• 제목/요약/키워드: semi-empirical model

검색결과 183건 처리시간 0.027초

Quantum Simulation Study on Performance Optimization of GaSb/InAs nanowire Tunneling FET

  • Hur, Ji-Hyun;Jeon, Sanghun
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제16권5호
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    • pp.630-634
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    • 2016
  • We report the computer aided design results for a GaSb/InAs broken-gap gate all around nanowire tunneling FET (TFET). In designing, the semi-empirical tight-binding (TB) method using $sp3d5s^*$ is used as band structure model to produce the bulk properties. The calculated band structure is cooperated with open boundary conditions (OBCs) and a three-dimensional $Schr{\ddot{o}}dinger$-Poisson solver to execute quantum transport simulators. We find an device configuration for the operation voltage of 0.3 V which exhibit desired low sub-threshold swing (< 60 mV/dec) by adopting receded gate configuration while maintaining the high current characteristic ($I_{ON}$ > $100 {\mu}A/{\mu}m$) that broken-gap TFETs normally have.

ESTIMATION OF LOCAL LIQUID FILM THICKNESS IN TWO-PHASE ANNULAR FLOW

  • Lee, Bo-An;Yun, Byong-Jo;Kim, Kyung-Youn;Kim, Sin
    • Nuclear Engineering and Technology
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    • 제44권1호
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    • pp.71-78
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    • 2012
  • In many semi-empirical analyses of flow boiling heat transfer, an annular flow is often assumed as a model flow and the local liquid film thickness is a key parameter in the analysis. This work considers a simple electrical conductance technique to estimate the local liquid film thickness in two-phase annular flows. In this approach, many electrodes are mounted flush with the inner wall of the pipe. Voltage differences between two neighboring electrodes for concentric annular flows with various liquid film thicknesses are obtained before the main experiments and logged in a look-up table. For an actual application in the annual flow, voltage differences of neighboring electrodes are measured and then corresponding local film thicknesses are determined by the interpolation of the look-up table. Even though the proposed technique is quite simple and straightforward, the numerical and static phantom experiments support its usefulness.

Design of a PIV objective maximizing the image signal-to-noise ratio

  • Chetelat Olivier;Kim Kyung Chun
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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    • pp.123-137
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    • 2001
  • PIV (particle image velocimetry) systems use a camera to take snapshots of particles carried by a fluid at some precise instants. Signal processing methods are then used to compute the flow velocity field. In this paper, the design of the camera objective (optics) is addressed. The optimization is done in order to maximize the signal-to-noise ratio of in-focus particles. Four different kinds of noise are considered: photon shot noise, thermal and read noise, background glow shot noise, and noise made by the other particles. A semi-empirical model for the lens aberrations of a two-doublet objective is first addressed, since further, it is shown that lens aberrations (low f-value $f_{\#}$) should be used instead of the Fraunhofer diffraction (high f-value) for the fitting of the particle image size with the pixel size. Other important conclusions of the paper include the expression of optimum values for the magnification M, for the exposure period $\tau$ and for the pixel size $\xi$.

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구동방법에 따른 TFT-LCD 화소 특성 시뮬레이션 (Simulations of TFT-LCD Pixel Characteristics with Different Driving Methods)

  • 흥성진;최종선;이신두
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 C
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    • pp.1603-1605
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    • 2002
  • TFT-LCD is widely used for flat panel display. The large-size TFT-LCD panel requires a high speed driving and various driving methods because of signal delay, which is responsible for the shading effects. In this work, the floating and double driving methods are applied to Pixel Design Array Simulation Tool(PDAST) and the pixel characteristics of TFT-LCD array is simulated. Also, we have implemented the semi-empirical TFT model to PDAST, which makes to obtain a more accurate pixel characteristics.

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Mutual Coupling Capacitance and Cross-talk in TFT-LCD

  • Yun, Young-Jun;Jung, Soon-Shin;Kim, Tae-Hyung;Roh, Won-Yeol;Choi, Jong-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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    • pp.71-72
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    • 2000
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the mutual coupling capacitances present in a pixel. The mutual coupling capacitance causes a pixel voltage error. In this study, semi-empirical model, which is adopted from VLSI interconnection capacitance calculations, is used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and arbitrary given image pattern, the root mean square (RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained this study can be utilized to design the larger area and finer image quality panel.

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Approach to Characterization of a Diode Type Corona Charger for Aerosol Size Measurement

  • Intra Panich;Tippayawong Nakorn
    • KIEE International Transactions on Electrophysics and Applications
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    • 제5C권5호
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    • pp.196-203
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    • 2005
  • A semi-empirical method to determine the electrostatic characteristics of a diode type corona aerosol charger based on ion current measurement and electrostatic charging theory was presented. Results from mathematical model were in agreement with those from experimental investigation of the charger. Current-voltage characteristics, $N_{i}t$ product and charge distribution against aerosol size were obtained. It was shown that the space charge was significant and must be taken into account at high ion number concentration and low flow rate. Additionally, significant particle loss was evident for particles smaller than 20 nm in diameter where their electrical mobility was high. Increase in charging efficiency may be achieved by introducing surrounding sheath flow and applying AC high voltage. Overall, the approach was found to be useful in characterizing the aerosol charger.

Hot electron에 의하여 노쇠화된 PMOSFET의 문턱전압과 유효 채널길이 모델링 (The Threshold Voltage and the Effective Channel Length Modeling of Degraded PMOSFET due to Hot Electron)

  • 홍성택;박종태
    • 전자공학회논문지A
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    • 제31A권8호
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    • pp.72-79
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    • 1994
  • In this paper semi empirical models are presented for the hot electron induced threshold voltage shift(${\Delta}V_{t}$) and effective channel shortening length (${\Delta}L_{H}$) in degraded PMOSFET. Trapped electron charges in gate oxide are calculated from the well known gate current model and ΔLS1HT is calculated by using trapped electron charges. (${\Delta}L_{H}$) is a function of gate stress voltage such as threshold voltage shift and degradation of drain current. From the correlation between (${\Delta}L_{H}$) has a logarithmic function of stress time. From the measured results, (${\Delta}V_{t}$) and (${\Delta}L_{H}$) are function of initial gate current and device channel length.

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TFT-LCD 특성에 미치는 Capacitive Cross-talk의 영향에 대한 시뮬레이션 (Simulations of Capacitive Cross-talk Effects on TFT-LCD Operational Characteristics)

  • 윤영준;정순신;김태형;최종선
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.557-560
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    • 1999
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the parasitic capacitive elements present in a pixel. The capacitive coupling of the data line signal onto the pixel causes a pixel voltage error. In this study semi-empirical capacitance model which is adopted from VLSI interconnection capacitance calculations was used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and given image pattern, the root mean square(RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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정지궤도위성 전장품의 열설계 검증을 위한 최적 열해석 모델링 연구 (A Study on Optimized Thermal Analysis Modeling for Thermal Design Verification of a Geostationary Satellite Electronic Equipment)

  • 전형열;양군호;김정훈
    • 대한기계학회논문집B
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    • 제29권4호
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    • pp.526-536
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    • 2005
  • A heat dissipation modeling method of EEE parts, or semi-empirical heat dissipation method, is developed for thermal design and analysis an electronic equipment of geostationary satellite. The power consumption measurement value of each functional breadboard is used for the heat dissipation modeling method. For the purpose of conduction heat transfer modeling of EEE parts, surface heat model using very thin ignorable thermal plates is developed instead of conventional lumped capacity nodes. The thermal plates are projected to the printed circuit board and can be modeled and modified easily by numerically preprocessing programs according to design changes. These modeling methods are applied to the thermal design and analysis of CTU (Command and Telemetry Unit) and verified by thermal cycling and vacuum tests.

암 생존자의 암 재활에 대한 개념분석 (Concept Analysis of Cancer Rehabilitation for Cancer Survivors)

  • 장희경;박연환
    • Perspectives in Nursing Science
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    • 제8권1호
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    • pp.1-9
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    • 2011
  • Purpose: The purpose of this study was to identify and define the concept of cancer rehabilitation in the lives of cancer survivors. Methods: A hybrid model of concept development was used to interface theoretical analaysis and empirical observation with a focus on definition. A comprehensive literature review and semi-structured interviews with five cancer survivors were completed. Results: The concept of cancer rehabilitation was found to be a route toward a positive experience having meaning in two dimensions: recovery of the activities of daily living and intrapersonal growth. Four attributes and ten indicators were defined. Conclusion: Cancer rehabilitation was defined as a positive process of change through recovery of the activities of daily living and intrapersonal growth. Therefore, oncology nurses can be encouraged to design, implement, and evaluate cancer rehabilitation nursing interventions with the results of this study. Further research needs to develop cancer rehabilitation measurements.

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