Materials Literature
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A diverse array of semiconductor-based composite materials have been prepared, characterized, and utilized in many applications ranging from photocatalysis, photovoltaic cells, photoelectrochromic displays, and light-emitting devices to sensors. The composite architectures (nanoarchitectures in many cases) are equally…
The electrochemically stimulated conformational relaxation model (ESCR) allows a good description of the chronoamperometric responses of polyaniline in acetonitrile solutions under relaxation control. Compaction, relaxation and diffusion controlled oxidation with penetration of counterions and increase of volume can b…
Kein Tempolimit: PAMAM-Dendrimere der sechsten Generation wurden mit bis zu 198 TEMPO-Gruppen (TEMPO=2,2,6,6-Tetramethylpiperidin-1-oxyl) funktionalisiert (siehe Bild); sie können EPR-inaktive Hydroxylamine zu EPR-aktiven Nitroxiden reoxidieren, was sie interessant für Anwendungen in der EPR-Bildgebung macht.
Polyaniline, (PANI) in the form of emeraldine base, was synthesized by polymerizing aniline in acid solutions at different sub-zero temperatures to give a range of molecular weights between 100,000 and 300,000 gmol<SUP>-1</SUP>. Molecular weights were measured using gel permeation chromatography (GPC). The polymers we…
The mesoscopic morphology of wet-spun polyaniline fibers determines their mechanical strength. Macrovoid formation in the coagulation bath is responsible for poor mechanical properties of these fibers. The effects of polymer concentration, coagulation bath temperature, polymer molecular weight and coagulant on the mor…
The electromechanical actuation performance of carbon nanotube mats, polypyrrole films and hybrid nanotube-polypryrrole materials has been compared. The hybrid materials were formed by coating nanotube mats with polypyrrole using vapour deposition and electropolymerisation techniques. When the coating time was short,…
Hyperbolic Periodic Nodal Surfaces (PNSs) have been investigated with respect to surface modulations. The resulting patterns and tilings are beautiful examples of texture information on hyperbolic objects. The construction principle, based on short Fourier series, allows for a strict symmetry control of the generated…
Spreading a hydrophobic liquid star polymer with ionic head groups and transferring the resulting monomolecular layers to solid substrates with holes provides access to ultrathin, freely suspended elastomeric membranes, which are stable for at least several months.
From magnetic circular dichroism measurements of the Heusler alloy NiMnSb, in combination with other techniques, we show that a dramatic increase in the Mn and Ni moments occurs below a ``crossover'' transition temperature of about 80--100 K. This phase transition is well below the Curie temperature of NiMnSb (\ensure…
Electrical properties of ferroelectric Bi4Ti3O12 (BiT) films on Si(100) using a 1 nm thick silicon oxynitride (SiON) buffer were investigated. The capacitance–voltage (C–V) characteristics of Au/BiT/SiON/Si(100) exhibited hysteresis loops with a memory window of 2 V due to the ferroelectricity, and did not show large…
Des Polymers Kern (wird zum Schluss entfernt): Wasserstoffbrücken-Wechselwirkungen zwischen einem Benzotri(imidazol)-Derivat und einer polymerisierbaren Alkoxybenzoesäure führen zur Bildung supramolekularer hexagonaler columnarer Flüssigkristalle. Durch lichtinduzierte Polymerisation und anschließendes Entfernen des B…
Irradiation of x-rays has induced room-temperature persistent spectral hole burning (PSHB) in Eu3+-doped borate glasses melted under an inert atmosphere. Defects were formed by x-ray irradiation and these defects, especially electron trapping centers near rare-earth ions in glasses, were responsible for the PSHB. Elec…
Abstract Static and dynamic mixers set on the Brabender plastograph were used to investigate the grafting of itaconic acid (IA) onto low‐density polyethylene (LDPE) by the reactive extrusion. The initiators of free‐radical reactions were monoperoxide 2,5‐dimethyl‐2‐hydroxy‐5‐ tert ‐butylperoxy‐3‐hexyne and diperoxide…
Thermal diffusivity (α) of amorphous silicon carbon nitride (a-SiCxNy) thin films on crystalline silicon, prepared by ion beam sputtering, has been studied using the traveling wave technique. The variation of thermal diffusivity with carbon content in amorphous silicon carbon nitride samples are reported. Thermal diff…
Die Addition eines Coliganden bei Reaktionen von Phosphonaten mit Salzen später 3d-Metalle liefert besser lösliche und leichter verarbeitbare Materialien wie den hier gezeigten {Co13}-Käfig (Co: grün, P: violett). Die Struktur enthält zwei zentrale PhPO32−-Liganden, umhüllt von einer sechskernigen Cobalthelix, die wie…
The plane elasticity theory of two-dimensional octagonal quasicrystals is developed in this paper. The plane elasticity problem of quasicrystals is reduced to a single higher-order partial differential equation by introducing a displacement function. As an example, the exact analytic solution of a Mode I Griffith crac…
We report the first observation of the transition between interacting and noninteracting behavior in the ac conductivity spectrum sigma(omega) of a doped semiconductor in its Coulomb glass state near T = 0 K. The transition manifests itself as a crossover from approximately linear frequency dependence below approximat…
Sixth-generation PAMAM dendrimers labeled with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, shown schematically) have been synthesized and are shown to reoxidize EPR-silent hydroxylamines to EPR-active nitroxides. Therefore these dendrimers are potential TEMPO free radical life supporters for EPR imaging.
Low-field intergrain magnetoresistance (IMR) in the polycrystalline materials of double perovskite SrFe0.5Mo0.5O3 is found to be highly tunable by doping either Ca or Ba into the Sr site. The dopant exerts a chemical pressure, changing the Curie temperature and the magnetic softness. The room-temperature IMR at optima…
The results of heat capacity in the presence of an external magnetic field and resistivity measurements on the compounds ${\mathrm{CeCu}}_{x}{\mathrm{Ge}}_{2}$ and ${\mathrm{PrCu}}_{y}{\mathrm{Ge}}_{2}$ with the starting $x=0.86$ and $y=0.76$ are reported. The magnetocaloric effect in the compounds was calculated from…