Vesicle‐Assisted Assembly of Mesoporous Ce‐Doped Pd Nanospheres with a Hollow Chamber and Enhanced Catalytic Efficiency

Mesoporous Ce‐doped Pd nanospheres with a hollow chamber are synthesized by chemical reduction of PdCl₂ with KBH₄ in an aqueous solution containing Ce(NO₃)₃ and Bu₄PBr. The later acts as a template for the hollow chamber via forming organic vesicles. During the liquid‐phase phenol hydrogenation to cyclohexanone, the as‐prepared catalyst exhibits a much‐higher activity than the corresponding solid nanoparticle catalyst prepared in the absence of Bu₄PBr. Meanwhile, the Ce dopants greatly enhance the activity and selectivity to cyclohexanone. The hollow chamber is quite stable against heating in solution and the catalyst could be used repetitively many times. Such a catalyst shows a good potential in industrial applications.     

PLC在中低压配电网自动化RTU中的应用

本文介绍了以PLC为主体的中低压配电网自动化中RTU的硬件组成和PCL软件设计。     

一个流水线型三维DCT硬件核的设计

在优化3D-DCT算法的基础上,采用流水线型结构,系数转换、矩阵转置、数据装载和截位的通盘解决方式,构造一个流水线型的三维DCT硬件核,使运动图像的压解中DCT运算的CPU耗时下降十几倍,实现实时压缩。     

软交换网络中媒体网关控制器的研究与设计

300万像素对于专业摄影来说可能不值一提，但是对于家庭用户而言却已经十分完美了。下面三款数码相机是300万家庭中令人兴奋的新品，它们的价格都在3000元到4000元人民币之间，想想一年前3000万像素的相机要花多少钱？而在测试中它们的表现也的确让人觉得物有所值。     

Cluster-based distributed consensus

In this paper, we incorporate clustering techniques into distributed consensus algorithms for faster convergence and better energy efficiency. Together with a simple distributed clustering algorithm, we design cluster-based distributed consensus algorithms in forms of both fixed linear iteration and randomized gossip. The time complexity of the proposed algorithms is presented in terms of metrics of the original and induced graphs, through which the advantage of clustering is revealed. Our cluster-based algorithms are also shown to achieve an Ω(log n) gain in message complexity over the standard ones.     

基于网络空间复用与累积干扰的无线Ad Hoc网络性能优化

无线Ad hoc网络中,网络容量主要依赖于网络的空间复用度以及由于节点并发所造成的累积干扰。文章首先分析了网络的空间复用与干扰对于网络容量的影响,将网络容量映射为网络的空间复用以及网络中存在的干扰的相互作用的函数。并进一步基于安全载波监听的概念,提出了一种空间复用提升以及干扰避免的节点数据发送策略。该策略能够根据网络当中存在的干扰动态地调整节点的发送方式,在提高网络空间复用的同时控制网络当中存在的干扰,从而达到网络性能优化的目的。理论分析以及仿真实验都证实了我们的策略能够有效的提高无线Ad Hoc网络的吞吐量,优化网络性能。     

一种基于博弈论的无线mesh网络信道分配算法

无线mesh网络中的信道分配会极大地影响网络的性能。为了解决无线mesh网络中的信道分配问题,提出了一种基于博弈论的信道分配(GBCA)算法。该算法将网络中每一个节点模型化为一个博弈者,每个博弈者的策略为信道的分配方案,并将整个网络的吞吐量作为效用函数的目标,效用函数的物理意义则是在给定流量需求矩阵下传输的成功率。博弈者通过相互博弈来优化收益函数,以最大化网络吞吐量。并针对GBCA算法的不足,提出了一种改进算法———GBCA-TP算法。通过NS2.34仿真分析得出,GBCA算法和GBCA-TP算法在收敛性、分组丢失率和吞吐量上都要优于当前的算法。     

TD-SCDMA和WCDMA系统基站的共容分析

主要探讨了WCDMA系统与TD-SCDMA系统基站间的共存问题,并从邻频干扰的角度进行了深入的分析,采用确定性计算方法和静态仿真方法研究TD—SCDMA基站对WCDMA基站产生的邻频干扰,并提出相应的解决方法。     

基于DSP技术的RFID读写器设计

文中介绍了RFID系统及RFID读写器,论述了基于DSP技术的RFID读写器设计方法.在描述RFID系统组成的基础上,给出了读写器的软硬件设计流程.重点阐述了RFID读写器的防冲突设计.该读写器已应用于门禁系统中,实际应用结果表明其性能良好.     

Low-index-material-based nano-slot waveguide with quasi-Bragg-reflector buffer

To confine guided light tightly in a small size with acceptable loss, recently a nanometre-size slot waveguide has been demonstrated experimentally [1]. Such a slot waveguide has two high-index regions (e.g. Si), between which there is a narrow slot region. This narrow slot usually has a width of about 100 nm (or less) and is filled by a low-index-material (e.g. air or SiO/sub 2/) [1]. Because of the continuity of the normal displacement field (product of the permittivity and electric field) at the interface between the low-index slot and the high-index region, one obtains an enhanced electric field intensity in the lowindex slot. This effect makes this novel type of optical waveguide very attractive in many applications [2, 3], e.g. modulation, nonlinear effects, sensing etc. In addition, some extended structures, e.g. a horizontal slot waveguide [4], a multiple-slot waveguide [5], etc. have also been developed.