Orientated domains, crystal

The substituted five-ring OPVs have been processed into poly crystal line thin films by vacuum deposition onto a substrate from the vapor phase. Optical absorption and photolumincscence of the films are significantly different from dilute solution spectra, which indicates that intermolecular interactions play an important role in the solid-state spectra. The molecular orientation and crystal domain size can be increased by thermal annealing of the films. This control of the microstruc-ture is essential for the use of such films in photonic devices. 

Fig. 31 Structural formation model for the initial stage of polymer crystallization [19], N G nucleation and growth of oriented domains, SD spinodal decomposition into oriented and unoriented domains, Tb, Ts, and Tx bimodal, spinodal, and crystallization temperatures, respectively I isotropic, N smectic, and C crystalline...

Large domains of oriented single crystals of poly(TCDU) and poly(DMDA) were produced on the alkali halide surface. Figures 1 and 2 show the typical elongated platelet morphology. Selected... 

In many ferroelectric materials, the net piezoelectric effect is a result of both intrinsic and extrinsic responses. Here, intrinsic refers to the response that would result from an appropriately oriented single crystal (or ensemble thereof, in a polycrystalline sample). The extrinsic response is typically the result of motion of non-180° domain walls. The principle of these... 

It should be noted that a poling process is often necessary with single-crystal ferroelectric bodies because they contain a multiplicity of randomly oriented domains. There is therefore a sequence of states of increasing orderliness polycrystalline ferroelectric ceramics, poled ferroelectric ceramics, single-crystal ferroelectrics and single-domain single crystals. 

As a ferroelectric perovskite in ceramic form cools through its Curie point it contracts isotropically since the orientations of its component crystals are random. However, the individual crystals will have a tendency to assume the anisotropic shapes required by the orientation of their crystal axes. This tendency will be counteracted by the isotropic contraction of the cavities they occupy. As a consequence a complex system of differently oriented domains that minimizes the elastic strain energy within the crystals will become established. 

Skrynnikov, N. R., Goto, N. K., Yang, D., Choy, W. Y, Tolman, J. R., Mueller, G. A., and Kay, L. E. (2000). Orienting domains in proteins using dipolar couplings measured by liquid-state NMR Differences in solution and crystal forms of maltodextrin binding protein loaded with beta-cyclodextrin. J. Mol. Biol. 295, 1265-1273. 

Contributions of different crystallographically oriented domains are clearly indicated in the system Ag(cubooctahedron)/Tl using an electrochemically grown silver single crystal with (111) and (1(X)) faces as substrate as shown in Fig. 3.6 [3.95]. 

O.r, the surface area illuminated is about 1 cm. The patterns observed are therefore more likely to be powder patterns representing diffraction from many randomly oriented domains than the isolated peaks characteristic of single crystals. 

Figure 9. a) High-resolution image of a crystal exhibiting orientated domains. The simulated images are compared to the enlargement of the experimental images, b) Idealized model of the junction. 

In single crystals (strictly speaking in single-domain crystals) the relative magnitude of the non-oscillating term depends on the angle 0 between initial muon spin orientation and the direction of magnetization. Eq. (40) must be replaced by... 

The zirconia/mullite interphase has been examined indicating a coherent relation between both types of crystals, as is shown in Fig. 8. Only the A labeled grain shows this coherency while the B grain oriented with respect to the other does not show this effect. Therefore, the HREM allows us to distinguish the critical orientations of crystals at interphases. Domains of closure interpenetrating into the zirconia are visible at the boundary [25]. 

Finally the relation between the anisotropic structure and the shish structure is discussed. In the transmitted electron microscope (TEM) measurements, shish structures with diameter of about several nm have been reported in some polymers [16], It is clear that such a shish structure is different from the anisotropic oriented structure observed here because the spatial scale is very much different. Judging from the size of the anisotropic oriented structure, it must be a bundle of shish-kebab structures at least at the final stage of crystallization. Why is the 4,m scale structure formed in the initial stage of crystallization under shear flow One speculative answer is that tm scale phase separation occurs in the initial stage of crystallization between the oriented and unoriented regions, and then crystallization of stretched polymer chains occurs in the oriented domain after aggregation of the stretched chains. 

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