Search results for "FLE"
showing 10 items of 3517 documents
Scolecite, Part I: Refinement of high-order data, separation of internal and external vibrational amplitudes from displacement parameters
1997
A single crystal of scolecite, CaAl2Si3O10· 3H2O, was studied by X-ray diffraction methods at room temperature. The intensities were measured with MoKα radiation (λ=0.71069 A) in a complete sphere of reflection up to sinθ/λ=0.9 A−1. The structure was refined in the pseudo-orthorhombic setting of space group F1d1 instead of the conventional setting Cc for better comparison with natrolite (Fdd2). The cell parameters are: a=18.502(1) A, b=18.974(2) A, c=6.525(1) A, β=90.615(7)°, V=2290.6(3) A3, Z=8. A refinement of high-order diffraction data yielded residuals of R(F)=0.9%, R w (F)=0.9%, GoF=1.73 for 1831 high-angle reflections (0.7≤sinθ/λ≤0.9 A−1) and R(F)=1.2%, R w (F)=1.4%, GoF=3.22 for all…
Preparation of superconducting thin films of UNiAl
2005
Abstract Epitaxial thin films of the unconventional heavy fermion superconductor UNi 2 Al 3 we prepared by coevaporation of the elementary components in a molecular beam epitaxy system (MBE). The phase purity and structural quality of the films deposited on (0 1 0)- or (1 1 2)-oriented YAlO 3 substrates were studied by X-ray diffraction and RHEED. The observed R ( T ) behavior is consistent with data obtained from bulk samples and proves the purity of the films. Superconductivity was found with transition temperature T c =0.97 K.
Investigation of AC Electrical Properties of MXene-PCL Nanocomposites for Application in Small and Medium Power Generation
2021
The paper examined Ti3C2Tx MXene (T—OH, Cl or F), which is prepared by etching a layered ternary carbide Ti3AlC2 (312 MAX-phase) precursor and deposited on a polycaprolactone (PCL) electrospun membrane (MXene-PCL nanocomposite). X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) indicates that the obtained material is pure Ti3C2 MXene. SEM of the PCL-MXene composite demonstrate random Ti3C2 distribution over the nanoporous membrane. Results of capacitance, inductance, and phase shift angle studies of the MXene-PCL nanocomposite are presented. It was found that the frequency dependence of the capacitance exhibited a clear sharp minima in the frequency range of 50 Hz to o…
Highly angular resolving beam separator based on total internal reflection
2019
We present an optical element for the separation of superimposed beams that only differ in angle. The beams are angularly resolved and separated by total internal reflection at an air gap between two prisms. As a showcase application, we demonstrate the separation of superimposed beams of different diffraction orders directly behind acousto-optic modulators for an operating wavelength of 800 nm. The wavelength as well as the component size can easily be adapted to meet the requirements of a wide variety of applications. The presented optical element allows one to reduce the lengths of beam paths and thus to decrease laser system size and complexity.
Determinant role of the edges in defining surface plasmon propagation in stripe waveguides and tapered concentrators
2012
International audience; In this paper, we experimentally show the effect of waveguide discontinuity on the propagation of the surface plasmon in metal stripes and tapered terminations. Dual-plane leakage microscopy and near-field microscopy were performed on Au stripes with varied widths to imag29e the surface plasmon intensity distribution in real and reciprocal spaces. We unambiguously demonstrate that edge diffraction is the limiting process determining the cutoff conditions of the surface plasmon mode. Finally, we determine the optimal tapered geometry leading to the highest transmission.
Treatment of grazing-incidence small-angle X-ray scattering data taken above the critical angle
2001
The equations taking into account refraction at the sample surface in grazing-incidence small-angle X-ray scattering (GISAXS) when the angle between the incoming beam and the sample surface is slightly larger than the critical angle are derived and discussed. It is demonstrated that the refraction of both the incoming and the scattered beam at the sample surface affects the GISAXS pattern and that, when a planar bidimensional detector perpendicular to the incoming beam is used, the effect depends on the azimuthal detector angle. The smearing of the pattern depending on the size of the illuminated sample area in grazing incidence is estimated by simulations with Cauchy functions of different…
Applications of automated diffraction tomography (ADT) on nanocrystalline porous materials
2013
Abstract Many porous materials, both inorganic and hybrid organic–inorganic, can only be synthesized as nanocrystals. X-ray powder diffraction delivers one-dimensional data from the overall sample and is therefore often limited by peak overlap at low or medium resolution and by peak broadening. Thus, structure solution of materials with large unit cells and low symmetry, disorder or pseudosymmetry, or available only in polyphasic systems, turns out to be problematic or even impossible. Electron diffraction allows collecting three-dimensional structure information from nanocrystalline materials, but is traditionally biased by low completeness of the diffraction data, dynamical scattering and…
Application of delta recycling to electron automated diffraction tomography data from inorganic crystalline nanovolumes
2013
δ Recycling is a simple procedure for directly extracting phase information from Patterson-type functions [Rius (2012). Acta Cryst. A68, 399-400]. This new phasing method has a clear theoretical basis and was developed with ideal single-crystal X-ray diffraction data. On the other hand, introduction of the automated diffraction tomography (ADT) technique has represented a significant advance in electron diffraction data collection [Kolb et al. (2007). Ultramicroscopy, 107, 507-513]. When combined with precession electron diffraction, it delivers quasi-kinematical intensity data even for complex inorganic compounds, so that single-crystal diffraction data of nanometric volumes are now availa…
The Phases of Phosphatidyl Ethanolamine Monolayers
1992
For the first time phospholipid monolayers at the air/water interface have been studied by X-ray diffraction and reflection along the whole isotherm from the isotropic fluid to the ordered phases [1]. The model used to analyze the data — and the accuracy of the parameters deduced — were tested by comparing the results obtained with two lipids having the same head group but different chain lengths.
Structure analysis of titanate nanorods by automated electron diffraction tomography
2011
A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically …