An electronic nose for amine detection based on polymer/SWNT-COOH nanocomposite

An electronic nose (e-nose) system based on polymer/carboxylic-functionalized single-walled carbon nanotubes (SWNT-COOH) was developed for sensing various volatile amines. The SWNT-COOH dispersed in the matrix of different polymers; namely, polyvinyl chloride (PVC), cumene terminated polystyrene-co-maleic anhydride (cumene-PSMA), poly(styrenecomaleic acid) partial isobutyl/methyl mixed ester (PSE), and polyvinylpyrrolidon (PVP), were deposited on interdigitated gold electrodes to make the gas sensors. The response of these sensors to volatile amines was studied by both static and dynamic flow measurements. It was found that all sensors exhibited behaviors corresponding to Plateau-Bretano-Stevens law (R2 = 0.81 to 0.99) as the response to volatile amines. Real-world application was demonstrated by applying this e-nose to monitor the odor of sun-dried snakeskin gourami that was pre-processed by salting-preservation. This electronic nose can discriminate sun-dried fish odors with different stored days using a simple pattern recognition based on the principal component analysis (PCA).     

A gradient microarray electronic nose based on percolating SnO(2) nanowire sensing elements

Fabrication, characterization, and tests of the practical gradient microarray electronic nose with SnO(2) nanowire gas-sensing elements are reported. This novel device has demonstrated an excellent performance as a gas sensor and e-nose system capable of promptly detecting and reliably discriminating between several reducing gases in air at a ppb level of concentration. It has been found that, in addition to the temperature gradient across the nanowire layer, the density and morphological inhomogeneities of nanowire mats define the discriminating power of the electronic nose.     

Hybrid optical-electrochemical electronic nose system based on Zn-porphyrin and multi-walled carbon nanotube composite

In this work, we have enhanced the capability of an e-nose system based on combined optical and electrochemical transduction within a single gas sensor array. The optical part of this e-nose is based on detection of the absorption changes of light emitted from eight light emitting diodes (LEDs) as measured by a CMOS photo-detector. The electrochemical part works by measuring the change in electrical resistivity of the sensing materials upon contact with the sample vapor. Zinc-5,10,15,20-tetra-phenyl-21H,23H-porphyrin (ZnTPP) and multi-walled carbon nanotube (MWCNT) composite was used as the sensing materials based on its good optoelectronic properties. This sensing layer was characterized by UV-Vis spectroscopy and atomic force microscope and tested with various VOC vapors. Density functional theory (DFT) calculations were performed to investigate the electronic properties and interaction energies between ZnTPP and analyte molecules. It can be clearly seen that this hybrid optical-electrochemical electronic nose system can classify the vapor of different volatile organic compounds.     

基于CFX和Workbench的数值仿真技术

为分析超音速风洞中飞行器模型支撑机构工作可靠性,利用Ansys CFX和Workbench软件,研究了此结构的强度和刚度.首先在CFX中进行外流场分析,再将得到的固体表面温度和压力导入Workbench中进行热结构耦合分析,从而实现了流热固耦合仿真分析,得到结构应力和变形.该方法涉及流场、温度场和应力场,可以大大提高数值仿真效率,对于CAE工程分析人员具有很大的借鉴意义.     

嵌入式设备电源控制系统的CAN通信软硬件设计

为解决电源监控系统中存在的数字化程度低、实时性差、准确度和可靠性低等问题,在研究CAN协议的原理及应用技术的基础上,采用外挂Microchip MCP2515 CAN控制器的设计思想,完成基于AVR单片机的CAN通信软硬件设计,满足电源控制系统策略的需要。该文给出CAN总线的整体结构及控制器、收发器等组成部分硬件及软件的设计与实现,并对系统进行网络负载分析及实时性分析。实际运行表明:该系统可实现报文的发送、接收等功能,可靠性强、通信实时性好。另外,电气隔离电路的设计,进一步提高系统的抗干扰能力;同时,软件设计部分采用自顶向下的模块化设计方法,增强系统的可移植性。     

Enhanced dielectric properties of PVA/PEDOT:PSS/MnO2 based composites for electronic applications

Journal of Materials Science: Materials in Electronics - Polymer composite (PC) films comprising polyvinyl alcohol (PVA) and poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)...     

Revenue management and demand fulfillment: matching applications,models, and software

Recent years have seen great revenue management successes, notably in the airline, hotel, and car rental businesses. Currently, an increasing number of industries, including manufacturers and retailers, are exploring ways to adopt similar concepts. Software companies are taking an active role in promoting the broadening range of applications. Additionally technological advances, including smart shelves and radio frequency identification (RFID), are removing many of the barriers to extended revenue management. The rapid developments in supply chain planning and revenue management software solutions, scientific models, and industry applications have created a complex picture, which is not yet well understood. It is not evident which scientific models fit which industry applications and which aspects are still missing. The relation between available software solutions and applications as well as scientific models appears equally unclear. The goal of this paper is to help overcome this confusion. To this end, we structure and review three dimensions, namely applications, models, and software. Subsequently, we relate these dimensions to each other and highlight commonalities and discrepancies. This comparison also provides a basis for identifying future research needs.     

Thin film metallic glasses in optoelectronic,magnetic, and electronic applications: A recent update

Thin film metallic glass (TFMG) is a new class of metallic thin film with unique characteristics, including smooth surface, absence of grain boundaries, second-order glass transition, annealing-induced amorphization, soft magnetic properties, and high thermal stability. Hence, with these properties, TFMGs are found very useful and promising in many areas, ranging from structural, biomedical to electrical components. This review provides an update on future challenges and opportunities associated with the further development of TFMG.     

视频分划的自动瞄准技术与应用研究

基于光学分划原理提出了视频分划技术,在此基础上提出了新的自动瞄准技术,并详述了视频分划技术中视频竖线、横线和十字线的生成技术,分析讨论了视频分划技术用于自动瞄准的实现原理及瞄准的精度,还将该技术应用于高速、高精度钢卷尺自动瞄准切零位系统中,取得了显著的成效.基于其具有的超越光学分划技术的优越性能,视频分划技术在自动瞄准、自动测量、自动识别及自动存储等多种实际工程应用中都有广阔的应用前景.     

基于组态技术的测控软件开发及测试

以电站综合自动测控系统为对象,研究了基于组态技术的综合测控系统,详细论述了系统的基本软件结构、基本数据库属性和数据结构定义、基于组态技术的绘图模块及组态通信模块等内容.采用标准化的软件测试技术设计了组态系统的软件正交测试模块,该技术具有二次开发简便、开发周期短、通用性强等特点.     

基于组态软件与DDE技术的流量计校准系统研制

在分析流量标定装置的标定原理与结构基础上,将标准表法和标准体积法综合在一套流量校准装置中,扩大了应用范围,提高了检定效率。完成恒压供水系统、数据采集、标准流量计及控制执行等电路的配置,建立系统的数学模型,进行Matlab仿真分析,采用组态王软件开发流量计检定系统,运用DDE技术完成了Matlab与组态间的动态数据交换,通过编程实现流量装置和流量计的检定、数据存储以及历史数据报表等功能,较好地实现在线实流校准的仿真。实验调试表明:流量计校准装置的准确度为0.3,能较好地实现流量校准系统的控制、数据采集、处理分析的自动化。     

一种嵌入式Web服务器的远程测控系统

针对目前工业现场大量8位普通微处理器尚未接入Internet的现状，本文详细介绍了基于51单片机的嵌入式Web服务器，并由此构建了基于二维精密工作平台的远程测控系统。经实践检验，此方案切实可行。     

A cost- and energy-efficient embedded system design based on instruction execution frequencies

In this paper, an embedded system that takes into account the frequency of the executed instructions to reduce memory space and save energy consumption is proposed. The object codes are split into the frequently executed instructions and the infrequently executed instructions (INFIs) by analyzing the trace files of applications. To reduce the use of memory space, the dictionary-based method is used to compress INFIs. To take into account energy consumption, the top-executed instructions are selected to encode as shorter codewords and wrapped into a pseudo instruction. When a pseudo instruction that contains several codewords is fetched, it can be decompressed to several continuous instructions to reduce the number of memory accesses. In addition, to further reduce energy consumption, a multiple reference table design is proposed to make a pseudo instruction contain more encoded codewords by shortening the length of an encoded instruction. From the simulation results, the proposed design that uses one 256-instruction reference table reduces the energy consumption about 50.4% compared to the dictionary-based method. In addition, to show the improvement of energy consumption for the proposed multiple reference table method over that using one reference table, we also show the simulation results of a design with two 256-instruction reference tables which shows less energy use than a design with one 512-instruction reference table by 12.1%.