Materials Literature
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Transition metal oxide cations of the form M n O m (+) (M = Y, La) are produced by laser vaporization in a pulsed nozzle source and detected with time-of-flight mass spectrometry. Cluster oxides for each value of n form only a limited number of stoichiometries; MO(M2O3)x(+) species are particularly intense. Cluster ca…
The photoluminescence features of Eu(3+)-, Tb(3+)-, Tb(3+)/Eu(3+)-alginate aerogel (hydrogel and alcogel) and Eu(3+)-alginate xerogel hybrids were investigated. The Eu(3+)-alginate aerogel and alcogel exhibit the highest (5)D0 quantum efficiencies (9.9 and 8.2%, respectively), while the hydrogel and xerogel have lower…
The dynamic structure factor $S(Q,\ensuremath{\omega})$ of liquid Fe was measured at $1570\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ near the melting point of $1535\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ by using a high-resolution inelastic x-ray scatter…
In the present study, we describe a multimodal QD probe with combined fluorescent and paramagnetic properties, based on silica-shelled single QD micelles with incorporated paramagnetic substances [tris(2,2,6,6-tetramethyl-3,5-heptanedionate)/gadolinium] into the micelle and/or silica coat. The probe was characterized…
The pH-controlled assembly of gold nanoparticles within a polymer−gold nanoparticle (AuNP) composite material is described. Poly(allylamine) (PAAm) is used as a reducing and stabilizing agent to generate a stable water-soluble polymer−AuNPs composite. The optical properties and the morphology of the composite material…
Porous scaffolds for tissue engineering applications based on poly(D,L-lactide)/poly(epsilon-caprolactone) compatibilized blends are described. The addition of a third polymer, namely poly( D, L-lactide-co-caprolactone) copolymer, has a profound effect on morphological properties of the blends scaffolds. In fact, the…
The objective of this work was to lower the sintering temperature of K 0.5 Na 0.5 NbO 3 (KNN) without reducing its piezoelectric properties. The KNN was sintered using 0.5, 1, 2, and 4 mass% of (K, Na)‐germanate. The influence of the novel sintering aid, based on alkaline germanate with a melting point near 700°C, on…
The use of urea as a precipitating agent in the synthesis of Ni-Al and Zn-Al layered double hydroxides having a hydrotalcite-like structure via a microwave-hydrothermal method is reported. For comparison purposes, the samples were also prepared by a conventional hydrothermal method. Ni-Al compounds with the hydrotalci…
We examine the photoconductivity of an intrinsic graphene associated with far- and midinfrared irradiation at low temperatures. The model under consideration accounts for the excitation of the electron-hole pairs by incident radiation, the interband generation-recombination transitions due to thermal radiation, and th…
The ideal strengths, electronic density of states, and charge density difference of wurtzite $w$-BN had been calculated by ab initio density functional theory and compared to zincblende $c$-BN. Both polymorphs show a different stacking of lattice planes but have comparable anisotropic strengths, which are due to the s…
The specific heat $C(T)$ of iron-based high-${T}_{c}$ superconductor ${\mathrm{SmO}}_{1\ensuremath{-}x}{\mathrm{F}}_{x}\mathrm{FeAs}$ $(0\ensuremath{\le}x\ensuremath{\le}0.2)$ was systematically studied. For the undoped $x=0$ sample, a specific heat jump was observed at $130\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. This…
We demonstrate a novel index-guided (IG) photonic crystal fiber (PCF) surface-enhanced Raman probe. Different from a regular PCF, the IGPCF has four big air holes inserted between the solid silica core and the photonic crystal cladding holes. The gold nanoparticles, serving as the surface enhanced Raman scattering (SE…
A lattice model is used to estimate the self-diffusivity of entangled cyclic and linear polymers in blends of varying compositions. To interpret simulation results, we suggest a minimal model based on the physical idea that constraints imposed on a cyclic polymer by infiltrating linear chains have to be released, befo…
A simple method for the fabrication of metal nanoparticles is introduced. Heating metal-organic crystals in vacuum results in the formation of well defined metal particles embedded in a carbon matrix. The method is demonstrated for iron-phthalocyanine. At 500C homogeneously distributed iron nanoparticles with a reason…
Carrier relaxation due to both optical and nonradiative intraband transitions in silicon quantum dots in SiO$_2$ has been considered. Interaction of confined holes with optical phonons has been studied. The Huang-Rhys factor is calculated for such transitions. The probability of intraband transition of a confined hole…
We develop a theory of anomalous quantum Hall effects in graphene. We demonstrate that the Landau level structure by itself is not sufficient to determine the form of the quantum Hall effect. It is only a special symmetry of disorder that gives rise to anomalous quantization of Hall conductivity in graphene. We analyz…
It is argued that topological disorder in amorphous solids can be described by local strains related to local reference crystals and local rotations. An intuitive localization criterion is formulated from this point of view. The Inverse Participation Ratio and the location of mobility edges in band tails is directly r…
Conductance of an Au mono atomic contact was investigated under the electrochemical potential control. The Au contact showed three different behaviors depending on the potential: 1 $G_{0}$ ($G_{0}$ = $2e^{2}/h$), 0.5 $G_{0}$ and not-well defined values below 1 $G_{0}$ were shown when the potential of the contact was k…
The structural, dielectric and dynamical properties of the low temperature antiferromagnetic orthorhombic phase of CaMnO 3 have been computed from first principles, using a density functional theory approach within the local spin density approximation. The theoretical structural parameters are in good agreement with e…
Sodium exhibits a pronounced minimum of the melting temperature at approximately 118 gigapascals and 300 kelvin. Using single-crystal high-pressure diffraction techniques, we found that the minimum of the sodium melting curve is associated with a concentration of seven different crystalline phases. Slight changes in p…