Materials Literature
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A new series of transition-metal oxyhalides (MCl)LaNb(2)O(7) (M = Cr, Mn, Fe, Co) have been prepared by a simple topochemical route. Layered perovskite hosts (ALaNb(2)O(7), A = Li, Na, K or Rb) were reacted with the corresponding anhydrous metal halides under mild reaction conditions (<400 degrees C). The compounds we…
Abstract Nineteen kinds of minerals, alone and in bicomponent mixtures with LaC (a mixed ternary complex of trivalent lanthanum stearate and stearin), were added to isotactic polypropylene (iPP). The influences of the minerals on the crystallographic forms of iPP were investigated. A wide‐angle X‐ray diffraction exami…
The high frequency collective dynamics of liquid hydrogen fluoride is studied by inelastic x-ray scattering on the coexistence curve at T = 239 K. The comparison with existing molecular dynamics simulations shows the existence of two active relaxation processes with characteristic time scales in the subpicosecond rang…
Abstract By mixing natural rubber latex uniformly with methyl methacrylate‐grafted natural rubber latex and then carrying out prevulcanization, we obtained blends with stable viscosities. Under certain blending ratios, the blends maintained good basic properties, and the heat stability time ( T HS ) of the blend incre…
meso -Tetraphenyl-21-chalcogenaporphyrins 4 − 6 (S, Se, and Te as 21-chalcogen atoms, respectively) and meso -tetraphenyl-21,23-dichalcogenaporphyrins 7 − 10 [(S,S), (Se,S), (Se,Se), and (Te,S) combinations as 21,23-chalcogen atoms, respectively] were prepared by condensation of the appropriate 2,5-bis(phenylhydroxyme…
The importance of vicinal and long-range interresidue effects in determining the stability of the collagen triple helix has been investigated by quantum mechanical (QM) and molecular mechanical (MM) computations on suitable model polypeptides, taking into account solvent effects by the polarizable continuum model (PCM…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSurface and Precipitation Polymerization of AnilineSvetlana Fedorova and Jaroslav StejskalView Author Information Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, Russia Institute of Macromolecular Chemistry, Academy of Sciences of the…
A series of experiments has been designed and conducted to test a recent model for the morphological behavior of polymer−layered silicate (PLS) nanocomposites, where a PLS nanocomposite is composed of a homopolymer matrix, a layered silicate clay mineral filler, and an organic surfactant modifier. For nearly complete…
To explore the ability of the “effective concentration” model to quantitatively predict the individual local dynamics of each component in miscible polymer blends, three model systems [polystyrene/poly(vinyl methyl ether), polystyrene/poly( o -chlorostyrene), and poly(vinyl methyl ether)/poly( o -chlorostyrene)] are s…
Abstract The hot‐wire parallel technique standardized for determining the thermal conductivity of ceramic materials was employed in the determination of the thermal properties of polymers. For these materials, additional care must be taken considering the low melting point of polymers, when compared with that for cera…
Various 109Ag NMR techniques are used to study silver diffusion in silver iodide/silver phosphate glasses. In particular, for the first time, four-dimensional (4D) NMR is applied on solid ion conductors. All experiments consistently show that silver dynamics are governed by a very broad, continuous distribution of cor…
Abstract A suspension of non‐neutrally buoyant, large, nearly monodisperse spheres is studied both in batch sedimentation and in shear between concentric rotating cylinders. We apply a continuum constitutive equation based on the diffusive flux model augmented with buoyancy terms derived by Acrivos and coworkers and d…
The efficacy of a sonophotochemical reactor coupling ultrasonic irradiation with photocatalytic oxidation has been evaluated using formic acid degradation as the model reaction. The reactor used in the present work is a hexagonal flow cell irradiated with multiple-frequency transducers placed at the wall of the reacto…
We report the photophysical characterization of the two tautomers ( 1e and 1i ) of 5,10,15,20-tetraphenyl N-confused free-base porphyrin, potential building blocks in assemblies designed for artificial photosynthesis, using a combination of steady state and time-resolved techniques. Tautomer 1e was found to have a sig…
The 3,5-di-tert-butyl-catecholato and 9,10-phenanthrenecatecholato adducts of the cobalt-tetraazamacrocycle complex Co(Me(4)cyclam)(2+) (Me(4)cyclam = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) were synthesized and oxidized. The oxidation reaction products were isolated in the solid state as hexafluoropho…
The inferred crystallographic class of circumstellar silicon carbide based on astronomical infrared spectra is controversial. We have directly determined the polytype distribution of circumstellar SiC from transmission electron microscopy of presolar silicon carbide from the Murchison carbonaceous meteorite. Only two…
Microfibrous self-aggregation of chromophoric groups of porphyrin and/or pyrene substituted by didodecyl l -glutamic acid in organic media is confirmed by transmission electron microscopic (TEM) observation. Chromophoric probes of porphyrin and pyrene moieties enable evaluation of their assembling behavior photophysic…
Low-field and high-field transport properties of carbon nanotubes/polymer composites are investigated for different tube fractions. Above the percolation threshold ${f}_{c}\ensuremath{\sim}0.33%,$ transport is due to hopping of localized charge carriers with a localization length $\ensuremath{\xi}\ensuremath{\sim}10\e…
Several unexpected and intriguing magnetic phenomena have been observed in the ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$ compound. First, below \ensuremath{\sim}130 K, ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$ is antiferromagnetic in a zero magnetic field, but it can be transformed into the ferromagnetic state both irreversibly…
Two series of novel fully conjugated oligomers, oligothiophene-functionalized 9,9'-spirobifluorene derivatives, have been developed in this contribution. First, four 9,9'-spirobifluorene bromide derivatives (compounds 1a-d) are prepared through various synthetic routes. Oligothiophene derivatives with or without subst…