Materials Literature
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We suggest a model of the atomic and electronic processes responsible for the so-called 110 and 325 °C thermoluminescence (TL) peaks, including predose behavior, and for the room temperature optically stimulated luminescence (OSL) of quartz. Our model is based on defects and defect processes typical of those known fro…
We report, for the first time, deviations from the Summerfield scaling in the ac conductivity spectra of single ion conducting glasses. In contrast to the extensively studied borate and germanate glasses, the conductivity isotherms of alkali tellurite glasses do not superimpose upon application of the Summerfield scal…
Fe–Ga alloys with compositions near 27.5 at. % Ga (26–29 at. %) can be heat treated to obtain ordered phases based on α″ (ordered bcc), D019 (ordered hexagonal), and L12 (ordered fcc) structures. This work presents an evaluation of how the different ordering treatments influence the magnetostriction in cast polycrysta…
${\mathrm{Pd}}_{43}{\mathrm{Ni}}_{10}{\mathrm{Cu}}_{27}{\mathrm{P}}_{20}$ has been investigated in its equilibrium liquid state with incoherent, inelastic neutron scattering. As compared to simple liquids, liquid ${\mathrm{Pd}}_{43}{\mathrm{Ni}}_{10}{\mathrm{Cu}}_{27}{\mathrm{P}}_{20}$ is characterized by a dense pack…
Coupling phenomena between artificial left-handed (LH) transmission lines are explored on the basis of a transmission line approach of LH materials. A LH forward coupler in the form of an ideal lumped-element ladder network is presented and is shown to exhibit strong forward coupling that increases with decreasing of…
Previous theoretical simulation and experimental studies have indicated that particles with a short-ranged attraction exhibit a range of dynamical arrest phenomena. These include very pronounced reentrance in the dynamical arrest curve, a logarithmic singularity in the density correlation functions, and the existence…
We have studied the thickness dependence of the magnetotransport properties of ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ thin films epitaxially grown on ${\mathrm{SrTiO}}_{3},$ ${\mathrm{LaAlO}}_{3},$ and ${\mathrm{NdGaO}}_{3}$ single-crystalline substrates. When thickness decreases, a global disrupti…
Abstract The effect of the chain constraint on the glass‐transition temperature of polystyrene (pS) was studied in the context of polymer tethering to curved surfaces. The synthesis and characterization of silica‐ graft ‐polystyrene (SiO 2 ‐ g ‐pS) hybrid nanoparticles is reported. Silica nanoparticles possessing cova…
The approaches that form the basis of automated structure solution in SOLVE and RESOLVE are described. The use of a scoring scheme to convert decision making in macromolecular structure solution to an optimization problem has proven very useful and in many cases a single clear heavy-atom solution can be obtained and u…
Abstract The morphologies and crystalline structures of melt‐crystallized ultrathin isotactic poly(1‐butene) films have been studied with transmission electron microscopy and electron diffraction. It is demonstrated that a bypass of form II crystallization can be achieved with an increase in its crystallization temper…
The magnetization of an ensemble of isolated lead grains of sizes ranging from below 6 nm to 1000 nm is measured. A sharp disappearance of Meissner effect with lowering of the grain size is observed for the smaller grains. This is a direct observation by magnetization measurement of the occurrence of a critical partic…
The World Wide Web (WWW) is a wonderful tool to provide users with documentation and tools that make the preparation and running of an experiment a little easier. We present a set of tools that allow one to estimate the activation of a sample in the neutron beam, or to calculate the absorption of a sample. Ever tried…
MX is a portable beamline control system that has been described at previous NOBUGS meetings. This talk will briefly review MX and then discuss important changes and improvements made since the last meeting in 2000. For materials science, work has focused on extending the support for multichannel analyzers and for fas…
The development of control software for a neutron powder diffraction instrument at the Safari-1 research reactor of South Africa is reported. The software runs under Windows 2000 and incorporates PC-based cards for data acquisition and motion control. It has the capability to collect data from multiple detectors and c…
This new package will provide easy-to-use access to crystallographic structure solution, model building and structure analysis. It will be possible for any developer to integrate scientific software into the system.
A detailed analysis of the formation energies for alkali, earth-alkali, and transition-metal hydrides is presented. The hydriding energies are computed for various crystal structures using density functional theory. The early transition metals are found to have a strong tendency for hydride formation which decreases a…
Abstract Organically modified montmorillonite was synthesized with a novel 1,2‐dimethyl‐3‐ N ‐alkyl imidazolium salt or a typical quaternary ammonium salt as a control. Poly(ethylene terephthalate) montmorillonite clay nanocomposites were compounded via melt‐blending in a corotating mini twin‐screw extruder operating…
The field emission of individual multiwall carbon nanotubes grown by chemical vapor deposition was measured in a scanning electron microscope. By using a sharp anode, we were able to select one nanotube for measurements in carefully controlled conditions. Single nanotubes follow the Fowler-Nordheim law, and the depend…
Structural genomics seeks to expand rapidly the number of protein structures in order to extract the maximum amount of information from genomic sequence databases. The advent of several large-scale projects worldwide leads to many new challenges in the field of crystallographic macromolecular structure determination.…
Transparent sols of crystalline gadolinium doped zirconia particles with the general formula Zr 1 - x Gd x O 2 - x/2 (where x = 0–0.20), were prepared by a hydrothermal sol-gel method using cheap inorganic precursors. The composition, structure, crystallite size and lattice parameters of the crystalline dried sol part…