Materials Literature
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The high-temperature characteristics of donor-doped SrTiO 3 /indium tin oxide (ITO) Schottky solar cells were investigated by current–voltage and impedance analyses at various oxygen partial pressures ( P O 2 ) (1–10 -4 bar) at 873 K. Both current–voltage and impedance characteristics showed a reversible oxygen partia…
The ferrimagnetic compounds Ca(Cu x Mn 3− x )Mn 4 O 12 of the double distorted perovskites AC 3 B 4 O 12 family exhibit a rapid increase of the ferromagnetic component in magnetization at partial substitution of square coordinated (Mn 3+ ) C for (Cu 2+ ) C . In the transport properties, this is seen as a change of the…
The grain microstructure evolution in the course of two dimensional (2D) grain growth is considered in greater detail, taking into account the influence of grain boundary triple junctions. It is shown that there are two limiting regimes of grain growth in polycrystals: the first one is associated with the situation wh…
The photoelectric properties of TlGa 1− x Yb x S 2 ( x = 0, 0.01) single crystals are investigated. It is established that partial substitution of ytterbium for gallium leads to (i) an increase in the electrical resistivity of the samples, (ii) a shift in the maximum of the intrinsic photocurrent toward the long-wavel…
Dielectric properties of the relaxor films are theoretically investigated with the Monte Carlo simulation. We find that the size effect on the dielectric susceptibility of films is neglectable while the influence of the surface layer of the film is overlooked. On the contrary, while the surface layer is explicitly con…
Recent studies involving porphyrin systems bearing fused five-membered rings are reviewed, these including pyrrolo[3,4-b]porphyrins and fused metallocenoporphyrins. Diels-Alder cycloadditions between pyrroloporphyrins, to give benzoporphyrins, are discussed. The syntheses of mono-, and the two regioisomers (adj- and o…
A novel electrically conductive photoresist has been formulated to fabricate microcomponents. The developed conductive photoresist is based upon SU-8 photopolymer, an insulating negative-tone epoxy, in which protonically doped polyaniline (PANI) nanoparticles have been dispersed to enhance the electrical properties. T…
In Gd1−x SrxMnO3 (x = 0.5, 0.6, 0.7) single crystals, a change in electric polarization (ΔP ∼ 100 μK/m2) is found to accompany the suppression of the charge-ordered spin-glass state and the transition to the ferromagnetic conducting phase (H cr ∼ 100 kOe at 4.5 K). The transition is also characterized by jumps in magn…
Os polietilenos lineares de baixa densidade (PELBD) são uma classe de polietilenos com cadeias lineares contendo somente ramificações de cadeia curta devido à inserção de uma alfa-olefina durante as reações de copolimerização com o eteno. As alfa-olefinas comumente utilizadas são o 1-buteno, o 1-hexeno e o 1-octeno. D…
Abstract The effect of a large amount of precipitated amorphous white silica nanofiller, pre-treated with bis[3-triethoxysilylpropyl-)tetrasulfide (TESPT), on the mechanical properties of a sulfur-cured natural rubber (NR) was studied. TESPT chemically adheres silica to rubber and also prevents silica from interfering…
Neste trabalho foi feito um estudo de tendências tecnológicas em nanotecnologia aplicado ao setor de materiais poliméricos, com base em informações extraídas de documentos de patentes. Foi usada como fonte de dados o banco de patentes da USPTO (United States Patent Trademark Office). Os dados foram obtidos via web, ut…
A series of 50:50 polycarbonate‐poly(ethylene terephthalate) (PC‐PET) blends were formed via reactive melt blending in a torque rheometer at 270°C. The degree of interfacial transesterification between the two homopolymers was promoted by the incorporation of an alkyl titanium catalyst during melt blending. The result…
Advancements in both the design and construction of high-speed naval vessels have necessitated the evaluation of the building materials in a cavitating environment. Given their weight advantages, construction materials are often either aluminum or glass reinforced polymer (GRP) composites. Historically, neither of the…
The strength of partially stabilized zirconia-based ceramics is analyzed as a function of the porosity, the grain size, and the degree of tetragonality of the tetragonal phase. It is found that the strength of the studied ceramics, unlike conventional materials, is virtually independent of the porosity and the average…
Abstract Aqueous poly(urethane‐urea) dispersions were prepared by the prepolymer mixing technique, without using any organic solvent. This work focused on the incorporation into the prepolymer chain of specific macrodiols bearing acrylic, polycarbonate and perfluoro‐oligoether chains, in conjunction with a poly(propyl…
The synthesis and characterization of novel ionic liquid crystals displaying columnar mesomorphism induced upon complexation of 2,2′-bipyridine-4,4′-disubstituted ligands ( L n ) are reported. A tetracoordination around the silver( I ) centre has been obtained for the first time in metallomesogens based on chelated bi…
The development of ultrafine grained microstructures in steels has received considerable attention in recent times. In many cases the aim is to produce high strength structural steels with minimal alloying. It is well established that for an equiaxed ferrite with a uniform dispersion of second phase, both the strength…
The present paper reports the application of a five parameter determination of grain boundary types to grain boundary engineered α brass. Approximately 20 000 grains constituted the total sample population, giving rise to more than 77 000 grain boundary line segments. This is the first time that the orientation of a l…
In the years 1997 and 1998, the diatom flora of Lake Neure, Iran was studied from June through September. The lake, located at 2480 m elevation, had an electrical conductivity between 187–320 μS/cm in 1997 and between 143–259 μS/cm in 1998. During 1997 the pH was lower than in 1998 but in both years the pH was above 8…
Two series of ortho‐metallated palladium imine complexes are reported that contain a coordinated β‐diketonate group. In one group the chain length of the imine is varied while the β‐diketone is unchanged; in the other the imine chains are both fixed as methoxy and the structure of the β‐diketonate is varied. The mesom…