Materials Literature
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Infrared microspectroscopy with a high brightness synchrotron source can achieve a spatial resolution approaching the diffraction limit. However, in order to realize this intrinsic source brightness at the specimen location, some care must be taken in designing the optical system. Also, when operating in diffraction l…
First principles calculations based on density functional theory are having an incerasing impact on our understanding of molecule-surface interactions. For example, calculations of the multi-dimensional potential energy surface have provided considerable insight into th edynamics of dissociation processes. However, th…
The Yb atom in the title compound, K[Yb(C10H12N2O8)(H2O)2].5H2O, is eight coordinate through two N and four O atoms in edta, and two water O atoms, where edta denotes ethylenediaminetetraacetate. The geometry around the Yb atom is influenced by the size and electrostatic properties of the counter cations.
Using a nonstandard preparation procedure, porous silicon (PS) samples are grown whose overall photoluminescence (PL) intensities exceed those of standard PS samples from the same Si wafer up to 50 times, and whose PL maxima occur in the high-energy range at about 1.8 eV. The preparation includes an electrochemical et…
Anisotropic and isotropic Sm2Co17-type permanent magnets have been prepared by using the conventional sintering technique. Transmission electron microscopy was used to characterize the cellular structure within the Sm2(Fe,Co)17 grains. Hysteresis loops (M∼H) were measured in the temperature range from 4.2 to about 100…
Crystals of a new nesosilicate, tricalcium diyttrium trisilicon oxide, Ca3Y2(SiO4)3, were prepared from a silicate melt by slow cooling. The structure was refined in space group Pnma and has nine-, eight- and seven-coordinate sites for Ca2+ and Y3+ cations. The structural formula can be expressed as (Ca0.84Y0.16) (Ca0…
An extensive investigation of the fluorescence dynamics of the (2H11/2,4S3/2), 4F9/2, 4I9/2, 4I11/2, and 4I13/2 states was carried out for 0.1%, 1%, 2.5%, and 10% Er3+ doped in YVO4. The decay profiles of the luminescence of the 4S3/2 level of Er3+ (1.0%) obey the Inokuti–Hirayama model for energy transfer for an elec…
Several experimental and computer simulation studies have found a partial decoupling between the diffusion coefficient of a small tagged particle from the viscosity of the medium in the supercooled liquid regime. In order to understand the microscopic origin of this decoupling, we have carried out detailed theoretical…
The linear thermal expansion coefficients of fused quartz containing 3 ppm of OH produced by electrical melting of natural quartz powder were measured using an interferometric dilatometer in the temperature range 300–970 K. The data obtained show several maxima and minima, some of which correspond to the phase transit…
The volume dependence of the potential energy landscapes of glasses is examined. Glassy structures, corresponding to local potential energy minima, are compressed and expanded. The local minima often disappear with volume changes, after which the system becomes mechanically unstable and subsequently relaxes to a diffe…
The emission properties of para-hexaphenyl polycrystalline films are investigated by combining time-resolved photoluminescence and pump-probe measurements with site-selective spectroscopy. Photoinduced absorption, gain, and photoluminescence exhibit the same temporal behavior, showing that the same emitting species ar…
A new refinement of a single monoclinic crystal of brochantite, Cu4SO4(OH)6, from Socorro, New Mexico, USA, yielded new, accurate positions for Cu, S and O. Five of the six H atoms were located from Fo-Fc syntheses.
The crystal structure of the title copper molybdate consists of strings of corner-sharing CuO6 octahedra linked to CuO5 square pyramids and MoO4 tetrahedra by edges and corners, respectively. The structure contains the Jahn-Teller active ion Cu2+ in unusual compressed octahedral coordination.
Silicon photodiodes offer a number of advantages over conventional photocathode type soft x-ray detectors in pulsed power experiments. These include a nominally flat response, insensitivity to surface contamination, low voltage biasing requirements, sensitivity to low energy photons, excellent detector to detector res…
We report temperature-dependent far- and midinfrared reflectivity spectra of ${\mathrm{LaNi}}_{(1\ensuremath{-}x)}{\mathrm{Fe}}_{x}{\mathrm{O}}_{3}$ $(0.00<~x<~1.00)$ solid solutions that span the passage from ${\mathrm{LaFeO}}_{3},$ a room-temperature antiferromagnetic insulator, to ${\mathrm{LaNiO}}_{3},$ a kn…
On the basis of observations made by electron microscopy of the distribution of dislocations around undeformable particles embedded in a matrix of plastic crystalline metal, it is possible to see a clear transition from ‘laminar plastic flow’ to ‘rotational flow’ at a critical strain which depends mostly upon the part…
We investigated the interface between a three-dimensional substrate, Si, and a layered compound, GaSe, in the very first steps of the growth. Atomic models, related to deposits of 1.5 and 2.5 sheets, respectively, were derived from grazing incidence x-ray diffraction. They are based on the bulk phases, that is, on ${\…
The union of calcium cations with carbonate anions to form calcium carbonate (CaCO3) is a fundamentally important physiological process of many marine invertebrates, in particular the corals. In an effort to understand the sources and processes of carbon uptake and subsequent deposition as calcium carbonate, a series…
A microstructural analysis of silicon-on-insulator samples obtained by high dose oxygen ion implantation was performed by Raman scattering. The samples analyzed were obtained under different conditions thus leading to different concentrations of defects in the top Si layer. The samples were implanted with the surface…
The dc resistance and the temperature coefficient of resistance (TCR) of bulk nanostructured silver ($n$-Ag), synthesized by inert gas condensation and in situ vacuum compaction as well as by the sol-gel method, was investigated in the temperature range from 4.2 to 300 K. The results indicated that for all of the $n$-…