Isabella quarter is without distinction". The "American Journal of Numismatics" had other criticisms of the quarter: Minting of what Barber dubbed "showy quarters" began at the Philadelphia Mint on June 13, 1893, six weeks after the exposition opened. Leech had planned to strike the pieces using polished blanks, or planchets, and workers at that mint handled the coins carefully; unlike the half dollar, surviving specimens display relatively few contact marks from other coins. The first piece struck, along with numbers 400, 1,492, and 1,892, were struck in proof condition and sent to the Lady Managers along with certificates attesting to their status.
Metal-insulator-metal Metal-insulator-metal Metal-insulator-metal (MIM) diode is a type of nonlinear device very similar to a semiconductor diode that is capable of very fast operation. Depending on the geometry and the material used for fabrication, the operation mechanisms are governed either by quantum tunnelling or thermal activation. In 1948, Torrey et al. stated that "It should be possible to make metal-insulator-metal rectifiers with much smaller spreading resistances than metal-semiconductor rectifiers have, consequently giving greater rectification efficiency at high frequencies". But due to fabrication difficulties, two decades passed before the first device could be successfully created. Some of the very first MIM diodes