一种求解电大平台天线互耦的时域积分方程快速算法

该文针对电大尺寸平台天线互耦问题,提出一种基于几何绕射理论加速的时域积分方程快速算法。在求解时域积分方程的经典时间步进法基础上,引入几何绕射理论中的绕射线寻迹,提高了迟滞积分的计算效率。数值算例证明了该方法能够有效地加速时间步进法的求解过程,对电大平台天线布局优化设计具有理论指导意义。     

光纤非本征法布里-玻罗传感器兰姆波检测灵敏度分析

基于兰姆波的结构工况检测技术在评估复合材料和金属结构的安全性和耐久性方面发挥着重要的作用。作为对传统的压电换能器（PZT）的一种很好的替代,光纤传感器在传感方面的应用正被广泛地挖掘出来,包括兰姆波检测。本文从理论上建立了超声兰姆波作用下光纤非本征法布里．玻罗（EFPI）传感器参数与其输出性能之间的关系。数值结果显示了传感器的性能与其相对于声源的方向角以及传感器的计量长度与超声波长的比值相关。所得出的结论对于EFPI传感器精确地探测兰姆波提供了理论依据。     

Distributed uplink scheduling and rate control in cdma2000 using adaptive antenna arrays

Distributed uplink scheduling and rate control in CDMA networks are considered in the case of adaptive antenna arrays present at the base station. The system model with omnidirectional antennas is generalized to the case where adaptive antenna arrays are deployed. Rate control in a probabilistic manner is investigated. Long-term control by the base station through token bucket constraints is incorporated in the system. Monte Carlo simulation results show considerable improvement when adaptive antenna arrays are used. Optimization of the rate transition probabilities is treated in the special case of on–off scheduling.     

Analysis ofN-slot structure corrugated horn

On the space harmonics technique general formulas are derived of the characteristic equation and the equivalent wall admittance of corrugated horns withN-slot structure(each period hasN slots whose shape and depth may be the same or different). As an example, the calculated radiation patterns for a corrugated horn having dual-depth corrugations show good agreement with the measured ones.     

利用GTD分析微波双反射面天线效率

本文根据场相关定理,应用几何绕射理论(GTD),分析计算主面为抛物面,副面为任意旋转对称面的微波双反射面天线效率.通过实际证实,运算简明,效果良好.     

Imperfections and resonant tunneling in quantum-well heterostructures

We discuss effects of structural imperfections on the I-V characteristics and local density-of-states of semiconductor double-barrier heterostructures. Using a linear-chain model for GaAs/AlGaAs structures, we simulate fluctuations in layer thicknesses, defects at the heterointerfaces, and disorder.     

地球站天线极化夹角的调整

本文闸明了地球站天线产生极化夹角的原理;导出了计算极化夹角的公式;给出了全国各地具有代表性的一些地球站极化夹角值,供有关研制人员和操作人员调整地球站天线消除极化夹角影响之参考。     

Full Bridge ZVT—PWM DC—DC Converter

Abstract: A new FB - ZVT - PWM converter is proposed. The new converter operates at a fixed frequency and implements ZVS for power devices without increasing voltage in both turn - on and turn - off transient. A 80 kHz/50 W FB - ZVT - PWM boost converter using MOSFETs is analysed theoretically.     

INVESTIGATION ON RESONANT TUNNELING IN GaAs/Al_xGa_(1-x)As DBD USING TUNNELING SPECTROSCOPY

Experimental investigation on resonant tunneling in various GaAs/Al_xGa_(1-x)Asdouble barrier single well structures has been performed by using tunneling spectroscopy atdifferent temperatures.The results show that in addition to resonant tunneling via GaAs wellstate confined by Al_xGa_(1-x)As Γ-point barrier there exists resonant tunneling via GaAs well stateconfined by Al_xGa_(1-x)As X-point barrier for both indirect(x>0.4)and direct(x<0.4)cases.     

用~(19)F(p,αγ)共振核反应测深度分布非共振产额的影响

用~(19)F(p,αγ)共振核反应测量浓度深度分布是一个应用广泛的方法,发表了大量的文章。因为出射的α粒子能量低,不容易探测,所以几乎无例外的都是测γ射线。其中不少文章认为,测得的样品激发函数与靶核浓度深度分布形状是非常相似的,二者之间只差一个比例因子。实际上,这只在薄靶情况下是对的,对于厚靶,二者并不相似。