基于Matlab的虚拟信号发生器设计

Matlab是一个数据分析和处理功能十分强大的工程实用软件。为输出提供了十分方便的函数和命令并且Matlab简单直观的图形用户接口易于掌握和使用。本文介绍了一种使用GUI工具箱。用Matlab实现应报信号发生器的设计。文章设计的信号发生器可以加深对信号处理概念的理解,具有一定的借鉴应用价值。     

c#．net调用matlab进行混合编程

本文结合一个小实例提出了几种混合编程的方法。     

浅谈传输通信网主流技术及其应用

目前,通信业处于急剧变革的时代,业务的发展导致电信网产生巨大的变革,未来的业务发展也对传输网络的技术提出了新的要求.本文主要分析阐释了"多业务传送平台(MSTP)、自动交换光网络(ASON)、城域波分(DWDM)、光传送网OTN、末端接入技术"等五种主流技术及它们的应用.     

FCMAC网络的软硬件协同设计与实现

提出了FCMAC网络的一种基于NiosII的软硬件协同设计方法,解决了FCMAC软件实现速度慢、硬件实现耗资源的不足。通过Matlab仿真得出FCMAC网络的各参数。分析影响软件实现FCMAC速度的关键算法,对FCMAC算法进行软硬件划分。在NiosII IDE开发环境下,基于C实现软件模块,以用户自定义指令形式实现硬件模块和软硬件的衔接,即完成软硬件的协同设计。试验结果表明,FCMAC的软硬件协同实现在软件实现速度慢、硬件实现耗资源之间实现了折中,可通过不同的软硬件划分,实现速度与资源的互换。     

Network traffic classification based on ensemble learning and co-training

Classification of network traffic is the essential step for many network researches. However,with the rapid evolution of Internet applications the effectiveness of the port-based or payload-based identifi-cation approaches has been greatly diminished in recent years. And many researchers begin to turn their attentions to an alternative machine learning based method. This paper presents a novel machine learning-based classification model,which combines ensemble learning paradigm with co-training tech-niques. Compared to previous approaches,most of which only employed single classifier,multiple clas-sifiers and semi-supervised learning are applied in our method and it mainly helps to overcome three shortcomings:limited flow accuracy rate,weak adaptability and huge demand of labeled training set. In this paper,statistical characteristics of IP flows are extracted from the packet level traces to establish the feature set,then the classification model is created and tested and the empirical results prove its feasibility and effectiveness.     

NKChemSQL——针对MySQL的化学信息学扩展

化学数据库是进行化学信息学研究的重要资源,分子属性与指纹计算、分子结构格式转换、分子相似度匹配、精确匹配和子结构匹配以及分子结构图片导出等,都是必需的基本服务内容。应用广泛的数据库系统MySQL却缺乏这些功能,难以满足化学信息处理、网站开发等开发的需求。NKChemSQL是自行编制的MySQL扩展库,通过对开源软件OpenBabel的功能进行包装,以SQL语言的格式完成相应操作。NKChemSQL具有良好的运行表现,经过对含26万余条分子结构信息的NCI数据库进行的测试,全结构匹配只需不到1秒而子结构匹配达300个结构/秒,相似度匹配则达1万个结构/秒。NKChemSQL为开发化学信息学软件和网站提供了非常便利的新方式。     

抗缺氧中藏药微量元素的对应分析

应用对应分析研究抗缺氧中藏药中微量元素Co、Cr、Cu、Fe、Mg、Mn、Ni and Zn的分布特征。该方法可用于直接处理抗缺氧中藏药样品元素分析的数据,以研究地奥心血康、红景天胶囊、安神散、五味石榴散、章松八味沉香散、十六味杜鹃散、二十五味余甘子丸、二十五味竹黄胶囊、十五味龙胆丸、秘诀清凉散、七十味珍珠丸、八味沉香散、六味丁香散、七味葡萄散等中藏药的品质与它们的微量元素组成和样品来源的关系。将样品点和微量元素变量反映到同一因子轴的图形上,并且分类,能够揭露出样品来源与变量之间的内在联系,中藏药中人体必需的微量元素Fe、Mg、Co、Cu、Mn和Ni等含量比较高,与药物疗效密切相关,为研制新型的具有微量元素优势的药物提供科学的依据。     

基于PC的便携式飞行模拟器三维引擎开发研究

随着模拟器体系的不断发展,模拟训练以其经济、安全、高效的特点日益在各个领域得到广泛应用。用DirectX进行三维引擎开发与研究已是当前的主流,其核心技术是DirectX图形的渲染。现以基于PC的便携式飞行模拟器三维引擎为研究对象,用C＋＋,Windows和DirectX的相关知识编程进行开发与研究。针对地景三维引擎的开发用纹理融合算法来实现。     

Effect of the fluctuation range of formation temperature on the preparation and superconductivity of Bi(Pb)2223 single-phase

Effects of the fluctuation range of formation temperature on preparation and superconducting properties of the Bi(Pb)2223 phase have been investigated in detail. Our results show that knowledge about the temperature distribution and fluctuation in the muffle furnace is necessary for preparation of the Bi(Pb)2223 single-phase. Single-phase samples from Bi_0.17Pb_0.3Sr₂Ca₂Cu₃O_y were obtained by a solid-state reaction in air at 835±5C. The best superconducting property of the as-prepared samples shows a one-step transition of a.c. susceptibility withT _c=109 K. Using this optimum sintering temperature and keeping the temperature fluctuation less than 5C, we have prepared pure Bi(Pb)2223 single-phase samples with good reproducibility.     

Balancing MXene Surface Termination and Interlayer Spacing Enables Superior Microwave Absorption

Surface chemistry and interlayer engineering determines the electrical properties of 2D MXene. However, it remains challenging to regulate the surface and interfacial chemistry of MXene simultaneously. Herein, simultaneous modulation of Ti₃C₂T_x MXene surface termination and layer spacing by alkali treatment are achieved. The electrical and electromagnetic properties of Ti₃C₂T_x are investigated in detail with respect to KOH and ammonia concentration dependence. A high concentration of KOH caused the Ti₃C₂T_x layer spacing to expand to 13.7 Å and the surface O/F ratio to increase to 33.84. Because of its weaker ionization effect, ammonia provides finer tuning compared to the drastic intercalation of KOH with a thorough sweeping of the F-containing groups. Ti₃C₂T_x is enriched with conductive -OH termination after ammonia treatment, which achieves an effective balance with the increased interlayer resistance. Therefore, NH₃H₂O-Ti₃C₂T_x achieves broad-band impedance matching and exhibits an efficient microwave loss of −49.1 dB at a low thickness of 1.7 mm, with an effective frequency bandwidth of 3.9 GHz. The results herein optimize the electrical properties of Ti₃C₂T_x using surface and interfacial chemistry to achieve broad microwave absorption, providing a framework for enhancing the electromagnetic wave loss of intrinsic MXene.