• 제목/요약/키워드: local electric field

검색결과 103건 처리시간 0.021초

Non-local impact ionization 현상해석을 위한 local model 개발 (Implementation of local model for non-local impact ionization)

  • 염기수
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 1999년도 춘계종합학술대회
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    • pp.385-388
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    • 1999
  • Non-local impact ionization 현상의 해석에 사용될 수 있는 새로운 local model이 제시되었다. 새로운 모델은 임의의 점에서 가상의 선형 전기장과 path integral로 계산되는 유효전기장의 값을 이용한다. 이 모델은 불순물 농도, 전자 및 홀 농도, 전기장의 기울기 둥의 local 변수만을 이용함으로써 기존의 drift-diffusion 소자 시뮬레이터에 쉽게 적용될 수 있다. 결과를 Monte Carlo 시뮬레이션과 비교하여 새로운 모델이 non-local 현상을 잘 설명하는 것을 확인할 수 있었다.

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절연유의 도전전류와 직류절연파괴특성에 관한 연구 (A study on conduction current and D.C. breakdown characteristics in dielectric liquids)

  • 서국철
    • 전기의세계
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    • 제30권4호
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    • pp.231-236
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    • 1981
  • It has been known that D.C. breakdown Voltage is lower than A.C. breakdown Voltage in insulatingoil, but there are still many unvivid points at electric conduction in breakdown or under of high electric field. This study measured the electric current-electric field characteristics (I-E characteristics) and the breakdown Voltage under of D.C. electric field of insulating oil using the system of electrodes that are near the Uniform electric field with a result. I can study, electric conduction in area of high electric field depends upon the Schottky effect. The liquidity of breakdown electric field takes place by the local concentration of electric field. The longer gap is and the more electric current is the more breakdown Voltage decreased. There are not almost the change of electric current-electric field characteristics by materials of electrode.

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Atomic Force Microscopy을 이용한 4H-SiC의 Local Oxidation (Local oxidation of 4H-SiC using an atomic force microscopy)

  • 조영득;방욱;김상철;김남균;구상모
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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    • pp.79-80
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    • 2009
  • The local oxidation using an atomic force microscopy (AFM) is useful for Si-base fabrication of nanoscale structures and devices. SiC is a wide band-gap material that has advantages such as high-power, high-temperature and high-frequency in applications, and among several SiC poly types, 4H-SiC is the most attractive poly type due to the high electron mobility. However, the AFM local oxidation of 4H-SiC for fabrication is still difficult, mainly due to the physical hardness and chemical inactivity of SiC. In this paper, we investigated the local oxidation of 4H-SiC surface using an AFM. We fabricated oxide patterns using a contact mode AFM with a Pt/Ir-coated Si tip (N-type, $0.01{\sim}0.025\;{\Omega}cm$) at room temperature, and the relative humidity ranged from 40 to 50%. The height of the fabricated oxide pattern ($1{\sim}3\;nm$) on SiC is similar to that of typically obtained on Si ($10^{15}{\sim}10^{17}\;cm^{-3}$). We perform the 2-D simulation to further analyze the electric field between the tip and the surface. Whereas the simulated electric field on Si surface is constant ($5\;{\times}\;10^7\;V/m$), the electric field on SiC surface increases with increasing the doping concentration from ${\sim}10^{15}$ to ${\sim}10^{17}\;cm^{-3}$. We demonstrated that a specific electric field ($4\;{\times}\;10^7\;V/m$) and a doping concentration (${\sim}10^{17}\;cm^{-3}$) is sufficient to switch on/off the growth of the local oxide on SiC.

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유한요소법을 이용한 쌍극자 공간전하 방전분산형 피뢰침 정전유도구체의 국부전계 해석 (Local Electric Field Analysis for Evaluation of Charge Transfer System Using Sequential Sub-window Techniq)

  • 정용기;곽희로;이준호;박일한
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 C
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    • pp.1650-1652
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    • 2003
  • In this study, in order to increase electric field intensify near a lightning rod a floating conductor is adopted. If a floating conductor is located near the lightning rod, the positive and negative charges are equally induced on the lightning rod and the floating conductor, and the local electric field intensity near them increases. This increase of electric field intensity can ignite easily the ionization process of the surrounding air and the corona phenomenon begins there. It occurs before the usual lightning process begins on the top of the conventional rod. The charges of the ground or some buildings are omitted during the corona process through the floating conductor. Therefore, the probability of the main lightning on the conventional rod can be reduced.

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전기장의 국소변화에 따른 전기삼투 유동 및 혼합 특성해석 (A STUDY ON CHARACTERISTICS OF EECTRO-OSMOTIC FLOWS UNDER THE LOCAL VARIATION OF THE ELECTRIC FIELD)

  • 허형석;정종현;서용권
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2005년도 추계 학술대회논문집
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    • pp.27-30
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    • 2005
  • In a microfluidic chips pressure driven flow or electro-osmotic flow has been usually employed to deliver bio-samples. Flow in the chips is usually slow and the mixing performance is poor. A micro-mixer with a rapid mixing is important for practical applications. In this study a newly designed and electro-osmotic driven micro-mixer is proposed. This design is comprised of a channel and a series of metal electrodes periodically attached on the side surface. In this configuration electro-osmotic flows and the stirring effects are simulated three-dimensionally using a commercial code, CFD-ACE. Focus is given the effect on the electro-osmotic flow characteristics under the local variation of the electric field.

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정전효과가 있는 가열 수평웨이퍼로의 입자침착에 관한 해석 (Analysis on particle deposition onto a heated, horizontal free-standing wafer with electrostatic effect)

  • 유경훈;오명도;명현국
    • 대한기계학회논문집B
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    • 제21권10호
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    • pp.1284-1293
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    • 1997
  • The electrostatic effect on particle deposition onto a heated, Horizontal free-standing wafer surface was investigated numerically. The deposition mechanisms considered were convection, Brownian and turbulent diffusion, sedimentation, thermophoresis and electrostatic force. The electric charge on particle needed to calculate the electrostatic migration velocity induced by the local electric field was assumed to be the Boltzmann equilibrium charge. The electrostatic forces acted upon the particle included the Coulombic, image, dielectrophoretic and dipole-dipole forces based on the assumption that the particle and wafer surface are conducting. The electric potential distribution needed to calculate the local electric field around the wafer was calculated from the Laplace equation. The averaged and local deposition velocities were obtained for a temperature difference of 0-10 K and an applied voltage of 0-1000 v.The numerical results were then compared with those of the present suggested approximate model and the available experimental data. The comparison showed relatively good agreement between them.

Field Weakening Control of a PM Electric Variable Transmission for HEV

  • Cheng, Yuan;Bouscayrol, Alain;Trigui, Rochdi;Espanet, Christophe;Cui, Shumei
    • Journal of Electrical Engineering and Technology
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    • 제8권5호
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    • pp.1096-1106
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    • 2013
  • This paper presents the control of a Permanent Magnet Electric Variable Transmission (PM-EVT) for Hybrid Electric Vehicles (HEVs). Consisting of two electric machines, the EVT realizes the power split function in an electromagnetic way rather than in a mechanical way. A specific PM-EVT has been designed for Toyota Prius II. The control scheme of the entire vehicle is deduced using the Energetic Macroscopic Representation methodology. The energy management strategy yields local control references. A specific attention is paid for the field weakening for wide speed range. Simulation results are provided to illustrate the EVT modeling and control.

Cavity and Interface effect of PI-Film on Charge Accumulation and PD Activity under Bipolar Pulse Voltage

  • Akram, Shakeel;Wu, Guangning;Gao, GuoQiang;Liu, Yang
    • Journal of Electrical Engineering and Technology
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    • 제10권5호
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    • pp.2089-2098
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    • 2015
  • With the continuous development in insulation of electrical equipment design, the reliability of the system has been enhanced. However, in the manufacturing process and during operation under continues stresses introduce local defects, such as voids between interfaces that can responsible to occurrence of partial discharge (PD), electric field distortion and accumulation of charges. These defects may lead to localize corrosion and material degradation of insulation system, and a serious threat to the equipment. A model of three layers of PI film with air gap is presented to understand the influence of interface and voids on exploitation conditions such as strong electrical field, PD activity and charge movement. The analytical analysis, and experimental results are good agreement and show that the lose contact between interfaces accumulate more residual charges and in consequences increase the electric field intensity and accelerates internal discharges. These residual charges are trapped charges, injected by the electrodes has often same polarity, so the electric field in cavities increases significantly and thus partial discharge inception voltage (PDIV) decreases. Contrary, number of PD discharge quantity increases due to interface. Interfacial polarization effect has opposite impact on electric field and PDIV as compare to void.

국소장이 원자계에 미치는 영향에 대한 이론 II: 이준위 원자계에서의 거시 양자 Langevin 방정식의 유도 (Effect of local field on atomic systems II : Derivation of macroscopic quantum Langevin equations in two-level systems)

  • 안성혁
    • 한국광학회지
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    • 제14권1호
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    • pp.103-106
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    • 2003
  • 쌍극자들로 이루어진 이준위계의 해밀토니안이 주어질 때 이 계가 만족시키는 미시적인 양자 Langevin방정식을 유도하고, 이 방정식을 거시적인 구간 내에서 평균 함으로써 거시 양자 Langevin방정식을 유도하고 국소장 효과가 양자적으로 어떻게 표현되는 지를 살펴본다.

마이크로 채널 내 국소적 전위 인가에 따른 전기삼투 유동 및 혼합 특성에 대한 수치해석적 연구 (A Numerical Study on Electro-osmotic Flow and Stirring Characteristics in a Microchannel with Local Adjustment of Electric Potential)

  • 서용권;허형석
    • 한국가시화정보학회지
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    • 제4권1호
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    • pp.31-40
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    • 2006
  • In this study a newly designed electro-osmotic micro-mixer is proposed. This study is composed of a channel and metal electrodes attached locally on the side wall surface ultimately to control the mixing effect. To obtain the flow patterns, numerical computation was performed by using a commercial code, CFD-ACE. The fluid-flow solutions are the cast into studying the characteristics of stirring in terms of the mixing index. It was shown that the local control of the electric potential can indeed contribute to the enhancement of mixing effect.

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