Materials Literature
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Within the framework of a two-band tight-binding model, we have performed calculations of giant magnetoresistance, exchange coupling and thermoelectric power (TEP) for a system consisting of three magnetic layers separated by two non-magnetic spacers with the first two magnetic layers strongly antiferromagnetically ex…
Several samples of poly(ethylene terephthalate- co -2,6-naphthalene dicarboxylate) were synthesized with different contents of dimethyl-2,6-naphthalene dicarboxylate (DMN). The polymer samples were ground into powders, and steady-state and time-resolved fluorescence measurements were carried out on these copolymers. T…
Different thermodynamics in phenolic blends with different polymeric modifiers, i.e., phenoxy, poly(decamethylene adipate), poly(ethylene oxide), and poly(vinyl alcohol), calculated by the Painter and Coleman association model (PCAM) are examined. The thermodynamics is calculated based upon the equilibrium constants d…
Atomic force microscopic image on mica substrate, which was dipped for 10 min in an aqueous solution of fifth-generation poly(amido amine) dendrimer with hydroxyl end groups, displayed a flatter texture of dendrimer-adsorbed surface. On the external contrast variation of small-angle neutron scattering for aqueous dend…
A new experimental set-up controlled by computer has been made to measure the pyroelectric charge of ferroelectric materials with a relatively high conductivity at slow rates of temperature variation. It allowed us to obtain the polarisation vs. temperature behaviour of PZT with various compositions in the whole range…
We report the synthesis and room temperature crystal structures of the heretofore unknown, metastable manganites La2-2xSr1+2xMn2O7+delta (0.5 < x < 0.9) via high-temperature (T=1650 C) quenching followed by low-temperature (T=400 C) annealing to fill oxygen vacancies; this approach enables access to the electronic, ma…
Dynamic plastic response of a submarine oil pipeline to an underwater explosion bubble is studied in this paper. A detailed fluid-structure analysis is given to find the fluid forces acting on the pipeline. Assuming the pipeline is made from rigid, perfectly plastic material, we obtain the hydroplastic equation govern…
We revealed the existence of epitaxial α-Fe2O3 grains in Ba-ferrite thin films on sapphire (001) using synchrotron x-ray scattering. The antiferromagnetic α-Fe2O3 grains were formed during the crystallization of amorphous Ba-ferrite films grown on sapphire (001) by radio frequency sputtering deposition. The crystal do…
We report solution-state pulsed field gradient nmr studies of a native sequence-derived 23-residue peptidomimetic, N alpha-acetyl-QPGVGGRQPGMGGQPGVGGRQPG-C alpha-amid, that incorporates the prevalent GVGGR and GMGGQ repeats found in the sea urchin embryo intracrystalline spicule matrix protein, SM50 (Strongylocentrotu…
Using optical birefringence, small-angle neutron scattering, and field-theoretic methods, we study the effects of frustrating quenched randomness and connectivity on microphase ordering in copolymer melts. Our results show that randomly grafted copolymers are good model systems to examine these effects, and we find th…
We have observed dynamical diffraction in the $[[\left(0240\overline{2}4\right)$ and $[[\left(0460\overline{4}6\right)$ reflections of the icosahedral quasicrystal AlPdMn in the back-reflection geometry ( ${\ensuremath{\theta}}_{B}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}90\ifmmode^\circ\else\textdegree\fi{}…
We argue that the new distinct features observed in doped ferromagnetic manganites ${R}_{1\ensuremath{-}x}{D}_{x}{\mathrm{MnO}}_{3}$ ( $RD\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\mathrm{LaSr}$, PrSr, NdSr, and LaCa), the softening of the spin-wave dispersion at the zone boundary and the increase of the spin…
The effects of racemization of aspartic acid on triple-helical formation have been studied using a "host-guest" peptide approach where selected guest Gly-Xaa-Yaa triplets were included within a common acetyl-(Gly-Pro-Hyp)3-Gly-Xaa-Yaa-(Gly-Pro-Hyp)4-Gly-Gly-amide frame-work. Four guest triplets, Gly-Asp-Hyp and Gly-As…
The interface between tetragonal Nd2Fe14B phase and Nd-rich grain boundary phase in Nd–Fe–B sintered magnets was investigated with high resolution transmission electron microscope. Selected area diffraction patterns of the Nd-rich phase can be indexed by face-centered-cubic (fcc) structure with the lattice constant of…
We use a combination of single nanoparticle luminescence and scanning force microscopy to determine the quantum efficiency (QE) of single porous Si nanoparticles and to determine the ratio of luminescent nanoparticles deposited on a silica surface to the total nanoparticles. An estimate of the QE of bulk porous Si bas…
We calculate perturbatively the tunneling decay rate $Γ$ of the metastable phase in the quantum d=1 Ising model in a skew magnetic field near the coexistence line $0
We have measured the velocity of a running crack in brittle single crystal silicon as a function of energy flow to the crack tip. The experiments are designed to permit direct comparison with molecular dynamics simulations; therefore the experiments provide an indirect but sensitive test of interatomic potentials. Per…
Large twist-angle grain boundaries in layered structures are often described by Scherk's first surface, whereas small twist-angle grain boundaries are usually described in terms of an array of screw dislocations. We show that there is no essential distinction between these two descriptions and that, in particular, the…
We briefly introduce hysteresis in spatially extended systems and the dynamic phase transition observed as the frequency of the oscillating field increases beyond a critical value. Hysteresis and the decay of metastable phases are closely related phenomena, and a dynamic phase transition can occur only for field ampli…
A previously unreported ferroelectric phase has been discovered in a highly homogeneous sample of PbZr0.52Ti0.48O3 by high-resolution synchrotron x-ray powder diffraction measurements. At ambient temperature the sample has tetragonal symmetry (at=4.037 Å, ct=4.138 Å), and transforms below ∼250 K into a phase which, un…