• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.173-178
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• 1996

The objective of this paper is to investigate the effect of AC field on the protoplast of plant cells. The results of investigation will be the basis for the development of etectric cell fusion device. For the experiment, we made the electrode and AC and DC pulse generator and observed the behavior of the protoplasts through the inverted microscope which is connected to the monitor and video recorder by the CCD camera. As a result, the numbers of rotating, moving and destructed protoplasts and viability of the protoplasts have close relation to the amplitude of AC field, while the rotation rate is closely related to the frequency of AC pulse.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.227-230
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• 2002

New polishing technique for small parts has been tried out using the principle of particle electromechanics. Common fine abrasives such as alumina, diamond, silicon carbide are dielectric materials which are polarized under an electric field, and a non-uniform electric field makes abrasive particles translate along the field line. Using this principle, We make abrasive particles aggregate in the vicinity of the micro tool which is fir the surface finishing of a small part without contact with it. The behavior of particles is optically measured, and the machined depth of glass is examined.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1989년도 추계학술발표회논문집
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• pp.9-12
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• 1989

ABSTRACT -- Recently, a method of magnetically-enhanced discharge columns is considered to increase the luminous efficacy of discharge lamps, which is based upon the face that the diffusion motion of charged particles in the discharge column strongly depends on the applied magnetic fields. This study investigates the effect of applied transverse magnetic fields on the light output of low-pressure Hg-Ar discharge. As a result, it is found that the electric field in the positive column increases according to the applied megnetic field, which causes an increase in the total light output. And this effect is much more pronounced upon the spectral line originating form the higher levels.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.874-879
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• 2004

The Korean high speed train runs at 300 km/h, ballast-flying phenomenon often happens by strong train-wind. It is important to consider the prevention of ballast-flying phenomenon, because the train under-body and fares or walker around a track might be damaged. In this study, Numerical analysis of the under-body flow field of a train and study of heighter-effect were conducted to decrease the speed of under-body. The shape of under-body was simplified for convenience of meshing and analysis. According to results of Taguchi's design by orthogonal arrays, a height of tie is dominant in the flow field, so if the heighter is installed on tie, the speed of under-body might be decreased. To apply the result of this study is useful to build a new high-speed-line might be expected.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권1호
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• pp.27-31
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• 2014

Magnetic fields (MF) generated both on board the vehicle and along the guideway provide levitation and propulsion forces. High speed maglev trains adopt electromagnet or superconducting magnet to realize levitation and propulsion functions. However, stray fields existing in passenger compartment and regions surrounding the vehicle and guideway have effect on passengers and environment. To investigate stray magnetic field effect, model of Transrapid and MLX are studied.

• 전기의세계
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• 제21권4호
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• pp.15-21
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• 1972

For the conventional DC machine, the armature MMF is negligible compared with field MMF except when the machine is under heavy load or transient conditions. During the motor starting or reversal, the transient armature current and corresponding MMF effect the flux density of each pole in the machine magnetic circuit. However, the circuit flux density is restored to normal values by the field winding MMF after the transient armature current dies in an electromagnetic DC motor. Permanent magnet servomotor have no field windings about the circuit poles to restore circuit flux density through the demagnetized part of each pole after the transient armature MMF dies, and portions of the magnetic circuit stay permanently demagnetized. Thus the problem of stabilizing a magnet pole piece under the influence of the transient armature current need attentions. This work present the recoil operation of the servomotor with PM poles in conjunctions with the influence of the armature reaction effect. The development of an analytical and quantatative study is presented for predicting the regime of the recoil operation under this condition.

• 한국초전도ㆍ저온공학회논문지
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• 제13권4호
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• pp.14-17
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• 2011

The evaluation of the electromechanical properties of HTS CC tapes is one of the foremost procedures to be done to ensure the applicability of superconducting wires to electric devices. A precise measurement of the stress and strain is important in deriving the mechanical properties under operating environment. Up to now, there is no standard test method yet for the electromechanical property evaluation of HTS tapes under self field and external magnetic field although there are already reports on the different devices used to evaluate these properties. Strain can be measured by adopting a strain gauge or a high resolution double extensometer. In this study, strain effect on $I_c$ in HTS CC tapes under magnetic fields was evaluated. Comparison of advantages and setback of strain measuring devices were discussed. In addition, a dual strain measurement system using both the SG and extensometer may be practical to lessen the burden in case one of the measuring devices does not work well.

• Journal of Magnetics
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• 제16권3호
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• pp.259-262
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• 2011

Compared to acupuncture, the pulsed magnetic field (PMF) stimulus is a useful tool for treatment of many physical conditions and health maintenance due to its advantages as a noninvasive and nontoxic medical treatment. The purpose of this study was to investigate the effect of PMF stimulus direction at PC9 on the alpha activity of electroencephalogram (EEG) and vascular aging calculated from photoplethysmograph (PPG). It can be concluded that the direction of PMF stimulus affects the increase of alpha activity of EEG and PPG, indicating the vascular stiffness and the sclerosis level of blood vessels weakly relevant to the direction of PMF stimulus.

• 전기전자학회논문지
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• 제19권4호
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• pp.514-519
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• 2015

본 논문에서는 이중 게이트 junctionless MOSFET 의 성능 최적화를 위하여 다중 게이트 형태를 적용하여 평가한다. 금속 게이트들 사이의 일함수가 서로 다르므로 다중 게이트 구조를 적용할 경우 금속게이트 길이에 따라 소스와 드레인 주변의 전위를 조절할 수 있다. 동작 전류와 누설 전류 그리고 동작 전압은 게이트 구조에 의해 조절이 가능하며 이로 인한 동작 특성 최적화가 가능하다. 본 연구에서는 반도체 소자 시뮬레이션을 통하여 junctionless MOSFET 의 최적화를 구현하고 분석하는 연구를 수행 한다.

• 전기전자학회논문지
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• 제17권2호
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• pp.129-134
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• 2013

For the conventional power metal-oxide semiconductor field-effect transistor (MOSFET) device structure, there exists a tradeoff relationship between specific on-resistance ($R_{ON.SP}$) and breakdown voltage ($V_{BR}$). In order to overcome the tradeoff relationship, a uniform super-junction (SJ) trench metal-oxide semiconductor field-effect transistor (TMOSFET) structure is studied and designed. The structure modeling considering doping concentrations is performed, and the distributions at breakdown voltages and the electric fields in a SJ TMOSFET are analyzed. The simulations are successfully optimized by the using of the SILVACO TCAD 2D device simulator, Atlas. In this paper, the specific on-resistance of the SJ TMOSFET is successfully obtained 0.96 $m{\Omega}{\cdot}cm^2$, which is of lesser value than the required one of 1.2 $m{\Omega}{\cdot}cm^2$ at the class of 100 V and 100 A for BLDC motor.