Materials Literature
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The dihydroporphyrazinediol 8, which was prepared by Linstead macrocyclisation of 2,5-diiminopyrrolidine with 3,4-bis(4-tert-butylphenyl)pyrroline-2,5-diimine, followed by TFA demetallation and OsO4 tetroxide mediated dihydroxylation, underwent reaction with Ni(OAc)2 at 100 °C in the presence of air to give the novel…
The reaction Fe+NO2→FeO+NO was studied by the pulsed two-photon dissociation at 248 nm of ferrocene vapour to produce Fe atoms in an excess of NO2 and He bath gas. Atomic Fe was then monitored by time-resolved laser-induced fluorescence spectroscopy at 248.3 nm [Fe(x5F05–a5D4)], yielding k(192<T/K<471)=(4.84-1.10+1.24…
To investigate the effect of the hydrophilic and hydrophobic microdomain structure on blood compatibility, a series of interpenetrating polymer networks (IPNs) composed of hydrophilic polyurethane (PU) and hydrophobic polystyrene (PS) was prepared. One series was prepared with varying cross-link densities of each netw…
Spontaneous removal of monocarboxylic (formic, acetic, propionic or butyric) acids accompanying dehydration of the corresponding chitosan salts was observed from X-ray fiber diffraction diagrams obtained during the storage of these salts for a given period of time. The first three salts were prepared by immersing a te…
The biodegradable polymers of poly(DL-lactide-co-glycolide) (PLGA) and poly(ethyleneglycol) (PEG) have come into use in the last few years for the control of the release of drugs. The incorporation of units of PEG produce an increased in vivo half life of the microparticles. The methoxylation of the PEG allows a contr…
The self-consistent full-potential LMTO method was used to study the electronic properties of the new hexagonal phases Ti3AlC2 and Ti3AlN2, and their chemical stability was compared with the stability of the isostructural compound Ti3SiC2 on the basis of cohesive energy calculations.
Poly-quasicrystalline samples of an icosahedral Al-Cu-Fe alloy have been deformed in compression tests under constant-strain-rate conditions at temperatures ranging from room temperature up to 1020 K (T m ≈ 1150 K, where T m is the melting temperature). The activation volumes, which were measured by performing load re…
Abstract Removal of SO 2 from the emissions of coal‐fired boilers produces by‐products that often consist of CaSO 4 , residual alkalinity, and coalash. These by‐products could be beneficial to acidic soils because of their alkalinity and the ability of gypsum (CaSO 4 ·2H 2 O) to reduce AI toxicity in acidic subsoils.…
1.1. Homogenization and Second Grade Media. The aim of homogenization methods is to replace a heterogenous material by a homogenous equivalent one endowed with effective properties. The now well-established results of classical homogenization theory [15] are generally based on the assumption of constant mean fields [1…
The structure of MO-TeO2 (M=Mg, Zn, Sr, Ba and Pb) glasses has been studied by means of 125Te static NMR technique. The fraction of TeO4 trigonal bipyramid (tbp), N4 decreased and that of TeO3 trigonal pyramid (tp), N3 increased almost linearly up to 33.3mol% MO and rapidly in the range of 33.3 to 40mol% MO, with incr…
Oxygen surface exchange was measured for Y 0.2 Ce 0.8 O 2 − x (YDC) and Y 0.15 Zr 0.85 O 2 − y (YSZ) over a wide range of oxygen partial pressures ( 7.3 × 10 − 21 to 0.17 bar ) by isotope oxygen exchange ( 18 O / 16 O ) using secondary‐ion mass spectrometry analysis at 973 K . Diffusion depth profiles of 18 O in YDC a…
Tetraalkyl and dialkyl derivatives, where alkyl=ethyl and propyl, of the organic electron donor molecule bis(ethylenedithio)tetrathiafulvalene, BEDT-TTF or ET, have been synthesized via the Diels-Alder approach. Several cation-radical salts of these new donors have been prepared and structurally characterized, and fou…
Pb 2 MgWO 6 is an ordered perovskite or elpasolite that undergoes a phase transition from a cubic paraelectric phase to an orthorhombic antiferroelectric phase below 310 K. Through an analysis of the electronic structures of both the high and low temperature phases using high level band structure methods, the nature o…
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Addition of a suspension of exfoliated titanate nanosheets into an Al13 pillaring solution produced a novel pillared structure associated with double layers of Al13 cations, which can be converted to a mesoporous alumina-pillared titanate with a 2.4 nm spacing by subsequent heat-treatment.
"In-situ" real time observation of the ferrite nucleation at nonmetallic inclusions has been successfully made at elevated temperatures with a confocal scanning laser microscope. The nucleation site, nucleation temperature, and/morphological change of the precipitates and ferrite can be sequentially determined as the…
Porous vanadium oxide materials were prepared by electrochemical deposition in the presence of surfactants. Both scanning electron microscopy and ac impedance results indicated a large increase in surface area compared with a sample prepared without surfactants. X‐ray diffraction and infrared spectroscopy results indi…
Article Revisiting the Complexity of Finding Globally Minimum Energy Configurations in Atomic Clusters was published on January 1, 1999 in the journal Zeitschrift für Physikalische Chemie (volume 211, issue 1).
Si nanocrystallites embedded in a silica matrix have been prepared by the sol-gel route using triethoxysilane as the precursor. The different steps of formation of silicon during thermal treatment of the gels were observed by X-ray diffraction, Raman and 29 Si MAS NMR spectroscopy. The gels were first pre-heat-treated…
The new podand ligand hydrotris[3-(6-methyl)pyridin-2-ylpyrazol-1-yl]borate [L1]– was prepared which contains three bidentate pyrazolyl/pyridine arms attached to a {BH}– head-group. This ligand differs from an earlier ligand hydrotris[3-(2-pyridyl)pyrazol-1-yl]borate [L2]– by the presence of methyl groups attached to…