Effects of rapid thermal annealing on surface acoustic wave ultraviolet sensors using ZnO nanorods grown on AlN/Si structures

In this study, we demonstrate a high sensitivity of surface acoustic wave (SAW) ultraviolet (UV) sensor based on ZnO nanorods (NRs) grown on an aluminum nitride (AlN)/silicon (Si) layered structure. The one-dimensional ZnO NRs act as a high-UV sensing material due to their large surface-to-volume ratio. The fabrication of SAW UV sensor is entirely compatible with micro/nano electromechanical (M/NEMS) process with conventional lithography and synthesized ZnO NRs by hydrothermal method at low temperature. The rapid thermal annealing (RTA) process effectively improved the optical properties of ZnO NRs and the sensitivity of the SAW UV sensors. The resulting SAW UV sensors responded to various UV light intensities, and the RTA-processed samples showed high sensitivity. The SAW UV sensor after RTA treatment at 600 °C showed the highest sensitivity with a 130 kHz frequency shift at a UV light intensity of at 0.6 mW/cm², a 5-fold increase in sensitivity compare with as-grown sample.     

Application of TiO<Subscript>2</Subscript> thin film with nanorods to surface acoustic wave type ultraviolet photo detection

TiO₂ thin films with nanorods grown on 128° Y?cut LiNbO₃ and 90° rotated 42°45′ ST?cut quartz were used to fabricate surface acoustic wave ultraviolet photodetectors. TiO₂ thin film was deposited by radio?frequency magnetron sputtering and TiO₂ nanorods were then synthesized on the thin film via the hydrothermal method. 128° Y?cut LiNbO₃ is a Rayleigh wave substrate with a high electromechanical coupling coefficient, whereas 90° rotated 42°45′ ST?cut quartz is a surface skimming bulk wave substrate with a high wave velocity. The effects of substrate characteristics and TiO₂ nanorod morphology on the ultraviolet sensitivity of the surface acoustic wave photodetectors were investigated. The variations of insertion loss, phase, resistance, and capacitance under ultraviolet illumination were examined. The performance of the TiO₂ thin film with nanorods deposited on 128° Y?cut LiNbO₃ is much greater than that of the film deposited on 90° rotated 42°45′ ST?cut quartz, which can be attributed to the former’s high electromechanical coupling coefficient.     

声表面波无源无线温度传感器产品研究进展

声表面波（SAW）温度传感器可以实现无线无源检测,满足高温、高压、强电磁辐射和强电磁干扰等恶劣环境下正常工作,属于高水平传感器。首先介绍了应用SAW技术的无源无线温度传感器谐振型和延迟线型2种结构的基本工作原理,着重描述了目前国内外高温和低温SAW无源无线温度传感器的产品性能,对各产品进行了比较和分析,提出了SAW温度传感器询问距离的优化方法。询问距离的优化研究对SAW温度传感器在更广泛领域的应用将有深远意义。     

基于声传感器阵的舰船被动定向研究

在被动声探测设备中声传感器阵对舰船目标宽带噪声源的精确定向取决于时延估计的精度,针对这一问题,将自适应参量模型算法与变步长的 LMS算法相结合,提出了一种可高精度估计任意时延,且收敛速度快的时延估计算法.结合舰船辐射宽带噪声,以正四面体声传感器定向阵列为例进行了计算机仿真,仿真结果表明：该方法估计所得的方位角误差小于0.1°,俯仰角误差小于1°,实现了对舰船目标宽带噪声源的精确定向,具有很好的工程实用价值.     

Ni-Cr合金超声导波温度传感器的设计

为了实现在高温环境下对温度的精准测量,基于超声导波测温原理,设计了一种镍铬合金超声导波温度传感器。镍铬合金具有抗氧化性好、高温环境下强度高、热膨胀系数小、导热性能好以及长期使用不变形等优点。经过分析,选用长为1 m,直径为0.8 mm,区截长度为30 mm的Ni-Cr合金丝作为敏感元,采集超声回波信号,利用互相关计算渡越时间,实现对温度的测量,并对传感器的测温范围、灵敏度以及重复性进行了分析,实验结果表明该传感器在1 100℃的强氧化环境下准确度达到了1%。     

Bulk acoustic wave RF technology

RF filtering in mobile terminals is dominated by surface acoustic wave (SAW) and bulk acoustic wave (BAW) based filters due to their high performance, small size, and low cost. As compared to SAW filter technology, BAW filter solutions can provide lower insertion loss, better selectivity, higher power handling, higher operation frequency, and better ESD protection. With these advantages, BAW filter technology has been gaining more market share in wireless communication application.     

无线传感网络在冲击波场中的应用

主要介绍了无线ZigBee传感网络的星型结构（一个主节点和多个从节点）在冲击波测试技术中的应用,利用无线传感网络触发的同步性使冲击波电路几乎同时进入工作状态并且通过单片机MSP430控制电路实时传回具体位,置的测试数据。     

基于LFMCW的L_(CR)波切向正应力检测方法的研究

以LFMCW（linear frequency modulated continuous wave）时间间隔测量原理为基础,针对LCR波（the critically refracted longitudinal wave）声弹性应力检测脉冲激发方式时存在的问题,提出了一种基于LFMCW方式激发LCR波的切向正应力检测系统,使用新的检测方法通过发射信号和接收信号形成的拍频信号来反映波的传播时间,用抛物线插值与最小二乘相结合的数字测频方法准确测量拍频频率。实验结果证明了该系统对LCR波传播声时检测的有效性。     

High frequency response of Bragg reflector type film bulk acoustic wave resonator

Abstract

We fabricated a Bragg reflector type FBAR using AlN piezoelectric with quarter wavelength thickness, where the Bragg reflector was composed of W-SiO₂ pairs. By numerical simulation considering actual acoustic losses of each layer, we analyzed the frequency response of the resonator and could explain it using an equivalent circuit with parasitic elements. The Effective electromechanical coupling constant (K ² _eff ) and the Quality factor (Q_s ), figures of merit of the resonator, were about 1.1% and 307, respectively.</ab>     

基于磁阻传感器的非接触式位移测量

针对塔机起重力矩监控器中高精度、非接触式的位移测量要求,选用Honeywell公司的磁阻传感器HMC1501实现了位移的精确测量。该磁阻传感器具有体积小,精度高,抗干扰能力强,可以实现非接触式测量的优点。并利用BP神经网络对磁阻传感器进行非线性补偿,提高了系统的测量精度、可靠性,而且降低了成本。     

Surface acoustic wave sensors to detect volatile gases by measuring output phase shift

This paper presents properties of saw acoustic wave (SAW) gas sensors to detect volatile gases such as acetone, methanol, and ethanol by measuring phase shift. A dual-delay-line saw sensors with a center frequency of 100 MHz were fabricated on 128^∘ Y-Z LiNbO₃ piezoelectric substrate. In order to improve sensitivity of SAW sensors, a thin titanium (Ti) film as mass sensitive layer was deposited using e-beam evaporation on the surface of the SAW sensors. In our investigation the response time and sensitivity of SAW sensors were measured. The response time and sensitivity of SAW sensor with thin Ti film were strongly improved because of changing electrical and mechanical properties in the mass sensitive layer. As a result, high sensitivity and fast response time could be achieved by deposition of thin Ti film as mass sensitive layer on the surface of SAW sensor. It can be applied for high performance electronic nose system by assembling an array of different sensors.     

基于LabVIEW的SPR传感检测系统的设计

SPR传感器已经成为检测、分析生物分子相互作用的有效工具。为满足快速高通量检测的需要,高通量SPR检测仪器已经成为SPR检测仪器的重要发展趋势。研制出一套高通量的SPR成像检测系统,以LabVIEW为开发工具,设计出一套实用的实时控制与数据采集分析程序。主要讨论了高通量、快速的SPR检测系统的设计,以及基于LabVIEW的实时过程控制与图像采集分析系统软件的设计与实现,运用该检测系统,可以实现快速的SPR检测,满足高通量、高精度的检测要求。     

基于零磁通原理的小电流传感器设计

为满足电力系统绝缘在线监测需求,设计制作了一种基于零磁通原理的精密小电流传感器.该传感器通过重新设计传感器结构,进行硬件"零磁通"补偿,同时用动态平衡电子电路对其进行动态补偿,达到近似"零磁通"的效果.实际测试表明:该小电流传感器具有高精度(角差、比差分别在1.5'、千分之一以内)、高稳定度、调整性好,抗干扰能力强的优...     

A basic study on the dynamic water level limit sensor utilizing acoustic impedance matching

In this study, an ultrasonic level limit sensor with a new structure utilizing the acoustic impedance matching is proposed in order to check the change of water-level. Two PZT resonators with the same property are bonded directly on a polyethylene plate. The first one is for transmitter as an ultrasonic transducer and the other is for a receiver. In this case, a polyethylene plate will operate as an acoustic guider to propagate a transverse wave between the two PZT resonators in air. On the other hand, a polyethylene plate having similar acoustic impedance with the water will be emitting an acoustic energy into the water as a longitudinal wave in the water. According to this mechanism, there was large difference of acoustic output signal between underwater and air. Therefore, it is believed that this proposed level limit sensor could be used as a new dynamic one, toughened from the external mechanical noise.     

舰炮对空脱靶量测量声传感器阵设计

对空脱靶量测试是舰炮武器系统试验的核心内容之一.在声学测量原理基础上,提出采用声学测量方案,利用声传感器阵来实现对空脱靶量测量任务.根据声学传感器的测试任务和固有的特点,确定传感器设计思想,选用适合的声学传感器,并建立了合理适用的传感器阵物理模型.利用空间传感器阵的多点测量方法,成功完成舰炮武器系统对空脱靶量的测量,并通过试验验证了其正确性、可行性.     

Surface modification of III-V compound semiconductors using surfaceelectromagnetic wave etching induced by ultraviolet lasers

The surface modification of semiconductors by laser-induced surface electromagnetic wave (SEW) etching was investigated. With the novel etching method using a holographic exposure system, submicron periodic dot structures were fabricated directly on semiconductor substrates (n-InP, n-GaAs, and InGaAs-InP). Making use of laser polarization dependence in this etching system, a variety of surface modifications could be achieved on the semiconductors. In particular, in the case of using the s-polarization light, periodic submicron dot structures with a geometrical diameter down to 80 nm could be obtained directly using a single-step process without a mask. The InGaAs-InP dot structures were studied optically by means of photoluminescence spectroscopy, and the blue shift of the photoluminescence energy up to 5.36 meV was observed for the smallest dots, which displayed a lateral quantization     

基于FPGA的波形发生器设计

利用Altera公司的EP2C8Q208为控制核心,以TLV5618为DA转换芯片,运用DDS基本原理,通过Quartus II和ModelSim软件编写波形发生器的每个单元模块和测试模块,利用数码管显示波形的种类和频率值,利用按键步进控制波形的频率大小,系统产生的8种波形包括4种常规波形、3种常见调制波形以及任意波形。实验表明,采用该设计系统稳定性高,可扩展性强,波形可以任意调整,降低了设计的成本。     

压电复合传感器阵列用于导波管道检测研究

利用压电复合传感器阵列对管道进行了超声导波检测实验。采用2种频率和2种周期对拥有不同缺陷数的管道进行了对比实验。实验结果表明MFC阵列可以很好的用于管道缺陷检测,在70kHz和130kHz时信号的信噪比较高,激励信号可以采用5或10周期的汉宁窗调制的正弦波信号,当沿周向的缺陷逐渐增大时,缺陷回波基本呈线性逐渐增大,端面回波则逐渐减小。     

基于ZigBee技术的无线脉搏传感网

ZigBee技术以其低功耗、高性能的特点在无线传感器网络的开发上有着广泛的应用和广阔的开发前景.使用HK-2000B+脉搏传感器采集人体脉搏信号,以TI公司的CC2530为开发平台,信号经模数转换,无线传输和数据处理,构建一个实时的脉搏传感网络.同传统的监测系统相比,该系统具备无线传输、高稳定性、低功耗、低成本的优点,充分发挥了ZigBee技术在组建无线传感网络上的优点,对可穿戴式设备、远程人体生理信号监护系统,运动员专业训练系统等开发具有重要的借鉴意义.