Electric current certain materials when cooled below a characteristic critical temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of "perfect conductivity" in classical physics. In a semiconductor it is sometimes useful to think of the current as due to the flow
Heike Hennig Heike Hennig Heike Hennig (born 8 November 1966) is a German dancer, choreographer and director of the opera and dance ensemble "Heike Hennig & Co". Heike Hennig had her first dance lessons at the age of 5 years in Leipzig. In 1989, through her escape from East Germany (GDR), she was able to study modern dance, choreography and Body-Mind Centering (BMC) in Cologne and at Moving on Center – School for Participatory Arts and Research in Oakland, California; she then studied in the US with teachers such as Steve Paxton. Following that, Heike Hennig worked in Brazil and Portugal. In