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C4F7N/CO2 gas mixtures have attracted extensive attention because of their excellent insulating properties and environmental friendliness. High electrical and thermal stability is an important indicator for evaluating their performance, but there have been few molecular dynamics studies of their decomposition mechanisms. In this study, using ReaxFF molecular dynamics simulations and quantum chemistry theory, the decomposition mechanism of a C4F7N/CO2 gas mixture and the effect of the O2 content on the decomposition of the mixture were simulated on the microscopic level. It was found that there are three main decomposition pathways of C4F7N molecules, of which the generation of C3F4N⋅ and CF3⋅ free radicals is the most likely to occur. COF2 is the main oxygen-containing product of the C4F7N/CO2 gas mixture, and its generation is significantly affected by the simulation time and temperature. COF2 can be regarded as the characteristic decomposition product of the C4F7N/CO2 gas mixture. The addition of O2 slightly promotes the decomposition of C4F7N, whereas the maximum decomposition rate of CO2 decreases by 0.3% and 1% after the addition of 2% and 8% O2, respectively. Relevant results of this research can provide a theoretical basis and guidance for research into the performance of C4F7N/CO2 gas mixtures and practical engineering applications of these mixtures in the future. [ABSTRACT FROM AUTHOR]

OBJECTIVE: We aimed to examine the effects of a 5:2 diet (2 days per week of energy restriction by formula diet) or an exercise (2 days per week of high-intensity interval training and resistance training) intervention compared with routine lifestyle education (control) on glycemic control and cardiometabolic health among adults with overweight/obesity and type 2 diabetes. RESEARCH DESIGN AND METHODS: This two-center, open-label, three-arm, parallel-group, randomized controlled trial recruited 326 participants with overweight/obesity and type 2 diabetes and randomized them into 12 weeks of diet intervention (n = 109), exercise intervention (n = 108), or lifestyle education (control) (n = 109). The primary outcome was the change of glycemic control measured as glycated hemoglobin (HbA1c) between the diet or exercise intervention groups and the control group after the 12-week intervention. RESULTS: The diet intervention significantly reduced HbA1c level (%) after the 12-week intervention (−0.72, 95% CI −0.95 to −0.48) compared with the control group (−0.37, 95% CI −0.60 to −0.15) (diet vs. control −0.34, 95% CI −0.58 to −0.11, P = 0.007). The reduction in HbA1c level in the exercise intervention group (−0.46, 95% CI −0.70 to −0.23) did not significantly differ from the control group (exercise vs. control −0.09, 95% CI −0.32 to 0.15, P = 0.47). The exercise intervention group was superior in maintaining lean body mass. Both diet and exercise interventions induced improvements in adiposity and hepatic steatosis. CONCLUSIONS: These findings suggest that the medically supervised 5:2 energy-restricted diet could provide an alternative strategy for improving glycemic control and that the exercise regimen could improve body composition, although it inadequately improved glycemic control. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) detection is essential in assessing the insulation state of electrical equipment. However, PD signals are often overwhelmed by interference, resulting in inaccurate detection results. Aiming at this problem, this study proposes a PD detection method based on singular value decomposition (SVD) and improved spectral subtraction. First, the test signal is constructed as a Hankel matrix, which is used as a trajectory matrix for the SVD. Next, the singular value mutation point in the feature matrix is set as the threshold for removing the narrowband interference (NBI), and a signal containing only white noise is obtained. Finally, the improved spectral subtraction is used to remove white noise and improve the signal‐to‐noise ratio (SNR). The method proposed herein, along with the variational mode decomposition, the empirical mode decomposition, and the improved threshold wavelet method, are applied to the processing of PD signals. Also, the SNR value, waveform similarity coefficient, and mean square error of the denoizing signal of the four algorithms were calculated, considering the noise suppression and feature preservation abilities. The simulation and measurement results show that the SVD‐spectral subtraction method has a strong suppression effect on narrow‐band interference and white noise. Compared with other algorithms, this method can significantly improve the execution efficiency and has great application prospects. [ABSTRACT FROM AUTHOR]