声表面波气体探测器控制电路设计与优化

声表面波气体探测器包括声表面波传感器阵列、富集器、气泵、温度控制器等部件。基于8051单片机为探测器设计了一套控制电路并编写了控制程序,通过调节控制电路改变探测器的工作参数,分别测试了采样气泵流速、富集器的吸附时间与解吸附时间对声表面波气体探测器性能的影响,为优化探测器性能提供了实验依据。     

本期摘要

地震微观前兆预报网络系统设计研究（1）——地震模型;医用电子鼻气体传感器阵列优化方法;基于相位检测的声表面波传感器变送电路设计.     

一种SAW气体传感器的设计考虑

声表面波气体传感器的最终成功既取决于化学界面膜的性能,也取决于声表面波器件设计的最佳化。给出了声表面波气体传感器的设计考虑。     

声表面波技术在化学战剂检测中的研究及发展

该文通过对目前世界各国SAW技术检测化学战剂研究发展状况的回顾,系统介绍了SAW传感器中膜材料的选择、灵敏度和温湿度、干扰气体、气体流速等因素对检测的影响,以及阵列式SAW传感器的检测方法,尤其是联合化学战剂检测器JCAD在化学战剂检测中的实际应用,并对今后声表面波技术检测化学战剂的研究发展前景提出了初步看法.     

声表面波阵列传感器研究进展

声表面波(SAW)阵列传感器具有许多独特的优点,目前已成为检测化学毒剂的重要手段之一:近年来,随着以SAW阵列传感器为主要技术的电子鼻的发展,使得SAW阵列传感器在食品检测、环境治理等领域得到了广泛应用.对SAW阵列传感器的发展及其应用进行了综述.     

声表面波NO2传感器的研究进展

NO2是一种主要的大气污染物,同时对人体健康也有较大的危害,针对其进行检测的传感器的研究和开发就显得十分重要.声表面波气体传感器具有便携性、快速响应、高灵敏度、高稳定性、低成本等特点,引起了国内外相关研究者的广泛关注.简要介绍了声表面波(SAW)气体传感器工作的基本原理、传感器敏感膜与NO2气体的作用机理以及SAW-NO2气体传感器的两种结构类型,综述了SAW-NO2气体传感器常用的几种敏感膜材料,并对SAW-NO2气体传感器的发展趋势做了展望.     

声表面波气体传感器

在化学研究领域,声表面波器件得到了越来越多的注目.声表面波延迟线振荡器的振荡频率对沉积在其表面的薄膜层非常敏感,选择适当的气体吸附材料涂覆在器件的表面,声表面波延迟线振荡器就可用于制成十分敏感的气体传感器。当涂覆层性能优良时,传感器可检测出浓度为0.01—0.1ppm水平的特定气体成份。     

用于气体检测的声表面波振荡电路设计

分析了声表面波(SAW)谐振器的性能和特点,对基于双端谐振型声表面波器件进行了振荡电路设计,采用RP1308、B433及Q284三种型号的声表面波谐振器进行了电路调试.测试结果表明,该电路能在固定频率起振,且频率跳变能够控制在30 Hz以下.本电路能够应用于多种不同谐振频率的双端谐振型声表面波气体传感器,具有广泛的应用前景.     

基于SAW表面气液相效应和GC分离柱的气敏传感器

限于传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难和选择性差、重复性差以及再生性差等问题,本研究提出一种基于压电基底表面气体气液相转换效应机理的瑞利波传感器。在此基础上开发了一种基于瑞利声表面波传感器和气相色谱（GC）分离柱的便携式气体检测系统。最后实验论证了方案的可行性,初步的实验结果表明该系统具有分析时间短、选择性好、灵敏度高,可检测ppb（10^-9）浓度的混合VOCs以及成本低等优势,显示其在痕量挥发性有机气体检测和分析应用上有良好的潜力和前景。     

声表面波气体传感器的设计

本文阐述了声表面波气体传感器的工作原理,并详细介绍了该类传感器的设计思想。     

Solvation,transduction and independent component analysis for pattern recognition in SAW electronic nose

This paper revisits the fundamental basis for signal generation in polymer coated SAW vapor sensors and applies the independent component analysis (ICA) for feature extraction from the SAW sensor array data to explore whether the independent components could represent analyte-specific solvation parameters and whether they could form the feature vector for reliable pattern classification. Thermodynamic partitioning of analytes between vapor and polymer phases is treated as independent contributions from different solvation mechanisms, each associated with characteristic ‘environment swap’ energy. The overall equilibrium partition coefficient of an analyte is modeled as product of partial partition coefficients associated with different solvation mechanisms. The polymer films on SAW devices are treated to be acoustically thin. The theory of signal generation accounts for effects from both the mass as well as the viscoelastic loadings. It explains the signal amplification factor due to viscoelastic effects, and models the sensor signal to be proportional to the equilibrium partition coefficient. Thus, the logarithmic signal becomes a linear combination of the partial free energies associated with various solvation mechanisms. A linear-solvation-energy relationship (LSER) like factorization is assumed for the partial free energies where the latter are expressed as product of analyte and complimentary polymer associated solvation parameters. The problem of sensor array signal analysis is then treated as a blind source separation problem with the analyte solvation parameters being the independent sources, the polymer solvation parameters being the mixing weights and the log(signals) being the measured variables. The FastICA algorithm with Gram-Schmidt orthogonalization is applied to determine independent components. The principal component analysis (PCA) is done as pre-processing step for ICA. An experimental SAW sensor array data available in the literature [Rose-Pehrsson et al., Anal. Chem. 60 (1988) 2801–2811] is used to seek validation for our approach, and to examine the role of ICA in SAW sensor array signal processing. In brief, the paper establishes a direct relationship between the independent components and the analyte solvation parameters, and presents ICA as an effective method for feature extraction for pattern recognition in SAW electronic noses.     

结合金属膜的YZ-LiNbO3压电基片上声表面波陀螺效应分析

在声表面波陀螺效应作用过程中,由于哥氏力的作用比较微弱,导致现有的声表面波陀螺仪的检测灵敏度极低。为了改善哥氏力作用,在声表面波传播路径上分布金属点阵以增加质量负载,将有可能获得良好的灵敏度性能。本文结合研究层状介质中声波传输特性的方法对YZ-LiNbO3压电基片上的金属膜层对陀螺效应的影响做了理论计算。对比分析有无金属膜层的压电基片中陀螺效应的大小,以及不同金属材料对陀螺效应的影响作用,验证了用布置重金属点阵的方法来提高行波模式声表面波陀螺仪检测灵敏度的可行性,从而为高性能行波模式声表面波陀螺仪的研制奠定理论基础。     

基于极化和复用的SAW传感器阵列

针对谐振型声表面波(SAW)温度传感器难以灵活构建较大规模传感器阵列的问题,结合天线技术,基于极化和复用的思想,通过频分、时分、空间角度分集和极化,研究实现较大规模的SAW传感器阵列的方法。并通过实际测试,实验结果表明:在略微增加发射天线数目的代价下,阵列规模迅速增大,阵列中的传感器元能得到有效辨识。实验结果验证了设计方法的可行性。     

一种声表面波液体密度传感器的实验研究

介绍了一种新型的表面波(SAW)液体密度传感器的结构,并对其进行了理论分析和初步实验。结果表明:与传统的液体密度传感器相比,这种传感器具有结构简单、测量精度高、需用试样少等特点,具有广泛的应用前景。     

声表面波传感器Q值改善的理论分析与实验结果

报道了带变迹叉指换能器（IDT）和倾斜金属反射栅的高Q值Y型声表面波（SAW）质量沉积传感器。用P矩阵方法分析了三种不同传感器的通带纹波。分别在振荡和非振荡模式下比较了这些传感器的通带纹波和Q值。分析了获得高Q值的原因。理论和实验结果表明：均匀孔径无反射栅的传感器旁瓣抑制为10dB，振荡模式下其Q值为5289；通过孔径变迹设计，传感器的旁瓣抑制和Q值分别改善到25dB和8689；而对孔径变迹并加入倾斜反射栅的传感器，这两个参数提高到25dB和12477。非振荡模式下带反射栅的传感器比没有反射栅器件的通带纹波约低2dB。因此，变迹IDT和金属反射栅的应用是SAW质量传感器Q值的改善的两个重要因素。由于Q值改善，质量沉积灵敏度达到5.24GHz?cm2/g     

Integration of Microfluidics With a Love Wave Sensor for the Fabrication of a Multisample Analytical Microdevice

A novel approach for multisensing has been developed based on the integration of a parallel-channel microfluidic module with a surface acoustic wave (SAW) sensor chip. The microfluidic module was used to compartmentalize the surface of a single SAW sensor into $N$ equal subareas in order to deliver and detect multiple samples on the sensor. The design concerns and fabrication procedure using soft lithography of polydimethylsiloxane are described. Successful demonstration of a four-channel module is reported, along with a sensitivity evaluation and comparison with a standard flow cell used so far. Very promising results were revealed during the tests concerning the system's operation with liquid samples. The reliability and reproducibility of the results in all four subareas render the proposed setup very suitable for biological testing and screening of various biomolecules in an array format.$ hfill$[2008-0031]      

声表面波NO_2传感器敏感膜研究进展

由于工业检测、环境监测、医学监测等领域的需求,高性能NO2传感器得到了广泛的研究。声表面波传感器技术的发展为研发高灵敏度、高稳定性、响应快速、小型化的NO2传感器提供了极大的潜能。总结了近30年来声表面波NO2传感器敏感膜的研究现状,并根据现有的研究和传感器的应用需求,深入探讨了声表面波NO2传感器敏感膜面临的挑战和发展趋势。     

基于SAW器件的微间隙压力监测传感器

声表面波SAW(Surface Acoustic Wave)器件能进行无源无线通信,为微间隙等特殊环境下物理量的测量提供了新的解决思路.研究设计了一种基于声表面波延迟线的接触应力传感器.围绕微间隙环境,研究了声表面波器件的结构类型,并确定压力监测的技术方案;根据设计原理,设计一种新型声表面波传感器,并利用有限元分析法对压电基片进行应力仿真;将设计出的传感器进行实验测试并提出温度补偿.通过对声表面波传感器设计的探究,验证了利用声表面波传感器实现微间隙压力监测的可行性.     

Coupling coefficient determination based on simulation and experiment for ST-Cut quartz saw delay-line response

This paper used the theoretical calculation to simulate the response of surface acoustic wave (SAW) delay-line on quartz substrate and then compared to the experimental results. The coupling coefficients affected by operation frequency as well as aperture length were built up by experimental data analysis. Based on the experimental values of these two parameters, the device-coupling coefficient was defined. This method is new and we has not found in other document. In addition, it improves the simulation results and helps the analysis process more comprehensive. This study developed ST-cut quartz SAW delay-lines with gold inter-digital transducer (IDT) operating at 39.5 and 78.9 MHz corresponding to 80 and 40 μm of the wavelength. The differences of aperture length in IDT designs were investigated to help understand the effects of this parameter on SAW sensor response. The maximum error of operating frequency is 1%; of insertion loss is 4.25 and 3.13% for bandwidth. The larger of the insertion loss error is expected owing to the result of mathematical approximation and the quality of quartz substrate. The simulation results agree with the experimental results shows that the simulation method can apply to quartz-based SAW delay-line as well as for other material based SAW delay-line applications. The results help understand more about the parameters which effect the insertion loss, operating frequency and bandwidth. It should be very useful for IDT design in specific, SAW sensor and SAW filter design in general.