240 research outputs found

    Nueva solución trigonométrica para la corrección de buzamientos sobreimpuestos en capas deformadas

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    [ES] Se presenta una nueva solución trigonométrica al problema de las dos inclinaciones, así como un programa FORTRAN IV para el procesado automático de los datos a corregir.[EN] A new trigotiometric solution to the two tilts problem is presented, so as a FORTRAN IV program for the automatic processing of data to be corrected.Peer reviewe

    Optical and magnetic properties of ZnCoO thin films synthesized by electrodeposition

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    Ternary Zn1−xCoxO crystalline films with different compositions were grown by electrodeposition. The Co content in the final compound is linked to the initial Co/Zn ratio in the starting solution. X-ray diffraction reveals a wurtzite structure for the Zn1−xCoxO films. Transmittance spectra show two effects proportional to Co content, a redshift of the absorption edge and three absorption bands, which are both interpreted to be due to the Co incorporated into the ZnO lattice. The amount of deposited charge was used to get a precise control of the film thickness. Magnetic measurements point out that Co(II) ions are isolated from each other, and consequently the films are [email protected]

    Synthesis and down conversion emission property of Eu3+ doped LaAlO3 CsAlO2 and LiLaO2 phosphors

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    [EN] LaAlO3:Eu3+, CsAlO2:Eu3+ and LiLaO2:Eu3+ phosphors with varying concen- trations of Eu3+ from 3 to 10 mol% were prepared by combustion synthesis method and the samples were further heated to 1,000ºC to improve the crystallinity of the materials. The structure and morphology of materials have been examined by X-ray diffraction and scan- ning electron microscopy. SEM images depicted that the morphology of crystallites have no uniform shapes and sizes. Small and coagulated particles of irregular shapes of different sizes are obtained. The characteristic emissions of Eu3+ were clearly observed at nearly 580, 592, 650, 682 to 709 (multiplet structure) nm for 5D - 7 Fn transitions where n = 0, 1, 3, 4 respectively, including the strongest emission peaks at 614 and 620 nm for 5 D0 - 7 F2 transitions in CsAlO2:Eu3+ and LiLaO2:Eu3+ host lattices. The intensity of emission peak corresponding to 5 D0 !→ 7 F1 transitions in LaAlO3 :Eu3+ material is comparable to that of 5D0 5D-7F2 transitions which is also a singlet. Photoluminescence intensity follows the order as in LiLaO2 > LaAlO3 > CsAlO2 lattices. Remarkable high photoluminescence intensity with 7 mol% doping of Eu3+ in LiLaO2 makes it a strong contender for red colored display applications.This work was supported by the European Commission through Nano CIS project (FP7-PEOPLE-2010-IRSES ref. 269279).Marí Soucase, B.; Singh, KC.; Moya Forero, MM.; Singh, I.; Om, H.; Chand, S. (2015). Synthesis and down conversion emission property of Eu3+ doped LaAlO3 CsAlO2 and LiLaO2 phosphors. Optical and Quantum Electronics. 47(7):1569-1578. https://doi.org/10.1007/s11082-014-9997-9S15691578477Abbattista, F., Vallino, M.: Remarks on the La2O3Li2O\text{La}_{2}\text{O}_{3}-\text{Li}_{2}\text{O} La 2 O 3 - Li 2 O binary system between 750 and 1,000  ^{\circ} ∘ C. Ceram. Int. 9, 35–38 (1983)Bae, Y., Lee, K., Byeon, S.: Synthesis and Eu3+\text{Eu}^{3+} Eu 3 + concentration-dependent photoluminescence of Gd2xEuxO3\text{Gd}_{\rm 2-x}\text{Eu}_{\rm x}\text{O}_{3} Gd 2 - x Eu x O 3 nanowires. J. Lumin. 129, 81–85 (2009)Blasse, G., Grambier, B.: Luminescent Materials, vol. 43. Springer, Berlin, pp. 43–46 (1994)Dereń, P., Krupa, J.: Spectroscopic investigations of LaAlO3\text{LaAlO}_{3} LaAlO 3 : Eu3+\text{Eu}^{3+} Eu 3 + . J. Lumin. 102–103, 386–390 (2003)Ekambaram, S., Patil, K.: Synthesis and properties of Eu2+\text{Eu}^{2+} Eu 2 + activated blue phosphors. J. Alloys Compd. 248, 7–12 (1997)Gao, X., Lei, L., Lv, C., Sun, Y., Zheng, H., Cui, Y.: Preparation and photoluminescence property of a loose powder, Ca3Al2O6\text{Ca}_{3}\text{Al}_{2}\text{O}_{6} Ca 3 Al 2 O 6 : Eu3+\text{Eu}^{3+} Eu 3 + by calcination of a layered double hydroxide precursor. J. Solid State Chem. 181, 1776–1781 (2008)Hayakawa, T., Kamt, N., Yamada, K.: Visible emission characteristics in Tb3+\text{Tb}^{3+} Tb 3 + -doped fluorescent glasses under selective excitation. J. Lumin. 68, 179–186 (1996)Hreniak, D., Strek, W., Dereń, P., Bednarkiewicz, A., Łukowiak, A.: J. Alloys Compd. 408, 828–830 (2006)Huang, Y., Jiang, C., Cao, Y., Shi, L., Seo, H.: Luminescence and microstructures of Eu3+\text{Eu}^{3+} Eu 3 + -doped in triple phosphate Ca8MgR(PO4)7\text{Ca}_{8}\text{MgR}(\text{PO}_{4})_{7} Ca 8 MgR ( PO 4 ) 7 (R = La, Gd, Y) with whitlockite structure. Mater. Res. Bull. 44, 793–798 (2009)Kharbache, H., Mahiou, R., Boutinaud, P., Boyer, D., Zakaria, D., Deren, P.: Experimental evidence of Eu3+\text{Eu}^{3+} Eu 3 + pairs in K2EuF5\text{K}_{2}\text{EuF}_{5} K 2 EuF 5 . Opt. Mater. 31, 558–561 (2009)Kijima, T., Shinbori, T., Sekita, M., Uota, M., Sakai, G.: Abnormally enhanced Eu3+\text{Eu}^{3+} Eu 3 + emission in Y2O2SO4\text{Y}_{2}\text{O}_{2}\text{SO}_{4} Y 2 O 2 SO 4 : Eu3+\text{Eu}^{3+} Eu 3 + inherited from their precursory dodecylsulfate-templated concentric-layered nanostructure. J. Lumin. 128, 311–316 (2008)Liu, G., Hong, G., Wang, J., Dong, X.: Hydrothermal synthesis of spherical and hollow Gd2O3\text{Gd}_{2}\text{O}_{3} Gd 2 O 3 : Eu3+\text{Eu}^{3+} Eu 3 + phosphors. J. Alloys Compd. 432, 200–204 (2007)Mączka, M., Bednarkiewicz, A., Mendoza-Mendoza, E., Fuentes, A.F., Kępiński, L.: Optical properties of Eu and Er doped LaAlO3\text{LaAlO}_{3} LaAlO 3 nanopowders prepared by low-temperature method. J. Solid State Chem. 194, 264–269 (2012)Mao, Z., Wang, D., Lu, Q., Yu, W., Yuan, Z.: Tunable single-doped single-host full-color-emitting LaAlO3\text{LaAlO}_{3} LaAlO 3 : Eu\text{Eu} Eu phosphor via valence state-controlled means. Chem. Commun. 3, 346–348 (2009)Mao, Z.Y., Wang, D.J., Liu, Y.H., Fei, Q.N., Zheng, X., Xu, S.C., Qiu, K.: Tuning the color purity of LaAlO3\text{LaAlO}_{3} LaAlO 3 : Eu3+\text{Eu}^{3+} Eu 3 + red phosphor by the cross relaxation. Opto Electron. Lett. 6, 116–119 (2010)Marí, B., Singh, K., Sahal, M., Khatkar, S., Taxak, V., Kumar, M.: Preparation and luminescence properties of Tb3+\text{Tb}^{3+} Tb 3 + doped ZrO2\text{ZrO}_{2} ZrO 2 and BaZrO3\text{BaZrO}_{3} BaZrO 3 phosphors. J. Lumin. 130, 2128–2132 (2010)Marí, B., Singh, K.C., Cembrero-Coca, P., Singh, I., Singh, D., Chand, S.: Red emitting MTiO3\text{MTiO}_{3} MTiO 3 (M = Ca & Sr) phosphor doped with Eu+3\text{Eu}^{+3} Eu + 3 or Pr+3\text{Pr}^{+3} Pr + 3 with some cations as co-dopands. Displays 34, 346–351 (2013)Ningthoujam, R., Sudarsan, V., Kulshreshtha, S.: SnO2\text{SnO}_{2} SnO 2 : Eu\text{Eu} Eu nanoparticles dispersed in silica: A low-temperature synthesis and photoluminescence study. J. Lumin. 127, 747–756 (2007)Ogasawara, K., Watanabe, S., Toyoshima, H., Brik, M.G.: Handbook on Physics and Chemistry of Rare Earths, vol. 1. Elsevier, Amsterdam (2007)Pereyra-Perea, E., Estrada-Yañez, M.R., García, M.: Preliminary studies on luminescent terbium-doped ZrO2 thin films prepared by the sol-gel process. J. Phys. D 31, 7–10 (1998)Perez, D., Vegas, A.: The Zintl-Klemm concept applied to cations in oxides. I. The structures of ternary aluminates. Acta Cryst. B 59, 305–323 (2003)Pieterson, L., Heeroma, M., Heer, E., Meijerink, A.: Charge transfer luminescence of Yb3+\text{Yb}^{3+} Yb 3 + . J. Lumin. 91, 177–193 (2000)Shi, C., Shi, J., Deng, J., Han, Z., Zhou, Y., Zhang, G.: Excitation states of RE3+\text{RE}^{3+} RE 3 + -pentaphosphates in VUV and UV range. J. Electron. Spectros. Relat. 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Solids 69, 2877–2882 (2008

    Positron lifetime measurements on neutron‐irradiated InP crystals

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    Neutron‐irradiated InP single crystals have been investigated by positron‐lifetime measurements. The samples were irradiated with thermal neutrons at different fluences yielding concentrations for Sn‐transmuted atoms between 2×1015 and 2×1018 cm−3. The lifetime spectra have been analyzed into one exponential decay component. The mean lifetimes show a monotonous increase with the irradiation dose from 246 to 282 ps. The increase in the lifetime has been associated to a defect containing an Indium vacancy. Thermal annealing at 550 °C reduces the lifetime until values closed to those obtained for the as‐grown and conventionally doped InP [email protected] ; [email protected]

    Radon and material radiopurity assessment for the NEXT double beta decay experiment

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    The Neutrino Experiment with a Xenon TPC (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.Comment: Proceedings of the Low Radioactivity Techniques 2015 workshop (LRT2015), Seattle, March 201

    The Tate conjecture for K3 surfaces over finite fields

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    Artin's conjecture states that supersingular K3 surfaces over finite fields have Picard number 22. In this paper, we prove Artin's conjecture over fields of characteristic p>3. This implies Tate's conjecture for K3 surfaces over finite fields of characteristic p>3. Our results also yield the Tate conjecture for divisors on certain holomorphic symplectic varieties over finite fields, with some restrictions on the characteristic. As a consequence, we prove the Tate conjecture for cycles of codimension 2 on cubic fourfolds over finite fields of characteristic p>3.Comment: 20 pages, minor changes. Theorem 4 is stated in greater generality, but proofs don't change. Comments still welcom

    NEXT-100 Technical Design Report (TDR). Executive Summary

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    In this Technical Design Report (TDR) we describe the NEXT-100 detector that will search for neutrinoless double beta decay (bbonu) in Xe-136 at the Laboratorio Subterraneo de Canfranc (LSC), in Spain. The document formalizes the design presented in our Conceptual Design Report (CDR): an electroluminescence time projection chamber, with separate readout planes for calorimetry and tracking, located, respectively, behind cathode and anode. The detector is designed to hold a maximum of about 150 kg of xenon at 15 bar, or 100 kg at 10 bar. This option builds in the capability to increase the total isotope mass by 50% while keeping the operating pressure at a manageable level. The readout plane performing the energy measurement is composed of Hamamatsu R11410-10 photomultipliers, specially designed for operation in low-background, xenon-based detectors. Each individual PMT will be isolated from the gas by an individual, pressure resistant enclosure and will be coupled to the sensitive volume through a sapphire window. The tracking plane consists in an array of Hamamatsu S10362-11-050P MPPCs used as tracking pixels. They will be arranged in square boards holding 64 sensors (8 times8) with a 1-cm pitch. The inner walls of the TPC, the sapphire windows and the boards holding the MPPCs will be coated with tetraphenyl butadiene (TPB), a wavelength shifter, to improve the light collection.Comment: 32 pages, 22 figures, 5 table

    Communication, development, and social change in Spain: A field between institutionalization and implosion

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    This paper renders an account of the rapid institutionalization of the academic field of Communication for Development and Social Change (CDCS) in Spain in recent years following a period of neglect and marginalization. The ongoing expansion of the field of CDSC in the Spanish context is understood as a process of implosion, i.e. a collapse inwards, which results from the inconsistencies and weaknesses of fast and late institutionalization. The methodological approach for this inquiry is a documental review of both academic literature and research and institutional reports produced in Spain between 1980 and 2010. Based on this review, the paper contrasts the trajectory of the field in Spain with the debates at the international level, establishing relevant continuities and differences.This article is part of the Research Project (Ministry of Economy and Competitiveness, Spain) CSO2014-52005-R titled ‘Evaluation and Monitoring of Communication for Development and Social Change in Spain: design of indicators to measure its social impact’ (2015–2017)17 página

    Trends in socioeconomic inequalities in mortality in small areas of 33 Spanish cities

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    Background: In Spain, several ecological studies have analyzed trends in socioeconomic inequalities in mortality from all causes in urban areas over time. However, the results of these studies are quite heterogeneous finding, in general, that inequalities decreased, or remained stable. Therefore, the objectives of this study are: (1) to identify trends in geographical inequalities in all-cause mortality in the census tracts of 33 Spanish cities between the two periods 1996–1998 and 2005–2007; (2) to analyse trends in the relationship between these geographical inequalities and socioeconomic deprivation; and (3) to obtain an overall measure which summarises the relationship found in each one of the cities and to analyse its variation over time.Methods: Ecological study of trends with 2 cross-sectional cuts, corresponding to two periods of analysis: 1996–1998 and 2005–2007. Units of analysis were census tracts of the 33 Spanish cities. A deprivation index calculated for each census tracts in all cities was included as a covariate. A Bayesian hierarchical model was used to estimate smoothed Standardized Mortality Ratios (sSMR) by each census tract and period. The geographical distribution of these sSMR was represented using maps of septiles. In addition, two different Bayesian hierarchical models were used to measure the association between all-cause mortality and the deprivation index in each city and period, and by sex: (1) including the association as a fixed effect for each city; (2) including the association as random effects. In both models the data spatial structure can be controlled within each city. The association in each city was measured using relative risks (RR) and their 95 % credible intervals (95 % CI).Results: For most cities and in both sexes, mortality rates decline over time. For women, the mortality and deprivation patterns are similar in the first period, while in the second they are different for most cities. For men, RRs remain stable over time in 29 cities, in 3 diminish and in 1 increase. For women, in 30 cities, a non-significant change over time in RR is observed. However, in 4 cities RR diminishes. In overall terms, inequalities decrease (with a probability of 0.9) in both men (RR¿=¿1.13, 95 % CI¿=¿1.12–1.15 in the 1st period; RR¿=¿1.11, 95 % CI¿=¿1.09–1.13 in the 2nd period) and women (RR¿=¿1.07, 95 % CI¿=¿1.05–1.08 in the 1st period; RR¿=¿1.04, 95 % CI¿=¿1.02–1.06 in the 2nd period).Conclusions: In the future, it is important to conduct further trend studies, allowing to monitoring trends in socioeconomic inequalities in mortality and to identify (among other things) temporal factors that may influence these inequalities
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