Doping and processing epitaxial GexSi1−x films on Si(100) by ion implantation for Si-based heterojunction devices applications

The question of whether one can effectively dope or process epitaxial Si(100)/GeSi heterostructures by ion implantation for the fabrication of Si-based heterojunction devices is experimentally investigated. Results that cover several differention species (B, C, Si, P, Ge, As, BF₂, and Sb), doses (10¹³ to 10¹⁶/cm²), implantation temperatures (room temperature to 150°C), as well as annealing techniques (steady-state and rapid thermal annealing) are included in this minireview, and the data are compared with those available in the literature whenever possible. Implantation-induced damage and strain and their annealing behavior for both strained and relaxed GeSi are measured and contrasted with those in Si and Ge. The damage and strain generated in pseudomorphic GeSi by room-temperature implantation are considerably higher than the values interpolated from those of Si and Ge. Implantation at slightly elevated substrate temperatures (e.g., 100°C) can very effectively suppress the implantation-induced damage and strain in GeSi. The fractions of electrically active dopants in both Si and GeSi are measured and compared for several doses and under various annealing conditions. Solid-phase epitaxial regrowth of GeSi amorphized by implantation has also been studied and compared with regrowth in Si and Ge. For the case of metastable epi-GeSi amorphized by implantation, the pseudomorphic strain in the regrown GeSi is always lost and the layer contains a high density of defects, which is very different from the clean regrowth of Si(100). Solid-phase epitaxy, however, facilitates the activation of dopants in both GeSi and Si, irrespective of the annealing techniques used. For metastable GeSi films that are not amorphized by implantation, rapid thermal annealing is shown to outperform steady-state annealing for the preservation of pseudomorphic strain and the activation of dopants. In general, defects generated by ion implantation can enhance the strain relaxation process of strained GeSi during post-implantation annealing. The processing window that is optimized for ion-implanted Si, therefore, has to be modified considerably for ion-implanted GeSi. However, with these modifications, the mature ion implantation technology can be used to effectively dope and process Si/GeSi heterostructures for device applications. Possible impacts of implantation-induced damage on the reliability of Si/GeSi heterojunction devices are briefly discussed.     

基于SDL协议的QoS实现方案

简单数据链路协议（SDL）作为一种新型的IP over技术，其简单性和低开销更能适应高速传输链路的要求，并提供下一代光分组交换网所需要的操作维护管理功能，如何提供服务质量保证（QoS）是IP传输中的核心技术之一，文章介绍了IETF提出的两种实现QoS的业务模型；集成业务模型和差分业务模型，以及SDL；提出了一种基于SDL链路协议上的Diffserv over MPLS的QoS实现方案。     

矿灯式甲烷测报仪设计

给出了一种能够在0~4%浓度范围内对环境中的甲烷浓度进行检测报警的低成本便携式甲烷测报装置的设计。装置采用三维数表的方法逐点修正、补偿甲烷传感器零点、灵敏度系数随温度的变化。采用LCD显示检测值,灯光声响闪烁方式报警。测试结果表明,甲烷气体浓度测量误差小于±0.1%。装置与矿灯结合,可构成便携式甲烷测报型矿灯,应用于井下照明和甲烷测报。     

强光照条件下智能车辆导航路径图像分割方法

OTSU法（最大类间方差法）被认为是图像分割中阈值自动选取的最优方法之一,针对自主开发的视觉导航区域交通智能车辆（Cyber Car）的导航路径在强光照条件下不能直接应用此方法取得准确分割效果的问题,提出了一种基于区域的罗伯特梯度算子的图像分割方法。分割实验表明,与OTSU法分割效果相比,采用的图像分割方法能够准确地对强光照条件下的导航路径图像进行分割,并具有更好的实时性。     

一种新型的GEP算法及应用研究

提出一种适合于GEP表达式树构造的新方法,以及相应的新解码方法(GPED).通过实验对比,GPED可大大缩短演化时间.提出一种新的算法GPEP,将GPEP应用于碎石桩复合地基承载力预测,结果表明GPEP算法在预测精度和演化效率上均超过遗传神经网络、GP等算法.     

Nondestructive Freshness Discriminating of Shrimp Using Visible/Near-Infrared Hyperspectral Imaging Technique and Deep Learning Algorithm

In this study, visible and near-infrared hyperspectral imaging (HSI) technique combined with deep learning algorithm was investigated for discriminating the freshness of shrimp during cold storage. Shrimps were labeled into two freshness grades (fresh and stale) according to their total volatile basic nitrogen contents. Spectral features were extracted from the HSI data by stacked auto-encoders (SAEs)-based deep learning algorithm and then used to classify the freshness grade of shrimp by a logistic regression (LR)-based deep learning algorithm. The results demonstrated that the SAEs–LR achieved satisfactory total classification accuracy of 96.55 and 93.97% for freshness grade of shrimp in calibration (116 samples) and prediction (116 samples) sets, respectively. An image processing algorithm was also developed for visualizing the classification map of freshness grade. Results confirmed the possibility of rapid and nondestructive detecting freshness grade of shrimp by the combination of hyperspectral imaging technique and deep learning algorithm. The SAEs–LR method adds a new tool for the multivariate analysis of hyperspectral image for shrimp quality inspections.     

混合系统建模理论与混合系统模型

在现代工程仿真中,大部分仿真对象表现出同时具有连续和离散对象的特征,利用现有的离散或者连续建模理论不能全面的反应出对象特性,需要对混合系统的建模进行相应的理论研究.从系统理论出发,围绕着系统的连续属性和离散属性,以及他们对系统信息的响应,还有他们之间的相互作用为中心,建立混合系统模型的形式化表达和系统理论基础,并在此基础上建立了混合系统模型.以此模型为基础,在实践中为某大型仿真项目中的工程对象建立了混合模型,在仿真中得到有效的应用.     

热声制冷技术的研究状况

对国内外热声制冷技术的研究状况进行了综述 ,总结了热声制冷的各种特点与待解决的问题 ,并提出了目前该领域研究的几个热点方向。     

双热流法测定低温真空下固体界面的接触热阻

本文介绍了低温真空下固体界面间的接触热阻机理,重点介绍一种采用双热流计法既能精确测量圆柱型又能测量薄片型试样间接触热阻的装置,该装置还能同时测量材料的热导率。同时,文中给出一些材料在低温真空下的接触热阻值。     

生物表面活性剂在溢油污染处理中的应用现状综述

近年来,溢油事件频频发生,溢油污染物的介入给水环境健康构成了极大的威胁.如何去除溢油污染物已成为国内外研究者关注的热点之一.目前,物理化学方法仍是处理溢油的首选手段,但其并不能从根本上去除水体中的石油污染物,甚至有可能造成二次污染.生物方法具有低毒、环境友好等特点,具有极高的应用前景,其中生物表面活性剂是生物法处理溢油的核心.本文将对生物表面活性剂及其在溢油处理中的应用进行详细阐述,以期为溢油的应急处理或最终处置提供参考.