Emissivity measurements of opaque gray bodies up to 2000 °C by a dual-frequency pyrometer

In the framework of the SPES project at LNL-INFN a method for emissivity measurements by a double-frequency pyrometer in the infrared region at high temperatures on opaque gray bodies of SiC and graphite is presented. The measurement method proposed in this work reveals a good fitting with literature values. Moreover, the effect of surface finishing on emissivity values has been investigated.     

Blue emission of ZrO2:Tm nanocrystals with different crystal structure under UV excitation

In this paper, thulium doped ZrO₂ nanocrystals with different phases were prepared by Pechini sol-gel complex method. The effects of host structure, phases and concentration on luminescence properties of Tm³⁺ ions were investigated. With the increase of the concentration of Tm³⁺ ions, the phosphors phase transformed from monoclinic to tetragonal structure and all the phosphors emitted blue light. However, because the environment symmetry around Tm³⁺ in m-ZrO₂ (C_2h) is worse than that of t-ZrO₂ (D_4h), there were still obvious differences in the emission and excitation. The reason was investigated with the help of energy level diagram. In addition, the quenching concentration of Tm³⁺ in ZrO₂ host is 1 m/m%.