Materials Literature
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Spin transport properties of a spin-polarized two-dimensional electron gas are studied in the presence of electron-electron interactions. Longitudinal and transverse spin diffusion coefficients are calculated with the quantum transport equation which includes many-particle effects in the random phase approximation. We…
Results of our shell-model calculations concerning the determination of empirical parameters of inter-ionic potentials and the formation energies of point defects in LiNbO3 are presented. We employed the relaxed fitting method which is particularly appropriate for the modeling of low-symmetry structure. Attention is p…
Soil organic matter (SOM) is considered one of the most important components of soil quality (Larson and Pierce, 1991) and has long been recognized as a key component of terrestrial ecosystems. It is the primary source of energy for the flora and fauna found in the soil and an important source of inorganic nutrients f…
The Rothemund condensation reaction of pyrrole and aldehydes is an extensively used route to meso-tetraarylporphyrins, but simple modifications of the reaction conditions allow the formation of different macrocycles other than the expected porphyrin. In the presence of an excess of pyrrole, this modified Rothemund app…
Mono- and bifunctional oligo( p -phenylene vinylene)s (OPVs) functionalized with ureido- s -triazine units have been synthesized and fully characterized. In chloroform monofunctional OPV derivatives dimerize with a dimerization constant of K dim = (2.1 ± 0.3) × 10 4 L/mol, while bifunctional OPV derivatives are presen…
The aim of this work is to report on the luminescence properties of BaZnSiO 4 activated by Eu 3+ and Mn 2+ ions. Doped and undoped powder samples were prepared by solid-state reaction starting from oxides and carbonates or Ba 2 SiO 4:Eu 3+ and Zn 2 SiO 4:Mn 2+ precursors. X-ray diffraction powder data, IR vibrational,…
We present the results of a numerical investigation of the Ericksen-Leslie equations for the problem of electrohydrodynamic convection in a nematic liquid crystal. The combination of a finite element approach and numerical bifurcation techniques allows us to provide details of the basic flow and include the physically…
An inelastic x-ray scattering experiment has been performed in liquid aluminum for the purpose of studying the collective excitations at wave vectors below the first sharp diffraction peak. The high instrumental resolution (up to 1.5 meV) allows an accurate investigation of the dynamical processes in this liquid metal…
Measurements of acoustically driven cavitation luminescence indicate that this phenomenon is robust over a huge parameter space ranging from 10 kHz to >10 MHz. The minimum bubble radius achieved is an upper bound for the size of the light-emitting region and ranges from about 1 microm at 15 kHz to tens of nm at 11 MHz…
In a fluid out of equilibrium, the fluctuation-dissipation theorem (FDT) is usually violated. Using molecular dynamics simulations, we study in detail the relationship between correlation and response functions in a fluid driven into a stationary nonequilibrium state. Both the high temperature fluid state and the low…
Results of dc magnetization study are presented showing interesting thermomagnetic history effects across the antiferromagnetic to ferromagnetic transition in Ce(Fe$_{0.96}$Al$_{0.04})_2$. Specifically, we observe (i)ZFC/FC irreversibility rising with increasing field; (ii) virgin curve lying outside the envelope M-H…
Andreev reflection at the interface between a ferromagnet and a superconductor has become a foundation of a versatile new technique of measuring the spin polarization of magnetic materials. In this paper we will briefly outline a general theory of Andreev reflection for spin-polarized systems and arbitrary Fermi surfa…
We study the two-dimensional kinetic Ising model below its equilibrium critical temperature, subject to a square-wave oscillating external field. We focus on the multidroplet regime, where the metastable phase decays through nucleation and growth of many droplets of the stable phase. At a critical frequency, the syste…
We present calculations of the pressure tensor profile in the vicinity of the planar interface between isotropic liquid and nematic liquid crystal, using Onsager's density functional theory and computer simulation. When the liquid crystal director is aligned parallel to the interface, the situation of lowest free ener…
The ``classical'' model of the ${[\mathrm{AlO}}_{4}{]}^{0}$ defect center in irradiated quartz, an Al impurity having replaced a four-coordinated Si atom, is that a hole forms in a nonbonding orbital of an oxygen atom, with consequent asymmetric relaxation along that particular Al-O direction. This model has been prop…
Broad-band dielectric spectroscopy (10 -1 −10 7 Hz) has been used to study the molecular dynamics in a set of bisphenol A poly(ester carbonate)s (BPA-PECs) and tetramethylbisphenol A poly(ester carbonate)s (TMBPA-PECs) containing 1,4-cyclohexylene dicarboxylate (CHDC) linkages. Four dielectric relaxation processes are…
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ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of Macroporous Polymer Beads by Suspension Polymerization Using Supercritical Carbon Dioxide as a Pressure-Adjustable PorogenColin D. Wood and Andrew I. CooperView Author Information Donnan and Robert Robinson Laboratories…
Unambiguous observation of the reorientation of azobenzene chromophores toward the propagation direction of the actinic light has been performed. Prolonged irradiation of a spin-coated film of liquid crystalline poly[6-{4-(4‘-methoxyphenyl)azophenyloxy}hexyl methacrylate] ( C6MeO ) with 436 nm light for n−π* excitatio…
A switchable diffuse reflective film with high color purity is demonstrated using holographic-polymer dispersed liquid crystals (HPDLC). By recording a diffuse hologram directly into the LC/polymer film, the diffuse mode HPDLC exhibit viewing angles an order of magnitude larger than the conventional mode. A simple phe…