波分多路应用引伸至市内网

本文首先简述从时分多路发展至波分多路的具体过程。接着，详细说明时分多路系统在途径主干线中上的应用，以及最近引伸至市内网和接入网的应用。于是简单提到波分多路技术从点至点系统进而应用于全光通信网。又简述波分多路在海底光缆的应用。     

Multi-heterojunction large area HgCdTe long wavelength infrared photovoltaic detector for operation at near room temperatures

This paper describes a new multi-heterojunction n ⁺pp photovoltaic infrared photodetector. The device has been developed specifically for operation at temperatures of 200–300K in the long wavelength (8–14 μm) range of the infrared spectrum. The new structure solves the perennial problems of poor quantum efficiency and low dynamic resistance found in conventional long wavelength infrared photovoltaic detectors when operated near room temperature. Computer simulations show that devices with properly optimized multiple heterojunctions are capable of achieving the performance limits imposed by the statistical nature of thermal generation-recombination processes. In order to demonstrate the technology, multiple heterojunction devices have been fabricated on epilayers grown by isothermal vapor phase epitaxy of HgCdTe and in situ As p-type doping. The detector structures were formed using a combination of conventional dry etching, angled ion milling, and angled thermal evaporation for contact metal deposition. These multi-junction n ⁺pp HgCdTe heterostructure devices exhibit performances which make them useful for many applications. D* of optically immersed multiple heterostructure photovoltaic detectors exceeding 10⁸cmHz^1/2/W were measured at λ=10.6 μm and T=300K.     

Growth and characterization of inTISb for IR-detectors

Epitaxial In_1-xTl_xSb films with compositions up to x = 0.1 have been demonstrated using the metalorganic chemical vapor deposition technique on InSb and GaAs substrates. A specially designed high-temperature source delivery system was used for the low vapor pressure cyclopentadienylthallium source. Tl-compositions in the deposited films were measured by Rutherford backscattering spectroscopy which confirmed the incorporation of up to 10% Tl. Room temperature infrared transmission spectra of InTISb exhibited considerable absorption beyond 7 μm. Photoconductive detectors were fabricated in InTISb films grown on semi-insulating GaAs. Spectral response measurements showed substantial photoresponse at 8.5 to 14 μm. In spite of the large lattice-mismatch (≈14%) between InTISb and GaAs, photoconductive detectors exhibited black-body detectivities (D^* _bb) of 5.0 × 10⁸ cm-Hz^1/2W⁻¹ at 40K.     

Wind speed variability across the UK between 1957 and 2011

By using surface data from 57 UK meteorological stations, a national [British Atmospheric Data Centre (BADC)‐57] and regional wind index for the UK has been calculated for the period 1983–2011. For a subset of seven stations, an additional national index (BADC‐7) has been calculated for the period 1957–2011. The indices show an annual variability of 4% over their respective periods, corresponding to a variation in typical wind turbine capacity factor of 7%. These indices are compared with indices calculated from other sources, namely an index generated using a gridded dataset of observed values interpolated across the UK, an index calculated from an area bounding the UK using the ERA‐40 re‐analysis dataset, indices calculated from bilinear interpolation of the ERA‐40 re‐analysis dataset to the 57 and 7 stations and another independent UK wind index. The indices show variation in trends, with all showing some level of decline with the exception of that generated using the ERA‐40 re‐analysis dataset averaged over the UK, which shows a significant increase. The various indices show varying degrees of agreement with correlation coefficients, after trends are removed, ranging between 0.611 and 0.979. The effect of changes in site exposure, instrument bias and measuring height was considered for the BADC‐7 and BADC‐57 indices. The change in instrument measurement height appears to have a significant biasing effect, and it is likely that this along with changes in exposure at urban sites has caused the decline in annual wind speeds observed for some of the indices. There does not appear to be evidence for significant changes in large‐area (mesoscale) surface roughness. The correlation between annual mean wind speeds at the seven surface station sites used to calculate the BADC‐7 index is seen to be quite weak, indicating very localized variations in inter‐annual variability. When regional differences in the index are investigated, it is seen that wind speeds show a very slight decline across the UK in all regions except the south‐east, which shows a slight increase. The greatest decrease is seen in the north‐west. These changes are in the same direction as the tentative predictions given by climate models for future changes in wind speed across the UK, although the uncertainty is large given the large degree of inter‐annual variation. Copyright © 2013 John Wiley & Sons, Ltd.     

FPGA准实时寿命损耗评价系统的验证试验设计

为验证已建立的现场可编程门阵列(FPGA)器件准实时寿命评价系统的工程合理性,进行了加速寿命试验的设计.验证试验的设计,考虑不同型号之间的可靠性差异,针对特定型号的Xilinx XCV600 FPGA样本,能够定位样本内部具体失效部位.针对FPGA高可靠性的特点,施加温度、电压和频率3种加速应力;针对FPGA使用环境多变的特点,构建了整套载荷数据跟踪与处理流程.试验方案通过硬件和软件系统实现,硬件系统进行FPGA工作环境的加载及准实时工作情况数据的采集,软件系统基于电迁移失效机理对采集到的数据进行处理得到寿命信息,将试验与预测结果进行比对完成验证.实践表明了该试验设计的可实施性,确认了部分系统预测结果的准确性.     

用于高分辨率光谱仪的离轴三反射镜光学系统的设计

面对空间遥感,尤其在目标特性的精细化识别中,要求成像光谱仪具有高灵敏度、高光谱分辨率与高能量通过力等优点．在同轴三反射光学系统的基础上,采用视场离轴方式,设计了一个三镜无遮拦全反射光学系统．次镜和光阑重合,无中间像,实现了高分辨率、大视场、长焦距的要求．光学系统的基本参数为：焦距f’=1600mm,视场角为2w=18°×0．148°,相对孔径为1／10,3个反射面均为二次曲面．设计结果表明,成像质量接近衍射极限,用此方法设计的光学系统在航天遥感领域具有很好的应用前景．     

Au线键合中"塌线"问题的研究

目前,在半导体闪存多芯片的金线键合工艺中,为满足堆叠芯片不断增加等结构需要,键合线弧要求更低、更长,制造工艺变得相对更加复杂。针对生产过程中常遇到的塌线问题,通过对金线键合工艺中线弧形成动作的过程分析,以金线弹动现象为线索,探究了生产过程中塌线问题产生的原因,并给出了相应解决方案。经过此研究,长线键合的生产工艺能力得到加强,其成果对新封装产品的研发及基板设计具有有益的参考价值。     

一种面向多媒体SOC的微状态低功耗设计方法

针对目前移动多媒体SOC设计中日益突出的功耗问题,结合传统的动态功率管理和动态频率调整中的负载预测和反馈控制两种方法,同时利用系统中各类IP和设计模块的可配置特性,提出了一种基于微状态的面向多媒体应用SOC的系统级低功耗设计方法。该方法以F-ARIMA过程作为负载预测模型,以最后期限缺失率作为反馈控制信号来实现系统实时动态在微状态之间进行切换,从而尽可能使得负载能均匀分布于运行期间。该方法在保证多媒体服务质量(QOS)的同时,有效降低了系统功耗。     

生命探测雷达环境动目标的干扰抑制研究

生命探测雷达在实际探测中,由于环境中动目标的存在而对探测系统造成一定的干扰,致使雷达的探测准确性降低。本文搭建了基于双天线的连续波生命探测雷达实验平台,提出了将互相关无偏估计方法应用于生命探测过程中的环境动目标干扰抑制,并进行了实际探测实验,给出了结果。所采信号及处理结果表明该方法适用于生命探测雷达环境中动目标的干扰抑制。     

基于小波变换微弱生命信号提取的研究

利用小波变换研究微弱生命信号提取问题,简要介绍Mallat算法,采用小波阈值去噪法对强噪声背景下微弱生命信号进行去噪研究,并简要介绍阈值的估计方法,通过实例,利用MATLAB仿真验证小波变换在微弱生命信号的提取中可取得良好的效果。