Temperature sensor using ferrofluid thin film

A brand new design of temperature sensor using ferrofluid thin film is proposed in this paper. When magnetic field parallel to the plane of the ferrofluid thin film is applied, magnetic chains form in the same direction of the magnetic field, which results in the suppressing of optical transmission. It is observed that the optical transmission is changed by the ambient temperature, so that temperature sensor can be constructed by measuring the transmission power of a laser. The physics and the sensitivity of the temperature sensor are also analyzed.     

Development of a novel piezoresistive thin film sensor system based on hydrogenated carbon

Thin film sensor systems based on hydrogenated carbon have the advantage to combine two very important characteristics in order to be used in measurement engineering: Firstly, the sensory layer demonstrates piezoresistive behavior and secondly its good properties related to hardness and wear resistance lead in a tribologically stable system. Therefore, the thin film sensor systems can be applied into the main distribution of force within machine parts or used for universal interchangeable sensor systems, e.g. sensory washers. In this article the deposition of a self-contained thin film sensor system on a large technical component (spindle shaft) is shown. The spindle shaft with a length of 480 mm and an outer diameter of 90 mm is part of a belt driven machining spindle for planing machines in woodworking industries. In order to establish a measurement system, which allows monitoring the clamping force of the tool holder and the imbalance of the mounted tool, the thin film sensor system was directly applied to the front surface of the spindle shaft. For this application a novel self-contained thin film sensor system was developed, which consists of an alumina layer for electrical isolation, a chromium layer to establish internal sensor electrodes, a piezoresistive hydrogenated carbon layer (1 μm) and a second covering wear resistance and insulation layer (silicon and oxygen modified carbon layer). The piezoresistive sensor layer and the top layer are part of the diamond like carbon layer family (Robertson, Diam Relat Mater 12:79–84, 2003; Bewilogua et al. DLC based coatings for tribological applications, pp. 67–75, 2006; Biehl et al. Thin Solid Films 515(3):1171–1175, 2006, Novel measurement and monitoring system for forming processes based on piezoresistive thin film systems. Springer Verlag, pp. 879–883, 2010).     

PPy-CeO2复合薄膜柔性NO2传感器的制备与气敏特性研究

以吡咯(Py)单体为前驱液,六水合三氯化铁(FeCl3·6H2O)为氧化剂,通过化学氧化聚合法与自组装相结合工艺在柔性聚酰亚胺(PI)衬底上制备聚吡咯-二氧化铈(PPy-CeO2)复合薄膜.通过紫外-可见吸收光谱(UV-Vis)、傅立叶红外光谱(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)及X射线衍射(XRD)、X射线电子能谱分析(XPS)对纯PPy和PPy-CeO2复合材料进行了表征分析,结果表明PPy-CeO2呈典型的核-壳结构.在室温条件下研究了纯PPy薄膜和PPy-CeO2复合薄膜对二氧化氮(NO2)的响应特性,结果表明,PPy-CeO2复合薄膜传感器显示出更优的响应特性,灵敏度为纯PPy薄膜传感器的12.6倍,且具有良好的重复性和选择性.最后讨论分析了PPy-CeO2复合薄膜传感器的NO2敏感机理.     

基于三维感应线圈的新型MEMS电流传感器

基于三维感应线圈,研制了一种新型微机电系统(MEMS)电流传感器。传感器以玻璃为衬底,以聚酰亚胺为支撑和绝缘材料,通过溅射、光刻、电镀、抛光等微加工工艺在玻璃衬底上制作出三维感应线圈。传感器具有功耗低、线性度好、质量轻和结构简单等优点,通过U型装置固定在传输导线表面,安装方便。实验测试结果表明:电流传感器两端输出的电压信号与传输线路中的电流成线性关系,线性度为0. 58%。     

基于钳位电路的碳纳米管薄膜声源系统优化

碳纳米管薄膜是一种由碳原子组成的新型纳米材料,可被制作成一种基于热致发声效应的扬声器。针对碳纳米管薄膜电-热-声系统的频率失真问题,提出添加钳位电路的解决方法,并进行了理论研究和实验验证。结果表明,加入钳位电路后,系统输出的声波频率与输入电压频率变为一致,且声能量显著增大,声压级提高约5 d B。与传统叠加直流偏置电压的方法相比,无需直流电源,降低了系统功耗。     

Characterisation of PZT thin film micro-actuators using a silicon micro-force sensor

This paper reports on the measurements of displacement and blocking force of piezoelectric micro-cantilevers. The free displacement was studied using a surface profiler and a laser vibrometer. The experimental data were compared with an analytical model which showed that the PZT thin film has a Young's modulus of 110 GPa and a piezoelectric coefficient d_31,f of 30 pC/N. The blocking force was investigated by means of a micro-machined silicon force sensor based on the silicon piezoresistive effect. The generated force was detected by measuring a change in voltage within a piezoresistors bridge. The sensor was calibrated using a commercial nano-indenter as a force and displacement standard. Application of the method showed that a 700 μm long micro-cantilever showed a maximum displacement of 800 nm and a blocking force of 0.1 mN at an actuation voltage of 5 V, within experimental error of the theoretical predictions based on the known piezoelectric and elastic properties of the PZT film.     

表面等离子共振Ag-SnO_2薄膜光化学气体传感器

提出一种新型的Ag-SnO2复合膜H2S光化学表面等离子共振(SPR)气体传感器结构。结构中使用一只金红石材料作成的棱镜作为耦合棱镜,在棱镜的底边采用射频溅射技术制作Ag-SnO2复合膜(CuO为掺杂质),Ag膜和SnO2膜的厚度分别为50 nm和100 nm,在复合膜上设置待测气体的样品池。在白光入射激励下,复合膜的分界面发生SPR现象。实验结果表明:SPR的波长与H2S气体的体积分数基本呈线性关系。     

基于柔性热膜传感器的流体壁面剪应力测量系统

为实现流体壁面剪应力在线测量,设计了一种基于柔性热膜传感器的流体壁面剪应力测量系统.通过分析柔性热膜传感器作用机理,研发了基于LTZ1000电压基准的高精度恒流驱动电路,开发了基于DSP2812,AD7609的18位真差分同步高速数据采集模块,并通过温度补偿方法对传感器输出信号进行了环境温漂修正.系统性能测试表明:当流场温度在10 ～30℃范围变化时,剪应力测量分辨率在0～10 Pa范围内优于0.2Pa,流体温度变化引起的系统输出信号偏差为0.6％/℃,满足实际流体壁面剪应力测量要求.     

基于MEMS的镍薄膜加热器催化传感器研究

设计了基于微机电系统(MEMS)工艺,以镍薄膜作为加热体的新型催化传感器。通过磁控溅射沉积、刻蚀等工艺制成镍薄膜加热器,并对其进行了稳定化热处理以及防氧化聚合物涂层处理。传感器性能测试结果表明:镍薄膜加热器具有良好的抗高温氧化能力;气氛老化可缩短50%的老化时间;甲烷气体浓度与灵敏度呈良好的线性关系;对甲烷的灵敏度约为30 m V/1%Vol;传感器功耗约为150 m W,零点和灵敏度年漂移小于1. 5%LEL。     

薄膜热电偶温度传感器研究进展

随着低维材料技术的发展和对测温要求的提高,薄膜热电偶温度传感器应运而生,其快速响应特性为测量瞬变温度提供了可能。综述了薄膜热电偶温度传感器国内外发展现状,着重介绍了薄膜临界厚度的确定、扩散现象的影响、制备工艺等关键技术,并对其未来发展做出了展望。     

InSb-In共晶体薄膜磁阻式电流传感器

介绍一种用锑化铟—铟 (InSb -In)共晶体薄膜磁阻元件 (MR)制成的电流传感器 (MRCS) ,并设计了一种能较大幅度增大其输出电压的信号处理电路。当处理电路的电压增益为 80db ,待测的 5 0Hz交流电流在 40～ 110mA之间变化时 ,输出电压在约 1V至约 3 .5V范围内变化 ,并且两者之间有比较好的线性关系 ,标准偏差 <0 .0 2。输出信号电压与本底噪声之比是 (2 4～ 46 ) :1。     

基于柔性涡流传感器疲劳裂纹监测试验研究

结构健康监测对于保证飞行安全具有重要意义,底层涡流传感器是体系获取结构状态的重要组成.设计了柔性涡流传感器,搭建了预置裂纹监测系统,针对304奥氏体不锈钢、2A12-T4铝合金和TC4钛合金三种材料进行了预置裂纹监测试验.试验表明:对于电导率较小的304奥氏体不锈钢和TC4钛合金材料,最优监测频率增大;预置裂纹对涡流传感器跨阻抗幅值和相位影响不同,相对于幅值变化,相位变化较小;预置裂纹宽度增大会使得传感器跨阻抗变化率增大;柔性涡流传感器感应线圈实现了对裂纹长度的识别和定量监测.     

基于PANI/PdO复合薄膜的压电甲烷传感器

研究了一种基于压电原理的甲烷传感器。运用化学氧化聚合法和层层自组装法制备了对甲烷气体敏感的PANI/PdO复合薄膜,通过溅射工艺将薄膜生成在压电材料上,利用敏感薄膜对甲烷的吸附改变晶振频率,从而检测出甲烷气体的含量。实验表明:压电甲烷传感器具有较好的选择性,在0%~2%的甲烷体积分数范围内具有较好的线性输出。     

All-optical hydrogen sensor based on a high alloy content palladium thin film

Optical reflectance measurements were performed to determine the hydrogen response characteristics of 20 nm thick Pd_0.6Au_0.4 films. The response time and signal change characteristics were determined as a function of hydrogen concentrations ranging from 0.05% to 4% in a balance of dry CO₂ free air. The detection limit was determined to be 0.05%, with a corresponding response time of 130 s, while at 4% hydrogen concentrations the response time was 5 s at ambient temperatures. A linear decrease of both the signal change and response time was measured within an operating temperature range between 25 °C and 100 °C for a 1% hydrogen in air gas mixture. The sensor response dependence of the Pd_0.6Au_0.4 film with a change in humidity was determined between ambient levels and 95% relative humidity (RH). While the signal change was independent of humidity the response time increased due to water adsorption on the Pd alloy sensing layer. A similar increase in response time was shown for 100 ppm of background CO mixed with 1% hydrogen in nitrogen at room temperature. At an elevated operating temperature of 80 °C, 100 ppm of CO did not affect the sensor response towards 1% hydrogen in a balance of nitrogen. Reliability tests have been performed over a 1-year time period and the sensing specifications have not drifted beyond 2% and 13% of the calibrated signal change and response time, respectively. A response time on the order of seconds and the proven stability of the high alloy content Pd thin film demonstrate the promising attributes of this material for use in an all-optical hydrogen sensor.     

A differential capacitive thin film hydrogen sensor

A compact, differential, hydrogen-specific sensor based on the lattice expansion of LaAl_0.3Ni_4.7 metal hydride thin films has been fabricated and characterized. Characterization of LaAl_0.3Ni_4.7 films performed using a capacitance dilatometer revealed that the lattice expansion was proportional to the partial pressure of H₂ over the range 0.01–1.3 atm used in this experiment. The films were mechanically robust to cycling between vacuum and partial pressures of H₂ up to 1.3 atm and were not poisoned by exposure to atmosphere's containing up to 24% carbon monoxide. A wafer level process has been established for the fabrication of the differential hydrogen sensor which includes both an active LaAl_0.3Ni_4.7 sensing capacitor and an inert Au reference capacitor. A minimum sensitivity of 400 ppm hydrogen is calculated for the differential device.     

单线圈电流型振弦式传感器

介绍作者研制的一种新型振弦式传感器 :单线圈电流型振弦式传感器 ,它克服了双线圈型与电流型振弦传感器的主要缺点 ,可用短弦、长电缆 ,无倍频干扰 ,有良好应用前景。     

导电聚合物薄膜声表面波传感器敏感特性研究

利用旋涂方法在声表面波(SAW)器件的延迟通道上制备了酞菁铜(CuPC)掺杂的聚乙烯吡咯烷酮(PVP)敏感薄膜,并对制备的薄膜用四探针法和扫描电子显微镜(SEM)进行了测试和表征。结果表明:薄膜中的CuPC颗粒均匀分散在聚合物薄膜中,其粒径尺寸约为20 nm,薄膜的电导率在10-6Ω-1.cm-1量级。根据提出的理论模型,计算出由于敏感膜的质量变化与电导率的变化导致了中心频率的漂移,该漂移值的理论计算结果与实验验证结果相符。     

电容式薄膜真空压力传感器设计

为了满足在工程型号上的使用要求,解决真空压力传感器敏感探头壳体与传感器壳体隔离绝缘问题;传感器输出信号非线性的补偿问题;传感器热零点漂移的全电路的温度补偿问题,采用电容式薄膜封装结构,壳体为电容的另一极,在0.1~100 Pa的范围内进行了校准测试,实现了传感器0.2%FS的测量精度.     

基于偏磁薄膜矫正的直流光学电流传感器设计

针对高压输电中直流的检测,提出一种基于偏磁薄膜矫正的直流光学电流传感器.偏磁薄膜固定磁场在石榴石材料中的方向提高了传感器测量精度,采用偏振计直接检测偏振角的方法消除了偏振面预偏角度误差对测量系统的影响.对传感器实现直流检测进行理论分析,设计了传感器的光路结构,并使用传感器进行直流检测实验.结果表明：该传感器能兼顾灵敏度和测量范围的需要且测量输出线性度高,线性拟合度为0.999 53,多次测量重复性好,误差小于0.4％.