共查询到19条相似文献,搜索用时 89 毫秒
1.
Fe_2O_3系气敏元件热特性定量描述 总被引:2,自引:2,他引:0
通过测试某厂生产的Fe2O3系烧结型旁热式气敏元件在不同加热条件下空气中的阻值,分析了大量数据,总结出正常条件下元件阻值Ra随加热电流IH(电压VH)变化规律,给出经验公式,以利于获得最佳工艺条件。 相似文献
2.
3.
本文报道了用TiO_2/SnO_2陶瓷制成的实芯园盘湿敏元件的阻值稳定性与水吸附性质的关系的研究。研究了由于水的化学吸附形成的羟基团使湿敏的阻值增加与陶瓷微观结构间的相互关系;陶瓷的微观结构是通过分析扫描电镜,粉末法X射线衍射的数据和通过在充满水气的真空中使湿敏阻值变化的试验的方法得到的。此外,还让湿敏元件在大气中,外加100Hz交流脉冲的情况下,进行了3000小时的寿命试验。最后,通过介绍陶瓷湿敏元件的简化等效电路的方法,讨论了未加热的湿敏元件实际应用的可能性。 相似文献
4.
为了研究WO3的常温气敏性能,以热氧化钨丝的方法制备WQ3纳米材料并制作厚膜气敏元件,通过XRD对材料的晶体结构进行表征,对敏感元件进行了气敏性能测试,测得该元件在常温、0.4W/cm2紫外光(波长:300~450nm)辐照条件下对50ppm的NO2的灵敏度S=15.4,响应时间τres=2.5s,恢复时间τrec=18.1s;在加热功率为0.81W条件下,元件对50ppm NO2的灵敏度为S=22.5,响应时间τres=1.5s,恢复时间τrec=10.7s,研究了灵敏度对光功率密度和加热功率的依赖关系,实验结果表明WO3纳米材料在常温、紫外光照条件下对NO2具有较好的气敏性能. 相似文献
5.
6.
热敏电阻的阻值会随温度的变化而变化,它是接触式温度传感器的核心元件。能否准确得到阻值与温度的关系直接影响到温度传感器测量值是否准确。但是阻值与温度的关系并非简单的线性关系,本文讨论了基于实验数据采集与多项式回归的方法建立热敏电阻阻值与温度关系数学模型,并得到对应解析表达式的过程。 相似文献
7.
<正> 对珠状玻璃杆密封测温型(MF51型)热敏电阻,分两组进行了稳定性试验。第一组元件进行一周时间内的短期复现性的高精度测定,第二组元件考查了它们在长到五年四个月内室温贮存条件下阻值的漂移。测定结果表明,其短期和长期稳定性可与国外同类产品比美,足以在中温范围内作精密温度传感元件使用。 受试的第一组热敏电阻16支全由北京玻璃所生产。测试在国家计量院热工处进行。测 相似文献
8.
研究了环境温度变化对各种元件气敏特性产生的影响突出地表现为随着
环境温度的降低一℃ , 气敏元件在空气中的阻值。明显增大用有机硅化物
处理元件的表面可减小元件凡的这种漂移 相似文献
9.
佳能激光印字机在国内印刷行业中占据主要地位,由于其结构精密,且鲜有资料,维修较难。现将笔者维修中的部分实例发表,以供参考。 1.故障现象:一台ST激光印字机,始终不加热。 分析检查:此情况有两种可能,一是加热灯管损坏,或是加热控制部件损坏。先拆下加热组件,测量加热定影灯管阻值为8欧左右,正常。若阻值为无穷大,则灯管被烧断,需要换加热灯管。在灯丝回路中还串联了一只温度开关,其作用是当加 相似文献
10.
11.
13.
Jensen B.D. Chow L.L.-W. Kuangwei Huang Saitou K. Volakis J.L. Kurabayashi K. 《Journal of microelectromechanical systems》2005,14(5):935-946
This paper explores contact heating in microelectromechanical systems (MEMS) switches with contact spot sizes less than 100 nm in diameter. Experiments are conducted to demonstrate that contact heating causes a drop in contact resistance. However, existing theory is shown to over-predict heating for MEMS switch contacts because it does not consider ballistic transport of electrons in the contact. Therefore, we extend the theory and develop a predictive model that shows excellent agreement with the experimental results. It is also observed that mechanical cycling causes an increase in contact resistance. We identify this effect as related to the build-up of an insulating film and demonstrate operational conditions to prevent an increase in contact resistance. The improved understanding of contact behavior gained through our modeling and experiments allows switch performance to be improved. 相似文献
14.
Mingxiang Chen Xiaohui Song Sheng Liu Zhiyin Gan Qiang Lv 《Microsystem Technologies》2012,18(6):679-682
A novel batch welding of aligned carbon nanotubes (CNTs) onto metallic electrodes is developed by radio frequency induction heating. The experiments had achieved optimum contact between CNTs and metal electrodes, two hundred samples had the same trend of reduction of contact resistance after heating process, and this reduction was irreversible, which demonstrated good reproducibility of induction heating for CNT welding. Because of its non-contact and selective heating, induction heating provide a potential approach to reproducible large-scale fabrication and wide applications of CNTs devices. 相似文献
15.
林开生 《自动化技术与应用》2011,30(8):74-78
介绍一种基于热泵式除湿结构的恒温恒湿空调,其气液系统具有独特的结构设计,气液系统巾的四通阀和电磁阀由计算机控制,实现制冷、制热和除湿.这种系统没有阻性元件加热装置,与带阻性元件加热装置的恒温恒湿空调相比节能60%(除湿时).采用可编程数字温湿度传感器和基于可编程芯片的各种接口电路,使得测控系统硬件更简单、工作可靠性更高... 相似文献
16.
17.
A steady flow combined heat pump cycle model with heat resistance, heat leakage and internal irreversibility is built in this paper. The optimal performance of the model is studied. The relation between optimal heating load and coefficient of performance (COP), as well as the maximum COP and the corresponding heating load are derived. 相似文献
18.
Lei Xie Thalke Niesel Monika Leester-Schädel Gerhard Ziegmann Stephanus Büttgenbach 《Microsystem Technologies》2013,19(7):1017-1023
Variotherm is special mould temperature controlling concept which realizes the rapid heating/cooling of mould during material processing in order to extend the freezing time of materials. A novel variotherm concept based on silicon wafer combined with micro electric resistance heating structures is purposed and prototyped in this study. The manufacture process of this variotherm unit was introduced and its heating/cooling performance was tested and analyzed by thermal graphic method, which indicate that the new variotherm concept has excellent thermal control efficiency and precise temperature distributions. 相似文献