A Novel Humidity-Sensitive Material Based on PDEB with Nickel Complex Catalyst

lntr0ducti0nHumidityisaveryimportantphysicalpr0perty,andinrecentyears,theresearch0nhu-miditysensors,whichfocused0nl0okingforproperhumidity-sensitivematerials,hasattractedmoreandmoreattentionw0rldwide.l~2PDEBisahydrophobicpoIymerwithhighrr-c0njugatedstructure,whichpresentsitwithpotentialapplicationinelectr0nics.'~'Inourrecentstudy,itwasfoundtobesensi-tivetohumiditychange,whichmakesitap0tentialhumidity-sensitivematerialf0rhu-miditysensors.However,acc0rdingt0literatures,PDEBpreparedisinsoluble…     

电子鼻测定植物挥发性有机物方法研究

建立了电子鼻技术(GC/SAW)快速实时检测植物挥发性有机物(BVOCS)的分析方法。考察了检测器温度、进样温度、柱温、升温速率等因素的影响,确定了电子鼻技术分析BVOCS的最佳条件为:检测器温度60℃、进样口温度100℃、柱温40～145℃(10℃/s)、阀温145℃、预浓缩管250℃、载气流速3mL/min。在上述条件下,测得不同时间(日内、日间)α-蒎烯和异戊二烯分别在0.027～8.580mg·L-1、0.425～68.100mg·L-1范围内线性良好;α-蒎烯和异戊二烯的回收率分别在90.74%～107.41%和91.29%～102.88%之间;相对标准偏差(RSD)均小于5%;检测限在0.2～1.0μg·L-1内。     

Fabrication and characteristics of a surface acoustic wave UV sensor based on ZnO thin films grown on a polycrystalline 3C-SiC buffer layer

Zinc oxide (ZnO) thin films were deposited onto a polycrystalline (poly) 3C-SiC buffer layer for surface acoustic wave (SAW) ultraviolet (UV) sensing using a magnetron sputtering system. X-ray diffraction (XRD) and photoluminescence (PL) spectra showed that the ZnO film grown on 3C-SiC/Si had a dominant c-axis orientation, a lower residual stress, and higher intensity of luminescence at 380 nm of ZnO thin film. The SAW resonator UV detector were fabricated on ZnO/Si structures with a 3C-SiC buffer layer. The SAW resonator exposed under UV illumination had a linear response with sensitivity of 85 Hz/(μW/cm²) in ZnO/3C-SiC/Si structures, as compared to 25 Hz/(μW/cm²) in ZnO/Si structures with UV intensity varied until 600 μW/cm².     

Differentiation of red wines using an electronic nose based on surface acoustic wave devices

An electronic nose, utilizing the principle of surface acoustic waves (SAW), was used to differentiate among different wines of the same variety of grapes which come from the same cellar. The electronic nose is based on eight surface acoustic wave sensors, one is a reference sensor and the others are coated by different polymers by spray coating technique. Data analysis was performed by two pattern recognition methods; principal component analysis (PCA) and probabilistic neuronal network (PNN). The results showed that electronic nose was able to identify the tested wines.     

Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer

The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.     

Laser generation of surface acoustic modes guided by copper lines of sub-micron width on silicon

Surface acoustic waves guided by a copper line embedded in a silica film on a silicon wafer were generated and detected optically using the laser-induced transient grating technique. Lines as narrow as ∼0.2 μm yield a good signal despite the much larger size of the laser spot. The phase velocity of the guided mode is slightly lower than the surface acoustic wave velocity in the thin film structure. Good correlation between the acoustic frequency and the electrical resistivity of the copper lines results from the dependence of both measurements on the line width.     

高温度稳定性声表面波信道化滤波器组研制

本文报道了作者研制的频率范围分别为200—350MHZ和350一500MHZ的两种15信道声表面波滤波器组的结果。为了克服现有技术温度稳定性较差的缺点，基片材料采用Yll2°LiTaO3，温度稳定性比现有技术提高3．5—5倍。每个滤波器中的两个叉指换能器一个采用特殊抽样的单指换能器，另一个采用三次谐波工作的分裂指换能器，从而避免了采用基频工作的分裂指换能器所需的0．8μm。工艺。输入匹配网络采用改进的串并联匹配网络，降低了输人匹配网络的插人损耗，补偿了因采用Yll2°LITaO3，单个滤波器插损较大的缺陷，使滤波器组总的插入损耗与现有采用YZ或Y128°LiNbO3的滤波器组相当。     

Integrated Acousto-Optical Temperature Sensor

In this work, we investigate the performance of a novel integrated acousto-optical temperature sensor fabricated in LiNbO₃ and operating with ultrashort light pulses (2 ps). Five parameters (time duration, bandwidth, time intensity maximum, frequency intensity maximum, and output energy on the output pulse converted for the TM mode, as a function of temperature) were observed for the switched pulse at the output of the sensor (TM mode) with and without the presence of an increasing linear self-phase modulation (SPM) profile. Comparing all analyzed parameters, one can conclude that the pulse intensity is presenting the larger variation (100.09%) as a function of the temperature change (24.5 to 400°C) in a configuration without profile. Considering the increasing linear SPM profile, all the analyzed parameters are presenting a significant increase in the percentile variations in the studied range of temperature (24.5 to 400°C). Comparing all the five parameters, in two configurations (with and without the use of linear SPM profile), one can conclude that the time intensity maximum showed to be the most suitable parameter as measurement to be accomplished in a schematic detection for the temperature sensing in the range 24.5 to 400°C. We can conclude that the sensitivity of the AOTS is improving in the configuration with the increasing nonlinearity profile (β = 2) and for higher temperature.     

新型表面波电流传感器优化设计

本文对结合磁致伸缩效应的新型声表面波电流传感器进行优化设计。传感器采用80 MHz声表面波双通道延迟线型差分振荡器,并在传感通道SAW器件表面声传播路径上溅射磁致伸缩薄膜,利用薄膜材料在电流激发磁场作用产生的磁致伸缩效应引起声传播速度的变化,并以相应振荡器频率的变化来表征待测电流。通过对不同磁致伸缩材料(FeCo和FeNi)以及薄膜厚度的传感效应进行分析,用以为传感器的优化设计提供思路,并通过实验进行验证,实验结果显示,相对于FeCo而言,采用FeNi作为敏感材料的电流传感器具有良好的重现性、线性度以及较高的灵敏度。     

Design of high frequency piezoelectric resonators utilizing laterally propagating fast modes in thin aluminum nitride (AlN) films

Highly c-oriented aluminum nitride (AlN) thin piezoelectric films have been grown by pulsed direct-current (DC) magnetron reactive sputter deposition. The films were deposited at room temperature and had a typical full width half maximum (FWHM) value of the (0 0 2) rocking curve of around 2°. Resonant devices in thin film plates having surface acoustic wave (SAW) based designs were fabricated by means of low resolution photolithography. The devices were designed to operate with the fast Rayleigh and Lamb modes respectively. Both types of devices exhibited propagation velocities in excess of 10 000 m/s and sufficient electromechanical couplings. The device measurements illustrate the big potential of these modes for the development of low cost IC compatible electroacoustic devices in the lower GHz range. The basic properties of the modes studied are discussed in a comparative manner. Potential commercial applications are also outlined.