• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.121.1-121.1
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• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

• 한국식품조리과학회지
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• 제10권4호
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• pp.357-362
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• 1994

Beef loaves(5${\times}5{\times}$5cm) were cooked by conventional moist-heat and by various levels of microwaves. The mean internal temperature of the meats cooked by low power microwaves for 5~15 min were not significantly different from the conventionally boiled meats for 30 min. When cooking was made by microwaves at low level for 5~10 min, or at high level for 2 min and additional heating at low power level for 5min, the percent cooking loss were comparable with the samples cooked conventionally for 20~40 min. General proteolytic activity determined with azocoll indicated that enzyme activity decreased as internal temperature increased(r=-0.5779, p<0.05), and maximum activity occured at meats conventionally moist-heated for 10 min and by low power microwave for 5 min. Sensory scores for tenderness were high at conventional moist-heat for 30 min, for 20 min, microwave cooked at thatwing power for 10 min and at low power level for 10 min, in descending order. There were no significant differences in the thiamin content of meats after various treatments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1275-1277
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• 1995

We designed and constructed an extremly high power s-band traveling wave resonator for the test of high power microwave components using 80MW pulsed klystron with $4{\mu}s$ pulse width. The 10dB directional coupler for the input power coupling was used, and the ring consists of phase shifter, tuner, H-band, and other microwave components. The designed total electrical length of the system is 10 times of the waveguide wavelength, ${\lambda}_g$=15.3cm, and the measured total insertion loss is 0.15dB. The low power test measurment showed the power multiplication of 14.69. The design goal is to achieve the peak power of 300MW, pulse width $4{\mu}s$ with 30 pulse repetition rate. In this article we discuss the treveling wave resonant ring constructed at the PAL laboratory together with the test results.

• ETRI Journal
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• 제35권3호
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• pp.546-549
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• 2013

A Ka-band 6-W high power microwave monolithic integrated circuit amplifier for use in a very small aperture terminal system requiring high linearity is designed and fabricated using commercial 0.15-${\mu}m$ GaAs pHEMT technology. This three-stage amplifier, with a chip size of 22.1 $mm^2$ can achieve a saturated output power of 6 W with a 21% power-added efficiency and 15-dB small signal gain over a frequency range of 28.5 GHz to 30.5 GHz. To obtain high linearity, the amplifier employs a class-A bias and demonstrates an output third-order intercept point of greater than 43.5 dBm over the above-mentioned frequency range.

• 전력전자학회논문지
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• 제22권5호
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• pp.457-462
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• 2017

This paper proposes a digital power control of the LLC resonant half-bridge inverter for high power microwave oven application. Conventional half-bridge inverter for driving a microwave oven uses a hardware-based power control method which varies the frequency according to the AC source voltage. In this case, it is difficult to control the output power according to the variation of the load status of magnetron. The proposed power control consists of an instantaneous current generator and a current controller. Instantaneous current generator makes an instantaneous current reference from power command using input voltage information. Current controller controls input current which has an information of status of magnetron. The proposed power control does not require any compensation algorithm for the change of the load status of the magnetron and change of input voltage. The validity of the proposed method for the control of the change of input voltage and frequency is verified by both simulation and experiment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.287-287
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• 2009

The characteristics of slow wave structure employed for backward wave oscillators expected to be a high power microwave source are studied analytically and experimentary. The slow wave structure is a sinusoidally corrugated wall waveguide The dispersion relationn and transmitted characteristics for microwaves are measured in the air. There exist literatures on high efficiency of enhanced radiation from backward wave oscillators involving plasma studied experimentally.

• ETRI Journal
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• 제36권3호
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• pp.498-501
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• 2014

A C-band 50 W high-power microwave monolithic integrated circuit amplifier for use in a phased-array radar system was designed and fabricated using commercial $0.25{\mu}m$ AlGaN/GaN technology. This two-stage amplifier can achieve a saturated output power of 50 W with higher than 35% power-added efficiency and 22 dB small-signal gain over a frequency range of 5.5 GHz to 6.2 GHz. With a compact $14.82mm^2$ chip area, an output power density of $3.2W/mm^2$ is demonstrated.

• 한국식품조리과학회지
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• 제11권2호
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• pp.98-103
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• 1995

The effect of blanching time, blanching water and power settings of microwave oven on the minerals retention in spinach and broccoli were investigated. The vegetables were blanched for 60, 120 and 180 sec, with water 0ml, 50ml and 100ml every 100 g of raw material at two different power settings (700w, 400w). The retention of minerals(Ca,K,Mg,Cu,Fe,Na,p) in spinach and broccoli were higher at the 400w power than 700w power level, regardless of blanching time. At the high power, the retention of minerals in spinach and broccoli were reduced remarkably as the blanching time increased. The reason for this is that the increasing power level results in greater water coming ou from the vegetable. Also, minerals in vegetable as coming out with this water loss in proportion to the blanching time.

• 한국진공학회지
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• 제17권5호
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• pp.408-418
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• 2008

본 논문에서는 집속이온빔의 플라즈마원을 위한 간단한 직육면체형태의 공진 공동을 설계하고 특성연구를 수행하였다. 공진에 최적인 공동 구조는 HFSS(High Frequency Structure Simulator)를 이용한 전기장 분포를 통해 구체적으로 계산하였다. 공진 공동은 내부 석영관 및 플라즈마 등의 유전체의 영향을 받기 때문에 공동의 한축 길이를 변화시킬 수 있는 구조로 설계되었다. 실험적으로 관찰되는 마이크로웨이브 방전시작전압을 통해 방전에 최적인 공동 길이를 측정하여 HFSS 계산된 값과 비교하였다. 공동은 석영관으로 인한 내부 유효유전율의 변화에 의해 석영관을 고려하지 않았던 길이에 비해 10cm가 감소된 길이에서 최적화됨을 공통적으로 확인할 수 있었다. 또한 압력변화에 따른 방전시작전압은 Paschen Curve와 유사한 결과를 나타내었다. 방전이 발생한 후에는 입력전력에 따라 플라즈마 밀도가 증가하였고 플라즈마의 영향으로 감소한 유효유전율에 의해 10cm가 증가한 길이에서 최적화가 되었다. 하지만 300W이상의 높은 입력 전력에서는 마이크로웨이브가 투과할 수 없는 고밀도 플라즈마 경계층(cut off layer)이 확장하여 더 이상 공동길이 조절을 통한 공동 최적화가 불가능함을 확인하였다. 따라서 고밀도 플라즈마를 만들기 위한 마이크로웨이브 공동의 정확한 설계를 위해 마이크로웨이브가 통과할 수 없는 고밀도 플라즈마 영역을 도체로 가정하고 그 외의 저밀도 플라즈마 영역을 밀도에 고유한 특정 유전율을 가지는 유전체로 설정하여 공동 내부의 전기장 분포를 해석하는 과정이 꼭 필요하다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.251-251
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• 2006