토하였다.

• 대한전기학회논문지
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• 제39권12호
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• pp.1317-1320
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• 1990

The inductive reactance losses of a superconducting current generator built at Case Western Reserve University has been analyzed. The calculations of the field in the spot make it possible to estimate the spot inductance as well as the filament inductance on the foil. It is shown that magnetic energy lost in switching the current is mainly due to the amplitude of the fluctuation in voltage associated with the inductive reactance losses of a superconducting current generator.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.68-69
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• 2011

Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the peak current controlled (PCC) buck converter with a wide input voltage. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

• 대한전기학회논문지
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• 제36권8호
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• pp.539-546
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• 1987

In case of operating at Variable speed the induction motor by a frequency transformer, it will cause ripples in motor torque and considerably bad effects on the machines because the output side of the frequency transformer involves a great number of harmonics. This paper Presents the methods of decreasing torque ripples in induction motor and of improving current waveform, by means of forming the waveforms of output current into multi-step waveforms similiar to sinusoid, and also by means of eliminating the harmonic components maximally, in case of operating a 18-phase multi-inverter combining 3-step current source inverter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2063-2064
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• 2006

The power source of inverter welder stable power of low voltage and high current. Because if shouldn't be, it is caused to spark between the parent metal and the peak. So that, we designed to be base on high frequency transformer and reactor of DC part. Then, we optimized control of PWM, current rising slant, voltage, current, pulse current and inverter out-put voltage. Also we designed PCB for EMI and noises.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.13-15
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• 1999

A Josephson sampler circuit using high-Tc superconductor (HTS) ramp-edge junctions has been designed, fabricated, and experimentally tested. It consists of five ramp-edge junctions with a stacked groundplane and is based on single-flux-quantum (SFQ) operations. The sampler was used to measure current waveforms at picosecond and microampere resolutions. We are developing a system based on the sampler for measuring the current waveform in a room-temperature sample. And measuring current flowing through wiring in a semiconductor large-scale integrated circuit is a promising application for the HTS sampler system.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1093-1096
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• 2008

The circuit simulation has been done on the current-programmed AMOLED and shows that the circuit which behaves as a negative capacitance can reduce the effect of parasitic capacitance fixed on the data-line and can accelerate the current programming speed as high as that required in Full HD AMOLED.

• 한국해양학회지
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• 제19권2호
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• pp.195-199
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• 1984

풍파발생초기 세계에서 바람에 의해 형성된 취송류가 초기 단계의 파의 특성을 결정하는데 미치는 영향을 이론적으로 다루었다. 본 연구의 관점은 Phillips(1957)의 풍파발생이론의 관점과 유사하다. 취송류를 고려하면 Phillips가 구한 결과를 상당히 변경시키는 것으로 판명되었다. 특히 공명 조건에 있어서 취송류가 큰 역할을 하고 있다.