Printed Electrochemical Devices Using Conducting Polymers as Active Materials on Flexible Substrates

This paper reports some of our initial works in pursuit of a simple and low-cost method of fabricating all-organic electrochemical diodes, triodes, and transistors on flexible plastic or paper substrates. Conducting polymer poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), utilized as an active component, is deposited by spin-coating or printing techniques. The devices are directly fabricated from design without the need for masks, patterns, or dies. The output characteristics of both half-wave and full-wave rectifier circuits from two-terminal diodes show stable performances at frequencies below 5 Hz. In three-terminal tunable triodes, threshold voltage can be tuned in the range between 0.25 and 1.6 V. In four-terminal transistors, ambipolar operation function can be realized in one single device. I/sub ON//I/sub OFF/ current ratios of 10/sup 3/-10/sup 4/ have been achieved in the triode and transistor at operating voltages below 3 V. In addition, the device applications in electrochromic displays, logical circuits, as well as the switching speed of the circuits and device stability, are discussed.     

即时通讯软件的安全性分析

在互联网服务中,即时通讯已成为了最流行的服务模式之一,人们对即时通讯的依赖程度也与日俱增。但是, 频频出现的病毒和黑客攻击使广大用户深受其害,即时通讯的安全问题也日益严峻。为了从根本上解决问题,本文对即时通讯软件的架构和协议进行了深入分析,目的是找出漏洞根源,给开发者和使用者提供防止漏洞的依据。     

Algebraic decoding of (103, 52, 19) and (113, 57, 15) quadratic residue codes

In this paper, two algebraic decoders for the (103, 52, 19) and (113, 57, 15) quadratic residue codes, which have lengths greater than 100, are presented. The results have been verified by software simulation that programs in C++ language have been executed to check possible error patterns of both quadratic residue codes.     

Rearrangeable nonblocking SOI waveguide thermooptic 4/spl times/4 switch matrix with low insertion loss and fast response

A rearrangeable nonblocking 4/spl times/4 thermooptic silicon-on-insulator waveguide switch matrix at 1.55-/spl mu/m integrated spot size converters is designed and fabricated for the first time. The insertion losses and polarization-dependent losses of the four channels are less than 10 and 0.8 dB, respectively. The extinction ratios are larger than 20 dB. The response times are 4.6 /spl mu/s for rising edge and 1.9 /spl mu/s for falling edge.     

加权二次有理Bézier插值曲线

在本文中,给定一组有序空间数据点列及每个数据点的切矢向量,利用加权二次有理Bézier曲线对数据点作插值曲线,使该曲线具有C1连续性,并且权因子只是对相应顶点曲线附近产生影响,同调整两个相邻的权因子可以调整这两个相邻顶点之间的曲线和它的控制多边形.     

Piezoresistive Behavior Study on Finger‐Sensing Silicone Rubber/Graphite Nanosheet Nanocomposites

A novel finger‐sensing nanocomposite with remarkable and reversible piezoresistivity is successfully fabricated by dispersing homogeneously conductive graphite nanosheets (GNs) in a silicone rubber (SR) matrix. Because of the high aspect ratio of the graphite nanosheets, the nanocomposite displays a very low percolation threshold. The SR/GN nanocomposite with a volume fraction of conductive nanosheets closest to that for the percolation threshold presents a sharp positive‐pressure coefficient effect of the resistivity under very low pressure, namely, in the finger‐pressure range (0.3–0.7 MPa), whereby the abrupt transition could be attributed to compressive‐stress‐induced deformation of the conducting network. The super‐sensitive piezoresistive behavior of the nanocomposite is accounted for by an extension of the tunneling conduction theory which provides a good approximation to the piezoresistive effect.     

电容传感器在使用中存在的几个问题及处理方法

随着电容测量技术的迅速发展，电容传感器在非电量测量和自动检测中得到广泛应用，但它在使用过程中也存在一些问题，针对在使用电容传感器过程中存在的几个问题，从电容传感器的原理和工作过程两个方面进行了讨论，并提出行之有效的处理方法。     

On effective offloading services for resource-constrained mobile devices running heavier mobile internet applications

Rapid advances in wireless mobile network technologies and mobile handsets (MHs) facilitate ubiquitous infrastructure that can support a range of mobile services and applications in addition to conventional mobile Internet access. One recent trend is to effectively run desktop PC-oriented heavier applications on MHs. However, due to their miniature, portable size, MHs are resource-constrained and therefore, running these applications directly on an MH is not satisfactory given a user's expectations. To cope with this problem, this article proposes a novel offloading service that can seamlessly offload some of the tasks of a mobile application from an MH to nearby, resource-rich PCs (called surrogates). The system architecture and key components of the proposed offloading service are presented, prototyped, and evaluated. The results of experiments and simulations have demonstrated the effectiveness and efficiency of this offloading service for mobile applications.     

Mathematical modelling of the oxidation of nickel titanium alloys

A one-dimensional bulk reaction model for the oxidation of nickeltitanium is formulated, with preferential oxidation of titaniumbeing included. The modelling is directed at the better understandingof the dominant mechanisms involved in the oxidation processand their significance for the biocompatibility of the alloy.Two different regimes for the relative diffusivities of oxygenand the metals are investigated. By assuming fast bulk reactions,different asymptotic structures emerge in different parameterregimes and the resulting models take the form of moving boundaryproblems. Different profiles of nickel concentration are obtained:in particular a nickel-rich layer (observed in practice) ispresent below the oxide/metal interface for the case when oxygenand the metals diffuse at comparable rates.     

Crystallographic report: catena‐Aqua(2,2′‐bipyrimidine)lithium(I) perchlorate

A lithium(I) coordination polymer has been formed from LiClO₄ and the 2,2′‐bipyrimidine (bpym) ligand in which each square pyramidal lithium(I) atom is coordinated in the basal plane by four nitrogen donor atoms derived from two bpym ligands and one water molecule at the apical position. These are connected into a layer structure via hydrogen‐bonding interactions involving the perchlorate anions. Copyright © 2004 John Wiley & Sons, Ltd.