Microscopic inhomogeneities

As it is known [5], the intensity of the scattered light gives us an information about the system s disorder, e.g., presence therein of pores, impurities etc. Since macroscopically liquid is homogeneous, critical opalescence arises due to local microscopic inhomogeneities - an appearance of small domains with different local densities. In other words, liquid is ordered inside these domains but still disorded on the whole since domains are randomly distributed in size and space, they appear and disappear by chance. Fluctuations of the order parameter have large amplitude and involve a wide spectrum of the wavelengths (which results in the milk colour of the scattered light). 

A number of important questions, however, still remain open. The first is which ion displacements Pb or Nb/Mg/Sc are responsible for the formation of polar regions What is the nature of non-polar matrix into which polar clusters are assumed to be embedded Are the polar clusters and the non-polar matrix dynamic or static entities Another still open important problem in PMN relaxor is related to microscopic inhomogeneities in the site occupancy of the Mg2-1" and Nb5+ cations and their role in the formation of the polar regions. An existence of a 1 1 Mg/Nb ordered microregions is still discussed in literature. Since the 1 1 Sc/ Nb chemical order in PbSci/2Nbi/203 really exists, a comparative study of the high-temperature local structure of these two relaxors is of interest. 

In Sections 2.2 and 2.3, it is described that the network structures of polymer gels, especially microscopic inhomogeneity, may be detected through the diffusion behaviour of probe molecules of different sizes, which can be obtained by using time-dependent diffusion NMR spectroscopy. In this section, it will be... 

Experimental studies on the ionization associated with particles in flames show that while such ionization occmrs to a measurable extent, it is frequently associated with and even masked by ionization derived from gaseous material. The volatilization of such material can be a slow process and the dispersion of the vapor by diffusion even slower, so that each particle is marked by a meteor trail of ionized gas. Even when the particle has volatilized completely, such a trail may give the appearance of particulate matter. One result of this microscopic inhomogeneity is that estimates of the evaporation of droplets which assume a uniform distribution of vapor can be grossly in error. 

Ise, N. When does like like like microscopic inhomogeneity in homogeneous ionic systems. Proceedings of the Japan Academy Series B-Physical and Biological Sciences, 2002, 78, No. 6, p. 129-137. 

The reason that chemical laws are not simply reduced to electrostatics is that the electrons behave under the influence of their own or applied electric fields, not according to classical mechanics, but according to quantum mechanics obeying the singular Pauli principle. In fact, electrostatics and dielectric constants are simpler applications of the electrical structure of molecules and use outside macroscopic homogeneous electric fields interacting with microscopic inhomogeneous fields. 

Materials Analysis. The next level of complexity involves the measurement of dielectric properties for the determination of composition and microstructure as well as thicknesses. Thin films are typically microscopically inhomogeneous with substantial fractions of grain boundaries and voids, so their dielectric properties are rarely equal to those of the corresponding materials in bulk form. As an example, the pseudodielactric function <(> film deposited by low pressure... 

In conclusion one must note that the search for further qualitative improvement of thermoelectric material is not restricted to creation of FGM structures formed by the monotonous macroscopic material inhomogeneities. Of exceptional interest is creation of the microscopic inhomogeneities with quantum well formation, as well as the inhomogeneous structures allowing to combine on the microscopic level both thermoelectric and emission ways of thermoelectricity generation in a solid body. These possibilities were discussed in detail at the VII International School on Thermoelectricity and published in the Journal of Thermoelectricity [5,6]. 

The Lorentz-Lorenz case in which the material is so microscopically inhomogeneous that the spatial distribution of OL is disjoint. The local-field correction is then L P,... 

Diffuse reflectance at interfaces which are structured and are microscopically inhomogeneous such that a large number of micro-reflecting surfaces distribute the reflected light statistically into space. 

L.W. Barbour, M. Hegadorn, and J.B. Asbury, Microscopic inhomogeneity and ultrafast orientational motion in an organic photovoltaic bulk heterojunction thin film studied with 2D IR vibrational spectroscopy, J. Phys. Chem. B, 110, 24281-24286 (2006). 

In some experiments, the samples were annealed to, or held at, 120 °C. We found this reduced some microscopic inhomogeneities in the extruded films. 

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