• 제목/요약/키워드: Field effect

검색결과 12,296건 처리시간 0.038초

실리콘 나노 박막의 열-전계 방출효과를 이용한 분자 질량분석 (Thermo-Field emission in silicon nanomembrane ion detector for mass spectrometry)

  • 박종후
    • 한국응용과학기술학회지
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    • 제30권4호
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    • pp.586-591
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    • 2013
  • 본 연구에서는 가속된 이온이 전기장이 걸려있는 freestanding 단결정 실리콘 나노 박막에 충돌했을 때 발생하는 열-전계 전자 방출 특성을 여러 전계 및 열적 조건 아래 체계적으로 분석하였다. 이온 충돌에 의한 열-전계 전자 방출은 쇼트키 효과 (schottky effect)의 선형영역의 특성에 의해 예측된 바와 같이 전계의 세기가 증가할수록 선형적으로 증가했으며, 이온 충돌에 의해 발생하는 열에너지의 제곱에 비례하는 특성을 보여주었다. 이러한 특성들은 실리콘 나노 박막의 질량 분석기용 이온 검출기로의 사용 가능성을 보여준다.

자기장 분포가 확산화염의 연소특성에 미치는 영향: 자기장 On/Off 주기와 Duty Ratio의 역할 (The Influence of Magnetic Field on Diffusion Flames: Role of Magnetic Field On/Off Frequency and Duty Ratio)

  • 이원남;배승만
    • 한국연소학회지
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    • 제17권1호
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    • pp.58-65
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    • 2012
  • The influence of magnetic field on propane and acetylene diffusion flames have been experimentally investigated using an electromagnetic system. Periodically induced magnetic field having various frequencies and duty ratios was established in square wave form. The maximum intensity and gradient of magnetic field were 1.3 T and 0.27 T/mm, respectively. The width of a propane flame was reduced up to 4.5% and the brightness was enhanced up to 25% when the magnetic field was induced. The soot emission from an acetylene flame was ceased when magnetic field was induced. The alteration of flow field, which is due to the paramagnetic characteristics of oxygen molecule, is most likely to be responsible for the change in flame size and brightness. The effect of magnetic field on diffusion flames, which competes with the gravitational effect, was more apparent from a smaller size flame. The magnetic field effect, therefore, could be important under microgravity conditions. Since the time required to alter the flow field must be finite, the magnetic field effect is likely to be less significant for a periodically oscillating magnetic field at a high frequency or having a small duty ratio.

Analysis of Magnetic Field Application Effect on Fault Current Limiting Characteristics of a Flux-lock Type SFCL

  • Lim, Sung-Hun
    • Transactions on Electrical and Electronic Materials
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    • 제9권6호
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    • pp.255-259
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    • 2008
  • The magnetic field application effect on resistance of a high-$T_c$ superconducting (HTSC) element comprising a flux-lock type superconducting fault current limiter (SFCL) was investigated. The YBCO thin film, which was etched into a meander line using a lithography, was used as a current limiting element of the flux-lock type SFCL. To increase the magnetic field applied into HTSC element, the capacitor was connected in series with a solenoid-type magnetic field coil installed in the third winding of the flux-lock type SFCL. There was no magnetic field application effect on the resistance of HTSC element despite the application of larger magnetic field into the HTSC element when a fault happened. The resistance of HTSC element, on the contrary, started to decrease at the point of four periods from a fault instant although the amplitude of the applied magnetic field increased.

Investigation of Junction-less Tunneling Field Effect Transistor (JL-TFET) with Floating Gate

  • Ali, Asif;Seo, Dongsun;Cho, Il Hwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제17권1호
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    • pp.156-161
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    • 2017
  • This work presents a novel structure for junction-less tunneling field effect transistor (JL-TFET) with a floating gate over the source region. Introduction of floating gate instead of fixed metal gate removes the limitation of fabrication process suitability. The proposed device is based on a heavily n-type-doped Si-channel junction-less field effect transistor (JLFET). A floating gate over source region and a control-gate with optimized metal work-function over channel region is used to make device work like a tunnel field effect transistor (TFET). The proposed device has exhibited excellent ID-VGS characteristics, ION/IOFF ratio, a point subthreshold slope (SS), and average SS for optimized device parameters. Electron charge stored in floating gate, isolation oxide layer and body doping concentration are optimized. The proposed JL-TFET can be a promising candidate for switching performances.

핫 캐리어에 의한 피-모스 트랜지스터의 채널에서 이동도의 열화 특성 (Degradation Characteristics of Mobility in Channel of P-MOSFET's by Hot Carriers)

  • 이용재
    • 한국전기전자재료학회논문지
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    • 제11권1호
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    • pp.26-32
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    • 1998
  • We have studied how the characteristics degradation between effective mobility and field effect mobility of gate channel in p-MOSFET's affects the gate channel length being follow by increased stress time and increased drain-source voltage stress. The experimental results between effective and field-effect mobility were analyzed that the measurement data are identical at the point of minimum slope in threshold voltage, the other part is different, that is, the effective mobility it the faster than the field-effect mobility. Also, It was found that the effective and field-effect mobility. Also, It was found that the effective and field-effect mobility of p-MOSFET's with short channel are increased by decreased channel length, increased stress time and increased drain-source voltage stress.

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BiPbSrCaCuO 초전도 벌크의 Magnetic Suspension (Magnetic Suspension Effect of BiPbSrCaCuO Superconducting Bulk)

  • 이상헌
    • 한국전기전자재료학회논문지
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    • 제17권5호
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    • pp.545-551
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    • 2004
  • Magnetic suspension effect has been studied by using superconductor of BiPbSrCaCuO ceramics containing Ag$_2$O. Magnetic flux measurements of a toroidal magnet revealed a concave shaped field distribution with a null field along the axis of the torus at the point where the field reversed. The suspension effect was observed only for the Ag$_2$O doped and field cooled sample which is attributed to the enhanced flux pinning due to the field cooled condition. It has been cleared that Ag$_2$O acts as pinning center which plays an important role to the magnetic suspension effect. Magnetic repulsive force which affects a superconductor located in magnetic flux from toroidal magnet has been investigated. It has been concluded that the magnetic suspension effect arises from the interaction between the pinning effect and the diamagnetic effect.

Field-effect Ion-transport Devices with Carbon Nanotube Channels: Schematics and Simulations

  • Kwon Oh Kuen;Kwon Jun Sik;Hwang Ho Jung;Kang Jeong Won
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2004년도 학술대회지
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    • pp.787-791
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    • 2004
  • We investigated field-effect ion-transport devices based on carbon nanotubes by using classical molecular dynamics simulations under applied external force fields, and we present model schematics that car be applied to the nanoscale data storage devices and unipolar ionic field-effect transistors. As the applied external force field is increased, potassium ions rapidly flow through the nanochannel. Under low external force fields, ther nal fluctuations of the nanochannels affect tunneling of the potassium ions whereas the effects of thermal fluctuations are negligible under high external force fields. Since the electric current conductivity increases when potassium ions are inserted into fullerenes or carbon nanotubes, the field effect due to the gate, which can modify the position of the potassium ions, changes the tunneling current between the drain and the source.

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Field terminator를 이용한 CMA 제작에 관한 연구 (The Study on CMA using field terminator)

  • 이충만;성면창;권순남;정광호
    • 한국진공학회지
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    • 제5권4호
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    • pp.278-283
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    • 1996
  • Field terminator를 이용하여 singl path cylindrical mirror analyser를 제작하였다. 먼저 컴퓨터 모의실험을 바탕으로 CMA의 원통형 전극양단에서 fringing field effect를 최소로 하여 log-scale의 등전위면을 그대로 유지하는 terminator의 전압비와 위치 등을 구하였다. 계산된 전압을 직렬로 연결된 금속산화물저항으로 만든 voltage divider로 field terminator에 직접 인가하여 CMA의 fringing field effect를 줄이는 방법으로 개발하였다. 이 방법으로 제작된 CMA의 분해능이 $\Delta$E/E=0.4% 이상임을 확인하였다.

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상시하중상태에서 박벽의 보강효과에 대한 연구 (Reinforcing Effect of Thin-wall at Serviceability Condition)

  • 김두환;윤성수;박진선
    • 한국농공학회논문집
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    • 제52권2호
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    • pp.11-17
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    • 2010
  • For the reasonable analysis of design problems for agricultural facilities, considered the reinforcing effect of thin-wall. The most of agricultural structure is constructed small scale and have many purposes. Thus it has been designed temporary rather than permanent structure, and has relatively large slenderness ratio, small section and semi-rigid condition. Therefore many agricultural facilities are consist of relatively strong frame with weak wall at the viewpoint of stiffness and have not been reflected in the design. But the tension field influences to collapse of structure have already known. Therefore, we need quantification the effect of tension field at structural analysis. In this study, present the method of quantification the effect of tension field that came out thin-plate surrounded by high stiffness frame. The numerical results show that the effect of tension field effect for thin-wall is about 5% of the sectional area of frame in study agricultural facilities.

Effect of Stator Slotting in the Magnetic Field Distribution of Linear Brushless Permanent Magnet Motor

  • Chung, Myung-Jin;Lee, M.G;Lee, S.Q;Gweon, Dae-Gab
    • Journal of Magnetics
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    • 제6권3호
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    • pp.101-107
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    • 2001
  • A model to describe the effect of stator slotting in the airgap region of a linear brushless permanent magnet motor (LBLPMM) is proposed for analytical prediction of magnetic field distribution. It is a two-dimensional model based on superposition of the effect of stator slotting and main field due to permanent magnet (PM) without stator slotting. The effect of stator slotting is expressed in form of a generalized equation, which is obtained by numerical analysis and is a function of motor geometric parameters, so the proposed model effectively accounts for the effect of stator slotting in the airgap field distribution according to change of motor geometry or relative motion of stator and armature. Results of prediction from the proposed model are compared with corresponding finite element analysis.

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