Materials Literature
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Using a new analytic quantum mechanical method based on Slater's Xalpha method, we show that a fairly accurate estimate of the total energy of a molecule can be obtained from the exact energies of its constituent atoms. The mean absolute error in the total energies thus determined for the G2 set of 56 molecules is abo…
The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are compara…
We report the absorption cross-section of colloidal InAs quantum dots of mean radii from 1.6 to 3.45 nm. We find excellent agreement between the measured results and calculated values based on a model of small-particle light absorption. The absorption cross-section per dot is 6.2 x 10(-16)R(3) cm(2) at 2.76 eV and 3.1…
Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence (PL) spectroscopy. Resolution-limited peaks with an ultra-low spatial density originate in the recombination of excitons deeply bound to isolated nearest-neighbor isoelectronic Te pairs (Te2). This interpretation is confir…
Metamaterials--artificially structured materials with tailored electromagnetic response--can be designed to have properties difficult or impossible to achieve with traditional materials fabrication methods. Here we present a structured metamaterial, based on conducting split ring resonators (SRRs), which has an effect…
In Form gebracht: In einer Polyol-Synthese beeinflusst die Geschwindigkeit der Reduktion einer PtII-Vorstufe die Form von Pt0-Nanostrukturen. Diese kinetische Steuerung gelingt durch das Koppeln mit einer FeII/FeIII-Redoxreaktion und/oder das Blockieren autokatalytischer Zentren auf den Pt-Partikeln mit Sauerstoff. Di…
Getting into shape: The shape of Pt0 nanostructures obtained by polyol synthesis can be altered by controlling the rate of reduction of the PtII precursor. Kinetic control is achieved by coupling the reduction with an FeII/FeIII redox reaction and/or by blocking the self-catalytic sites of the Pt particles with oxygen…
We examined the catalytic effect of nanoparticle 3d-transition metals on hydrogen desorption (HD) properties of MgH(2) prepared by mechanical ball milling method. All the MgH(2) composites prepared by adding a small amount of nanoparticle Fe(nano), Co(nano), Ni(nano), and Cu(nano) metals and by ball milling for 2 h sh…
Gold colloidal nanoparticles (GNPs) were prepared by reducing a complex of Au+. Na3Au(SO3)2 with sodium citrate. The procedure provides control of the dimension of nanoparticles produced, which is a function of reaction time and concentration of reactants. The nanoparticles were separated by centrifugation and their c…
We have investigated the orbital and magnetic correlations of the manganese sub-lattice in the archetypical half-doped manganite La 0.5 Sr 1.5 MnO 4 using the enhanced sensitivity of resonant soft x-ray diffraction at the Mn L edges. We have separately measured the energy dependence of the scattered intensity from bot…
Heusler alloy Ni2MnIn thin films have been grown on InAs (001) by molecular beam epitaxy at growth temperatures ranging from 120 to 300 °C. For growth at 120 °C, transmission electron diffraction confirms the epitaxial growth of Ni2MnIn in the B2 crystal structure on InAs (001) with an epitaxial relationship of Ni2MnI…
Abstract The aim of this work is to investigate the intrinsic parameters that control the puncture resistance of materials used in protective clothing. The effect of various probe geometries and sample holder sizes on puncture tests results were investigated. Medical needles of different diameters and tip angles were…
Abstract CANDU Zr-2.5Nb pressure tubes are susceptible to a crack initiation mechanism known as Delayed Hydride Cracking (DHC), which is a process that involves hydrogen diffusion, hydride precipitation, hydride region formation, and fracture at a flaw tip. An overload occurs when the hydrided region is loaded to a st…
The title compound generates diffraction patterns which are indexable within the framework of the higher-dimensional description of incommensurate structures. However, it is difficult to discriminate the main reflections from the satellite ones. This paper has clarified that the structure can be treated as a strongly…
Two series of new ferroelectric liquid-crystalline diols with 1,3-propandiol group connected by a flexible spacer to the mesogenic part of the molecule have been synthesized. Both series are laterally substituted by methyl, methoxy, or chlorine substituents in the meta position to the carboxylic group of the 4-alkoxyb…
Abstract Sm‐doped bismuth titanate and random oriented Bi 4– x Sm x Ti 3 O 12 (BST) thin films were fabricated on Pt/Ti/SiO 2 /Si substrates using a pulsed laser deposition method. The structures and the ferroelectric properties of the films were investigated. Sm doping leads to a marked improvement in the remanent po…
The esterification of monoepoxy diluents (phenyl, cresyl, and butyl glycidyl ethers) and acrylic acid in presence of triphenylphosphine as catalyst was performed at 70 ○, 75 ○, 80 ○, 85 ○, and 90 ○C, and it followed first-order kinetics. The reactivity of aromatic monoepoxies was found to be higher than aliphatic, due…
This review describes the range of thermal analysis techniques that may be used to investigate the key thermal properties of formulations to be freeze-dried and the resultant products. The use of these allows development of cost-effective processing while maintaining optimum product quality.
We synthesized two diepoxy monomers containing a mesogenic group to investigate thermal conductivity of the resulting epoxy resins prepared by photo-polymerization of the monomers. One diepoxy monomer shows an enantiotropic nematic phase, whereas the other displayed enantiotropic smectic A and nematic phases. The epox…
Abstract Dielectric studies of poly(vinyl pyrrolidone)/ethyl alcohol (PVP–E) binary mixtures with concentration variations were carried out in the frequency range of 10 MHz to 10 GHz by time domain reflectometry at 15, 25, 35, and 45 °C. One relaxation process, corresponding to ethyl alcohol molecules in the poly(viny…