Materials Literature
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The preparative flexibility of hydrothermal syntheses needs to be systemised for exploring complex structure-synthesis relationships and morphology control options in materials chemistry. This is demonstrated for the targeted hydrothermal preparation of molybdenum oxide materials: firstly, in situ studies were employe…
In this work, relationships between chemical and physical properties of fluorine doped tin oxide films prepared by the chemical spray pyrolysis technique have been studied. Changes in the structural, optical and electrical properties of these films in relation to their doping concentrations determined by the resonant…
We show that electropolishing of tantalum metal in a single step of about 5 min can reproducibly lead to dimples tens of nanometers in diameter, regular in shape, monodispersed in size, and arranged in highly ordered arrays which even transverse grain boundaries. Dimpled tantalum is ductile, high melting, and chemical…
Conjugated polymers are excellent barriers for membrane separations because their porosity can be controlled at the molecular level through chemical doping. Polyaniline (PANI) is particularly attractive because simple acid/base doping/undoping enables a controllable level of doping that can be readily achieved using d…
The different reactions between edge or screw dislocations and interstitial Frank loops were studied by means of molecular dynamics simulations. The calculations were performed at 600 K using an embedded atom method (EAM) potential describing a model FCC material with a low stacking fault energy. An interaction matrix…
A Comment on the Letter by Hoonkyung Lee, Woon Ih Choi, and Jisoon Ihm, Phys. Rev. Lett. 97, 056104 (2006).Received 2 October 2006DOI:https://doi.org/10.1103/PhysRevLett.97.209601©2006 American Physical Society
We utilize NMR field cycling relaxometry to study the crossover from glassy dynamics (t approximately > tau alpha) through Rouse to reptation behavior in a series of monodisperse polybutadienes with molecular weights M=355 to 817,000 g/mol. We separate characteristic polymer dynamics from the total spectrum dominated…
Sets of lattice parameter data have been obtained from high resolution neutron and synchrotron x-ray powder diffraction patterns collected in situ as a function of temperature for perovskites in the (Ca,Sr)TiO 3 solid solution. An updated phase diagram is proposed in which there is a stability field for the I 4/ mcm s…
We report on an observation of a fast 1.5 microm photoluminescence band from Er3+ ions embedded in an SiO2 matrix doped with Si nanocrystals, which appears and decays within the first microsecond after the laser excitation pulse. We argue that the fast excitation and quenching are facilitated by Auger processes relate…
Room temperature hydrophilic ionic liquids, 1-methyl-3-ethylimidazolium salts containing ethyl-sulfate anions, have dramatic effects on the morphology changes of electrochemically grown Cu 2 O crystals at room temperature in aqueous solutions. The shape of Cu 2 O crystals evolves from cubic to octahedral and spherical…
The solution behavior of the largest inorganic acid known thus far, the neutral, spherical iron/molybdenum/oxide nanocluster {Mo72Fe30} ([triple bond{(MoVI) MoVI5}12FeIII30 1a), including the pH-controlled deprotonation, is reported. The acidic properties are due to the 30 peripheral, weakly acidic FeIII(H2O) groups t…
Using the WIEN2k band-structure program in the generalized gradient approximation (GGA) and a procedure based on minimization of the Gibbs free energy at 0 K, we calculate the lattice parameters of face-centred-cubic (fcc) and of hexagonal-close-packed (hcp) aluminium in the pressure range from 1.8 to 3.3 Mbar. The re…
Absorption cross-sections and corresponding molar extinction coefficients of solution-based CdSe and CdTe nanowires (NWs) are determined. Chemically grown semiconductor NWs are made via a recently developed solution-liquid-solid (SLS) synthesis, employing low melting Au/Bi bimetallic nanoparticle "catalysts" to induce…
We have investigated the magnetoresistance of ferromagnet-semiconductor devices in an InAs two-dimensional electron gas system in which the magnetic field has a sinusoidal profile. The magnetoresistance of our device is large. The longitudinal resistance has an additional contribution which is odd in applied magnetic…
We explore and compare three approximate schemes allowing simple implementation of complex density functionals by making use of selfconsistent implementation of simpler functionals: (i) post-LDA evaluation of complex functionals at the LDA densities (or those of other simple functionals); (ii) application of a global…
TmAgGe is an antiferromagnet in which the spins are confined to distorted kagome-like planes at low temperatures. We report angle-dependent measurements of the magnetization $M$ in fields of up to 55 T that show that there are two distinct and separate energy scales present in TmAgGe, each responsible for a set of ste…
First-principles calculations have been conducted to study the structural, vibrational, and dielectric properties of $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Si}}_{3}{\mathrm{N}}_{4}$. Calculations of the zone-center optical-mode frequencies (including longitudinal-optical/transverse-optical splittings), Born…
Ag-doped ZnO films were prepared by direct current reactive magnetron sputtering using a zinc target with various Ag-chips attached. The influence of Ag doping on the microstructure, photoluminescence and Raman scattering of ZnO films were systematically investigated. The results indicate that ZnO films doped with Ag…
We present an effective mass theory for SiGe/Si/SiGe quantum wells, with an emphasis on calculating the valley splitting. The theory introduces a valley coupling parameter, $v_v$, which encapsulates the physics of the quantum well interface. The new effective mass parameter is computed by means of a tight binding theo…
Syntheses, structures, and magnetic properties of one mononuclear inclusion compound [CuIIL1 within (H2O)] (1) and three tetrametal systems of the composition [{CuIIL1}2{CuIIL1MII(H2O)3}]ClO4)2 (M = Cu (2), M = Co (3), M = Mn (4)) derived from the hexadentate Schiff base compartmental ligand N,N'-ethylenebis(3-ethoxys…