Materials Literature
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Monte Carlo simulations of the magnetoelectric coupling between ferroelectric order and magnetic order in ferroelectromagnets are performed based on the Janssen model in which the electric and magnetic subsystems are coupled. The simulations reveal that a weak ferromagnetic transition can be activated both by the stro…
Molecular structures of 12 porphyrin analogues, Fe(III)(EtioP)X(1(a)-1(d)), Fe(III)(EtioCn)X(2(a)-2(d)), and Fe(III)(Etio-Pc)X(3(a)-3(d)), where X = F (a), Cl (b), Br (c), and I (d), are determined on the basis of X-ray crystallography. Combined analyses using Mössbauer, (1)H NMR, and EPR spectroscopy as well as SQUID…
We extend our original parametric formulation of the Fourier modal method to the case of lamellar gratings that are periodic in two directions. We provide numerical evidence that improved convergence rates can be obtained for dielectric and metallic gratings.
A significant reduction of absorption for single gamma photons has been experimentally observed by studying M\"ossbauer spectra of $^{\mathrm{57}}\mathrm{F}\mathrm{e}$ in a ${\mathrm{F}\mathrm{e}\mathrm{C}\mathrm{O}}_{3}$ crystal. The experimental results have been explained in terms of a quantum interference effect i…
Extended duration in situ variable-temperature atomic force microscopy performed on a series of coacervating hydrophobic peptides based on human elastin revealed a novel multistage surface assembly process. Formation of epitaxially arranged peptide rods was preceded by rapid expansion of a two-dimensional film on the…
We present the synthesis and characterization of new light-harvesting arrays containing two, four, or eight perylene-monoimide accessory pigments attached to a zinc porphyrin. Each perylene is substituted with one or three 4-tert-butylphenoxy substituents. A 4,3'- or 4,2'-diarylethyne linker joins the perylene N-imide…
The size-dependent transient photoconductivity in CdSe nanoparticles (NPs) has been investigated using time-resolved THz spectroscopy (TRTS). We find that the mobility increases with an r 4 dependence for NPs in the strong confinement regime and is governed by a restricted mean free path for NPs in the weak confinemen…
CdSe and CdTe nanowires were prepared through a poly(vinyl alcohol) (PVA) assisted ethylenediamine solvothermal method in 160−180 °C. The PVA used in the process was favorable for the formation of nanowires. X-ray diffraction (XRD) shows that the CdSe nanowires are mostly in zinc blende phase and CdTe ones are in zinc…
We propose an explanation of the anomalous growth of plasticity in ferromagnets near the Curie point. We demonstrate that this effect is caused by spin-dependent detachment of dislocations from obstacles under an influence of the internal magnetic field. Magnetization fluctuations grow in the vicinity of the Curie poi…
We report dc transport and magnetization measurements of Jc in MgB2 wires fabricated by the powder-in-tube method, using commercial MgB2 powder with 5 %at Mg powder added as an additional source of magnesium, and stainless steel as sheath material. By appropriate heat treatments, we have been able to increase Jc by mo…
We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested S…
We have investigated the nonlinear microwave properties of electron-beam coevaporated YBaCuO films on MgO, using stripline resonators at 2.3 GHz and temperatures 1.7-80 K. The oxygen content of the films ranged from strongly underdoped to overdoped. Above 20 K, the nonlinear response of the resonators was dominated by…
Aqueous solutions of a methylcellulose, ranging from 0.30 to 2.49 wt %, were studied by means of micro differential scanning calorimetry (micro DSC) and rheology. The effects of polymer concentration on the thermodynamic properties of these solutions were examined through a heating process and a following cooling proc…
Arrays of graphitic carbon nanoclusters were obtained by pyrolysis of nanoscale phase-separated block copolymers of polyacrylonitrile and poly(n-butyl acrylate). Upon heating in an inert atmosphere to temperatures ranging from approximately 400 to 1200 degrees C, polyacrylonitrile domains were converted into carbon na…
Supported Au catalysts are very selective for the direct formation of hydrogen peroxide from H2/O2 mixtures at 2 degrees C; the rate of H2O2 synthesis is markedly increased if Au-Pd alloy nanoparticles are generated by the addition of Pd.
The electrical field arising around an inhomogeneous conductor when an electrical current passes through it is not screened, as distinct from 3D conductors, in low-dimensional conductors. As a result, the electrical field depends on the global distribution of the conductivity sigma(x) rather than on the local value of…
[reaction: see text] Helical polyacetylene fibers with absolutely symmetric structures were prepared by polymerization of acetylene using copper tartrate as a catalyst. There were always only two coiled polyacetylene fibers grown on a single copper nanocrystal. The two coiled fibers had absolutely opposite helical sen…
Abstract To investigate the role of the internal donor in a Ziegler–Natta catalyst, the nature and existing states of the internal donor were intentionally varied by alkylaluminium treatment before polymerization, and the catalytic properties during propene polymerization were accurately evaluated using the stopped‐fl…
A meso -tetraphenylporphyrin derivative with two butanethiol and two carboxylate groups on opposite phenyl substituents was first covalently bound to citrate gold particles by a self-assembly procedure. In a second self-assembly step the remaining areas on the gold surface were covered with a monolayer of a bolaamphip…
Abstract This work is focused on the analysis of the scale‐up process of styrene drying by adsorption onto activated alumina as a necessary step in the manufacture of styrene–butadiene rubber. In a previous work, the mathematical model was developed and the design parameters were estimated from the fitting of the mode…