Materials Literature
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Time-of-flight secondary ion mass spectrometry (TOF SIMS) analyses have been performed on MoO3–Pr6O11 mixtures before and after their use in the selective oxidation of isobutene to methacrolein at 673 K. The three pure molybdate phases (Pr2MoO6, Pr2Mo3O12, Pr6MoO12) obtained independently by the citrate route have als…
The bidentate phosphine ligands bis(diphenylphosphino)acetylene and 1,4-bis(diphenylphosphino)benzene have been found effectively to stabilise polynuclear copper/chalcogenide/chalcogenolate cores, acting as intramolecular bridges between copper centres. The clusters [Cu16Se4(SePh)8(µ-1,4-Ph2PC6H4PPh2)4] 1 and [Cu25Te6…
Electrochemical impedance spectroscopy was used to probe the mechanism of copper deposition on silicon from dilute hydrofluoric acid solutions. Reaction parameters such as polarization resistance and space‐charge capacitance were evaluated using an equivalent circuit model. The electrochemical impedance technique was…
Kinetic models for the thermal degradation of poly(vinylbutyral) PVB/Al 2 O 3 and PVB/AlN composites, based on weight loss and evolved gas analysis (EGA), are presented. TG (sample weight loss) and FT-IR (mixture gas spectra) data were measured to elucidate the kinetic models using isothermal and nonisothermal approac…
Polymers containing labile silyl ester bonds along the backbone were synthesized via a transsilylation ester interchange reaction. The condensation of the bis(trimethylsilyl) esters of adipic acid and sebacic acid with several bis(silyl chloride)s gave trimethylsilyl chloride as the condensate and formed the new silyl…
Article Selective Transition-Metal Catalysis of Oxygen Delignification Using Water-Soluble Salts of Polyoxometalate (POM) Anions. Part I. Chemical Principles and Process Concepts was published on January 1, 1998 in the journal Holzforschung (volume 52, issue 3).
The mechanism of the partial oxidation of CH 4 was studied by a transient response analysis of a broadened pulse combined with either a step change or a sharp isotopic pulse. Over the unreduced NiO/SiO 2 catalyst, the reaction between CH 4 and O 2 occurs via the Eley−Rideal mechanism, CH 4 in the gas phase (or weakly…
We present a theoretical analysis of the influence of ambient pressure on single-bubble sonoluminescence (SBSL). By combining simulations of gas dynamics, mass diffusion theory, and stability analysis we find a narrow region of the parameter space where stable SBSL is possible. In particular, the theory predicts a 200…
Abstract A method for qualitative and quantitative analysis of scanning electron microscope (SEM) images forthe determination of sharpness is presented in this paper. Described is a procedure for qualitative analysis based on a software program called SEM Monitor that can be applied to research or industrial SEMs for…
The investigation in the cyclic behaviour of ultra-fine grained copper produced by severe plastic deformation was performed in fully reversed tension/compression under constant plastic strain amplitudes. It is shown that UFG copper possesses unusual fatigue properties such as a high saturation stress and a clearly pro…
A special class of nano-porous inorganic dielectrics, the silicon dioxide aerogels, with porosities >70% were prepared using single and two-step sol-gel processing and a supercritical drying method. Samples, pretreated at temperatures /spl les/800/spl deg/C for several hours, and with chemical surface modification by…
The structure of the catalytically active, reduced, form of the enzyme hydroxymethylbilane synthase (HMBS, Lys59Gln mutant) has been studied by Laue diffraction as the substrate, porphobilinogen (PBG), was fed to an immobilised crystal in a flow cell. Laue data at short time-scale time points (i.e. 1, 2, 4 and 8 min)…
We present results of computer simulations of polymer brushes (layers of polymer chains attached at one end onto an impermeable planar surface) under shear deformation at constant shear rate. As the first stage of calculations the behavior of a single brush was studied. The monomer density profile, the distribution of…
Evidence of a transformation from tetragonal to rhombohedral phases in a 80/20 mixture of lead ziconate titanate (PZT) (53/47) and lead magnesium niobate-lead titanate (PMN-PT) (65/35) was observed by x-ray diffraction, microstructural analysis, dielectric spectroscopy, and electrically-induced strain measurements. An…
We have measured the electrical resistivity and the Hall effect in D03-type (Fe1−xVx)3Al alloys with 0≤x≤0.38. When substituted by V, the electrical resistivity increases rapidly at low temperatures and shows an anomalous temperature dependence: an occurrence of a resistance maximum at or near the Curie point TC and a…
Synthesis of a monosubstituted ferrocene-based chiral Schiff’s base derivative with unusual mesomorphic behavior is reported namely the first metallomesogen which exhibits TGBA and blue phases apart from SC*, SA and N* phase transformations.
A novel and direct synthesis of hydroperoxy compounds from various types of conjugated olefins was established via cobalt(II) porphyrin-catalyzed hydroperoxygenation. The reaction of α,β,γ,δ-unsaturated carbonyl compounds, acrylic esters, α-substituted acrylic esters and styrene derivatives with molecular oxygen and t…
The reaction of p-bromo(triisopropyloxysilyl)benzene 2 with magnesium led to stable THF solutions of the corresponding Grignard reagent. The reaction of this latter with PCl3 or PhPCl2 allowed the preparation of phosphines 4 and 5 respectively. LiAlH4 reduction of 4 afforded phosphine 6. Compounds 4 and 6 have been tr…
The oxidation of 1-(substituted phenylazo)-2-hydroxynaphthalene-6-sulfonate dyes by oxoiron(IV) tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin (OFeIVTDCSPP) in aqueous solution is first-order in the concentration of the dye and of the oxoiron(IV) species over the pH range 6.93–12.68. The pH dependence of the second-or…
Fluoroalcohols [1,1,1,3,3,3-hexafluoropropan-2-ol (HFP), 2,2,2-trifluoroethanol (TFE) and 2-fluoroethanol (FE)], acting as Lewis acids, stabilize the π-conjugated, colored merocyanine forms of spiropyran and spirooxazine photochromic compounds as metal ions do.