Parallel to the body

In this work we use an adiabatic electronic representation, and Jacobi nuclear coordinates are chosen r, the HE internuclear vector, and R, the vector joining the HE center-of-mass to the Li atom, in a body-fixed frame in which the three atoms lie on the a — body-fixed plane, with R being parallel to the body-fixed... 

Attention should perhaps be drawn to the characteristic symmetry of the cubic system which is not, as might be supposed, the 4-fold (or 2-fold) axes of symmetry or planes of symmetry but four 3-fold axes parallel to the body-diagonals of the cubic unit cell. This combination of inclined 3-fold axes introduces either three 2-fold or three 4-fold axes which are mutually perpendicular and parallel to the cubic axes. Further axes and planes of symmetry may be present but are not essential to cubic symmetry and do not occur in all the cubic point groups or space groups. 

The sequence ABC ABC... possesses cubic symmetry, that is, 3-fold axes of symmetry in four directions parallel to the body-diagonals of a cube, and is therefore described as cubic closest packing (c.c.p.). A unit cell is shown in Fig. 4.1(e) (p. 120) and the packing is also illustrated in Fig. 4.14. The close-packed layers seen in plan in Fig. 4.12 are perpendicular to any body-diagonal of the cube. Since the atoms in c.c.p. are situated at the corners and mid-points of the faces of the cubic unit cell the alternative name face-centred cubic (f.c.c.) is also applied to this packing. All atoms have their twelve nearest neighbours at the vertices of a cuboctahedron. (Fig. 4.5(b)). 

We saw in Chapter 2 that the characteristic (minimum) symmetry of a cubic crystal is the set of 3-fold axes parallel to the body-diagonals of the cubic cell. These 3-fold axes also imply 2-fold axes parallel to the cube edges. The NaCl structure has the highest class of cubic symmetry, with 4-fold axes and planes of symmetry. An octahedral ion such as (TlCl ) also has full cubic symmetry (m3m) can occupy the Cl positions in the normal NaCl structure. Groups such as S2, (F—H-F) , and CN have lower symmetry and can form the fully symmetrical NaCl structure only if they are rotating or are randomly oriented with their centres... 

F—H—F) zbns in 4 orientations parallel to the body-diagonals of the cube... 

It follows that the presence of a body force leads to a nonzero gradient of pressure parallel to the body force even in a stationary fluid. Indeed, it is well know that the pressure increases with depth under the action of gravity. Provided the fluid density remains constant, the pressure increases linearly with depth... 

Axes of symmetry. An axis about which rotation of the body through an angle of 2njn (where n is an integer) gives an identical pattern 2-fold, 3-fold, 4-fold and 6-fold axes are known in crystals 5-fold axes are known in molecules. In a lattice the rotation may be accompanied by a lateral movement parallel to the axis (screw axis). 

The drag force is exerted in a direction parallel to the fluid velocity. Equation (6-227) defines the drag coefficient. For some sohd bodies, such as aerofoils, a hft force component perpendicular to the liquid velocity is also exerted. For free-falling particles, hft forces are generally not important. However, even spherical particles experience lift forces in shear flows near solid surfaces. 

As shown in the free-body diagram of Figure 2-15b, all the motion of the block is parallel to the surface of the ramp thus there is a static force balance in the y direction. 

Hie chromatinic structures in E. coli from old cultures were too small to be resolved accurately. After transfer to fresh medium the chromatinic structures increased in size and gave rise to short, often dumbbell-shaped rods or chromosomes, which multiplied by splitting lengthwise in a plane more or less parallel to the short axis of the cell. A single cell of E. coli contained one chromatinic body or one or two pairs of these representing primary and secondary division products. 

A selvedge made by looping the weft thread round a wire (later withdrawn) parallel to the warp, thus leaving a series of small loops along the cloth edge, so that the thickness of the selvedge is the same as that of the body of the cloth. 

Figure 5.8 Interstitial diffusion (a) interstitial diffusion involving the direct migration of an interstitial atom to an adjacent site in the crystal (b, c) some of the octahedral and tetrahedral interstitial sites in the body-centered cubic structure of metals such as iron and tungsten and (d) the total number of octahedral and tetrahedral sites in a unit cell of the body-centered cubic structure. Diffusion paths parallel to the unit cell edges can occur by a series of alternating octahedral and tetrahedral site jumps, dashed line.

Most of the odours coming from livestock production units are associated with the biological degradation of the animal wastes (35), the feed and the body odour of the animals (1). Volatile fatty acids and phenolic compounds were found to contribute mostly to the strong, typical odour of animal houses by the help of sensory evaluations parallel to the chemical analysis (29), (30). 

FIG. 11.8 (a) A section of the difference synthesis through the Cr nucleus, parallel to the (110) plane. Contours are drawn at intervals of 0.2 eA 3. (b) Theoretical contour map of valence electron distribution on the (110) plane for chromium metal. Contours are drawn at intervals of 0.5 eA-3. The lobes point towards the nearest neighbors in the body-centered cubic structure. Source Ohba et al. (1982). 

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