Dmi 8c

The Vickers hardness of the well-polished samples with a thickness of ~0.1 cm were performed under a load of 4.9033 N for 15 s using a Vickers diamond indenter (FALCON 507, INNOVATEST, the Netherlands) and recorded through a metallurgical microscope (DMi 8C, Leica, Germany).

The micro-morphology of the grinding ball’s wear surface after high-temperature wear was characterized using metallographic electron microscopy (DMi8C, Leica, Wetzlar, Germany). The cross-sectional and surface morphology of the aluminum powder coated with reduced graphene oxide and the composite coating were characterized using a field emission scanning electron microscope (SU8010, Hitachi, Tokyo, Japan). The phase composition of the reduced graphene oxide-coated aluminum powder and composite coating was analyzed using an X-ray diffractometer (D/max-γA10, Rigaku, Tokyo, Japan). The hardness values of the composite coatings were measured using a Vickers microhardness tester (MVK-H3, Akashi, Tokyo, Japan). Five points were measured at different locations on each sample, and the average value was calculated. Raman spectroscopy (LabRam HR800, Horiba, Tokyo, Japan,) was used to characterize the reduced graphene oxide (rGO)-coated aluminum powder and the wear debris from the ball milling process. The high-temperature sliding wear properties of the coatings were studied using an high-temperature friction and wear tester (MMU-5G, Hengxu, Xi’an, China). The cross-sectional area of the wear scars was measured using an laser confocal microscope (OLS4000, Olympus, Tokyo, Japan), and the wear rate was calculated.

When the plated cells reached 70–80% confluency, Lipofectamine 3,000 (Invitrogen, United States) would be used to transiently transfected the plasmid according to the manufacturer’s protocol. The transfected cells were harvested after 48 h using trypsin. With HEK293FT-411cells, the fluorescence of EGFP was measured by fluorescent microscope (Leica DMi8 C, Germany) and RT-qPCR (LightCycler^® 480 II, Roche, Switzerland). With HEK293T cells, their genomic DNA was extracted and the editing efficiency of related genes was measured by PCR and T7 endonuclease I assay.