Perfect crystals never occur in practice; imperfections, and even entire amorphous material inclusions, can and do simply get " frozen in " at low temperatures, so transitions to more stable states do not occur.
42.
A perfect crystal lattice, with low enough thermal motion and no deviations from periodic structure, would have no resistivity, but a real metal has crystallographic defects, impurities, multiple isotopes, and thermal motion of the atoms.
43.
If the system is composed of one-billion atoms, all alike, and lie within the matrix of a perfect crystal, the number of permutations of one-billion identical things taken one-billion at a time is ? = 1.
44.
Beginning in 1974, together with colleagues in the department, he discovered the existence of a fundamental loss mechanism for electromagnetic waves in perfect crystals, dielectrics, thereby creating dielectric microwave resonators in sapphire with Q > 10 9.
45.
A perfect crystal is one in which the internal substances that exist in two ( or more ) stable crystalline forms, such as diamond and graphite for carbon, there is a kind of " chemical degeneracy ".
46.
Except for the Al Li Cu system, all the stable quasicrystals are almost free of defects and disorder, as evidenced by X-ray and electron diffraction revealing peak widths as sharp as those of perfect crystals such as Si.
47.
When some of this helium-3 is removed, the superfluid transition occurs at a lower temperature, which suggests that the superflow is involved with actual fluid moving along imperfections in the crystal rather than a property of the perfect crystal.
48.
In crystallography, these effects are treated as separate from the structure factor F _ { hkl }, so separate factors for size or thermal effects are introduced into the expressions for scattered intensity, leaving the perfect crystal structure factor unchanged.
49.
For the entropy at absolute zero to be zero, the magnetic moments of a perfectly ordered crystal must themselves be perfectly ordered; from an entropic perspective, this can be considered to be part of the definition of a " perfect crystal ".
50.
Many of the claims advanced for the station _ such as the opportunity it provides to grow perfect crystals in the absence of gravity and to perform other exquisite manufacturing tasks _ have been hyped beyond reason and debunked by expert committees.
