Abstract:
In material science, size of the systeM.S. is an important parameter, and commonly used terM.S. are
nano, micro, meso and macro where the characteristic length is 10-9, 10-6, 10-4 and 10-2 meters
respectively. In some sense, every macroscopic system is made of micro/nanosysteM.S.. In daily
life, we come across many such examples. For instance, size of a butterfly is about 4 cm and the
wings comprise of micron structures separated by a submicron gap, and each microstructure is
made of nanostructures (Figs. 1.1a and b) (1). Similarly talcum powder, used in cosmetics is
made of fine nanocrystallites (Figs. 1.1c and d) (2).
