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Due to the complex operating conditions and high-reliability requirements of special motors, the thermal management technology combining the heat conduction sheet in the slot and the heat absorption of phase change materials outside the slot is used to restrain the winding temperature rise. In this paper, an optimized stator structure is proposed, and the temperature rise analysis model of winding in the slot is established. On the premise that the electromagnetic performance remains unchanged, the temperature rise suppression method of rapid heat transfer in the slot and rapid heat absorption outside the slot is adopted to study and analyze the suppression effect of winding temperature rise under different working conditions.

The global spread of COVID-19 has led to a massive increase in public demand for effective measures to slow the spread of the virus. In response, the World Health Organization has advised people to wear face masks every day to stop the spread of the virus. In facial mask recognition, traditional manual feature extraction methods are cumbersome and inaccurate, considering the various types of masks and other practical problems. This paper considers various neural network models comprehensively and selects three classical CNN networks, including VGG, ResNet, and DenseNet. After using the data expansion and optimization methods, good data results are obtained for the three network models. Remarkably, the improved DenseNet accuracy can reach 99.55%.

In order to reduce the implementation cost of building insulation, and more flexible to meet the needs of building regulation, we need to actively find new methods to carry out the research of building thermal model. Based on this, this paper first analyses the principle and organization of building natural ventilation, then studies the coupling simulation of natural ventilation and building thermal model, and finally gives the result analysis of the coupling simulation of natural ventilation and building thermal model.

Through the observation of the microstructure of the longitudinal and transverse sections of the tibia, it is found that the distribution of mineralized collagen fibers is layered. There are many biological micropores in the cross section of the tibia, and the mineralized collagen fibers near the pores bypass the pores in an orderly manner, thereby forming a mineralized collagen fiber circuitous hole structure. According to the observation results, a finite element analysis model of fiber reinforced composites with fiber circuitous hole structure and drilling hole structure is established. The analysis results show that the maximum strain of the drilling hole structure and fiber circuitous hole structure are 6.428e-3 and 3.583e-3, respectively. The maximum strain of the drilling hole structure is about 1.8 times that of the fiber circuitous hole structure under the same load. The results have shown that the fiber circuitous hole structure of tibia has an excellent resistance to deformation, which can effectively improve the toughness of the tibia. The application of the structure to the composite material can effectively improve the strength of the composite material.