有害气体检测传感器技术进展

介绍有害气体检测传感器研究进展。气体检测传感器主要有催化燃烧式传感器、热导式传感器、电化学传感器、红外传感器、金属氧化物半导体传感器、碳纳米管传感器等,基于气体传感器的检测原理,综述了常用气体检测器的应用范围和局限性。催化燃烧式传感器可以灵敏地检测爆炸下限以下可燃气体的浓度,但需注意防止其暴露于高浓度气体环境中;热导式传感器无需氧气供应,适用于检测热导率比空气高的低相对分子质量气体;电化学传感器对检测环境的温度、湿度变化敏感,适用于检测具有电化学活性的气体;红外传感器无需定期校准,适用于检测腐蚀性和反应性气体,但无法检测单质气体;金属氧化物半导体传感器可在高温环境下工作,并能灵敏地检测浓度为10^–9 mol/mol的气体;碳纳米管传感器只能用于检测强氧化还原性气体,通过对碳纳米管材料进行修饰改造可扩展其应用范围。最后对气体检测传感器的发展进行了展望。     

Theoretical investigation of ferromagnetic resonance in a ferromagnetic thin film with external stress anisotropy

We use the ferromagnetic resonance(FMR)method to study the properties of ferromagnetic thin film,in which external stress anisotropy,fourfold anisotropy and uniaxial anisotropy are considered.The analytical expressions of FMR frequency,linewidth and the imaginary part of magnetic susceptibility are obtained.Our results reveal that the FMR frequency and the imaginary part of magnetic susceptibility are distinctly enhanced,and the frequency linewidth or field linewidth are broadened due to a strong external stress anisotropy field.The hard-axis and easy-axis components of magnetization can be tuned significantly by controlling the intensity and direction of stress and the in-plane uniaxial anisotropy field.