Search results for "SCOPE"
showing 10 items of 2420 documents
SNOM study of ferroelectric domains in doped LiNbO3 crystals
2009
Abstract This work shows a study of the periodic ferroelectric domains formed in LiNbO3 crystals doped with rare earths by means of scanning near field optical microscopy (SNOM) technique. It has been observed periodic structures associated with ferroelectric domains with an unexpected high value of the optical contrast working under reflectance SNOM mode. From Raman-Nath diffraction patterns, a refractive index modulation of Δ n ∼ 1 0 − 4 has been calculated. These results were correlated with the ferroelectric periodic domains obtained by the SNOM technique. A light waveguide effects along the ferroelectric domains is suggested to explain the high reflectance contrast observed in SNOM exp…
Growth and characterization of Mg 1‐x Cd x O thin films
2016
In this paper, we study the growth of thin films of the Mg1–xCdxO alloy in the Mg-rich range of compositions by using the metal organic chemical vapour deposition (MOCVD) method at low pressure. X-ray diffraction (XRD) has been used to analyse the compound formation and the progressive incorporation of Cd2+ ions into the cubic MgO lattice. Both, layers with a single-cubic phase of Mg1–xCdxO and layers with a phase separation, where Cd1–xMgxO and Mg1–xCdxO coexist, have been studied. Finally, a morphological study of the layers has been carried out by using scanning electron microscopy (SEM) and the layers' composition has been measured by energy dispersive X-ray analysis (EDX). (© 2016 WILE…
Characterization of Dielectric Anomaly in Solid Solution Based on BaTiO3
2011
The influence of Zr doping on a structure and dielectric properties of Ba0.8Sr0.2TiO3 were studied. For this purpose Ba0.8Sr0.2Ti0.75Zr0.25O3 ceramics were obtained by a conventional method and were determined by an X-ray diffraction (XRD) and scanning electron microscopy (SEM) for crystallographic, surface morphological and compositional studies. The temperature and frequency dependence of dielectric permittivity were studied in the temperature range from 150 to 500 K and the frequency between 20 Hz and 1000000 Hz. The thermal behavior of the Ba0.8Sr0.2Ti0.75Zr0.25O3 ceramics were also studied using Differential Scanning Calorimetry. A diffusivity coefficient γ was calculated.
X-ray diffraction line-broadening study on two vibrating, dry-milling procedures in kaolinites
2009
Due to the great technological importance of the microstructure of kaolinite, characterizing its evolution during dry milling of kaolin and analyzing the microstructural information obtained from different methods were the main aims of this work. The microstructural alteration of kaolinite is evaluated by X-ray diffraction and electron microscopy methods, comparing the results obtained and analyzing the correlations between them. The Warren-Averbach and Voigt-function methods of X-ray diffraction microstructural analysis have been applied successfully to the study of the effects of two different, vibrating-cup dry-milling configurations in the microstructure of kaolinite from the reflection…
Gas sensing properties of Zn-doped p-type nickel ferrite
2012
Abstract The influence of zinc ion to the NiFe2O4 p-type semiconductor gas response characteristics is demonstrated. For characterization of gas sensor material, synthesized by sol–gel auto combustion method, X-ray diffraction (XRD), scanning electron microscopy (SEM), DC resistance and impedance spectroscopy (IS) measurements were employed. The response change of Zn doped nickel ferrite is related to the interruption of hole hopping between nickel ions. This was improved by change of conductivity type with temperature and gas exposure.
Preparation and Electric Properties of Barium Zirconium Titanate Ceramic
2015
The relaxor behavior of barium zirconium titanate ceramics BaZr0.35Ti0.65O3 prepared by a conventional sintering process was investigated. The synthesized material was determined by an X-ray diffraction and scanning electron microscopy. Based on performed studies, the BaZr0.35Ti0.65O3 ceramic material has been identified as canonical relaxor, related to the Ti-rich polar regions. The freezing temperature Tf and activation energy Ea are calculated from the Vogel-Fulcher relationship.
CuInS2 Films for Photovoltaic Applications Deposited by a Low-Cost Method.
2006
We report an atmospheric-pressure deposition method for preparing well-adhered and compact CuInS 2 films. The precursor film is obtained by a solution-coating technique and is subjected to a low-cost and safe one-step reduction-sulfurization treatment. A maximum thickness of 300 nm is achieved per layer, and up to three layers were sulfurized at a time. The obtained films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and visible-near-infrared (vis-NIR) spectrophotometry.
Investigating the performance of reconstruction methods used in structured illumination microscopy as a function of the illumination pattern's modula…
2016
Surpassing the resolution of optical microscopy defined by the Abbe diffraction limit, while simultaneously achieving optical sectioning, is a challenging problem particularly for live cell imaging of thick samples. Among a few developing techniques, structured illumination microscopy (SIM) addresses this challenge by imposing higher frequency information into the observable frequency band confined by the optical transfer function (OTF) of a conventional microscope either doubling the spatial resolution or filling the missing cone based on the spatial frequency of the pattern when the patterned illumination is two-dimensional. Standard reconstruction methods for SIM decompose the low and hi…
Structural investigation of four-centre photopolymerisation of bis-phthalamic bis-chalcone derivative in the crystalline state
1997
By combining the results obtained from an electron diffraction tilting series with solid state NMR and powder X-ray diffraction, it was possible to determine the unit cell parameters and space group of BPABC crystals grown from DMAA solution both before and after irradiation. Subsequently semi-empirical quantum mechanical and packing energy calculations led to a model structure which agreed well with all the electron diffraction data and thus provided insight into the cross-linking mechanism. © 1997 John Wiley & Sons Ltd.
Influence of mechanoactivation on the adhesion and mechanical properties of metal/oxide interfaces
2005
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, In/glass, Mg/SiO2 etc.) are reported. Interfaces were formed at plastic deformation of metal on the oxide surface at room temperature. Structure, composition, and micromechanical properties of the interfaces are studied by AFM, X-ray diffraction, SIMS, electron, optical microscopy, and precision microindentation. A noticeable adhesion is observed in the regions of maximum shear strain in case of metals with low oxide formation energy. Formation of a reaction zone with oxygen concentration gradient is detected in which the metal near the interface hardens. The effect of mechanoactivation is conside…