Supercapacitor
Since capacitors' energy content increases with the square of the voltage, researchers were looking for a way to increase the electrolyte's breakdown voltage. In 1994 using the anode of a 200V high voltage tantalum electrolytic capacitor, David A. Evans developed an "Electrolytic-Hybrid Electrochemical Capacitor". These capacitors combine features of electrolytic and electrochemical capacitors. They combine the high dielectric strength of an anode from an electrolytic capacitor with the high capacitance of a pseudocapacitive metal oxide (ruthenium (IV) oxide) cathode from an electrochemical capacitor, yielding a hybrid electrochemical capacitor. Evans' capacitors, coined Capattery, had an energy content about a factor of 5 higher than a comparable tantalum electrolytic capacitor of the same size. Their high costs limited them to specific military applications.
Bell Labs
In 1947, the transistor, probably the most important invention developed by Bell Laboratories, was invented by John Bardeen, Walter Houser Brattain, and William Bradford Shockley (and who subsequently shared the Nobel Prize in Physics in 1956). In 1947, Richard Hamming invented Hamming codes for error detection and correction. For patent reasons, the result was not published until 1950. In 1948, "A Mathematical Theory of Communication", one of the founding works in information theory, was published by Claude Shannon in the "Bell System Technical Journal". It built in part on earlier work in the field by Bell researchers Harry Nyquist and Ralph Hartley, but it greatly extended these. Bell Labs also introduced a series of increasingly complex calculators through the decade. Shannon was also the founder of modern cryptography with his 1949 paper "Communication Theory of Secrecy Systems".In 1952, William Gardner Pfann revealed the method of zone melting which enabled semiconductor purification and level doping.