Bragg diffraction spectroscopy

Three-dimensional opal-VO based photonic crystals were prepared by the chemical bath deposition technique. The x-ray diffraction and Raman spectroscopy confirm the crystalline perfection of VO2 impregnated into synthetic opal pores. It is shown from the optical reflectivity measurements that the photonic bandgap of the opal-V02 based photonic crystals composite is governed by the phase transition in VO2. The shift of Bragg diffraction spectra under the pulsed (10 ns) illumination of YAG.Nd laser has been also observed in the opal-VO2 composites. 

In the last decade the electroacoustic waves in colloids [37] attracted considerable attention. Electrically induced concentration fluctuations were detected by means of different experimental techniques. The Bragg diffraction technique was used to analyze the concentration gradients induced in colloidal crystals by dc electric pulses [38], Density fluctuations in ac electric fields were observed with time-resolved reflection spectroscopy and transmitted light spectroscopy [39,40]. The conventional light scattering was also applied to detect the induced translation... 

MM Carrabba, KM Spencer, C Rich, D Rauh. The utilization of a holographic bragg diffraction filter for Rayleigh line rejection in Raman spectroscopy. Appl Spectrosc 44 1558-1561, 1990. 

The structures of iron oxides have been determined principally by single crystal X-ray diffraction or neutron diffraction with supplementary information coming from infrared spectroscopy, electron diffraction and high resolution electron microscopy. A few years after the first successful application of X-ray diffraction to crystal structure determination, this technique was used to establish the major features of the structures of magnetite (Bragg, 1915 Nishikawa, 1915) and hematite (Bragg Bragg, 1918). 

The study by low-angle X-ray diffraction of these mesophases provides X-ray patterns exhibiting a set of sharp lines with Bragg spadngs characteristic of a layered structure. This lamellar structure results from the superposition of plane, parallel, and equidistant sheets each sheet contains two layers one of thickness dA formed by the carbohydrate blocks, the other of thickness dB formed by the polypeptide blocks, there is a partition of the solvent between the two blocks 70% DMSO is localized in the carbohydrate layer284. Furthermore, the polypeptide chains are in a a-helix conformation as is demonstrated by infrared spectroscopy and X-ray diffraction and are oriented perpendicular to the plane of the sheets and assembled in a bidimensional hexagonal lattice as is revealed by X-rays284. ... 

Attempts to verify the above volume diffusion mechanism experimentally included X-ray and electron diffraction experiments with electrodes that were corroded at > Ec, as well as investigations by positron annihilation spectroscopy (PAS). In the former case, the occurrence of broadened diffraction lines at Bragg angles between those of the bulk alloy and the pure, noble component was taken as a confirmation of the volume diffusion mechanism [54, 120, 131]. More direct evidence was obtained from the PAS experiments with dezincified brass, where experimental positron Kfetimes correlated well with calculated values in vacancies or vacancy aggregates [78-80]. On the other hand, it has been objected that Eq. (20) predicts a dependence of the current density, which is in contradiction to many experimental results. It has been shown, however, that this particular problem may... 

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