Muscle-inspired MXene/PVA hydrogel with high toughness and photothermal therapy for promoting bacteria-infected wound healing

The process of wound healing is often accompanied by bacterial infection, which is a serious threat to human health. The abuse of antibiotics in traditional therapy aggravates the resistance of...

The size effect of martensite laths and precipitates on high strength wear-resistant steels

Low alloy high strength wear resistant steels are with high toughness, low cost and good abrasion resistance. It can effectively resist the propagation of wear cracks and prolong the service life of machine components. This paper focuses on the internal relationship between macroscopic physical properties and microscopic martensite lath and precipitate size throughout thickness of wear resistant steel. Four kinds of 40mm thickness wear resistant steels with different alloy chemical composition were produced and investigated. Results show the strength and hardness performance of ARIV are obviously higher than other three steels. ARI have a relatively large strength difference through thickness. The impact toughness of ARIV is relatively uniform, which is greater than that of the ARIII at middle layer and lower than that of the ARIII at 1/4 layer. The width of martensite lath of ARIV is relatively small, mainly 100 ~ 300 nm，while that of ARII and ARIII is mainly 200 ~400 nm. ARIV steel has shorter martensite lath band and more precipitates below 50 nm. It indicates that the size of martensite laths and precipitates of wear-resistant steels are important factors to determine its performance throughout thickness.

Design of Cold-Mixed High-Toughness Ultra-Thin Asphalt Layer towards Sustainable Pavement Construction

Ultra-thin asphalt overlay has become the mainstream measure of road preventive maintenance due to its good economic benefits and road performance. However, hot mix asphalt concrete technology is widely used at present, which is not the most ideal way to promote energy saving and emission reduction in the field of road maintenance. At the same time, the ultra-thin friction course based on cold mix technology, such as slurry seal layer, micro-surface, and other technologies, are still far behind the hot mix friction course in terms of crack resistance. In this research, by establishing an integrated design of materials and structures, a cold paving technology called “high-toughness cold-mixed ultra-thin pavement (HCUP)” is proposed. The high-viscosity emulsified bitumen prepared by using high-viscosity and high-elasticity modified bitumen is used as the binder and sticky layer of HCUP. The thickness of HCUP is 0.8–2.0 cm, the typical thickness is 1.2 cm, and the nominal maximum size of the coarse aggregate is 8 mm. Indoor tests show that HCUP-8 has water stability, anti-skid performance, high temperature performance, peeling resistance, and crack resistance that are not weaker than traditional hot-mixed ultra-thin wear layers such as AC-10, Novachip, and GT-8. At the same time, the test road paving further proved that HCUP-8 has excellent road performance with a view to providing new ideas for low-carbon and environmentally friendly road materials.