Materials Literature
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Analysis of the point-contact spectroscopy (PCS) data on the new dramatic high-T$_c$ superconductor MgB$_2$ reveals quite different behavior of two disconnected $σ$ and $π$ electronic bands, deriving from their anisotropy, different dimensionality, and electron-phonon interaction. PCS allows direct registration of bot…
We calculate the electron exchange coupling for a phosphorus donor pair in silicon perturbed by a J-gate potential and the boundary effects of the silicon host geometry. In addition to the electron-electron exchange interaction we also calculate the contact hyperfine interaction between the donor nucleus and electron…
Structural relaxations in electronically excited poly(para-phenylene) are studied using many-body perturbation theory and density-functional-theory methods. A sophisticated description of the electron-hole interaction is required to describe the energies of the excitonic states, but we show that the structural relaxat…
On the basis of spectral-expansion Green's function theory, we theoretically describe the topography, polarization, and spatial-coherence properties of the second-harmonic (SH) local fields at rough metal surfaces. The spatial distributions of the fundamental frequency and SH local fields are very different, with high…
Well-defined rodlike and fiberlike SBA-15 mesoporous silicas have been selectively synthesized from an aqueous reaction mixture consisting of a commercial sodium silicate solution, P123 triblock copolymer and HCl. The morphologies and physicochemical properties of the products were found to be greatly affected by the…
The solid solution Nb x Ti 1 - x O 2 +δ has been synthesized by a sol−gel method with 0.0 ≤ x ≤ 0.1. Structural and microstructural properties have been studied by XPS, XRD, Raman spectroscopy, and TEM as a function of the Nb/Ti atomic ratio and thermal treatment temperature (600−900 °C). XRD analyses showed that a pe…
We report here a novel approach to synthesize chiral PANI nanofibers in an aqueous solution. This new approach requires the following conditions: (1) Polymerization was carried out in concentrated camphor sulfonic acid solutions. (2) Aniline oligomers were used to accelerate the polymerization reaction. (3) Ammonium p…
The surface energies and electronic structure of (111), (110), and (100) surfaces of ${\mathrm{CeO}}_{2}$ have been studied using the first-principles projector augmented-wave method within the local density approximation (LDA) and generalized gradient approximation (GGA) and are compared with molecular dynamics (MD)…
Four 3-D coordination polymers of lanthanide with a tetra(amino acid) ligand, 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrapropionic acid (H4L, 1), were synthesized. The structure of the Gd(III) complex was characterized. The fluorescence of the Eu(III) complex can be modulated by Ag+.
The implications of the entanglement concentration ( C e ) on the electrospinning process for a series of linear and branched poly(ethylene terephthalate- co -ethylene isophthalate) (PET- co -PEI) copolymers with weight-average molecular weights ( M w ) ranging from 11 700 to 106 000 g/mol and branching index values (…
Abstract A series of linear polyamides (P n MLM) derived from O ‐methyl‐protected L ‐malic acid and 1, n ‐alkanediamines with even n values ranging from 4 to 12 were prepared and fully characterized. L ‐Malic acid entered in the chain with a random orientation rendering essentially aregic polymers. P n MLM displayed o…
The practicality of using polysulfone as a host material for electro-optic polymer devices is demonstrated. For loadings of 15–25 weight %, r33 values of 53–55 pm/V were obtained at λ=1.06 μm. This corresponds to chromophore alignment efficiencies of up to 27%. Also, Mach–Zehnder devices demonstrated the implementatio…
Second-harmonic generation and thermal stability of hybrid photosensitive sol-gel films doped with a side-chain electro-optic chromophore have been studied. Nonlinear optic coefficient d33 has been derived for the cross-linked and noncross-linked sol-gel films. The d33 of the cross-linked hybrid sol-gel film shows hig…
The compositionally graded Ba1−xSrxTiO3 films with a fine compositional gradient from BaTiO3 to Ba0.70Sr0.30TiO3 were fabricated on LaNiO3-buffered Pt–Ti–SiO2–Si substrates by a sol-gel deposition method. After post-deposition annealing the graded films crystallized into a pure perovskite structure with their crystall…
Abstract An Erratum has been published for this article in Journal of Polymer Science Part A: Polymer Chemistry (2004) 42(10) 2575‐2576 Starlike, highly branched (A x B y A z ) macromolecules having from a few to 100 arms and molar masses up to 10 5 were prepared in three stages with the one‐pot, arms‐core‐arms method…
We show that the conventional consideration of the electron-field emission from nanocarbons cannot explain the experimentally observed results. We suggest a mechanism of the field emission occurrence from nanocarbons that can solve the existing puzzles. This mechanism implies two successive processes: (1) Tunneling th…
Adsorption of 4-biphenylmethanethiolate (BPMT) has been studied for different-sized gold nanoparticles, with mean diameters of 6, 11, 15, 27, 35, 43, and 97 nm, using surface-enhanced Raman scattering (SERS). Transmission electron microscopy (TEM) images and UV−visible absorption spectra were obtained to examine the m…
The sulfonation of polyaniline (PANI) films by nucleophilic addition of sulfite ion has been controlled through the polymer oxidation state under electrochemical control. The process was monitored by in situ electrochemical quartz crystal microbalance (EQCM), and the polymer oxidation was accomplished by electrode pot…
Abstract Relying on a model allowing to predict mechanical properties and acoustic absorption of a regular f.c.c stacking of hollow spheres, and on a functional analysis of acoustic liners for airplane engines, a methodology for optimal design of a taylored multifunctional material is proposed.
The reactivity of the sterically hindered organofluorosilane 2,6-Mes 2 C 6 H 3 -SiF 3 ( 1 ) (Mes = 2,4,6-trimethylphenyl) under hydrolytic conditions differs substantially from that of the corresponding organo chlorosilane. During the hydrolysis of 1 the combination of thermodynamic (increased Si−F bond strengths comp…