燃气轮机专用高温温度传感器

基于燃气轮机高温温度测量与控制,研制了一种燃气轮机专用高温温度传感器。该传感器采用测量范围宽的热电偶为感温元件,具有响应速度快、性能稳定、抗振动、耐冲击、工作寿命长、成品率高、适合于批量生产等特点。它不仅可用于军用装备中,也可用于移动电站、石油平台、矿山、化工及地下工程等领域。     

Silicon hotplates for metal oxide gas sensor elements

 Low-power-consumption metal oxide gas sensors and gas sensor arrays can be produced by combining micromachining and thin-film technologies. In the present paper the state-of-the art in this field is reviewed. In the first part the problem of thermal losses from a heated metal oxide film is addressed and the necessity of miniaturisation of gas sensing devices is pointed out. The thermal properties of realized silicon hotplates are compared and analysed with respect to thermal equivalent circuit models. In addition, the results of accelerated thermal ageing tests are presented. These latter results demonstrate that micromachined heater elements are likely to exhibit device lifetimes of the order of 30 years when operated at membrane temperatures around 400 °C. In the second part of the paper attention is drawn to novel methods of gas detection which are enabled by employing stacks of different thin film materials on micromachined hotplates. In this context, recent results on temperature-and field-effect modulated gas detection experiments are discussed. Received: 16 May 1997 / Accepted: 22 May 1997     

氧化锡气敏传感器动态响应特性用于农药残留检测的研究

本文介绍了氧化锡气敏传感器参杂金属(Sb,Ca,Sr)的制备及检测农药残留检测装置的原理,通过对氧化锡气敏传感器,在动态与静态条件下,检测农药残留的响应特征及影响因素进行了研究,如采用电压、占空比、电压波形(矩形波、正弦波、锯齿波、脉冲波)的变化,比较研究了农药残留检测的动态与静态响应特征,结果表明动态的测量方法比静态方法可以得到更多的信息,用这种动态测量方法检测对硫磷等有机磷类农药残留具有良好效果。     

A nitric oxide gas sensor based on Rayleigh surface acoustic wave resonator for room temperature operation

A Rayleigh surface acoustic wave (RSAW) resonator with polyaniline/tungsten oxide nanocomposite thin film is investigated as a gas sensor for detecting the presence of nitric oxide (NO) in air. The sensor developed in this work was sensitive to NO gas at room temperature. It is shown that the sensor had a frequency shift of 1.2 ppm when it was exposed to 138 ppb NO. The negative frequency response increased with NO concentration increasing. The response and recovery times of the NO sensor in this work were about 20-80 s. In addition, this RSAW sensor also exhibited reversibility and repeatability to the presence of NO gas. Especially, the presented sensor showed high selectivity with NO gas to separate from NO₂ and CO₂ gases.     

石墨烯/氧化钨复合材料室温响应NO2传感器

采用溶剂热法制备了石墨烯/氧化钨复合材料,通过XRD,SEM,Raman表征方法对复合材料形貌、晶体结构进行表征,结果表明:制备的氧化钨为六方相结构的WO3,呈现一维管状形貌,石墨烯均匀分散在复合材料中.石墨烯/氧化钨复合材料涂覆在叉指电极制作成传感器进行气敏性能测试,结果表明:传感器可室温条件下实现对NO2检测,检测...     

Development of high sensitivity tin oxide based sensors for gas/odour detection at room temperature

An effort has been made to develop thick film tin oxide gas sensors which could detect various gases/odours at room temperature. To achieve this, the fabricated sensors were annealed in oxygen plasma for various durations. It was then found that, the room temperature sensitivity of such sensors was increased to about ten times as compared to the sensitivity of the non-annealed sensors. Further, plasma annealed sensors are found to be practically independent of temperature and the room temperature sensitivity of these sensors are found to be about 1.5 times the sensitivity of the conventional sensors at its operating temperature of 300°C. Studies on the variation of d.c. resistance, sensitivity, temporal response, current–temperature characteristics and impedance spectroscopy with the annealing time have also been made. These studies reveal that, with the increase in annealing time, there is a permanent gradual reduction in the d.c. resistance of annealed sensors. Further, it is also observed that with the increase in annealing time, the response time improves, barrier height reduces, barrier capacitance increases and the dependence of the sensitivity with temperature reduces while the sensitivity itself improves many-fold.     

高体积分数溴气传感器

描述了目前溴气传感器的发展状况,介绍了一种用于高体积分数测量的溴气传感器,阐述了它的工作原理,对电极材料、薄膜材料、电解液、电路等关键技术进行了讨论,给出了它的结构,讨论了性能特点及影响因素。     

一种SiC高温温度传感器

理论表明,当流过SiC肖特基势垒二极管的正向电流恒定时,在一定温度范围内,器件两端的正向压降与温度变化之间存在线性关系。利用此特性,可以制造SiC高温温度传感器。阐述了SiC高温温度传感器的工作原理、结构特点和工艺过程,介绍了传感器系统的结构。系统的测温范围在0～500℃,测量准确度可达0.5℃。     

高温转速传感器的研制

介绍了非接触磁电式转速传感器的基本原理、结构设计及磁路计算,给出了试验数据,并对测试结果进行了分析。讨论了高磁性材料在高温环境下的应用。     

高选择性常温NH_3传感器

采用MEMS技术,如KOH腐蚀、光刻、溅射金属等技术,在硅片、玻璃等材料上制得平面式微传感器管芯,此结构具有微型化、低功耗、一致性好、适宜大批量生产的优点。敏感材料的采用不同于传统无机物,而是以苯胺为原料,合成高分子聚合物———聚苯胺,此敏感材料不需要加热源,其电阻在室温下与NH3浓度成一定函数关系,可以测得空气中较低含量的NH3。聚苯胺的另一个显著优点是高选择性,实验表明,高达1000×10-6(气体体积分数)的H2,CH4,CO,C4H10,C2H5OH的灵敏度远低于50×10-6(NH3气体体积分数)的灵敏度。     

超高频无线温度传感系统

针对不利铺设线路的环境中进行多点的温度测量与数据采集,提出了一种基于超高频2.45 GHz的无线温度传感系统的设计方案。采用数字温度传感器进行温度采集,并通过无线方式与主机进行数据通信,完成数据无线通信、编解码、显示、存储等功能。系统测量范围为-10~55℃,精度可达0.125℃。最后,对测量的数据进行统计与分析,并得出相应的结论。     

燃气总温传感器的设计

研究了总温传感器的滞止理论,并在此基础上设计了一种滞止罩结构。为了初步验证滞止罩设计的合理性,采用数值方法对总温传感器滞止罩进行流固耦合模拟,获得了滞止罩内燃气流的速度分布及滞止罩内传感器测量端表面的温度分布,系统分析从数值模拟中提取的数据,得到的结果表明该设计能提高传感器对高速高焓燃气温度测量的准确度。     

高温压力传感器的力敏电阻条的制备

本文探讨了一种金属薄膜高温压力传感器的力敏电阻条的制作方法,采用氮化铝作铜村底和金属力敏电阻条之间的电绝缘层,利用铜金属在高温条件下也能够表现出压阻特性,制作力敏电阻条。通过直流磁控溅射制作力敏电阻条,并引线,封装,进行测试,最后反应出随压力的变化电阻的变化关系。     

金属氧化物气敏元件稳定性的研究进展

金属氧化物气敏元件性能的不稳定制约了元件的实用化进程,气敏元件稳定性的研究成为气体传感器技术中的一项重要内容。概述了金属氧化物气敏元件稳定性的研究进展,介绍了敏感材料、敏感材料的制备工艺、载体材料、加热/测量电极等因素对稳定性的影响。分析了各种影响因素的作用机理,并对其研究前景进行了展望。     

高温压力传感器温度漂移补偿研究

针对高温压力传感器耐高温和高压的测量的要求,设计了压阻式压力传感器硅杯式芯片版图,采用SIMOX(separationbyimplantedoxygen)技术SOI(silicononinsulator)晶片,在微加工平台上制作了该芯片,获得了差动等臂等应变的惠斯登检测电桥。对采用耐高温封装后的传感器的热零点漂移、热灵敏度漂移和零位输出的补偿作了研究,设计了补偿电路,推导了热灵敏度漂移补偿的计算公式,在通用型高温压力传感器的研发中证明其可行性和实用性,并总结出了经验公式。     

Design and optimization of heating plate for metal oxide semiconductor gas sensor

A thin film was coated onto the top of the heating electrodes to reduce the power consumption and improve the uniformity of temperature distribution. Finite element simulation software COMSOL was used to simulate the effect of coating materials and dependence of thicknesses of the coating film on the power consumption of the heating plate. On the basis of simulation, the temperature distribution of different heating plates was measured using infrared thermography. Experiments have showed that the power consumption of the heating plate can be significantly reduced and the temperature uniformity is promoted with adding the coating film on the top of the heating electrodes. The response of the gas sensor based on PdO-WO₃ nanoparticles was characterized with analyte of acetone. It was found that the addition of the coating film could enhance the response to acetone. In addition, the response speed of sensors was investigated with coating films and the results indicated that with the coating film sensor response speed became faster.

     

集成温度传感器原理及应用

介绍了三种不同输出类型（电压、电流和数字信号）的集成温度传感器的特性、工作原理,并结合实验教学,对每一类中典型温度传感器给出了实际应用电路和测试结果。     

集成于无源RFID标签的温度传感器设计

针对无源无线射频识别(RFID)标签的低功耗设计要求,设计了一种基于环形振荡器的CMOS温度传感器.该传感器首先产生一个与绝对温度成正比PTAT电流,然后通过环形振荡反相器来产生相应的PTAT频率,最后利用计数器来实现频率-数字之间的转换.测试结果表明:该温度传感器实现了125nW的超低功耗,在-40~80℃范围内,误差仅为-0.7/1.2℃,特别适合集成于无源RFID标签中.     

Electrical properties of nickel oxide thin films for flow sensor application

In this work, Ni oxide thin films, with thermal sensitivity superior to Pt and Ni thin films, were formed through annealing of Ni films deposited by a r.f. magnetron sputtering. The annealing was carried out in the temperature range of 300–500 °C under atmospheric conditions. Resistivity of the resulting Ni oxide films were in the range of 10.5 μΩ cm/°C to 2.84 × 10⁴ μΩ cm/°C, depending on the extent of Ni oxidation. The temperature coefficient of resistance (TCR) of the Ni oxide films also depended on the extent of Ni oxidation; the average TCR of Ni oxide resistors, measured between 0 and 150 °C, were 5630 ppm/°C for the 300 °C and 2188 ppm/°C for 500 °C films. Because of their high resistivity and very linear TCR, Ni oxide thin films are superior to pure Ni and Pt thin films for flow and temperature sensor applications.     

Studies on SiC, DLC and TiO2 thin films as piezoresistive sensor materials for high temperature application

The use of thin films as sensing elements for microsensor applications has been shown very attractive due to their low-cost fabrication, potential for integration with standard CMOS technologies and possibility of deposition on different substrate types. In particular, piezoresistive sensors based on thin films have been commonly developed because can be easily implemented using microfabrication processes and present the best relation between sensitivity and system complexity, which showing great advantages in term of device integration. In our previous works (Fraga et al. 2010, 2011a), we studied undoped and nitrogen-doped PECVD a-SiC thin films as alternative materials to replace the silicon piezoresistors in strain and pressure sensors for harsh environments. Here, we focused our attention on the piezoresistive properties of sputtered silicon carbide (SiC), diamond-like carbon (DLC) and titanium dioxide (TiO₂) thin films. These materials were evaluated in terms of sensitivity or gauge factor and of the influence of the temperature on this sensitivity, allowing a preliminary analysis of the applicability of these thin films in high temperature piezoresistive sensors.