分析半导体工艺设备中可编程逻辑器件

本文介绍在半导体工艺设备中常见的可编程逻辑器件，以及分析电器板中的可编程逻辑器件，写出已加密GAL器件的逻辑功能。     

A Coded Modulation Scheme for Deep-Space Optical Communications

A coded modulation scheme for deep-space optical communications is studied, which is a serial concatenation of an outer low-density parity-check (LDPC) code, an interleaver, a bit-accumulator, and pulse-position modulation (PPM). It is referred as LDPC-APPM. It is decoded with an iterative demodulator-decoder using standard turbo-decoding techniques. Simulation results show that the LDPC-APPM with an outer LDPC code of medium code length suffers a loss of about 0.7 dB at a bit-error rate of relative to the serially concatenated PPM (SCPPM) of similar parameters, which consists of the serial concatenation of an outer convolutional code, an interleaver, a bit-accumulator, and PPM; however, it has better code rate flexibility especially for high rates and simpler implementation structure than SCPPM. Further, it can achieve better performance than the LDPC-PPM of the same rate and length, which consists of the serial concatenation of an LDPC code and PPM.     

基于决策树的EPG体验异常原因定位

用户体验的提升一直是IPTV的运维重点。然而,运营商IPTV组网相对复杂,涉及机顶盒、接入网、EPG页面、EPG服务器、媒体服务器等多个环节和调度链路,一旦发生异常,运维人员需排查各环节的监控指标,凭经验定位引起异常的原因。该运维模式专业性强、效率低下,无法快速止损。为解决上述运维痛点,基于大数据技术,采用决策树对EPG体验数据建模,根据决策树模型的决策规则,快速定位异常原因。现网中,决策树模型能够准确快速定位EPG体验的异常原因,为辅助运维人员指明排查方向,提高运维效率。     

从OFC2001看世界光纤通信的新发展

文中报道了OFC2001会议的概况,并从光纤传输系统、宽波段光放大器、可调谐光源技术,阵列波导光栅、偏振模色散的研究和补偿技术五个方面来介绍光纤通信的最新发展。     

迅速崛起的亚太光纤市场

本文归纳分析出亚太光纤市场的两个显著特点，介绍了亚太地区光通信发展水平，以及亚太各国和地区间的光通信合作，指出亚太光纤市场得以迅速发展的主要原因。     

Al_xGa_(0.51-x)In_(0.49)P光学性质的研究

用MOCVD方法在GaAs衬底上生长了AlGaInP的本征及掺Si或掺Mg三个样品。用椭偏光谱法测量了样品在室温下可见光区的光学常数 ,并求其介电函数的三级微商谱。用三点比例内插法分析介电函数的三级微商谱 ,精确地得到样品的带隙Eg、Eg+Δ0 以及Eg 以上成对结构跃迁的能量位置 ,并对其结果加以分析。同时与沟道分析等方法相结合对材料的性能进行了鉴定。     

Electroluminescence and Laser Emission of Soluble Pure Red Fluorescent Molecular Glasses Based on Dithienylbenzothiadiazole

Soluble molecular red emitters 1a / 1b are synthesized by Stille coupling from 2‐(3,5‐di(1‐naphthyl)phenyl)thiophene precursors. The compounds show emission maxima at ca. 610 nm in CH₂Cl₂ solution and 620 nm in solid films. Replacing the n‐hexyl substituent by 4‐sec‐butoxyphenyl produces a marked increase of glass transition temperature (T_g) from 82 °C to 137 °C and increases the solubility in toluene and p‐xylene, thus improving the film‐forming properties. Cyclic voltammetry shows that the compounds can be reversibly oxidized and reduced around +1.10 and ?1.20 V, respectively. A two‐layered electroluminescent device based on 1b produces a pure red light emission with CIE coordinates (0.646, 0.350) and a maximal luminous efficiency of 2.1 cd A^?1. Furthermore, when used as a solution‐processed red emitter in optically pumped laser devices, compound 1b successfully produces a lasing emission at ca. 650 nm.     

基于非对称形变的全光纤宽阻滞滤波器的制作

本文提出的基于长周期光纤光栅（LPFG）的全光纤宽阻带滤波器的制做方法，基本原理是在光纤纤芯中引入周期性的非对称形变，从而使光纤纤芯的折射率发生周期性变化；提出了两种实现光纤纤芯非对称形变的方法，进而制做出阻带中心波长分别为1310nm和1550nm的全光纤宽阻带滤波器插入损耗分别小于0.8dB和1.4dB，后向反射损耗小于-70dB。这样的器件可用于提高WDM系统的隔离度。     

大功率半导体激光器驱动电源的设计

设计一种大功率半导体激光器的驱动电源。恒稳电流范围为 0～ 10 A,稳流精度为 1m A,脉冲输出电流频率为 10 KHz,脉冲电流的占空比为 1∶ 10 ,脉冲电流幅值为 0～ 10 A可调     

网格应用发展现状与分析

介绍了网格应用的四个主要领域。包括分布式超级计算，信息集成、数据密集型计算和分布式仪器系统,并对这些网格应用的特点进行了分析,对网格应用的发展方向进行了展望。