三层交换机的工作原理

目的 研究三层交换机的工作原理及性能。方法 以ＢＡＹ公司的Ｓｗｉｔｃｈ Ｎｏｄｅ为全估层交换机的自学习方式和路由选择方法，结果 三层交换机路由选择所花延迟时间比一般路由器少得多。结论 三层交换机能代替路由哭喊 实现子网与ＶＬＡＮ的连接功能。同时保持交换机低延迟、低价位、大容量的特性、能改善网络服务速度。     

三层交换机实现VLAN间的路由

在很多校园网中,为了保证网络安全,在各部门间都设置了VLAN,为了实现部门间数据共享和通信安全,通常利用三层交换机实现校园网中各部门相互访问,文章用实例说明如何实现校园网中VLAN的互相通信。     

VLAN规划和配置在数字化校园网建设中的应用

随着网络规模的扩大,网络上大量的广播信息导致网络传输效率低下,为解决这个问题,产生了虚拟局域网技术(VLAN)。介绍解决网络二层广播报文泛滥的VLAN技术,以华为交换机为基础,设计并实现一个VLAN功能应用代表性的网络互连方案。     

鹤岗矿区通讯专用网宽带接入技术论述

本文就鹤矿集团水电热力公司矿区通讯电话专用网宽带接入技术的特点和应用情况作以论述，简述通讯电话专用网宽带接入方式和传输过程，以及VLAN组网技术在宽带网络中的重要作用。论述通讯专用网接人宽带网络是合理的，实用的，而事实证明该组网方案也是确实可行的。     

小型局域网的规划设计及管理

本文以一位网络管理员的角度详细论述了局域网的规划设计及管理，在论述中着重阐述了如何快速的通信如何方便的管理。并且通过一个酒店的实际例子，详细介绍了小型局域网是如何规划设计的，且着重介绍了用到的技术。     

浅析VLAN技术在企业局域网中的应用

介绍了VLAN技术相比传统局域网组网方式,VLAN技术在企业局域网中的优势以及实现方式。并且通过实例浅析了VLAN技术在企业局域网中的应用。     

浅析计算机网络拓扑与网络设备

计算机网络的发展超过了任何一种科学技术的发展速度,计算机网络的应用已经涉及到各个行业,同我们的工作和生活密切相关.重点介绍计算机局域网络拓扑结构的发展,以及网络交换机和路由器的特点、功能和应用.     

路由器集群技术

随着互联网的不断普及,以及新兴技术的交替出现,作为网络核心的路由器设备,也面临着新的挑战。分析目前核心路由器的发展趋势,并对目前流行的集群技术作了详细的分析。近年来,路由器的发展有起有伏。20世纪90年代中期,传统路由器成为制约因特网发展的瓶颈,被ATM交换机取而代之,成为IP骨干网的核心,路由器变成了配角。     

VLAN技术在县级供电公司网络中的应用

目前,VLAN技术已广泛用于各种企业网络中,尤其是逐渐成为应用焦点的以太网技术更值得深入分析。通过对VLAN定义及其优势的阐述,通过对VLAN技术标准的运用,对VLAN的划分形式、具体设计,以及配置管理进行分析,并在此基础上构建基于Cisco4507交换机的VLAN体系,实践证实其可较大提高网络的安全性和性能。     

设置交换机及路由器，使网络更加安全可靠

介绍了交换机及路由器安全设置。     

一种实现QoS控制的输入缓存交换机调度算法

提出了一种新的ATM交换机调度算法：加权公平迭代匹配（WFIM）。WFIM采用输入缓存的交换机，具有实现简单的优点，其在输入流是独立同分布的Bernoulli过程且目的的地址均匀分布在输出端口时，可以提供与iSLIP相似的平均时延，并达到100％的通量。VFIM最重要的优点是可以提供QoS的保证，即限制过度使用带宽的连接，以保证宫接的服务质量。WFIM的复杂度是O（N^2*lo2(N），可以分布在多个CPU上同时进行。     

消费者后悔情绪对投诉、转换行为的影响研究

文章以杭州市四所大学的270名大学生为样本，以手机购买行为为问卷调查的情境，实证研究了在中国背景下消费者后悔情绪对购买后投诉、转换行为的影响以及关系质量（满意、信任、承诺）在此关系中的缓冲作用。结果显示，消费者后悔情绪与投诉、转换行为都显著正相关；信任与承诺是后悔与转换行为间关系的缓冲变量。从而说明，消费者对购买决策感到后悔就将采取投诉行为或转换品牌、商家，而若消费者对商家有着较高的信任或承诺，就将降低后悔引发的投诉、转换行为倾向。     

Switching enhancement and suppression of four-wave mixing via a dressing field

The switch between the enhancement and suppression of the four-wave mixing (FWM) process in an electromagnetically induced transparency (EIT) window via quantum interference has been demonstrated experimentally. The enhancement and suppression of the FWM signal, as well as the EIT window, switch with a change in the probe detuning. Also, by controlling the powers of the dressing and probe fields, the enhancement and suppression of the FWM signal can be switched and an optimized enhancement can be obtained. Such a switch of the enhancement and suppression of the FWM signal intensity can find potential applications in optical switches, optical communication and quantum information processes.     

TbW10-Agarose柔性自支持绿光薄膜的制备及化学响应荧光开关性能研究

基于功能互补原理, 以稀土多酸Na₉TbW₁₀O₃₆(TbW₁₀)为发光功能组分、琼脂糖为成膜基质, 通过溶胶-凝胶及Casting技术制备了稀土多酸柔性自支持绿光薄膜TbW₁₀-Agarose, 利用FT-IR、Raman光谱对薄膜的组成及结构进行表征, 利用SEM、AFM和TEM对薄膜的厚度、表面粗糙度和微结构进行研究, 考察TbW₁₀掺杂量对薄膜透光率及发光性能的影响。在HCl/NH₃刺激下, 实现了TbW₁₀-Agarose绿光薄膜可逆的化学响应荧光开关性质, 利用荧光动力学方法对绿光薄膜化学响应荧光开关的响应时间及可逆性进行研究; 并拓展了该绿光薄膜对HCl气体的荧光光谱检测, 检出限为0.2731 mmol·L ^-1。     

Dynamic Orthogonal Switching of a Thermoresponsive Self‐Organized Helical Superstructure

Controllable manipulation of self‐organized dynamic superstructures of functional molecular materials by external stimuli is an enabling enterprise. Herein, we have developed a thermally driven, self‐organized helical superstructure, i.e., thermoresponsive cholesteric liquid crystal (CLC), by integrating a judiciously chosen thermoresponsive chiral molecular switch into an achiral liquid crystalline medium. The CLC in lying state, in both planar and twisted nematic cells, exhibits reversible in‐plane orthogonal switching of its helical axis in response to the combined effect of temperature and electric field. Consequently, the direction of the cholesteric grating has been observed to undergo 90° switching in a single cell, enabling non‐mechanical beam steering along two orthogonal directions. The ability to reversibly switch the cholesteric gartings along perpendicular directions by appropriately adjusting temperature and electric field strength could facilitate their applications in 2D beam steering, spectrum scanning, optoelectronics and beyond.     

矩阵变换器的控制原理及仿真研究

详细介绍了矩阵变换器的拓扑结构及工作原理,并讨论了矩阵变换器的开关函数调制方法和空间矢量调制方法。最后对基于上述两种调制策略的矩阵变换器进行仿真。由结果可知:采用空间矢量调制时电机启动较快,低频和高频时电机的运行性能也好于开关函数调制,但采用开关函数调制时,电机的定子电流谐波特性好于空间矢量调制所得到的结果。     

Reaction Bonding of Three-Layer Alumina-Based Composites

Three-layer alumina-based composites with Al₂O₃-containing mullite as the outer layer and ZrO₂-containing alumina as the inner layer were fabricated by die-pressing and reaction bonding. The effects of the outer-layer compositions on the densification behavior of three-layer composites were investigated. The existence of residual stresses in the layers was verified using indentation methods. Compared with single-layer ceramics, three-layer composites exhibit an improved fracture toughness and an excellent damage resistance due to the presence of the compressive stresses in the outer layers.     

Heat Conduction Analysis of Nonhomogeneous Functionally Graded Three-Layer Media

Functionally graded material (FGM) is a particulate composite with continuously changing its thermal and mechanical properties in order to raise the bonding strength in the discrete composite made from different phases of material constituents. Furthermore, FGM is a potent tool to create an intermediate layer in metal–ceramic composites to avoid the properties discontinuities and reduce, thereby, the residual stresses. For the nonhomogeneous problem, the mathematical derivation is much complicated than the homogeneous case since the material properties vary with coordinate. To analyze the problem, the Fourier transform is applied and the general solution in transform domain is obtained. The inverse Fourier transform is performed to get the results in physical domain for temperature and heat fluxes. Numerical results for the full-field distributions of temperature and heat fluxes with different functionally graded parameters are presented. The continuous characteristics of the temperature and heat flux along the interface are emphasized and some interesting phenomena are presented in this study. The results show that all the fields (temperature and heat fluxes) are continuous at the interface if the conductivities are continuous at the interface. Moreover, the first derivatives of temperature and heat flux qy are continuous at the interface.