Materials Literature
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The magnetic critical behavior in the series ${\mathrm{La}}_{0.67}({\mathrm{Ba}}_{x}{\mathrm{Ca}}_{1\ensuremath{-}x}{)}_{0.33}{\mathrm{MnO}}_{3}$ $(0<~x<~1)$ of manganese perovskites is studied by means of dc magnetic measurements. In this series the ${\mathrm{Mn}}^{4+}{/\mathrm{M}\mathrm{n}}^{3+}$ ratio is kept…
In this paper the pendant drop method to measure interfacial tension between molten polymers is reviewed. A typical pendant drop apparatus is presented. The algorithms used to infer interfacial tension from the geometrical profile of the pendant drop are described in details, in particular a new routine to evaluate co…
The present study describes a novel method of preparing thermosensitive liposomes by compositional modification, incorporating a highly bilayer compatible lysolipid, 1 -Palmitoyl-2-Hydroxy-sn-Glycero-3-Phosphocholine (MPPC) into the gel phase liposomes composed of l,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC). Th…
New hexapyrrolic macrocycles have been synthesized and characterized by UV–VIS, mass and NMR spectroscopy and X-ray crystallography.
The influence of two Ti-precursors, TiO 2 (anatase) and H 2 TiO 3 (β-titanic acid), on the purity and particle size of BaTiO 3 powders prepared via hydrothermal synthesis is discussed. Amorphous H 2 TiO 3 was found to be an excellent Ti-precursor material and offers several advantages over crystalline anatase. Phase p…
Thiophene doping of supported gold catalysts increases the rate of formation of the unsaturated alcohol for the hydrogenation of the α,β-unsaturated aldehyde, crotonaldehyde, providing the first example of the promotion of gold by sulfur.
We have performed photoemission and inverse photoemission experiments on a series of 3d-transition-metal oxides with formal ionic configuration from to . The photoemission core-level spectra are analysed in terms of a simple cluster model leading to estimates for the charge-transfer energy , the Coulomb correlation en…
The viscoelastic behavior of block copolymer melts that exhibit a cubic phase has been examined by oscillatory shear experiments. A low frequency plateau in the measured storage modulus that is absent in the disordered phase is found for both gyroid and body-centered cubic sphere phases of diblock and triblock copolym…
Handbook of Fillers, Fourth Edition, discusses the rapidly advancing field of fillers, the substances added to plastics and composites that add value by improving and modifying the properties of materials and reducing costs. This new edition is an essential reference for engineers and scientists using fillers in a ran…
The use of mixed-oxides containing CeO2 as oxygen storage/release components is discussed with special focus on the applications of these materials in auto-exhaust catalytic converters. Ceria easily forms solid solutions with transition-metal/rare-earth oxides over a wide composition range. The incorporation of dopant…
The influence of the reaction parameters including temperature, oxygen concentration, and of in situ hydrogen reduction on the Pd catalyst activity towards complete methane oxidation is studied experimentally. Zero porosity α-alumina plates are used as a support for Pd catalyst. This lowers the influence of metal–supp…
The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe 2 O 4 , have been investigated by x-ray diffraction, Mössbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe 2 O 4 particles with a partially inverted spinel structure were synthesized by high-energy ball milli…
The solid solutions La 2 Ni 1–x Fe x O 4+δ (x = 0.02 and 0.10), La 1.9 Sr 0.1 Ni 1 – x Fe x O 4 + δ (x = 0.02 and 0.10) and La 2 Ni 0.88 Fe 0.02 Cu 0.10 O 4+δ with the tetragonal K 2 NiF 4 -type structure were prepared by a standard ceramic technique. The thermal expansion coefficients of the ceramic materials, calcul…
The reconstruction of layered double hydroxides with the hydrotalcite-like structure from material previously calcined at increasing temperatures has been studied. Both the calcination temperature and the time the samples spent equilibrating with a controlled water vapour pressure have been considered. The crystallini…
The crystal structures of a large number of silica polytypes ( - and -quartz, - and -cristobalite, -tridymite, keatite, coesite and stishovite) have been studied using density functional theory, both in the local density approximation and including generalized-gradient corrections to the exchange-correlation functiona…
Magnetic and microwave absorbing properties have been investigated in the M-type barium ferrites (BaFe/sub 12-2x/A/sub x/Co/sub x/O/sub 19/) with planar magnetic anisotropy. For the tetravalent A ions, Ti/sup 4+/ and Ru/sup 4+/ are chosen and the samples are prepared by a conventional ceramic processing technique. At…
We present numerical simulations which support the formal asymptotic analysis relating a multiorder parameter Allen--Cahn system to a multiphase interface problem with curvature-dependent evolution of the interfaces and angle conditions at triple junctions. Within the gradient energy of the Allen--Cahn system, the nor…
Beside normal cyclization/ring-opening photochromic reactions, a side reaction to produce a photostable by-product took place when 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene was irradiated in deaerated hexane with ultraviolet light.
Amorphous silver nanoparticles of ca. 20 nm size have been prepared by the sonochemical reduction of an aqueous silver nitrate solution in an atmosphere of argon-hydrogen. The silver nanoparticles have been characterized by TEM, X-ray diffraction, absorption spectroscopy, differential scanning calorimetry and EPR spec…
Polarized neutron scattering has been used to determine the changes in the distribution of unpaired electrons which take place in the martensitic transition in Ni 2 MnGa. Ni 2 MnGa is a ferromagnetic Heusler alloy which undergoes a reversible transition at about 220 K from a high temperature cubic phase to a low tempe…