Obsolete Russian units of measurement Peter the Great replace it with the Hindu-Arabic numeral system. The basic unit is the Russian cubit, called the "arshin", which has been in use since the 16th century. It was standardized by Peter the Great in the 18th century to measure exactly twenty-eight English inches (). Thus, 80 vershoks = 20 piads = 5 arshins = 140 English inches (). A "piad" (, “palm”, “five”) or "chetvert" (, “quarter”) is a hand span, the distance between ends of the spread thumb and index finger. Alternative units: As in many ancient systems of measurement the Russian distinguishes between dry and
Probe tip small tips in nanoscale due to resolution limitation of the optical microscopy. In electron field emission current measurement method, a high voltage is applied between tip and another electrode followed by measuring field emission current employing Fowler-Nordheim curves formula_6. Large fields-emission current measurements may indicate that the tip is sharp and low field-emission current indicates that the tip is blunt, molten or mechanically damaged. A minimum voltage is essential to facilitate the release of electrons from the surface of tip which in turn indirectly is used to obtain the tip curvature. The downside of this method to the several advantages