Materials Literature
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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 $n$-…
Analytic solutions for a sonoluminescing gas bubble have been obtained, which provide density, pressure and temperature distributions for the gas inside bubble oscillating under ultrasonic field. The solutions have revealed that sonoluminescence should occur just prior to the bubble collapse and its duration is less t…
The electronic, structural and magnetic properties of all transition-metal mononitrides are investigated by FLAPW band calculations. The equilibrium lattice constants estimated for NaCl-type ScN, TiN and VN and for ZnS-type FeN and CoN are in good agreement with the experimental data. The bulk modulus of MN tends to b…
Many crystalline solids fail by cleavage at low temperatures and by plastic processes at high temperatures. In the transition region, cleavage failure occurs at stresses increasing with increasing temperature, reflecting a decrease in yield stress and a consequent increase of plasticity around the crack tip. Crack tip…
Using a wide-field Kerr microscope, we have studied the magnetic domain structures of epitaxial and polycrystalline La0.67Sr0.33MnO3 thin films as well as a film having thermally induced 〈110〉 microcracks. The epitaxial film on a (001) SrTiO3 substrate has different magnetic domain behaviors for in-plane fields applie…
When molecules are subjected to static or dynamic uniform electric fields the effects are conveniently described in terms of dipole polarizabilities and hyperpolarizabilities. The fields act on both the electronic and vibrational motions simultaneously and, through perturbation theory, this leads to the exact sum-over…