Effects of vacancy structural defects on the thermal conductivity of silicon thin films

Vacancy structural defect effects on the lattice thermal conductivity of silicon thin films have been investigated with non-equilibrium molecular dynamics simulation.The lattice thermal conductivities decrease with increasing vacancy concentration at all temperatures from 300 to 700 K.Vacancy defects decrease the sample thermal conductivity,and the temperature dependence of thermal conductivity becomes less significant as the temperature increases.The molecular dynamics result is in good agreement with the theoretical analysis values obtained based on the Boltzmann equation.In addition,theoretical analysis indicates that the reduction in the lattice thermal conductivity with vacancy defects can be explained by the enhanced point-defect scattering due to lattice strain.     

新型Sb基二类超晶格红外探测器

InAs/Ga(In)SbⅡ类超晶格材料由于特殊的二型能带结构,可以通过人造低维结构获得类似于体材料的带间吸收,从而获得较高的量子效率;另外,通过调节材料参数调节能带结构,器件响应波段可调;通过能带结构设计抑制俄歇复合,获得较小的暗电流和较高的器件性能。因为以上特有的材料性能和器件特性,Sb基二类超晶格在国际上被认为是第三代红外焦平面探测器的优选材料。对二类超晶格材料的设计和器件特性进行了研究,设计了峰值波长4μm的nBn结构的中波红外探测器,在没有蒸镀抗反膜的条件下,77 K温度下测试得到的峰值探测率为2.4×1011cm Hz1/2W-1,计算得到的量子效率为47.8%,峰值探测率已经接近目前的碲镉汞中波红外探测器器件性能。研究结果充分显示了二类超晶格优越的材料和器件性能。     

A Theoretical Investigation of Slot Waveguide Bragg Gratings

Bragg grating, structures based on dielectric slot waveguide, are investigated theoretically for potential applications as optical resonators and filters. Important device performance parameters, such as the reflection spectrum, the peak reflectivity, and the field confinement factor, are examined as functions of key waveguide and grating design parameters.     

Receiver IQ Imbalance Estimation via Pure Noise for 60 GHz Systems

This paper proposes to estimate receiver (RX) IQ imbalance via pure noise for 60 GHz millimeter-wave systems. We study the impact of RX IQ imbalance on noise, and derive the maximum-likelihood algorithm to acquire the imbalance parameters, which is decoupled from transmitter IQ imbalance, channel response, and carrier offset. Also, the proposed method has low computational complexity and meets the low-power and low-cost requirements of 60 GHz systems. Moreover, the jitter performance of the estimation reaches the corresponding Cramer–Rao lower bound under a wide range of imbalance parameters.     

中兴通讯IP over WDM解决方案

介绍了IP网络的发展趋势,承载电信级业务的IP承载网的3种组网方式,着重介绍了IP over WDM解决方案的优势和特点。     

一种无人机扩频遥控系统的性能分析

在剖析无人机扩频遥控系统组成的基础上,对无人机扩频遥控系统的处理增益、抗干扰容限及保密性能做了具体的分析,对无人机扩频遥控系统的雷达截获概率做了深入的探讨。     

Phase characterisation of metalenses

Metalenses have emerged as a new optical element or system in recent years, showing superior performance and abundant applications. However, the phase distribut...     

基于改进HOG特征值的车标检测与识别方法

车标自动识别是智能交通系统中机动车辆信息采集的关键内容。根据车标具有丰富边缘信息的特征,文章应用HOG(梯度方向直方图)的特征值,采用SVM(支持向量机)的分类工具实现了车标的快速检测与识别。并提出一种改进的HOG特征值,在车标检测识别准确率上取得了显著的效果。大量实验数据以及在智能交通系统中的应用表明,该方法具有较强的鲁棒性和实用价值。     

A Network-Level Connected Autonomous Driving Evaluation Platform Implementing C-V2X Technology

With the emerging connected autonomous driving paradigm,more advanced applications leveraging vehicular communications are drawing tremendous attentions.In orde...