| 词汇 | quasicrystal |
| 释义 | quasicrystal noun[ C ] chemistry specializeduk /kweɪ.zaɪˈkrɪs.təl/ us /kweɪ.zaɪˈkrɪs.təl/ a solid substance with a structure that contains patterns and repetition but is not fully symmetrical (= exactly matching) like a crystal准晶体 Geology: mineralogy beneficiation crude crystal crystalline deposit gemologist gemology gold dust graphite idiomorphic intercrystalline magnesium mineral pyrite seam silicon unmined vermiculite vulcanicity zircon Examples of quasicrystalquasicrystal In other words, we view a fully periodic set, or 'crystal', as a special kind of 'quasicrystal'. One of the commonly used definitions of a quasicrystal is that of an atomic structure which has a discrete component in its diffraction spectrum. In particular, they can be viewed as a mathematical abstraction of the set of atomic positions of a physical quasicrystal (at zero temperature, or at a given instant of time). Does there exist a nice characterization of the 'simplest' aperiodic sets, which might be used to define a notion of 'perfectly ordered quasicrystal'? This natural quasicrystal exhibits high crystalline quality, equalling the best artificial examples. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Its underlying symmetry is also fivefold but it is not a quasicrystal. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Glotzer and collaborators also hold the record for the densest tetrahedron packing and discovered that hard tetrahedrons can self-assemble into a dodecagonal quasicrystal. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. It forms an aperiodic pattern known as a quasicrystal. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In order that the quasicrystal itself be aperiodic, this slice must avoid any lattice plane of the higher-dimensional lattice. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Using mathematics for construction and analysis of quasicrystal structures is a difficult task for most experimentalists. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. For a periodic quasicrystal approximant with an 82-tetrahedron unit cell, they obtained a packing density as high as 85.03%. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Recently, he has helped develop a photonic quasicrystal (the quasicrystal analogue of a photonic crystal) for efficiently trapping and manipulating light in selected wavebands. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. For a periodic crystal (as opposed to a quasicrystal), the group must also be consistent with maintenance of the three-dimensional translational symmetry that defines crystallinity. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. They are remarkable by containing micrometre-sized grains of icosahedrite, a naturally occurring quasicrystal aperiodic, yet ordered structure. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Its discovery followed a 10-year-long systematic search by scientists to find the first natural quasicrystal. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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