Order and disorder

Systems in which the disorder length scale is large compared to the electronic correlation length are described as heterogeneously disordered.  

The resistance in such a heterogeneous system can be written as the sum of the more ordered parts and the barrier parts, and the overall mathematical description correlates well to the experimental data. The crossover temperature observed in the intrinsically conductive polymers can be well described based on the contributions from highly conductive, ordered regions as well as poorly conductive disordered regions. This model also explains the linear increase of the thermoelectric power with temperature since the heat is carried by lattice vibration and charge carriers, but the carrier diffusion itself is dominated by the ordered regions.  

Schematic illustration of spatial relationship of two metallic dots made of conducting polymers separated by insulating (disordered) regions. (Reprinted from Physica B Condensed Matter, 338(114) V. N. Prigodin and A. J. Epstein, Quantum hopping in metallic polymers. Copyright 2003, with permission from Elsevier.) 

For a random network of coupled one-dimensional metallic wires, Prigodin and Efetov predicted four different conductivity modes dependent on the temperature. Initially the material shows a conductivity of variable range hopping. The next transport mode is the hopping over nearest states followed by regions of localization correlations. Finally band transport is reached. 

For a one-dimensional system the variable range hopping is described by Mott s temperature law  

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B. Roessler, D.T. Novick and M B. Bever, Aimealing of the ordered and disordered alloy Cu,Au after cold work, Trans. Met. Soc. AIME 227 985 (1963). 

B. Urban-Erbil and W. Pfeiler, Ordering and disordering in CuPt-alloys, in. .Ordering and Disordering in... 

R. Ebner, M. Migschitz, C. Scholz, B. Urban-Erbil, P. Fratzl and W. Pfeiler, LI, -ordering and disordering... 

RELATIVISTIC CALCULATIONS OF PHOTOEMISSION-AND LEED-INTENSITIES FOR ORDERED AND DISORDERED ALLOYS APPLICATION TO CusPt and Cu Pta... 

Gonis, A., 1992, Green Functions for Ordered and Disordered Systems, North Holland Elsevier Science Publishers B.V., Amsterdam. 

Let us fix attention on a particular H20 molecule A in the interior of water (if we wish to identify this molecule we can suppose that it contains a nucleus of the oxygen isotope 01S) and let us consider the water molecules which happen to be nearest neighbors of this molecule at the moment. These molecules have been in contact with A for different lengths of time. Since all the molecules in the liquid wander about, there was a time when none of these molecules was in contact with A. Further, if we could now begin to watch these molecules, we should find that, after the lapse of different periods of time, they become separated from A and each is replaced by another molecule. Similar remarks can be made about the molecules which come into contact with any chosen molecule. We can now raise the question—-What is the rate of turnover of this process The rate depends on the degree of local order and disorder, which in turn depends on the strength and character of the forces between adjacent molecules. 

Correlation between Ionic Entropy and Viscosity. In Chapter 9, when we noticed that certain ions in aqueous solution cause a decrease in viscosity, and asked how this should be explained, it seemed natural to interpret the effect in terms of order and disorder. In pure water at room temperature there is a considerable degree of short-range order ... 

The Orientation of Water Molecules Adjacent to an Ion. Order and Disorder in the Vicinity of Solute Particles. Coulomb Attraction and Repulsion between Ions. Activity Coefficients. The Distance of Closest Approach. Activity Coefficients of Various Solutes. Forces Superimposed on the Coulomb Forces. 

The measured growth rates are illustrated by the circles in Fig. 7. The interface velocity is plotted versus the interface temperature T. The value of T is always greater than Tq because of the release of the latent heat at the interface. Dimensionless units for T and the velocity are used here. The maximum velocity corresponds to 80m /s for argon. The most surprising aspect is the rapid crystallization at low temperatures. Most materials exhibit sharply reduced rates at low temperatures, as expected for an activated growth process. That is, the kinetics can be represented as the product of an Arrhenius factor F(T) and a term that accounts for the net production of crystalline material as a result of the atoms ordering and disordering at the interface,... 

In the framework of the mobile order and disorder (MOD) theory five components contribute most to the Gibbs free energy of partitioning of a solute in a biphasic system of two essentially immiscible solvents [23] ... 

Ruelle, P. Universal model based on the mobile order and disorder theory for predicting lipophilidty and partition coefficients in all mutually immiscible two-phase liquid systems. Chem. Inf. Comput. Sci. 2000, 40, 681-700. 

Watanabe M, Tsurumi K, Mizukami T, Nakamura T, Stonehart P. 1994. Activity and stability of ordered and disordered Co-Pt alloys for phosphoric acid fuel cells. J Electrochem Soc 141 2659-2668. 

Auo.8Cro.2 Hyperfine field and isomer shift in crystallographically ordered and disordered phases... 

Blinc R (2007) Order and Disorder in Perovskites and Relaxor Ferroelectrics. 124 51-67 Boca R (2005) Magnetic Parameters and Magnetic Functions in Mononuclear Complexes Beyond the Spin-Hamiltonian Formalism 117 1-268 Bohrer D, see Schetinger MRC (2003) 104 99-138 Bonnet S, see Baranoff E (2007) 123 41-78... 

Kitaigorodsky, A. I. Order and Disorder in the World of Atoms, The Heidelberg Science Library, Vol. 3, New York, Springer Verlag 1967... 

Michalowicz, A., Verdaguer, M., Mathey, Y., and Clement, R. Order and Disorder in Low Dimensional Materials Beyond the First Coordination Sphere with E.X.A.F.S., 145, 107-149 (1987). Montanari, F., Landini, D., and Rolla, F. Phase-Transfer Catalyzed Reactions. 101, 149-200 (1982). 

Xanthan is reported to undergo a chiroptically detected temperature or salt-driven conformational change from an ordered conformation at high salt and low temperature to a disordered conformation either associated with lowering the salt concentration, or with increasing the temperature (2-5). The primary structure of xanthan has been known for about a decade (6,7), but different structures have been suggested both for the ordered and disordered conformation. Some workers (8-13) conclude that the ordered conformation is double-stranded or double-helix, whereas others (14-17) claim that a single stranded description can account for the observed data under... 

In this study we use electron microscopy (EM) to study xanthan strandedness and topology both in the ordered and disordered conformation. Correlation of data obtained from electron micrographs to physical properties of dilute aqueous solution on the same sample will be used to provide a working hypothesis of the solution configuration of xanthan. Electron micrographs obtained from xanthan of different origins will be compared to assess similarities and differences in secondary structure at the level of resolution in the used EM technique. 

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