Amorphous cluster

The experimental observations of red shifts of the UV absorptions tails with increase in silicon dimensionality were corroborated by ZINDO-calculated spectra comparing linear polysilane, network polysilyne, crystalline cluster, and amorphous cluster structures, which showed respectively lowest absorption transition energies of 5.38 eV (230.4 nm), 4.60eV (269.5nm), 4.57eV (271.2nm), and 2.46eV (503.9nm), as shown in Figure 57.362... 

Figure 1 shows scanning electron microscopy (SEM) photograph of microcrystals precipitated from C6o solution in 1,2 dichlorobenzene. The mixture of perfect crystals with the size up to 100p with submicron microcrystals and amorphous clusters represent the typical structure of precipitated fullerenes. It was found that the ratio of the crystalline and amorphous phases depends on the precipitation rate and the temperature of Cg0 solution. The higher crystalline fraction was obtained at lower-temperatures and lower rate of precipitation. 

Pt-based electrocatalysts have proven to be ideally suited to the Ap analysis primarily because of the extensive morphological characterizations (X-ray diffraction, single crystal electrochemical evaluations, UHV spectroscopies, etc.) performed over the past decades. In contrast, chalcogenide electrocatalysts are comprised of nanoscale amorphous clusters making a detailed analysis of the strac-ture/property relationships inherently difficult. In light of these considerations, we have recently applied the Ap technique to a novel mixed-phase chalcogenide electrocatalyst (RhxSy, commercially available from A-TEX, Inc). Rh Sy shows remarkable per-... 

Metallic nanopartides were deposited on ceramic and polymeric partides using ultrasound radiation. A few papers report also on the deposition of nanomaterials produced sonochemically on flat surfaces. Our attention will be devoted to spheres. In a typical reaction, commerdally available spheres of ceramic materials or polymers were introduced into a sonication bath and sonicated with the precursor of the metallic nanopartides. In the first report Ramesh et al. [43] employed the Sto-ber method [44] for the preparation of 250 nm silica spheres. These spheres were introduced into a sonication bath containing a decalin solution of Ni(CO)4. The as-deposited amorphous clusters transform to polyciystalline, nanophasic, fee nickel on heating in an inert atmosphere of argon at a temperature of 400 °C. Nitrogen adsorption measurements showed that the amorphous nickel with a high surface area undergoes a loss in surface area on crystallization. 

Charlier et al. [48] used the tight-binding model to study distorted stacking of graphene layers, termed pregraphitic or turbostratic carbon. The turbostratic structure was obtained by generating an amorphous cluster of graphene plates that... 

The impregnation of fluorine-containing gels by the acetone solution of FeCh and subsequent thermal treatment at 1200°C in air results in the formation of fluorinated Fe-containing compounds in the form of nanosize amorphous clusters, dispersed in the matrix of silica-like opalescence material. 

Higher crystallinity index reported Measurements, controls and/ or addition of modifying reagents and scale up are difficult to perform. Measurements, controls and scale up can be easily implemented Pellets or amorphous clusters of lower crystallinity index, highly branched BNC... 

A general appearance of Mo-rich sample does not differ much from the Ni-ilch. The TEM of typical amorphous cluster is shown in Fig. 8.35a. In the small crystalline areas (xl), traces of MoNi4 and M0O3 phases were detected, and their diffraction... 

Domain size of API in intimately mixed ASD ( < 10 nm) deduced using Ti relaxation times (amorphous cluster versus molecular dispersion) ... 

The specimen is composed of large amorphous clusters containing nanosized crystalline particles. Fig. 5.61 shows a TEM image of an amorphous particle (a) and the corresponding SAED pattern (b). 

Fig. 6.2 Radial (left) and angular (right) distributions of the amorphous cluster obtained by WWW (red), and equilibrated using Tersoff (green), EDIP [21] (blue) and StiUinger-Weber (magenta) potentials...

Theoretical spectra were obtained by using SiC clusters with different diameters as shown in O Fig. 18-9. Additionally, the calculations for clusters with fixed diameter at 1.1 nm and different structures cubic, hexagonal, and amorphous were performed (O Pig. 18-10). The computed VDOS spectra for amorphous clusters seem closer to the experimental curves obtained on the as-formed nanopowders (O Figs. 18-7 and O 18-8). This suggests that the main contribution to the experimental VDOS comes from the amorphous fractions ofthe nanoparticles in agreement with the structural NMR characterizations. 

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