PDF(Pubmed)
Abstract：
Air pollution has been associated with several health problems. Detecting and measuring the concentration of harmful pollutants present in complex air mixtures has been a long-standing challenge, due to the intrinsic difficulty of distinguishing among these substances from interferent species and environmental conditions, both indoor and outdoor. Despite all efforts devoted by the scientific and industrial communities to tackling this challenge, the availability of suitable device technologies able to selectively discriminate these pollutants present in the air at minute, yet dangerous, concentrations and provide a quantitative measure of their concentrations is still an unmet need. Thermal conductivity detectors (TCDs) show promising characteristics that make them ideal gas sensing tools capable of recognising different gas analytes based on their physical fingerprint characteristics at the molecular level, such as their density, thermal conductivity, dynamic viscosity, and others. In this paper, the operation of TCD gas sensors is presented and explored using a finite element simulation of Joule heating in a sensing electrode placed in a gas volume. The results obtained show that the temperature, and hence, the resistance of the individual suspended microbridge sensor device, depends on the surrounding gas and its thermal conductivity, while the sensitivity and power consumption depend on the properties of the constitutive metal. Moreover, the electrode resistance is proven to be linearly dependent on the applied voltage.
摘要：
空气污染与一些健康问题有关。检测和测量复杂空气混合物中存在的有害污染物的浓度一直是一个长期的挑战，由于将这些物质与干扰物种和环境条件区分开来的内在困难，室内和室外。尽管科学界和工业界竭尽全力应对这一挑战，是否有合适的设备技术能够在一分钟内选择性地辨别空气中存在的这些污染物，然而危险，浓度并提供其浓度的定量测量仍然是一个未满足的需求。热导检测器（TCD）显示出有前途的特性，使其成为理想的气体传感工具，能够根据分子水平的物理指纹特征识别不同的气体分析物，比如它们的密度，热导率,动态粘度,和其他人。在本文中,使用放置在气体体积中的感测电极中的焦耳加热的有限元模拟来呈现和探索TCD气体传感器的操作。获得的结果表明，温度，因此，单个悬挂式微桥传感器装置的电阻，取决于周围的气体和它的导热性，而灵敏度和功耗取决于本构金属的性质。此外，电极电阻被证明是线性依赖于所施加的电压。
