Materials Literature
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A new disk-shaped amphiphilic dendrimer has been synthesized by attaching sixty-four 12-hydroxydodecanoic acid chains to a fourth generation poly(amido amine) (PAMAM) dendrimer core. Surface pressure and surface potential−area isotherm measurements have shown that the dendrimer forms a stable monolayer at the air/wate…
In this paper we present embedded-cluster calculations on singly charged and neutral oxygen vacancies (or F centres) in the oxide perovskite BaTiO 3 . The simulations include Hartree-Fock theory with MP2 corrections and density-functional-theory calculations for a central quantum defect cluster and a pair-potential de…
The synthesis of new ferrocene derivatives bearing phenoxy and/or formyl groups allows one to obtain phosphorus-containing dendrimers with ferrocene units at the core, within the branches, and at the periphery. Dendrimers with a ferrocene at the core were built from 1,1‘-ferrocenedicarboxaldehyde up to the fourth gene…
The metathesis reaction of K 4 Ge 4 Se 10 with various alkyl tri- and dimethylammonium halides [C n H 2 n +1 N(CH 3 ) 3 - m H m ]X ( n = 8, 9, 10, 12, 14, 16, 18; m = 0, 1; X = Cl, Br) led to several new surfactant−inorganic template phases containing selenogermanate adamantane units [Ge 4 Se 10 ]. 4 - The crystal str…
A technique for using rheological information to determine the level of long chain branching in polyethylenes produced using a constrained geometry catalyst and having low levels of branching is described. The complex viscosity as a function of frequency is used, along with a molecular weight distribution (MWD) determ…
On the basis of data from a combination of X-ray diffraction techniques, the B O morph of hexatriacontane [H(CH 2 ) 36 H], a low-molecular-mass gelator of several classes of liquids (including shorter n -alkanes), has been identified unambiguously as the molecular packing arrangement within the microplatelet units of…
Room temperature x-ray diffraction, magnetization and neutron diffraction measurements up to 500 K have been carried out on polycrystalline bulk double perovskites AA'FeMoO 6 (AA' = Ba 2 , BaSr, Sr 2 , Ca 2 ) in order to determine and correlate their structural and magnetic properties. As the average ionic radius is d…
Organometallic- and organic-based materials exhibiting the technologically important property of bulk magnetism have been designed, prepared, and studied. These magnets are prepared via conventional organic chemistry methodologies and unlike conventional inorganic-based magnets do not require metallurgical processing.…
The symmetry implantation in the tight-binding method is analysed. A transparent algorithm is proposed to calculate eigenvalues and eigenvectors with automatic assignation by the complete set of conserved quantum numbers. For crystals, the energy bands are obtained with no summation over the lattice, while the eigenve…
Developments of single crystal ED patterns in melt-crystallized poly(trimethylene terephthalate) (PTT) have been successfully achieved. Five different zonal electron diffraction patterns containing a total of 14 independent reflections were obtained. The PTT structure under strain-free conditions was identified as a t…
Boron arsenide, the typically-ignored member of the III-V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its Gamma conduction band minimum is p-like (Gamma_15), not s-like (Gamma_1c), it has an X_1c-like indirect band gap, and its bond charge is distributed almost equally on the two at…
Pr 0.5 Ca 0.5 Mn 0.99 Cr 0.01 O 3 shows several anomalous properties: Field-cooled (FC) resistivity at 10 K is several orders of magnitude lower than the zero-field cooled (ZFC) value, magnetoresistance isotherm at 125 K is asymmetric about the origin (H=0 T) and resistivity and magnetization are hysteretic between fi…
The giant intrinsic hysteresis as a function of hydrogen concentration $x$ in the optical and electrical properties of the archetypal switchable mirror ${\mathrm{YH}}_{x}$ is eliminated by alloying Y with the chemically similar La. The ${\mathrm{La}}_{1\ensuremath{-}z}{\mathrm{Y}}_{z}{\mathrm{H}}_{x}$ films with $z\en…
The microstructure of polycrystalline ZnO thin films grown on amorphous fused quartz has been studied by transmission electron microscopy and electron energy loss spectroscopy (EELS). The optical functions of the grain and grain boundary of ZnO acquired from EELS are compared to elucidate the mechanism of the formatio…
Thickness dependence of the soft mode E(1TO) of tetraganol lead titanate thin film, deposited on Pt-coated Si by a chemical solution deposition, was determined with Raman scattering measurements. A downshift of the soft mode was attributed to the residual stress in the thin film, which was estimated in the range of 1.…
The various components in the N 1s photoemission spectra of amorphous carbon nitride are identified by measuring their photon energy dependence and comparing the experimental results with ab initio multiple scattering calculations. The intensity modulations with photon energy are due to the extended x-ray absorption f…
Carbon nitride films were deposited using a low pressure, dual ion beam system consisting of a filtered cathodic vacuum arc and a plasma beam source for carbon and nitrogen ions, respectively. This system maintains highly ionized beams even at high nitrogen fluxes, unlike in single beam systems. Film composition and b…
In a power transformer, high levels of partial discharge activity may lead to an insulation failure. If a partial discharge (PD) could be detected and located before the insulation fails, the transformer could be repaired or replaced before any consumers connected to the transformer lose supply. A technique is describ…
The dynamics of two fragile glass forming liquids was studied as a function of temperature and pressure using dynamic light scattering. On the basis of measured data we evaluated the pressure and temperature scaling of the alpha relaxation. All the isotherms can be superimposed and form a master curve when the reduced…
Ta 2 O 5 films deposited on Si substrates were investigated using transmission Fourier-transform infrared spectroscopy. We found a new absorption peak at 2340 cm−1 that can be characterized as a stretching vibration mode due to Ta=O bonds in the films. This peak appeared following annealing in O2 ambient, but not in N…