Materials Literature
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We present an extension of the Lubachevsky and Stillinger [J. Stat. Phys. 60, 561 (1990)] packing algorithm to generate packings of polydisperse spheres. The original Lubachevsky–Stillinger algorithm is a nonequilibrium protocol that allows a set of monodisperse spheres to grow slowly over time eventually reaching an…
We demonstrate that the resistivity data of a number of high Tc cuprates, in particular La(2-x)SrxCuO4, are consistent with resistivity saturation, although the Ioffe-Regel condition is strongly violated. By using the f-sum rule together with calculations of the kinetic energy in the t-J model, we show that the satura…
We report the results of measurements of the dc-susceptibility and the 23Na-NMR response of Na2V2O7, a recently synthesized, non metallic low dimensional spin system. Our results indicate that upon reducing the temperature to below 100 K, the V^{4+} moments are gradually quenched, leaving only one moment out of 9 acti…
Recently the conventional notion of random close packing has been supplanted by the more appropriate concept of the maximally random jammed (MRJ) state. This inevitably leads to the necessity of distinguishing the MRJ state among the entire collection of jammed packings. While the ideal method of addressing this quest…
A choice of wireless technologies is available today. Not all of them are suitable to be used in a instrument control network at a neutron scattering facility. This paper will start with an overview of the wireless communication protocols IrDA, IEEE 802.11 WLAN, Bluetooth and protocols used by cellular phones. Afterwa…
We discuss the static deformations of the doped CuO_2 lattices in YBa_2Cu_3O_x. Intrinsic lattice effects driven by the strong correlations of the electron system are separated from extrinsic chemical and bandstructure effects. c-axis displacements of the planar copper atoms seem to be a generic property of the metall…
At FRM-II the installation of a user office software is under consideration, supporting tasks like proposal handling, beam time allocation, data handling and report creation. Although there are several software systems in use at major facilities, most of them are not portable to other institutes. In this paper the req…
Precise control of thermal evaporation deposition parameters allows the reproducible production of silver and gold island films on glass substrates with tunable surface plasmon resonance wavelengths. Specific combinations of substrate temperature, deposition rate, and film thickness produce films exhibiting surface pl…
Aligned single-walled carbon nanotubes are grown onto the surfaces of SiO2/Si substrates in electric fields established across patterned metal electrodes. Calculations of the electric field distribution under the designed electrode structures, the directing ability of electric fields, and the prevention of surface van…
Upon cooling, the isolated ferromagnetic domains in thin films of La0.33Pr0.34Ca0.33MnO3 start to grow and merge at the metal-insulator transition temperature TP1, leading to a steep drop in resistivity, and continue to grow far below TP1. In contrast, upon warming, the ferromagnetic domain size remains unchanged unti…
The strain-gradient-induced polarization (flexoelectric effect) was investigated in Ba0.67Sr0.33TiO3 (BST) ceramic at temperatures above the 21 °C Curie point. At 23 °C the flexoelectric coefficient μ12 was more than one order of magnitude greater than the highest value measured in lead magnesium niobate ceramic. Over…
Although aluminum has a smaller modulus in [111]<112> shear than that of copper, we find by first-principles calculation that its ideal shear strength is larger because of a more extended deformation range before softening. This fundamental behavior, along with an abnormally high intrinsic stacking fault energy and a…
This paper describes a vapor-phase approach to the facial synthesis of cupric oxide (CuO) nanowires supported on the surfaces of various copper substrates that include grids, foils, and wires. A typical procedure simply involved the thermal oxidation of these substrates in air and within the temperature range from 400…
The radiative and nonradiative decay rates of lissamine dye molecules, chemically attached to differently sized gold nanoparticles, are investigated by means of time-resolved fluorescence experiments. A pronounced fluorescence quenching is observed already for the smallest nanoparticles of 1 nm radius. The quenching i…
Small-angle x-ray scattering (SAXS) measurements have been performed to investigate particle morphology during in situ hydrogen evolution from a 1000-\AA{} epitaxial Nb film on $(112\ifmmode\bar\else\textasciimacron\fi{}0)$ sapphire initially loaded to saturation with hydrogen. The SAXS intensity follows the plate or…
Abstract From a rheological study of emeraldine base (EB)/ N ‐methyl‐2‐pyrrolidinone (NMP)/2‐methyl‐aziridine (2MA) solutions, a correlation between the solution concentration and solution viscosity was found. We investigated the rheokinetic mechanism of the EB dissolution process and determined the reaction rate, act…
The γ-brass type phase Pt2Zn11—δ (0.2 < δ < 0.3) was prepared by reaction of the elements in evacuated silica ampoules. The structures of crystals grown in the presence of excess zinc or alternatively excess platinum were determined from single crystal X-ray diffraction intensities and confirmed by Rietveld profile fi…
For the enhancement of the compatibility of fluoropolymers with other materials radiation modification is applied, for which irradiation with high-energy electrons provides an efficient and flexible possibility. Poly(tetrafluoroethylene) (PTFE) is known to predominantly undergo chain scission under irradiation. To cou…
Magnetic domain structures of $\mathrm{N}{\mathrm{d}}_{\mathrm{1}\mathrm{/}\mathrm{2}}\mathrm{S}{\mathrm{r}}_{\mathrm{1}\mathrm{/}\mathrm{2}}\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{3}}$ were investigated by means of low-temperature Lorentz electron microscopy. On cooling, magnetic domain walls started to appear at 2…
We have evidenced by small-angle neutron scattering at low temperature the coexistence of ferromagnetism (F) and antiferromagnetism (AF) in ${\mathrm{P}\mathrm{r}}_{0.67}\mathrm{C}{\mathrm{a}}_{\mathrm{0.33}}\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{3}}$. The results are compared to those obtained in ${\mathrm{P}\math…