Materials Literature
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A crosslinkable metallocene polyethylene–octene elastomer (POE) containing different amounts of dicumyl peroxide (DCP) was prepared in a mixer at 110°C to remove the methanol and to ensure a uniform distribution of DCP. A crosslinking reaction of the crosslinkable mixture was carried out for 20 min in a hot press at 1…
BaFe 12 O 19 films have been grown by pulsed laser deposition (PLD) on (001) sapphire using two different conditions (with and without oxygen). Layers grown in O2 atmosphere exhibit an epitaxial structure (stressed at the interface) with a perpendicular easy axis whereas magnetic anisotropy is randomly oriented in tho…
Rice husk powder (RHP) and silica-filled polystyrene (PS)/styrene butadiene rubber (SBR) composites were prepared by using the laboratory size internal mixer (Brabender Plasti-corder). The torque development, morphology, and mechanical properties such as tensile strength, elongation at break, Young modulus, and impact…
Effective medium theory was used to model optical properties in the 0.3 – 30 μm wavelength range for films comprised of nanoparticles of a transparent conducting oxide that are connected in a percolating network characterized by a filling factor f. The model is based on charge carrier density ne and resistivity ρ of t…
We have investigated the molecular orientation in the films of polyamic acid (PAA) with azobenzene units in the backbone structure. Anisotropic molecular orientation was induced by irradiation of linearly polarized ultraviolet light (LPUVL). The change in the molecular orientation caused by subsequent thermal imidizat…
Highly ordered macroporous titania films (see Figure) can be prepared over large areas using colloidal silica spheres as a template. This template material has a number of advantages over the more commonly used polystyrene spheres, such as easy removal of the template by immersion in a warm NaOH solution and shrinkage…
Ein Satz neuer Reifen: Die Substitution eines Chrom-Ions im Komplex [Cr8F8(O2CCMe3)16] durch andere Übergangsmetalle führte zu Heterometall-„Rad“-Komplexen (siehe Bild), die in ihren Zentren durch sekundäre Ammoniumionen gestützt werden. Sowohl 3d- (Mn, Fe, Co, Ni) als auch 4d-Metalle (Cd) wurden zur Herstellung derar…
Neutral alkyl-substituted spirobiphenalenyl radicals (see formula) were recently reported that exhibit bistability as a consequence of temperature-dependent hysteretic switching. The high- and low-temperature forms display significant differences in their electrical, optical, and magnetic properties.
Lightweight magnetic ceramics containing bimetallic (Co–Fe) nanoparticles in an essentially amorphous C/SiC matrix have been prepared from the pyrolysis of a polyferrocenylsilane with pendant cobalt clusters. The Figure shows a TEM image of the ceramic material formed at 600 °C under N 2 . Superparamagnetic or ferroma…
Individual Mn 12 single‐molecule magnets are arranged onto a polymeric film surface using a new, soft, reliable and simple chemical methodology. Polymeric thin films, prepared from a polycarbonate matrix and Mn 12 molecules, are subsequently treated with an organic solvent vapor, resulting in nanocomposite thin films…
Germanium‐filled SiO 2 nanotubes and aligned SiO 2 nanofibers are synthesized via a two‐stage process: thermal evaporation of SiO powder, followed by laser ablation of a Ge target. The nanotubes are either partially filled with Ge nanoparticles/nanorods or completely filled with Ge nanowires, forming Ge/SiO2 nanocable…
Fluoride is a naturally occurring element in many water supplies, and it may cause fluorosis. The hydrotalcite was synthesized and characterized before and after the retention of fluoride ions by x-ray diffraction, electron microscopy, and IR. The thermally treated hydrotalcite was evaluated for the sorption of fluori…
Teilstrukturen in Form einer verdrehten Acht weisen die perfluorierten meso-Aryl-substituierten expandierten Porphyrine auf, die man aus 3,4-Difluorpyrrol und Pentafluorbenzaldehyd unter modifizierten Rothemund-Lindsey-Bedingungen erhält. Das [26]Hexaphyrin enthält zwei nahezu planare Tripyrrol-Untereinheiten, die um…
Copper and silver films are being considered for future multilevel interconnect systems. The reduction of feature size has also demanded the use of different low-dielectric materials (e.g., parylenes) in place of conventional silicon dioxide based layers. Adhesion of these materials with each other is a major hurdle i…
A technique has been developed for the measurement of the K22 twist elastic constant in nematic liquid crystal materials. This involves the measurement of the Freedericksz transition voltages in untwisted linear and π-twist regions in a wedge cell geometry. The method avoids the need for the accurate determination of…
Far-infrared reflectivity spectra of [Pb(Zn1/3Nb2/3)O3]0.92–[PbTiO3]0.08 and [Pb(Mg1/3Nb2/3)O3]0.71–[PbTiO3]0.29 single crystals were investigated between 10 and 530 K, micro-Raman spectra were recorded between 300 and 800 K. No phonon softening was observed near either of the ferroelectric phase transitions. The low-…
A vanadium-substituted polyoxomolybdate ion ([PV2Mo10O40]5−, top right) can activate nitrous oxide to promote the highly selective catalytic oxidation of primary and secondary alcohols to aldehydes and ketones, and the oxidation of various alkylaromatic substrates (see scheme).
The need to develop powerful new catalysts capable of effecting reductions with molecular hydrogen under mild conditions is a pressing one, particularly with the looming importance of the hydrogen economy. We show that nanoparticle (1−1.5-nm diameter) supported bimetallic catalysts, such as Ru−Pd, Ru−Pt, and Ru−Sn, pr…
We propose a new solidification process in crystallizable polymers in which lamellar clustering takes place in the crystallization process under high supercoolings. Clustering of lamellae is a two-step process: the first step is the exclusion process of chain ends from the space of a single Gaussian chain accompanied…
The dc and ac conductivities of Mn-doped ZnO were investigated at temperatures from 10 to 100 K. The temperature dependence of the dc conductivity from 10 to 100 K shows an abrupt change at ∼18 K, manifesting a much lower activation energy for conduction below 18 K. From 10 to 18 K, the ac conductivity, σac(ω), varies…