Asymmetry the easy way
Article Abstract:
Symmetry pervades nature from the atomic scale to the macroscopic. Self assembled systems usually form with a point, line or plane of symmetry, and the tendency towards symmetric structures is the bane of self-assembled systems. Stadler and colleagues have developed a novel approach to producing a self-assembling material that forms a non-centrosymmetric layered nanostructure. Subtle macromolecular interactions produced a self-assembling asymmetric structure, blended from two block copolymer materials.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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The hard problem of carbonitrides
Article Abstract:
The elastic properties of carbonitrides, which are connected with their hardness, can be explained by the filling of electron states according to whether the underlying lattice is occupied by transition-metal or carbon and nitrogen atoms, or by vacancies. There is competition between the filling of a set of states conducive to elastic strength and a set of states with the opposite effect. The competition leads to a maximum in elastic constants as a function of electron filling.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Measures of crystal vacancies
Article Abstract:
Crystal vacancies are central to solid-state physics and metallurgy. Schaefer and colleagues have shown how the time variation in a crystal can be determined at differing temperatures. They have used an improved version of the volume comparison method, using an incremental Michelson laser interferometer. Both rate and magnitude of change in vacancy concentration in FeA1 and NiA1 intermetallics were measured.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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