浅析分组传送网中TD-SCDMA基站同步解决方案

通过对TD—SCDMA移动网络的同步需求及目前主要同步技术的分析,比较几种TD—SCDMA基站同步解决方案,可以看出采用支持IEEE1588V2地面传送的OTN＋PTN组网方案能较好地满足TD—SCDMA网络时间同步要求,具有一定的推广一价值。     

三峡下游引航道工程基础开挖监理实践

介绍了监理工程师对爆破作业实行全方位、全过程控制 ,并在工作实践中不断总结经验 ,优化爆破参数 ,在质量和安全控制方面取得的显著效果。     

智能光网的关键技术

分析了作为下一代光网络的发展方向——智能光网(ION)的组成结构与关键技术，并结合最新技术进展，重点给出了作为智能光网的典型代表——自动交换光网络(ASON)的网络性能与功能特点，说明了网络演进中要注意解决的问题和下一步的发展方向。     

MEMS光开关应用于机群系统光互连网络

建立了千兆位传输结构的高性能光互连网络 ,以提高计算机机群系统的网络性能 .利用MEMS 4× 4光开关和具有硬件路由功能的光互连网络PCI总线接口卡构成光互连链路 .光信号传输速率达 1Gbits/s以上 .基于MEMS的全光无堵塞光开关减少了光 电转换 ,开关方式与光信号的波长、速率和数据格式无关 .利用这种网络结构 ,可以最大限度地减少网络延迟和网络通信开销 ,提升了机群系统的总体性能 .利用MEMS 8× 8光开关设计了星型环型混合拓扑的光互连网络 .采用了具有硬件路由功能的光互连网络接口卡 ,并以Ethernet为控制网络实现了对MEMS光开光的动态配置 .分析并测试了光互连网络的通信性能 :峰值数据传输率可达 1Gbits/s ;数据量在 3Mbytes以上时 ,网络整体性能明显提高     

ZigBee网络中关于RSSI测距技术研究

通过调研分析各种无线网络优缺点,根据系统特点选择使用ZigBee网络设计节点,软硬件结合实现网络通信功能,编写软件通过三个不同等级的功率、多次测量、不同范围的测量实现了RSSI(Received Signal Strength Indictor)值的提取.分析得出在不同测量距离内,传输损耗值是不同的,测量距离越小,损耗值越低,反之越高.通过测量值得出的时间功率图证明了ZigBee是有效的、适合短距离、节点较少的一种距离测量的无线组网通讯技术.     

Internet of Things Based Solutions for Transport Network Vulnerability Assessment in Intelligent Transportation Systems

Intelligent Transportation System (ITS) is essential for effective identification of vulnerable units in the transport network and its stable operation. Also, it is necessary to establish an urban transport network vulnerability assessment model with solutions based on Internet of Things (IoT). Previous research on vulnerability has no congestion effect on the peak time of urban road network. The cascading failure of links or nodes is presented by IoT monitoring system, which can collect data from a wireless sensor network in the transport environment. The IoT monitoring system collects wireless data via Vehicle-to-Infrastructure (V2I) channels to simulate key segments and their failure probability. Finally, the topological structure vulnerability index and the traffic function vulnerability index of road network are extracted from the vulnerability factors. The two indices are standardized by calculating the relative change rate, and the comprehensive index of the consequence after road network unit is in a failure state. Therefore, by calculating the failure probability of road network unit and comprehensive index of road network unit in failure state, the comprehensive vulnerability of road network can be evaluated by a risk calculation formula. In short, the IoT-based solutions to the new vulnerability assessment can help road network planning and traffic management departments to achieve the ITS goals.     

Anisotropic Quantum Transport through a Single Spin Channel in the Magnetic Semiconductor EuTiO3

Magnetic semiconductors are a vital component in the understanding of quantum transport phenomena. To explore such delicate, yet fundamentally important, effects, it is crucial to maintain a high carrier mobility in the presence of magnetic moments. In practice, however, magnetization often diminishes the carrier mobility. Here, it is shown that EuTiO₃ is a rare example of a magnetic semiconductor that can be desirably grown using the molecular beam epitaxy to possess a high carrier mobility exceeding 3000 cm² V⁻¹ s⁻¹ at 2 K, while intrinsically hosting a large magnetization value, 7 μ_B per formula unit. This is demonstrated by measuring the Shubnikov–de Haas (SdH) oscillations in the ferromagnetic state of EuTiO₃ films with various carrier densities. Using first-principles calculations, it is shown that the observed SdH oscillations originate genuinely from Ti 3d-t_2g states which are fully spin-polarized due to their energetical proximity to the in-gap Eu 4f bands. Such an exchange coupling is further shown to have a profound effect on the effective mass and fermiology of the Ti 3d-t_2g electrons, manifested by a directional anisotropy in the SdH oscillations. These findings suggest that EuTiO₃ film is an ideal magnetic semiconductor, offering a fertile field to explore quantum phenomena suitable for spintronic applications.     

光纤中基于SBS实现慢光的数值研究

通过运用带有预测.校正的隐格式有限差分法对基于光纤的受激布里渊散射耦合方程组进行了数值求解.在增益0～16范围内考察了布里渊增益系数、增益带宽以及有效模面积对时间延迟和脉冲展宽的影响.结果表明,较小的增益系数和增益带宽、较大的有效模面积使得Stokes信号具有更大的饱和增益值,相应的时间延迟也较大.在固定泵浦功率并保证增益参数在小信号范围的情况下,时间延迟及脉冲展宽因子随着增益系数的增加而增加,但随着增益带宽以及有效模面积的增加而减少.     

磁流体的光学特性及其在光电信息传感领域中的应用

详细介绍了磁流体的光学性质,包括磁流体的热透镜效应、磁光效应.磁流体折射率的可控性以及磁致分色效应.由于磁流体的光学性质具有可调谐性,这为磁流体在新型光子器件与光纤传感器的设计和研究提供了新原理.新材料.论述了应用磁流体设计的多路复用器、光开关、光纤调制器、可调谐磁流体光栅与可调谐滤波器,以及基于磁流体的光纤电流传感器原理和结构.     

主动配电网规划方法研究

分布式电源接入配电网后对供电可靠性、电压分布、网损均产生一定影响,传统配电网规划方法已无法适用。构建主动配电网（active distribution network,ADN）规划设计体系结构,从电网现状、负荷预测等方面制定主动配电网规划内容,重点研究基于分布式电源风险度出力置信区间的源网荷一体化平衡及网荷协同性规划方法,最后给出主动配电网电气校验方法,验证方案制定的合理性。     

碳纤维复合材料在空间光学相机中的应用研究

随着空间光学相机口径的增大,相机的质量也随之增加,要满足轻质量、高分辨的空间相机要求,碳纤维复合材料是一个很好的选择。根据空间光学相机的精度、稳定性要求,对比了空间相机中常用材料的性能,分析了碳纤维复合材料应用于空间光学相机的三大优势和两大劣势,介绍了国内外碳纤维复合材料在空间相机中的应用概况和水平,指出了碳纤维复合材料在空间光学相机中的广泛应用必然是未来空间光学相机的发展方向。