变频式氧传感器输出特性的研究

介绍了一种新式氧化锆固体电解质变频式氧传感器,其结构由敏感电池和氧泵两部分复合构成。理论推导在浓差电势E1~E2范围的响应时间t与被测氧分压p1呈正比关系。实验测试数据显示:在保持浓差电势E1,E2在均不超过200 mV的范围时,时间t与被测氧分压p1之间的确呈现出非常好的正比关系,线性相关系数R均大于0.986。但当电势E1,E2超过200mV后,实验结果却与理论严重不符。经过初步分析,当浓差电势超过一定值后,空腔内的较低氧分压改变了固体电解质性质,使氧泵的电导率发生了变化导致理论推导的偏差。     

掺锶锰酸镧—二氧化锆氧气传感器的制备及其性能测试

利用喷雾热解所制务的Ｌａ０．８Ｓｒ０．２ＭｎＯ３超微粉末制作电极材料，用８ＹＳＺ超微粉制作固体电解质，制成了氧传感器，以Ｎ２－Ｏ２混合气体为待测气体，以空气为参比气体在不同的温度及氧分压下测量了该氧传感器浓差电势的大小。实验结果表明该氧传感器的输出电势与温度和氧分压的关系符合Ｎｅｒｎｓｔ方程并对氧分压的微量变化反应灵敏。回归得到的该氧传感器的实际刻度方程为：Ｅｍ（ｍＶ）＝０．０２４６Ｔ＋０．０４９     

基于BP神经网络的氧化锆氧量计的非线性补偿研究

氧化锆氧量计的工作原理是氧浓差电池原理,其氧浓差电势的计算是严重的非线性函数;选用只含一个隐含层的三层BP神经网络结构,充分利用BP神经网络的非线性函数逼近能力,无需模型只要适量的学习样本通过反复训练,即可按指定精度完成对氧化锆氧量计非线性特性的辩识和输出信号的非线性补偿;就隐含层节点数、学习率、误差指标等参数对该方法中BP神经网络训练次数和收敛过程的影响进行了比较研究。     

汽车用氧传感器de研究与进展

汽车尾气中的有害物主要有CO、HC、NOx、SOx以及一些微粒物质,给人类赖以生存的大气环境带来了严重的危害.用氧传感器对汽车发动机的空燃比进行调节,控制发动机中的燃烧过程,可以达到减少污染和节约能源的双重目的.目前适用于汽车空燃比控制的传感器主要有三种:氧化物半导体型(TiO2传感器)、浓差电池型(ZrO2氧传感器)、极限电流型.本文在介绍了这三种汽车用氧传感器的原理、结构的基础上,重点介绍了一种新型极限电流型氧传感器一致密扩散障碍层极限电流型氧传感器,并简要分析了其发展趋势.     

FET型氧传感器

<正> 氧传感器在工业过程检测、汽车发动机控制等领域已得到广泛应用。过去虽然已经研制出各种氧传感器,但迄今所使用的氧化锆氧传感器也只是限于克拉克型氧电极等产品。 氧化锆氧传感器由于工作温度在500℃以上,所以主要应用于过程测量和汽车方面。另外,氧化锆型氧电极虽然也可在室温条件下使用,但是需要电解质溶     

液体电解质氧传感器输出特性研究

对液体电解质氧传感器在不同氧体积分数、氧分压下的输出特性进行研究.测量氧传感器在不同氧体积分数、氧分压下的输出值,利用最小二乘法对输出值进行处理,得到氧传感器的输出特性曲线.对特性曲线进行分析,结果表明:液体电解质氧传感器对氧体积分数、氧分压的测量具有良好的线性度.压力冲击对传感器工作电极造成损害从而影响传感器性能,加入粉末冶金层能够克服这一问题,但传感器的响应时间有所增长.     

微机在高温氧化锆氧分析器温度修正中的应用

一、概述氧化锆氧分析器是60年代开始问世的一种新型测氧仪器。它是一种金属氧化物的陶瓷,在高温条件下具有传导氧离子,形成氧电势的特性,图1为锆管结构示意图及反应式。对于理想气体,反应所产生的电动势E符合能斯特(Vernst)公式 E=KTln P_o/P_x (1)式中K——常数 T——被测气体绝对温度 P_o——参比气体中氧分压值,即气体氧百分比浓度(简称参比氧浓度) P_x——待测气体中氧分压值,即待测气体氧百分比浓度(简称氧浓度) 由式(1)可知,若温度T被控制在某一定值上,并选一已知氧浓度的气体P_o(如空气)作为     

氧化镍氧传感器的研究

NiO是一种由金属缺位而形成的P型半导体,在较高的温度下(600℃以上),NiO材料的电阻率与氧分压有关,而且杂质对其性能影响很大。掺入一价杂质(Li_2O),材料电阻率降低,氧分压对其影响减弱;掺入三价杂质(Al_2O_3),材料电阻率增高,氧分压对其影响加强。据此,我们做出了直热式烧结型氧传感器,并将其用于气相色谱仪中,测量高纯气体(N_2,Ar)中微量氧,还制备了 Ni_(1-x)MgO_x材料的氧传感器,降低了还原性气体对测氧的干扰。     

汽车用氧化锆式氧传感器应用现状与发展趋势

介绍了氧化锆式氧传感器在汽车排放控制系统中的重要性,按照检测空燃比数值范围的宽窄对国内外现阶段主要的氧化锆式氧传感器进行了分类,对传统的"杯型"氧传感器、"平面型"氧传感器和新型空燃比传感器的结构组成、工作原理、信号特性及应用情况进行了介绍,重点论述了单元件型空燃比传感器和双元件型空燃比传感器的工作机理,比较分析了这几类氧化锆式氧传感器的优缺点,归纳得出了新型空燃比传感器将逐步取代传统氧传感器,未来能够满足检测范围宽、工作温度低、体积小的氧传感器将成为汽车氧传感器的发展趋势。     

用于燃烧效率分析的毛细管型电化学氧传感器

前言电化学氧传感器是化学传感器的重要组成部分。它在安全、环保、生物医学和工业过程等技术领域的监测和自动控制系统等方面有着广泛的应用。电化学氧传感器一般为隔膜型(Clark型)。它是利用氧穿过一层塑料薄膜的扩散极限电流来测定气体中或溶液中的氧分压(或浓度)。Tsueng首先提出利用氧气穿过毛     

Ce_(0.95)Ca_(0.05)F_(3-x)固体电解质氧传感器的研究

本文研究了Ce_(0.95)Ca_(0.05)F_(3-x)固体电解质及其氧传感器的制备和性质。在150℃时,Po_2在10~(-2)～10~(-1)MPa范围内传感器件的电位变化正比于Po_2的对数值。同时研究了不同参比电极和敏感电极对传感性能的影响。以Bi+BiF_3为参比电极时,EMF值稳定较快;当Pd作为敏感电极时,传感元件的响应较快;以RuO_2作敏感电极时,传感器件较灵敏。文章还讨论了敏感机理。     

Hydrogen sensor based on antimonium pentoxide-phosphoric acid solid electrolyte

A solid composite electrolyte with high proton conductivity based on antimonium pentoxide with additives of phosphoric acid has been obtained. A potentiometric solid-state gas sensor using this electrolyte has been developed for detecting small amounts of hydrogen (10–2000 ppm) in gas mixtures at ambient temperature. The sensor consists of the reference electrode: Ag or Ag/(Ag + Ag₂SO₄), the solid composite electrolyte and H₂-sensitive electrode: Pt or Pd. The electromotive force (e.m.f.) of the sensor varies logarithmically with H₂ concentration for hydrogen partial pressures in the range 100–2000 ppm and depends on the oxygen partial pressure. The slope of e.m.f.-log(pH₂) dependence is 170 and 200 mV for Pt and Pd, respectively, which exceeds the Nernst value, presumably due to the formation of a mixed potential. The sensor can operate at a wide range (20–95%) of a relative humidity.     

An auto-calibrated miniature microhole cathode array sensor system for measuring dissolved oxygen

The electrochemical dissolved-oxygen sensor is a powerful tool in medical, biological and environmental applications. The authors have developed a new auto-calibrated miniature microhole cathode array sensor for measuring dissolved oxygen and ionic conductivity. Operating in the three-electrode potentiostatic mode, the sensor consists of two identical gold working electrodes with a multiple-cathode array, and Ag/AgCl reference electrode, a gold counter electrode and a Pt thermal resistor. One of the working electrodes is used for oxygen measurement and the other for calibration. The two working electrodes can also be used to measure the conductance of a solution by switching the sensor over to a conductance-measuring circuit. Evaluation of the sensor characteristics has given promising results. A linear relationship is observed for calibration of the sensor over the oxygen concentration range 3–16 ppm in 0.1–1.0 N KCl solution at 12–25°C and 760 Torr pressure. Each sensor can work stably and continuously for more than 20 h.     

基于固态Ag/AgCl参比电极的氧化钨pH电化学传感器的研究

通过浸涂法在钨金属丝上涂敷氧化钨氢离子敏感膜,制备了氧化钨H 选择性电极,采用尿素改性聚乙烯醇作为参比电极的固态薄膜材料并进行KCl掺杂,经Nafion膜进行修饰后制备了固态参比电极.利用自制的氧化钨pH电极与固态参比电极制成pH电化学传感器,该传感器具有良好的响应电位E-pH线性函数关系,响应范围为pH2～pH11.响应灵敏度与氧化钨的热处理温度有关,200℃热处理后的响应灵敏度为52.81 mV/pH, 响应时间与氧化钨敏感膜、测试溶液pH值以及溶液温度有关.在pH2→pH11→pH2循环测试过程中,传感器的滞后效应较小.该传感器有良好的选择性,响应行为不受Na 、F-等常见离子的影响,但是受到氧化还原性的NO-3、I-等离子的干扰.传感器内阻很低为22.8 kΩ,远小于玻璃pH计的内阻(1×109 Ω).该传感器在各种饮料中具有较高测量精度,与玻璃pH计的测量值进行对比,两者的差值在(-0.06 pH, 0.15 pH)范围内.在10-5M→10-1M柠檬酸溶液中,传感器的响应电位与溶液浓度存在良好的线性关系,响应时间小于1 min.     

Electrochemical studies on the performance characteristics of alkaline solid embeddable sensor for concrete environments

In this study, alkaline solid embeddable MnO₂ is used as a reference sensor for concrete environments. The performance characteristics are evaluated in a saturated calcium hydroxide solution, a synthetic concrete pore solution and ordinary Portland cement (OPC) extracts which correspond to the concrete environments. The electrochemical stability of the MnO₂ electrode is studied in the said concrete environments. The uniformity of the MnO₂ sensor is tested in concrete environments. The reversibility of MnO₂ sensor in three alkaline solutions is within ±10 mV, which is very well within the limit as sensor for concrete. The polarization behaviour of MnO₂ electrode in concrete environments is carried out potentiodynamically and impedance behaviour showed the stability of sensor. All the studies revealed that MnO₂ as a suitable sensor electrode for concrete structures.     

Performance of glucose biosensor based on oxygen electrode in physiological fluids and at body temperature

A potentially implantable glucose biosensor for continuous monitoring of glucose levels in diabetic patients has been developed. The glucose biosensor is based on an amperometric oxygen electrode and glucose oxidase immobilized on carbon powder held in the form of a liquid suspension. The enzyme material can be replaced (the sensor recharged) without sensor disassembly. Diffusion membranes made of silastic coatings over a microporous polycarbonate membrane are used. Calibration curves of the sensors in phosphate buffer solution and in undiluted blood plasma at body temperature have been obtained. The reproducibility of the sensor response in serum at body temperature is demonstrated. The sensors have a stable signal during storage and continuous operation at body temperature for a period of at least one month.     

Oxygen sensors based on a new design concept for amperometric solid state devices

A new design for all-solid amperometric detectors was tested as an oxygen sensor in the 1%–25% v/v concentration range. The design consisted of both the working (WEs) and counter electrodes (CEs) being vacuum-deposited as non-porous Au layers on the same face of a Nafion® membrane and in contact with the gas sample. Both a three-electrode device (the reference electrode being a strip of Ag/AgCl inserted between the two Au layers) and a two-electrode one were tested. In the former case, the sensor exhibited good linearity with oxygen concentration, response times comparable to a commercial sensor but a strong dependence on humidity. The origin of the latter is not due to ohmic losses but rather to the loss of catalytic activity with decreasing water contact in the polymer. The two-electrode device exhibits signal saturation at high oxygen concentrations, which is interpreted by limitations imposed by the CE reactivity. In both cases, oxygen reduction led to an exponential current rise over a wide potential range indicating very high mass transport rates and implying that the electroactive gas reacts at the line formed by the gas/solid electrolyte/metal layer interface.     

基于LSCM/3YSZ致密扩散障型极限电流氧传感器的研究

采用固相法制备了LSCM(La0.75Sr0.25Cr0.5Mn0.5O3)粉体。按不同质量比将其与3%-mol氧化钇稳定氧化锆粉体(3YSZ)混合,制备得到系列混合导体。根据热膨张系数、微观形貌等物理特性,选取合适比例的混合导体。采用Pt浆粘合法将其与8YSZ固体电解质叠层制作成致密扩散障型极限电流氧传感器。经测试,使用LSCM质量比分别为60%和70%的混合导体作为致密扩散障时,对应的氧传感器在973 K氧浓度分别为6 000×10-6～2.28%和1.22%～8.01%范围内具有良好的测氧特性,并且极限电流与氧浓度之间存在良好的线性关系;其在不同氧浓度下的响应时间曲线显示传感器重复性好,响应时间约数十秒。     

双敏传感器稳定性的研究

双敏传感器是一种新型的传感器.在其研究过程中,传感器的稳定性是一个急需解决的难题.实验中在原有的敏感材料基础上添加Nb2O5材料.对所做成的元件进行两年多的性能参数的跟踪测试.测试表明元件的稳定性较好.通过XRD,SEM,TEM实验对敏感材料进行微观分析.表明掺杂后的敏感材料在烧结后形成固溶体及部分固溶体状态.材料的固溶状态使元件的气、湿敏性能保持在稳定状态.     

极限电流型氧传感器的研究

极限电流型氧传感器工作原理是基于稳定ZrO2固体电解质的氧泵作用,通过气体扩散控制供给阴极的氧而得到极限电流。基于该原理,研制了用ZrO2固体电解质和多孔陶瓷基片作为扩散层构成的多孔层型氧传感器。在N2-O2混合气体中,对传感器的性能进行测试,结果表明:传感器的测量范围为0~10%氧摩尔分数时,灵敏度为0.5mA/10-2,工作温度为650~800℃,线性度为±5%。