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建立了双栅MOS器件反型层积分电荷Qi的集约模型.该模型考虑了反型层载流子的量子限制效应,使其适用于纳米尺度的器件应用.基于以前关于Ge的研究,通过建立关于Qi的表面势表达式,可得到一个隐含Qi的方程,从而求得Qi的值.将该模型计算结果与目前已发表的模型计算结果以及自洽求解一维泊松方程和薛定锷方程的数值模拟程序Schred的模拟结果进行了比较.结果表明,该模型在较大的硅层厚度变化范围内均与数值模拟程序的计算结果吻合得很好,显示出其相对与目前发表的其他模型的优越性. 相似文献
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二维短沟道MOSFET阈值电压分析模型 总被引:1,自引:0,他引:1
随着器件尺寸的进一步减小,由量子效应导致的能带分裂对MOSFET中阈值电压特性的影响变得越来越重要.提出了一个包含量子效应(QME)的短沟道金属氧化物场效应晶体管(MOSFET)分析的阈值电压模型,该模型建立在求解包含量子校正的泊松方程的基础上.分析在泊松方程中考虑量子效应后建立的分析的阈值电压模型可知:随着器件尺寸的减小,由量子效应和短沟道效应引起的阈值电压的升高变得越来越严重.本模型的优点是没有引入额外的物理参数. 相似文献
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在"电气工程基础"课程的过电压教学过程中,空载架空线路的长线电容效应是一个十分重要的概念。本文从均匀架空长线的分布参数等效模型及其端点的等效集中参数模型出发,对电容效应不同的补偿方式进行等效参数分析和讨论,同时对复杂的补偿方法进行了等效分析.本文的讨论对电气工程课程的教学和工程实践具有一定的参考价值。 相似文献
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遗传算法在双向反射分布函数模型参数优化中的应用 总被引:8,自引:1,他引:7
对以大理石为代表的材料进行了双向反射分布函数测量实验,得出了样品的半球反射率,并研究了其随入射、反射天顶角等参数变化的规律。采用遗传算法建立了金刚砂和大理石材料的双向反射分布函数的参数模型,对模型进行参数反演时,通过遗传算法进行优化。拟合后的实验数据曲线表明,利用遗传算法得到的结果具有较好的一致性。 相似文献
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一种基于Weibull函数的单粒子注入脉冲模型 总被引:1,自引:1,他引:0
单粒子效应是当前集成电路抗辐射加固的研究重点之一.根据空间辐射粒子特点,提出一种基于Weibull函数的单粒子注入脉冲模型,该模型利用Weibull函数对瞬时脉冲直接进行电路级描述.实验证明,该模型与传统器件级电流注入脉冲模型的SER统计数据拟合度高达98.41%,同时可将电路模拟时间缩短3个数量级,在高速超大规模集成电路的单粒子效应研究中,具有明显的模拟速度优势,为深亚微米级的抗辐射加固研究提供了坚实的理论基础. 相似文献
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研究了超薄栅氧MOS器件的直接隧穿(direct tunneling,DT)电流模型问题.利用修正的WKB近似方法(modified WKB,MWKB)得到电子隧穿栅氧的几率,利用修正的艾利函数(modified Airy function,MAF)方法计算得到在高电场条件下载流子的量子化能级,从而计算出在不同偏置条件下的DT电流.模型实现了nMOSFET's栅隧穿电流的二维模拟,可以模拟在不同栅漏偏置条件下的器件工作情况,具有较广泛的适用性.通过对比表明,本模型能够与实验结果很好地吻合,且速度明显优于数值方法.利用模型可很好地对深亚微米MOS器件的栅电流特性进行预测. 相似文献
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研究了超薄栅氧MOS器件的直接隧穿(direct tunneling,DT)电流模型问题.利用修正的WKB近似方法(modified WKB,MWKB)得到电子隧穿栅氧的几率,利用修正的艾利函数(modified Airy function,MAF)方法计算得到在高电场条件下载流子的量子化能级,从而计算出在不同偏置条件下的DT电流.模型实现了nMOSFET's栅隧穿电流的二维模拟,可以模拟在不同栅漏偏置条件下的器件工作情况,具有较广泛的适用性.通过对比表明,本模型能够与实验结果很好地吻合,且速度明显优于数值方法.利用模型可很好地对深亚微米MOS器件的栅电流特性进行预测. 相似文献
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J. Li P. C. Ma W. S. Chow C. K. To B. Z. Tang J.‐K. Kim 《Advanced functional materials》2007,17(16):3207-3215
Critical factors that determine the percolation threshold of carbon nanotube (CNT)‐reinforced polymer nanocomposites are studied. An improved analytical model is developed based on an interparticle distance concept. Two dispersion parameters are introduced in the model to correctly reflect the different dispersion states of CNTs in the matrix—entangled bundles and well‐dispersed individual CNTs. CNT–epoxy nanocomposites with different dispersion states are fabricated from the same constituent materials by employing different processing conditions. The corresponding percolation thresholds of the nanocomposites vary over a wide range, from 0.1 to greater than 1.0 wt %, and these variations are explained in terms of dispersion parameters and aspect ratios of CNTs. Important factors that control the percolation threshold of nanocomposites are identified based on the comparison between modeling data and experimental results. 相似文献
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本文在分析了SPICE II-MOS2,MOS3模型中所存在的问题之后,重新建立了一个实用于电路模拟的微米级MOSFET解析模型──MOS5模型(本文仅限于介绍其开启电压模型部分).经实验证明,此模型适用于对不同工艺制得的各种尺寸增强型MOS管的开启电压模拟(L_(eff)≥1.0μm).与原SPICEII-MOS2,MOS3模型相比,此新模型具有参数简单易得、物理意义明确、以工艺参数为主等特点.此模型现已装入SPICE II程序中,达到了实用的目的,并可对VLSI设计与制造起一定的指导作用. 相似文献
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Ali F. Almutairi Awatef K. Ali Mehmet Hakan Karaata 《Wireless Communications and Mobile Computing》2005,5(2):209-217
In this paper, we propose a new Generalized Distribution‐Based Handover (DBHO) to deal with the inefficient utilization of spectral resources due to the non‐uniform cell loads. The DBHO scheme is different from the existing adaptive schemes since it uses a new criterion to initiate handover when moving from/to a congested cell. Two risk factors are used to dynamically change handover boundaries according to the distribution of traffic loads. This controls the handover initiation process such that a user in a congested cell that is moving to a free cell is allowed to initiate a handover to a new cell earlier, as long as the signal received from the target cell is higher than a certain threshold. While delaying the handover initiation process for a user moving in the opposite direction, as long as the signal received from the serving cell is not lower than a certain threshold. Our results show a substantial reduction in the handover and call dropouts rates. Our scheme is complementary to the existing adaptive schemes proposed in the literature. The proposed scheme also gives cellular system designers a new tool to optimize the overall network performance by initiating handovers based on the traffic intensities. Frequent handovers increase the load on switching networks, which consequently degrades the Quality of Service (QoS). Existing handover schemes usually use parameters such as the received signal strength for initiating a handover with some additional measurements to reduce unnecessary handovers and call dropouts. These schemes perform well when cell loads are somewhat evenly distributed, but fail to account for nonuniform traffic, as is often the case in microcells. Hence, it is desirable to design efficient handover schemes to avoid unnecessary handovers, reduce call dropouts and yet dynamically adapt to the variation of traffic among cells. In this paper, we present a new adaptive handover scheme that dynamically changes the handover boundaries to balance cell loads and to effectively reduce the average number of handovers. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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本文基于两点基本假设,提出了一个简化的非晶硅薄膜场效应晶体管模型,在整个电压范围内,得到了电流的解析表达式.与现有的实验结果进行拟合,理论值与实验值符合良好.本文还分析了非晶硅薄膜晶体管输出特性中源漏串联电阻效应,结果表明,源漏串联电阻受栅压调制,近似与栅压的平方成反比.本文还解释了开启电压随温度线性变化规律.模型可用于优化非晶硅薄膜晶体管的设计. 相似文献
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基于小波变化阈值的光干涉信号去噪 总被引:2,自引:2,他引:0
为了提高参数估计的精确度,根据光反馈自混合干涉信号的特点,对光反馈自混合干涉信号进行了去噪研究。在多分辨分析小波阈值去噪的基础上,采用了一种改进的阈值函数,克服了硬阈值函数不连续的缺点,解决了软阈值函数中存在的恒定偏差,并且具有软硬阈值函数不可比拟的灵活性。构建了光反馈自混合干涉理论模型,通过对其仿真波形和实测波形的处理,比较了三种阈值函数的去噪效果。结果表明,无论是在去噪效果上,还是在信噪比增益和最小均方误差意义上均优于传统的软硬阈值方法。 相似文献
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《Organic Electronics》2014,15(9):1965-1971
By applying a single or double stimulating pulse to a conjugated polymer, we theoretically realize the population inversion between the generated intragap states. The simulations are performed within the framework of an extended version of the one-dimensional Su–Schrieffer–Heeger tight-binding model combined with a nonadiabatic evolution method. In discussions, we mainly compare the stimulating intensity thresholds between the two different pumped modes, at which the population inversion in polymer is reached. It is found that, the stimulating intensity threshold can be remarkably reduced by employing a double pulse rather than a single one. Effect of the lasting time for each pulse on the threshold is also discussed. We then propose a new optical-pumped mode to realize the population inversion in polymers, which is potentially of great importance for polymer lasers. 相似文献
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在分析双模噪声模型统计特性的基础上提出自适应小波阈值算法。新算法中设计改进的阈值函数和控制函数,克服了传统硬、软阈值法的不足,并且自适应得到最佳控制因子。该算法对加入双模噪声的信号进行闭环反馈处理:小波分解、阈值量化处理、小波逆变换重构信号、控制函数寻优。Matlab 2012 a仿真结果表明,该算法相对于传统硬、软阈值法,去噪图形曲线清晰、光滑、连续性好,信噪比分别提高9 dB和4 dB。在双模噪声背景下,自适应小波阈值去噪有效、可行,拓展了小波阈值算法的应用。 相似文献