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In order to study the sound absorbing properties of activated carbon fiber felts, three kinds of activated carbon fiber felts with different densities were selected, and the double channel acoustic analyzer with impedance tube was used to test the surface acoustic impedance within 125-2 500 Hz frequency sound waves. Then the four acoustic parameters, that is the sound absorption coefficient, the characteristic impedance, the propagation constant, and the structural constant, were calculated. Finally, the effect of density on the sound absorbing properties of activated carbon fiber felts was analyzed. It was found that with the increase of the frequency, the sound absorption coefficient and the propagation constant of the sample increased, but the characteristic impedance ratio and the structural constant decreased, but the decline was smaller and tended to be stable. With the increase of the density of activated carbon fiber felts, the acoustic parameters of the samples all increased, but the first resonance frequency moved towards low frequency, and the corresponding sound absorption coefficient increased.

To solve the problem of easy abrasion of hand protection textiles, the basic principles, evaluation standards and test methods of hand protection textiles wear resistance were introduced, and the research progress of domestic and foreign textiles enhancement technologies in recent years were highlighted. On the one hand, the wear resistance of textiles was enhanced by adjusting the textile material composition and structure design, including fiber, yarn and fabric raw material selection, fiber assembly and fabric structure design, etc.; on the other hand, the wear resistance of textiles was improved by finishing, including resin coating treatment, rubber coating treatment and latex coating treatment. The analysis shows that because the composition and structural design of textiles have been difficult to meet the high wear resistance requirements of textiles, the coating treatment of textiles, especially latex coating treatment effectively enhance the wear resistance of textiles and help to the improvement of comfort and flexibility. [ABSTRACT FROM AUTHOR]