• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.136-142
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• 2006

A damped sinusoidal electromagnetic pulse generator was designed, fabricated and tested. The pulse generator consisted of an oscillator(a spark gap switch and an initially charged low impedance line) and a high impedance antenna. This generator was capable of producing damped sinusoidal pulses at closure of the spark gap switch. A Marx generator was employed to supply the Pulse generator with high voltage pulses. While the pulse generator was provided with the high voltage pulses of 200kV from the Marx generator, its output power was maximized by controlling the pressure of the gas contained in the spark gap switch. The output power of the damped sinusoidal electromagnetic pulse oscillator was 1.3GW and the amplitude of electric field radiated from the pulse generator was 4kV/m at the range of 25m.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.82-90
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• 1999

A pulse frequency control method for single-switch three-phase buck rectifiers is comprehensively studied in this paper. The proposed pulse frequency control method leads the three-phase buck rectifier to a high performance system that can draw the nearly sinusoidal input-line currents. The simulated and experimental results demonstrate that the system provides low total harmonic distortion of the input-line currents, high-power factor, and good output voltage regulation against load change.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.304-309
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• 1999

In this paper, a new 24longleftarrowpulse diode rectifier system based upon the conventional series-connected 12-pulse rectifier is p proposed with the least number of switching devices and low VA rating of the additional passive components. The p proposed approach does not employ any active switching devices. Therefore, the system is rugged and simple to i implement. Detailed analysis with VA rating calculation of the components is presented and experimental results from a a 220V, 3kV A rectifier system verify the proposed concept.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.39-46
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• 2004

This paper presents the realization schemes for a multipurpose coherent mono-pulse radar Simulator with extendable features. We developed and installed the TSG(Timing Signal Generator) board which can simulate a mechanically rotate signal of antenna, an operation timing signal of pulse radar and target signal, to operate the simulator without real target in the indoor environment. Also, with the insertion of the radar signal processor, it came to be easy to achieve the addition of radar function algorithms, to rebuild or extend the multi-DSP Architecture into the simulator. Throughout the simulation results, we verified that the designed coherent mono-pulse radar simulator can exactly display a moving target on the realistic monitor(RD 9800).

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.503-506
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• 2001

When DC voltages from 5 V up to 90 V are applied to a transmitter chip excited by an ultrafast lacer beam, the terahertz electromagnetic pulses and their spectra are changed. The spectrum shifts to the high frequency range when the high DC voltage is applied to the chip. At that time, the signal-to-noise ratio is increased from 250: 1 to 10,000: 1. The spectrum can expand up to 4 THz by optimal realignment of the THz system. Also, two terahertz electromagnetic pulses are generated from a receiver chip when the laser detection beam is reflected to the back side of the chip.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.273-273
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• 2012

컷오프 진단법은 두 개의 탐침 형태로 제작된 마이크로 웨이브 진단법으로, 간단한 수식을 통해 전자밀도, 전자온도 등을 측정할 수 있다. 컷오프 탐침은 방사 안테나, 측정 안테나와 네트워크 분석기로 구성되어 있다. 네트워크 분석기는 두 안테나 사이의 플라즈마 투과 스펙트럼을 만드는데 쓰이며, 스펙트럼 분석을 통해 플라즈마 변수들을 측정할 수 있다. 이 진단법은 장치나 분석방법이 매우 간단한 장점을 지니며, 약 1 mW 정도의 적은 파워를 사용하여 플라즈마 상태를 거의 변화시키지 않는 측정이 가능하다. 또한 CF4와 같은 공정 가스를 이용한 플라즈마에서도 사용이 가능하다. 그러나 컷오프 진단법을 사용한 측정은 다른 종류의 진단법과 마찬가지로, 약 1초 정도의 긴 시간을 필요로 하는 단점이 있어, 펄스 플라즈마나 토카막과 같이 빠르게 변하는 플라즈마를 측정하기에는 무리가 있다. 최근에 개발된 푸리에 컷오프 탐침(Fourier Cutoff Probe, FCP)는 기존의 컷오프 탐침의 느린 시간분해능을 개선하기 위해 개발되었다. [1] 펄스 형태의 단일신호를 플라즈마를 투과하기 전후로 비교하면 투과 스펙트럼 및 플라즈마 변수들을 얻을 수 있으며, 기존 연구에서 구한 시간 분해능은 약 15 나노초였다. 이 값은 펄스 발생장치의 스펙에 따라 변하게 된다. 펄스폭이 짧을수록 시간분해능이 좋아지지만, 무한정 좋아질 수는 없다. 이 논문에서는 FCP 측정의 시간 분해능을 이론적으로 구하고, 시간 분해능의 이론적 한계를 구했다.

• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.1-4
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• 2001

Via terahertz (THz) reflection radar, the characterizations of reflected THz electromagnetic pulses are reported. Quasi-optical techniques are used to efficiently reflect pulses of THz electromagnetic radiation from an aluminum mirror and several conducting and nonconducting materials. An incident THz pulse is reflected up to 9 times to know the magnitude change of a reflected pulse from the aluminum mirror. Using this method, aluminum board, undoped silicon, quartz, and LDPE samples' reflection coefficient and index of refraction can be measured. These results suggest a possible application of transient THz reflection spectroscopy without surface contact.ontact.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.430-434
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• 2002

We present the magnitude of terahertz electromagnetic pulses when femtosecond laser pulses are moving along to a dipole antenna. The dipole antenna chip has maximum 4.7 nA THz current, generated at 11 DC volt. This current is 3.4 times bigger than the current of a $300{\mu}{\textrm}{m}$ separated transmission line structure chip that has 70 DC volt. We also apply an AC square wave voltage to the dipole antenna from 0.1 volt to 10 volt for binary signals using the terahertz electromagnetic pulses.

• KIPE Magazine
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• v.9 no.1
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• pp.20-25
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• 2004

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.98-102
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• 2002

플랜트, 가스용기 등의 압력용기 제작 및 스텐레스, 알미늄 등의 특수금속용접에서 TIG 용접은 매우 중요한 기술적 위치를 차지하고 있다. 이런 용접에서 현재까지는 국내에서 노동 집약적인 수동 TIG 용접이 적용되고 있으나 인건비의 상승, 3D 산업으로 인한 숙련자의 부족으로 자동화가 급속히 추진되고 있다. 따라서 본 연구에서는 10A 이하에서도 용접이 가능한 극 정밀 직류 TIG 펄스 용접기에 관한 연구결과를 다룬다.