霍尔式位移传感器的温度特性

本文研究了霍尔式位移传感器的温度特性，在理论分析的基础上设计了温度补偿电路和相应的软件补偿程序，使温度误差小于０．１％Ｃ＾－１。误差分析的结果与温度实验相吻合，证明了方法的可行性。     

磁势自平衡回馈补偿式直流传感器特性研究

在磁势自平衡回馈补偿式直流传感器中,检测补偿回路对系统的精度有很大影响。检测回路利用一对铁芯和线圈对一次被测电流和二次平衡电流磁势之差进行检测。根据铁芯近似矩形磁化曲线在分析其磁通变化的基础上,对检测回路进行了理论研究,给出了检测灵敏度的计算表达式。通过分析表达式,认为通过增大激励电压和总电流,提高取样电阻,增加铁芯材料相对磁导率、检测绕组匝数,增大铁芯截面积,减小平均等效磁路长度可以提高检测灵敏度,这些措施在实验中得到了验证,灵敏度最高达到了124mV／AT。根据磁势自平衡回馈补偿式直流传感机理,设计了实验样机,实验结果证明了这种新理论的正确性。     

基于ASIC芯片的微小电容测量电路研究

基于一款专用集成电路芯片（ASIC）HTl33实现了一种微小电容测量电路。该电路具有高分辨率、高抗干扰性、偏置调节能力和模拟、数字信号两种输出模式等特点。文中详细论述了测量电路的实现以及电路的抗干扰措施,并通过测定一组微小电容验证了电路的性能。实验表明,电路分辨率达0．5fF,非线性度8．67％。该电路在各种电容式传感器特别是微机电系统（MEMS）传感器中有广泛的应用前景。     

基于电容检测MEMS磁传感器的设计与制作

为实现微型化、低功耗、低成本和高灵敏度的磁传感器,提出了一种基于微型磁扭摆结构的磁传感器,并利用对角度变化非常敏感的差分电容检测技术对磁扭摆的扭转角度进行检测．设计的磁传感器包括微扭摆结构、磁性敏感薄膜和差分检测电容等部分．分析了器件的磁敏感原理和电容检测原理,给出了器件的结构参数和综合设计考虑．利用体硅加工工艺成功制作出了磁传感器样品,并进行了实验测试．测试结果表明磁传感器有良好的线性度和重复性,其磁场检测的电容灵敏度可达到0．2fF／Gauss．根据对磁传感器的热噪声分析,可得到磁传感器最小可分辨的磁场为6．72μT．该磁传感器结构简凑、工艺简单,无需电流激励,大大降低了磁传感器功耗．     

差动式电容传感器数字解调技术

在大地测量中,我们对如何检测出地壳微小的变化很感兴趣,利用差动式电容传感器可以检测出这种微弱的信号。本文对差动式电容传感器的输出信号进行数字化解调,介绍了三种解调方法,分别是数字包络解调、数字正交相干解调及基于Goertzel算法的解调。文中给出了各自的原理,并用Matlab对给出的信号进行了仿真比较,结果分析。     

基于Ansoft的同面电容传感器的研究与仿真

阐述了利用同面电容传感器对复合材料进行无损检测的原理,运用AnsoftMaxwell有限元分析软件对不同极板间距和屏蔽电极形式的传感器进行仿真计算,比较分析了不同极板间距的传感器产生的电场强度变化趋势,研究了不同屏蔽电极对传感器检测特性的影响。仿真结果表明:传感器极板间距越大,检测深度越大,检测特性越好;在3种屏蔽电极中,环形屏蔽电极的检测特性最好。     

硅微谐振式压力传感器中的单端口静电激励-电容检测方法研究

采用静电激励-电容检测方式的硅微谐振式压力传感器具有温度稳定性好、灵敏度高、功耗低等优点,但同频耦合干扰是限制电容检测精度的主要因素。采用频域分离法可有效地克服同频耦合干扰带来的影响。在研究基于频域分离法的单端口静电激励/电容检测的基础上,提出了单端口静电激励/电容检测方案。     

囊式空气弹簧刚度特性的非线性有限元法研究

利用非线性有限元方法，研究由多层复合材料组成的空气弹簧的垂向和横向刚度特性，分析大变形的几何非线性、空腔内空气的状态非线性和胶囊与金属裙板形成的接触非线性，得到了空气弹簧刚度非线性特性的精确描述，并讨论了橡胶囊各参数对空气弹簧垂向和横向特性的影响。通过与试验结果比较，证明了该方法确实可行。     

压力式气浮测力传感器静特性研究

为了避免多维力测量过程中的耦合现象,提出了一种气浮测力的方法。研究建立了压力式气浮测力传感器的特性方程,研制了一种压力式气浮测力传感器静特性实验装置,对理论研究的结果进行了实验验证。实验结果表明,气腔内气体绝对压力Pd在0.5~3.5kg/cm²范围时,气浮测力传感器的线性度为0.8%,回程误差为0.02%,重复性误差为0.1%。     

多点感温式液位传感器的研究

液位测量的方法很多,针对传统液位传感器难以实现准确可靠的液位测量,提出了一种多点感温式液位传感器。它是基于发热体在气(汽)体和液体中放热系数差异显著的特点,设计的一种变液位测量为温差测量的传感器。实验表明,研制的多点感温式液位传感器原理正确,结构可行,性能可靠,可承受高温、高压,能够准确地判断出液气(汽)界面,有必要推广到压力容器内应用。     

电容式密度传感器低密度液氢校准实验研究

设计、搭建了一套可调节密度式多点电容式密度传感器校准装置,并进行了电容式密度传感器低密度液氢的校准试验。实现了对液氢在一定低密度范围内(50—70kg/m3)的调节,突破了传统的常压单一密度点校准技术,实现了液氢多密度点的校准,提高了校准结果的可靠性。对电容式密度传感器校准装置各因素引入的不确定度分量进行了评定,分析得到了该装置的不确定度,试验结果表明采用给液氢增压的方式可以对液氢低密度进行准确控制,该调节装置的不确定度满足电容式密度传感器校准设计要求,并且能够对电容式密度传感器在多种低温流体介质中进行较宽密度范围校准。     

基于CPLD的电容式角度传感器测量电路设计

在介绍一种变面积电容原理的非接触式角度传感器的基础上,提出了两种电容式角度传感器的测量方案.鉴于数字方法实现的测量方案性价比更加优越,从而构建了基于CPLD的电容式角度传感器测量电路,借助于复杂可编程逻辑器件完成传感器信号的鉴相、计数等处理.通过电路的试验以及误差分析,得出该测量电路具有精度高、速度快、抗干扰强、稳定性好等特点.     

气象用湿敏电容传感器的稳定性测试与分析

为研究湿敏电容传感器的稳定性特征,利用14支湿敏电容传感器静态测试数据,用误差年漂移量定量表征湿敏电容传感器的稳定性,并对误差年漂移量的变化规律及影响因素进行分析。结果表明,湿敏电容传感器的稳定性受温度、温度和湿度的交互作用以及厂家制造水平的影响,低温时稳定性较差;室温时稳定性随湿度升高而降低。经过一年的使用,78.6%的湿敏电容传感器无法满足技术指标要求。     

Improved sensing characteristics of dual-gate transistor sensor using silicon nanowire arrays defined by nanoimprint lithography

Abstract

This work describes the construction of a sensitive, stable, and label-free sensor based on a dual-gate field-effect transistor (DG FET), in which uniformly distributed and size-controlled silicon nanowire (SiNW) arrays by nanoimprint lithography act as conductor channels. Compared to previous DG FETs with a planar-type silicon channel layer, the constructed SiNW DG FETs exhibited superior electrical properties including a higher capacitive-coupling ratio of 18.0 and a lower off-state leakage current under high-temperature stress. In addition, while the conventional planar single-gate (SG) FET- and planar DG FET-based pH sensors showed the sensitivities of 56.7 mV/pH and 439.3 mV/pH, respectively, the SiNW DG FET-based pH sensors showed not only a higher sensitivity of 984.1 mV/pH, but also a lower drift rate of 0.8% for pH-sensitivity. This demonstrates that the SiNW DG FETs simultaneously achieve high sensitivity and stability, with significant potential for future biosensing applications.     

Recovery characteristics of optical hydrogen sensor using Pd thin film: Behaviour of three-stage hydrogen desorption

The recovery behaviour of optical hydrogen sensor using Pd film has been investigated. The change in reflectance with hydrogen desorption indicated distinctive characteristics with three-stage curve which depended on thickness of the Pd film. Moreover, the distinction became clearer with increasing number of absorption-desorption cycles. These behaviours were related to the change in pressure concentration isotherm.     

The use of time division of the channels in capacitive and inductive sensor measuring circuits

The principle of time division of the channels when converting the ratio of passive quantities into an active quantity is proposed. Using this principle, methods are developed which enable errors due to the non-ideal nature of the existing conversion of an amplifier and the parameters of the connecting cable to be eliminated. __________ Translated from Izmeritel’naya Tekhnika, No. 7, pp. 40–43, July, 2007.     

Influence of dopant in the synthesis, characteristics and ammonia sensing behavior of processable polyaniline

Polyaniline (PANI) was synthesized by oxidative polymerization of aniline as well as aniline hydrochloride by ammonium persulfate in the presence of para-toluene sulfonic acid (PTSA). This helped in direct usage of the conducting PANI solution for film casting and use as a device for ammonia gas sensing. Viscosity change with applied shear rate was measured for both the polymers. Solid PANI powder was isolated from its tetrahydrofuran solution by using methanol as non-solvent. Thermogravimetric analysis investigated the thermal properties of the solid PANI salts. Elemental analysis of both PANI synthesized in presence of PTSA and PANI synthesized in presence of HCl and PTSA was investigated. A thin coherent film of both the conducting PANI were deposited on glass slides precoated with poly vinyl alcohol (PVA) crosslinked with maleic acid (MA) and was directly used in the sensor device. The morphology of the deposited films was analyzed by scanning electron micrograph. The films were further characterized by Attenuated total reflectance Fourier transformed infrared spectroscopy, ultra violet-visible spectroscopy and X-ray diffraction analyses. Finally, both the doped PANI films on MA crosslinked PVA coated glass slides were used to measure the conductivity and ammonia gas-sensing characteristics.     

Simultaneous sensing of the strain and points of failure in composite beams with an embedded fiber optic Michelson sensor

A fiber optic Michelson sensor was embedded in composite beams to sense the internal strain and points of failure of the composite structures. The bending deformation and matrix cracking were investigated by four-point bending tests of cross-ply composite beams with the embedded fiber optic sensor. The failure points of composite beams were detected by using both a PZT sensor and a fiber optic sensor in order to investigate the fiber optic failure signals. The failure due to matrix cracks in a composite beam was confirmed by the edge replica method. The digital processing of the fiber optic signal was carried out to determine the strains and failure points of composite beams. The failure points were observed from the processed failure signal by high-pass filtering. The initial failure strain of the composite beam was measured and processed from the fiber optic strain signal after low-pass filtering.     

偏振式电流传感器研究进展与展望

随着材料和技术的不断发展,偏振式光纤电流传感器的性能和精度相比过去有了很大的提升,已经能够初步满足当今的工程实际需求。回顾偏振式光纤电流传感器的发展,关键的技术逐步被突破,如温度补偿、线性双折射的抑制、变旋转率光纤、集成光波导技术以及旋转高双折射光纤的制作。基于这些新技术,一种新的偏振式电流传感器被提出。该传感器采用单模光纤进行引导,具有结构简单、精度高、成本低的优点。