Materials Literature
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Magnetic ordering around the ferroelectric transition temperature T C1 of weakly ferroelectric YMn 2 O 5 has been reinvestigated by single-crystal neutron diffraction and dielectric measurements. Besides a two-dimensionally modulated incommensurate magnetic (2D-ICM) phase with the propagation vector q = ( q x ,0, q z…
Abstract The temperature dependence of the vibrational modes of lead barium niobate (Pb x Ba 1– x Nb 2 O 6 ), which belongs to the tungsten‐bronze family of oxygen octahedra ferroelectrics, were investigated for the first time using the Raman scattering technique. The investigated sample ( x = 0.60) exhibits a ferro–p…
Spin-Crossover in Gelen: Thermoreversible, schaltbare Gele mit einstellbaren magnetischen, optischen und rheologischen Eigenschaften werden aus einer modifizierten polymeren Spin-Crossover-Vorstufe und Alkansolventien erhalten (siehe Bild). Das als Gelator fungierende Eisentriazolpolymer geht einen Spin-Crossover ein,…
We describe a broadband achromatic half-wave retarder for normally incident light of arbitrary polarization. The device consists of a stack of one nematic liquid-crystal cell with uniform alignment sandwiched between two twisted nematic layers that have identical twist angles (135 degrees) but different orientations o…
The kinetics of vaterite (CaCO 3 ) crystallization on calcite in the presence of aspartic acid was investigated by the constant composition technique. The presence of aspartic acid in the supersaturated solution stabilizes this calcium carbonated polymorph possibly through the development of active growth sites, which…
The longitudinal acoustic (LA) mode of bulk ${\mathrm{Ge}}_{x}{\mathrm{Se}}_{1\ensuremath{-}x}$ glasses is examined in Brillouin scattering (BS) over the $0.15<x<1/3$ range using near band-gap radiation ($\ensuremath{\lambda}=647.1\text{ }\mathrm{nm}$). The LA-mode frequency (${\ensuremath{\nu}}_{\mathrm{LA}}$)…
Phosphate is an essential nutrient that must be taken up from the growth medium through specific transporters. In Saccharomyces cerevisiae, both high and low affinity orthophosphate carriers allow this micro-organism to cope with environmental variations. Intriguingly, in this study we found a tight correlation betwee…
The structural and dynamic properties of dioctadecyldimethylammoniums (DODDMA) intercalated into 2:1 layered clays are investigated using isothermal−isobaric (NPT) molecular dynamics (MD) simulation. The simulated results are in reasonably good agreement with the available experimental measurements, such as X-ray diff…
The swelling behavior of thin polyelectrolyte multilayers assembled from poly(acrylic acid) and poly(allylamine hydrochloride) under various pH conditions was characterized in real time by in situ single wavelength ellipsometry. Both the rates and extent of swelling were found to be independent of the solution environ…
Abstract The transformation of MoO 3 induced by electron beam irradiation was studied by electron energy‐loss spectroscopy (EELS) in combination with electron diffraction and high‐resolution transmission electron microscopy (HRTEM) techniques. The routes of structure transformation were dependent on the applied electr…
We report on the controlled growth of novel self-assembled nanostructures (nanoaeroplanes, nanocombs, and tetrapod-like networks of zinc oxide) by a simple thermal evaporation technique in a single-stage furnace. Scanning electron microscopy and transmission electron microscopy are used to investigate their morphologi…
Mixtures of five-arm star polystyrene with an organoclay spontaneously formed exfoliated nanocomposites when annealed, validating a recent theoretical prediction by Singh and Balazs (Polym. Int. 2000, 49, 469.). An analogous linear polystyrene sample produced only an intercalated morphology under the same conditions.…
A synthetic glycolipid N -(11- cis -octadecennoyl)-β- d -glucopyranosylamine was employed for the fabrication of organic tubular structures with a cyclic hollow cylinder 30−50 nm wide through molecular self-assembly in water. Gold or silver nanoparticles encapsulated in the hollow cylinders of the lipid nanotubes (LNT…
Abstract Gegenstand dieses Aufsatzes sind neuartige Polyelektrolyt‐Mikrokapseln, einschließlich ihrer Herstellung und Eigenschaften, insbesondere im Hinblick auf ihre mechanischen und Permeationseigenschaften. Die problemlose Präparation durch einen Layer‐by‐Layer‐Selbstorganisationsprozess, die präzise Kontrolle der…
We formed silver nanocrystallites by the thermal decomposition of a Ag+1-oleate complex, which was prepared by a reaction with AgNO3 and sodium oleate in a water solution. The resulting monodispersed silver nanocrystallites were produced by controlling the temperature (290 °C). Transmission electron microscopic (TEM)…
A modified cellular automaton (MCA) coupled with a momentum and species transport model has been developed in order to predict the evolution of dendritic morphology during solidification of alloys in the presence of melt convection. In the present model, the cellular automaton algorithm for dendritic growth is incorpo…
The quasicontinuum method is a way of reducing the number of degrees of freedom in an atomistic simulation by removing the majority of the atoms in regions of slowly varying strain fields. Due to the different ways the energy of the atoms is calculated in the coarse-grained regions and the regions where all the atoms…
Molecular dynamics simulations have been used to study the mechanism of ion beam mixing in metal bilayers. We are able to explain the ion induced low-temperature phase stability and melting behavior of bilayers using only a simple ballistic picture up to 10 keV ion energies. The atomic mass ratio of the overlayer and…
We propose an alternative route to achieve the superconducting state in boron-rich solids, the hole doping of ${\mathrm{B}}_{12}$ icosahedra. For this purpose we consider a prototype metallic phase of ${\mathrm{B}}_{13}{\mathrm{C}}_{2}$. We show that in this compound the boron icosahedral units are mainly responsible…
The effect of a gate voltage ($V_g$) on the spin-splitting of an electronic level in a quantum dot (QD) attached to ferromagnetic leads is studied in the Kondo regime using a generalized numerical renormalization group technique. We find that the $V_g$-dependence of the QD level spin-splitting strongly depends on the…