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
Graphite is a form of carbon. Graphite is silvery black with a dull metallic luster. Graphite is a mineral that is very soft. On the Mohs hardness scale, it falls between 1 and 2. Because of this softness and tendency to flake, it works very well as a dry lubricant.raphite is silvery black with a dull metallic luster. Graphite is a mineral that is very soft. On the Mohs hardness scale, it falls between 1 and 2. Because of this softness and tendency to flake, it works very well as a dry lubricant.