Anomalously persistent p-type behavior of WSe2 field-effect transistors by oxidized edge-induced Fermi-level pinning

A technique to form the edge contact in two-dimensional (2D) based field-effect transistors (FETs) has been intensively studied for the purpose of achieving high mobility and also recently overcoming the...

Measurement of moment coupling in fretting fatigue experiments

Moment coupling in fretting fatigue experiments refers to the generation of moments when a shear force is applied, caused by the difficulty in designing fretting fatigue experiments where the shear is reacted out on the same plane as the contact. Digital Image Correlation is used to measure the effect of moment coupling, and a model is created to calculate the effect of the applied moment at any point during a loading cycle on near-edge contact properties. The effects of the changing contact pressure on the slip zone sizes are considered. Finally, the model derived is used to find a load cycle including the effect of normal contact force that creates a truly constant near-edge contact pressure distribution at one edge of the flat and rounded pad. Although the calibrations found in this paper are valid only for the specific rig and specimen geometry used in this paper, the method could be readily applied to other experiments.

Tool Profile Modification of Hypoid Gear Machined by Duplex Helical Method

For the hypoid gear pair of the heavy-duty vehicle drive axle machined by the duplex helical method, in order to avoid edge contact and stress concentration on the tooth surface, a four-segment tool profile is designed to modify the concave and convex surfaces simultaneously. First, the geometric model of the four-segment tool profile is established. Second, the mathematical model of the duplex helical method based on the four-segment tool profile is established, and the method of solving the tooth surface generated by the connecting points of the four-segment tool profile is given. Finally, the finite element method of loaded tooth contact analysis is used to analyze the meshing performance of the gear pair obtained by the four-segment tool profile modification, and the results are compared with the original gear pair. The results show that after the tooth surfaces are modified, the edge contact of the tooth surfaces are avoided, the stress distribution of the tooth surfaces are improved, the maximum contact stress of the tooth surfaces are reduced, and the fatigue and wear life of the tooth surface are improved.