Materials Literature
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In concentrated glucose glasses with water contents between 10 and 30 wt %, an indication for a transition in mobility of the sugar protons above the glass transition temperature is observed, using proton magnetic resonance techniques. The first transition in mobility is positioned at the glass transition temperature…
The electrochemical behavior of cobalt 5,10,15,20-tetrakis ( α, α, α, α-2-pivalamidophenyl)porphyrin (Co II TpivPP) was examined in benzonitrile solutions. The electrochemical responses were changed significantly by the addition of 1-methylimidazole which coordinates once to the Co(II) and twice to the Co(III) porphyr…
The novel dendrimers consisting of a pi-conjugated backbone, the dendritic polyphenylazomethines (DPAs), were synthesized by the convergent method via the dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained DPAs have a high solubility unlike the conventional…
The effects of chain end modification on freely standing amorphous polyethylene thin films with a thickness 2 R g to 4 R g (radius of gyration) are studied by a Monte Carlo (MC) simulation on a high coordination lattice. The rotational isomeric state (RIS) model is incorporated into the simulation as short-range inter…
A procedure for obtaining hydromagnesite is described. The process involves the formation of a Mg(HCO 3 ) 2 solution by carbonation of a MgO-containing residue slurry and further precipitation of hydromagnesite by addition of pure magnesium oxide as the precipitating agent. The solid residues generated can be landfill…
Microwave irradiation of racemic cis -[Ru(bpy) 2 (Cl) 2 ] (bpy = 2,2‘-bipyridine) or racemic cis -[Ru(phen) 2 (Cl) 2 ] (phen = phenanthroline) with either ( R )-(+)- or ( S )-(−)-methyl p -tolyl sulfoxide yielded the ruthenium bis(diimine) sulfoxide complexes with a high level of asymmetric induction (73−76% de). Ster…
The reaction of benzaldehyde with excess pyrrole at room temperature in the absence of solvent affords a mixture of meso-substituted polypyrranes species. After separation by column chromatography, these may be used to prepare a range of calix[4]phyrin macrocycles by condensation with acetone under conditions of acid…
Polybutadiene−polylactide block copolymers were prepared using well-defined hydroxy-terminated polybutadiene (PBD-OH). PBD-OH samples were reacted with AlEt 3 at various [PBD-OH] 0 /[AlEt 3 ] 0 ratios to form the corresponding aluminum alkoxide macroinitiators. Controlled polymerization of lactide was performed using…
Silver is known to strongly affect the adsorptive properties of some zeolites. It is also known that thermal vacuum dehydration of some argentiferous zeolites leads to the formation of charged silver clusters within the zeolite. In this work we have synthesized silver zeolites of the types Y, X, and low-silica X. The…
In continuing studies of the effect of solvent and molecular structure on the behavior of photochromic and thermochromic dye molecules, especially spiropyran (SP)−merocyanine (MC) interconversions, we have examined a series of 6‘-nitrobenzoindolinospiropyrans (6-nitro-BIPS) with varying N-functionalities (R = CH 3, CH…
We examine first-order perturbative results based on jellium for the surface energy of slabs of simple metals, using various local pseudopotentials (Ashcroft, Heine-Abarenkov and evanescent core). The difference between the pseudopotential and the jellium potential is averaged along the plane parallel to the surface.…
We study the vicinal surface with adsorption below the roughening temperature, using the restricted solid-on-solid model coupled with the Ising model. We calculate the step tension $γ$ and the step-interaction coefficient $B$ by employing a variant of the density matrix algorithm. We find a ``stiffening transition'' a…
TiO 2 films cast on conducting glass plates were modified by adsorbing gold nanoparticles (5 nm diameter) from a toluene solution. Selective formation of Au islands and larger particles on the TiO 2 surface could be seen from transmission electron micrographs and AFM images. Although the adsorbed Au particles are larg…
Poly(vinyl alcohol)/sodium montmorillonite nanocomposites of various compositions were created by casting from a polymer/silicate water suspension. The composite structure study revealed a coexistence of exfoliated and intercalated MMT layers, especially for low and moderate silicate loadings. The inorganic layers pro…
The two-photon absorption (TPA) coefficient (β) and third-order nonlinear optical susceptibility (χ ⟨3⟩ ) of Zn 1- x Ag x Se ( x = 0.08,0.10,0.20) crystals were investigated using the transmission and degenerate four-wave mixing methods. The experimental results show that the real and imaginary parts of the third-orde…
Carbonated hydroxyapatites (HAPCO 3 Na) and fluoroapatites (FAPCO 3 Na) containing sodium ions have been precipitated by the hydrothermal method. The effect of carbonate and sodium substituted for phosphate and calcium respectively on the dipolar mobility of the OH - and F - ions located inside the apatitic channels o…
We have grown heteroepitaxial thin film structures composed of various transition metal oxides such as the colossal magnetoresistance manganites, superconducting cuprates, ruthenates as well as insulating titanates on SrTiO<SUB>3</SUB>, NdGaO<SUB>3</SUB> and LaAlO<SUB>3</SUB> substrates using a UHV laser molecular bea…
Summary Vanillyl and veratryl alcohols were used as monomeric lignin model compounds in experiments aiming to enhance the understanding of the lignin oxidation mechanisms involved in the oxygen delignification in acidic media catalysed by [PMo 7 V 5 O 40 ] 8− (HPA-5) heteropolyanion. Based on the model compound experi…
A new disk-shaped amphiphilic dendrimer has been synthesized by attaching sixty-four 12-hydroxydodecanoic acid chains to a fourth generation poly(amido amine) (PAMAM) dendrimer core. Surface pressure and surface potential−area isotherm measurements have shown that the dendrimer forms a stable monolayer at the air/wate…
In this paper we present embedded-cluster calculations on singly charged and neutral oxygen vacancies (or F centres) in the oxide perovskite BaTiO 3 . The simulations include Hartree-Fock theory with MP2 corrections and density-functional-theory calculations for a central quantum defect cluster and a pair-potential de…