Materials Literature
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Abstract A new ether‐bridged aromatic dicarboxylic acid, 2′,5′‐bis(4‐carboxyphenoxy)‐ p ‐terphenyl ( 3 ), was synthesized by the aromatic fluoro‐displacement reaction of p ‐fluorobenzonitrile with 2′,5′‐dihydroxy‐ p ‐terphenyl in the presence of potassium carbonate, followed by alkaline hydrolysis. A set of new aromat…
Abstract Dithienylperfluorocyclopentene derivatives that bear alkyl substituents connected onto the two carbon atoms of the thiophene heterocycles where, in their ring-closed form, the new C–C single bond is formed (the 2-positions of the thiophene), can exhibit photochromic ring-closing, and both photochromic and ele…
The synthesis, isolation, and single-crystal X-ray structures of the first polyhedral ferrous and ferric siloxanes (see scheme) suggest that similar synthetic strategies will allow the preparation of other transition-metal siloxane frameworks.
We have investigated the low-temperature phase of a ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$ single crystal by x-ray resonant scattering at the $\mathrm{Mn}$ $K$ edge of the $(3 0 0)$, $(0 3 0)$, and $(0 5∕2 0)$ reflections. Strong resonances were observed for the $\ensuremath{\sigma}--{\ensuremath{\…
It has long been controversial as to whether small volumes of material are, or should be, more resistant to plastic deformation than is implied by the yield strength of bulk material. We generalize the established theory of critical thickness for strained layers to show that there is an increase in the initial yield s…
The velocity fluctuations present in macroscopically homogeneous suspensions of neutrally buoyant non-Brownian spheres undergoing simple shear flow, and their dependence on the microstructure developed by the suspensions, are investigated in the limit of vanishingly small Reynolds numbers using Stokesian dynamics simu…
Kohlenstoffkugeln sind die Template für die Synthese von Halbleiterhohlkugeln aus Ga2O3 (abgebildet) und GaN. Dicke und Einheitlichkeit der Endprodukte werden durch die Dicke der aktiven Schicht der Kohlenstoffkugeln festgelegt. Der Kugeldurchmesser kann auf Werte zwischen 100 nm und 1.5 μm eingestellt werden, womit B…
Salt-assisted sphere-to-cylinder micelle conversion in the microemulsion polymerization process is the crucial step for the formation of polyacrylonitrile nanofibers (see picture). Iron(III) chloride is used as a structure-directing agent and is coordinated by polyacrylonitrile nanoparticles, which is essential for th…
For several decades the propagation characteristics of acoustic pulses (attenuation and sound speed) have been inverted in attempts to measure the size distributions of gas bubbles in liquids. While this has biomedical and industrial applications, most notably it has been attempted in the ocean for defence and environ…
We have performed a comparative study of rubrene single-crystal field-effect transistors fabricated using different materials as gate insulator. For all materials, highly reproducible device characteristics are obtained. The achieved reproducibility permits to observe that the mobility of the charge carriers systemati…
We have studied the coherent dynamics of injected electrons when they are either free or bounded both in excitons and in trions (charged excitons). We have considered a remotely doped asymmetric double quantum well where an excess of free electrons and the direct created excitons generate trions. We have used the matr…
We report a new theoretical method for X-ray absorption spectroscopy (XAS) in condensed matter which is based on the multi-channel multiple scattering theory of Natoli et al. and the eigen-channel R-matrix method. While the highly flexible real-space multiple scattering (RSMS) method guarantees a precise description o…
We have developed a wedge-loaded double-cantilever beam adhesion measurement set-up for thin films deposited on glass by sputtering. The test is described in details. Results on the Glass/sublayer/Ag/ZnO multilayer provide evidence that \SnOd or \TiOd perform better than ZnO as a sublayer. Then however, rupture within…
Finite magnesium oxide nanotubes are investigated. Stacks of four parallel squares, hexagons, octagons, and decagons are constructed and studied by the pseudopotential density functional theory within the local-density approximation. Optimized structures are slightly distorted stacks of polygons. These clusters are in…
First-principles density-functional theory and supercell models are employed to calculate the adsorption of water molecules on the Cu(100) surface. In agreement with the experimental observations, the calculations show that a H2O molecule prefers to bond at a one-fold on-top (T1) surface site with a tilted geometry. A…
Carbon materials are attracting increasing attention due to the novelty of the associated physical properties and the potential applications in high-tech devices. The possibility to achieve outstanding properties in macroscopic carbon materials opens up a profusion of new striking applications. Magnetic properties ind…
A recent exciting experiment by Ghosh et al. reported that the flow of an ion-containing liquid such as water through bundles of single-walled carbon nanotubes induces a voltage in the nanotubes that grows logarithmically with the flow velocity v0. We propose an explanation for this observation. Assuming that the liqu…
Carbon spheres are used as templates to prepare semiconductor hollow spheres of Ga2O3 (depicted) and GaN. The thickness and uniformity of the final products are predetermined by the thickness of the active layer of the carbon spheres. The diameter of the spheres can be adjusted in the range of 100 nm to 1.5 μm, which…
X-ray reflectivity measurements of the binary liquid Ga-Bi alloy reveal a dramatically different surface structure above and below the monotectic temperature $T_{mono}=222^{\circ}$ C. A Gibbs-adsorbed Bi monolayer resides at the surface at both regimes. However, a 30 Å thick, Bi-rich wetting film intrudes between the…
EPR and FT-IR spectroscopy have been used to investigate the B 2 O 3 – Bi 2 O 3 glass matrix containing CuO in order to obtain more information about the local structure of these glasses. The EPR absorption spectra revealed the presence in the glass structure of the Cu 2+ ions in axially distorted octahedral environme…