Quasi ordered structure

Another example is dendritic crystal growth under diffusion-limited conditions accompanied by potential or current oscillations. Wang et al. reported that electrodeposition of Cu and Zn in ultra-thin electrolyte showed electrochemical oscillation, giving beautiful nanostmctured filaments of the deposits [27,28]. Saliba et al. found a potential oscillation in the electrodeposition of Au at a liquid/air interface, in which the Au electrodeposition proceeds specifically along the liquid/air interface, producing thin films with concentric-circle patterns at the interface [29, 30]. Although only two-dimensional ordered structures are formed in these examples because of the quasi-two-dimensional field for electrodeposition, very recently, we found that... 

Figure 10.11 A well-ordered 2D AuS phase develops during annealing to 450 K. (A) The structure exhibits a very complex LEED pattern, which can be explained by an incommensurate structure with a nearly quadratic unit cell. (B) STM reveals the formation of large vacancy islands by Oswald ripening which cover about 50% of the surface, thus indicating the incorporation of 0.5 ML of Au atoms into the 2D AuS phase. The 2D AuS phase exhibits a quasi-rectangular structure (inset) and uniformly covers both vacancy islands and terrace areas. (Reproduced from Ref. 37).

An elastic continuum model, which takes into account the energy of bending, the dislocation energy, and the surface energy, was used as a first approximation to describe the mechanical properties of multilayer cage structures (94). A first-order phase transition from an evenly curved (quasi-spherical) structure into a... 

An example of such order is shown by the hexagonal symmetry of SBS as revealed by LAXD, electron microscopy and mechanical measurements. In composite materials the choice of phase is at the disposal of the material designer and the phase lattice and phase geometry may be chosen to optimise desired properties of the material. The reinforcing phase is usually regarded elastically as an inclusion in a matrix of the material to be reinforced. In most cases the inclusions do not occupy exactly periodic positions in the host phase so that quasi-hexagonal or quasi-cubic structure is obtained rather than, as in the copolymers, a nearly perfect ordered structure. 

We have considered here the influence of dispersion asymmetry and Zee-man splitting on the Josephson current through a superconductor/quantum wire/superconductor junction. We showed that the violation of chiral symmetry in a quantum wire results in qualitatively new effects in a weak superconductivity. In particularly, the interplay of Zeeman and Rashba interactions induces a Josephson current through the hybrid ID structure even in the absence of any phase difference between the superconductors. At low temperatures (T critical Josephson current. For a transparent junction with small or moderate dispersion asymmetry (characterized by the dimensionless parameter Aa = (vif — v2f)/(vif + V2f)) it appears, as a function of the Zeeman splitting Az, abruptly at Az hvp/L. In a low transparency (D Josephson current at special (resonance) conditions is of the order of yfD. In zero magnetic field the anomalous supercurrent disappears (as it should) since the spin-orbit interaction itself respects T-symmetry. However, the influence of the spin-orbit interaction on the critical Josephson current through a quasi-ID structure is still anomalous. Contrary to what holds... 

Polymers at interfaces are an important part of a large number of polymeric technological applications. The orientation, specific interactions, and higher order structures of amphiphilic molecules at a quasi two- dimensional plane form the basis of a variety of interesting phenomena [3-6], Scheme 3.1 shows a schematic representation of this behavior. 

The steady-state flow properties of block copolymers are often hard to measure. In steady shear, the shear stress often does not reach a clear steady-state value (Lyngaae-Jorgensen 1985). In cone-and-plate rheometers, steady shearing of an ordered block copolymer can result in edge fracture and flow irregularities, as might be expected when one forces a quasi-solid structure to flow (Winey et al. 1993a). 

In order to gain more insight into the nature of the fitness functions (IV.6) and (IV.7) as relevant for quasi-species structure, we employed a variety of representational tools ... 

Motivated by the remarkable discovery of quasicrystalline ordering in solids in 1984 [1], wave propagation in deterministic non periodic media has been an area of intense research. Following the successful experimental realisation of a multitude of such structures through modem technologies, such as molecular beam epitaxy and laser ablation [2], their interest has increased ever since. The most widely known examples are quasi-periodic structures obtained by substitution rules, such as Fibonacci- or Thue-Morse-chains [3,4], Much less has been published on quasi-periodic chains constructed according to a Cantor-set algorithm, which are the subject of this note. 

For example, it is possible to find with the help of the STM images that the highly crystalline nature of the oxide film on the nickel surfaces is Ni(100) in the alkaline solutions [46]. At low potentials, a well-ordered rhombic structure is formed, which is resistant to reduction and is assigned to the irreversible Ni(OH)2 formation. At higher potentials, it is possible to see a quasi-hexagonal structure consistent with NiO(lll). In other words, a crystalline oxide is formed of the NiO(lll) order independently of the crystal orientation of nickel. Moreover, it is very useful and practical to obtain a reduced surface by the cathodic treatments, where the hydrogen evolution produces the chemical and electrochemical reductions of nickel. However, this has to be done with careful attention and in light alkaline solutions to avoid nickel dissolution. When this is performed, monoatomic steps mostly oriented in the (100) and (111) directions are observed [47]. 

Fig. 6. However, these two structures are incompatible with one another and cannot co-exist and the molecules still fill space uniformly without forming defects. The matter is resolved by the formation of a periodic ordering of screw dislocations which enables a quasi-helical structure to co-exist with a layered structure. This is achieved by having small blocks/sheets of molecules, which have a local smectic structure, being rotated with respect to one another by a set of screw dislocations, thereby forming a helical structure [15]. As the macroscopic helix is formed with the aid of screw dislocations, the dislocations themselves must be periodic. It is predicted that rows of screw dislocations in the lattice will form grain boundaries in the phase, see Fig. 7, and hence this structurally frustrated phase, which was theoretically predicted by Renn and Lubensky [15], was called the twist grain boundary (TGB).

---