Contemporary electronic device usage generates significant electromagnetic pollution, affecting nearby electronics and human health. Conventional shielding materials are inadequate, necessitating innovative solutions. This study developed a multilayered composite with iron(Ⅱ, Ⅲ) oxide (Fe₃O₄) nanoparticles, polythiophene (PTh) nanofiber arrays, and a gold nanolayer. The synergistic combination of magnetic nanoparticles and conductive polymer nanofiber arrays resulted in an electromagnetic interference (EMI) shielding effectiveness (SE) exceeding 30 dB in the X-band when Fe₃O₄ was used in moderate concentrations. This surpassed the EMI SE of a comparable composite prepared through a similar process but lacking Fe₃O₄ by approximately 10 dB. The enhanced EMI SE can be attributed to the magnetic nanoparticles, which introduced magnetic loss to attenuate electromagnetic radiation and improved the impedance match between the arrays and epoxy resin (EP) layers. Furthermore, the inclusion of nanoparticles enabled the material to exhibit an absorption-dominant EMI shielding mechanism, significantly reducing the secondary reflection of electromagnetic waves. Consequently, this novel eco-friendly EMI shielding composite shows promise for application in high-power electronic devices.

Severe stress concentration and bad sealing performance are encountered in a non-metallic engineering part during an interference fit assembly process. Both numerical calculation and experimental test are employed to analyze the causes resulting in the assembly failure. Based on the finite element method (FEM), commercial computational software, ANSYS, is first used to simulate the whole assembly process with different boundary conditions. By comparing simulation results of the assembly process with various boundary conditions, it is found that deformation energy and friction force contribute differently to the reaction force at varying assembly depths. In virtue of these simulation results, an improved engineering part is designed and fabricated. Experimental test results show that stress concentration and sealing performance problems are basically solved compared to those in the original model. Moreover, reaction forces calculated from numerical simulation and measured from experimental tests agree reasonably with each other during the interference fit progress. This work is beneficial to the understanding of the interference fit process in engineering application and the avoiding of part failure resulting from inappropriate design.