新型红外二氧化碳传感器

本文介绍了一种具有不切光单光束结构的新型红外二氧化碳传感器，该传感器基于朗伯－比尔吸收定律，采用光源稳流，附加误差补偿与单片机数据处理及选用高性能红外探测器等技术，能够对二氧化碳气体进行准确有效的探测和分析。     

新型声表面波气体传感器

介绍了声表面波（SAW）气体传感器的工作原理及器件制作，提出了1种表面波SO2传感器，它采用三乙醇胺（TEA）覆盖薄膜，分辨率可达70×10－9。还讨论了SAW气体传感器的稳定性、可靠性、灵敏度及选择性等问题，并给出了有关的实验结果。     

硫化氢气体传感器研究

随着科学技术的发展,在科研与生产中,使用气体做原料、燃料情况增多,这些气体比如硫化氢是有毒的,危害性很大,它们在使用与运输中易造成大气和环境污染,危害人类,因此对于各种气体的检测和控制就更重要。近年来,传感器在朝着灵敏、精确、适应性强、小巧和智能化的方向发展。在这一过程中,人们开始综合分析光学气体检测基础上,利用硫化氢气体对光谱的吸收特性,采用光谱吸收法检测硫化氢气体浓度。采用宽带光源波长调制技术设计检测硫化氢气体浓度传感器,利用光源光波对气体吸收选择性,增大了气体吸收灵敏度。降低了交叉灵敏度,解决了传感器中毒等关键技术问题。所以．研究硫化氢气体的检测方法与气体传感器就成为重要课题了。     

固态气体传感器

固态气体传感器Ｐ．Ｔ．Ｍｏｓｌｅｙ１．引言二十世纪中，伴随着社会工业化进程的不断发展，气体监测技术应运而生。有机燃料和其他化学物质已逐渐成为人们日常生活和工业生产中不可缺少的一部分，但与此同时，也带来了环境污染等不良后果。环境保护是眼下最热门的话题之...     

一种高灵敏度光声光纤SO2气体传感器的研究

基于气体光声效应原理，研究了一种高灵敏度光纤SO2气体浓度传感器。用染料激光器作为激励源，激励出光声信号，采用光纤位移传感器测量光声信号。设计了光学长程装置以提高光声腔的灵敏度。用此装置测量SO2气体浓度，给出了实验数据并对结果作了分析。     

半导体气体传感器新近发展动态

本文简要介绍了国内外半导体气体传感器的生产情况,评述了半导体气体传感器目前发展动向。认为超微粒技术、L-B 膜技术对促进气敏技术很有意义。本文还强调气敏基础研究的重要性,提出从表面和催化伪度出发研究气敏材料是有意义的,并讨论了催化和气敏的关系。     

智能气体传感器研究

本文用具有不同特性的非选择性气敏元件组成气敏阵列，结合神经网络模式识别和信息处理技术，进行混合气体识别和浓度定量检测。着重说明神经网络模式识别法在气敏阵列信号处理中的应用。     

新型气体检测仪的技术分析

气体检测仅是由一个具有部分专一性的电子化学传感器阵列和一个合适的模式识别系统组成,能够识别单一的或复合的气味,还能够用于识别单一成分的气体、蒸汽或其混合物。它是当今快速发展起来的一种分析、识剔和检测复杂嗅味和大多数挥发性气体的仿生检测仪器。     

基于非线性 PCA的微气体传感器阵列信号处理

在线性叠加模型基础上提出了气体传感器对混合气体的非线性叠加模型,并引入了非线性主成分分析(Nonlinear Principal Component Analysis,NLPCA)法对微传感器阵列的信号进行处理。使用该模型对由4个微热板式气体传感器组成的阵列的信号进行了分析,对照基于线性叠加模型的主成分分析法(Principal Component Analysis,PCA)的识别结果,说明该方法能够提高对混合气体识别和量化的准确度。     

Bias-heating recovery of MWCNT gas sensor

A sensor was made using Au/Cr electrodes on a glass substrate and a thin carbon multiwall nanotube film printed between them. A bias-heating method was used completely to desorb gas molecules and restore its initial conductance. The temperature of the thin carbon nanotube film varied depending on the magnitude of the voltage used, and this relationship was investigated. After being used to detect NO₂, the sensor returned to its initial conductance. This method enables complete recovery without additional processing steps, such as the fabrication of heat structure and ambient heating.     

Fabrication and characterization of Ga-doped ZnO nanowire gas sensor for the detection of CO

We demonstrate an efficient CO sensor using Ga-doped ZnO (GZO) nanowires (NWs). Various GZO NWs are synthesized with Au catalysts on sapphire substrates by hot-walled pulse laser deposition. The deposition temperature of ZnO NWs was in the range of 800-900 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) characterizations indicate that the obtained NWs have the well-crystallized hexagonal structure with customized Ga-doping concentration of 0-5 wt.%. The NWs have the diameter of about 50 nm and the length of about 8 µm. After depositing the Ag electrodes on both sides of the NW cluster, the resistance change is checked with the exposure to CO gas in the self-designed gas chamber that can facilitate the detection of the resistance change and the control of gas flow as well as temperature. The detected resistance modulations are 1.0 kΩ and 83.2 kΩ in the cases of 3 wt.% GZO and pure ZnO NW clusters, respectively, indication that we successfully customize the sensitivity of the gas sensors by controlled doping.     

Contribution of electron tunneling transport in semiconductor gas sensor

It was found that thin film devices derived from SnO₂ sols by spin-coating method showed unique thermal behavior of electric resistance in air involving a temperature region where resistance was independent of temperature. The temperature independent resistance region extended up to 400 °C, replacing a region of temperature-conventionally dependent resistance, as film thickness increased. Such unique behavior of resistance was observed also for a brush-coated device but not for screen-coated thick film devices or disk-type device, suggesting that the absence of mechanical forces applied during device fabrication favored the occurrence of the unique behavior. It was shown that the unique behavior could be well accounted for by postulating a combination of electron tunneling transport and conventional migration transport. Calculation of tunneling probability based on a simple model allowed estimating that electron tunneling transport can take place between oxide grains with a probability of 0.01 or larger if a gap in between is narrower than 0.01 nm.     

Improved zinc oxide film for gas sensor applications

Zinc oxide (ZnO) is a versatile material for different commercial applications such as transparent electrodes, piezoelectric devices, varistors, SAW devices etc because of its high piezoelectric coupling, greater stability of its hexagonal phase and its pyroelectric property. In fact, ZnO is a potential material for gas sensor applications. Good quality ZnO films were deposited on glass and quartz substrates by a novel CVD technique using zinc acetate as the starting solution. X-ray diffraction confirmed the crystallinity of the zinc oxide film and SEM study revealed uniform deposition of fine grains. Undoped ZnO films were used for detection of dimethylamine (DMA) and H₂ at different temperatures by recording the change in resistivity of the film in presence of the test gases. The response was faster and the sensitivity was higher compared to the earlier reported ZnO based sensors developed in our laboratory. The main objective of this work was to study the selectivity of the ZnO film for a particular gas in presence of the others. The operating temperature was found to play a key role in the selectivity of such sensors.     

基于塞贝克效应的半导体气敏传感器的研制

利用塞贝克效应研制成功ZnO半导体气敏传感器。这种新型传感器能够输出0-100mV的直流电压,对于信号的放大与处理将十分方便。在实验中对20×10-6NO2气体进行检测,结果表明:传感器的输出电压(温差电动势),随着待测气体浓度而变化。因此,利用温差电效应制作气敏传感器是一条完全可行的新思路。     

Dynamic response of a semiconductor gas sensor analysed with the help of fuzzy logic

Semiconductor gas sensors are essentially not selective to detect a single chemical species in a gaseous mixture and also the response of the sensor in most cases is influenced by the variations of ambient humidity and temperature. One of the solutions is the analysis of the dynamic response of a single sensor with modulated temperature. For the non-linear output signal the fast Fourier transform transform was calculated. The zero-order amplitude and the phases of higher harmonics were selected. These quantities served as input data for the fuzzy model of the sensor. The hybrid fuzzy sensor model, based essentially on Takagi-Sugeno-Kang (TSK) theory, comprised a two-level optimization algorithm. The authors elaborated that algorithm, utilizing conjugate gradient and genetic algorithm methods. At the output of the fuzzy model the concentrations of ethanol with minimized influence of humidity variations were obtained.     

气/固两相流固相浓度传感器的研究

设计了一种新型测量气／固两相流固相浓度的螺旋极板电容传感器，并通过实验得出提高传感器检测场灵敏度空间分布均匀性及克服边缘效应对检测精度影响的方法。     

Uniform ZnO nanorods can be used to improve the response of ZnO gas sensor

Uniform ZnO nanorods were synthesized in high-yield by using metal zinc powder as zinc source via a one-step facile hydrothermal process under mild conditions, in which cetyltrimethylammonium bromide (CTAB) with ordered chain structures acted as the conversion of Zn powder into ZnO nanorods. The characterization results show that the as-synthesized products were structurally uniform and have diameters of 40–80 nm. Gas sensing properties studies show that ZnO nanorods exhibit more excellent response and stability to ethanol than that of ZnO nanoparticles. After working continuously for 50 days, the sensitivity of ZnO nanorods still retained 7.3, whereas, the ZnO nanoparticles showed only 1.0. The facile preparation method and the improved properties derived from typical rods-like nanostructure are significant for the future applications of gas sensing material.