声板波传感器及其应用

讨论了可用于液相环境下测量的声板波（ＡＰＭ）传感器的工作原理,并介绍了该传感器在物理、化学和生物检测中的应用。     

Lateral field excited Y-cut langasite bulk acoustic wave sensor

Previous studies have shown that lateral field excited (LFE) devices on AT-cut quartz are sensitive to liquid electrical property changes. AT-cut quartz LFE devices have low piezoelectric coupling factors. To further improve electrical sensitivities of LFE sensors, it is necessary to study LFE sensors based on other piezoelectric materials with higher coupling factors. In this paper, LFE sensors on Y-cut langasite, which has twice the higher piezoelectric coupling factor of AT-cut quartz, are investigated. Several Y-cut langasite LFE sensors are designed, fabricated, and tested. The experimental results show that the devices are over 6 times more sensitive to liquid conductivity changes and about 2.5 times more sensitive to liquid permittivity changes compared to AT-cut quartz LFE devices. It was also found that the Y-cut langasite LFE devices are about 1.3 times more sensitive to changes in liquid acoustic viscosity compared to the AT-cut quartz LFE devices.     

水平剪切声板波的激发机理及其特性研究

水平剪切声板波(SH-APM)是在板状固体结构中传播的一种声波,其质点振动垂直于传播方向和界面法线。针对SH-APM的激发机理和激发特性两个方面展开研究。首先通过分析压电介质的Christoffel方程组解耦情况来研究SH-APM的激发机理,推导出为了在压电板上激发出SH-APM,压电基片的材料常数所必须满足的条件;然后在此基础上,建立了SH-APM器件的理论分析模型,并以PZT-5H压电陶瓷为例,研究了SH-APM的激发特性,包括激发模态、传播速度、激发效率、振动位移等;最后,通过实验以及理论计算与相关文献对比,证明了理论模型的正确性及研究结果的有效性。     

电磁流量计三值方波励磁信号的控制

电磁流量计是一种根据法拉第电磁感应定律来测量管内导电介质体积流量的感应式仪表。本文在分析电磁流量计的励磁信号种类和特点的基础上,选择了低频三值矩形方波作为电磁流量计的励磁信号,设计了电磁流量计的励磁线圈,并分析了线圈的物理和几何参数,在此基础上设计励磁系统硬件电路,包括电源、固态继电器、控制器Labjack的选型和控制方法等。最后设计了低频三值方波的控制程序,为电磁流量计提供了一种性能良好的励磁控制方案。     

新型水晶体波谐振式膜厚传感器

介绍一种利用B模式厚度切变体波工作的新型水晶谐振式膜厚传感器。它采用修正式SC切型 ,以同线场电极激励。它可以在 10～ 2 80℃范围内工作 ,其测量范围为 0 .1～ 80nm ,准确度为 0 .0 2nm。     

An acoustic wave sensor for the hydrophilic fluoride

A new acoustic wave sensor to detect and quantify fluoride, one of the most hydrophilic anions, is proposed. Meso-octamethylcalix[4]pyrrole (OMCP) and seven of its derivatives were evaluated as piezoelectric quartz crystal coatings. Some of these sensors experienced appreciable coating leaching under a water flow, while others did show a very small sensitivity to fluoride. As the OMCP-naphthoquinone sensor was very sensitive to fluoride and did not lose a significant amount (α = 0.05) of coating during eight weeks, it was selected among all the others. A piezoelectric crystal coated with an amount of OMCP-naphthoquinone that produced a frequency decrease of 22 kHz showed a linear calibration range that extended up to 80 mg L⁻¹, within which sensitivity to fluoride was 0.45 Hz L mg⁻¹_, and was able to detect fluoride at the concentration of 3.66 mg L⁻¹. This sensor was used to determine fluoride in commercial fluoride tablets, and the result found was not statistically different (α = 0.05) from the value provided by the manufacturer.     

基于倾斜AlN薄膜的体声波质量传感器的制备及性能分析

提出通过改变溅射气压获得倾斜于C轴的AlN薄膜的制备方法,探讨了倾斜AlN薄膜的生长机理。以3对交替沉积的Ti—Mo金属层为布拉格声学反射层,采用MEMS工艺制备了基于倾斜AlN薄膜的、以剪切模式振动的体声波液体传感器,并对器件的S11参数进行测试分析,得到传感器的中心频率为0.8GHz,表明该器件在生物液相检测领域具有一定的应用前景。     

Love wave hydrogen sensors based on ZnO nanorod film/36°YX-LiTaO3 substrate structures operated at room temperature

Love wave hydrogen sensors based on ZnO nanorod layers deposited on 36°YX-LiTaO₃ substrates have been studied. The ZnO nanorod layers are prepared by two steps: first, the seed layers, as well the guiding layers of the Love wave devices, are deposited by RF magnetron sputtering; second, the nanostructural layers, as well the sensing layers of the sensors, are grown by hydrothermal synthesis. Two kinds of ZnO layers have been analyzed by XRD, SEM and XPS. The XRD shows that both ZnO layers have (0 0 2) oriented wurtzite structures. The SEM results reveal that the morphologies of the deposited ZnO seed layers are continuous and compact, while the hydrothermal treated layers are with nanorods almost perpendicular to the substrate surfaces. Finally, the hydrogen sensing responses of the Love wave sensors activated by Pt catalysts are measured for various concentrations of hydrogen in synthetic air at room temperature. The results show that the sensors have high sensitivity and repeatability as the nanorod layers are optimized, such as the frequency shift 8 kHz toward 0.04% of H₂ in synthetic air is obtained while the height of the nanorod layer is about 2.1 μm and the central frequency of the sensor is about 125.5 MHz. The XPS analyses of the sensitive layers show that there are oxygen vacancies in the layers, so the oxygen vacancy model is used to explain the hydrogen sensing mechanism of the Love wave sensors.     

覆盖聚合物敏感膜的水平剪切型声表面波气体传感器机理分析

采用微扰理论分析了覆盖聚合物敏感膜的水平剪切型声表面波气体传感器(SH-SAW)的响应机理.以针对有机磷毒剂具有良好选择性的含氟多羟基聚硅氧烷(FPOL)膜材料为例,分析了聚合物膜厚以及传感器工作频率在敏感膜吸附气体时对传感器响应的影响.计算结果表明,SH-SAW气体传感器对于不同浓度的甲基磷酸二甲酯(DMMP)气体响应随FPOL膜厚和传感器工作频率的改变呈现非线性变化.为了获得线性特性的传感器响应及较小的声波衰减,在一定的DMMP气体浓度检测范围内,通过理论计算提取出了优化的FPOL敏感膜膜厚和传感器工作频率等参数.     

磁致伸缩纵向导波传感器中偏置磁场的优化设计

偏置磁场大小是磁致伸缩纵向导波传感器设计的关键参数之一,最佳偏置磁场的选择受到材料和激励条件的影响,故要求导波检测系统中偏置磁场可调节性好.目前使用的偏置磁场有两种,其中螺线管线圈产生的磁场信号干扰大,信噪比低,永磁体提供的磁场可调节性不佳.为此,提出一种偏置磁场可以调节的结构方案,并通过该方案研制了一种可以调节的偏置...     

光纤生物传感器中的探针匹配研究

对基于倏逝波激发的光纤生物传感器中光纤探针的模式匹配理论进行了分析,自行构建了一套基于倏逝波激发的光纤生物传感器系统,研究了光纤探针部分的模式匹配程度对该传感器系统灵敏度的影响。实验分光纤探针置于空气中和蒸馏水中2种情况进行,分别对五组具有不同纤芯半径的光纤探针进行检测,实验结果表明:系统的荧光信号检测信噪比与光纤探针纤芯半径的关系曲线基本与模式匹配理论曲线相吻合。     

微型热膜传感器的水下壁面剪应力标定研究

针对水下壁面剪应力的测量需求,建立了恒流模式下微型热膜传感器的剪应力测量与标定的数学模型,设计采用了扁薄矩形水槽剪应力发生装置,并在0 ～5 Pa范围内对传感器进行了测量标定实验.实验结果验证了测量与标定模型的正确性,标定实验的确定系数均超过了0.995,均方差保持在10-4量级,呈现良好的重复性与一致性,为水下壁面剪应力的测量应用奠定了重要基础.     

铁芯参数对磁通门输入输出特性影响分析

针对磁通门需要什么参数的软磁铁芯的问题,在分析磁通门数学模型基础上,得出了正弦激励条件下磁通门的最佳激励磁场为铁芯饱和磁场强度的槡2倍;以带磁滞的双曲正切函数拟合软磁材料磁滞回线,分析了饱和磁感应强度、饱和磁场强度、矫顽力、矩形比和退磁系数对输出二次谐波幅值和激励电流的影响,得出高灵敏度磁通门铁芯应具有高磁导率和矩形比,低饱和磁场强度、矫顽力和退磁系数;低功耗磁通门铁芯应具有高磁导率,适当的矩形比,低饱和磁感应强度、饱和磁场强度、矫顽力和退磁系数;最后通过对比两组六种不同铁芯的磁滞回线和双铁芯磁通门输入输出特性,验证了以上结论的正确性。     

基于光场耦合的时栅位移传感器设计

为了实现制造成本低、易加工、高精度的位移测量,设计了一种光场耦合式的时栅位移传感器.介绍了利用基于交变光场的两路驻波合成电行波信号,并通过鉴相的方式实现空间位移转换的测量原理;完成了传感器的结构设计,给出了传感器的系统框图,具体分析了信号处理电路的功能.实验结果表明:光场耦合式的时栅位移传感器在108 mm范围内误差为±0. 5μm.     

基于平面线圈的基波脉振磁场构造方法研究

为了减小电磁式时栅位移传感器的原始误差,提出了一种基于平面线圈的基波脉振磁场构造方法.通过研究现有电磁式时栅磁场构造方法和平面线圈磁场分布特性,利用各次谐波畸变率THD(Total Harmonic Distortion)最小的优化算法,得到平面线圈最优化布置参数,并且在数值分析和有限元分析软件中得到了验证.根据这些参数设置,设计了基于多匝方形平面线圈的新型电磁式时栅位移传感器.在150 mm量程内,新型时栅原始误差为-32μm~23μm,较现有电磁式时栅位移传感器减小了42.3%.     

温度传感器在微波热疗系统中的应用

由于高频电磁场对温度测量造成的严重干扰，在微波场下的温度测量一直是测量与控制领域难以解决的一个技术难题，文章给出使用热敏电阻－高阻导线组成抗电磁干扰的温度传感器结构以解决这个难题，并重点介绍它的设计方法，这种传感器已成功地应用于医疗部门的微波热疗机的生产，其抵抗强电磁波干扰的特性令人满意。     

基于电磁感应法的交变磁场测量电路设计

为了测量交变磁场的磁感应强度,设计了基于法拉第电磁感应定律的测量电路.详细阐述了电路工作原理和设计思路,并分析了测量结果.由漆包线绕制的空心传感线圈感测到微弱的感应电动势,然后通过精密运放组成的前置放大电路和精密整流电路,得到有效值电压;经过比较整形电路,得到与感应电动势频率相同的方波信号.最后通过单片机AD采样和频率测量,可计算出交变磁场的磁感应强度.所设计的电路测量的百分误差在5%以内,测量结果准确,稳定性好,有一定的实用价值.