Materials Literature
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Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give place to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction which represents a promising field regarding to short-term tech…
Thin films were grown on amine-primed Si and glass substrates by sequential adsorption reactions of polyallylamine hydrochloride (PAH) and anionic colloids derived from HTiNbO 5 and HCa 2 Nb 3 O 10 . The acid−base chemistry of polycation/polyanion adsorption was studied in detail for PAH/HTiNbO 5 . The p K a of PAH, d…
We obtain an analytical solution of a one-dimensional sandpile problem in a thick flow regime, when it can be formulated in terms of linear equations. It is shown that a space periodicity takes place during the sandpile evolution even for a sandpile of only one type of particles. Similar periodicity was observed previ…
We examined what determines the designability of 2-letter codes (H and P) lattice proteins from three points of view. First, whether the native structure is searched within all possible structures or within maximally compact structures. Second, whether the structure of the used lattice is bipartite or not. Third, the…
2,2-Dibutyl-2-stanna-1,3-dioxepane (DSDOP) was polycondensed at 80 °C in bulk with succinyl chloride, adipoyl chloride, suberoyl chloride, sebacoyl chloride, and 1,12-dodecanedioyl chloride. In the case of adipoyl chloride the stoichiometry was varied and the temperature in the case of sebacoyl chloride. With a slight…
A unified interpretation is presented for high-temperature (ca. 423 K) unit-cell enlargement of MCM-41 synthesized in the presence of cetyltrimethylammonium (CTMA + ) surfactants without auxiliary organics. Such processes during postsynthesis hydrothermal treatments and direct syntheses were reported by several resear…
The decay of a crystalline cone below the roughening transition is studied. We consider local mass transport through surface diffusion, focusing on the two cases of diffusion limited and attachment-detachment limited step kinetics. In both cases, we describe the decay kinetics in terms of step flow models. Numerical s…
The dynamics of an individual magnetic moment is studied through the Landau-Lifshitz equation with a periodic driving in the direction perpendicular to the applied field. For fields lower than the anisotropy field and small values of the perturbation amplitude we have observed the magnetic moment bistability. At inter…
A tight binding parameterization of the band structure, along with a mean field treatment of Hund, electron-electron, and electron-lattice couplings, is used to obtain the full optical conductivity tensor of LaMnO_3 as a function of temperature. We predict striking changes with temperature in the functional form and m…
<div class="htmlview paragraph">Many efforts have been made to apply the diesel exhaust particulate after-treatment system in practical use during the past ten years. In this paper, a diesel exhaust particulate after-treatment system with microwave energy as its external regeneration energy source is described,…
Neue Gerüstmaterialien, die aus wohldefinierten Vanadiumoxidclustern bestehen, wurden durch Niedertemperatursynthesen hergestellt und röntgenographisch charakterisiert. In den Strukturen dieser Feststoffe sind {V18O42}-Käfige vorhanden, die über {M(H2O)4}-Brücken (M = FeII, CoII) zu zwei sich gegenseitig durchdringend…
The thermal stability of nonstoichiometric carbon nitride films has been studied by x-ray absorption near edge spectroscopy. Amorphous carbon nitride thin films were annealed in vacuum up to 1150 °C revealing the presence of nitrogen in different bonding configurations. Annealing to 450 °C results in the loss of ∼50%…
By the synthesis of new titanosilsesquioxanes, which incorporate both alkoxides and BINOL, significant correlations have been found between the nature of the ligands bound to the TiIV centers and the ablility of the complexes to act as catalysts active in the epoxidation of alkenes (see diagram).
An unprecedented nonplanar structure characterizes the complex [Fe(OCH3)2(dbm)]12 (on the left in the picture), which contains the largest cyclic ferric cluster yet reported with chemically equivalent bridging units. It is made up of twelve high-spin, antiferromagnetically coupled iron(III) centers and neatly reacts w…
Titanium alloys are commonly heat-treated to meet specific design requirements. In an effort to possibly create a better composite, the influence of heat treatments on the damage evolution and strength of a SiC/Ti-15-3 metal matrix composite (MMC) was studied. Heat treatments of 450°C and 700°C for 24 hours were perfo…
Local antiferroelectric order of lattice distortion caused by an ionic size difference has been discovered in relaxor lead scandium niobate, $\mathrm{Pb}(\mathrm{Sc}{}_{1/2}\mathrm{Nb}{}_{1/2})\mathrm{O}{}_{3}$, using an x-ray diffuse scattering technique. This ordering nature is thought to produce a glassy motion of…
More than 10 000 carboxylic acid groups are covalently coated on monodisperse silica nanoparticles (see schematic diagram) prepared by a Stöber synthesis. Colloidal super crystals form spontaneously on dissociation in aqueous dispersion with low ionic strength.
Secondary hydrogen-bonding interactions have been exploited to construct layered magnetic solids based on amidinium–carboxylate salt bridges. The salt bridge is utilized as a supramolecular synthon to set the structural organization in a layered motif; it also serves as a spin communication element. The magnetic mater…
In this work, we add a small amount of a guest–host dye G-206 in the polymer-dispersed liquid crystal mixtures to fabricate holographic gratings. Following formation, the grating is irradiated by a single Ar+ laser beam while probed by a He–Ne laser. Experimental results indicate that the first-order diffracted intens…
We report a technique which allows self-assembly of conducting nanoparticles into long continuous chains. Transport properties of such chains have been studied at low temperatures. At low bias voltages, the charges are pinned and the chain resistance is exponentially high. Above a certain threshold VT, the system ente…