In this study, the gas-sensing mechanism of ZnO, TiO2, and Ag2O modified SnS2 toward dissolved gases (CO, CH4, C2H2, and C2H4) in transformer oil were studied based on the density functional theory. The modified structure, adsorption structure, band structure, adsorption energy, charge transfer, deformation charge density, density of states, and molecular orbit were analyzed. The results show that the conductivity of SnS2 monolayer is improved to a certain extent after surface modification with ZnO, TiO2, and Ag2O. And the adsorption of CO, CH4, C2H2, and C2H4 on the intrinsic SnS2 monolayer is weak physical adsorption. Compared with the intrinsic substrate, the adsorption energies of MO-SnS2 (M=Zn, Ti, Ag2) monolayer for the four target gases have been increased to different degrees, except that the adsorption energy of TiO2-SnS2 for C2H4 molecule has decreased slightly. With deformation charge density, density of states and molecular orbital analysis, it can be concluded that ZnO-SnS2 and TiO2-SnS2 have good gas sensitivity to CO, C2H2, and C2H4 molecules, and Ag2O-SnS2 also has strong adsorption capacity to C2H2 and C2H4 molecules. This work provides a theoretical basis for the application of gas sensors used in oil-immersed transformers.

Infrared thermal inspection is the primary way to detect transmission line conductor faults. Nevertheless, the conventional inspections are carried out at low wind speeds, causing high investment and low efficiency. Besides, the relationship between wind speed and infrared image clarity of transmission lines has yet to be investigated. In this paper, a temperature difference-based definition of infrared imaging contrast that quantifies image clarity is firstly proposed. To explore the relationship between thermal imaging contrast and wind speed, thermal cycling tests are carried out. Based on tests and membership frequency research, a method for predicting whether a clear image could be obtained is derived. In addition, the accuracy of the proposed method is verified in a natural environment. The results show that wind speed is the only variable that affects infrared imaging contrast. High clarity image can be acquired when the contrast ranges from 0.35 to 0.78. Moreover, the average error between the practical and calculated values of contrast in the natural test is 9.1%, indicating that the proposed method is effective. The conclusion in this work provides feasible guiding significance for the infrared thermal imaging inspection engineering of overhead transmission lines.

Air gap impulse discharge characteristics of railway tunnel‐catenary at high‐altitude are of great significance to the electrical insulation design. The existing altitude correction methods for non‐uniform air gaps are not applicable to tunnel‐catenary. To investigate the impulse discharge characteristics of the tunnel‐catenary, a typical structural model was built in an artificial climate chamber. Different altitudes were simulated by adjusting the atmospheric pressure. The 50% breakdown voltages of the 300–700 mm tunnel‐catenary gap were tested at 243–4000 m. The test found that the altitude/atmospheric pressure and gap length have an evident effect on the 50% impulse breakdown voltage, and the influence of humidity is relatively small. The polarity effect was analysed by streamer theory. The { d , P , h } parameter method was employed to obtain the fitting formulas for the impulse breakdown voltage. A high‐altitude correction method for the tunnel‐catenary breakdown voltage based on 1 km altitude was proposed. Field natural tests were conducted to verify the accuracy of the proposed method. The results show that the breakdown voltage obtained by the correction method has an average error of 3.66% in the results of the field tests, indicating that the method has engineering application prospects.

This paper calculates and analyzes the collision and freezing characteristics of water droplets on the cylindrical conductors with different diameters and deduces the variation law of icing weight change rate on different diameters rotating cylindrical conductors with wind speed, ambient temperature, liquid water content, and median volume diameter. Then, a prediction and value-seeking method of icing environment parameters based on rotating circular conductors is determined. The laboratory test results show that the measured values of ambient temperature T, wind speed U, liquid water content w and median volume diameter MVD are in good conformity with the reference values measured by other instruments, and the average errors of each parameter are 3.41%, 5.44%, 6.08% and 7.20%, respectively. The field natural experiment was carried out at Hunan Xuefengshan Energy Equipment Safety National Observation and Research Station. The obtained icing environmental parameters were substituted into the icing simulation calculation model of the LDQ-100 glass insulator. Compared with the field experiment results, the simulated ice shape and the field ice shape were in good agreement. The error between the numerical calculation results of the icing weight and the field icing weight of the experimental insulator was less than 6%.

Water plays an indispensable role in various fields, encompassing industry, daily life, and atmospheric environment monitoring. The increasing scarcity of water resources and the associated risks posed by icing have gained significant attention. This study presents a novel approach by proposing the modification of SnS monolayer utilizing transition metal oxides (TMOs, CrO, NiO, CuO) to enhance H ₂ O adsorption. Through density functional theory, this investigation systematically explores the interaction mechanism, electronic properties, -and sensing behavior of H ₂ O when interacting with transition metal oxides doped with tin sulfide (TMOs-SnS). The TMOs particles exhibit substantial modification capabilities, with adsorption distance reduced by 21.06% (CrO-SnS), 35.52% (NiO-SnS), and 61.31% (CuO-SnS), respectively, compared to pure SnS. Specifically, CrO-SnS and NiO-SnS demonstrate physical adsorption behavior towards H2O, while H ₂ O/CuO-SnS exhibits chemical adsorption behavior characterized by an exceptionally high adsorption energy of -1.637 eV. At room temperature, TMOs-SNS demonstrates excellent desorption performance with a resolution of CrO-SnS > NiO-SnS > CuO-SnS. In theory, TMOs-SnS good the potential for application in the H ₂ O adsorption and atmospheric icing monitoring.

The adoption of online and offline collaborative teaching between Chinese and foreign teachers for foreign courses in China and Foreign Countries’ Joint Higher Education program is an innovation in the international teaching model. It has played an important role in promoting international education. However, due to the short practice time, how to effectively carry out this teaching model has become a new topic. This paper analyzes the difficulties and challenges faced by this model in teaching implementation. Finally, suggestions are given to improve the teaching effectiveness from the perspectives of the university and teacher.