Materials Literature
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The effect of Fe doping (20%) on the Mn site in the ferromagnetic ($x=0.37$) and the antiferromagnetic ($x=0.53$) phases of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ has been studied. The same ionic radii of ${\mathrm{Fe}}^{3+}$ and ${\mathrm{Mn}}^{3+}$ cause no structure change in…
A study was conducted on the effects of microstructure, atmosphere, and several dopants on the electrical conductivity of bismuth titanate (Bi 4 Ti 3 O 12 , BIT). Increased grain size increased the conductivity in undoped BIT as did acceptor dopants that substituted for either Bi (Ca and Sr) or Ti (Fe). A donor dopant…
We present a molecular-dynamics study of the self-dynamics of water molecules in deeply supercooled liquid states. We find that the decay of single-particle dynamics correlation functions is characterized by a fast initial relaxation toward a plateau and by a region of self-similar dynamics, followed at late times by…
Electron configurations close to the tetrahedral hybridization are found in pure amorphous carbon at a concentration which depends on preparation conditions. Tetrahedral bonding at levels of approximately 80% is found in amorphous carbons formed from beams of carbon ions with energies in a `window' between 20 eV and a…
Article Determination of hemicelluloses and pectins in wood and pulp fibres by acid methanolysis and gas chromatography was published on December 1, 1996 in the journal Nordic Pulp & Paper Research Journal (volume 11, issue 4).
Other| December 01, 1996 Thermodynamics of order-disorder in minerals; II, Symmetric formalism applied to solid solutions Tim Holland; Tim Holland University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom Search for other works by this author on: GSW Google Scholar Roger Powell Roger Powell Univ…
One of the ultimate objectives for sintering studies is to be able to predict densiflcation results under different thermal histories for a given processing method. It has been reported that the geometric parameters related to sintering often are functions only of density for a given powder and green‐body process, pro…
Novel liquid-crystal devices are described that generate linearly polarized light with axial symmetry; the beam propagation axis is the symmetry axis. Such light fields can be characterized by a polarization order number P. For example, P = 1 fields represent radially or azimuthally polarized light. The reorientation…
Abstract We consider the rheological behaviour of felsic magma in the zone of partial melting and during subsequent crystallization. We also introduce and combine concepts (mushy zone, percolation theory, granular flow, shear localization) derived from the non-geological literature and apply them to field observations…
The role of grain boundaries in the magnetoresistance (MR) properties of the manganites has been investigated by comparing the properties of epitaxial and polycrystalline films of ${\mathrm{La}}_{0.67}{D}_{0.33}\mathrm{Mn}{\mathrm{O}}_{3\ensuremath{-}\ensuremath{\delta}} (D=\mathrm{C}\mathrm{a},\phantom{\rule{0ex}{0ex…
Unlike Y123 which forms only a stoichiometric compound, the light rare earth elements (LREs: La, Nd, Sm, Eu, Gd) form a solid solution . The presence of such solid solution caused a depression in the superconducting transition temperatures , particularly for La123, Nd123 and Sm123 when they are melt processed in air.…
Abstract The palygorskite-sepiolite group of clay minerals has a wide range of industrial applications derived mainly from its sorptive, rheological and catalytic properties which are based on the fabric, surface area, porosity, crystal morphology, structure and composition of these minerals. For assessing potential i…
Using molecular-dynamics computer simulations we investigate how in silica the glass transition and the properties of the resulting glass depend on the cooling rate with which the sample is cooled. By coupling the system to a heat bath with temperature ${\mathit{T}}_{\mathit{b}}$(t), we cool the system linearly in tim…
Large disorder effects due to size differences between $A$-site ${R}^{3+}$ ($R=\mathrm{L}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{N}\mathrm{d},\phantom{\rule{0ex}{0ex}}\mathrm{S}\mathrm{m}$) and ${M}^{2+} (M=\mathrm{C}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{S}\mathr…
The kninetics of acid-catalyzed acetalization and ketalization of poly(vinyl alcohol) (PVA) were systematically studied in completely homogeneous media with carefully selected solvents. Thus the acetalization reaction was run in water with six aldehydes [R1CHO (R1 = H, CH3, C2H5, n-C3H7, i-C3H7, ClCH2)], whereas the k…
Different synthetic methods for the preparation of polyfunctional fluorinated oligomers were explored and the results compared. Fluoropolyether macromonomers bearing epoxy, allyl, and polyhydroxy end groups were synthesized and spectroscopically characterized. For obtaining a polyol (namely tetraol) functionality, a h…
The thermal decomposition behavior of the aged tetrahydrofuran copolymers with 3-azidomethyl-3′-methyloxetane (AMMO) or 3-nitratomethyl-3′-methyloxetane (NMMO) were studied by thermogravimetry and evolved gas analysis, and compared with aged polytetrahydrofuran (poly-THF) The thermal stability decreased in the order p…
Water sorption and transport properties for a series of polysulfones are presented and interpreted in terms of the changes in the structure of the repeat unit compared to that of bisphenol A polysulfone. The differences between the sorption and diffusion of water and of permanent gases in these materials are also disc…
A new technique based on light depolarizing microscopy was developed for studying non-isothermal crystallization of polymers at average cooling rates up to about 5000°C/min. The polymer is cooled down by a gaseous cooling medium supplied at a constant temperature. The temperature of polymer is measured by a thermocoup…
It is shown that the current-perpendicular-to-plane giant magneto-resistance (CPP-GMR) oscillations, in the ballistic regime, are strongly correlated with those of the exchange coupling (J). Both the GMR and J are treated on equal footing within a rigorously solvable tight-binding single-band model. The strong correla…