Materials Literature
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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…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTHyperbranched Poly(ε-caprolactone) Derived from Intrinsically Branched AB2 MacromonomersMikael Trollsås and James L. HedrickView Author Information NSF Center for Polymeric Interfaces and Macromolecular Assemblies (CPIMA), IBM Resea…
We have produced MnZn ferrites via high-energy ball milling (HEBM) of elemental oxides MnO, ZnO, and Fe2O3. X-ray diffraction (XRD) indicates a pure phase spinel forms after 21 h of HEBM. Extended x-ray absorption fine structure (EXAFS) analysis shows a nonequilibrium cation distribution, with an unusually high popula…
Magnesia‐phosphate cement mortars, based on magnesia and ammonium dihydrogen orthophosphate, were prepared with water contents (measured as a weight fraction of the dry material) in the range 5% to 12%. It was shown by XRD that the major reaction product was magnesium ammonium phosphate hexahydrate (MgNH 4 PO 4 6H 2 O…
Using a first-principles approach, we study the vibrational properties of vitreous ${\mathrm{SiO}}_{2}$ which are measured in neutron-scattering experiments. We adopt a model structure consisting of corner-sharing tetrahedra, which was previously generated using first-principles molecular dynamics. We calculate the dy…
Diatom analysis discriminates between the impacts on river water quality of treated urban wastewaters and diffuse nutrient sources from farmland. Evaluation of organic pollution and trophic levels in the Grand River, Ontario, using two diatom indices shows a clear differentiation among 10 sampling sites over a distanc…