A Parallel Platform for Web Text Mining

With user-generated content, anyone can De a content creator. This phenomenon has infinitely increased the amount of information circulated online, and it is beeoming harder to efficiently obtain required information. In this paper, we describe how natural language processing and text mining can be parallelized using Hadoop and Message Passing Interface. We propose a parallel web text mining platform that processes massive amounts data quickly and efficiently. Our web knowledge service platform is designed to collect information about the IT and telecommunications industries from the web and process this in-formation using natural language processing and data-mining techniques.     

基于多基地雷达的高超声速目标跟踪研究

对多基地雷达跟踪高超声速目标进行了研究,针对高超声速目标高速高机动的特点,提出了使用参考加速度模型的IMM算法。同时在对多基地雷达造成的非线性问题中采用了UKF滤波。通过蒙特卡罗仿真对比,该算法跟踪效果较好,误差均方值小,跟踪精度高。     

模拟电路优化设计理论与关键技术研究

模拟电路在作业过程中中会出现多种故障,解决这些故障并对模拟电路进行优化,是开展模拟电路后续工作的基础.文章在解决故障的基础上对模拟电路进行优化设计,从物理综合和结构级综合两个方面介绍了模拟集成电路优化综合流程;从基础优化、版图优化、知识优化等方面分析了模拟集成电路优化设计关键技术,旨在为模拟电路优化以及日常故障诊断等提...     

Superior Micro‐Supercapacitors Based on Graphene Quantum Dots

Graphene quantum dots (GQDs) have attracted tremendous research interest due to the unique properties associated with both graphene and quantum dots. Here, a new application of GQDs as ideal electrode materials for supercapacitors is reported. To this end, a GQDs//GQDs symmetric micro‐supercapacitor is prepared using a simple electro‐deposition approach, and its electrochemical properties in aqueous electrolyte and ionic liquid electrolyte are systematically investigated. The results show that the as‐made GQDs micro‐supercapacitor has superior rate capability up to 1000 V s^?1, excellent power response with very short relaxation time constant (τ₀ = 103.6 μs in aqueous electrolyte and τ₀ = 53.8 μs in ionic liquid electrolyte), and excellent cycle stability. Additionally, another GQDs//MnO₂ asymmetric supercapacitor is also built using MnO₂ nanoneedles as the positive electrode and GQDs as the negative electrode in aqueous electrolyte. Its specific capacitance and energy density are both two times higher than those of GQDs//GQDs symmetric micro‐supercapacitor in the same electrolyte. The results presented here may pave the way for a new promising application of GQDs in micropower suppliers and microenergy storage devices.     

高频电介质新材料Ba2Ti3Nb4O18陶瓷

采用氧化物固相反应法制备了理论密度达96.8%以上的Ba2Ti3Nb4O18高频电介质陶瓷。XRD和SEM分析表明:该陶瓷为两相混合结构,主晶相为单斜Ba2Ti3Nb4O18相,次晶相为六方Ba3Ti4Nb4O21相。1250℃/2h烧结瓷体Ba3Ti4Nb4O21相的体积分数为5%~8%,1MHz下的介电性能为:εr约为38,tanδ约为1.6×10–4,αC约为–8.51×10–6/℃。     

I^2C串行总线存储技术在单片机系统中的应用

介绍I^2C串行总线原理及AT24CXX系列串行EEPROM的特点。着重阐述了利用I^2C串行总线和AT24CXX系列串行EEPROM实现数据存储的技术，并给出了该技术在MCS51系列单片机系统中的实现方法。     

雷达系统生存能力的综合评估

生存能力是雷达系统的一个重要指标。针对雷达系统指标要求建立了生存能力的指标体系；采用结合了层次分析法的灰色综合评判法评估了系统的生存能力。通过示例验证了层次——灰色分析法的正确性和可行性，为雷达系统的方案论证、工程研制和鉴定定型等提供了决策依据。