OPLC电缆成缆外径的计算

详细介绍了光纤复合低压电缆(OPLC)的功能及电缆结构,通过对电缆结构的分析建立了OPLC电缆成缆外径的数学计算模型,并结合MathCAD数学计算软件,对3+1+1芯结构OPLC电缆的成缆外径进行了精确计算。     

OTN技术在传统波分中的应用

简要介绍了光传送网（OTN）技术相对于传统波分系统的优点,并结合骨干传输网工程的建设对OTN电交叉在传统波分系统中的应用进行了论证。     

模拟燃气射流场的莫尔偏折显示及定量测试

在实验室条件下,制作了模拟膛口高速射流的装置.应用莫尔偏折法对双基发射药膛口燃气射流场进行了显示及定量测试研究.整套莫尔显示及测试系统由激光光源、莫尔偏折仪、CCD、监视器、图像存储和处理系统以及586计算机等组成.应用莫尔偏折层析技术定量计算并再现了膛口双基发射药燃气射流场的温度分布.     

In Situ Study of Nanostructure and Electrical Resistance of Nanocluster Films Irradiated with Ion Beams

An in situ study is reported on the structural evolution in nanocluster films under He⁺ ion irradiation using an advanced helium ion microscope. The films consist of loosely interconnected nanoclusters of magnetite or iron‐magnetite (Fe‐Fe₃O₄) core‐shells. The nanostructure is observed to undergo dramatic changes under ion‐beam irradiation, featuring grain growth, phase transition, particle aggregation, and formation of nanowire‐like network and nanopores. Studies based on ion irradiation, thermal annealing and electron irradiation have indicated that the major structural evolution is activated by elastic nuclear collisions, while both electronic and thermal processes can play a significant role once the evolution starts. The electrical resistance of the Fe‐Fe₃O₄ films measured in situ exhibits a super‐exponential decay with dose. The behavior suggests that the nanocluster films possess an intrinsic merit for development of an advanced online monitor for fast neutron radiation with both high detection sensitivity and long‐term applicability, which can enhance safety measures in many nuclear operations.     

注入条件对SIMOX材料的影响

利用ＲＢＳ和ＴＥＭ技术分析研究了不同注入剂量、注入方式（单重注入，多重注入）对ＳＩＭＯＸ材料各层结构的影响，特别着重研究了Ｓｉ／ＳｉＯ２界面过渡区受注入条件的影响。结果表明，在注入剂量相同的情况下，多重注入不仅能改善顶层单晶、ＳｉＯ２绝缘层的质量，而且能显著减小Ｓｉ／ＳｉＯ２界面过渡区宽度。     

MPC在大功率交流牵引中的应用

目前由交-直-交电压型功率变换器和异步牵引电动机所构成的交流传动系统，已成为世界电力机车、电动车组和城轨车辆电传动技术的主流，而交流传动的核心单元是牵引变换器。本文对原ADtranz公司所设计的模块化功率变换器-MPC的技术特征进行了归纳和分析，最后指出随着电力电子技术和微处理器技术的发展，模块化及分布式控制系统已经成为功率变换器的发展趋势。     

利用脉冲复制环提高纳秒脉冲单次测量的动态范围

提出了一种提高纳秒光脉冲单次测量动态范围的方法,其中光纤脉冲复制环用来产生时域上幅度呈指数递减的脉冲复制串,有效环增益为0.955。经软件补偿脉冲复制串使其具有相同的幅度,然后累加平均前18个脉冲,能够将注入的单发纳秒光脉冲动态范围提高2.74倍,这样就可以实现利用光电探测管和示波器对100:1高对比度的惯性约束核聚变(ICF)脉冲测量。     

Novel Direction Findings for Cyclostationary Signals in Impulsive Noise Environments

We consider the problem of direction-of-arrival (DOA) estimation for cyclostationary signals in impulsive noise modeled as a complex symmetric α-stable (SαS) process. Since the DOA estimation based on second-order cyclic statistics degrades seriously in an α-stable distribution noise environment, we define a novel pth-order cyclic correlation by fusing the fractional lower order statistics and second-order cyclic correlation. After briefly introducing the statistical characteristics of pth-order cyclic correlation and building the extended data model, we first propose a novel extended pth-order cyclic MUSIC algorithm (EX-POC-MUSIC) by exploiting both pth-order cyclic correlation and pth-order cyclic conjugate correlation. The algorithm allows us to select desired signals and to ignore interference in the communication system. Second, in order to increase the resolution capabilities and the noise robustness significantly, an improved EX-POC-MUSIC algorithm called the extended pth-order cyclic Root-MUSIC (EX-POC-RMUSIC) algorithm is also presented. This algorithm has all the merits of the EX-POC-MUSIC algorithm, and it is also a fast DOA estimation algorithm because it avoids spatial spectrum searching. Under some conditions, both proposed algorithms are able to handle more sources than the number of sensors. Simulation results strongly verify the effectiveness of the two algorithms.     

GPRS与内容计费

随着数据业务的快速发展,业务种类越来越丰富。丰富的业务向其承载网GPRS提出了内容计费的要求。本文针对GPRS实现内容计费的方案进行了讨论,提出了GGSN改造和WAP网关改造两个方案并对两个方案进行了对比分析。