基于LabVIEW平台的形状记忆合金温度循环加载控制装置研究

本文根据NiTi形状记忆合金热-力耦合循环变形实验的要求,针对传统加热方法变温速度慢、温度变化非线性、加热不均匀,且无法与其他装置配合使用等缺点,提出了一种新型形状记忆合金温度循环加载控制装置。该装置基于电流加热方法,使用测温仪表进行测温,采用直流电源与降温组件进行变温,同时利用PID等控制方法进行控制,达到精准控温的效果。通过测试及实验,可以看出,该装置具有良好的控温性能、快速的变温速度、自动的程序控制等优点。本装置的成功开发为形状记忆合金热-力耦合循环变形和疲劳失效行为的实验研究提供了坚实的设备基础。     

Local structure and optical absorption characteristic investigation on Fe doped TiO2 nanoparticles

The local structures and optical absorption characteristics of Fe doped Ti O2 nanoparticles synthesized by the sol-gel method were characterized by X-ray diffraction(XRD), X-ray absorption fine structure spectroscopy(XAFS) and ultraviolet-visible absorption spectroscopy(UV-Vis). XRD patterns show that all Fe-doped Ti O2 samples have the characteristic anatase structure. Accurate Fe and Ti K-edge EXAFS analysis further reveal that all Fe atoms replace Ti atoms in the anatase lattice. The analysis of UV-Vis data shows a red shift to the visible range. According to the above results, we claim that substitutional Fe atoms lead to the formation of structural defects and new intermediate energy levels appear, narrowing the band gap and extending the optical absorption edge towards the visible region.