Materials Literature
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Self-assembly of diblock copolymers having a crystallizable block can yield particles of complex shapes. Here, particles have been obtained by mixing two solutions of poly( l -lactide)−poly(ε-caprolactone) and poly( d -lactide)−poly(ε-caprolactone) diblock copolymers, in a good solvent of polycaprolactone. We have pro…
The mechanism and origin of asymmetric induction in the Mn(III)(salen)-catalyzed epoxidation by peracetic acid have been elucidated by the density functional [Becke three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP)] method in two different regimes: with and without an axial l…
TiO 2 : Co films have been grown in the rutile phase under varying oxygen growth pressures. Detailed microstructural analysis using transmission electron microscopy shows that reduced growth pressure increases the presence of cobalt clusters. The resistivity is found to follow a log(ρ)∼T−1/2 dependence over a wide tem…
In this letter, we report fluctuation microscopy studies of medium-range ordering in amorphous diamond-like carbon films and the effect of annealing on this ordering. Annealed and unannealed diamond-like carbon films have almost identical short-range order. Our fluctuation microscopy results, however, indicate the pre…
Ins Blaue: Die hier vorgestellten (CdS)ZnS-Nanokristalle für Displays zeichnen sich durch eine blaue Lumineszenz im engen Bereich zwischen 460 und 480 nm (Halbwertsbreite≤28 nm; siehe Bild) mit einer Quanteneffizienz von 20–30 % aus. Nach Integrierung in dünnen organischen Filmen kann blaue Elektrolumineszenz dieser K…
Mapping proton transfer: Disorder and proton transfer are important aspects in many hydrogen bonds. These phenomena can affect physical properties and the design of intermolecular interactions for crystal engineering. Variable-temperature X-ray diffraction (see Fourier map) is shown to be a highly appropriate tool for…
In this work, fatigue failure mechanisms of single-walled carbon nanotube (SWCNT) bundles embedded in epoxy matrix under repeated tensile load were studied. Observed damage and failure modes include: (1) splitting of SWCNT bundles, (2) kink formation and subsequent failure in SWCNTs, and (3) fracture of SWCNT bundles.…
Sub 50-nm-high BaTiO3 epitaxial nanostructures were fabricated into well-ordered arrays on SrTiO3:Nb (001) single-crystal substrates using pulsed laser deposition through monolayer masks of monodisperse latex spheres (1 or 0.5 μm) and postdeposition annealing. Imprint was investigated in nanostructures of various dime…
Room temperature ferromagnetic Fe- and Ni-doped TiO2 thin films were grown by the laser ablation on both LaAlO3 and SrTiO3 substrates. Most of the films are pure anatase, and only the films of Ni content of 3.6% and 4.6% are rutile. Films on LaAlO3 substrates are more crystallized than films on SrTiO3 substrates resul…
The perovskite-based oxide ${\mathrm{Y}}_{0.33}{\mathrm{Sr}}_{0.67}{\mathrm{CoO}}_{2.79}$ has been magnetically and structurally characterized. The material shows a unit cell of $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}4$ simple perovskite cubes with space group $I4/mmm.$ This is a differ…
Using a synchrotron radiation source and a diamond anvil cell, we measured the pressure dependence of the lattice parameters of a polycrystalline Ti3Si0.5Ge0.5C2 sample. Up to a pressure of 53 GPa, no phase transformations were observed. As for the isostructural hexagonal Ti3SiC2, the compressibility along the c axis…
Magnetoelectrics, characterized by simultaneous ferroelectric and magnetic ordering, have potential applications in information storage, sensors, etc. However, there are very few materials exhibiting the coexistence of ferroelectric and ferromagnetic ordering at room temperature. Hence, in normal practice, desired mag…
The thermoreversible fcc-bcc transition in concentrated block copolymer micellar solutions is shown to be driven by decreases in the aggregation number as the solvent penetrates the core, leading to a softer intermicelle potential. Small-angle neutron scattering measurements in a dilute solution are used to quantify t…
The structure of the tenfold surface of decagonal Al-Ni-Co was studied using low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). The surface region is a relaxed truncated bulk structure, having the same composition as the bulk. The outermost layer spacing is contracted by 10% relative to th…
Lattice yield to tension within practical time and temperatures is determined by the probability of defect formation. Its rate in nanotubes depends in turn on the transition state and activation barrier for the Stone–Wales bond rotations. Systematic ab initio computations of the barriers for the tubes of various symme…
The $({\mathrm{Li}}_{x}{\mathrm{Na}}_{1\ensuremath{-}x}){\mathrm{NbO}}_{3}$ perovskite solid solutions are investigated using synchrotron x-ray diffraction and Raman spectroscopy in order to clarify the structural changes in the concentration range $0<~x<~0.145$ at room temperature. The orthorhombic antiferroele…
The mechanical relaxation of metallic Zr46.75Ti8.25Cu7.5Ni10Be27.5 supercooled liquid has been measured by dynamic mechanical analysis. The relaxation behaviors are found to fit well the Kohlrausch–Williams–Watts equation in time domain as well as the Havriliak–Negami equation in frequency domain. Characteristic quant…
Structural phase transformation from multiwalled carbon nanotubes to nanocrystalline diamond by hydrogen plasma post-treatment was carried out. Ultrahigh equivalent diamond nucleation density above 1011 nuclei/cm2 was easily obtained. The diamond formation and growth mechanism was proposed to be the consequence of the…
Abstract A new method for the synthesis of exfoliated graphite and polyaniline (PANI)/graphite nanocomposites was developed. Exfoliated graphite nanosheets were prepared through the microwave irradiation and sonication of synthesized expandable graphite. The nanocomposites were fabricated via the in situ polymerizatio…
Heterogeneous deacetylation of alpha- and beta-chitins from shrimp shells and squid pens were comparatively studied. Each deacetylated sample, recovered after neutralization, was fractionated according to a water-soluble and insoluble fraction (pH 8.5). The systematic study of DAs, crystallinity changes, and distribut…