基于结构诱导人工表面等离激元的宽带低耦合电路北大核心CSCD

实现超宽带传输和超高集成度设计是微波和太赫兹电路发展的终极目标。针对以上目标,本文提出了结构诱导人工表面等离激元的概念。基于此设计并验证了具有超高局附性和超小传输常数的结构诱导人工表面等离激元电路结构,打破了传统人工表面等离激元电路对传输常数和衰减常数的限制。理论分析和数值验证表明,相较于经典人工表面等离激元,具备优异的场局附性和传输特性的结构诱导人工表面等离激元具有明显的弱色散和低耦合特性,在电路设计中可以有效减少宽带信号传输的色散失真,同时提高布线密度。     

浅议ARP Spoof攻击

介绍了ARP协议的基本用途及存在的安全问题，由此引起的ARPSpoof攻击，介绍了几种有效的防御措施。     

ARP欺骗实现交换式网络数据包嗅探的原理及其防范

分析了共享式网络与交换式网络数据包嗅探的差别,利用ARP欺骗实现交换式网络数据包嗅探的原理与方法,并提出了应对措施。     

A compact leaky‐wave antenna using a planar spoof surface plasmon polariton structure

This article presents and validates a leaky‐wave antenna by using the spoof surface plasmon polariton (SSPP) technique. By properly designing the proposed SSPP unit, the SSPP wave can be switched between the confinement and radiation modes. A large radiation efficiency can be achieved by properly designing the modulation depth, which ensures that a compact SSPP leaky‐wave array can be realized by using a small number of SSPP radiation units. To verify the design, a prototype which consists of a SSPP feeding network and a 4 by 4 SSPP radiation units has been fabricated by using a low cost FR‐4 substrate. A good agreement between simulated and measured results has been obtained. The proposed array antenna shows the promising capability of the SSPP technique for leaky‐wave antenna applications.     

Deep‐Subwavelength Holey Acoustic Second‐Order Topological Insulators

Higher‐order topological insulators (HOTIs) belong to a new class of materials with unusual topological phases. They have garnered considerable attention due to their capabilities in confining energy at the hinges and corners, which is entirely protected by the topology, and have thus become attractive structures for acoustic wave studies and control. However, for most practical applications at audible and low frequencies, compact and subwavelength implementations are desirable in addition to providing robust guiding of sound beyond a single‐frequency operation. Here, a holey HOTI capable of sustaining deeply confined corner states 50 times smaller than the wavelength is proposed. A remarkable resilience of these surface‐confined acoustic states against defects is experimentally observed, and topologically protected sound is demonstrated in three different frequency regimes. Concerning this matter, the findings will thus have the capability to push forward exciting applications for robust acoustic imaging way beyond the diffraction limit.     

Bandwidth‐controllable band‐stop filter using spoof surface plasmon polaritons

This article presents a bandwidth‐controllable band‐stop filter based on spoof surface plasmon polaritons (SSPPs) transmission line in the microwave frequency band. The approach of introducing rectangular slots into the corrugation strips offers a greater degree of flexibility in the SSPPs unit cell design. Meanwhile, the high‐order mode can be pulled to the low frequency segment of interest. The lower and upper edge of the stop band of this filter, therefore, can be controlled independently and conveniently. An equivalent circuit model of this unique unit cell is proposed for analyzing stop band formation and guiding the design of this SSSPs filter. Both numerical simulations and measured results demonstrate excellent stop band performance of the filter. The proposed filter may have potential applications in the SSPPs‐based communication system.     

局域网ARP欺骗攻击与防御

ARP协议存在着很多缺陷,攻击者正是利用这些漏洞实施ARP地址欺骗,对局域网的通信造成威胁。可通过Sniffer嗅探法、命令提示符法、或借助相关软件工具查找定位ARP地址欺骗攻击者。而对于如何防御的问题,则可采用对计算机系统安全加固,利用ARP杀毒软件、ARP攻击探测器等方法解决之。     

MAC-IP地址绑定的一种软件实现方法

通过深入研究ARP协议,以ARP欺骗方式实现了主机MAC和IP地址的绑定,并设计了一个可以跨越多个子网进行管理的MAC IP地址绑定软件解决方案。对解决方案的各组成部分的功能进行了介绍,提出了代理端和主控端的概念,并给出了具体的实现方法,并且从带宽和系统资源占用方面提出了优化方案,目前这种管理方案已经成功应用于工程实践中。