制备过程中对VO_2薄膜热致相变光电性能的控制

本文利用真空还原V2 O5的方法制备出优质对VO2 薄膜 ;研究了不同真空还原时间VO2 薄膜热致相变过程中光电性能的影响 ;利用XPS、XRD对薄膜的化学状态和结晶状态进行了研究。制备的薄膜高 /低温电阻变化最大达到三个数量级 ,90 0nm处的光学透过率在相变前后改变了 40 %左右 ,热致相变性能优良。讨论了不同的真空还原时间下VO2 薄膜热滞回线的宽度、相变温度点以及高低温光透射性能。最后给出了最佳真空还原时间。     

提高激光三角法测量精度的新方法

激光三角法是一种几何测量的重要方法,目前已广泛用于测量位移和三维面形,但这测量系统的测量精度不高,一个主要的问题就是光源光强不稳定;本文提出用光学双稳装置来稳定激光光泊的光强,并用于测量金属板材,实验结果：将光学双稳装置用于激光三角法使系统的测量精度大大提高。     

多目标宏形状特征点集快速检测技术研究

提出一种新的图像多目标特征点集检测技术。该技术研究了多目标分割、目标细微形状提取和宏形状提取,进而检测表示目标宏形状特征的特征点集。各目标宏形状特征点集进行识别与跟踪．研究了上述技术的快速实现。实际DSP跟踪系统处理结果表明该技术计算量小,抗噪能力强且准确性高,能准确识别目标,适用于实际图像目标特征点集的检测。     

Ultraviolet detectors based on epitaxial ZnO films grown by MOCVD

High-quality zinc oxide (ZnO) films were epitaxially grown on R-plane sapphire substrates by metalorganic chemical vapor deposition at temperatures in the range of 350°C to 600°C. In-situ nitrogen compensation doping was performed using NH₃. Microstructural and optical properties of the films, as well as the N-doping effects, were studied. The metal-semiconductor-metal ultraviolet sensitive photodetectors were fabricated on N-doped epitaxial ZnO films. The detector showed fast photoresponse, with a rise time of 1 μs and a fall time of 1.5 μs. Low-frequency photoresponsivity, on the order of 400 A/W at 5 V bias, was obtained.     

Technology trends toward a system-in-a-module in power electronics

Currently, assemblies of power semiconductor switches and their associated drive circuitry are available in modules. From a few 100 watts downward, one finds silicon monolithic technology as the integration vehicle, while upward into the multi-kilowatt range, mixed mode module construction is used. This incorporates monolithic, hybrid, surface mount and wirebond technology. However, a close examination of the applications in motor drives and power supplies indicates that there has been no dramatic volume reduction of the subsystem. The power semiconductor modules have shrunk the power switching part of the converter, but the bulk of the subsystem volume still comprises the associated control, sensing, electromagnetic power passives and interconnect structures. The paper addresses the improvement of power processing technology through advanced integration of power electronics. The goal of a subsystem in a module necessitates this advanced integration. The central philosophy of this technology development research is to advance the state of the art by providing the concept of integrated power electronics modules (IPEMs). The technology underpinning such an IPEM approach is discussed. The fundamental functions in electronic power processing, the materials, processes and integration approaches and future concepts are explained.     

下一代移动通信系统中的信道分配策略

下一代移动通信系统是一个由微蜂窝、宏蜂窝和卫星小区构成的多层覆盖体系结构,在该体系结构中,多媒体业务将占有很大的比重。基于这一特点,建立新的通信系统模型, 并通过将软-通信质量概念与统计复用技术相结合,获得了一种较好的信道分配方法。通过对算法进行系统仿真,比较了它与传统信道分配算法的优劣。仿真结果表明:新的信道分配方法会增加系统容量,减少通信业务阻塞概率,极大的提高整个系统的性能。     

均匀会聚菲涅尔透镜设计及性能研究

提出了一种均匀会聚菲涅尔透镜设计方案,透镜基于离轴聚焦设计,采用方形非旋转对称结构,利用光强叠加实现均匀会聚.文章基于该方法建立了几何聚光比分别为56、100、400和900倍,焦距分别为300 mm、400 mm、500和600 mm的透镜模型,并利用光学仿真软件对其聚光性能进行分析.研究结果表明:基于该方法设计的透镜能够较好地实现均匀会聚,且聚光效率和聚光分布均匀度均超过80％,可以满足聚光光伏需要.     

基于动态逆与QFT 的鲁棒飞行控制器

针对保证无人战斗机控制器的解耦性能和鲁棒性能问题,设计一个某无人战斗机的姿态控制器。将动态逆(DI)和定量反馈理论(QFT)相结合,用动态逆实现无人战斗机控制的动态解耦,用定量反馈理论保证控制器的鲁棒性能,并以实例进行仿真结果分析。仿真结果表明:在气动数据变化±30%的范围内,DI与QFT控制器可以实现对飞机姿态的精确控制,能很好地解决飞机的姿态控制问题,有较好的工程应用价值。     

HYBRID INTERNET TRAFFIC CLASSIFICATION TECHNIQUE1

Accurate and real-time classification of network traffic is significant to network operation and management such as QoS differentiation, traffic shaping and security surveillance. However, with many newly emerged P2P applications using dynamic port numbers, masquerading techniques, and payload encryption to avoid detection, traditional classification approaches turn to be ineffective. In this paper, we present a layered hybrid system to classify current Internet traffic, motivated by variety of network activities and their requirements of traffic classification. The proposed method could achieve fast and accurate traffic classification with low overheads and robustness to accommodate both known and unknown/encrypted applications. Furthermore, it is feasible to be used in the context of real-time traffic classification. Our experimental results show the distinct advantages of the proposed classification system, compared with the one-step Machine Learning (ML) approach.     

风冷压缩单元式空调器节能探讨

从分析风冷压缩单元式空调器的制冷原理入手,提出了两种空气源热泵热水模块＋空气源压缩制冷模块机,为提高能源综合利用效率、节约建筑能耗提供了一定的实践思路。