Materials Literature
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BiFeO 3 thin films have been prepared on Pt∕TiO2∕SiO2∕Si substrates under various oxygen pressures of 0.15–0.005Torr at a temperature of 450°C by pulsed-laser deposition. The effects of deposition pressure on their crystal structure and multiferroic properties have been investigated at room temperature. X-ray diffract…
The reaction of nanoscale diamond (ND) powder with an elemental fluorine/hydrogen mixture at temperatures varying from 150 to 470 °C resulted in the high degree of ND surface fluorination yielding a fluoro-nanodiamond with up to 8.6 at. % fluorine content. The fluoro-nanodiamond was used as a precursor for preparation…
We analyze the transmission and reflection data obtained through transfer matrix calculations on metamaterials of finite lengths, to determine their effective permittivity epsilon and permeability micro. Our study concerns metamaterial structures composed of periodic arrangements of wires, cut wires, split ring resona…
Abstract Synthetic Mg/Zn/Al‐hydrotalcites with atomic ratios of 6:0:2, 4:2:2, 2:4:2 and 0:6:2 were characterized by FT‐Raman and FT‐IR spectroscopy. ‘AlOH’ IR translation modes are observed at 419, 427, 559, 616 and 771 cm −1 with two corresponding Raman bands at 465–477 and 547–553 cm −1 . ‘MgOH’ IR translation mod…
A new family of magic cluster structures is found by genetic global optimization, whose results are confirmed by density functional calculations. These clusters are Ag-Ni and Ag-Cu nanoparticles with an inner Ni or Cu core and an Ag external shell, as experimentally observed for Ag-Ni, and present a polyicosahedral ch…
We report two different, solution-based approaches that have allowed us to process metals with melting points below 400 °C as monodispersed spherical colloids, in copious quantities, and with diameters controllable in the range of 100 to 600 nm. Bismuth was selected as a typical example to demonstrate the concepts. Th…
Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution…
ADVERTISEMENT RETURN TO ISSUEPREVCommentResponse to Comment on "Catalysis and Temperature Dependence on the Formation of ZnO Nanoparticles and of Zinc Acetate Derivatives Prepared by the Sol−Gel Route"V. Briois, M. S. Tokumoto, S. H. Pulcinelli, and C. V. SantilliView Author Information LURE, Centre Universitaire Pari…
Vanadylphthalocyanine (VOPc) thin films were prepared on Au (111) and Pt (111) substrates by molecular beam epitaxy. VOPc molecules deposited on the Au (111) substrate orientated parallel to the substrate surface, and grew epitaxially on the substrate surface whose temperature was maintained at 200°C. On the other han…
During service, steel ropes can suffer from corrosion, which can reduce their mechanical properties. This degradation is particularly important in the case of structural ropes, or barriers, for snow and rockfall protection because it is not easy to detect any significant degradation over time due to the locations of t…
In order to search for relaxor ferroelectrics or relaxor antiferroelectrics in Pb-free substances, a theoretical approach is presented for hydrogen-bonded mixed crystals under conditions similar to those for relaxor perovskite oxides. On the basis of the theory for local resonance techniques proposed by one of the pre…
The most interesting problems in the crystal chemistry of ferroelectric and antiferroelectric perovskites PbB 0.5 ′ B 0.5 ″ O3 are considered. The properties and specific features of perovskites (such as the smearing of ferroelectric phase transitions, relaxor state, ferroelectric-antiferroelectric transformations, an…
A critical review of theoretical models aiming to explain the physical properties of composites based on polymeric matrices reinforced with carbon nanotubes is presented. Attention is paid to descriptions based on molecular dynamics, continuum mechanics, and finite element analysis. It is shown that both the continuum…
Biopolímeros são polissacarídeos microbianos. O biopolímero produzido por Beijerinckia sp. 7070 possui comportamento pseudoplástico e apresenta alta viscosidade em baixas velocidades de deformação, conferindo ao polímero excelentes características de suspensão. O objetivo desse trabalho foi caracterizar o biopolímero…
Abstract The removal of spent initiator, excess initiator and unbound monomer from newly synthesized polypropylene‐graft‐maleic anhydride (PP‐g‐MA) has typically been carried out using Soxhlet extraction. Standard solvents used in the Soxhlet process are xylene, toluene, acetone or methanol. These chemicals are not on…
We study the signals from excitons and defects from the cathodoluminescence spectra (CL) of the p–/pseudo substrate sample. The CL from the p– film are determined from the variation of the CL of the sample as the voltage of the exciting electron beam increases. At the lower voltages, it probes the p– film. The CL is d…
When a nanocarbon film obtained by plasmachemical deposition is fixed between two parallel electrodes and exposed to the pulsed radiation of a Q-switched neodymium laser, a pulsed electric voltage appears between the electrodes, with the pulse shape repeating the laser pulse envelope. It is shown that the amplitude an…
Resonance energy transfer by the Förster-Dexter mechanism in a cubic crystal and in a rigid homogeneous medium is studied. The homogeneous medium is modeled using a hard-sphere fluid (HSF) radial distribution function. This distribution is more realistic than the commonly used uniform distribution with excluded volume…
ZnO nano films were deposited on p-Si(100) with different pre-deposited buffer layers by RF magnetron sputtering system under different processing conditions. The film surface morphology and crystal structure were characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The result…
This paper presents general antiplane electro‐mechanical field solutions for a piezoelectric finite wedge subjected to a pair of concentrated forces and free charges. The boundary conditions on the circular segment are considered as traction free and insulated. Using finite Mellin transform methods, the stress and ele…