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Over the years, the approach of cylindrical gate MOSFETs has attracted several research initiatives due to the very inherent benefit of the cylindrical geometry over other conventional planar structures. Nowadays, the present boon in the research field of nanoscale device physics is attributed to a large extent by the development of junctionless devices. In our current research endeavor, we have for the first time proposed a new idea by incorporating the innovative concept of work function engineering by the continuous horizontal variation of mole fraction in a binary metal alloy gate into a junctionless cylindrical gate MOS structure, thereby presenting a new device structure, a junctionless work function engineered gate cylindrical gate MOSFET (JL WFEG CG MOSFET). We have presented a rigorous analytical modeling of the proposed JL WFEG CG MOS structure by solving the two dimensional Poisson’s equation in cylindrical co-ordinates. Based on this analytical modeling, an overall performance comparison of the proposed JL WFEG CG MOS and normal JL CG MOS structure has been investigated in order to testify the improved performance of the proposed JL WFEG CG structure over its normal JL CG equivalent in terms of reduced short channel effects, threshold voltage roll off, drain induced barrier lowering and superior current driving capability. The results obtained from our analytical analysis are found to be in good agreement with the simulation results, thereby establishing the accuracy of our modeling. 相似文献
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Poly-Si thin film transistors (TFTs) exhibit large OFF-state reverse leakage currents since their channel conduction is controlled by the gate-induced grain barrier lowering (GIGBL). This also leads to the presence of the pseudosubthreshold region in the transfer characteristic. In this paper, we report a novel poly-Si multiple-gate TFT (MG-TFT), where the front gate consists of three sections with two different materials, in order to reduce the OFF-state leakage current with no significant change in the ON-state current. We demonstrate that the dominant conduction mechanism in the channel can be controlled entirely by the accumulation charge density modulation by the gate (ACMG) instead of the GIGBL, leading to a steep subthreshold slope without any pseudosubthreshold region when compared to an asymmetrical double-gate poly-Si TFT (DG-TFT), resulting in a significantly reduced OFF-state leakage current. Using two-dimensional (2-D) and two-carrier device simulation, we have analyzed the various performance and design considerations of the MG-TFT and explained the reasons for the improved performance of the MG-TFT. 相似文献
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探究窄深型弯曲河段三维水流结构,使用声学多普勒流速仪(ADV)对正弦派生弯道水槽中40个断面12160个测点三维水流数据进行加密测量研究,研究结果表明:弯曲岸壁形态改变了水流结构特征,曲率为0断面附近区域为水流动力轴线在左右两岸摆动的过渡区;在左右两岸侧,纵向流速沿程波动分布,波动周期相同相位相差180°,且在凹岸处存在小流速区;各断面存在中心区近底主环流和近岸近水面反向小环流,部分断面近岸近底还出现与中心环流同向的小环流,环流强度最小值出现在各弯段弯顶附近。实验数据可为连续多个弯道数值模拟提供数据验证参考。 相似文献
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We studied the surface potential properties of nanoscale domain-engineered structures on near-stoichiometric LiNbO3 crystals using Kelvin probe-based, electrostatic force microscopy. The surface potential image reflected in the domain structures
could not be obtained clearly, because the spontaneous polarizations of the domains were neutralized by the in-air room temperature
(298 K) screening charges. However, using heat-treatment in a vacuum, the surface potential image became clear, because of
the decrease of the spontaneous polarizations and the protection of the screening charge adsorption. Furthermore, the surface
potential contrast and polarity of the nanoscale domain-engineered structures could be changed repeatedly by changing the
temperature between 298 and 393 K in the vacuum. 相似文献
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内燃机余热回收技术对节能减排具有重要意义,其中超临界二氧化碳(S-CO2)动力循环系统因成本低、环境友好等优点,受到越来越多的关注。烟气换热器作为S-CO2动力循环系统的关键部件,其换热性能直接影响循环整体效率。印刷电路板换热器具有换热效率高、结构紧凑的特点,但目前鲜有在内燃机余热回收上的应用。因此,本文开展印刷电路板烟气换热器的结构设计及优化工作。设计了3种S-CO2侧流道结构的烟气换热器,并通过数值模拟,对比了不同流道结构对换热器内部流动及换热性能的影响。结果表明,镂空流道烟气换热器的单位质量换热量与Kv值远高于直角流道换热器和圆角流道换热器,说明镂空流道印刷电路板换热器可以更好地满足小型化、紧凑化的要求。 相似文献
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基于UPFC的风电场稳定性动态仿真研究 总被引:1,自引:0,他引:1
异步风力机因风速变化的不规律会导致电网电压崩溃.UPFC是FACTS元件中装置中功能最强大的元件,可以维持风电场电压和系统稳定.运用UPFC、风力机和异步发电机的数学模型,在Matlab/Simulink中建立了带UPFC的风电场仿真模型,通过研究风速骤变时带与不带UPFC的风电场功率、电压状况,验证了UPFC对风电场电压的支持作用,并能维持风电场及系统的稳定,保证风力发电机的持续运行. 相似文献
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缓变弯道河道冲刷试验研究 总被引:2,自引:0,他引:2
有关弯道水流及其河道演变特性的研究一直为人们所关注。本文引入了在直线段和单一曲率圆弯道间插入曲率渐变的过渡段这一新的弯道型式,舒缓水流冲击力和离心力作用,以减轻水流对河床及堤身、堤脚的冲蚀破坏。作者首先对这一弯道和圆弯道的水流流速、副流强度进行了数值模拟的计算和比较;又通过变换床沙、流量及放水时间,进行了24组合的动床试验;最后,通过整理分析所有实验数据,对插有缓变曲线的弯道的减蚀作用进行了探讨。结果表明:插有缓变曲线的弯道可以减轻水流对两岸堤身和堤脚的冲蚀破坏;在弯道同一横断上的最大冲深与沙洲波高的比值最终稳定在0.58。 相似文献
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含淹没刚性植被明渠水流特性的试验研究 总被引:1,自引:0,他引:1
水生刚性淹没植被大量存在于海洋、河流、水库、湖泊及运河中,对水流结构、河床冲淤、洪水演进及航运造成较大影响。为了准确掌握水生刚性淹没植被对水流的影响,需要对含植被水流问题进行系统的研究。本文利用三维激光多普勒测速仪等仪器对实验室水槽中四种排列(全覆盖平行排列、全覆盖交错排列、半覆盖平行排列、半覆盖交错排列)、四种淹没度下水生刚性淹没植被(用玻璃棒代替)的扰流特性进行了测量,并对实测结果进行了系列分析。试验结果表明,植被的密度、排列方式和淹没度对水面坡降、水头损失、水流流速和紊流强度都有明显的影响。 相似文献
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《电工电能新技术》2015,(8)
转子结构影响电机的气隙磁通密度,从而影响无轴承永磁薄片电机可控性、转矩脉动以及径向悬浮力等性能。本文从无轴承永磁薄片电机不同的永磁转子结构(表贴式、表面嵌入式、Halbach阵列以及平行充磁环形转子)出发,对其机械强度、磁场分布等进行对比分析。基于麦克斯韦张量法提出了无轴承永磁薄片电机在任意极对数下的数学模型,运用Ansoft对其计算精度进行验证分析,并对具有不同永磁转子结构的无轴承永磁薄片电机径向悬浮力与悬浮力绕组电流之间的关系进行对比分析,得到不同永磁转子结构的优缺点。样机试验验证了仿真结果的正确性,研究结果对无轴承永磁薄片电机转子的参数优化设计具有参考价值。 相似文献
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为了使静止无功补偿器(SVC)更有效地发挥其调控系统电压的作用,提出了一种对SVC采用变调差率控制的新方法。基于RSCAD/RTDS实时数字仿真平台建立仿真模型,分别研究了在零调差率、恒调差率以及变调差率三种U-I特性下SVC对系统母线电压的控制效果。结果显示,采用变调差率特性的SVC综合了前两者控制策略的优点,既实现了如零调差率特性减小电压偏差的效果,又达到了与恒调差率特性完全相同的控制范围。 相似文献
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为了使静止无功补偿器(SVC)更有效地发挥其调控系统电压的作用,提出了一种对SVC采用变调差率控制的新方法.基于RSCAD/RTDS实时数字仿真平台建立仿真模型,分别研究了在零调差率、恒调差率以及变调差率三种U-I特性下SVC对系统母线电压的控制效果.结果显示,采用变调差率特性的SVC综合了前两者控制策略的优点,既实现了如零调差率特性减小电压偏差的效果,又达到了与恒调差率特性完全相同的控制范围. 相似文献
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为了得到三相感应电动机Semihex^TM接法单相运行时的瞬态特性,根据三相感应电动机在A、B、C相坐标系下的动态数学模型及三相感应电动机采用Semihex^TM接法时的边界方程,编制计算机仿真程序,对三相感应电动机单相Semihex^TM运行的瞬态过程进行仿真研究,对仿真结果进行分析:用对称分量法分析三相感应电动机Semihex^TM接法时的不对称系统,确定电容的数值。试验证明了分析方法的正确性。 相似文献
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为研究天然气自热重整质子交换膜燃料电池各级化学反应热的高效利用模式,提出一种耦合利用重整制氢各级反应热与燃料电池余热的发电系统,利用天然气自热重整技术制取富氢合成气,以“温度对口、梯级利用”原则,利用重整子系统各级化学反应热与燃料电池子系统余热逐级加热自热重整用工质水产生高温蒸汽,形成回热系统。通过建立能量、质量、电化学反应方程多物理场耦合的系统模型,分析系统氢气产量与发电效率,并研究进料温度、蒸汽燃料比、空气燃料比对系统性能的影响。结果表明,该系统发电效率为47.41%,较无耦合回热系统提高5.4百分点,适宜的进料温度450~500 ℃,蒸汽燃料比1.75~2.00,空气燃料比2.35~2.65。 相似文献