2.5Gb/s光外调制器及驱动器

文章对光外调制作了原理及实验上的分析,着重研究作为驱动器的大功率宽带放大器。对２．５Ｇｂ／ｓＮＲＺ伪随机码对放大器的低端截止频率和高端截止频率的要求进行了理论分析。提出并实验了几种放大器高频补偿技术,取得了好的效果。为满足输入输出阻抗为５０Ω的要求采用了共面波导计算方法,以确定印刷电路板导线尺寸。最后对光外调制器输出波形进行了测试。     

光纤激光传感技术及其应用

超高灵敏度的信号探测在石油勘探、地震预报和安全监测等领域都具有重要的应用价值.近年来出现了一种以分布反馈(DFB)光纤激光器为传感元件的新一代光纤传感器,它具有尺寸小、输出激光信号极窄的光谱线宽和极低的噪声等优势,与高分辨率波长解调技术结合可以达到极高的探测灵敏度.介绍了在光纤激光传感技术及其应用技术方面的研究进展,包括线宽仅为3 kHz、尺寸仅为3.6 cm的窄线宽低噪声DFB光纤激光器的研制及其测试,波长分辨率达3.5×10~(-7) pm/Hz~(1/2)的超高分辨率波长解调系统,基于密集波分复用的光纤激光传感网络,以及相关技术在水声和地震波探测中的应用研究.     

光子晶体光纤的原理、应用和研究进展

光子晶体光纤（POF）与普通光纤在光纤结构、单模特性、色散特性和非线性特性等方面有着显著的差别。本文将简要分析PCF的管理，并探讨其重要特性以及应用价值 ，最后回顾了近来PCF的研究进展。     

掺铒光纤放大器放大高速ps半导体激光脉冲的研究

理论与实验研究了掺银光纤放大器放大高速PS半导体激光脉冲的行为，给出了放大高速光脉冲时放大器的增益特性与光脉冲占空比之间的关系，占空比越大，输出光脉冲的峰值功率越小，理论与实验结果较好地一致。     

基于Android平台飞机罗盘校准系统软件的实现

为了解决了航空磁罗盘校准精度、效率低下问题,设计一套基于Android系统的面向各种飞机罗盘校准系统,此系统由座舱显控单元、牵引车显控单元、基准罗盘单元等组成,各单元通过WIFI无线网络进行通讯。对飞机上磁罗盘、光纤捷联航姿、无线电罗盘三方面进行精准校准。校准设备精度为不低于0.5°,设备供电采用锂电池供电工作时间不小于8小时。校准首次采用8点校准、12点校准两种校准模式,大大提高了罗盘校准精度。此系统对罗盘校准场地要求低,制造成本低、操作界面清晰,逻辑结构简单、科技含量高。通过对多机型的罗盘校准,确定比传统罗盘校准用时短、效率高,劳动强度低,达到很好的预期。     

Behavior of Pultruded Fiber-Reinforced Polymer Beams Subjected to Concentrated Loads in the Plane of the Web

Results of the behavior of pultruded fiber-reinforced polymer (FRP) I-shaped beams subjected to concentrated loads in the plane of the web are presented. Twenty beams with nominal depths from 152.4 to 304.8?mm were tested in three-point bending with a span-to-depth ratio of four. Load was applied to the top flange directly above the web—12 without bearing plates and 8 with bearing plates of varying width and thickness. All test specimens failed with a wedgelike shear failure at the upper web-flange junction. Finite-element results support experimental findings from strain gauge and digital image correlation data. Bearing plates increased beam capacity by 35% or more as a function of bearing plate width and thickness. Bearing plates increased average shear stress in the web at failure from 17.4 to 27.2?MPa—below the accepted value of in-plane shear strength (69?MPa). A design equation is presented, and predicted capacities are compared with experimental results. The average value of experimental capacity to predicted capacity is 1.12 with a standard deviation of 0.11 and coefficient of variation (COV) of 0.10 for sections up to 304.8?mm deep.     

A statistical micromechanical model of multiple cracking for ultra high toughness cementitious composites

A new statistical micromechanical model of multiple cracking is proposed in which a general expression of the fiber bridging stress laws in the crack plane is established. In this model, the random distribution properties of fibers are considered. And the Weibull function is adopted to represent the flaw size distribution. The relationships of stress versus strain and crack width versus strain are proposed. The formulas of the crack width, crack space, strain capacity and fracture energy density at the end of multiple cracking processes are also deduced. The validity of the proposed model was demonstrated by experimental results.     

Swelling behaviour of a geofiber-reinforced expansive soil

This paper reports the results of laboratory study performed on expansive soil reinforced with geofibers and demonstrates that discrete and randomly distributed geofibers are useful in restraining the swelling tendency of expansive soils. Swelling characteristics of remoulded expansive soil specimens reinforced with varying fiber content (f = 0.25% and 0.50%) and aspect ratio (l/b = 15, 30 and 45) were studied. One-dimensional swell-consolidation tests were conducted on oedometer specimens. Reduction in heave and swelling pressure was the maximum at low aspect ratios at both the fiber contents of 0.25% and 0.50%. Finally, the mechanism by which discrete and randomly distributed fibers restrain swelling of expansive soil is explained with the help of soil–fiber interaction.     

两种在HIRFL-CSR中使用的光纤通信适配器

介绍了两种针对HIRFL-CSR控制特点,自主开发设计的光纤通信适配器.包括设计思路、工作原理、硬件组成及应用范围.如何利用这两种光纤适配器远程控制具备RS232或RS485接口的仪器设备.在工程中应用这两种适配器和光纤替代RS485总线解决了通信干扰问题,满足了工程控制要求.