Materials Literature
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The mechanical and structural properties of the tetrahedral amorphous carbon (ta-C) films deposited by the filtered cathodic vacuum arc technique on silicon at room temperature have been studied over the carbon ion energy range 15–200 eV. High (about 80% or higher) sp3 bond fractions were obtained for almost all ion e…
Bismuth sodium titanate, (Bi 1/2 Na 1/2 )TiO 3 (BNT)-based solid solution, (1- x )(Bi 1/2 Na 1/2 )TiO 3 – x 1/2(Bi 2 O 3 ·Sc 2 O 3 ) [BNST-100 x ], was studied in order to determine its dielectric, ferroelectric and piezoelectric properties as a new group of lead-free piezoelectric ceramics. Measurements of dielectric…
Abstract Data are presented from tests of the stress relaxation response of a polycarbonate under torsional deformations. Tests were performed on samples over a range of strains from 0.0025 to 0.08, temperatures from 30 to 135°C and aging times from 1800 to 64,800 s. Individual data sets at each strain, temperature an…
We report a structural evolution analysis of the long-range and local order and disorder of lead scandium niobate (PSN) down to 10 K, using a combination of neutron and x-ray diffraction on powder and single crystals. The structure of PSN is discussed and compared with those of simple perovskite compounds and . In PSN…
Crystal orientation dependence of piezoelectric properties has been calculated phenomenologically for lead zirconate titanate (PZT) in the three-dimensional space. The calculation has been made for tetragonal PZT 40/60 (40% PZ and 60% PT) and rhombohedral PZT 60/40 compositions. The maximum longitudinal piezoelectric…
Electrospray mass spectroscopy has finally provided proof for the formation of oxomanganese(v) complexes such as 1 under the conditions of the Kochi-Jacobson-Katsuki epoxidation. Collision of 1 with olefins or sulfides in the gas phase regenerates the initial (salen)MNIII complexes by transfer of the oxygen atom.
${}^{55}\mathrm{Mn}$ NMR experiments were carried out at 1.3--4.2 K on six samples of lanthanum manganites, with a hole doping concentration ranging from the antiferromagnetic-insulator to the ferromagnetic-conductor region of the phase diagram. The dependence of the resonance frequencies on external fields is either…
This paper deals with molecular materials resulting from the chemical and electrochemical molecular assemblies of organic and inorganic precursors such as organic donors derived from TTF, organic nitronyl nitroxide radicals, decamethylferrocenium, metal bis(dithiolate), metal bis(dithiolene), polyoxometalates, and hex…
N-Acetylneuraminic acid (Neu5Ac) is the precursor of sialic acids, a group of important molecules in biological recognition systems. Biosynthesis of Neu5Ac is initiated and regulated by its key enzyme, UDP-N-acetylglucosamine 2-epimerase (UDP-GlcNAc 2-epimerase, EC 5.1. 3.14)/N-acetylmannosamine kinase (ManNAc kinase,…
The magnetotransport and magnetic properties of epitaxial ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ thin films grown on (001)-oriented MgO substrates by pulsed-laser deposition have been investigated. The magnetoresistance (MR) exhibits a peak around the Verwey transition ${(T}_{\ensuremath{\nu}})$ as has also been reported…
The characteristic length scales of the structure and fractal behavior of a thixotropic colloidal suspension of synthetic clay were studied by using a combination of small-angle neutron and x-ray scattering and static light scattering. At the same time, macroscopic mechanical behavior at rest was characterized by mean…
We report on the magnetoresistive properties of all-oxide tunnel spin valves in which electrodes of mixed valence manganites (La 0.7 Sr 0.3 MnO 3 ) are separated by a thin insulating layer. The structures were prepared by Pulsed Laser Deposition and several tunnel barriers were used including PrBa 2 (CuGa) 3 O 7 , CeO…
(Ba,Sr)TiO3 (BST) thin films grown by chemical vapor deposition and with platinum (Pt) top and bottom electrodes have been characterized with respect to the leakage current as a function of temperature and applied voltage. The data can be interpreted via a thermionic emission model. The Schottky approximation accounts…
The temperature- and field-dependent permittivities of fiber-textured Ba0.7Sr0.3TiO3 thin films grown by liquid-source metalorganic chemical vapor deposition were investigated as a function of film thickness. These films display a nonlinear dielectric response under conditions representative of those encountered in dy…