• 한국전산유체공학회지
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• 제12권1호
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• pp.16-21
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• 2007

This paper presents numerical results of fluid flows and mixing in a microfluidic device with AC electroosmotic flows (AC-EOF) around coplanar electrodes attached on the top and bottom walls. To obtain the flow and mixing characteristics, numerical computations are performed by using a commercial code, CFX10. Experiment was performed to confirm the generation of the drift velocity around the electrodes. It was found that near the coplanar electrodes 3-D complex flows are generated. The AC-electroosmotic flow on the electrodes plays an important role in mixing the liquid.

• ETRI Journal
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• 제18권1호
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• pp.1-14
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• 1996

We have experimentally observed and theoretically analyzed the gain dependent optimum repetition rates of a hybrid-type active and passive mode locked laser pulses in an erbium-doped fiber laser of the figure-of-eight geometry by utilizing a nonlinear amplifier loop mirror (NALM) as a saturable absorber and a directional-coupler type electro-optic modulator as an active mode locker. Transform-limited mode-locked pulses of about 10 ps width were obtained at repetition rates which correspond to harmonics of the cavity fundamental frequency and depend on the optical amplifier gain in the NALM.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.153-153
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• 2015

Application of the plasma is already highlighted as a new technology in the last few years. In these days, there are lots of attempt in various application with plasma in that it is known as an effective treatment to animal, plants, material and so on. Plasma in liquid, one of new plasma applications, has advantages in ability to treat bio-cell or solutions. For example, electro-surgery, water purification, radical generation and so on. Especially, plasma discharge in solutions is very useful technique and difficult to generate due to electrolysis, vaporization and something else. In this study, we have performed plasma discharge and checked sustainability of plasma in solution(saline 0.9%). And we have measured basic characteristics of plasma in liquid. Such as electrical energy and plasma density are calculated from discharging current and voltage. Also, its thermal energy is measured with IR camera.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.164-164
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• 2009

A multilayer piezoelectric transformer(MPT) for step-down voltage was made by ceramic stack process. And then, the characteristics of piezoelectric transformer, such as resonance frequency, matching impedance, electro-mechanical coupling coefficient, voltage gain, heat generation and efficiency, are analyzed. The piezoelectric transformer consists of a lead zirconate titanate ceramic with a high electromechanical quality factor. The piezoelectric transformer, with a multilayered construction in the thickness direction, was formed with dimensions 15mm long, 15mm wide and 5mm thick.

• 대한기계학회논문집B
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• 제23권8호
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• pp.1031-1039
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• 1999

Electrospraying comprises the generation of liquid droplets by applying a high voltage to the surface of a liquid. By monitoring the current and the flow rate it was possible to obtain a stable cone jet mode in a given condition. In this work the liquid contained NaCl particles resolved in distilled water. The NaCl particles increased concentration of the ionized solution and thus increased electrical conductivity of the liquid, which was inversely proportional to the flow rate in the cone jet mode. A number of sprayed droplets were sampled and dried enough, and then the size of NaCl particles were measured. The measured droplet diameter was a little larger than two theoretical diameters, Rayleigh diameter and mobility diameter.

• 전기전자학회논문지
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• 제15권2호
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• pp.129-133
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• 2011

A spread spectrum clock generation is an efficient way to reduce electro-magnetic interference (EMI) radiation in modern mixed signal chip systems. The proposed circuit generates the spread spectrum clock by directly injecting the modulation voltage into the voltage-controlled oscillator (VCO) current source for SATA II. The resulting 33KHz modulation profile has a Hersey-Kiss shape with a rounded peak. The chip has been fabricated using $0.18{\mu}m$ CMOS process and test results show that the proposed circuit achieves 0.509% (5090ppm) down spreading at 1.5GHz and peak power reduction of 10dB. The active chip area is 0.36mm ${\times}$ 0.49mm and the chip consumes 30mW power at 1.5GHz.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.40-43
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• 2003

An electric propulsion system integrated with the ship service distribution system offers the naval architect considerable flexibility, and often the choice of a more affordable ship to acquire and operate as compared to a segregated mechanical drive option. United States of America navy announced in 2000 that they selected the electric propulsion system on next generation warship. Specially there is excellent advantages in superconductivity motors which can have higher efficiency, less vibration and noise, smaller dimensions compared with the conventional motors. The 5 MW HTS motor for warship test of electric propulsion was developed and tested. Also it was contracted between AMSC and United States of America navy to develop a 36.5 MW HTS motor in 3 years since March 3, 2003. This paper deals with the technical development tendency of HTS motors in foreign countries as well as in domestic, and it is focused on the application of HIS motors to the electrical propulsion system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1041_1042
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• 2009

본 논문에서는 연료전지 태양광 복합발전시스템의 2가지 전력제어 알고리즘을 제안하고 각각의 성능을 비교 분석하였다. 태양광의 MPPT제어 위치에 따라 2가지 전력제어 알고리즘이 적용되었으며 각 알고리즘에 따른 MPPT성능, DC link 안정성과 출력전력 특성이 비교 분석되었으며 시뮬레이션 및 실험을 통해 타당성을 검증하였다.

• 전기학회논문지P
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• 제58권1호
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• pp.9-14
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• 2009

The modelling of PEMFC(Proton Exchange Membrane Fuel Cell) has been studied in many kinds of methods. But there are some limitations in application of the developed models to analyze transient phenomena of power systems. The PSCAD/EMTDC is very popular simulation tool in power system areas. To analyze power systems interconnected to PEMFCs, the PSCAD/EMTDC model of the PEMFCs is needed. In this paper, we developed a PSCAD/EMTDC model of PEMFC based on electro-chemical characteristic equations of PEMFC. Also, we performed simulations using the developed model in the PSCAD/EMTDC program and tested appropriateness of the proposed models. The simulations showed good results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.139-140
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• 2008

Cooling systems for electronic equipments are becoming more important. Cooling technologies using natural and forced convection are limited and operated in very low efficiency. A corona discharge is utilized as the driving mechanism for anair pump, which allows for airflow generation with low noise and no moving parts. However they do not enhance the flow rate and overcome the control mechanism of the pump. In this study a point-mesh type air pump, with a third electro de installed near the corona point, has been proposed and investigated by focusing on elevating the ionic wind velocity and power yield. As a result, the significantly enhanced ionic wind velocity and tremendously increased power yield can be obtained with the proposed air pump system.