Materials Literature
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We describe a catalyst-free vapor-solid synthesis of bismuth selenide (Bi2Se3) nanostructures at ambient pressure with H2 as carrier gas. The nanostructures were synthesized on glass, silicon, and mica substrates and the method yields a variety of nanostructures: nanowires, nanoribbons, nanoplatelets, and nanoflakes.…
Large values of isothermal entropy change (ΔST) and refrigerant capacity have been found in Gd5Ge2Si2−xSnx compounds. Values of the order of 20 J kg−1 K−1 for −ΔST were obtained in as-cast samples when submitted to a magnetic field variation of 2 T. First-order-magneto-structural transition is induced by the substitut…
While preexisting defects are known to act as nucleation sites for plastic deformation in shocked materials, the kinetics of the early stages of plastic yield are still poorly understood. We use atomistic simulation techniques to investigate the kinetics of plastic yield around small preexisting voids in copper single…
BiFeO3–PbTiO3 exhibits both ferroelectric and antiferromagnetic order, depending on the composition. Moderate hydrostatic pressures have been used at room temperature to transform the crystallographic phase from P4mm to R3c for the compositions 0.7BiFeO3–0.3PbTiO3 and 0.65BiFeO3–0.35PbTiO3, as determined using in-situ…
Polyamorphism and dynamical heterogeneities in network-forming liquids (SiO2, GeO2, Al2O3) at 3200 K and in a wide pressure range are investigated by molecular dynamics simulation. Results show that their structure comprises three structural phases: TO4-, TO5-, and TO6-phases (T = Si, Ge, or Al). The size of structura…
Eine Emulsionsumkehr von Wasser-in-Öl- zu Öl-in-Wasser-Emulsionen wurde durch Verwendung von Tetrahydropyranliganden erreicht, die sich leicht entschützen lassen und dadurch das ligandenfunktionalisierte, hydrophobe Nanopartikel hydrophil machen. Die Wasser-in-Öl-Emulsion wird einfach durch Senken des pH-Wertes aufgel…
VLD (vive la difference) is a novel ab initio phasing approach that is able to drive random phases to the correct values. It has been applied to small, medium and protein structures provided that the data resolution was atomic. It has never been used for non-ab initio cases in which some phase information is available…
The thermal conductivity of as-grown vertical multi-walled carbon nanotubes (CNT) bundles fabricated at low temperature (500 °C) was measured using a vertical 3ω-method. For this, CNT were selectively grown inside an oxide opening and sandwiched between two metal electrodes. The validity of the method was confirmed by…
Abstract A hydrated 5‐azotriazolyl salicylic acid of [(H3ATSA)]⋅2 H2O (1) and its CdII complex of [Cd2(H2ATSA)4]⋅13 H2O (2) have been synthesized and characterized by single‐crystal X‐ray diffraction analysis and a neutral trans‐Z‐enol form of H3ATSA and another anionic trans‐E‐enol H2ATSA− isomer have been found in 1…
Substitutional doping in graphene nanoribbons (GNRs) promises to enable specific tuning of their electronic properties. Recent work by Lv et al (2012 Nature Sci. Rep. 2 586) on large sheets of nitrogen-doped graphene determined that a highly predominant amount of nitrogen dopants (80%) are present in pairs of neighbou…
Nb2O5 thin films have been prepared using diethanolamine stabilized precursor sol and annealed at 500 degrees C. The optical, electrochemical, structural and morphological properties of Nb2O5 thin film are described. The X-ray diffraction study shows the formation of hexagonal crystal structure in the film. The presen…
Within the past decade photochromic materials, specifically dithienylethenes (DTEs), have received increased interest because of their ability to function as potential photoswitchable molecular devices and optical memory storage systems. Current research in this area has focused on incorporating organic architectures…
The Piezoelectronic Transistor (PET) has been proposed as a post-CMOS device for fast, low-power switching. In this device, the piezoresistive channel is metalized via the expansion of a relaxor piezoelectric element to turn the device on. The mixed-valence compound SmSe is a good choice of PET channel material becaus…
Uniform and highly oriented crystalline layers with submillimeter thickness have been demonstrated recently by crystallization in nonstoichiometric precursor glass, i.e., perfectly surface-crystallized glass-ceramics (PSC-GCs). Although the origin of PSC in the SrO−TiO2−SiO2 system was interpreted by the presence of S…
Effects of the tensile and compressive epitaxial strain and the crystallographic orientations on the structural and magnetic properties of (Bi0.9La0.1)2FeCrO6 (BLFCO) films were studied. The BLFCO (001) films (30 nm and 70 nm) were deposited on various single crystal substrates having lattice mismatch with the film in…
Heteroepitaxy of wurtzite semiconductors on corundum substrates is widely used in modern optoelectronic devices, because both crystals belong to the same hexagonal close-packed system. However, the constituent atoms in the wurtzite structure align in an ideal hexagon within the (0001) plane, whereas those in the corun…
Luminescent properties of the ytterbium doped zinc selenide crystals with various concentrations of the doping impurity in 0.03–8 at % range within the temperature interval from 6 K to 300 K were studied. It was shown that ytterbium does not form any proper photoluminescence (PL) bands in the visible spectral range, b…
Multilayers of Ge quantum dots (QDs, 3 nm in diameter) embedded in SiO2, separated by SiO2 barrier layer (3, 9, or 20 nm thick), have been synthesized by sputter deposition and characterized by transmission electron microscopy and light absorption spectroscopy. Quantum confinement affects the optical bandgap energy (1…
Strength and work hardening of TRIP matrix composite materials depend strongly on the testing temperature. Due to a temperature dependent driving force for the α′-martensite formation and a changing stacking fault energy in the metastable austenitic matrix, completely different deformation mechanisms can be observed a…
ABSTRACT This work aims at comparing the efficiency of three melt compounding methods for preparing polyamide 12 (PA12)/untreated clay composites. Conventional extrusion was compared with two water‐assisted extrusion methods previously described in the literature and respectively involving injection of water in the po…