基于径向基神经网络的旋转机械故障诊断

针对旋转机械故障征兆与故障模式映射的复杂性,以及BP网络容易陷入局部极小、收敛速度慢等缺点,提出基于径向基（RBF）神经网络的风机故障诊断方法。以风机振动信号的7段频谱能量峰值作为故障特征,采用训练好的RBF网络进行故障辨识。结果表明,RBF网络能满足风机故障诊断的准确性,并在避免局部极小和节约训练时间方面有较好的实用性。     

脑启发视频用户体验评测关键技术

基于脑电图(EEG)响应趋同性的生理学机理,研究了基于脑电图响应特征的体验质量(QoE)度量方法,实现小样本稳定度量;建立网络关键性能指标(KPI)、服务关键质量指标(KQI)与QoE之间的映射关系模型。该模型可有效地提升多媒体服务和网络资源协同的优化空间,为显著提升多媒体业务支持能力提供新途径。     

基于卷积神经网络的高分遥感影像单木树种分类

树种调查一直面临着成本高、效率低、精度不高等问题.利用遥感手段能大大提高树种类型调查的工作效率、节省成本;卷积神经网络(CNN)虽然已经在自然图像分类领域取得了许多突破,但是较少有人将CNN模型用于单木树种分类.基于上述考虑,搭建出CNN模型,并与高分遥感影像相结合,进行单木树种分类.在利用高分影像半自动化构建单木树种...     

电子束纳米光刻技术研究

纳米光刻技术在微电子制作中起着关键作用 ,而电子束光刻在纳米光刻技术制作中是最好的方法之一。我们使用VB5电子束曝光系统 ,经过工艺研究 ,现已研究出最细分辨率剥离金属条为 17nm ,最小剥离电极间距为 10nm ,最细T型栅为 10 0nm。     

多摄像机在无重叠区域的目标匹配算法

基于颜色特征的目标匹配方法具有很好的区分性和直观性,但是特征本身受光线变化、背景复杂度等影响而对于目标识别准确率存在差异.针对这一现状,提出了一种新的基于时空局部特征和颜色特征的目标匹配方法.利用时空局部特征3-D LSK对待测视频中的运动目标进行行为识别,识别出具有相同行为目标.再结合目标的颜色特征,通过基于区域权重(Weighted Region Matching)的颜色匹配方法来识别出具有相同颜色的目标.对无重叠区域的多个测试视频进行的相关实验表明,该算法能够有效识别出普通场景下的不同目标,对于衣着颜色相近的不同目标也有很高的识别率.     

Characterization of HgCdTe Diodes on Si Substrates Using Temperature-Dependent Current-Voltage Measurements and Deep Level Transient Spectroscopy

Reverse current in diodes can be dominated by generation processes, depending exponentially on temperature according to the rate-limiting step in the generation process. In this report, the current-voltage-temperature (IVT) relationship is analyzed for several midwave infrared and long-wave infrared (MWIR x = 0.295, LWIR x = 0.233) Hg_1−x Cd _x Te (MCT) diodes. The energy varied from diode to diode. At high reverse biases, the energy tends toward the band gap energy. Close to zero bias, the energy ranged from 0.06 to 0.1 eV. Deep level transient spectroscopy (DLTS) showed a broad peak centered at 55–80 K for the MWIR MCT. Comparison of the DLTS spectrum to a simulation based on the energy and capture cross section from a rate window analysis shows that the peak is a band of traps. The capacitance transient amplitude increased as the filling pulse increased from 1 μs to 0.1 s, consistent with capture at a dislocation. A shift to lower temperatures for the peak was also observed when the diodes are cooled under forward bias. The shift is reversible, indicating that the traps consist at least partially of a bistable defect.     

DLTS detection of hole traps in MBE grown ρ-GaAs using schottky barrier diodes

The presence of hole traps has been studied by deep level transient spectroscopy (DLTS) characterization of low carrier densityp-type GaAs grown by MBE on p⁺-GaAs substrates using Al and Co Schottky contacts. The results obtained indicate the presence of several hole traps with energy levels of between 0.06 and 0.65 eV above the valence band in concentrations up to 2 × 10¹²/cm³. Some of these defects,e.g. Cu, are ascribed to system-, source-or substrate-related impurities, but the origin of several other defects is unknown.     

Quantitative oxygen measurements in OMVPE Al x Ga1−x As grown by methyl precursors

Oxygen has always been considered to be a major contaminant in the organo-metallic vapor phase epitaxy (OMVPE) of Al _x Ga_1−x As. Oxygen incorporation has been invoked as a contributor to low luminescence efficiency, dopant compensation and degradation of surface morphology among other deleterious effects. This study presents quantitative measurements of oxygen concentration in nominally high purity Al _x Ga_1−x As. The oxygen concentration was measured as a function of alloy composition, growth temperature, andV/III ratio. Quantitative secondary ion mass spectroscopy (SIMS) measurements were used to determine the oxygen content as well as the carbon concentration in the film. The oxygen concentration increases with decreased growth temperature and V/III ratio while increasing superlinearly with Al content in the epitaxial layer.     

Electrical characterization of self-assembled In0.5Ga0.5As/GaAs quantum dots by deep level transient spectroscopy

We have investigated electron emission from self-assembled In_0.5Ga_0.5As/GaAs quantum dots (QDs) grown by molecular-beam epitaxy (MBE). Through detailed deep level transient spectroscopy comparisons between the QD sample and a reference sample, we determine that trap D, with an activation energy of 100 meV and an apparent capture cross section of 5.4×10⁻¹⁸ cm², is associated with an electron quantum level in the In_0.5Ga_0.5As/GaAs QDs. The other deep levels observed, M1, M3, M4, and M6, are common to GaAs grown by MBE.     

深亚微米SOC芯片分层设计方法

根据深亚微米SOC设计的特点和需求,提出了一种新的基于模块的全芯片分层设计方法,它把系统架构、逻辑设计以及物理实现有机结合到一起.通过渐进式时序收敛完成芯片的层次规划,并最终达到一次实现芯片级的时序收敛,大大提高了深亚微米SOC设计的效率,并在实际设计之中得到了有效验证.