Materials Literature
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The Airy gas model of the edge electron gas is used to construct an exchange-energy functional which is an alternative to those obtained in the local density and generalized gradient approximations. Test calculations for rare gas atoms, molecules, solids and surfaces show that the Airy gas functional performs better t…
Dielectric nonlinear response of (PbMg$_{1/3}$Nb$_{2/3}$O$_3$)$_{0.9}$(PbTiO$_3$)$_{0.1}$ (0.9PMN-0.1PT) relaxor ceramics was investigated under different ac drive voltages. It was observed that: (i) the dielectric permittivity is independent on ac field amplitude at high temperatures; (ii) with increasing ac drive, t…
The basic Landau model for uniaxial systems of the II class is nonintegrable, and allows for various stable and metastable periodic configurations, beside that representing the uniform (or dimerized) ordering. In the present paper we complete the analysis of this model by performing the second order variational proced…
The persistent decay of bubble clusters in coarsening two-dimensional soap froths is measured experimentally as a function of cluster volume fraction. Dramatically stronger decay is observed in comparison to soap froth models and to measurements and calculations of persistence in other systems. The fraction of individ…
We investigate the question of stability of a solid thin film which experiences external interactions such as van der Waals forces from a contacting surface or forces from an external electric field. Both perfectly elastic and viscoelastic material behaviours are considered in linear stability analysis performed here.…
We present a self-consistent electronic structure calculation method based on the {\it Exact Muffin-Tin Orbitals} (EMTO) Theory developed by O. K. Andersen, O. Jepsen and G. Krier (in {\it Lectures on Methods of Electronic Structure Calculations}, Ed. by V. Kumar, O.K. Andersen, A. Mookerjee, Word Scientific, 1994 pp.…
We present a more detailed account of our recently reported [Hass, K. C.; Schneider, W. F.; Curioni, A.; Andreoni, W. Science 1998, 282, 265] first-principles molecular dynamics investigation of the static and dynamical behavior of adsorbed H 2 O on α-Al 2 O 3 (0001). Al-terminated surfaces with varying degrees of H 2…
Deciphering the mechanism(s) of β-sheet mediated self-assembly is essential for understanding amyloid fibril formation and for the fabrication of polypeptide materials. Herein, we report a simple peptidomimetic that self-assembles into polymorphic β-sheet quaternary structures including protofilaments, filaments, fibr…
The coalescence of single-walled nanotubes is studied in situ under electron irradiation at high temperature in a transmission electron microscope. The merging process is investigated at the atomic level, using tight-binding molecular dynamics and Monte Carlo simulations. Vacancies induce coalescence via a zipper-like…
Hydrophilic polyurethanes have the unique property of being able to absorb or otherwise manage moisture-and this makes them valuable in medical and a number of other important commercial applications.This new book provides a concise, unified presentation of hydrophilic polyurethanes technology and applications. All im…
The stereochemical course of reduction of dienoyl-coenzyme A (CoA) thiolesters catalyzed by the 2,4-dienoyl-CoA reductase from rat liver mitochondria was investigated. The configuration of the double bond in the 3-enoyl-CoA products was determined by (1)H NMR, and experiments to determine the stereochemical course of…
The general synthetic methods presented in this paper make available, on a preparative scale, unprecedented porphyrinogen-derived skeletons, including their functionalization at the meso positions. The stepwise dealkylation of meso- octaalkylporphyrinogen R 8 N 4 H 4 [R = Et, 1; R = Bu n, 2 ] was chemically, mechanist…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSurface-Enhanced Raman Scattering Spectroscopy of Single Carbon Domains on Individual Ag Nanoparticles on a 25 ms Time ScalePatrick J. Moyer, Jan Schmidt, Lukas M. Eng, Alfred J. Meixner, Gunther W. Sandmann, Hartmut Dietz, and Waldfried PliethView Author Information I…
Carbon-supported Wacker-type catalysts that showed high activities in CO oxidation at low temperatures were characterized with X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) techniques in order to correlate the catalytic activity with the structures and electronic states of Pd and Cu. The active st…
The syntheses of the parent compounds [(p-Bu(t)-calix[4]-(O)2(OR)2)Fe-L] [R = Me, L = THF, 5; R = Bu(n), L = THF, 6; R = PhCH2, L = THF, 7; R = SiMe3, L = none, 8] have been performed by reacting the protonated form of the dialkylcalix[4]arene with [Fe2Mes4] [Mes = 2,4,6-Me3C6H2]. All of them undergo one-electron oxid…
A new class of amphiphilic linear−dendritic diblock copolymers based on hydrophilic linear PEO and hydrophobic dendritic carbosilane were synthesized using a divergent approach at the allyl end group of the allyl-terminated PEO. The amphiphilic nature of these block copolymers was highly dependent on the size of the h…
[reaction: see text] Diverse Lewis acids and Bronsted acids were examined in the two-step, one-flask synthesis of meso-tetraphenylporphyrin, N-confused tetraphenylporphyrin, and tetraphenylsapphyrin. The scope of acid catalysis was found to be very broad, with 35 of 45 acids providing TPP in yields ranging from 5% to…
ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTSurface Analysis: X-ray Photoelectron Spectroscopy and Auger Electron SpectroscopyNoel H. Turner and John A. SchreifelsView Author Information Department of Chemistry, George Washington University, Washington, D.C. 20052 Department of Chemistry, George Mason University, Fairf…
Quantum Monte Carlo simulations of interacting electrons in solids often use Slater-Jastrow trial wave functions with Jastrow factors containing one- and two-body terms. In uniform systems the long-range behavior of the two-body term may be deduced from the random-phase approximation (RPA) of Bohm and Pines. Here we g…
White light tunable phosphors are obtained from a sol-gel derived siliceous network to which oxyethylene units are covalently grafted by means of urea or urethane cross-linkages. The bright photoluminescence is ascribed to an unusual convolution of distinct emissions originated in the NH groups of the urea or urethane…