Materials Literature
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Recent research into the development of magnetic refrigeration (MR) operating at room temperature has shown that it can provide a reliable, energy-efficient cooling system. To enhance the cooling power of the magnetic refrigerator, it is required to use a magnetic refrigerant material with large magnetocaloric effect…
The substitution at the Mn site of various transitional metal elements dramatically modifies the magnetic and electronic properties of the La0.7Pb0.3Mn0.8Me0.2O3 (Me=Ni, Co, and Fe) manganites. The powder x-ray diffraction pattern shows a single-phase rhombohedral distorted perovskite structure with space group R3̄c (…
Microstructures of bamboo-like multiwalled carbon nanotubes prepared by pyrolysis of Ni-phthalocyanine are studied by high-resolution transmission electron microscopy. The intershell spacings of graphitic shells in these nanotubes are estimated. From pristine nanotubes with a tube diameter of 40–260 nm, the spacing va…
The hydrodynamic coarsening of microphase separation in two-dimensional diblock copolymers is studied using numerical simulations. Results for symmetric and asymmetric block copolymers are compared. In contrast to the formation of the hexagonal phase where hydrodynamic flow appears not to be effective in enhancing dom…
Mixed sodium–rubidium borate glasses with compositions 0.2[XNa2O·(1-X)Rb2O]·0.8B2O3 (X = 1.0; 0.8; 0.6; 0.4; 0.2; 0.0) were prepared from alkali-metal carbonates and diboron trioxide. The density ρ and the molar volume Vmol of the prepared glasses vary almost linearly with composition whereas the glass-transition temp…
Using x-ray submicrobeam, we spatially mapped the strain in epitaxial La1−xSrxMnO3 films grown on SrTiO3(001) bicrystal substrates. Our results show that there is an elastic strain gradient at the artificial grain boundary, which decays over a length scale of ∼1 μm. The tensile strain at the interior of the grain—due…
The poly[(R)-3-hydroxyalkanoate] (PHA) synthase gene (phaC(Ac)) of Aeromonas caviae FA440 was modified by adding a peroxisome targeting signal encoding the last 10 amino acids at the carboxyl-terminal of spinach glycolate oxidase. The modified gene was introduced into Arabidopsis thaliana plants by Agrobacterium-media…
A method for the analysis of temperature and field dependent magnetization data near the Curie temperature TC is devised, which allows the reliable determination of critical exponents even in strongly inhomogeneous ferromagnets. It is shown, both experimentally and theoretically, that the field-induced broadening of t…
We focus on the dynamical properties of dendrimers and of randomly built branched polymers, which allows us to assess theoretically the role of disorder on the relaxation forms. We model the random polymers through a stochastic growth algorithm. Our studies are carried out both in the Rouse and also in the Zimm framew…
The compounds (Sr2−xCax)FeReO6 (x=0, 0.2, 0.5, 1.0, 1.5, and 2.0) were synthesized by solid state reaction. The resistivity exhibits a metallic behavior for Sr2FeReO6 and insulating behavior for Ca2FeReO6. Structural transformation is observed from tetragonal (x⩽1) to monoclinic (x⩾1.5). The Curie temperature increase…
ADVERTISEMENT RETURN TO ISSUEPREVNoteFormation of BaSO4 Nanoparticles in Microemulsions with Polymerized Surfactant ShellsMark Summers, Julian Eastoe, and Sean DavisView Author Information School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom Cite this: Langmuir 2002, 18, 12, 5023–5026Publication…
Three undoped lead zirconate titanate (PZT) ceramics were prepared with compositions close to the morphotropic phase boundary: Pb(Zr0.50Ti0.50)O3, Pb(Zr0.52Ti0.48)O3, and Pb(Zr0.54Ti0.46)O3. Internal friction Q−1 and shear modulus G were measured versus temperature from 20 °C to 500 °C. Experiments were performed on a…
Blending a liquid crystalline polymer (LCP) with an amorphous polymer to create a molecular composite offers a method to utilize the desirable properties of a LCP at a more modest cost. However, very few such blends are miscible. In this paper, we describe the results of a study that seeks to correlate the extent of i…
Polymer embedded granular composites, La2/3Ca1/3MnO3/polyparaphenylene (LCMO)1−x(PPP)x (x is the weight fraction of PPP), were prepared and their magnetoresistance (MR) properties were investigated. A significant enhancement in MR is observed for the composites especially in the low temperature range. The MR reaches t…
The Y 2 O 3 :Eu phosphor particles having a spherical shape and dense morphology were prepared by a pilot-scale spray pyrolysis process which involved the introduction of polymeric precursors in the spray solution. The Y 2 O 3 :Eu particles prepared from the solution without polymeric precursors had a hollow and fract…
Fluorine-doped lanthanum molybdates with the nominal formula La 2 Mo 2 O 9 - 0.5 x F x ( x = 0.20−0.30) were synthesized and characterized using powder X-ray diffraction, electron diffraction, differential thermal analysis, and impedance spectroscopy. Comparisons are made with the parent anionic conductor system La 2…
Cobalt-substituted SBA-1 cubic mesoporous molecular sieves have been synthesized in the presence of the cationic surfactant cetyltriethylammonium bromide. UV−vis spectra revealed that the majority of the cobalt ions in the CoSBA-1 samples are present in a highly dispersed state and occupy framework position (Co(II) is…
Silver telluride nanowire arrays were synthesized by cathodic electrolysis into porous anodic alumina membranes from dimethyl sulfoxide (DMSO) solutions containing 0.1 M NaNO3, 5.0 mM AgNO3 and 6.0 mM TeCl4. XRD and SAED patterns of the nanowires were indexed to be a monoclinic structure of Ag2Te. TEM images show that…
The dielectric relaxation of water molecules in polymer–water mixtures is discussed. The memory function approach and scaling relationships are used as a basis for the model of symmetric dielectric spectrum broadening. The correspondence between the relaxation time, the geometrical properties, the self-diffusion coeff…
Recently, reverse micelles were used to produce core/shell nanoparticles of iron and gold of highly uniform size distribution and reported to contain metallic iron. A composite structure of this sort is attractive in biosensor and bioactuator applications; the metallic iron core provides high magnetic sensitivity and…