308. Q U I Z NO. 9 Supercomputer

Q U I Z   NO.  9

Supercomputer

1.      Superconductors, materials that have no resistance to the flow of electricity, are one of the last great frontiers of scientific discovery.

2.      In 1911 superconductivity was first observed in mercury by Dutch physicist Heike Kamerlingh Onnes of Leiden University.

3.      The Type 1 category of superconductors is mainly comprised of metals and metalloids that show some conductivity at room temperature.

4.      Type 1 superconductors - characterized as the "soft" superconductors - were discovered first and require the coldest temperatures to become superconductive.

5.      Copper, silver and gold, three of the best metallic conductors, do not rank among the superconductive elements.

6.      Many additional elements can be coaxed into a superconductive state with the application of high pressure.

7.      The periodic table below for all known elemental superconductors (including Niobium, Technetium and Vanadium which are technically Type 2).

8.      When he cooled it to the temperature of liquid helium, 4 degrees Kelvin (-452F, -269C), its resistance suddenly disappeared.

9.      In a superconductor the induced currents exactly mirror the field that would have otherwise penetrated the superconducting material - causing the magnet to be repulsed.

10.  This phenomenon is known as strong diamagnetism and is today often referred to as the "Meissner effect"

11.  In 1941 niobium-nitride was found to superconduct at 16 K.

12.  In 1953 vanadium-silicon displayed superconductive properties at 17.5 K.

13.  in 1962 scientists at Westinghouse developed the first commercial superconducting wire, an alloy of niobium and titanium (NbTi).

14.  High-energy, particle-accelerator electromagnets made of copper-clad niobium-titanium were then developed in the 1960s

15.  first employed in a superconducting accelerator at the Fermilab Tevatron in the US in 1987.

16.  Theories of Superconductivity became know as the BCS theory

17.  BCS stands for Bardeen, Cooper, Schrieffer who won Nobel prize.

18.  electrical current would flow between 2 superconducting materials - even when they are separated by a non-superconductor or insulator.

19.  Brian D. Josephson (above), a graduate student at Cambridge University, predicted that

20.  electrical current would flow between 2 superconducting materials - even when they are separated by a non-superconductor or insulator.

21.  The 1980's were a decade of unrivaled discovery in the field of superconductivity.

22.  In 1964 Bill Little of Stanford University had suggested the possibility of organic (carbon-based) superconductors.

23.  Magnetic Resonance Imaging (MRI) was actually discovered in the mid 1940's.

24.  The first company to capitalize on high-temperature superconductors was Illinois Superconductor, formed in 1989.

25.  As if ceramic superconductors were not strange enough, even more mysterious superconducting systems have been discovered. One is based on compounds centered around the "Fullerene".

26.  In 1993 researchers at the State University of New York at Buffalo reported Tc's between 60 K and 70 K for C-60 doped with the interhalogen compound ICl.

27.  Larger, non-spherical pure carbon fullerenes that will superconduct have only recently been discovered.

28.  In April of 2001, Chinese researchers at Hong Kong University found 1-dimensional superconductivity in single-walled carbon nanotubes at around 15 Kelvin.

29.  In February 2006, Physicists in Japan showed non-aligned, multi-walled carbon nanotubes were superconductive at temperatures as high as 12 K.

30.  Silicon-based fullerides like Na₂Ba₆Si₄₆ will also superconduct.

31.  However, they are structured as infinite networks, rather than discrete molecules.

32.  Organic superconductors are composed of an electron donor and an electron acceptor

33.  (TMTSF)₂ClO₄ [tetramethyltetraselenafulvalene + acceptor]

34.  the first high-temperature superconductor that does NOT contain any copper

35.  Laboratory testing has found MgB₂ will outperform NbTi and Nb₃Sn wires in high magnetic field applications like MRI.

36.  The most recent "family" of superconductors to be discovered is the "pnictides".

37.  Researchers do agree on one thing: discovery in the field of superconductivity is as much serendipity as it is science. Stay tuned!

38.  the Type 2 category of superconductors is comprised of metallic compounds and alloys.

39.  "perovskites" (metal-oxide ceramics that normally have a ratio of 2 metal atoms to every 3 oxygen atoms)

40.  the highest Tc overall is 254K

41.  The first superconducting Type 2 compound, an alloy of lead and bismuth, was fabricated in 1930 by W. de Haas and J. Voogd.

42.  The "Heavy Fermions" sound like a family of overweight circus performers.

43.  Doctors need a non-invasive means of determining what's going on inside the human body.

44.  (BETS)₂GaCl₄ [bis(ethylenedithio)tetraselenafulvalene + acceptor]

45.  (BEDO-TTF)₂ReO₄H₂O [bis(ethylenedioxy)tetrathiafulvalene + acceptor]

46.        "Organic" superconductors are part of the organic conductor family which includes: molecular salts, polymers and pure carbon systems (including carbon nanotubes and C₆₀ compounds).

47.  "Borocarbides" are one of the least-understood superconductor systems of all.

48.  It has always been assumed that superconductors cannot be formed from ferromagnetic transition metals - like iron, cobalt or nickel.

49.  To date only one superconductor has been found that has zero resistance at a single temperature - the opposite of reentrant superconductivity.

50.  UGe₂ and URhGe₂ exhibit simultaneous ferromagnetism and superconductivity.

51.  "Ruthenates" shortly after that SrRuO and SrYRuO₆ were also found to superconduct at similarly low temperatures.

52.  Fluoroargentates bear a strong similarity to oxocuprates, compounds that currently have the highest transition temperatures of all known superconductors.