应用于OTDR测试的光纤光栅反射器

本文阐述了反射器在PON的OTDR测试诊断系统中的作用及其必要性,探讨了光纤光栅反射器方案的应用特点、与介质薄膜滤波器对比的优势及在国际市场上的应用情况,并介绍了目前光纤光栅反射器在成本方面的突破。     

长江和畅洲段的河床演变和水体的环境容量

长江和畅洲段河床演变造成南汊分流比逐年下降，本文对不同分流比情况下的污染带分布和断面平均深度进行了计算，其结果表明：随着分流比的下降，南汊水体的环境容量减少，水质污染加剧，从水体环境保护方面定量论证该江段河道整治工程的重要性。     

秭归水田坝等三条断裂关系及孕震强度评价

鄂西种秭归盆地是长江三峡地区重要的构造单元之一，盆地东侧水田坝断裂与其南部龙王冲断裂、北部新华断裂，经分析不属同一基底构造体系。尽管各断裂近期活动不甚明显，按活动断裂评价标准，均不属工程活动断裂，但不能排除发生中强地震的危险性。用经验公式法估算的最大构造地辱震级，水田坝断裂为５．５级、龙王冲断裂为６．０级、新会断裂为６．５级。     

海上舰艇编队遭遇战中的通信对抗战术初探

海上舰艇编队遭遇战中的通信对抗 ,是涉及到海战中一方能否有效控制对方信息互通、能否有效阻断其编队的海上指挥与控制的重要作战手段。以红、蓝双方舰艇编队间展开海上遭遇战为研究对象 ,着眼于对抗战术的作战使用 ,探讨海上舰艇编队间实施通信对抗战术的理论基础和战术配置 ,对于未来海上遭遇战中进行通信对抗、采取有效战术措施具有一定的指导意义。     

一种多普勒盲区下的航迹片段关联方法

在多目标跟踪过程中,机载预警雷达固有的多普勒盲区容易引起目标航迹中断和重起批,形成大量航迹片段,从而增加雷达情报分析的难度。基于此,提出了一种改进的多普勒盲区下的航迹片段关联方法。在传统基于二维分配的关联方法基础上,将多普勒盲区和目标类别信息并入到航迹片段关联的各个环节。预处理阶段采用盲区滤波算法对“老”航迹进行预测,粗关联阶段增加径向速度作为关联信息,二维分配阶段,利用目标类别信息修正分配代价函数。仿真结果表明：在复杂多目标环境且存在多普勒盲区的条件下,该方法航迹中断数较传统方法有明显下降,航迹寿命有明显提升。     

Improved video streaming using MSVC and nonoverlapping zone routing multipath propagation over MANETs

Providing real‐time video streaming in mobile ad hoc networks is difficult because of the time‐dependent channel status and stringent service requirements. The currently existing route request‐reply–based multihop overlay networks cause considerable control overheads in video transmission resulting in loss of data and communication breakdown. Such networks are more suitable to nonstreaming video applications rather than to time‐sensitive video streaming applications. Therefore, a powerful mechanism needs to be adopted to handle the channel failures amicably and reduce latency effectively in time critical video streaming applications over mobile ad hoc networks. In order to be resilient to the channel failures and reduce latency in such applications, 2 strategies, namely, multistate video coding and 2‐tier–based nonoverlapping zone routing multipath propagation through directional antennas have respectively been incorporated. The performance of the proposed nonoverlapping zone routing multipath propagation system is compared with those of the existing multicast zone routing and zone‐based hierarchical link state routing protocols with parameters average end‐to‐end delay, routing overhead and packet delivery ratio using NS 2.34. The simulation results show that latency and resilience get considerably improved. Finally, the video quality of the proposed work has been verified by subjective and objective video testing methods.     

Microstructure evolution and corrosion resistance in simulated CGHAZ of X80 high-deformability pipeline steel

In this study, the microstructure evolution and corrosion resistance in 0.5M Na₂CO₃-1 M NaHCO₃ solution of X80 high-deformability (X80HD) pipeline steel coarse-grained heat-affected zone (CGHAZ) with several heat input levels were investigated. It is shown that the microstructure of CGHAZ changes from bainite ferrite to granular bainite as the heat input increasing. In addition, the corrosion resistance and the stability of passive film of base material are better than those of CGHAZ with several heat input levels. Too small or too big heat input is inadvisable and better corrosion resistance of CGHAZ is attained when heat input is 30kJ/cm.     

衍射波长10.6μm的计算全息光栅扫描器研究

给出了圆筒型和圆盘到计算全息光栅扫描器的位相方程、条纹位置方程及参数结构方程式,并由此设计和制作了用于波长λ＝１０．６μｍ的圆盘型反射式计算全息光栅扫描器,在实验中重点解决了零点漂移和波称λ＝１０．６μｍ的激光为不可见光的问题,最后对扫描特性进行了分析。     

Downlink Capacity Analysis of Collaborative Crossed Timeslots in CDMA TDD Systems

Traffic asymmetry between uplink and downlink is expected to be a remarkable 3G characteristic in cellular mobile multimedia communications. CDMA system with TDD is a good solution to this traffic asymmetry. However, the level of traffic asymmetry may be significantly different from a cell to another cell. To tackle this problem and to support the traffic hot spot, crossed slots are examined. The use of crossed slots is restricted within a certain range of a cell by investigating the inter-cell interference and the maximum planned load factor. We examine the radius of inner zone and discuss the capacity of downlink crossed slots for various neighbor cell environments. Computational results show that the capacity increase in the target cell is outstanding by reducing the service range of neighbor cells. When all six neighbors reduce their service range by 20%, the capacity at target cell crossed slot is increased by 35%. Monte Carlo simulation is performed with large scale fading to verify the numerical analysis.