acoustic impedance acoustics amplifier bit bubble memory computer ddr sdram digital drum memory dynamic random access memory edvac eeprom eprom ferranti ferroelectric ram flash memory free electron laser integrated circuit klystron magnetic core memory magnetoresistive random access memory magnetostriction memory refresh monroe epic moore school of electrical engineering nano-ram nickel non-volatile memory olivetti pal phase-change memory piezoelectricity plated wire memory programmable calculator programmable metallization cell programmable read-only memory pulse repetition frequency pulse shaping racetrack memory radar radar display resistive random-access memory sonos second sequential access speed of sound static random access memory storage device surface wave transducer twin transistor ram twistor memory univac i undulator united states naval research laboratory university of pennsylvania vacuum tube volatile memory williams tube world war ii z-ram