- fourfold rotation axis
- nCRYSTALL eje de rotación cuaternario m, eje de simetría cuaternario m
English-Spanish technical dictionary. - London, © Routledge. 1997.
English-Spanish technical dictionary. - London, © Routledge. 1997.
Swastika origin theories — The earliest archaeological evidence of a swastika motif dates from the Upper Paleolithic period (ca. 10,000 BC). It appears on birds carved from mammoth tusk and the motif is etched at the spot where the bird s feet should be. This carving is… … Wikipedia
Symmetry — For other uses, see Symmetry (disambiguation) … Wikipedia
Crystal system — Diamond crystal structure consists of face centered cubic lattice. In crystallography, the terms crystal system, crystal family, and lattice system each refer to one of several classes of space groups, lattices, point groups, or crystals.… … Wikipedia
Octomino — The 369 free octominoes An octomino (or 8 omino) is a polyomino of order 8, that is, a polygon in the plane made of 8 equal sized squares connected edge to edge.[1] The name of this type of figure is formed with the prefix … Wikipedia
Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… … Universalium
Nonomino — A nonomino (enneomino or 9 omino) is a polyomino of order 9, that is, a polygon in the plane made of 9 equal sized squares connected edge to edge.[1] The name of this type of figure is formed with the prefix non(a) . When rotations and… … Wikipedia
Magnetocrystalline anisotropy — is the dependence of the internal energy of a ferromagnet on the direction of its magnetization. As a result, certain crystallographic directions are preferred directions, or easy axes, for the magnetization. It is a special case of magnetic… … Wikipedia
quasicrystal — /kway zuy kris tl, kway suy , kwah see , zee /, n. a form of solid matter whose atoms are arranged like those of a crystal but assume patterns that do not exactly repeat themselves. [1985 90] * * * Introduction also called quasi periodic crystal … Universalium
Oblique effect — is the name given to the relative deficiency in perceptual performance for oblique contours as compared to the performance for horizontal or vertical contours. Contents 1 Background 2 The Phenomenon 3 Origin of the Oblique Effect … Wikipedia
Nebular hypothesis — Star formation Interstellar medium Molecular cloud … Wikipedia
Cement mill — A 10 MW cement mill, output 270 tonnes per hour A cement mill (or finish mill in North American usage[1]) is the equipment used to grind the hard, nodular clinker from the cement kiln into the fine grey powder that is cement. Most cement is… … Wikipedia