Materials Literature
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The piezoelectric and dielectric constants for Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT, 70/30) films with different orientations were measured. PMN–PT films were deposited on Pt(111)-passivated silicon substrates using a modified sol–gel process. The room temperature dielectric constants K for the {100}-oriented films were 25…
Chloromethylated poly(styrene) and chloropropylated silica gel have been reacted with α,ω-diamines to give diamine modified catalyst supports which have then been covalently attached to iron(III) tetrakis(pentafluorophenyl)porphyrin (FeTF5PP). In this way the diamino groups provide a simple linker/spacer unit between…
Thin ultradisperse diamond (UDD) layers deposited from a water suspension are studied by optical and x-ray photoelectron spectroscopy (XPS). The effective band gap determined by the 104-cm−1 criterion for ozone-cleaned UDD is 3.5 eV. The broad structureless photoluminescence band (380–520 nm) is associated with radiat…
The effects of hydrogen in type 310 stainless steel on the disorder of passive films and pitting susceptibility have been investigated. It is found that hydrogen decreases the breakdown potential, facilitates the pitting initiation and increases the pit density and growth rate. The passive films are found to exhibit n…
Deposition processes of chromium (Cr) species for the system chromia-forming alloy metallic interconnect/Sr-doped (LSM) electrode/3 mol % (TZ3Y) electrolyte have been investigated at 900°C with no air flow ( i.e. , the electrode was exposed to open air). With air flow, the deposition of Cr species took place preferent…
Solid oxide fuel cell (SOFC) reactions with a diluted dry methane feed were studied from chemical equilibrium analysis. The rate of carbon deposition and the composition of an anode gas mixture in equilibrium were predicted as a function of current density by minimizing the total Gibbs free energy of a system with 21…
The photodynamic activities of the free-base 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMP) and their metal complexes with zinc(II) (ZnTMP), copper(II) (CuTMP) and cadmium(II) (CdTMP) have been compared in two systems: reverse micelle of n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate/water bearing photooxidizab…
The electrical conductivity and the mean transport number of pyrochlore-type 0.03, 0.05) and were systematically studied as a function of temperature under wet hydrogen and oxygen atmospheres Under wet hydrogen atmosphere, pure proton conduction was observed below 873 K for both and systems. The proton conductivities…
Microtubules of polypyrrole (PPy) were synthesized by an electrochemical template-free method in the presence of β-naphthalenesulfonic acid (β-NSA) as a dopant for the first time. The influence of electrochemical polymerization conditions, such as material of the working electrode, the concentration of β-NSA and pyrro…
ABSTRACT: With the use of Fourier Transform Infrared (FTIR) analysis applied to methylcellulose (MC) films, the hydrogen bonding formation between MC‐MC molecules and between MC and a series of different‐molecular‐weight PEGs was studied. The spectra of the films were interpreted in terms of the symmetry distortion of…
The major linear and nonlinear electric properties of urea and thiourea have been calculated at different levels of approximation with respect to the treatment of the electron correlation contribution. The basis set saturation effects were studied by comparing the results computed in three different basis sets of incr…
The phosphors of high luminous efficiency for plasma display panel (PDP) applications must have high purity, single phase, uniform particle size, and clean surfaces. Photoluminescence characteristics of europium-doped yttrium oxide phosphors of spherical shape as well as optimum synthetic conditions for maximal lumine…
The time evolution of the free surface of asymmetric diblock copolymers of polystyrene and poly(methyl methacrylate) on a strongly interacting surface was studied with atomic force microscopy. The surface morphology underwent morphological transitions to satisfy commensurability conditions. These transformations were…
Nickel sorption in illite suspensions was studied as a function of pH (4.5–8.0), reaction time (3 h, 24 h, and 1 wk) and ionic strength ( and 0.003 M ) using x‐ray absorption spectroscopy (XAS) to characterize the Ni sorption complexes formed. The formation of Ni‐Al layered double hydroxide (LDH) phases was observed a…
Based on symmetry breaking steps under one-pot conditions, simple molybdenum oxide-based building blocks initially assemble to 'giant molecular wheels' in a fast process followed by further slower assembly processes leading stepwise to more complex mesoscopic architectures including spherical ones and finally to those…
Nanocomposites of polyaniline (PANI) and the semiconducting metal sulfides CdS and Cu2S were prepared from the respective metal trifluoromethanesulfonates co-dissolved in N-methylpyrrolidone. Metal sulfide particles with typical diameters of 1–2 nm formed in situ upon addition of Li2S; the nanocomposites were subseque…
Computer modelling techniques are used to investigate the surface properties and defect chemistry of the La2NiO4 material. Relaxed surface structures and energies are calculated for the low index planes which are used to predict the equilibrium crystal morphology. The {111} surface is calculated to dominate in the abs…
Dielectric spectroscopy is one of the most commonly used techniques for the investigation of the dynamic response of glass-forming materials. The tremendous slow-down of the particle motions when approaching the glass transition and especially the fast processes in glass-forming materials, which have come into the foc…
SUMMARIES Two samples of pure cellulose of different degree of polymerisation values were submitted to oxidation degradation by a specific agent (sodium metaperiodate) and by a non-specific agent (sodium hypochlorite). The degradation process was monitored by viscosity measurements in order to check the degree of poly…
The formation and growth of gas-made silica particles by co-agulation and sintering is investigated theoretically. A model for the characteristic time for silica sintering is proposed defining a minimum primary particle diameter above which macroscopic expressions are applied. The value of the minimum primary particle…