quasi-crystal


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quasi-crystal

[¦kwä·zē ′krist·əl]
(crystallography)
A phase of solid matter that, like a crystal, exhibits long-range orientational order and translational order but whose atoms and clusters repeat in a sequence defined by a sum of periodic functions whose periods are in an irrational ratio.
References in periodicals archive ?
It turned out that the crystalline structure of the quasi-crystal showed great resemblance to the structures Caris had created in his Polyhedral net structures in the early seventies (figure 6).
The fivefold symmetry in the quasi-crystal and the Polyhedral net structures by Caris can be compared to the fivefold symmetry in the so-called Penrose patterns (3).
The nearly 200 papers consider many aspects of the synthesis, characterization, and fundamental investigations of various metastable, nanostructured, amorphous, and glassy materials, as well as quasi-crystals and bulk glassy alloys.
Twarock and Jiri Patera of the University of Montreal had previously devised mathematical models for constructing certain quasi-crystals.
This gain in efficiency will be of particular interest to researchers for the determination of inorganic/organomettalic crystal structure, study of incommensurates and quasi-crystals, and powder anaylsis.
The articles cover a broad spectrum of topics including high-pressure crystallography, magnetic structure determinations, quasi-crystals, novel biomaterials, biological minerals, structure determination via neutron and x-ray diffraction, reduced cells, standard reference materials, phase equilibria and ceramic oxides, crystallographic texture, zeolitic materials, near perfect crystals, electron diffraction, crystallographic databases, protein crystallography, crystallography in construction, and synchrotron radiation.
For example, the article on quasi-crystals strikes at the fundamental definition of a crystal lattice.
In his search for a design inventory which is free of human preconceptions, Eisenman has married Form Z Macintosh software to natural phenomena such as waves, quasi-crystals and slime moulds, all of which, in his terms, have no a priori knowledge or contingencies.
Of the theoretical hypotheses brought forward so far to explain the occurrence of the quasi-crystals mentioned above some are of special importance, namely the ones suggesting the possibility of a gradual transition between the even-numbered dimensions, or, to put it differently, the ones implying that our reality is of a hyper-dimensional nature.
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