Packing, hexagonal

Muller D J, Baumeister W and Engel A 1996 Conformational change of the hexagonally packed intermediate layer of Deinococcus radiodurans monitored by atomic force microscopy J. Bactehol. 178 3025... 

LB films of 1,4,8,11,15,18-hexaoctyl-22,25-bis-(carboxypropyl)-phthalocyanine (2), an asymmetrically substituted phthalocyanine, were stable monolayers formed at the water—air interface that could be transferred onto hydrophilic siUca substrates (32—34). When a monolayer film of the phthalocyanine derivative was heated, there was a remarkable change in the optical spectmm. This, by comparison to the spectmm of the bulk material, indicated a phase transition from the low temperature herringbone packing, to a high temperature hexagonal packing. 

The electronic properties of single-walled carbon nanotubes have been studied theoretically using different methods[4-12. It is found that if n — wr is a multiple of 3, the nanotube will be metallic otherwise, it wiU exhibit a semiconducting behavior. Calculations on a 2D array of identical armchair nanotubes with parallel tube axes within the local density approximation framework indicate that a crystal with a hexagonal packing of the tubes is most stable, and that intertubule interactions render the system semiconducting with a zero energy gap[35]. 

Figure 4 Schematic representation of microspheres showing a two-dimensional hexagonal packing arrangement [24].

The chain arrangement of this morphology was schematically proposed as in Fig. 10. The cell of the microsphere has a hexagonal surface, and the AB diblock copolymers form a bilayer between the microspheres. From this schematic arrangement, the optimal blend ratio of the AB block copolymer in this system was calculated as 0.46. This value was very close to the blend ratio of the AB type block copolymer 0.5 at which the blend showed the hexagonal packed honeycomb-like structure. 

The degree of ordering of the microspheres was estimated by using the radial distribution function g(D) of the P4VP cores of the microspheres (Fig. 11). As previously described, for hexagonal packed spheres, the ratio of the peaks of the distances between the centers of the cores would be For the film at r = 0.5, the... 

It has 6-coordinate osmium in a structure (Figure 1.2) regarded as being made from a hexagonally packed array of chlorides with osmiums occupying half the holes in alternate layers Os-Cl bond lengths are 2.261 A (terminal) and 2.378 A (bridge) [20]. 

Figure 3. Structure of a muscle sarcomere. In a polarizing microscope muscle appears to have dark (A) and light (I) bands. The l-band region only contains thin filaments. The A-band region contains both thick and thin filaments. One sarcomere is the distance between two Z-lines. In cross section, the hexagonal packing of the thick and thin filaments can be seen.

The morphology of the ABA-type linear block copolymers is strongly influenced by the volume fraction of the two components. For example, in PS-EB-PS-type block copolymer as the volume fraction of PS is increased, the shape of the dispersed PS phase changes from spherical (comprising body-centered cubic spheres of PS dispersed in continuous soft phase) to cylindrical form (hexagonal packed cylinders of PS) [10,133,134]. When the volume fraction of the two phases... 

Fig. 7.6 Crystal packing of neutral Mo3S7 dmit)3 cluster along the c direction (a) and view of the hexagonal packing across the ab plane (b).

Similar to the sitnation with DNA structures formed under osmotic stress, DNA strands in cation-condensed bundles were found to be hexagonally packed and to possess liqnid crystalline order. For example, spermine and spermidine-condensed samples were fonnd to contain a cholesteric phase [70]. Surprisingly, DNA condensed with (Co(NH3)6) failed to exhibit a liquid crystalline ordering [47]. 

Here, we use a hexagonally-packed representation of atoms to depict the close-packed solid. In this case, we have shown both types of homogeneous solids. That is, one solid is composed of the same sized atoms while the other is composed of two different sized atoms. 

The heat transfer data discussed above refer only to the average behavior of a vial of a given type which is surrounded by other vials in a hexagonal packing array of vials. We now consider intervial variations in heat transfer in a set of nominally equivalent vials and variations in heat transfer arising from variations in the position of the vial in the array. An experiment demonstrating such variations is described by Figure 35. Each circle represents a vial placed on a temperature-controlled shelf in a small laboratory freeze dryer. The vials contained pure... 

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