SI base unit SI base unit The International System of Units (SI) defines seven units of measure as a basic set from which all other SI units can be derived. The SI base units and their physical quantities are the meter for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance. The SI base units form a set of mutually independent dimensions as required by dimensional analysis commonly employed in science and technology. The names and symbols of SI base
Lee Si-Chen Lee Si-Chen Lee Si-Chen (; born August 13, 1952 in Gangshan (岡山), Taiwan), is a Taiwanese engineer specializing in semiconductors, a researcher in amorphous silicon in the early development in Taiwan, and an IEEE Fellow. He has been a professor of electrical engineering since 1982 and the president of National Taiwan University from 2005 to 2013. He received a bachelor's degree in electrical engineering from National Taiwan University (1974) and a master's degree (1977) and PhD (1981), both in electrical engineering, from Stanford University. He is the current president of National Taiwan University (2005 – ), president of the Association