Materials Literature
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In order to test whether the low-energy excitations explored extensively in amorphous solids are indeed universal, all measurements published on the low-temperature thermal conductivity and acoustic attenuation in these solids have been reviewed, on a total of over 60 different compositions. The ratio of the phonon wa…
Removal of lead from aqueous solution with chitosan/PVA (poly(vinyl alcohol)) hydrogel beads was studied in batch adsorption experiments at various solution pH values (2−7.6). Lead adsorption on chitosan/PVA beads was found to be strongly pH-dependent and displayed a maximum uptake capacity at pH around 4 and a minimu…
A giant low-frequency dielectric constant ( epsilon 0 approximately 10(5)) near room temperature was observed in Li,Ti co-doped NiO ceramics. Unlike currently best-known high epsilon 0 ferroelectric-related materials, the doped oxide is a nonperovskite, lead-free, and nonferroelectric material. It is suggested that th…
We address the problem of the percolative phase separation in polycrystalline samples of ${\mathrm{Pr}}_{0.5\ensuremath{-}\ensuremath{\delta}}{\mathrm{Ca}}_{0.2+\ensuremath{\delta}}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ for $\ensuremath{-}0.04<~\ensuremath{\delta}<~0.04$ (hole doping n between $0.46$ and $0.54).…
Abstract For Abstract see ChemInform Abstract in Full Text.
A number of mono(imidazole)-ligated complexes of perchloro(meso-tetramesitylporphyrinato)iron(III), [Fe(TMP)L]ClO(4), have been prepared, and their spin states have been examined by (1)H NMR, (13)C NMR, and EPR spectroscopy as well as solution magnetic moments. All the complexes examined have shown a quantum mechanica…
Two new isostructural compounds, dichlorobis(1-(2-chloroethyl)tetrazole)copper(II) (1) and dibromobis(1-(2-chloroethyl)tetrazole)copper(II) (2), have been prepared. The synthesis, characterization, and spectral and magnetic properties as well as the crystal and molecular structures of 1 and 2 have been studied. Both c…
Certain ionic materials containing dissimilar mobile cations exhibit the nonlinear behavior of diffusion-related properties, called the mixed mobile ion effect. In these materials only cations participate in the diffusion process. In this paper we report on the mixed mobile ion effect in fluoride glasses, where anions…
Soon after the discovery of carbon nanotubes, it was realized that the theoretically predicted mechanical properties of these interesting structures — including high strength, high stiffness, low density, and structural perfection — could make them ideal for a wealth of technological applications. The experimental ver…
Artificial antenna systems and reaction centres synthesized in our laboratory are used to illustrate that structural and thermodynamic factors controlling energy and electron transfer in these constructs can be modified to optimize performance. Artificial reaction centres have been incorporated into liposomal membrane…
Based on a relaxation equation for the second rank alignment tensor characterizing the molecular orientation in liquid crystals, we report on a number of symmetry-breaking transient states and simple periodic and irregular, chaotic out-of-plane orbits under steady flow. Both an intermittency route and a period-doublin…
A new aromatic periodic mesoporous organosilica material containing benzene functional groups that are symmetrically integrated with three silicon atoms in an organosilica mesoporous framework is reported. The material has a high surface area, well-ordered mesoporous structure and thermally stable framework aromatic g…
Nucleation and growth kinetics of ammonium sulfate are determined using a 1.5-L cooling batch seeded crystallizer, a rigorous mathematical model of the process, and a nonlinear optimization program. Supersaturation and crystal size distribution are employed as the major outputs of the model in the optimization objecti…
Samples of poly(syndiotactic styrene- co -butadiene) (sPS−B) have been prepared using methylalumoxane (MAO) activated CpTiCl 3 under a range of experimental conditions. Copolymerization activities were low (24−36 kg mol -1 of cat. h -1 ) and nearly constant over the range of polymerization temperatures investigated (2…
Using the Monte Carlo lattice-simulation technique, we present numerical evidence of the formation of gyroid and nongyroid tricontinuous cubic phases in high polymeric systems of ABC/A/C triblock copolymer and homopolymer blends. By increasing the volume fraction of homopolymer, a remarkable phase sequence G (gyroid)…
The low-temperature specific heat of single-walled carbon nanotubes (isolated and bundled) and multiwalled carbon nanotubes is calculated within force-constant dynamical models. It is shown that, due to the quadratic dependence of the frequency $\ensuremath{\omega}$ of the transverse-acoustic phonons on the wave numbe…
We develop an efficient simulation scheme to study a model suspension of equally sized colloidal hard spheres and nonadsorbing ideal polymer coils, both in bulk and adsorbed against a planar hard wall. The many-body character of the polymer-mediated effective interactions between the colloids yields a bulk phase diagr…
Abstract Fluorescence was used to characterize the glass transition in thin and ultrathin supported polymer films with common chromophores. The temperature dependence of the fluorescence intensity exhibits a transition or break upon cooling from the rubbery state to the glassy state, and this is identified as the glas…
Electronic states of P donors in Si nanocrystals (nc-Si) embedded in insulating glass matrices have been studied by electron spin resonance. Doping of P donors into nc-Si was demonstrated by the observation of optical absorption in the infrared region due to intraconduction band transitions. P hyperfine structure (hfs…
We have used density functional calculations on model peptides to study conformational effects on (15)N, (13)C alpha, (13)C beta, and (13)C' chemical shifts, associated with hydrogen bonding, backbone conformation, and side-chain orientation. The results show a significant dependence on the backbone torsion angles of…