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Fabrication and tribological properties of carbon fiber and copper fib by Pei Wang, Hao Song et al

To attain new pantograph skateboard with high strength-toughness and simple fabrication process, copper fiber and carbon fiber reinforced carbon-based composite (Cuf/Cf/C composite) was fabricated by hot pressing technology, micro-structure, mechanical and tribological performances were investigated and compared with the results of carbon skateboard. Cuf/Cf/C composite is superior to carbon skateboard in terms of compactness, hardness, electrical conductivity, mechanical strength and wear resistance. During sliding friction tests with electric current, mechanical acting wear and arc erosion have a stimulating circulation on the worn surface, and adding carbon fiber slows down the deteriorated wear cycle and improves wear resistance. High carbon crystallinity degree of the tribolayer presents low molecular acting friction force, and adjusting crystallite structure is essential to improve friction performance.

A (CrFeNi)83(AlTi)17 high-entropy alloy matrix solid-lubricating compo by Yushan Geng, Jun Cheng et al

High-entropy alloy matrix solid-lubricating composites (HSLCs) are promising anti-wear and friction-reduced materials to meet the demands of complicated engineering applications. Here we present a strategy to develop HSLCs by using the coupled high-entropy phases of (BCC + FCC + L21) with near-equal volume fraction as the matrix material, instead of using the usual single phase-dominated high-entropy phases, which can preserve the intrinsic strength and deformability of the matrix while activating adaptive wear protection during sliding. This enables a low coefficient of frictions of 0.23–0.31 and wear rates within the order of 10–6–10–5 mm3 N m–1 for the (CrFeNi)83(AlTi)17-Ag-BaF2/CaF2 HSLC between room-temperature and 800 °C, considerably outperforming the reported HSLCs and conventional alloy matrix solid-lubricating composites. At low and moderate temperatures, the synergistic Ag-BaF2/CaF2 lubricating films eliminate the surface stress concentration upon wear, thus suppr

Can Fear Mechanisms Aid in the Formulation of Anxiety-reducing Drugs

New target in the brain that underpins the eliciting of anxiety and fear behaviors, such as freezing, has been identified by neuroscientists.

A case study on the wear mechanism and stress evolution of graphite pl by Jun Jiang, Shanhong Wan et al

Graphite plugged bronze has been primarily applied as the self-lubricating part in the tough oilless conditions, and understanding the detailed wear characteristics and the contacting stress evolution of graphite plugged bronze was important to improve its design for the in-service reliability. This study investigated the wear characteristics and contacting stress of graphite plugged bronze sliding plate from the field trial by means of the multiple topographic characterizations and computational analysis. The results revealed that abrasive wear and adhesive wear predominated on the contacting surface of graphite plugged bronze plate, accompanied by the localized fatigue and erosion. Computational simulation well illustrated the increasingly accumulated stress at the boundary between bronze and graphite as referenced with the stress evolution of bronze matrix and graphite plug, which was considered to be the leading cause of aggravated wear over time. Finding from this study provided t

Brain Circuits for Fear Responses

Brain circuits or brain mechanisms that regulate threat/fear responses in animals have been discovered.

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