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Glossary
The following glossary terms were
selected from the Glossary section of the book: Stwertka,
Albert, Superconductors: The Irresistible Future,
(1991).
- absolute zero:
The theoretical limit to how cold any given
system can be. It is the point that all atomic
and molecular motion ceases.
- atom:
The smallest unit of any pure substance. All
matter is made up of different kinds of atoms. An
atom itself is made up of smaller parcticles,
such as protons, neutrons, and electrons.
- BCS theory:
A theory that explains superconductivity in terms
of bound electron pairs that are formed by the
interaction of the electrons with a metal
lattice.
- ceramic:
An earthenware product made by firing clay. A
ceramic is usually a poor conductor of
electricity.
- Cooper pairs:
A pair of electrons that somehow experience an
attractive force and are coupled together. They
are central to the BCS theory and are thought to
be carriers of electric current in a
superconductor.
- critical magnetic
field: The strength of the
magnetic field at which superconductivity
completely disappears.
- critical
temperature: The temperature
below in which certain elements become
superconductive.
- electrical
resistance: During the flow of
electricity through a conductor, the loss of
electrical energy caused by the collision of
electrons with lattice atoms.
- ion:
An atom with either an excess or deficiency of
electrons, and therefore an electric charge.
- Josephson junction:
A superfast switch used in many computers. It
consists of a thin layer of insulating material
sandwiched between layers of superconducting
material.
- Joule-Thompson:
The name given to the temperature drop that
accompanies the throttling process.
- Kelvin scale:
A temperature scale using the same degrees as the
Celsius scale but with zero defined as absolute
zero. Kelvin is the scale used almost universally
in scientific work.
- maglev (magnetic
levitation): Electromagnets
attached to a moving train that induce magnetic
fields in the tracks and support, or levitate,
the train.
- magnetic resonance
imaging (MRI): An important tool
to diagnose medical disorders that uses radio
waves and magnetic fields to probe the chemical
makeup of tissue inside the body.
- Meissner effect:
The expulsion of all magnetic fields from the
interior of a superconductor.
- 1-2-3 compound:
A superconducting ceramic with the approximate
composition YBa2Cu3O7, so
called for its relative atomic proportions of
yttrium, barium, and copper.
- superconducting
magnetic storage (SMES): A large
underground loop of superconducting cable used to
store large amounts of electrical energy.
- superconducting
quantum interference device (SQUID):
A device used to detect extremely small magnetic
fields.
- superconductivity:
The loss in some materials of all electrical
resistance at supercold temperatures.
- temperature:
A measure of the average energy of a system of
atoms.
- throttling process:
The temperature drop that accompanies the process
in which liquid or gas at high pressure seeps
through a tiny opening into a region of low
pressure.
- type II
superconductors: A group of
superconductors with large magnetic fields. An
important member of this group is the
niobium-germanium alloy Nb3Ge.
 
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"Superconductivity
is perhaps the most remarkable physical property in the
universe"
- David Pines, University of Illinois Urbana-Champaign
Center for Advanced Study Professor of physics and
electrical and computing engineering
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