Ted Janssen, Gervais Chapuis, and Marc de Boissieu
- Published in print:
- 2018
- Published Online:
- August 2018
- ISBN:
- 9780198824442
- eISBN:
- 9780191863288
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198824442.003.0001
- Subject:
- Physics, Crystallography: Physics, Condensed Matter Physics / Materials
First a general description of the concept of crystalline structures is presented with some historical background information. The classical approach of periodic structures is presented along with ...
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First a general description of the concept of crystalline structures is presented with some historical background information. The classical approach of periodic structures is presented along with the important topic of symmetry and its role characterizing physical properties. The limitations of the classical model are then introduced in view of the new experimental observations discovered since the 1970s. New forms of crystalline structures including incommensurately modulated and composite structures are presented along with quasicrystalline structures (quasicrystals). The necessity to extend the theory of space group symmetry is then discussed and the concept of superspace symmetry is introduced in order to describe these new forms of matters.Less
First a general description of the concept of crystalline structures is presented with some historical background information. The classical approach of periodic structures is presented along with the important topic of symmetry and its role characterizing physical properties. The limitations of the classical model are then introduced in view of the new experimental observations discovered since the 1970s. New forms of crystalline structures including incommensurately modulated and composite structures are presented along with quasicrystalline structures (quasicrystals). The necessity to extend the theory of space group symmetry is then discussed and the concept of superspace symmetry is introduced in order to describe these new forms of matters.
Laszlo Solymar
- Published in print:
- 2021
- Published Online:
- June 2021
- ISBN:
- 9780198863007
- eISBN:
- 9780191895760
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198863007.003.0018
- Subject:
- Physics, Geophysics, Atmospheric and Environmental Physics
A history of the use of single- and multimode fibres in optic fibres is provided. Wavelength division multiplex is introduced, The same fibre can carry hundreds of wavelength bands. The longest ...
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A history of the use of single- and multimode fibres in optic fibres is provided. Wavelength division multiplex is introduced, The same fibre can carry hundreds of wavelength bands. The longest stretch of optical fibre line is about 10,000 km. The greatest capacity achieved has been in the petabit/s range for a single cable with 32 cores, each one having 16 wavelength channels capable of carrying 680 Gb/s each. The ‘last mile’ problem still has not been solved in Britain. The relative advantages of satellites and optical fibres are discussed. Fibres working on different physical principles, e.g. holey fibres, have also been invented.Less
A history of the use of single- and multimode fibres in optic fibres is provided. Wavelength division multiplex is introduced, The same fibre can carry hundreds of wavelength bands. The longest stretch of optical fibre line is about 10,000 km. The greatest capacity achieved has been in the petabit/s range for a single cable with 32 cores, each one having 16 wavelength channels capable of carrying 680 Gb/s each. The ‘last mile’ problem still has not been solved in Britain. The relative advantages of satellites and optical fibres are discussed. Fibres working on different physical principles, e.g. holey fibres, have also been invented.
