The relaxor behavior of lanthanum modified lead zirconate titanate (PLZT) ferroelectric ceramics, for a La/Zr/Ti ratio of x/60/40, has been analyzed. An approximation to the dynamical behavior of the polar nano-regions (PNRs) has been discussed, taking into account a relaxation model, which considers a distribution function for the relaxation times. A good agreement between theoretical and experimental results was obtained. The behaviors of the mean relaxation time and its standard deviation with temperature were discussed, considering the correlation between the polar nano-regions and the freezing temperature. The temperature dependence of the polarization showed an anomalous behavior around a temperature, which was associated with the freezing temperature, according to the proposed model in the present work.

This paper examines gender assignment in Spanish–English bilingual speech and develops a theoretical account of gender features in the bilingual grammar on the basis of the linguistic properties that correlate with gender assignment. An analysis of 76 sociolinguistic interviews from an autonomous bilingual community in Southern Arizona, U.S. (Carvalho 2012) reveals three key findings in terms of gender assignment in Spanish Det–English Noun switched DPs (i.e., el industry ‘the.M.SG’): (i) biological sex categorically determines gender assignment with human-denoting nouns; (ii) frequent inanimate nouns that have Spanish feminine counterparts are feminine in bilingual speech; (iii) masculine is a prevailing default gender. Following Kramer’s (2015) proposal of gender features, it is argued that an interpretable [+/-FEM] feature encodes biological sex in the grammar whereby a category-neutral √ combines with a n hosting an interpretable [+/-FEM] feature and triggers feminine (i.e., la coach ‘the.F.SG’) or masculine (i.e., el stepson ‘the.M.SG’) agreement. Inanimate feminine nouns are associated with an uninterpretable [+FEM] feature as the result of bilingualism (i.e., la school ‘the.F.SG’), and masculine default gender is viewed as an effect of Preminger’ (2009) failed Agree. On the basis of these findings, this paper rejects the distinct-lexicons view of the bilingual language faculty (MacSwan 2000 et seq.) and attempts to substantiate a single-lexicon approach compatible with a realizational (Late Insertion) view of the morphosyntactic model (Halle and Marantz 1993).

In this work, we report direct evidence of ferromagnetism in hydrogenated ZnO sub-micrometric powders. Hydrogen (H2) was incorporated under a high-pressure heat treatment in a sealed reactor. Ferromagnetism at room temperature can be activated and deactivated by annealing in H2 and air atmospheres, respectively. Hydrogen incorporation in ZnO structure was observed from X-ray absorption near-edge structure spectra where hydrogen acts as a shallow donor transferring electrons to the conduction band (Zn 4s). The Raman measurements evidence clear distortions in chemical environments of Zn atoms associated with defect formation. Our results suggest that magnetism is a superficial phenomenon probably related to the surface bonding of hydrogen to Zn (or O) on polar ZnO surfaces.

Size-selected TiN nanoclusters in the range of 4 to 20 nm have been produced by an ionized cluster beam, which combines a glow-discharge sputtering with an inert gas condensation technique. With this method, by controlling the experimental conditions, it was possible to produce nanoparticles with a high control in size. The size distribution of TiN nanoparticles was determined before deposition by mass spectroscopy and confirmed by atomic force microscopy. The size distribution was also analyzed using a high-resolution transmission electron micrograph. The photoluminescence [PL] spectra of TiN nanoparticles at different sizes were also experimentally investigated. We reported, for the first time, the strong visible luminescence of TiN nanoparticles on Si (111) wafer due to the reduced size. We also discussed the PL intensity as a function of the nanoparticle size distribution.

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We report the study of ZnO nanorods (ZnO-NR) decorated with BiOI nanoplatelets by the simple precipitation of BiOI in aqueous solution containing ZnO-NR powders. Likewise, as a reference for the decoration of ZnO-NR, BiOI thin films were prepared by the SILAR technique on RF magnetron-sputtered ZnO thin films. The scanning electron microscopy analysis showed that BiOI grew on the ZnO-NR surfaces in nanoplatelet shape with an order of magnitude smaller in size, with respect to the platelets observed in BiOI thin films. Analysis by X-ray diffraction exhibited the hexagonal P63mc phase of ZnO and the tetragonal P4nmm crystal phase of BiOI. On the other hand, BiOI thin films are nonuniform and strongly adherent and, besides they exhibited the P4nmm tetragonal crystal structure of BiOI, they have highly preferential orientation along (001) direction (9.66°). Optical characterization of ZnO-NR/BiOI by absorbance showed a widened peak slightly shifted to infrared compared with the ZnO-NR absorbance peak, suggesting the increase of the absorption wavelength ranges from the ultraviolet to visible for ZnO-NR. Similarly, the results of the optical characterization by absorbance, for BiOI thin films, indicated the bandgap energy of the samples was between 1.78 eV and 1.88 eV, values previously reported for BiOI.

The structural, electronic, and magnetic properties of anatase TiO 2 samples annealed under different hydrogen pressures are reported. By combining X-ray photoelectron spectroscopy (XPS), Raman, UV−vis, and X-ray absorption near-edge structure (XANES) spectroscopies, evidence of hydrogen incorporation was detected in the anatase structure. Short-time high-pressure hydrogen treatment favors the production of interstitial hydrogen, which, located close to a Ti 4+ ion, transfers charge to it, occupying unoccupied 3d levels. Longtime hydrogenation treatments (10 h) help to rebuild the structure of anatase and heal defects, with hydrogen occupying mainly oxygen vacancies. The presence of reduced Ti (4−δ)+ ions gives the sample its magnetic character at room temperature. Our results show that only a small fraction of the sample is magnetic (probably a superficial region affected by the hydrogenation) but the local magnetization is strong (in the order of hundreds of kA/m). By the choice of pressure and duration of treatment in a hydrogen atmosphere, it is possible to change the magnetic characteristics of the sample.

In this work cadmium telluride quantum dots (CdTeQDs) were prepared via one-pot synthesis microwave assisted. Afterwards, CdTeQDs/silica (SiO2)/nigrosine (nigro)/poly (styrene co-methyl methacrylate) (PSCMM) fluorescent nanocomposite (CSNP) powders were prepared via ultrasonic treatment and post drying at 60 ℃. The samples were characterized by UV-vis absorbance, X-Ray diffraction (XRD) and transmission electron microscopy (TEM). Finally, successful printing tests were performed on security paper at 130 ℃. These results show the potential of this