Vocabulary for fuzzy symmetry
Article Abstract:
Exact symmetry fits into an outmoded mechanical model of molecular structure and may be replaced by a newly developed system of continuous symmetry measures. Continuous symmetry is a measure of degrees of deviation from a rotational or mirror symmetry. In two-dimensional cases, the measure is easily determined by comparison of a structure with its images in a hypothetical symmetrized set representing the nearest object with the desired symmetry. The situation is more complex in three-space. These measures should be of use in parametrizing property surfaces in anisotropic non-equilibrium geometries.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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Thinly veiled promise
Article Abstract:
The charge density wave behavior of ultra-thin films of lead adsorbed on germanium is accompanied by metal-nonmetal transition and periodic lattice distortion. The structural symmetry of the system is broken and the molecular orbits degenerate so that an electron can occupy a lower energy level. The lead-germanium system is non-metallic in the low temperature, distorted phase due to the band gap. This behavior can be used to produce specific electronic characteristics by tailoring interface and surface properties.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Secrets of successful stone-skipping
Article Abstract:
The physics of skipping stone across water is analyzed. By monitoring the collision of a spinning disc, it is discovered that an angle of about 20 degrees between the stone and the water's surface is optimal with respect to the throwing condition yield maximum number of bounces.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2004
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