Stereo projection

There are two common variations on this notation. Sometimes, at the chiral centre, only three bonds may be shown, two of which are of normal thickness, while the third is either dashed or a solid wedge the fourth bond is to a hydrogen atom, and is not shown for it is assumed to be orientated as necessary to complete the usual geometry of the chiral centre. In the other common variation, three bonds to the chiral centre are represented with lines of normal thickness, and only the fourth uses a solid wedge or dashed line to indicate the stereochemistry. Neither of these variations are as clear as the normal version. 

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The absolute eonfiguration, (25, 45, 55 as shown or 2R,4R,5R), eannot be dedueed by NMR. For larger structures the insertion of the shift values and the coupling constants in the stereo projection of the struetural formula, from whieh one ean eonstruet a Dreiding model, proves useful in providing an overview of the stereoehemieal relationships. 

Figure 4. Confocal laser scanning microimages of compression film from formulation II. The organization of the biopolymers were resolved by confocal fluorescence (excitation 484 nm, emission 520-580 nm), the PEO was defined by confocal reflection (633 nm). The micrograph was collected in stereo projection in extended focus images of 20-30 micrometer-thick slabs of the film. Field width,...

Fig. 9. Determination of piezoelectricity direction based on point group 32. Stereo graphs (a), (b) and (c) with equivalent points are projected from [001], [100], and [210], respectively. X upper points, o opposite points. Configurations of a crystal with point group 32 also are drown for supporting the stereo projections, (d) and (e) show the crystal structure along [100] and [120] showing asymmetry and symmetry, respectively. Dipole moment will be appeared in (d).

Equation (1.4) gives the full expression, in which intensity varies with both polar angle 0 and azimuthal angle yt. K fiber symmetry is assumed, the intensity will be the same with given 0 and s and the integration of yields a constant In. Usually, a flat 2D detector is used to record the scattering pattern, which is a stereo-projection of 3D scattering intensity distribution. In this case, Fraser correction is needed to correct the distortion due to the stereo-projection [94]. The Hermans orientation function varies between -0.5 and 1. When /= -0.5, the normal and the reference axes are perpendicular to each other when /= 1, the normal is in parallel to the reference axis when / = 0, the system has random orientation. 

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