To investigate the relationship between surface electromyography and subjective assessment of muscle fatigue, 20 young male volunteers participated in the experiment of pistol holding and aiming. sE MG of the anterior...To investigate the relationship between surface electromyography and subjective assessment of muscle fatigue, 20 young male volunteers participated in the experiment of pistol holding and aiming. sE MG of the anterior deltoid was recorded during the entire process, while fatigue assessments(Borg scale) were collected every 30 s. We divided the signal into several parts and then octave band method was used to calculate mean energy of each part, an equation was derived based on the relationship between the mean energy of sE MG and Borg scale. The results showed that the degree of local muscle fatigue could be described by a cubic curve, and could be used to evaluate and monitor muscle fatigue.展开更多
Twin boundaries（TBs） are key factors influencing the mechanical properties of crystalline materials. We have investigated the intrinsic fatigue cracking mechanisms of TBs during the past decade. The effects of TB or...Twin boundaries（TBs） are key factors influencing the mechanical properties of crystalline materials. We have investigated the intrinsic fatigue cracking mechanisms of TBs during the past decade. The effects of TB orientations on the fatigue cracking mechanisms were revealed via cyclic deformation of a series of grown Cu bicrystals with a sole TB. Furthermore, the combined effects of crystallographic orientation and stacking fault energy（SFE） on the fatigue cracking mechanisms were clarified through cyclic deformation of polycrystalline Cu and Cu alloys. Both developments were reviewed in this report which will provide implications to optimize the interfacial design for the improvement of fatigue performance of metallic materials.展开更多
基金The Opening Foundation of the Science and Technology on Human Factors Engineering Laboratory,Chinese Astronaut Research and Training Centergrant number:HF2011-K-04
文摘To investigate the relationship between surface electromyography and subjective assessment of muscle fatigue, 20 young male volunteers participated in the experiment of pistol holding and aiming. sE MG of the anterior deltoid was recorded during the entire process, while fatigue assessments(Borg scale) were collected every 30 s. We divided the signal into several parts and then octave band method was used to calculate mean energy of each part, an equation was derived based on the relationship between the mean energy of sE MG and Borg scale. The results showed that the degree of local muscle fatigue could be described by a cubic curve, and could be used to evaluate and monitor muscle fatigue.
基金supported by the National Natural Science Foundation of China (NSFC) under Grant Nos. 51471170, 51501197 and 51571198
文摘Twin boundaries（TBs） are key factors influencing the mechanical properties of crystalline materials. We have investigated the intrinsic fatigue cracking mechanisms of TBs during the past decade. The effects of TB orientations on the fatigue cracking mechanisms were revealed via cyclic deformation of a series of grown Cu bicrystals with a sole TB. Furthermore, the combined effects of crystallographic orientation and stacking fault energy（SFE） on the fatigue cracking mechanisms were clarified through cyclic deformation of polycrystalline Cu and Cu alloys. Both developments were reviewed in this report which will provide implications to optimize the interfacial design for the improvement of fatigue performance of metallic materials.
