光纤级联系统中准孤子传输的数值模拟

本文基于一种光纤级联系统模型,用数值模拟方法考察准孤子在这种中的传输情况,得到了传输１００００ｋｍ的最佳方案并给出了当输入光脉冲的峰值功率、初始宽及啁啾变化时,系统的传输特性     

化合物半导体的THz发射光谱

利用反射式太赫兹(THz)辐射产生与探测系统,研究了基于不同半导体的THz发射光谱.通过快速傅里叶变换,由测得的THz时域光谱得到了其相应的频域光谱,从而对不同半导体的THz发射性质进行了比较.结果表明,未掺杂的砷化铟(InAs)较其他半导体材料有更高效的THz发射效率.     

一种基于交换机的彩铃业务实现方案

首先介绍了在GSM移动网络中实现彩铃业务的原理，然后提出一种基于交换机实现彩铃业务的技术方案，分析了此方案中媒体设备的物理结构和内部信令的交互过程，最后将该方案与基于智能网的方案进行了对比。     

范德堡和条状结构埋层电阻的测试及研究

薄层电阻经常被用于PCM以及SPICE模型的关键电阻测试。在正常情况下呈现欧姆特性。同时我们可以看到,随偏压的变化,JFET器件中的埋层电阻也发生相应的变化。本文研究了条形电阻和范德堡两种标准结构的电阻,同时利用2D、3D器件模拟,给出了优化电阻测试的路径和方法。     

Gazing-detection of human eyes based on SVM

A method for gazing-detection of human eyes using Support Vector Machine （SVM） based on statistic leaming theory （SLT） is proposed. According to the criteria of structural risk minimization of SVM,the errors between sample-data and model-data are minimized and the upper bound of predicting error of the model is also reduced. As a result,the generalization ability of the model is much improved. The simulation results show that, when limited training samples are used, the correct recognition rate of the tested samples can be as high as 100% ,which is much better than some previous results obtained by other methods. The higher processing speed enables the system to distinguish gazing or not-gazing in real-time.     

主流电子交易网站账户安全登录模式缺陷与安全设计

账户的使用是互联网的基础应用之一。由于传统账户登录方式存在极大的安全隐患,不少大型电子交易网站如银行、淘宝等逐步采用了安全控件登录的方式。文章对安全登录、传输以及身份认证过程进行了分析,指出了其中存在的重放攻击漏洞,提出了采用时间戳的公钥登陆安全模型来解决漏洞的方法。     

Highly Oriented Nanofibrils of Regioregular Poly(3‐hexylthiophene) Formed via Block Copolymer Self‐Assembly in Liquid Crystals

A novel method making use of block copolymer self‐assembly in nematic liquid crystals (LCs) is described for preparing macroscopically oriented nanofibrils of π‐conjugated semiconducting polymers. Upon cooling, a diblock copolymer composed of regioregular poly(3‐hexylthiophene) (P3HT) and a liquid crystalline polymer (LCP) in a block‐selective LC solvent can self‐assemble into oriented nanofibrils exhibiting highly anisotropic absorption and polarized photoluminescence emission. An unusual feature of the nanofibrils is that P3HT chains are oriented along the fibrils' long axis. This general method makes it possible to use LCs as an anisotropic medium to grow oriented nanofibrils of many semiconducting polymers insoluble in LCs.     

带约束的复FIR数字滤波器Chebyshev设计算法

本文主要讨论了复FIR数字滤波器的频域不等式约束Chebyshev设计问题.作者首先把文献[1]中的复交错点组定理扩展到有不等式约束的情况,之后根据扩展定理中对最优解特性的描述,并结合复Remez算法[1]及赖晓平的迭代Remez算法[2][3],提出了一种有效的算法来解决频域带不等式约束的复FIR数字滤波器的Chebyshev设计问题.如果问题的解存在,则算法能保证收敛到最优解.作者用MATLAB语言对上述算法进行了实现并做了仿真分析.     

SG-DBR激光器波长控制系统的设计与实现

根据宽可调谐SG-DBR激光器的波长调谐特性,研制了一套波长控制系统。系统通过生成并调用“波长-电流”数据查询表,实现对SG-DBR激光器输出波长的调谐控制。系统设计引入了虚拟仪器和单片机技术,达到了降低设备成本、小型化系统的目的。实验证明系统波长控制精度高,波长控制误差不超过±0.02nm。     

Improved photovoltaic characteristics of organic cells with heterointerface layer as a hole-extraction layer inserted between ITO anode and donor layer

We have fabricated an improved organic photovoltaic (OPV) cell in which organic heterointerface layer is inserted between indium-tin-oxide (ITO) anode and copper-phthalocyanine (CuPc) donor layer in the conventional OPV cell of ITO/CuPc/fullerene (C₆₀)/bathophenanthroline (Bphen)/Al to enhance the power conversion efficiency (PCE) and fill factor (FF). The inserted ITO-buffer layer consists of electron-transporting layer (ETL) and hole-transporting layer (HTL). We have changed the ETL and HTL materials variously and also changed their layer thickness variously. It is confirmed that ETL materials with higher LUMO level than the work function of ITO give low PCE and FF. All the double layer buffers give higher PCE than a single layer buffer of TAPC. The highest PCE of 1.67% and FF of 0.57% are obtained from an ITO buffer consisted of 3 nm thick ETL of hexadecafkluoro-copper-phthalocyanine (F₁₆CuPc) and 3 nm thick HTL of 1,1-bis-(4-methyl-phenyl)-aminophenylcyclohexane (TAPC). This PCE is 1.64 times higher than PCE of the cell without ITO buffer and 2.98 times higher than PCE of the cell with single layer ITO buffer of TAPC. PCE is found to increase with increasing energy difference (ΔE) between the HOMO level of HTL and LUMO level of F₁₆CuPc in a range of ΔE < 0.6 eV. From the ΔE dependence of PCE, it is suggested that electrons moved from ITO to the LUMO level of the electron-transporting F₁₆CuPc are recombined, at the F₁₆CuPc/HTL-interface, with holes transported from CuPc to the HOMO level of HTL in the double layer ITO buffer ETL, leading to efficient extraction of holes photo-generated in CuPc donor layer.