• 제목/요약/키워드: current-voltage curve

검색결과 303건 처리시간 0.032초

Optimal Power Flow of DC-Grid Based on Improved PSO Algorithm

  • Liu, Xianzheng;Wang, Xingcheng;Wen, Jialiang
    • Journal of Electrical Engineering and Technology
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    • 제12권4호
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    • pp.1586-1592
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    • 2017
  • Voltage sourced converter (VSC) based direct-current (DC) grid has the ability to control power flow flexibly and securely, thus it has become one of the most valid approaches in aspect of large-scale renewable power generation, oceanic island power supply and new urban grid construction. To solve the optimal power flow (OPF) problem in DC grid, an adaptive particle swarm optimization (PSO) algorithm based on fuzzy control theory is proposed in this paper, and the optimal operation considering both power loss and voltage quality is realized. Firstly, the fuzzy membership curve is used to transform two objectives into one, the fitness value of latest step is introduced as input of fuzzy controller to adjust the controlling parameters of PSO dynamically. The proposed strategy was applied in solving the power flow issue in six terminals DC grid model, and corresponding results are presented to verify the effectiveness and feasibility of proposed algorithm.

급속 건식 열산화 방법에 의한 초박막 SiO2의 성장과 특성 (Growth and Properties of Ultra-thin SiO2 Films by Rapid Thermal Dry Oxidation Technique)

  • 정상현;김광호;김용성;이수홍
    • 한국전기전자재료학회논문지
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    • 제17권1호
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    • pp.21-26
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    • 2004
  • Ultra-thin silicon dioxides were grown on p-type(100) oriented silicon employing rapid thermal dry oxidation technique at the temperature range of 850∼1050 $^{\circ}C$. The growth rate of the ultra-thin film was fitted well with tile model which was proposed recently by da Silva & Stosic. The capacitance-voltage, current-voltage, characteristics were used to study the electrical properties of these thin oxides. The minimum interface state density around the midgap of the MOS capacitor having oxide thickness of 111.6 $\AA$ derived from the C-V curve was ranged from 6 to 10${\times}$10$^{10}$ /$\textrm{cm}^2$eV.

A Magnetic Hysteresis Curve Tracer for Rare Earth

  • Rhee, J.R.
    • Journal of Magnetics
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    • 제1권2호
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    • pp.94-100
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    • 1996
  • A hysteresis loop tracer using a pulsed high magnetic field of 113.4 kOe, which is suitable for rare earth based permanent magnets, is constructed. The high pulsed magnetic field is generated by discharging a large capacitance charge (5 mF) with a voltage of 600 V into an air solenoid with the inner diameter of 14 mm, outer diameter of 36 mm and the lingth of 34 mm. A computer simulation method is used for the construction of an electromagnet to optimize the many parameters such as the discharge current, generated pulsed magnetic field intensity, thermal dissipation, capacitance, charged voltage, period of damping oscillation and solenoid geometry. By using the hysteresis loop tracer constructed in this work, we are able to measure hystersis loops of several rare earth based permanent magnets with large values of the remanent magnetization, coercvity and energy product.

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다공질 실리콘의 유기가스 검지 특성 (Sensing Properties of Porous Silicon Layer for Organic Vapors)

  • 김성진;이상훈;최복길
    • 한국전기전자재료학회논문지
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    • 제15권11호
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    • pp.963-968
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    • 2002
  • In this work, porous silicon (PS) layer is investigated as a sensing material to detect organic vapors such as ethanol (called alcohol), methanol, and acetone in low concentrations. To do this, PS sensors were fabricated. They have a membrane structure and comb-type electrodes were used to detect the change of electrical resistance effectively. PS layer on Si substrates was formed by anodization in HF solution of 25%. From fabricated sensors, current-voltage (Ⅰ-Ⅴ) curves were measured for gases evaporated from 0.1 to 0.5% organic solution concentrations at 36$\^{C}$. As the result, all curves showed rectifying behavior due to a diode structure between Si and the PS layer. The conductance of most sensors increased largely at high voltage of 5V, but the built-in potential on the measured Ⅰ-Ⅴ curve was lowered inversely by the adsorption effect of the organic vapors with high dipole moment.

붕규산염 유리를 절연층으로 도포한 정전척의 제조 (Fabrication of Electrostatic Chucks Using Borosilicate Glass Coating as an Insulating Layer)

  • 방재철;이지형
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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    • pp.390-393
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    • 2001
  • This study demonstrated the feasibility of tape casting method to fabricate soda borosilicate glass-coated stainless steel electrostatic chucks(ESC) for low temperature semiconductor processes. The glass coatings on the stainless steel substrates ranged from $100{\mu}m$ to $150{\mu}m$ thick. The adhesion of the glass coatings was found to be excellent such that it was able to withstand moderate impact tests and temperature cycling to over $300^{\circ}C$ without cracking and delamination. The electrostatic clamping pressure generally followed the theoretical voltage-squared curve except at elevated temperatures and higher applied voltages when deviations were observed to occur. The deviation is due to increased leakage current at higher temperature and applied voltage as the electrical resistivity drops.

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유기 금속 할라이드 페로브스카이트에서 이온 이동 (Ion Migration in Organic Metal Halide Perovskites)

  • 오일환
    • 전기화학회지
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    • 제21권2호
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    • pp.21-27
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    • 2018
  • 본 총설에서는 최근 전세계적으로 각광 받고 있는 유기 금속 할라이드 페로브스카이트 소재에서 일어나는 이온 이동 현상에 대한 최신 연구에 대해 정리하였다. 페로브스카이트 물질 조성, 인가전압에 따라 다른 결과들이 보고되었지만, 실제 태양전지 작동 조건에서 iodide 가 이동하는 것으로 보이며, 때로는 methylammonium의 이동도 관찰된다. 페로브스카이트는 상온에서 전자와 이온이 동시에 이동하는 이른바 mixed conductor이고, 이는 페로브스카이트 태양전지 전류-전압곡선의 hysteresis, 장시간 작동에 따른 성능 저하 등에 지대한 영향을 미친다.

Au 전극과 pentacene 박막 계면의 contact resistance 측정 (Extraction of Contact Resistance in Interface Between Au Electrode and Pentacene Thin Film)

  • 정보철;류기성;김용규;송정근
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2006년도 하계종합학술대회
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    • pp.481-482
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    • 2006
  • We fabricated pentacene organic thin film transistor with good uniformity. And we extracted contact resistance in organic thin film transistors from the plot of the inverse of drain current versus channel length by extrapolating the curve to a channel length of zero, and multiplying by drain-source voltage. Extracted contact resistance is about $70K{\Omega}$ at gate-drain voltage of -20 V

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IGBT의 SPICE 파라미터 추출 (SPICE Parameter Extraction for the IGBT)

  • 김한수;조영호;최성동;최연익;한민구
    • 대한전기학회논문지
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    • 제43권4호
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    • pp.607-612
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    • 1994
  • The static and dynamic model of IGBT for the SPICE simulation has been successfully developed. The various circuit model parameters are extracted from the I-V and C-V characteristics of IGBT and implemented into our model. The static model of IGBT consists of the MOSFET, bipolar transistor and series resistance. The parameters to be extracted are the threshold voltage of MOSFET, current gain $\beta$ of bipolar transistor, and the series resistance. They can be extracted from the measured I-V characteristics curve. The C-V characteristics between the terminals are very important parameters to determine the turn-on and turn-off waveform. Especially, voltage dependent capacitance are polynomially approximated to obtain the exact turn-on and turn-off waveforms. The SPICE simulation results employing new model agree well with the experimental values.

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붕규산염 유리를 절연층으로 도포한 정전척의 제조 (Fabrication of Electrostatic Chucks Using Borosilicate Glass Coating as an Insulating Layer)

  • 방재철;이지형
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
    • /
    • pp.390-393
    • /
    • 2001
  • This study demonstrated the feasibility of tape casting method to fabricate soda borosilicate glass-coated stainless steel electrostatic chucks(ESC) for low temperature semiconductor processes. The glass coatings on the stainless steel substrates ranged from 100 $\mu\textrm{m}$ to 150 $\mu\textrm{m}$ thick. The adhesion of the glass coatings was found to be excellent such that it was able to withstand moderate impact tests and temperature cycling to over 300$^{\circ}C$ without cracking and delamination. The electrostatic clamping pressure generally followed the theoretical voltage-squared curve except at elevated temperatures and higher applied voltages when deviations were observed to occur. The deviation is due to increased leakage current at higher temperature and applied voltage as the electrical resistivity drops.

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Blockade of Intrinsic Oscillatory Activity of Cerebellar Purkinje Cells by Apamin and Nickel

  • Seo, Wha-Sook;Strahlendorf, Jean-C.;Strahlendorf, Howard-K.
    • The Korean Journal of Physiology and Pharmacology
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    • 제1권5호
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    • pp.477-484
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    • 1997
  • Intracellular recordings of oscillatory firing (bursting activity) were obtained from Purkinje cells (PCs) in rat cerebellar slices. Apamin inhibited post-burst hyperpolarizations (PBHs) progressively and finally terminated oscillatory firing activity of PCs. Apamin did not affect the amplitude or duration of the after-hyperpolarization (AHP) between spikes within the burst. In the voltage clamp mode, apamin shifted the whole-cell, quasi-steady state I/V relationship in an inward direction and abolished the zero slope resistance (ZSR) region by blocking outward current. Nickel ($Ni^{2+}$) terminated oscillatory activity and also abolished the ZSR region. However, $Ni^{2+}$ did not have progressive blocking action on the post-burst hyperpolarization before it blocked oscillatory activity. $Ni^{2+}$ blocked an inward current at potentials positive to approximately -65 mV, which was responsible for the ZSR region and outward current at more negative potentials. These data indicated that oscillatory activity of PCs is sustained by a balance between a slow $Ni^{2+}$-sensitive inward current and an apamin-sensitive outward current in the region of ZSR of the whole-cell I/V curve.

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