平面空间聚焦器的研究

本文采用几何光学的方法设计了将平面平行光聚焦为圆的平面空间聚焦器 ,绘制出了平面空间聚焦器的图样 ,并进行了成像模拟 ,结果表明 ,聚焦器能够得到指定的圆。     

基于CMA算法的自适应阵的初始化研究

在多径传播和其它同频干扰存在而同时接收到多个恒模信号时,若已知需要信号到达方向的通信条件下,本文提出了恒模算法的初始预测方法,对干扰起到了零陷作用,数字模拟结果表明了这一初始预测方法是有效的。     

ISP技术在数字系统课程设计的应用

介绍了ＩＳＰ技术的发展,以及如何利用这种技术进行数字系统课程设计。实践证明,这种做法既能使学生的理论知识得到综合和提高,又能锻炼学生的技能并开拓其创造力。     

All‐Carbon Nanotube‐Based Flexible Field‐Emission Devices: From Cathode to Anode

The fabrication of a flexible field‐emission device (FED) using single‐walled carbon nanotube (SWNT) network films as the conducting electrodes (anode and cathode) and thin multi‐walled CNT/TEOS hybrid films as the emitters is reported. P‐type doping with gold ions and passivation with tetraethylorthosilicate (TEOS) made the SWNT network film highly conductive and environmentally stable, and hence a good alternative to conventional indium tin oxide electrodes. CNT/TEOS hybrid emitters showed high current density, low turn‐on field, and long‐term emission stability, compared with CNT emitters; these characteristics can be attributed to the TEOS sol, acting both as a protective layer surrounding the nanotube tip, and as an adhesive layer enhancing the nanotube adhesion to the substrate. All‐CNT‐based flexible FEDs fabricated by this approach showed high flexibility in field emission characteristics and extremely bright electron emission patterns.     

Strain Anisotropies and Self‐Limiting Capacities in Single‐Crystalline 3D Silicon Microstructures: Models for High Energy Density Lithium‐Ion Battery Anodes

This study examines the crystallographic anisotropy of strain evolution in model, single‐crystalline silicon anode microstructures on electrochemical intercalation of lithium atoms. The 3D hierarchically patterned single‐ crystalline silicon microstructures used as model anodes were prepared using combined methods of photolithography and anisotropic dry and wet chemical etching. Silicon anodes, which possesses theoretically ten times the energy density by weight compared to conventional carbon anodes, reveal highly anisotropic but more importantly, variably recoverable crystallographic strains during cycling. Model strain‐limiting silicon anode architectures that mitigate these impacts are highlighted. By selecting a specific design for the silicon anode microstructure, and exploiting the crystallographic anisotropy of strain evolution upon lithium intercalation to control the direction of volumetric expansion, the volume available for expansion and thus the charging capacity of these structures can be broadly varied. We highlight exemplary design rules for this self‐strain‐limited charging in which an anode can be variably optimized between capacity and stability. Strain‐limited capacities ranging from 677 mAhg^?1 to 2833 mAhg^?1 were achieved by constraining the area available for volumetric expansion via the design rules of the microstructures.     

Enhanced DNA Sequencing Performance Through Edge‐Hydrogenation of Graphene Electrodes

The use of graphene electrodes with hydrogenated edges for solid‐state nanopore‐based DNA sequencing is proposed, and molecular dynamics simulations in conjunction with electronic transport calculations are performed to explore the potential merits of this idea. The results of the investigation show that, compared to the unhydrogenated system, edge‐hydrogenated graphene electrodes facilitate the temporary formation of H‐bonds with suitable atomic sites in the translocating DNA molecule. As a consequence, the average conductivity is drastically raised by about 3 orders of magnitude while exhibiting significantly reduced statistical variance. Furthermore, the effect of the distance between opposing electrodes is investigated and two regimes identified: for narrow electrode separation, the mere hindrance due to the presence of protruding hydrogen atoms in the nanopore is deemed more important, while for wider electrode separation, the formation of H‐bonds becomes the dominant effect. Based on these findings, it is concluded that hydrogenation of graphene electrode edges represents a promising approach to reduce the translocation speed of DNA through the nanopore and substantially improve the accuracy of the measurement process for whole‐genome sequencing.     

基于Simulink的信道编码模块封装与仿真

利用Matlab软件的Simulink软件包提供的功能，封蓑了通信系统中常见的信道编码模块，并做了基于这些模块的通信系统仿真．本文所做的工作可为基于Simulink的通信系统仿真提供参考与支持。     

关联规则挖掘结果的可视化技术研究

数据挖掘结果可视化是将数据挖掘后得到的知识和结果以图形等可视化形式表示出来,从而使用户可以更加方便并深入地对结果进行观察和分析.本文介绍了关联规则的基本概念,详细讨论了用于关联规则挖掘结果可视化的几种常用技术,并对其进行分析比较,给出了各自的优缺点.     

宽带接入网网管中的SNMP管理接口技术

随着宽带接入网在我国的广泛应用,宽带接入网的网管系统建设也越来越重要了.分析宽带接入网网络管理中的关键技术,及采用TMN体系结构和SNMP网络管理接口技术的优势,介绍SNMP原理和SNMP网络管理接口的实现过程.     

通道增益的有源估计方法

在DOA估计中解决通道不一致性问题的关键是设法求得各通道的复增益。本文利用在天线阵列所在平面设置的一个校正源，运用信号空间对信号DOA和通道增益的约束关系对通道增益进行估计，在未知校正信号DOA时可通过迭代的方法获得二者的一致估计。仿真证明了此方法的有效性。