a. a usually circular and often variable opening in an optical instrument or device that controls the quantity of radiation entering or leaving it
Friday, March 25, 2011
Tuesday, March 22, 2011
Thursday, March 17, 2011
Tuesday, February 8, 2011
Monday, February 7, 2011
Sunday, February 6, 2011
Thursday, February 3, 2011
Wednesday, January 12, 2011
Subscribe to:
Posts (Atom)