Ordering patterns helical

If the canting is not the same for each magnetic cation but varies in a regular way, then a number of commensurate or incommensurate spin structures can arise, including helical, helicoidal, cycloidal and sinusoidal. The helicoidal and sinusoidal ordering patterns are illustrated by the magnetic structure of TbMnOj (Section 7.10). 

First, in the striated muscles, the cross-sectional organization of filaments is highly ordered in a hexagonal pattern commensurate with the ratio of actin to myosin filaments and the distribution of active myosin heads, S-1 segments, helically every 60 degrees around the myosin filament. In smooth muscle, with perhaps 13 actin filaments per myosin filament, many actin filaments appear to be ranked in layers around myosin filaments. It is not known how the more distant actin filaments participate in contraction. 

As already shown in Figure 2.29a, in the ideal limit-ordered model of form I of sPP, right- and left-handed twofold helical chains alternate along the a and b axes of the orthorhombic unit cell.59 In the electron diffraction patterns of single crystals grown at low temperatures, reported by Lovinger et al.,145 the... 

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