Inclusions incoherent

Incoherent Clusters. As described in Section B.l, for incoherent interfaces all of the lattice registry characteristic of the reference structure (usually taken as the crystal structure of the matrix in the case of phase transformations) is absent and the interface s core structure consists of all bad material. It is generally assumed that any shear stresses applied across such an interface can then be quickly relaxed by interface sliding (see Section 16.2) and that such an interface can therefore sustain only normal stresses. Material inside an enclosed, truly incoherent inclusion therefore behaves like a fluid under hydrostatic pressure. Nabarro used isotropic elasticity to find the elastic strain energy of an incoherent inclusion as a function of its shape [8]. The transformation strain was taken to be purely, dilational, the particle was assumed incompressible, and the shape was generalized to that of an... 

Figure 19.7 Elastic strain energy function E c/a) for an incoherent ellipsoid inclusion of aspect ratio c/a.

Section IV is devoted to excitons in a disordered lattice. In the first subsection, restricted to the 2D radiant exciton, we study how the coherent emission is hampered by such disorder as thermal fluctuation, static disorder, or surface annihilation by surface-molecule photodimerization. A sharp transition is shown to take place between coherent emission at low temperature (or weak extended disorder) and incoherent emission of small excitonic coherence domains at high temperature (strong extended disorder). Whereas a mean-field theory correctly deals with the long-range forces involved in emission, these approximations are reviewed and tested on a simple model case the nondipolar triplet naphthalene exciton. The very strong disorder then makes the inclusion of aggregates in the theory compulsory. From all this study, our conclusion is that an effective-medium theory needs an effective interaction as well as an effective potential, as shown by the comparison of our theoretical results with exact numerical calculations, with very satisfactory agreement at all concentrations. Lastly, the 3D case of a dipolar exciton with disorder is discussed qualitatively. 

Several techniques have been used to investigate dynamic properties of urea inclusion compounds, including solid-state NMR, incoherent quasielastic neutron scattering ESR, molecular dynamics simulation, Raman, infrared, dielectric loss, and x-ray diffraction. In addition to investigations of the dynamics of the guest molecules, the dynamic properties of the urea molecules have also been studied. 

Souaille. M. Guillaume, F. Smith. J.C. Molecular dynamics simulation of n-nonadecane in urea inclusion 67. compound. FT. Rotational distribution and elastic incoherent structure factor. J. Chem. Phys. 1996. 105. pp. 1516. 

The EMT can be considered as a basic tool for the analysis of IR spectta of inhomogeneous thin films, and it has been proven valid in many cases, provided that the working formula has been chosen properly (Section 3.9). However, the EMT is not sensitive to the positions or sizes of individual inclusions in the film. Moreover, in contrast to the Rayleigh law, it is inadequate in predicting the color and brightness of the sky, because it neglects incoherent scattering. 

Contemporaneously with Vohra, Michler and co-workers [32] carried out a detailed study of microwave-assisted CVD diamond film growth in methane/carbon dioxide gas mixtures on silicon wafers at different substrate temperatures (560-275°C) by XRD, transmission electron microscopy (TEM), AFM, and Raman spectroscopy. At temperatures above 430°C, the films consisted of nearly defect-free near-(112)-oriented grains with smooth (111) facets, exhibiting steps and risers at the surface. Below a transition region of 340-385°C, the film quality was much deteriorated, as evidenced by much smaller crystal size, increased twin density, and amorphous inclusions at incoherent twin boundaries. The Raman spectra (514.5-nm excitation) in the high-temperature region contained no peaks, but above the transition temperature, peaks at around 1430 and 1540 cm were evident, which the authors attributed to amorphous inclusions (Fig. 9). These observations are consistent with those of Vohra et al. [31] just mentioned. 

---