Materials Literature
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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…
The effects of physical aging, degree of crystallinity, and orientation of poly(lactic acid) (PLA) were studied using differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). The samples of PLA with 96% [L] and 4% [D] contents were prepared by injection molding. The physical aging of PLA strongl…
Transition metal sulfur (TMS) sites in biology comprise mononuclear, and homo- and heteropolynuclear centers in metalloproteins. In industry, the use of TMS systems in lubrication and in hydrotreating catalysis is of great technological significance. Trends in the structure and reactivity of molecular TMS systems incl…
Transition metal sulfur (TMS) sites in biology comprise mononuclear, and homo- and heteropolynuclear centers in metalloproteins. In industry, the use of TMS systems in lubrication and in hydrotreating catalysis is of great technological significance. Trends in the structure and reactivity of molecular TMS systems incl…
Using the plane wave pseudopotential method we performed density functional theory calculations on the stability of steps and self-diffusion processes on Ag(100). Our calculated step formation energies show that the {111}-faceted step is more stable than the {110}-faceted step. In accordance with experimental observat…
The formation of dislocation-free three-dimensional islands during the heteroepitaxial growth of lattice-mismatched materials has been observed experimentally for several material systems. The equilibrium shape of the islands is governed by the competition between the surface energy and the elastic relaxation energy o…
Schiff bases of hydroxy benzaldehydes with aliphatic and aromatic 1,2-diamines were re-sinified in HCHO in alkaline media. These resins were found to form complexes readily with Cu(II), Co(II), and Ni(II). The materials were characterized by infrared, 1H-NMR, UV-visible (UV-vis) spectral studies, and thermogravimetric…
A series of eight thermoplastic polyurethane elastomers were synthesized from 4,4′-methylene diphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender, with poly(hexamethylene oxide) (PHMO) macrodiol soft segments. The soft segment molecular weights employed ranged from 433 g/mol to 1180 g/mol. All materials…
We utilize the many-body potentials developed by Sutton and Chen(1990) within the context of the tight-binding approach to study the bulk properties of metals and metal alloys in molecular dynamics (MD) simulations. In the simulations of Pt-Rh alloys we used the MD algorithms based on an extended Hamiltonian formalism…