Materials Literature
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We investigated the structural changes of carbon in diamond films deposited by microwave plasma-assisted chemical vapor deposition with various methane concentrations and substrate temperatures. They were studied by x-ray-absorption near-edge structure (XANES) at the C $K$ edge. The results on composition and structur…
Abstract The thermal stability of bentonites is of particular interest for containment barriers in nuclear waste storage facilities. The kinetics of smectite reactions have been investigated under laboratory conditions for some time. The variables of time, chemical composition and temperature have been varied in these…
The magnetic properties and the microstructure of Nd–Fe–B and Nd–Fe–Co–Ga–B die upset magnets produced from amorphous materials were studied. The Nd–Fe–B die upset magnets had fine polygonal Nd2Fe14B grains and showed magnetic anisotropy. The compositional modification and optimization of the die upset condition led t…
We have investigated the influence of the coarsening process on the complex shear modulus of three-dimensional aqueous foam. It is shown that the viscoelastic response is governed by a large spectrum of relaxation times and that the complex shear moduli measured as a function of frequency, at different foam ages, can…
A method for using in situ X‐ray absorption near edge spectroscopy to determine the composition of passive, transpassive, and nonreducible thin oxide films is described. The method is demonstrated by determining the composition of the passive films formed in pH 4.5, 0.1 M acetate buffer, on 100 Å thick Fe‐ y /Cr alloy…
This letter reports on the influence of a static electric field applied by metal electrodes on the agglomeration process of carbon black (CB) in epoxy resin. The growth of dendrites from the anode into the material is observed in situ by optical transmission microscopy. A percolating network is seen to form, combined…
The microstructure of transition aluminas obtained via the dehydration of boehmite has been characterized by using transmission electron microscopy (TEM). The presence of γ‐, δ‐, and θ‐aluminas was identified by using selected‐area electron diffraction. Modifications that resulted from the reordering of aluminum vacan…
Elastic constants for 12 mol% Ce‐doped tetragonal zirconia have been determined from peak shifts in neutron diffraction patterns recorded under applied uniaxial stress. When these diffraction data are combined with a measured value of Young's modulus, a complete set of elastic constants is obtained. The values are c 1…
A review of methods for soil extraction used in the United States is given starting from the early 1940s to today. With the use of multielement analyzers, primarily the inductively coupled plasma emission spectrometer (ICP‐AES), extraction procedures being adopted today are those with multielement capabilities, such a…
A symmetric, low-molecular-mass liquid crystal based on the oxadiazole ring was synthesized and characterized. The symmetric position of the heterocyclic group in the centre of the liquid crystal, bis(4-hexyloxyphenyl)4,4-(1,3,4-oxadiazole-2,5-diyl)dicarboxylate, yields a very rigid and non-linear mesogenic core. Desp…
A novel polymorph of VO2, designated VO2(C), has been prepared by dehydration of the new layered vanadium oxide hydrate, VO2·1/2 H2O. The hydrate is prepared in high yield as a single phase from the hydrothermal reaction of the hydrolyzate of VCl4and NaOH in a molar ratio of 1:4.5 for 96 hours at 200°C. The hydrate cr…
In this letter, we report the results for capacitance versus frequency measurements on a set of Ba0.5Sr0.5TiO3 (BST) capacitors with platinum electrodes (Pt) and varying BST film thicknesses. The study shows that Pt/BST interfacial capacitance is independent of frequency whereas the bulk dielectric constant has a powe…
1,4-Dioxan-2-one (DOXA) was polymerized by means of Zn L-lactate (ZnLac2) as catalyst in bulk. Upon systematic variation of the temperature, the reaction time and the monomer/catalyst (M/C) mole ratio the highest molecular weights were obtained at 100°C and M/C ratios between 2 000 and 4 000. However, long reaction ti…
The cobalt(III) complex of a Schiff base diquinone ligand CoIII(Cat-N-BQ)(Cat-N-SQ) undergoes an entropy-driven valence tautomeric equilibrium in solution yielding the CoII(Cat-N-BQ)2 species. This suggestion is supported by variable temperature electronic and 1H NMR spectra, as well as by solution magnetic susceptibi…
The cathodoluminescence of ZnO films deposited on Si substrates by reactive dc sputtering is investigated. Apart from the characteristic green emission band (522 nm) of ZnO, an ultraviolet (392 nm) band and a blue (430-460 nm) band have been observed. The x-ray diffraction and cathodoluminescent spectra reveal the dep…
Abstract This paper reviews recent studies on the mechanism of corona treatment of polyolefin films, specifically the chemical and physical changes of this process and the self‐adhesion mechanism. Corona discharge of polymeric films introduces polar groups into the surfaces, which increases the surface energy and, as…
A mathematical model has been developed to describe the dynamic heat and moisture transport behavior of clothing and its interaction with the human thermoregulation system under transient wear conditions. A modification of Gagge's two-node model is used to simulate the human physiological regulatory responses. In clot…
The growth of large (up to 0.5 cm3). single-grain R-Mg-Zn quasicrystals (R = Y, Er, Ho, Dy and Tb) from a ternary melt is described in detail. The quasicrystals grown by this technique have a composition R8.7Mg34.6Zn56.8, are thermodynamically stable and have a dodecahedral morphology with clearly visible pentagonal f…
Magnetic anisotropy of La0.7Sr0.3MnO3 thin films and single crystals has been measured using vibrating sample and torque magnetometry. The magnetic anisotropy of thin films is dominated by strain anisotropy due to the lattice mismatch between the film and SrTiO3 substrate. The two and fourfold symmetries in the (110)…
Compounds with the general formula [MM‘(C 3 H 2 O 4 ) 2 (H 2 O) 4 ] (M = Ba, Sr; M‘ = Cu, Mn; C 3 H 2 O 4 = malonate) have been synthesized and characterized. Single-crystal X-ray diffraction study on the [SrCu(C 3 H 2 O 4 ) 2 (H 2 O) 4 ] compound indicates that it crystallizes in the orthorhombic space group, Pccn, Z…