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This work using first-principles theory studies the sensing properties of Cu-decorated GaN (Cu–GaN) monolayers as a promising candidate for the detection of CO and HCHO in dry-type transformers. The Cu dopant prefers to be trapped on the TN site of the GaN surface with an E b of −1.13 eV. Chemisorption is identified for the two gas adsorption systems, given the large adsorption energy (E ad) of −1.35 and −1.09 eV. Caused by the chemisorption, the electronic property of the Cu–GaN monolayer is significantly deformed, narrowing its band gap of 0.548 eV to 0.00 eV, exhibiting metallic property, in two gas systems. Combined with the desirable recovery property for CO and HCHO desorption from the Cu–GaN surface, it could be proposed that the Cu–GaN monolayer is a promising gas sensor for toxic gas detection in dry-type transformers, so as to evaluate the operation status of the power system and guarantee safe working conditions for the maintenances.

In comparison with single crystal scintillators, glass scintillators are more promising materials for their benefits of easy preparation, low cost, controllable size, and large-scale manufacture. The emission of Eu3+ ion at 612 nm matches well with the photoelectric detector, making it suitable for the activator in glass scintillators. Therefore, the research on Eu3+ doped glass scintillators attract our attention. The photoluminescent and scintillating properties of Eu3+-activated boroaluminosilicate glass scintillators prepared by the conventional melt-quenching method were investigated in this work. The glass samples present good internal quantum yield. Under X-ray radiation, the optimal sample reveals high X-ray excited luminesce (XEL), and its integrated intensity of XEL is 22.7% of that of commercial crystal scintillator Bi4Ge3O12. Furthermore, the optimal specimen possesses a spatial resolution of 14 lp/mm in X-ray imaging. These results suggest that Eu3+-doped boroaluminosilicate glass is expected to be applied in X-ray imaging.