High-temperature electrical properties of polymer-derived ceramic SiBCN thin films fabricated by direct writing

The in situ temperature monitoring of hot components in harsh environments remains a challenging task. In this study, SiBCN thin-film resistance grids with thicknesses of 1.8 μm were fabricated on alumina substrates via direct writing. Owing to their dense microscopic morphology and extremely high graphitisation level, the produced SiBCN films exhibited large high-temperature oxidation resistance and electrical conductivity. The resistance–temperature, stability, and repeatability characteristics of these films were examined in an aerobic environment at temperatures up to 800 °C. The obtained results revealed that the thermistor resistance decreased monotonously with increasing temperature from room temperature to 800 °C. The SiBCN film resistance variations observed during repeated temperature cycling in the regions of 505–620 °C and 610–720 °C were 0.09% and 1.7%, respectively. The high cyclability and stability of the SiBCN thin film thermistor suggested its potential applicability for the in situ temperature monitoring of hot components in harsh environments.     

大功率LED的温度补偿技术及其应用

采用温度补偿技术,是提高LED照明灯工作寿命的有效措施。阐述大功率LED的温度补偿方案及温度补偿的基本原理,分别介绍了LED驱动器、HB-LED驱动控制器的温度补偿电路设计。     

NTC热敏电阻的宽范围线性化分析与程序处理

NTC热敏电阻由于价格低廉,工业上经常用于替代热电偶或集成温度传感器进行环境温度测量,在批量生产时降低产品成本,但由于其电阻-温度的非线性极大,在温度的宽范围测量时,进行数据采集及微处理器系统处理可能会带来很大的误差.本文基于对HCS34B502F-E5015热敏电阻型温度传感器的数据分析,得出它在单片机系统中基于低成本考虑、V-F转换的温度测量方法.     

Thermistor behavior of PEDOT:PSS thin film

The temperature-dependent resistance changing characteristics (thermistor behaviors) of a poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate) (PEDOT:PSS) thin film are investigated in the 30–100 °C range using Greek-cross and bar patterns. The PEDOT:PSS film was spin-coated onto a Si wafer passivated with a SiO₂ layer, and a conventional dry etching technique was used to pattern the PEDOT:PSS film in conjunction with a nitride etch mask layer. Cr/Au was used for the electrode material. It was found that the characteristic temperature (T₀) and resistivity of the PEDOT:PSS film have an inversely proportional relationship with the number of coatings and the number of interfaces between multiply coated PEDOT:PSS layers. It was also found that as the number of coatings and the number of the interfaces increase, lower temperature-dependent resistance changes are observed. The temperature coefficient of resistance (TCR) value of 60 nm thick PEDOT:PSS film was slightly larger than or comparable to that of a conventional metal (Au or Pt) thermistor. The possibility of utilizing the PEDOT:PSS thin film in thermistor applications is discussed.     

基于热敏电阻的数字体温计

利用MSP430系列单片机集成的段式液晶驱动模块和16位Σ-Δ模数转换器,结合高温度系数的NTC热敏电阻,设计了一种高精度低功耗便携式数字体温计。详细介绍了该系统原理框架,NTC热敏电阻特性,AD温度采样原理,16位Σ-Δ模数转换器和软件的实现。在实际应用中以高精度、低功耗、测量时间短、方便携带等优点替代传统的水银体温计。     

大面积温场温度监测用热敏电缆（电阻型）的研究

研究了一种用于150～350℃温度区段大面积温场温度监测的热敏电缆。温度敏感材料为具有负电阻温度系数(NTC)的氧化物陶瓷。研制的热敏电缆(每支6m长)350℃电阻值大于100Ω,可达数千欧姆;在300℃放置1000h后电阻值漂移引起的温度偏差小于±5℃,经多次热循环(150～350℃)的温度偏差小于±5℃;平均无故障工作时间(MTBF)大于20000h。     

最佳非等距线性插值算法在热敏电阻测温中的应用

详细介绍了最佳非等距插值算法在热敏电阻测系统中的应用,给出了实现仿真的计算公式和有效数据。这种算法的运用,可以简化计算,提高运算速度。相对于等距离线性插值算法,最佳非等距线性插值算法可以有效降低插值表的数据存储空间。     

点热源热脉冲法测算生物流体的热物性参数

采用微珠状热敏电阻作为点热源和测温元件，在一维点源脉冲传热模型的基础上建立一种同时测量生物流体热扩散系数、导热系数和热容的瞬态方法。运用非线性参数拟合，直接从感温热敏电阻对热脉冲温度响应中同时获取待测的热物性参数。实验中设计了一个高灵敏度的温度测量电路，测试结果表明，本方法测量误差小于4％。此外，还讨论了测量数据的处理和影响测量的因素。     

单片机控制热熔焊机的硬件设计

针对当前可燃气体由传统的金属管道输送向高强度工程塑料管道输送转变的趋势,本文提出了一种在工程塑料管联接过程中专用的单片机控制热熔焊机的硬件和软件设计方案．     

Influence of doping BiYO3 and Nb2O5 on PTCR characteristics of BaTiO3 thermistor ceramics

Nb₂O₅-doped (1 − x)Ba_0.96Ca_0.04TiO₃-xBiYO₃ (where x = 0.01, 0.02, 0.03 and 0.04) lead-free PTC thermistor ceramics were prepared by a conventional solid state reaction method. X-ray diffraction, scanning electron microscope, Agilent E4980A and resistivity-temperature measurement instrument, were used to characteristic the lattice distortion, microstructure, temperature dependence of permittivity and resitivity-temperature dependence. It was revealed that the tetragonality c/a of the perovskite lattice, the microstructure and the Curie temperature changed with the BiYO₃ content. In order to decrease the room temperature resistivity, the effect of Nb₂O₅ on the room temperature resistivity was also studied, and its optimal doping content was finally chosen as 0.2 mol%. The 0.97Ba_0.96Ca_0.04TiO₃-0.03BiYO₃-0.002Nb₂O₅ thermistor ceramic exhibited a low ρ_RT of 3.98 × 10³ Ω cm, a typical PTCR effect of ρ_max/ρ_min > 10³ and a T_c of 153 °C.