noun, Biology. 1. an orientation of an organism to an external stimulus, as light, especially by growth rather than by movement. Origin of tropism. 1895-1900. First recorded in 1895-1900; independent use of -tropism. Related forms. tropismatic.
Friction on as-grown graphene (Fig. 1c) is ultra-low and rather uniform with its magnitude close to the previous reports4. In contrast, friction on graphene after ï¬uorination becomes
The stable and low friction coefficients of GNECN coatings were attributed to the formation of a homogeneous tribofilm on the mating ball surface together with the generation and evolution of the nano-size graphene structure in the GNECN coating.