Materials Literature
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Novel B 3 CN 3 fibres with a special structure have been synthesized by a pyrolysis process. High-resolution TEM analysis shows that the as-prepared B 3 CN 3 fibres can be described as a nanofibre-interweaved network. Strong photoluminescence at 370 nm and 700 nm from the as-prepared B 3 CN 3 fibres are observed at ro…
Fatigue behaviour of Pb(Zr 0.45 Ti 0.55 )O 3 (PZT) thin films on Pt (111) /Ti/SiO 2 /Si (100) substrates with PbZrO 3 (PZ) buffer layers were investigated. Two different buffer layer configurations were studied: bottom- and top-only buffer layers. The PZ buffer layers were obtained by RF magnetron sputtering of a loos…
In order to study the applicability of EMAR (electromagnetic acoustic resonance) method to non-destructive hydrogen level assessment in fuel spacer bands at pool side, an ultrasonic transmitter and receiver together with an EMAT (electromagnetic transducer) were used. Unirradiated Zircaloy-2 thin plates were hydrogen…
Dielectric permittivity of PMN and PMN with 10% PT single crystals was measured in the frequency range from 20 Hz to 3 GHz. Dielectric dispersion was observed in all investigated frequency range. From the frequency dependence of the real and imaginary parts of dielectric permittvity, the distribution of relaxation tim…
Purpose Proposes to investigate preparation of amorphous silica via precipitation reaction from aqueous solution of sodium metasilicate and hydrochloric acid in emulsion medium, focusing on determination to optimise the dispersive and morphological properties of silicas studied. Design/methodology/approach The silicas…
Zirconium alloy sheets were prepared with varying Fe, Cr and Ni systematically. The corrosion and hydrogen pickup property were estimated in steam at 673 K, in water at 633 K and in super critical water at 673 K. The effect of the SPP and the oxide film on the hydrogen pick-up was studied from the hydrogen pick-up rou…
Cross-linked urethane/urea membranes with two soft segments were prepared by extending a poly(propylene oxide) based tri-isocyanate-terminated prepolymer (PUR) with polybutadiene diol (PBDO). The ratio of prepolymer and polybutadiene diol was varied to yield cross-linked membranes with different compositions, exhibiti…
A study of the microdynamics of supercooled liquids and glasses is executed through calculations of the dynamic structure factor S(k, θ). The theory developed on the basis of a self-consistent approach in the framework of the memory function formalism is applied to define the frequency spectra (m/k B T)S(k, θ) of supe…
Brazil has played an important role in the development and use of resonance Raman spectroscopy as a powerful characterization tool for materials science. Here we present a short history of Raman scattering research in Brazil, highlighting the important contributions to the field coming from Brazilian researchers in th…
An analysis of the microstructure of nanocrystalline magnesium oxide produced by thermal decomposition of magnesium oxalate, in the temperature range 500 °C–1200 °C, is described. The study is based on diffraction line broadening analysis carried out with the integral breadth (Langford) and Fourier methods, combined w…
We present a description of the effect of the surface roughness on the energy straggling associated to the energy loss distributions of protons transmitted through a self supported metallic thin foil. For this purpose we prepared a polycrystalline gold thin films using the standard sputtering method with different dep…
The RANNS code analyzes behavior of a single fuel rod in reactivity-initiated accident (RIA) conditions. The code has two types of mechanical model; one-dimensional deformation model for each axial segment length of rod, and newly-developed two-dimensional local deformation model for one pellet length. Analyses were p…
The Raman spectra of carbon nanotubes (CNTs) formed on a 6H–SiC(0001) C-face substrate by surface decomposition were acquired using a 1064 nm Nd:YAG laser as the excitation source. Intense radial-breathing-mode Raman bands were successfully detected under resonant excitation from CNTs formed by the surface decompositi…
Abstract New composite electroactive materials containing conducting polymers were elaborated by oxidative polymerization of aniline and pyrrole onto porous poly(ethylene) films. The morphology of the conducting phase on the surface of the composites was investigated by scanning electron microscopy. The influence of p…
We present a theoretical description of the excitonic giant Zeeman effect observed in wide gap diluted magnetic semiconductors (Zn,Co)O and (Ga,Mn)N. In these materials, A and B excitons present quite complex energy shifts and change of oscillator strengths under magnetic field. These features can be well reproduced u…
The synthesis and the characterization of mesostructured silica doped with acidic acyl‐hydroxy‐pyrazoles like extractants are described. The extractants have either a single chelating site, 1‐phenyl‐3‐methyl‐4‐stearoyl‐5‐hydroxy‐pyrazole (HPMSP), or two chelating sites, 1,12‐bis(1′‐phenyl‐3′‐methyl‐5′‐hydroxy‐4′‐pyraz…
Purpose Aims to analyse the stress distribution in a circular flexible sheet. Part II verifies the theory with experimental work. Design/methodology/approach The investigation includes analysing the stress distribution in a circular flexible sheet clamped around its circumference under an externally applied force by a…
A study was made on the temperature behavior of the main piezoelectric parameters, namely the electromechanical coupling factor kp, the mechanical quality factor Qm, the dielectric permittivity (real and imaginary part), the loss tangent tg and the piezoelectric charge constants d33and d31of a soft type piezoelectric…
An electromagnetic dynamic plasticating extruder, invented by the authors, was used to prepare isotactic polypropylene (PP) sheets. Tensile and impact tests show that the extruded samples can simultaneously be reinforced and toughened along the flow and transverse directions in a moderate frequency and amplitude range…
Homologous series of liquid crystalline azoesters and azomethine esters consisting of a (S)‐1‐methylpropyl group attached in one of the terminal positions have been synthesized and thermally characterized. All twenty‐four derivatives from both series, namely, the 4‐(4‐n‐alkoxybenzoyloxy)‐4′‐1‐(S)‐methylpropylazobenzen…