高分子电容湿敏元件失效模式研究

本文针对目前国内湿敏元件普遍存在可靠性问题，选择高分子湿敏元件作为研究对象，对其进行失效分析，指出失效原因、失效规律，并给出失效模式，即相应的ＦＭＥＡ。这对于进行元件的可靠性增长具有现实意义。     

降低高分子电容式湿敏元件湿滞的实验研究

针对高分子电容式湿敏元件的湿滞无法通过后续电路完全实现补偿的问题,提出了从高分子电容式湿敏元件本身降低湿滞的方法。主要从制作工艺、湿敏材料的选择两方面进行了实验验证,并对制作完成的高分子电容式湿敏元件进行性能测试与数据分析。实验结果表明：通过控制制作工艺和对湿敏材料进行改性可以降低湿滞,湿滞优于1.5%RH。采用该方法制作的湿敏元件无需再次通过后续电路进行湿滞补偿。     

新型陶瓷湿敏元件的性能研究

本文介绍了用金属氧化物陶恣材料制成的湿敏元件及其感湿特性，对陶恣材料的结构以及元件的感湿特性与陶材料结构的关系进行了初步的探讨。     

多晶硅湿敏元件的研究

用外延生长法,在具有二氧化硅层的单晶硅衬底上外延生长一层多晶硅,采用平面工艺在其上形成具有数千个矩形小孔的精密阵列,构成多晶硅阵列式湿敏元件.对元件的特性进行了研究,其吸湿响应时间为280ms,脱湿响应时间为620ms.在理论上,引入两种水分子与阵列作用机制,其一,水分子与多晶硅晶界的作用;其二,水分子与阵列结构的碰撞作用.由此计算了元件阻值随相对湿度变化的关系为R=R_0(1-Ax%)/(1+Dx%)将理论值与实验值进行比较, 两者吻合较好.     

高温高分子电容式湿敏元件的研究

分析研究了高分子电容式湿敏元件在高温高湿环境中输出电容值上漂的机理,阐明了选择湿敏材料、化学处理和改进元件结构的原则,并介绍了元件的性能。     

MSZ型湿敏元件及其应用

本文介绍的一是一种以高分子聚合物为主体材料的新型湿敏电阻元件，并对其工作原理，特点，技术参数，应用电路及制作方法作了具体阐述。     

High relative humidity measurements using gelatin coated long-period grating sensors

A long-period grating (LPG) coated with gelatin was developed as a high relative humidity (RH) sensor. The resonance dip or coupling strength of the LPG spectrum varies with RH. Experimental investigations on the sensor yield a sensitivity of 0.833%RH/dB with an accuracy of ±0.25%RH, and a resolution of ±0.00833%RH. The LPG RH sensor also offers repeatability, hysteresis and stability errors of less than ±0.877, ±0.203 and ±0.04%RH, respectively. In addition to the characterization of the LPG RH sensor, further studies were conducted to determine the effect of grating periodicities on the sensitivity of the sensor. Results show that higher order cladding modes from smaller grating periods enable the sensor to achieve higher sensitivity to humidity. This method is proposed to be more cost effective as compared to more complex spectroscopic methods based on wavelength detection. This sensor can also help to solve problems in measuring high humidity with existing relative humidity measurement systems.     

Thin polymer film based rapid surface acoustic wave humidity sensors

Polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) thin films, deposited on the surface of glass slides, were studied using transmission FTIR spectroscopy upon varying relative humidity (RH) from 2 to 70%. The obtained data revealed fast dynamics of water vapor adsorption-desorption with responses on the order of several seconds. Based on the fast FTIR signal intensity changes versus RH, it was proposed that a similar rapid response can be achieved for PVA and PVP coated SAW devices due to changes in mass-loading and film viscoelastic properties upon absorption of water vapor in the films. Sub-micron thickness films were spin-coated onto the surface of LiNbO₃ SAW substrates. Both PVA and PVP based humidity sensors revealed prompt reversible response to variations in humidity, although PVP-based device demonstrated better sensor parameters with total insertion loss variation of about 50 dB over the studied RH range and response time 1.5 s for the humidity step 5-95% (recovery time - 2.5 s), representing one of the fastest SAW-based humidity sensors reported to date.     

Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators

In this paper, two fiber-optic interferometric humidity sensors based on silica/polymer microfiber knot resonators (SMKR/PMKR) are reported. These tiny humidity sensors are directly fabricated by using silica/polymer microfibers without any humidity-sensitive coating. The silica microfiber knot resonator sensor has a humidity sensitivity of ∼12 pm/10%-RH within a linearity range from 15%-RH to 60%-RH, while the polymer microfiber knot resonators sensor has a humidity sensitivity of ∼88 pm/10%-RH, with a linearity range from 17%-RH to 95%-RH. The temporal response of the PMKR sensor is <0.5 s. Such types of humidity sensors have advantages of easy fabrication, fast response, extremely compact size, stable and low cost, they would find potential applications in micro-scale humidity sensing.     

基于Sensirion SHT系列传感器的分布式温湿度监测系统

设计了一种基于SensirionSHT温湿度传感器的温湿度监控系统.采用多级分布式结构和多单片机设计思想,系统由SensirionSHT温湿度传感器,单片机,嵌入式电力线载波调制解调器(PLC),和顶端服务器组成.主要完成了系统的软硬件设计,实现了一种面向物流仓储的温湿度监控系统.     

Fiber optic humidity sensors for high-energy physics applications at CERN

This work is devoted to a feasibility analysis for the development of novel fiber optic humidity sensors to be applied in high-energy physics (HEP) applications and in particular in experiments actually running at the European Organization for Nuclear Research (CERN). On this line of argument and due to the wide investigations carried out in the last years aimed to assess the radiation hardness capability of fiber optic technology in high energy physics environments, our multidisciplinary research group has been recently engaged in the development of near-field fiber optic sensors based on particle layers of tin dioxide to perform the monitoring of low values of relative humidity RH even at low temperatures.While this sensor type has been successfully employed for ppm and sub-ppm chemical detection in air and water environments, it is the first reported use for relative humidity measurements.The RH sensing performance of fabricated probes was analyzed during a deep experimental campaign carried out in the laboratories of CERN, in Genève. A very good agreement was observed between humidity measurements provided by the optical fiber sensors and commercial polymer-based hygrometers at 20 °C and 0 °C, with limits of detection for low RH regimes below 0.1%.     

基于LiCl湿敏涂层的QCM湿度传感特性的研究

对0.2%质量比LiCl薄膜涂层的QCM湿度传感单元湿敏特性进行了系统性的研究。研究结果表明:0.2%质量比LiCl—QCM的湿度传感单元的线性测量范围为13%～94%RH,克服了常规LiCl湿敏材料传感单元量程窄的缺点。另外,此湿度传感单元还具有重复性好、灵敏度高、湿滞小(小于10 Hz)、数字频率化输出等优点,因而,具有较好的潜在应用前景。     

Highly stable and sensitive humidity sensors based on quartz crystal microbalance coated with bacterial cellulose membrane

A novel highly stable and sensitive humidity sensor based on bacterial cellulose (BC) coated quartz crystal microbalance (QCM) has been successfully fabricated. The results showed that the sensors possessed good sensing characteristics by increasing more than two orders of magnitude with increasing relative humidity (RH) from 5 to 97%, and the Log(Δf) showed good linearity (20-97% RH). The sensitivity of sensors coated with BC membranes was four times higher than that of the corresponding cellulose membranes at 97% RH. In addition, the sensor sensitivity is greatly enhanced by increasing the coating load of the BC membranes with more absorption sites in the sensing membranes. Moreover, the experimental results prove that the resultant sensors exhibited a good reversible behavior and good long term stability. Herein, not only a novel and low-cost humidity sensor material was exploited, but also a new application area for BC nanofibrous membranes was opened up.     

基于光纤布拉格光栅湿度传感器的研究

文章基于光纤布拉格光栅对温度、湿度等敏感的基础上,分析了以聚酰亚胺（PI）薄膜为湿敏涂层,当湿度变化时,由于涂层的膨胀,导致光纤布拉格光栅产生应变,从而对湿度传感。理论分析与实验证明,光纤布拉格光栅湿度传感器是一种性能良好的湿度传感器。     

Study of the influence of nickel ions substitutes in barium stannates used as humidity resistive sensors

In the present work, we report the results of the influence of the Ni ions which partly substitute the Ba ions in the barium stannate (Ba_1−xNi_xSnO₃, where x = 0; 0.1; 0.2; 0.5), on the structural and electronic properties, as well as on the sensitivity to humidity. With the view to obtain a porous and finer structure, thus providing a high specific surface, these materials were obtained through the precursor method of self-combustion (co-precipitation in a colloidal environment and self-combustion), followed by heat treatments. The phase composition and morphology were studied by XRD and SEM. The pure sample, as well as that with the substitution x = 0.1, are single phased after 40 min sintering at 1000 °C. For substitutions with x > 0.1 secondary phases appear, which favorably influence the humidity sensitivity. All the samples show a significant sensitivity to humidity within 22% RH and 75% RH for the substitution with x = 0 and 0.1, and 22% RH - 98% RH for the substitution with x = 0.5. For this interval, the material resistivity logarithmically decreases by over four orders. The sample with the substitution x = 0.5 is characterized by a very fine structure (∼250 nm) and a high effective porosity (47%). This sample presents a shorter absorption response time than the other samples. Its high sensitivity, its sensitivity range, linearity of the sensitivity characteristic and the quick response time recommend the material with the composition Ba_0.5Ni_0.5SnO₃ for the realization of a very good resistive humidity sensor.     

多孔硅湿敏元件的频率特性

用多孔硅作为湿敏元件, 室温下在20Hz~100kHz频率范围,湿度从11%RH升至95%RH进行实验。结果表明:不同测试频率对多孔硅湿敏元件有较大影响,低频范围测量灵敏度高;高频范围效果不佳。讨论了频率影响的机理,其理论分析和实验结果一致。