Materials Literature
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We analyze structural and conformational properties in a simulated bead-spring model of a nonentangled, supercooled polymer melt. We explore the statics of the model via various structure factors, involving not only the monomers, but also the center of mass (CM). We find that the conformation of the chains and the CM-…
The dynamics of ferroelectromagnetic (multiferroic) crystals RMn 2 O 5 (R = Eu and Gd), showing magnetic and ferroelectric phase transitions with close transition temperatures (40 and 30 K for R = Eu and Gd, respectively), was studied in the frequency and temperature ranges 20–300 GHz and 5–50 K, respectively. It was…
To study the effects of disulfide bonds on certain functional properties of films made from the wheat gluten proteins gliadin and glutenin, cysteine was used to promote the formation of interchain disulfide bridges between gliadins in 70% ethanolic solution. Disulfide-mediated polymerization of gliadins was confirmed…
Good quality CaCu 3 Ti 4 O 12 giant dielectric constant films have been prepared by metal–organic chemical vapor deposition on LaAlO 3 (001) substrates, using a multimetal molten precursor source. The growth of the oxide layer by a two‐step in‐situ process, namely deposition of an amorphous matrix and the consequent i…
Solid solutions of $(1\ensuremath{-}x)\mathrm{Pb}({\mathrm{Sc}}_{2/3}{\mathrm{W}}_{1/3}){\mathrm{O}}_{3}--(x){\mathrm{PbTiO}}_{3}$ and $(1\ensuremath{-}x)\mathrm{Pb}({\mathrm{Sc}}_{2/3}{\mathrm{W}}_{1/3}){\mathrm{O}}_{3}--(x){\mathrm{PbZrO}}_{3}$ (PSW-PT and PSW-PZ) show remarkably different dielectric responses. Even…
Fluorescence is reversibly photoregulated in high‐density random copolymers constructed from photochromic phenoxynaphthacenequinones and porphyrins (see Figure) using ring‐opening metathesis polymerization. Alternating irradiation of the polymers with ultraviolet and visible light toggles the photochromic components b…
Boron inserted as impurity by substitution of carbon atoms in graphite is known to modify the reactivity of the surface in interaction with hydrogen. Boron induces a better H retention capability in graphite while it makes easier the recombination into molecular hydrogen under heating in thermal-desorption experimenta…
By employing computer simulations for a model binary mixture, we show that a reentrant glass transition upon adding a second component occurs only if the ratio alpha of the short-time mobilities between the glass-forming component and the additive is sufficiently small. For alpha approximately 1, there is no reentrant…
In marine mussels (Mytilus), byssal threads are made in minutes from prefabricated smectic polymer liquid crystals by a process resembling reaction injection molding. The mesogens in these arrays are known to be natural block copolymers with rodlike collagen cores. Using atomic force microscopy, it was shown that thes…
Continuous mesoporous carbon thin films (see Figure) have been synthesized through direct carbonization of sucrose/silica nanocomposite films and subsequent removal of the silica to create a mesoporous carbon network. This method provides a simple and efficient method to synthesize continuous, high surface area and po…
We present a detailed study on the impact of multimode transport in carbon nanotube field-effect transistors. Under certain field conditions electrical characteristics of tube devices are a result of the contributions of more than one one-dimensional subband. Through potassium doping of the nanotube the impact of the…
Coaxial cubic‐aluminum‐nitride–boron‐nitride composite nanotubes have been synthesized via a template‐free and catalyst‐free two‐stage route. The synthesized nanotubes have a uniform outer diameter of 50 nm and wall thickness of 15 nm, with a 2–3 nm thick BN coating. A vapor–solid (VS) mechanism is proposed for their…
Linksgängig helicale Nanoseile entstehen beim Gelieren eines starren π-konjugierten Oligo(p-phenylenvinylens) mit entfernten chiralen Hanteln (siehe Bild; R=C12H25) aus Ensembles höherer Ordnung von chiralen Aggregaten. Die konzentrations- und temperaturabhängigen Änderungen der CD-Signale dieser Ensembles sind charak…
The use of time-dependent density functional calculations for the optimization of excited-state structures and the subsequent calculation of resonance Raman intensities within the transform-theory framework is compared to calculations of Hartree-Fock/configuration interaction singles-type (CIS). The transform theory o…
The iron( II ) complex [Fe(3C16‐L) 2 (NCS) 2 ] (see Figure) exhibits three coexisting physical properties due to its geometric flexibility. It shows liquid‐crystal behavior in the temperature range 345–400 K, spin‐crossover behavior ( T 1/2 = 217 K) between high‐spin and low‐spin states, and photoinduced spin transiti…
Highly organized monolayer and multilayer films of titania nanosheets have been fabricated via electrostatic self‐assembly of large‐sized sheets and subsequent ultrasonic treatment. Overlapped or crumpled portions of the nanosheets in an as‐deposited film are effectively trimmed upon ultrasonication in a tetrabutylamm…
Combining optical control theory with ab initio quantum chemistry and electronic crystal field theory we explore the laser induced femtosecond spin dynamics. We propose a scenario for ultrafast all-optical magnetic switching that results from the combination of spin-orbit coupling with appropriately shaped short laser…
Polycyclic aromatic hydrocarbons (PAHs) are employed to model the Raman features that are generally associated with sp(2) nanostructures in carbon materials or with disorder and defects in graphitic materials. To this end molecular parameters (geometry changes upon electronic excitation, vibrational normal modes, and…
A soft‐template method for the controlled synthesis of hollow beads using laser‐ assisted growth with ethanol droplets as the soft template is proposed (see Figure). Single‐crystalline ZnO polyhedral hollow beads in the range of 200–500 nm have been successfully synthesized.
Ultrafine magnetic nickel ferrite NiFe2O4 particles of high crystallinity were directly prepared by forced hydrolysis of ionic iron (III) and nickel (II) solutions in 2-hydroxyethyl ether at about 478 K under atmospheric pressure. The resulting nickel ferrite particles exhibit very interesting magnetic properties: the…