Materials Literature
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Abstract This article describes the homopolymerization of isocyanatoethyl methacrylate (IEM) and its copolymerization with methyl methacrylate (MMA) in acetonitrile in the presence of 2,2′‐azobisisobutyronitrile. The constant characteristic of IEM polymerizability ( k p 2 / k te = 128 × 10 −3 L mol −1 s −1 , where k p…
Nanocrystallization is known to yield several improvements for the storage and uptake rate of hydrogen in solids. Usually this process is achieved by ball milling to produce a nanopowders. However, handling of these powders is risky and difficult, and there is also a high risk of introducing impurities into the storag…
Inelastic deformation behavior of the rhombohedral La0.6Sr0.4FeO3 perovskite is reported. Such behavior is very similar to the ferroelastic deformation of LaCoO3 or lead zirconate titanate perovskites, except that no twin structure was found to exist in La0.6Sr0.4FeO3. The possible mechanisms responsible for such nonl…
We studied the second order optical nonlinearity of aluminum nitride films grown by sputtering onto silicon substrates. The crystalline properties of the films were investigated by x-ray diffraction measurements. Preliminary linear optical characterization of the films was carried out by spectrophotometric optical ref…
The spin configuration and magnetostrictive properties of TbxDy0.7−xPr0.3(Fe0.9B0.1)1.93 (0.10⩽x⩽0.28) Laves compounds are investigated. The spin phase diagram for the compounds is constructed to illustrate both the composition dependence of the Curie point TC and spin reorientation temperature TSR and the arrangement…
We present the detection of the shape-specific conformation of DNA based on the fluorescence resonance energy transfer (FRET) by using a novel flexible water-soluble cationic conjugated polymer (CCP). The flexible backbone of CCP has more conformational freedom with the potential to be responsive to analyte shape by e…
A correlated Gaussian lattice-parameter distribution of an ensemble of crystals, as leading to line broadening in the course of powder diffraction, can be associated with a correlated Gaussian microstrain distribution. The latter can be described in terms of a fourth-rank covariance tensor containing as its 81 compone…
Technically pure aluminium was subjected to three passes by the process of hydrostatic extrusion (HE) to a true strain of 3.8. TEM observations of the microstructure revealed that the first pass of the process refined the grains to 0.6 μm, but the mean grain size remains unaffected by further strain. The microstructur…
Ba ( Zr 0.25 Ti 0.75 ) O 3 (BZT) and (Ba0.6Sr0.4)TiO3 (BST) ceramics were prepared as typical samples of lead-free relaxors and ferroelectrics with the diffuse phase transition, respectively. A suitable measurement technique using microplanar electrode and electromagnetic field analysis was developed to measure the mi…
An ultra-fine grained microstructure was obtained in high purity nickel by a combination of (a) equal-channel angular pressing (ECAP) and (b) hydrostatic extrusion (HE) with a cumulative true strain of ~11.2. The resulting microstructure was examined by light and TEM microscopy. Mechanical properties have been measure…
Al-0.1Mg with a 3μm grain size was deformed in channel die plane strain compression at temperatures up to 200oC. It was found that the reduction in grain thickness was significantly less than that predicted from geometric considerations, and at larger strains, a minimum high angle grain spacing, which was equal to the…
The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is highe…
Liquid crystals are known to exhibit a reversible color change by applying a direct current electric field, if a small amount of quaternary ammonium salts is dissolved into them. Applications of such an electrochromic liquid crystal cell have been proposed as interesting laser-addressed writing and image storage devic…
Iron-9% chromium alloy of controlled purity and microstructure was helium implanted and studied using transmission electron microscopy and electron holography (EH). Fresnel imaging is compared with electron holography for a set of identical helium bubbles of size 2–4nm. Electron holography reveals that the bubbles are…
Extended x-ray absorption fine structure (EXAFS) spectroscopy was employed to study the Er coordination in polycrystalline Y2O3 thin films, which was found to dictate their photoluminescence (PL) properties. Incorporation of Er with concentrations varying from 6to14at.% was achieved by radical-enhanced atomic layer de…
The bleaching relaxation characteristics of PbS quantum dots with diameters in the range of 3.8–4.3nm synthesized in silicate and phosphate glasses have been studied under the conditions of femtosecond excitation. It has been observed that increase of pump fluence from 0.1to2.2mJ∕cm2 leads to the appearance of a secon…
Direct methods combined with direct-space refinement procedures are the standard tools for ab initio crystal structure solution of macromolecules via diffraction data collected up to atomic or quasi-atomic resolution. An entirely direct-space approach is described here: it includes an automated Patterson deconvolution…
Undoped zinc oxide (ZnO) thin films were grown on sapphire and zirconia [yttria-stabilized zirconia (YSZ)] substrate to investigate the effect of the annealing on luminescence properties. For the films grown on sapphire substrate, the electron concentration increased to 1.6×1019cm−3 as a result of in-diffusion of alum…
The Cyclic Extrusion Compression (CEC) is one of the methods of severe plastic deformation (SPD), used for producing nanomaterials. The CEC method allows materials to be deformed to arbitrarily large strains without changing the initial shape of sample. Large hydrostatic compressive stresses are exerted during deforma…
The magnetic anisotropy of the supramolecular [2 x 2] grid [Co(II)4L4]8+, with a bis(bipyridyl)-pyrimidine-based ligand L, was investigated by single-crystal magnetization measurements at low temperatures. The magnetization curves exhibit metamagnetic-like behavior and are explained by the weak-exchange limit of a min…