Materials Literature
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Kratzbürstig: Beschrieben wird die oberflächeninitiierte Polymerisation (SIP) von Methylmethacrylat (MMA) und Styrol (S) an den Oberflächen von mehrwandigen Kohlenstoffnanoröhrchen (MWNTs) mit einem kovalent gebundenen Atomtransferradikalstarter, der durch Propfpolymerisation an den MWNT-Oberflächen fixiert wurde (sie…
Abstract The influence of low contents of a liquid crystalline polymer on the crystallization and melting behavior of isotactic polypropylene (iPP) was investigated using electron and optical microscopy, differential scanning calorimetry, and X‐ray diffraction. In pure iPP, the α modification was found, whereas for iP…
Photoluminescence (PL) measurements have been carried out on Si quantum dots (QDs) with sizes of 2–4 nm embedded in Si oxide films. Conspicuous multiple PL peaks separated in energy by up to 104 meV are observed and attributed to optical transitions in discrete energy levels of Si QDs. A band-mixing model of direct an…
Lattice dynamics and dielectric relaxation phenomena of $({\mathrm{Sr}}_{1\ensuremath{-}1.5\mathrm{x}}{\mathrm{Bi}}_{\mathrm{x}}){\mathrm{TiO}}_{3}$ ceramics with $x=0.0067--0.133$ were studied in the temperature range of 10--400 K. The polar ${\mathrm{TO}}_{1}$ soft mode in the IR spectra is strongly stiffened by Bi…
Thickness-dependent strain relaxation and its role on exciton resonance energies of epitaxial ZnO layers grown on 6H-SiC substrates have been studied. The magnitudes of strain were determined experimentally by x-ray diffraction measurements. The strain ratios under biaxial stresses (Δc/c0)/(Δa/a0) of epitaxial ZnO lay…
The giant single‐molecule {Mn 84 } (diameter ca. 4.3 nm), bridges the molecular (bottom‐up) and classical (top‐down) approaches to nanoscale magnetic materials. The cover shows the {Mn 84 } toroidal molecule as a bridge between the quantum ({Mn 4 } and {Mn 12 } clusters) and classical (a Co nanoparticle) worlds of mag…
CD spectroscopic study of the secondary structure of partly adenylylated glutamine synthetase (GS) of the bacterium Azospirillum brasilense showed both the native and cation-free (EDTA-treated) enzyme to be highly structured (58 and 49% as alpha-helices, 10 and 20% as beta-structure, respectively). Mg(2+), Mn(2+), or…
A novel crystal growth method has been developed to grow single crystals of magnesium carbonate from molten sodium. Single crystals of magnesium carbonate with a size up to 1.5 mm were grown at 550 °C in a closed vessel consisting of an appropriate amount of magnesium carbonate powder, metallic sodium, and carbon tetr…
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…