Superconducting magnet issues "shaken" out of them, until they are eventually able to operate reliably at their full planned current without experiencing quenches. Although the idea of making electromagnets with superconducting wire was proposed by Heike Kamerlingh Onnes shortly after he discovered superconductivity in 1911, a practical superconducting electromagnet had to await the discovery of superconducting materials that could support large critical supercurrent densities in high magnetic fields. The first successful superconducting magnet was built by G.B. Yntema in 1955 using niobium wire and achieved a field of 0.7 T at 4.2 K. Then, in 1961, J.E. Kunzler, E. Buehler, F.S.L. Hsu,
Heike Kemmer breeding stable for Hanoverian horses now run by Heike. In the 1990s, Heike became the farm manager, and moved the focus of the stables from show jumping to dressage. Kemmer attended her first Olympics in 2000, as an alternate to the German team, but did not participate in the Games. In 2004, she rode in the Olympics for the first time, placing 26th individually. She also rode as part of the gold-medal winning German team, but as the lowest-scoring member, her score was not used to determine the team's standing. At the 2008 Summer Olympics, her performance improved significantly, and