Simulation and Study of Influencing Factors on the Solidification Microstructure of Hazelett Continuous Casting Slabs Using CAFE Model.

The Hazelett continuous casting and rolling process represents a leading-edge production method for cold-rolled aluminum sheet and strip billets in the world. Its solidification microstructure significantly influences the quality of billets produced for cold rolling of aluminum sheets and strips. In this study, employing the CAFE (Cellular Automaton-Finite Element) method, we developed a coupled computational model to simulate the solidification microstructure in the Hazelett continuous casting process. We investigated the impact of nucleation parameters, casting temperature, and continuous casting speed on the microstructural evolution of the continuous casting billet. Through integrated metallographic analyses, we aimed to elucidate the controlling mechanisms underlying the Hazelett continuous casting process and its resultant microstructure. The results demonstrate that the equiaxed rate of grains increases with an increase in nucleation density, and the grain size decreases under constant cooling strength. With other nucleation parameters held constant, the grain size decreases as undercooling increases, and the columnar crystal zone expands. The nucleation density of the Hazelett continuous casting aluminum alloy has been determined to range between 1011 m-3 and 1013 m-3, and the undercooling ranges between 1 °C and 2.5 °C. The solidified grain structure can be controlled between 35 µm and 72 µm. The grain size of the continuous casting billet increases with an increase in pouring temperature and decreases as the casting speed increases. Elevating the pouring temperature positively impacts the fraction of high-angle grain boundaries and promotes the dendritic to equiaxed grain transition. Moreover, there exists potential for further optimization of continuous casting process parameters.

Composite of CoS1.97 nanoparticles decorated CuS hollow cubes with rGO as thin film electrode for high-performance all solid flexible supercapacitors.

Stretchable flexible thin-film electrodes are extensively explored for developing new wearable energy storage devices. However, traditional carbon-based materials used in such independent electrodes have limited practical applications owing to their low energy storage capacity and energy density. To address this, a unique structure and remarkable mechanical stability thin-film flexible positive electrode comprising CoS1.97 nanoparticles decorated hollow CuS cubes and reduced graphene oxide (rGO), hereinafter referred to as CCSrGO, is prepared. Transition metal sulfide CoS1.97 and CuS shows high energy density owing to the synergistic effects of its active components. The electrode can simultaneously meet the high-energy density and safety requirements of new wearable energy storage devices. The electrode has excellent electrochemical performance (1380 F/g at 1 A/g) and ideal capacitance retention (93.8 % after 10,000 cycles) owing to its unique three-dimensional hollow structure and polymetallic synergies between copper and cobalt elements, which are attributed to their different energy storage mechanisms. Furthermore, a flexible asymmetric supercapacitor (FASC) was constructed using CCSrGO as the positive electrode and rGO as the negative electrode (CCSrGO//rGO), which delivers an energy density of 100 Wh kg-1 and a corresponding power density of 2663 W kg-1 within a voltage window of 0-1.5 V. The resulting FASC can power a light-emitting diode (LED) at different bending and twisting angles, exerting little effect on the capacitance. Therefore, the prepared CCSrGO//rGO FASC devices show great application prospects in energy storage.

Injectable and Thermosensitive Hydrogel with Platelet-Rich Plasma for Enhanced Biotherapy of Skin Wound Healing.

The rapid and effective healing of skin wounds resulted from severe injuries and full-layer skin defects remains a pressing clinical challenge in contemporary medical practice. The reduction of wound infection and rapid healing is helpful to rebuild and repair skin tissue. Here, a thermosensitive chitosan-based wound dressing hydrogel incorporating ß-glycerophosphate (GP), hydroxy propyl cellulose (HPC), graphene oxide (GO), and platelet-rich plasma (PRP) is developed, which exhibits the dual functions of antibacterial properties and repair promotion. GP and HPC enhance the mechanical properties through forming hydrogen bonding connection, while GO produces local heat under near-infrared light, leading to improved blood circulation and skin recovery. Notably, antibacterial properties against Pseudomonas aeruginosa, and control-release of growth factors from PRP are also achieved based on the system. In vitro experiments reveal its biocompatibility, and ability to promote cell proliferation and migration. Animal experiments demonstrate that the epithelial repair and collagen deposition can be promoted during skin wound healing in Sprague Dawley rats. Moreover, a reduction in wound inflammation levels and the improvement of wound microenvironment are observed, collectively fostering effective wound healing. Therefore, the composite hydrogel system incorporated with GO and PRP can be a promising dressing for the treatment of skin wounds.