Tunnel transition mechanism support all types of NAT users

Through the analied of current tunneling mechanism,a more efficient and applicable tunneling mechanism called TrNAT based on TSP to face different scenarios was proposed.Optimization of the communications between NAT users was achieved with ideology of MIPv6.Then,Shim6 was utilized to realize route redundancy and also improved the route aggregation of 6 to 4 tunnel.Finally,TrNAT tunneling mechanism was implemented on Linux kernel and validated by experiments.     

虚拟专用网及其关键技术

ＶＰＮ（Ｖｉｒｔｕａｌ Ｐｒｉｖａｔｅ Ｎｅｔｗｏｒｋ,虚拟专用网）是目前计算机网络技术发展的新热点,是一种新的专用通信网的组网方式。首先讨论了ＶＰＮ的基本概念、功能、实现途径及其基本构成,然后重点讨论了ＶＰＮ的关键技术,最后展望了ＶＰＮ的发展前景。     

一种新型的STM探针

以普通的石英光纤为材料，用熔拉腐蚀复合的方法制备出nm量级的光纤探针，而后在针尖表面镀上数十nm厚的金属膜，达到导电性，使其能传导隧道电流，从而研制出一种新型的扫描隧道显微镜（STM）光纤隧道探针，在STM上取得了比较理想的实验结果。本文将光纤隧道探针与金属隧道探针作了比较，并对其性能作了分析。     

平板光子晶体的全反射遂穿及其偏振特性

为了研究1维平板光子晶体的全反射隧穿效应,采用传输矩阵法进行了TE波和TM波大于全反射角入射1维平板光子晶体时所产生的全反射隧穿效应及其偏振特性的研究。结果表明,TE波和TM波的全反射隧穿峰的频率随平板厚度的增加向低频方向移动;全反射隧穿峰的频率随光子晶体的周期光学厚度的增加而减少。这一结果对认识光子晶体的传输特性是有帮助的。     

IPv6核心网络隧道设计与验证

针对IPv6核心网络的部署,分析了IPv4穿越IPv6核心网络的应用需求,给出了IPv4 over IPv6隧道技术方案设计,重点介绍了IPv4 over IPv6隧道技术的软件组成、控制流程和数据流程,以及具体的软硬件实现环境。对该技术与基于MPLS的IPv6 VPN隧道技术和NAT-PT技术的技术特点进行了详细比较。对研制的设备在试验网络中的参数配置和功能验证情况进行了说明。     

负折射率柱形光子晶体的全反射隧穿特性

为了研究一维含负折射率柱形光子晶体的全反射隧穿效应,利用特征矩阵法研究了光波在大于全反射角入射一维含负折射率柱形光子晶体时所产生的全反射隧穿教应。得出了基全反射隧穿峰的频率随周期数、模式量子数以及圆柱半径的变化特性。     

通信电缆管道和其他地下管线的交越

本文介绍了通信电缆管线与其他专业地下管线交越的一般原则和具体情况应对措施.     

Boron-doped silicon film as a recombination layer in the tunnel junction of a tandem solar cell

Boron-doped hydrogenated silicon films with different gaseous doping ratios (B2H6/SiH4) were deposited in a plasma-enhanced chemical vapor deposition (PECVD) system. The microstructure of the films was investigated by atomic force microscopy (AFM) and Raman scattering spectroscopy. The electrical properties of the films were characterized by their room temperature electrical conductivity (σ) and the activation energy (Ea). The results show that with an increasing gaseous doping ratio, the silicon films transfer from a microcrystalline to an amorphous phase, and corresponding changes in the electrical properties were observed. The thin boron-doped silicon layers were fabricated as recombination layers in tunnel junctions. The measurements of the Ⅰ-Ⅴ characteristics and the transparency spectra of the junctions indicate that the best gaseous doping ratio of the recombination layer is 0.04, and the film deposited under that condition is amorphous silicon with a small amount of crystallites embedded in it. The junction with such a recombination layer has a small resistance, a nearly ohmic contact, and a negligible optical absorption.     

PTN网络环网保护技术研究

从提出和分析PTN网络保护技术现状问题出发,总结PTN环网保护对运营商的重要意义。通过研究PTN环网保护技术的原理和实现机制,对不同技术方案、技术标准的优缺点进行分析总结,同时也提出了笔者自己的观点和看法,提出了环网保护技术配置方案建议,最后对环网保护技术及PTN网络未来发展趋势进行了展望。     

Finite-State Markov Wireless Channel Modeling for Railway Tunnel Environments

In recent years,high-speed railways(HSRs)have developed rapidly with a high transportation capacity and high comfort level.A tunnel is a complex high-speed rail terrain environment.It is very important to establish an accurate channel propagation model for a railway tunnel environment to improve the safety of HSR operation.In this paper,a method for finite-state Markov chain(FSMC)channel modeling with least squares fitting based on non-uniform interval division is proposed.First,a path loss model is obtained according to measured data.The communication distance between the transmitter and receiver in the tunnel is non-uniformly divided into several large non-overlapping intervals based on the path loss model.Then,the Lloyd-Max quantization method is used to determine the threshold of the signal-to-noise ratio(SNR)and the channel state quantization value and obtain the FSMC state transition probability matrix.Simulation experiments show that the proposed wireless channel model has a low mean square error(MSE)and can accurately predict the received signal power in a railway tunnel environment.