易燃易爆气体浓度智能监测仪的设计

为了对易燃易爆气体浓度进行检测,以便给人们提供一个安全、舒适的场所,设计了一个可实现对天然气、煤气、烟雾等易燃易爆气体浓度超标时自动语音示警的智能检测系统。文中给出了硬件结构,详细的阐述了软件设计流程,实验测试结果令人满意。该系统基于SPCE061A单片机和MQ-2传感器等成本较低的电子器件而设计,其硬件结构简单,具有体积小、性价比高、且灵敏度高等特点,可以应用到各类场所,具有广阔的应用前景。     

电磁波与材料相互作用探讨

 探讨了电磁波与材料相互作用,强调在现代科学研究中以Maxwell方程组为基础的电磁场理论的中心作用.以微波加热、超材料特性及超材料传感器为例,简要综述了国内外的研究现状,并介绍了云南大学信息学院在这方面的工作.     

基于ZnO/SiNWs异质结阵列的电容式湿度传感器

采用湿法化学刻蚀方法制备硅纳米线（SiNWs）,对其进行快速热退火处理,利用水浴法在SiNWs表面生长氧化锌（ZnO）纳米线,制备了ZnO/SiNWs异质结湿度传感器.采用扫描电子显微镜（SEM）和X射线衍射仪（XRD）分析了ZnO/SiNWs异质结的表面形貌和结构.测试了ZnO/SiNWs异质结湿度传感器不同湿度环境的电容响应,分析了它的工作机制.测试结果表明：传感器具有相对较大的灵敏度,较短的响应时间,较好的重复性、湿滞特性和稳定性,从而说明ZnO/SiNWs异质结在湿敏领域有很好的应用前景.     

贵金属掺杂纳米偏锡酸锌气敏性能及其机理分析

运用共沉淀法制备出纳米ZnSnO3粉末,X射线衍射仪(XRD)分析为纯的ZnSnO3相,透射电镜(TEM)分析表明粒度达到纳米级.利用传统的旁热厚膜制备工艺制备了纯ZnSnO3及其掺杂贵金属的气敏传感器,测试了气敏性能.通过对气体吸附机理和扫描电子显微镜(SEM)对敏感层的分析解释气敏性能提高的原因.结果表明: Ag+、Pd2+的掺杂可提高器件对C2H5OH的灵敏度,对H2敏感度的提高达到15倍以上.掺杂阻碍了基体晶粒的长大,使其表面不规则且有较多气孔,这是气敏性能提高的主要原因.     

Activity Recognition with Smartphone Sensors

The ubiquity of smartphones together with their ever-growing computing,networking,and sensing powers have been changing the landscape of people＇s daily life.Among others,activity recoginition,which takes the raw sensor reading as inputs and predicts a user＇s motion activity,has become an active research area in recent years.It is the core building block in many high-impact applications,ranging from health and fitness monitoring,personal biometric signature,urban computing,assistive technology,and elder-care,to indoor localization and navigation,etc.This paper presents a comprehensive survey of the recent advances in activity recognition with smartphones＇ sensors.We start with the basic concepts such as sensors,activity types,etc.We review the core data mining techniques behind the main stream activity recognition algorithms,analyze their major challenges,and introduce a variety of real applications enabled by activity recognition.     

A review on SnFe2O4 and their composites: Synthesis,properties, and emerging applications

Tin ferrite (SnFe₂O₄) and their composites have been extensively studied due to their unique functional properties including appealing electronic band structure, good chemical stability, high magnetization, excellent biocompatible and earth-abundant nature. Over the past few years, SnFe₂O₄ and their composites have been well designed and investigated for various kind of applications. In this review, the most important methods for SnFe₂O₄ and their composites synthesis, such as co-precipitation, hydrothermal, solvothermal and sol-gel techniques are summarized. It is important to emphasize that this review mainly focuses on the application of SnFe₂O₄ and their composites for environmental remediation, lithium-ion batteries and hydrogen peroxide sensors, which are discussed in detail for the first time. Apart from that, the key factors and essential means to improve their performance and functionality are systematically reported. Finally, the development prospect and challenge of SnFe₂O₄ and their composites are introduced. It is anticipated that this review will be helpful in development of SnFe₂O₄ and their composites with ameliorated performances for practical application in various fields.