Materials Literature
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The spin- and orbital-moment magnetization form factors in NiO have been measured using magnetic x-ray scattering. The polarization analysis of nonresonant magnetic-scattering intensities has evidenced a large contribution from the orbital moment to the total magnetization. In the antiferromagnetic phase, the orbital…
pdrK encodes a pyridoxine (PN)/pyridoxal (PL)/pyridoxamine (PM) kinase thought to function in the salvage pathway of pyridoxal 5'-phosphate (PLP) coenzyme biosynthesis. The observation that pdxK null mutants still contain PL kinase activity led to the hypothesis that Escherichia coli K-12 contains at least one other B…
Corrosion pits on stainless steel often grow in such a way as to undermine the original surface, and, consequently, a thin layer of metal and oxide is left over the growing pit cavity. These pit covers develop a porous, lacelike structure, and a model for the development of this structure is described. Calculations ba…
I discuss the chemistry and physics of semiconductor nanocrystals. Various physical size regimes are outlined in both spectroscopic and kinetic properties. There is a solvation effect on electron transport kinetics due to the electric field of the moving carrier. The importance of chemical synthesis is emphasized with…
Pt-based metallizations using different adhesion layers (Ti, Zr and Ta) were studied for use as electrodes for ferroelectric thin films on oxidized silicon substrates. Different ways of oxidizing the adhesion layers prior to ferroelectric film growth are compared, with regard to obtaining stable, adherent Pt films of…
Abstract Nanomorphological structure of well-crystallized Georgia and poorly crystallized North Queensland kaolinite particles have been compared using field emission scanning electron microscopy (SEM) and atomic force microscopy (AFM). In general, there is good agreement in information from the 2 very different imagi…
Self-assembling of nanocrystals involves organization of nanocrystals encapsulated by protective compact organic molecules into a crystalline material. The adsorbed molecules not only serve as the protection layer for the nanocrystals but also provide the dominant cohesive interactions (or “bonding”) sustaining the na…
The lifetime of the (d z 2,d x 2 - y 2 ) metal excited state of nickel(II) 5,10,15,20-tetra- tert -butylporphyrin (NiT( t -Bu)P) exhibits an extraordinary dependence on solvent dielectric properties and temperature. At room temperature, the excited-state deactivation time varies from 2 ps in highly polar solvents to a…
Abstract Au nanoparticles can be deposited on MCM-41 by chemical vapor deposition (CVD) of dimethyl gold acetylacetonate. They exhibit high catalytic activities for the oxidation of CO and of H2 at low temperatures, below and above 273K, respectively.
Electron and energy transfer processes from CuI MLCT excited states are reviewed. New results demonstrate clearly that these excited states undergo oxidative electron transfer quenching and energy transfer processes. The yields and dynamics of these processes have been spectroscopically quantified. Interfacial electro…
A series of head to tail alkyl-substituted oligothiophenes was synthesized by a stepwise synthesis based on the repetitive use of the Suzuki coupling reaction between a stable thienyl boronic ester and the appropriate chloride-protected precursors catalyzed by Pd[P(C 6 H 5 ) 3 ] 4, under mild conditions. By this metho…
The melting properties of aluminum are calculated from first-principles molecular-dynamics simulations using density-functional theory in the local-density approximation. We calculate a melting temperature of 890 K at zero pressure, to be compared to the experimental value of 933 K. An elaborate discussion of the tech…
The dielectric response in relaxor ferroelectrics is analyzed in the framework of a model for the polarization dynamics in the presence of polar clusters. We associate the origin of polar clusters with atoms displaced from their centrosymmetrical positions even above ${T}_{c}.$ Their collective hopping in multiwell po…
Epitaxial films of magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ have been grown on ${\mathrm{SrTiO}}_{3}$ (100) and sapphire (\ensuremath{\alpha}-${\mathrm{Al}}_{2}{\mathrm{O}}_{3},$ 0001) substrates by pulsed laser deposition, and they exhibit crystal orientations of [100] and [111], respectively. Films of both or…
We show that the organic salt 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate, originally developed for electro-optic applications, is also a very interesting material for phase-matched parametric interactions such as frequency-doubling and optic parametric oscillation in the near infrared. These favorable prop…
An array of analytical techniques comprising powder X-ray diffraction, solid-state NMR spectroscopy, high-resolution transmission electron microscopy, nitrogen adsorption, and UV/vis diffuse reflectance spectroscopy has been applied to study the incorporation of indium phosphide semiconductor inside MCM-41 materials b…
This study was focused on the conformational characterization of Bombyx mori silk fibroin in film, fiber and powder form by means of Fourier transform Raman spectroscopy. Native and regenerated silk fibroin films prepared by casting dilute silk fibroin solutions (<1%, w/v) display characteristic conformationally sensi…
Transport properties of ${\mathrm{La}}_{0.75}{\mathrm{Ca}}_{0.25}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}{\mathrm{O}}_{3+y}$ ceramics are examined for ``$x$'' values from 0 to 0.05. Dramatic changes are observed in the resistivity and its temperature dependence as ``$x$'' increases above about 0.04. Temperatu…
Crack deflection and the subsequent growth of delamination cracks can be a potent source of energy dissipation during the fracture of layered ceramics. In this study, multilayered ceramics that consist of silicon nitride (Si 3 N 4 ) layers separated by boron nitride/silicon nitride (BN/Si 3 N 4 ) interphases have been…
Quantum ferroelectric and ferroelectric relaxor behavior has been found in $({\mathrm{Sr}}_{1\ensuremath{-}1.5x}{\mathrm{Bi}}_{x}){\mathrm{TiO}}_{3}.$ For $x<~0.0267,$ the quantum ferroelectric relationship ${T}_{{\ensuremath{\varepsilon}}_{m}}\ensuremath{\propto}(x\ensuremath{-}{x}_{c}{)}^{1/2}$ holds with ${x}_{c…