微机械谐振式硅桥传感器

本文描述了微机械谐振式硅桥传感器的工作原理,硅桥制作过程以及传感器的工作特性。讨论了传感系统的检测灵敏度与光纤头到硅桥表面距离的关系。实验结果表明,激励硅桥谐振的光功率是在10～450μW,探测信号的光功率在300μW时,其系统的信噪比为25～40dβ,它具有重要的实际应用价值。     

灵敏度可调型光纤FBG倾角传感器研究

提出了一种基于等截面梁弯曲变形原理的灵敏度可调型光纤布拉格光栅(FBG)倾角传感器,通过FBG光栅感受因结构倾角改变而引起的等截面梁弯曲变形,进而实现对结构倾斜角度的测量,并构建了灵敏度可调型光纤FBG光栅倾角检测系统。实验结果表明,该FBG倾角传感器测量范围为±35°,最高灵敏度达到56.93pm/(°),测量精度为0.02°。该传感器可通过改变等截面梁的宽度还可实现对倾角检测灵敏度的有效调节。     

基于通信光缆的光纤油气管线预警系统

提出了一种以光纤分布式扰动传感器为核心,通过随油气管线一同敷设的标准通信光缆为传感介质的新型光纤管线预警系统.该系统利用激光干涉的原理对扰动信号进行实时探测,从而实现对挖掘、偷盗和第三方破坏等事件导致的扰动的实时监测和定位,从而达到管线安全预警的功能.该预警系统成功研制后分别在津唐输油处石油管线和杭州至嘉兴天然气管线进行了多次外场测试,该系统能在长达60 km的管线上实现250 m的定位精度,具有很好的定位稳定性.其测试结果表明:与传统油气管线监测手段相比,该系统具有无需外场供电、本质安全、灵敏度高,监测距离长、可定位以及可预警监测等技术优势,是未来油气管线监测的发展趋势.     

半导体光纤温度传感器特性研究

设计了一种新颖的半导体光纤温度的传感器。通过实验的方法研究了采用不同光源时传感器的输出特性。根据实验数据了分析了传感器的灵敏度、测量范围、线性度和重复性与光源光谱性之间的关系。实验结果表明用该光纤温度传感系统可以实现对温度的非接触稳定测量。     

液体光声效应及光纤水声探测技术的研究

利用液体的光声效应可以实现对液体成分含量的检测.将光纤水声探测技术与液体的声光效应相结合,是一项新的研究内容.本文介绍了液体光声效应产生的三种主要的机制,论述了液体光声效应的研究现状和在科研和生产中的应用.分析了光纤水声传感器用于光声效应中声信号检测的可行性.对各种光纤水听器的结构和原理进行了详细的介绍,对不同类型的光纤水声探测技术进行了讨论和比较,并预测了光纤水听器的发展前景.     

基于概率模型的光纤光栅传感网络优化布置

光纤光栅传感器相比与传统传感器,其特有的轴向敏感性决定了它的探测距离在传感器的不同方向上是有差异的,因此光纤光栅传感器的布置角度对于传感器网络的性能具有很大的影响。基于传统传感器的概率探测模型,本文提出了一种贴合光纤布拉格光栅传感器实际特点的探测模型,并通过实验验证了其正确性,继而利用这一模型,采用粒子群优化算法进行了光纤光栅传感网络的优化布置。最后,同不考虑布置角度的优化布置方法进行了比较,结果表明,在实际应用中考虑布置角度对于传感网络性能具有很大的提升。     

基于R2868型传感器的紫外火焰探测器设计

针对现有火焰探测器响应时间长、探测灵敏度低、探测距离短等问题,本文设计了基于R2868型传感器的火灾监测用紫外火焰探测器.采用具有光能量汇聚功能的光学前窗结构,增大了探测器光学窗口.通过脉冲信号调理电路对传感器输出的脉冲信号进行整形,利用窗口识别算法有效判别火焰状态,可及时响应声光报警.为了满足不同工作条件需求,探测器设有3档灵敏度开关.经试验验证,该火焰探测器能够滤除环境干扰,探测灵敏度高,有效探测距离可达27 m,报警时间小于2 s,具有良好的环境适应性和可靠性.     

TFBG的Fabry-Perot干涉型纵向微位移传感研究

提出了一种利用光纤Fabry-Perot(F-P)干涉结构的微位移传感器,该F-P干涉结构是由双倾斜光纤光栅(tilted fiber Bragg grating,TFBG)沿轴向错开一定距离构成空气腔形成的.入射光经双TFBG及其高反射端面往返传播,从而构成F-P干涉结构.光纤沿纵(z轴)向移动时,F-P腔的腔长发生变化,致使干涉光谱的自由光谱范围随之产生变化.实验验证,该传感器在0~115μm的测量范围内获得了高达0.475nm/μm的灵敏度,较之前提出的光纤光栅型传感器灵敏度提高了近3倍.     

一种高灵敏度光声光纤SO2气体传感器的研究

基于气体光声效应原理，研究了一种高灵敏度光纤SO2气体浓度传感器。用染料激光器作为激励源，激励出光声信号，采用光纤位移传感器测量光声信号。设计了光学长程装置以提高光声腔的灵敏度。用此装置测量SO2气体浓度，给出了实验数据并对结果作了分析。     

微纳Taper光纤干涉传感器的折射率测量理论研究

利用微纳taper光纤干涉方程和微纳光纤传输模式函数关系,建立了微纳taper光纤干涉波长随环境折射率变化的数学模型,指出微纳taper光纤干涉波长的响应规律由基模高阶模有效折射率差、色散因子和环境折射率3个因素所决定.详细研究了微纳taper光纤传感器的灵敏度变化规律,结果表明,传感器的灵敏度随光纤半径变小而急速增大,并随环境折射率的增大而非线性增加,而且探测波长越长,其灵敏度越大.     

Study of a fiber optic humidity sensor based on agarose gel

An optical fiber humidity sensor was fabricated using a hydrophilic gel (agarose) deposited on the tapered plastic optical fiber (POF). The sensing element, agarose, can absorb and exude moisture from/to the ambience, thereby altering its refractive index and changing its ability to modulate the intensity of light that propagates through the fiber. Thus, the operating principle of the sensor is based on the intensity modulation technique, which utilizes a tapered POF probe coated with agarose that is sensitive to humidity. The POF, which was fabricated using an etching method, has a waist diameter of 0.45 mm and tapering length of 10 mm. As the relative humidity varies from 50% to 80%, the output voltage of the sensor with agarose gel of 0.5% weight content decreases linearly from 2.24 mV to 1.55 mV. The agarose-based sensor produces a sensitivity of 0.0228 mV/%, with a slope linearity of more than 98.36%. The tapered fiber with agarose gel of 1% weight content produces a sensitivity of 0.0103 mV/% with a slope linearity of more than 94.95% and a limit of detection of 2.635%, while the tapered fiber with agarose gel of 1.5% weight content produces a sensitivity of 0.0079 mV/% with a slope linearity of more than 98.53% and a limit of detection of 6.853%. The fiber with agarose gel of 0.5% weight content shows higher sensitivity compared to that of 1% and 1.5% due to the effect of pore size, which changes with concentration. The results demonstrate that agarose-based optical fiber sensors are both sensitive and efficient for economical and flexible measurements of humidity.     

反射式强度型光纤传感器在微小位移精密测量中的应用

简要介绍反射式强度型光纤传感器的工作原理及各组成部分的作用。选择合适的光源、光纤对、检测器，对反射率不同的被测物进行位移测量，通过分析数据可以得到相应的位移测量参数；并分析了发送光纤与接收光纤轴间距对输出的影响。在实际测量中，可参照分析结果，根据被测物的情况选取合适的测量点。     

原油含水率检测线圈传感器的优化

为了提高电磁电导法管外测量原油含水率线圈传感器的灵敏度,对影响灵敏度的关键参数--线圈传 感器的距离进行了优化设计。在保持最优频率和电流强度不变的情况下,首先,使用ANSYS进行电磁仿真,通过比较发射线圈和屏蔽线圈在管道内部产生的磁场强度大小确定了两线圈之间的最优距离为0.6 m;然后,利用 MATLAB从0. 1 m到1 m对接收线圈上的电压进行了数据计算,结果表明0. 6 m处的电压值最大,最优距离使原油 含水率的有用信号从0.1 m或1 m的0.03 μV提高到了0.6m的1.27 μV,使传感器的灵敏度提高了41倍;最后, 实际测试了两线圈距离从0.1 m至1 m接收线圈上多点电压值,实验结果表明0. 6 m处的电压值最大,进一步证明了 0. 6 m为两个线圈间的最优距离。     

微悬臂梁传感器工作模式理论分析研究

简要地介绍了微悬臂梁传感器的工作原理和主要特性,着重介绍了微悬臂梁传感器动、静态工作模式下的理论分析方法和提高灵敏度的主要方法。微悬臂梁传感器在动态工作模式下灵敏度极高,但在液态环境下使用易受到液体阻尼效应的影响,只适于在空气中运行使用;相对于动态模式,静态模式受液体黏性的影响较小,更适于在液态中使用。     

Frequency analysis of a wavefront curvature sensor: selection of propagation distance

The linear condition, spatial resolution and filter model of a curvature sensor are obtained by a brief and intelligible frequency analysis approach. The bounded interval of propagation distance is given by considering the linear condition and the noise in intensity measurement. The effects of nonlinearity and measurement noise on different frequency aberrations are discussed. We provide a guide to choose the propagation distance of a curvature sensor. The propagation distance should be large for low-frequency aberrations, which are greatly affected by the measurement noise, and small for high-frequency aberrations, which are greatly limited by the nonlinear effect. For a wavefront composed of various frequencies, it is important to select a proper propagation distance for less nonlinear effects and better noise suppression.     

PDC-SiBCN陶瓷基无线无源温度传感器的性能EI北大核心CSCD

以耐高温聚合物先驱体陶瓷(PDC-SiBCN)为温敏介质材料,金属铂作为谐振腔材料,并在陶瓷表面开槽形成共面天线,制备出集开槽天线与谐振器一体的无线无源温度传感器,实现温度信息的无线无源传输。结果表明:传感器的谐振频率随测试温度的升高呈单调递减变化,PDC-SiBCN陶瓷的介电常数随温度的升高而单调增加,其中热解温度为1000℃的传感器测试温度达1100℃,具有优异的耐高温性和介温特性。同一测试温度下传感器的谐振频率随直径的增大而减小,也随热解温度的升高而降低。通过对传感器的谐振频率-温度拟合曲线进行一阶偏导得到灵敏度方程,传感器在1100℃的高温下有较高的灵敏度。传感器具有良好的循环稳定性能,在室温下实际无线传输距离达到42 mm,当测试温度为1100℃时传输距离可达8 mm,可应用于高温恶劣环境下航空发动机的温度监控。     

Indium oxide thin film based ammonia gas and ethanol vapour sensor

A sensor for ammonia gas and ethanol vapour has been fabricated using indium oxide thin film as sensing layer and indium tin oxide thin film encapsulated in poly(methyl methacrylate) (PMMA) as a miniature heater. For the fabrication of miniature heater indium tin oxide thin film was grown on special high temperature corning glass substrate by flash evaporation method. Gold was deposited on the film using thermal evaporation technique under high vacuum. The film was then annealed at 700 K for an hour. The thermocouple attached on sensing surface measures the appropriate operating temperature. The thin film gas sensor for ammonia was operated at different concentrations in the temperature range 323–493 K. At 473 K the sensitivity of the sensor was found to be saturate. The detrimental effect of humidity on ammonia sensing is removed by intermittent periodic heating of the sensor at the two temperatures 323K and 448 K, respectively. The indium oxide ethanol vapour sensor operated at fixed concentration of 400 ppm in the temperature range 293–393 K. Above 373 K, the sensor conductance was found to be saturate. With various thicknesses from 150–300 nm of indium oxide sensor there was no variation in the sensitivity measurements of ethanol vapour. The block diagram of circuits for detecting the ammonia gas and ethanol vapour has been included in this paper.     

光子晶体光纤F-P干涉式高温传感器研究

本文提出一种用于高温测量的光子晶体光纤F-P干涉传感器,通过熔接机放电使无截止单模光子晶体光纤(ESM-PCF)一个端面完全塌陷,然后再将其与单模光纤(SMF-28e)熔接起来,最后按照设计长度切断ESM-PCF。由于在熔接点处ESM-PCF完全塌陷使其模场直径扩大,减小了与SMF-28e的模场失配损耗,并提高了熔接面的反射光强。这种方式制作简单,相对于以往的光子晶体光纤F-P干涉传感器具有更高的干涉光强度。实验结果表明,该传感器测量温度可达1100℃,温度灵敏度为29.4nm/℃,可以预见这种结构稳定、线性度好的全光纤传感器在机械、航空、冶金领域等具有一定的潜在应用价值。     

Gas sensing properties of lead doped tin oxide thick films

The present investigation deals with the fabrication of liquid petroleum gas (LPG) sensor materials based on semiconducting oxide SnO₂. The gas sensor materials have been prepared by conventional solid-state route. The effect of Pb incorporation, operating temperature, morphology, and sensitivity is discussed using the results of X-ray diffraction (XRD), along with sensing performance. Out of various sensor compositions, Pb doped SnO₂ sintered at 1000 °C for 2 h has shown high sensitivity towards LPG at an operating temperature of 150 °C. Different characterization techniques have been employed, such as surface area analyzer, X-ray diffraction (XRD), to study the formation of SnO₂, surface area and crystallite size, respectively. The results suggested the possibility of utilizing the sensor element for the detection of LPG.     

Optimizing loss of the dielectric stack for Bloch-surface-wave sensors under different interrogation schemes

For enhancing the sensitivity of the Bloch surface wave-based sensing applications, the dependency of the Bloch surface wave (BSW) resonance dip and the associated phase change on the loss of a truncated one-dimensional photonic crystal structure is numerically analyzed and studied. Furthermore, through evaluating the sensitivity of a BSW sensor based on the intensity interrogation scheme and the phase detection method, a comparison is carried out to optimize the sensing performance. The results demonstrate that the sensing sensitivity of the BSW sensor is significantly affected by the applied sensing schemes. It is shown that the optimized device loss is not the same for different sensing schemes. Relatively high phase-detection sensing sensitivity can be maintained for low-loss BSW devices, while that of the intensity interrogation scheme may drop sharply. On the other hand, the performance of intensity interrogation scheme is less affected by the higher device loss. Our result could be useful for improving the performance of the BSW sensors and selecting the appropriate sensing scheme for such devices.