TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 OBS

Usually three, sometimes four, lines meeting at a point which are so chosen as to bear a definite relationship to the characteristic features of the crystallographic symmetry.  1, record 1, English, - crystallographic%20axes

Record 1,  Textual support,  French

Record 1,  Textual support,  Spanish

Record 2,  Textual support,  English

Record number: 2, Textual support number: 1 CONT

[Optical isomers] take their name from their effect of rotating the plane of polarization of a beam of polarized light that is directed through them : one member of each pair causes rotation in one direction, the other in the opposite direction. This phenomenon, called optical activity, arises from any of several kinds of imbalance in the three-dimensional structure of the molecule that cause it to have no point, line, or plane of symmetry.  2, record 2, English, - optical%20activity

Record 2,  Textual support,  French

Record number: 2, Textual support number: 1 DEF

Propriété qu'a une entité chimique ou physique chirale de faire tourner le plan de polarisation d'un faisceau de lumière polarisée plane.  2, record 2, French, - activit%C3%A9%20optique

Record number: 2, Textual support number: 1 CONT

On connaît un grand nombre de substances naturelles qui ne sont pas superposables à leur image dans un miroir et sont douées d'un pouvoir rotatoire dont le signe a justement une telle signification. Ces substances sont capables de faire tourner le plan de polarisation d'une lumière polarisée rectilignement soit vers la droite [...] soit vers la gauche [...] Elles sont douées d'activité optique [...]  3, record 2, French, - activit%C3%A9%20optique

Record number: 2, Textual support number: 1 OBS

Cette propriété se manifeste aussi par la dispersion rotatoire, le dichroïsme circulaire et la polarisation circulaire d'émission.  2, record 2, French, - activit%C3%A9%20optique

Record number: 2, Textual support number: 2 OBS

activité optique : terme et définition publiés au Journal officiel de la République française le 18 avril 2001.  4, record 2, French, - activit%C3%A9%20optique

Record 2,  Textual support,  Spanish

Record number: 2, Textual support number: 1 DEF

Poder rotatorio de algunas sustancias sobre la luz polarizada.  1, record 2, Spanish, - actividad%20%C3%B3ptica

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 DEF

A common form of polymer crystallization from melts or concentrated solutions.  1, record 3, English, - spherulite

Record number: 3, Textual support number: 1 OBS

These crystallites show a radial symmetry from a central point and have a distinctive maltese cross pattern of birefringence under the polarizing microscope.  1, record 3, English, - spherulite

Record 3,  Textual support,  French

Record number: 3, Textual support number: 1 DEF

Zone d'organisation des domaines cristallins à l'intérieur d'un polymère.  3, record 3, French, - sph%C3%A9rulite

Record number: 3, Textual support number: 1 CONT

L'examen au microscope polarisant, entre nicols croisés, a révélé qu'il s'agit de domaines sensiblement sphériques [...] et coupés par une croix de Malte dont les bras sont parallèles au polariseur et à l'analyseur. Cela est caractéristique d'assemblages radiaux de petits cristaux. Chaque sphérulite est formé d'un faisceau de fibrilles partant d'un point central. La taille des phérulites dépend surtout des conditions de cristallisation.  3, record 3, French, - sph%C3%A9rulite

Record number: 3, Textual support number: 2 CONT

Lorsqu'un polymère fondu est refroidi très lentement, il a tendance à se cristalliser en une structure pliée en accordéon, ou pelotonnée, formant ainsi un sphérulite.  4, record 3, French, - sph%C3%A9rulite

Record 3,  Textual support,  Spanish

Record 4,  Textual support,  English

Record number: 4, Textual support number: 1 DEF

In meteorology, a point in a time series for which the rate of change of an element on either side and at an equal distance of the point has the same magnitude but the opposite sign.  2, record 4, English, - symmetry%20point

Record 4,  Textual support,  French

Record number: 4, Textual support number: 1 DEF

En météorologie, point d'une série chronologique pour lequel le taux de variation d'un élément de part et d'autre et à égale distance de ce point a la même valeur mais est de signe contraire.  2, record 4, French, - point%20de%20sym%C3%A9trie

Record 4,  Textual support,  Spanish

Record number: 4, Textual support number: 1 DEF

En meteorología, punto de una serie cronológica en el que la tasa de variación de un elemento a uno y otro lado de ese punto tiene igual magnitud pero es de signo opuesto.  1, record 4, Spanish, - punto%20de%20simetr%C3%ADa

Record 5,  Textual support,  English

Record number: 5, Textual support number: 1 DEF

Having the symmetry of a "pyramid".... An open crystal form consisting of three, four, six, eight, or twelve nonparallel faces that meet at a point.  2, record 5, English, - pyramidal

Record 5,  Textual support,  French

Record number: 5, Textual support number: 1 OBS

[...] les faces principales ou prédominantes se rencontrent en pointes opposées; les cristaux ont un aspect de pyramide, simple ou double.  2, record 5, French, - pyramidal

Record 5,  Textual support,  Spanish

Record 6,  Textual support,  English

Record number: 6, Textual support number: 1 DEF

Material having mechanical properties that are not the same in all directions at a point in a body of it. There are no planes of material symmetry. That is the properties are a function of the orientation at a point.  1, record 6, English, - anisotropic%20material

Record 6,  Textual support,  French

Record number: 6, Textual support number: 1 CONT

La matière anisotrope a une direction de diffusion privilégiée. Une fois polarisée la lumière fait la différence entre ces deux types de milieux ce qui permet de les identifier. En effet les indices d'anisotropie des matériaux sont répertoriés [...]  1, record 6, French, - mati%C3%A8re%20anisotrope

Record 6,  Textual support,  Spanish

Record 7,  Textual support,  English

Record number: 7, Textual support number: 1 CONT

Mirror symmetry, that is, invariance against "flipping sides", is perhaps the most widely noticed symmetry. Nature built many of her organisms in nearly symmetric ways, and most fundamental laws of physics, such as Newton's law of gravitation, have an exact mirror symmetry : there is no difference between left and right in the attraction of heavenly(and most earthbound) bodies. However, the nonconservation of parity in radioactive decay-that is, the violation of point symmetry in the "weak" interactions-has finally taught even the physicists to take the distinction between right and left seriously.  2, record 7, English, - mirror%20symmetry

Record 7,  Textual support,  French

Record number: 7, Textual support number: 1 DEF

[...] symétrie signifiant que le corps est divisé en deux parties, chacune image de l'autre dans un miroir. C'est la notion courante de symétrie bilatérale.  2, record 7, French, - sym%C3%A9trie%20bilat%C3%A9rale

Record 7,  Textual support,  Spanish

Record 8,  Textual support,  English

Record number: 8, Textual support number: 1 CONT

Spontaneous symmetry breaking. The ball is placed on top of the "Mexican hat" surface. In this configuration there is complete rotational symmetry. However, the configuration is unstable, and the ball spontaneously rolls down into the rim of the "hat", coming to rest at some arbitrary point. The rotational symmetry is thereby broken. The system has traded symmetry for stability.  2, record 8, English, - symmetry%20breaking

Record 8,  Textual support,  French

Record number: 8, Textual support number: 1 DEF

Changement de la symétrie d'une structure, ou perte de symétrie de deux structures, lorsque les conditions qui la favorisaient changent.  3, record 8, French, - brisure%20de%20sym%C3%A9trie

Record number: 8, Textual support number: 1 OBS

Par exemple, les désordres d'empilement, les degrés d'ordre, les lacunes et les substitutions dans un réseau, les surstructures, les solides à dimensionnalité réduite, les matériaux incommensurables, les quasi-cristaux, le «dopage» des semi-conducteurs.  3, record 8, French, - brisure%20de%20sym%C3%A9trie

Record number: 8, Textual support number: 1 PHR

La brisure de symétrie engendre des structures, se manifeste, se produit, résulte d'une différence de symétrie.  3, record 8, French, - brisure%20de%20sym%C3%A9trie

Record number: 8, Textual support number: 2 PHR

engendrer, provoquer une brisure de symétrie.  3, record 8, French, - brisure%20de%20sym%C3%A9trie

Record 8,  Textual support,  Spanish

Record 9,  Textual support,  English

Record number: 9, Textual support number: 1 CONT

"Symmetry classes". Every crystal belongs to one of the 32 different classes of symmetry, or point groups. The standard notation for describing these classes is that of Schoenflies, who assigned symbols to the various possible symmetry elements according to the following rules : Symbol : C_n. Symmetry Element Possessed by Group : n-fold axis.... Symbol : T(tetrahedral). Symmetry Element Possessed by Group : four three-fold axes towards vertices or regular tetrahedron. Symbol : O. Symmetry Element Possessed By Group : three mutually perpendicular four-fold axes(cubic group).  1, record 9, English, - n%2Dfold%20axis

Record number: 9, Textual support number: 1 OBS

symmetry": In general, a figure or expression is said to be symmetric if parts of it may be interchanged without changing the whole. ... A right circular cone has an axis of symmetry. A geometric figure has n-fold rotational symmetry about an axis if a rotation of 360°/n is a symmetry of the figure. Thus an axis of symmetry can be a rotational axis. For example, an axis through the centre of a square perpendicular to the plane is a 4-fold axis since a rotation of 360°/4 produces an identical figure; a diagonal is a 2-fold axis.  2, record 9, English, - n%2Dfold%20axis

Record 9,  Textual support,  French

Record number: 9, Textual support number: 1 CONT

Un axe de symétrie est dit axe d'ordre n par rapport à une surface ou à un système de plan, et, en minéralogie, par rapport à une face, quand cet axe de symétrie est tel qu'en faisant tourner la figure de 2 [pi]/n, on retombe sur la surface primitive.  1, record 9, French, - axe%20de%20sym%C3%A9trie%20d%27ordre%20n

Record 9,  Textual support,  Spanish

Record 10,  Textual support,  English

Record number: 10, Textual support number: 1 OBS

A geometric configuration(curve, surface, etc.) is said to be symmetric(have symmetry) with respect to a point, a line, or a plane, when for every point on the configuration there is another point of the configuration such that the pair is symmetric with respect to the point, line, or plane.  2, record 10, English, - plane%20symmetry

Record 10,  Textual support,  French

Record number: 10, Textual support number: 1 CONT

Symétrie par rapport à un plan P: Symétrie dont l'ensemble des points invariants est le plan P.  1, record 10, French, - sym%C3%A9trie%20par%20rapport%20%C3%A0%20un%20plan

Record 10,  Textual support,  Spanish

Record 11,  Textual support,  French

Record 11,  Textual support,  Spanish

Record 12,  Textual support,  English

Record number: 12, Textual support number: 1 OBS

A point in a crystal structure through which every aspect of an array is repeated by inversion. It is a symmetry element.  1, record 12, English, - centre%20of%20symmetry

Record 12,  Textual support,  French

Record number: 12, Textual support number: 1 OBS

Un centre de symétrie est tel qu'à tout point M d'une figure correspond un point M' situé sur la droite joignant M à ce centre et à la même distance.  1, record 12, French, - centre%20de%20sym%C3%A9trie

Record 12,  Textual support,  Spanish

Record 13,  Textual support,  English

Record number: 13, Textual support number: 1 OBS

The position of the chord line is defined by the coordinates(x, y, z) of its quarter-chord point and its inclination(o) to the x-y plane. The direction and sign conventions of the co-ordinate axes are given in the Appendix. The origin of the co-ordinates is a fixed point in the plane of symmetry  1, record 13, English, - chord%20position

Record 13,  Textual support,  French

Record 13,  Textual support,  Spanish