拓扑激光器研究进展（特邀）

随着拓扑光子学的发展,对缺陷、微扰等具有鲁棒性的拓扑边缘态、拓扑角态的发现革新了半导体激光器,并且推动了拓扑激光器的发展。首先,回顾了近几年拓扑激光器的发展历程,以及不同拓扑激光器的原理;其次,分析了各类拓扑激光器的最新实现,并且解释了拓扑边缘态、拓扑角态的基础物理。在这些实验中,拓扑激光器的模式是由介质结构决定,并通过光学增益来激发激光。分析表明拓扑角态相比于拓扑边缘态具有强局域性、小模式体积,因此基于拓扑角态的拓扑激光器更高效,阈值更低,这为未来的光子集成芯片提供了可能;最后,展望了拓扑激光器面临挑战和潜在的应用方向,有助于探索更实用的拓扑激光器。     

光纤光栅最佳切趾函数的研究

采用耦合模理论，给出了用传输矩阵法计算光纤Bragg光栅（FBG）特性的方法，进而得到了在不同切趾函数形式下的FBG反射谱的数值解。通过理论分析，给出了最佳切趾函数反射谱和群时延特性曲线。     

Performance Analysis of UWB Channels for Wireless Personal Area Networks

Ultra-wide band (UWB) communication is one of the most promising technology for high data rate networks over short-range communication. The ultra-wide bandwidth offers pulses with very short duration that provides frequency diversity and multipath resolution. Ultra-wide band (UWB) channels raise new effects in the receiver, the amplitude fading statistics being different compared to the conventional narrow band wireless channels. This review paper focuses on modeling of ultra-wide band channels, especially for simulation of personal area networks and also discusses the benefits, application potential and technical challenges in wideband communication. The concept of Orthogonal Frequency Division Multiplexing (OFDM) has recently been applied in wireless communication systems due to its high data rate transmission capability with high bandwidth efficiency and its robustness to multi-path delay. UWB OFDM communication was proposed for physical layer in the IEEE 802.15.3a standard which covers wideband communication in wireless personal area networks. Since the channel model for multicarrier UWB communication is different from that of plain ultra-wide band channel, a novel modification method in UWB channel model is proposed with specific center frequency and multipath resolution. Moreover, dynamic channel estimation is necessary before demodulation of UWB OFDM signals since the radio channel is time varying and frequency selective for wideband systems. The performance of the proposed method is statistically analyzed using LS and MMSE based channel estimation methods.     

IPTV中组播技术的解决方案

文中介绍了IPTV业务的概念,分析了实现IPTV业务的播技术,并讨论了将组播隧道技术和应用层组播技术应用到IPTV中的解决方案.     

A cascade energy band structure enhances the carrier energy in organic vertical-type triodes

Organic vertical-type triodes (OVTs) based on the cascade energy band structure as emitter layer are studied. The electric characteristics were dramatically enhanced while incorporating the cascade energy under current driving and voltage driving modes. The improvement is attributed to that injection carriers can obtain higher energy through a stepwise energy level. When the device has a layered structure of F₁₆CuPC (10 nm)/PTCDI (10 nm)/pentacene (100 nm) in emitter, it exhibits a common-base transport factor of 0.99 and a common-emitter current gain of 225 under current driving mode and exhibits a high current modulation-exceeding ?520 μA for a low collector voltage of ?5 V and a base voltage of ?5 V and the current on/off ratio of 10³ under voltage driving mode. Furthermore, we realized first organic current mirror that exhibited out/in current ratio of 0.75 and output resistance of 10⁵ Ω by using the OVTs.     

Microstructure Functional Devices—Effectively Manipulate Terahertz Waves

Terahertz （THz） technology promises important applications including imaging, spectroscopy, and communications. However, one of limitations at present for advancing THz applications is the lack of efficient devices to manipulate THz waves. Here, our recent important progresses in THz functional devices based on artificial microstructures, such as photonic crystal, metamaterial, and plasmonic structures, have been reviewed in this paper, involving the THz modulator, isolator, and sensor. These THz microstructure functional devices exhibit great promising potential in THz application systems.     

基于IETM的地震台网设备维修保障系统研究

由于地震台网设备种类多,台网站点分布散,需要一种有效的维修资源整合手段.为了整合维修信息资源,将交互式电子技术手册IETM技术引入台网设备的维修保障,研究并设计了一种基于IETM技术的地震台网设备维修保障系统.系统采用浏览器/服务器(B/S)模式三层结构模型,各台网浏览器通过网络与维修保障中心连接,基于ASP.NET模式设计了系统主要功能,实现了故障维修、系统管理等功能服务以及设备信息、技术状态信息等数据服务的共享.试用结果表明,该系统可有效提高台网设备维修效率.     

Bandwidth Improvement of Stub Loaded Compact Ultra-Wideband Microstrip Patch Antenna for C/X-Band Applications

Wireless Personal Communications - Authentication is a term very important for data communication security. We see many frauds due to authentication failure. The problem manifolds when...     

网络虚拟化互通技术

工业界和学术界提出了许多新的网络虚拟化技术来满足云计算环境对网络服务的需求.网络虚拟化技术的多样化使得云环境面临多种网络虚拟化技术共存的状况.然而,网络虚拟化技术间的差异会导致网络资源被分割成相互间不可通信的“孤岛”.为了解决这个问题,提出了网络虚拟化互通技术,分析了该技术的实现难点,并提出了基于软件定义网络的网络虚拟化互通架构Omni-Bridge,最后给出了Omni-Bridge的原型实现和功能验证.     

基于口令识别的无线控制系统的设计

文章将口令识别与无线通信、机器人控制相结合,实现了基于口令识别的智能车无线控制系统。该系统包含接收和识别口令的主机,发送指令和接收指令的通信模块以及带有特定功能的智能车。主机识别口令后,以无线传送方式将指令发送给智能车,智能车按指令实现相应功能。主机和智能车都基于嵌入式系统。主机硬件电路由三星S3C6410处理器和外围电路组成,口令识别部分采用连续隐马尔科夫模型算法。实验表明,该系统有良好的稳定性和实用性。