Materials Literature
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Abstract A new polycarboxylate ligand H 5 L has been synthesized by the attachment of five benzoate subunits onto a diethylenetriamine framework. Seven p K a values have been determined by potentiometry, spectrophotometry and NMR spectroscopy as 1.9(2), 2.8(2), 3.87(5), 4.58(6), 4.87(6), 9.19(6) and 11.68(5), the firs…
Abstract In this paper the fundamentals of the asymmetric elasticity theory are used to consider one‐ and two‐dimensional boundary‐value problems: shear deformation of elastic infinite plane layer(plate); torsion of a ring rigidly fixed at the external contour due to rotation of the inner one; deformation of a plane w…
We have demonstrated that a static permittivity of potassium tantalate is dramatically enhanced by band-to-band excitation at low temperatures. A critical behavior has been observed in the relaxation time and the oscillator strength of its Debye-type dispersion. Two models, considering photoinduced mesoscopic clusters…
Measurements of the energy distributions and energy-resolved polarizations of electrons ejected by incident polarized ${\mathrm{He}}^{+}$ ions are used to probe the dynamics of ${\mathrm{He}}^{+}$ ion neutralization at clean Al(100), Au(100), and Cu(100) surfaces for incident ion energies in the range 10--500 eV. The…
This work investigates the photoluminescence (PL) properties of the cubic chloroperovskite NH 4 MnCl 3 . Like in most concentrated materials, the Mn 2+ PL which is located at 2.10 eV at T = 10 K strongly depends on the temperature. Optical absorption (OA), emission, and excitation spectroscopy, as well as lifetime mea…
The molecular dynamics of a side-chain polymer liquid crystal with a poly(methyl acrylate) backbone and a (p-alkoxy-phenyl)-benzoate mesogenic group have been studied in the unaligned state as a function of temperature and pressure using dielectric spectroscopy. Polarizing optical microscopy, differential scanning cal…
Abstract A new adsorbent for heavy metal ions, cys‐chitin, was produced by modifying chitin in THF with L ‐cysteine in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FTIR spectra analysis. The adsorption properties of cys‐chitin for Cu II , Cd II , Pb II , Zn II , an…
Low temperature (7 K) absorption spectra of polycrystalline sintered ceramic Lu 2 O 3 :Eu 3+ were recorded between 3950 and 50000 cm −1 . There are two different intrinsic Eu 3+ sites, C 2 and S 6 (C 3i ), in this host. A total of 105 crystal-field (CF) energy levels were assigned and fitted to a semiempirical Hamilto…
Patterns and alignment of carbon nanotubes (CNTs) are particularly important for fabricating functional devices such as field emitters, scanning probes, sensors, and nanoelectronics. In this paper, the effects of various metal substrates on CNT growth are studied. Depending on the different growth mechanisms associate…
Using density-functional theory, we calculate the energy and electronic structure of a polyacetylene chain interacting with various carbon nanotubes. We find that polyacetylene chains are weakly attracted exohedrally or endohedrally to nanotubes. The equilibrium separation between the chain and the wall is close to 3.…
Abstract A 2,6‐dimethyl phenol‐dicyclopentadiene novolac was synthesized from dicyclopentadiene and 2,6‐dimethyl phenol, and the resultant 2,6‐dimethyl phenol‐dicyclopentadiene novolac was epoxidized to 2,6‐dimethyl phenol‐dicyclopentadiene epoxy. The structures of novolac and epoxy were confirmed by Fourier transform…
Abstract Lanthanide complexes with a one‐dimensional chain, [Ln 2 (dpdc) 3 (H 2 O) 2 ] n [Ln = La ( 1 ), Pr ( 2 ), Eu ( 3 ), Tb ( 4 ); dpdc = 2,2′‐diphenyldicarboxylate] were obtained by hydrothermal reaction of lanthanide( III ) chlorides and 2,2′‐diphenyldicarboxylic acid, and characterized by X‐ray diffraction. The…
Transition metals (Pt, Pd, Rh, Cr, etc.) are widely used as catalysts on \ensuremath{\gamma}- and \ensuremath{\eta}-alumina, two phases of ${\mathrm{Al}}_{2}{\mathrm{O}}_{3},$ but the catalytic activity of Cr on \ensuremath{\gamma}-alumina degrades rapidly. We report density-functional calculations that trace the orig…
Abstract A mathematical model to describe the molecular weight and polydispersity index ( Q ) in poly( L ‐lactide) (PLLA) thermal degradation has been developed. Based on the random chain scission mechanism, effects of temperature and time on the molecular weight and polydispersity index are included in this model. It…
Abstract In the extrusion manufacture of starch‐based thermoplastics, such as biodegradable packaging materials, glycerol is an effective additive as a plasticiser, that is, to diminish the brittle nature of the product and provide the desired extent of flexibility. However, the addition of glycerol may also affect th…
We have performed dielectric loss measurements at 1 kHz on thin films of isotactic poly(methyl methacrylate). A key distinction of our studies is that the samples measured were supported films with one free surface rather than films that have metallic electrodes covering both surfaces. This unique sample geometry allo…
BACKGROUND: It has been found recently that the MRI contrast agent superparamagnetic iron oxide (SPIO) localizes to aortic atherosclerotic plaques. We therefore asked whether SPIO might be used to monitor monocyte recruitment into aortic atherosclerotic plaques. METHODS AND RESULTS: Eleven female apo E knockout (K/O)…
First measurements of oxygen grain boundary diffusion coefficients in nanocrystalline yttria-doped ZrO(2) (n-ZrO(2).6.9 mol % Y(2)O(3)) are presented. The (18)O diffusion profiles measured by secondary ion mass spectroscopy are much deeper in the nanocrystalline specimens than in single crystals. An oxygen diffusivity…
Large-scale zinc oxide (ZnO) nanowires were grown via a simple chemical reaction involving water vapour. Electron microscopy observations reveal that the ZnO nanowires are single crystalline and grow along the c -axis ([001]) direction. Room temperature photoluminescence measurements show a striking blue emission at 4…
We report an x-ray absorption spectroscopic (XAS) study on thin films of ${\mathrm{La}}_{0.7}{\mathrm{Ce}}_{0.3}{\mathrm{MnO}}_{3}.$ The measurements clearly show that the cerium is in the Ce(IV) valence state, and that the manganese is present in a mixture of ${\mathrm{Mn}}^{2+}$ and ${\mathrm{Mn}}^{3+}$ valence stat…