Quasicrystal - Revision history

BrianMcMahon: Tidied translations.

2017-11-17T10:15:10Z

Tidied translations.

BrianMcMahon: Style edits to align with printed edition

2017-05-16T13:45:33Z

Style edits to align with printed edition

MassimoNespolo: languages

2016-04-14T11:41:33Z

languages

MassimoNespolo: cat

2015-02-26T07:53:42Z

cat

MassimoNespolo: It, Ja

2012-02-08T08:35:33Z

It, Ja

BrianMcMahon at 17:26, 7 February 2012

2012-02-07T17:26:33Z

TedJanssen at 15:51, 18 May 2009

2009-05-18T15:51:00Z

TedJanssen at 14:42, 18 May 2009

2009-05-18T14:42:19Z

New page

[[Quasicrystal]]

Quasicristal (Fr.)

'''Definition'''

There are two definitions of the notion of quasicrystal.

* 1) A ''quasicrystal'' is an aperiodic crystal that is not an incommensurate
modulated structure, nor an aperiodic composite crystal. Often, quasicrystals have
crystallographically 'forbidden' symmetries. These are rotations of order different from 1, 2, 3, 4 and 6. In three dimensions a lattice periodic structure may only have rotation symmetry
of an order equal to one of these numbers. However, presence of such a forbidden symmetry
is not required for a quasicrystal. A system with crystallographically allowed rotation symmetry that is
locally similar to one with forbidden symmetries is also a quasicrystal.

* 2) The term ''quasicrystal'' stems from the property of quasiperiodicity
observed for the first alloys found with forbidden symmetries. Therefore,
the alternative definition is: a ''quasicrystal'' is an aperiodic crystal with diffraction
peaks that may be indexed by ''n'' integral indices, where ''n'' is a finite number, larger
than the dimension of the space (in general). This definition is similar to that of [[aperiodic crystal]].

'''See also''': Aperiodic crystal.

← Older revision		Revision as of 10:15, 17 November 2017
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−	<~~Font~~ color="blue">Quasicristal</font> (''Fr''). <~~Font~~ color="red">Quasikristall</font> (''Ge''). <~~Font~~ color="~~green~~">~~Cuasicristal~~</font> (''Sp''). <~~Font~~ color="~~black~~">~~Quasicristallo~~</font> (''It''). <~~Font~~ color="brown">Квазикристалл</font> (''Ru''). <~~Font~~ color="~~purple~~">~~準結晶~~</font> (''Ja'').	+	<font color="blue">Quasicristal</font> (''Fr''). <font color="red">Quasikristall</font> (''Ge''). <font color="black">Quasicristallo</font> (''It''). <font color="purple">準結晶</font> (''Ja''). <font color="brown">Квазикристалл</font> (''Ru''). <font color="green">Cuasicristal</font> (''Sp'').

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-<Font color="blue">Quasicristal</font> (''Fr''); <Font color="red">Quasikristall</font> (''Ge''); <Font color="green">Cuasicristal</font> (''Sp''); <Font color="black">Quasicristallo</font> (''It''); <Font color="brown">Квазикристалл</font> (''Ru''); <Font color="purple">準結晶</font> (''Ja'').
+<Font color="blue">Quasicristal</font> (''Fr''). <Font color="red">Quasikristall</font> (''Ge''). <Font color="green">Cuasicristal</font> (''Sp''). <Font color="black">Quasicristallo</font> (''It''). <Font color="brown">Квазикристалл</font> (''Ru''). <Font color="purple">準結晶</font> (''Ja'').
 There are two definitions of the notion of quasicrystal.
-* 1)  A  ''quasicrystal'' is an aperiodic crystal that is not an incommensurate modulated structure, nor an aperiodic composite crystal. Often, quasicrystals have crystallographically 'forbidden' symmetries. These are rotations of order different from 1, 2, 3, 4 and 6. In three dimensions a lattice periodic structure may only have rotation symmetry of an order equal to one of these numbers. However, presence of such a forbidden symmetry is not required for a quasicrystal. A system with crystallographically allowed rotation symmetry that is locally similar to one with forbidden symmetries is also a quasicrystal.
+* 1. A  ''quasicrystal'' is an aperiodic crystal that is not an incommensurate modulated structure, nor an aperiodic composite crystal. Often, quasicrystals have crystallographically 'forbidden' symmetries. These are rotations of order different from 1, 2, 3, 4 and 6. In three dimensions a lattice periodic structure may only have rotation symmetry of an order equal to one of these numbers. However, presence of such a forbidden symmetry is not required for a quasicrystal. A system with crystallographically allowed rotation symmetry that is locally similar to one with forbidden symmetries is also a quasicrystal.
-* 2) The term  ''quasicrystal'' stems from the property of quasiperiodicity observed for the first alloys found with forbidden symmetries. Therefore, the alternative definition is: a  ''quasicrystal'' is an aperiodic crystal with diffraction peaks that may be indexed by ''n'' integral indices, where ''n'' is a finite number, larger than the dimension of the space (in general). This definition is similar to that of  [[aperiodic crystal]].
+* 2. The term  ''quasicrystal'' stems from the property of quasiperiodicity observed for the first alloys found with forbidden symmetries. Therefore, the alternative definition is: a  ''quasicrystal'' is an aperiodic crystal with diffraction peaks that may be indexed by ''n'' integral indices, where ''n'' is a finite number, larger than the dimension of the space (in general). This definition is similar to that of  [[aperiodic crystal]].
 == See also ==
-[[Aperiodic crystal]]
+*[[Aperiodic crystal]]
 [[Category: Fundamental crystallography]]

← Older revision		Revision as of 11:41, 14 April 2016
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−	<Font color="blue">Quasicristal</font> (Fr.), <Font color="black">Quasicristallo</font> (It.), <Font color="purple">準結晶</font> (Ja.),	+	<Font color="blue">Quasicristal</font> (''Fr''); <Font color="red">Quasikristall</font> (''Ge''); <Font color="green">Cuasicristal</font> (''Sp''); <Font color="black">Quasicristallo</font> (''It''); <Font color="brown">Квазикристалл</font> (''Ru''); <Font color="purple">準結晶</font> (''Ja'').

← Older revision		Revision as of 07:53, 26 February 2015
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	== See also ==		== See also ==
	[[Aperiodic crystal]]		[[Aperiodic crystal]]
		+
		+
		+	[[Category: Fundamental crystallography]]

← Older revision		Revision as of 08:35, 8 February 2012
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−	<Font color="blue">Quasicristal</font> (Fr.)	+	<Font color="blue">Quasicristal</font> (Fr.), <Font color="black">Quasicristallo</font> (It.), <Font color="purple">準結晶</font> (Ja.),

← Older revision		Revision as of 15:51, 18 May 2009
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	[[Quasicrystal]]		[[Quasicrystal]]

−	Quasicristal (Fr.)	+
		+	<Font color="blue">Quasicristal</font> (Fr.)