用3D-FDTD法分析用于近场光存储的光纤探针电磁波传输特性

提高近场光存储的存储信息密度的关键主要在于掌握近场存储光纤探针的透光率、近场光斑直径尺寸以及场梯度等近场物理量。采用三维时域有限差分 (3D FDTD)法分析了可用于近场光存储的光纤探针尖的光学性质 ,对不同类型光纤的近场光场分布进行了数值计算 ,给出结果并进行比较 ,从光学性质的角度对其在近场光存储中的应用加以讨论。完全镀膜光纤尖在极近场处的光斑可获得 10nm的尺寸 ,远小于传统光纤光学聚焦的光斑尺寸大小。     

彩电系统中静音电路的原理与设计

结合市场销量较大的熊猫TMPA88xx系列彩电电路,简要介绍静音电路的功能用途,阐述几款常用伴音功放电路的静音原理,讨论并提供相关软件的支持和硬件电路的设计.     

苏州台通过合理配置打造高效媒资系统

目前媒资资产管理系统在电视台的节目生产流程中已经占据了非常重要的地位的问题.为了能使媒资系统更好地为节目生产服务,苏州台通过对各问题节点具体分析,进行配置优化而非追加投资,保证了在投入有限的情况下,成功建设了高效率的媒资系统.实践证明,这次改造取得了很好的效果.     

Tuning the Charge Transfer Dynamics of the Nanostructured GaN Photoelectrodes for Efficient Photoelectrochemical Detection in the Ultraviolet Band

The intriguing surface sensitivity of the single-crystalline semiconductor nanowires offers tremendous opportunity in tuning the physical properties of nanophotonic and nanoelectronic devices for versatile applications. Particularly, in the pursuit of emerging photoelectrochemical (PEC)-type devices, significant efforts have been devoted to understanding the charge transfer dynamics between the nanowires and the electrolyte. Here, a PEC-type ultraviolet photodetector consisting of GaN p-n junction nanowires as photoelectrodes is constructed. It is found that two competing charge transport processes at the nanowires’ surface as well as in the p-n junction co-determine the photoresponsive behavior of the device. Furthermore, the surface platinum (Pt) decoration has successfully tuned the charge transfer dynamics by enhancing the charge transport efficiency at the surface, resulting in a twenty-fold increase of the photocurrent compared to the pristine GaN nanowires. Theoretical calculations reveal that the newly formed electronic states at the Pt/GaN interface account for the improved charge transfer at the surface, and the optimal hydrogen adsorption energy contributes to the boosted PEC reaction rate. The synergy of these two effects uncover the underlying mechanism of the high photoresponse of the constructed Pt/GaN-nanowires-based PEC photodetectors.     

L 波段宽带缝隙耦合天线设计

本文采用变异hour glass 形状缝隙耦合馈电,并引入背腔结构,设计了一种适用于L 波段,具有良好波束前后 比特性的宽带缝隙耦合微带天线,并讨论了馈电网络参数和背腔结构对天线性能的影响。设计结果表明：该天线驻波 相对带宽≥50%,频带内辐射前后比均≥12dB。     

An efficient and provably‐secure certificateless signature scheme without bilinear pairings

Certificateless public key cryptography simplifies the complex certificate management in the traditional public key cryptography and resolves the key escrow problem in identitybased cryptography. The certificateless signature scheme is studied widely as an important primitive. Following the pioneering work done by Al‐Riyami et al., many certificateless signature schemes using bilinear pairings have been proposed ever since. However, the relative computation cost of the pairing is approximately 20 times higher than that of the scalar multiplication over the elliptic curve group. To improve the performance we propose a certificateless signature scheme without bilinear pairings. With the running time being reduced greatly, our scheme is more practical than the previous related schemes for practical application. Copyright © 2011 John Wiley & Sons, Ltd.     

Microstructure and mechanical properties of Sn–Zn–Bi–Cr lead-free solder

In this paper, the effect of trace addition of Cr on the mechanical properties and reliability on Sn–8Zn–3Bi solder alloys was investigated. It has been demonstrated that the microstructure of solder alloys was refined after doping traces of Cr. The elongation reaches up to 40.63% after doping 0.1% Cr; and the fracture mechanism converts from quasi-cleavage fracture into ductile fracture. With aging time of 0, 4, 9 and 16 days, mechanical property of Sn–8Zn–3Bi–0.3Cr alloy was improved slightly. It was found that the Sn–Zn–Cr phase was increased and Zn in alloy was consumed after aging, so that the amount of primary Zn phase was reduced and microstructure was improved.     

钽粉氧含量对其钽阳极漏电流的影响

在多年实践经验基础上，用氧含量Ｘ１（质量分数）０．２０％～０．３８％的四种钽粉，控制钽阳极中残余氧含量Ｘ２（质量分数）在０．０８％～０．２０％间，采用正交设计实验研究了对其漏电流的影响，并建立了漏电流峰值ＩＬ和Ｘ１、Ｘ２间的预示方程，描述了漏电流和钽粉氧含量（Ｘ１）、残余氧含量（Ｘ２）间的关系。随后，用预示方程讨论了钽中氧和钽阳极中残余氧对其漏电流的影响。     

无线局域网

本文介绍了无线局域网的概念、结构、技术优势、ＣＳＭＡ／ＣＡ协议和标准化工作，并简介了目前主要产品以及作者一些建议。