Search results for "FLE"
showing 10 items of 3517 documents
Three‐Component Self‐Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host–Guest Assemblies
2021
Angewandte Chemie / International edition 60(21), 12132 - 12142 (2021). doi:10.1002/anie.202103178
Strain‐induced compression of smectic layers in free‐standing liquid crystalline elastomer films
2005
The deformation of oriented smectic liquid crystal elastomer films with smectic layers parallel to the film surface was studied using optical reflectometry and small angle X‐ray diffraction. Reflectometry data show that in the chosen material, in‐plane strain causes a change in the optical thickness of the free‐standing films. Small angle X‐ray scattering was used to explore the molecular origin of this effect. The X‐ray scattering data confirm that the change in optical thickness originates from the compression of the individual smectic layers. The measured Poisson ratio in the smectic A and C* phases is close to ½, in contrast to the smectic elastomers investigated earlier by Nishikawa et…
Site-specific atomic order and band structure tailoring in the diluted magnetic semiconductor (In,Ga,Mn)As
2021
Physical review / B 103(7), 075107 (1-13) (2021). doi:10.1103/PhysRevB.103.075107
Raman scattering and infrared reflectivity in [(InP)5(In0.49Ga0.51As)8]30 superlattices
2000
6 páginas, 6 figuras, 1 tabla.
X-ray diffraction microstructure analysis of mullite, quartz and corundum in porcelain insulators
2005
Abstract The X-ray diffraction microstructure analysis has been performed on commercial samples of the silica and alumina porcelain insulators obtained at 1300 °C, with the same time of firing. The study was carried out on mullite, corundum and quartz by applying several integral breadth methods (i.e. the Williamson–Hall analysis, the Langford method and the Halder–Wagner approximation) and the Fourier analysis (Warren–Averbach method). The apparent crystallite sizes determined for the mullite are direction-dependent (anisotropic) and within each group of samples, on average, the greatest values are obtained along the direction [0 0 1]. With regard to the microstructure of the corundum and …
High resolution X-ray diffraction, X-ray multiple diffraction and cathodoluminescence as combined tools for the characterization of substrates for ep…
2013
The goal of this work is to show the capability of X-ray multiple diffraction (XRMD) to be used in combination with high resolution X-ray diffraction (HRXRD) and cathodoluminescence (CL) as an easy and simple methodology to determine structural and surface defect-related characteristics of samples that could be used as substrates for epitaxial growth. For this study ZnO {0001}-oriented samples have been used in view of their use as substrates for homoepitaxy. The miscut and bending of the samples have been analyzed by measuring the position of the X-ray diffraction peaks. The presence of multiple crystallographic domains and their characteristics have been studied by HRXRD (from the allowed…
Diffraction by fractal metallic supergratings.
2007
The reflectance of corrugated surfaces with a fractal distribution of grooves is investigated. Triadic and polyadic Cantor fractal distributions are considered, and the reflected intensity is compared with that of the corresponding periodic structure. The self-similarity property of the response is analyzed when varying the depth of the grooves and the lacunarity parameter. The results confirm that the response is self-similar for the whole range of depths considered, and this property is also maintained for all values of the lacunarity parameter. © 2007 Optical Society of America. Fil: Skigin, Diana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación…
<title>Investigation of As<formula><inf><roman>2</roman></inf></formula>S<formula><inf><roma…
2008
We have performed the investigation of dot matrix holographic recording in amorphous As2S3 chalcogenide films with different thickness on Al coated glass substrates. The control over the interference minimum of reflection during the evaporation process allowed obtaining As2S3-Al system with a minimum value of initial reflection in defined spectral region. The investigation of dependence of diffraction efficiency of holographic recording on both film thickness and initial conditions of reflectivity in the system was performed. The main advantage of this type of system is the possibility to increase optical sensitivity of material in predefined spectrum region for phase hologram recording.© (…
Enhanced diffraction of light in GaAs microcavities
1995
We theoretically analyze the diffraction of light by gratings that are photogenerated in Fabry–Perot microcavities. The coupled-wave theory of volume gratings is combined with appropriate boundary conditions to yield expressions for the diffraction efficiency. Multiple round trips within the cavity are seen to increase the effective grating thickness and therefore the efficiency. Numerical calculations specific to GaAs microcavities show that the diffraction efficiency can be enhanced by more than 2 orders of magnitude at the resonant wavelengths.
Electron diffraction, X-ray powder diffraction and pair-distribution-function analyses to determine the crystal structures of Pigment Yellow 213, C23…
2009
The crystal structure of the nanocrystalline alpha phase of Pigment Yellow 213 (P.Y. 213) was solved by a combination of single-crystal electron diffraction and X-ray powder diffraction, despite the poor crystallinity of the material. The molecules form an efficient dense packing, which explains the observed insolubility and weather fastness of the pigment. The pair-distribution function (PDF) of the alpha phase is consistent with the determined crystal structure. The beta phase of P.Y. 213 shows even lower crystal quality, so extracting any structural information directly from the diffraction data is not possible. PDF analysis indicates the beta phase to have a columnar structure with a si…