380 research outputs found

    Analysis of Bi Distribution in Epitaxial GaAsBi by aberration-corrected HAADF-STEM

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    The Bi content in GaAs/GaAs1 − xBix/GaAs heterostructures grown by molecular beam epitaxy at a substrate temperature close to 340 °C is investigated by aberration-corrected high-angle annular dark-field techniques. The analysis at low magnification of high-angle annular dark-field scanning transmission electron microscopy images, corroborated by EDX analysis, revealed planar defect-free layers and a non-homogeneous Bi distribution at the interfaces and within the GaAsBi layer. At high magnification, the qHAADF analysis confirmed the inhomogeneous distribution and Bi segregation at the GaAsBi/GaAs interface at low Bi flux and distorted dumbbell shape in areas with higher Bi content. At higher Bi flux, the size of the Bi gathering increases leading to roughly equiaxial Bi-rich particles faceted along zinc blende {111} and uniformly dispersed around the matrix and interfaces. FFT analysis checks the coexistence of two phases in some clusters: a rhombohedral pure Bi (rh-Bi) one surrounded by a zinc blende GaAs1 − xBix matrix. Clusters may be affecting to the local lattice relaxation and leading to a partially relaxed GaAsBi/GaAs system, in good agreement with XRD analysis

    In Dominici Bannes nonnullas propositiones quae in eius Commentariis in Primam Partem et in 2am. 2ae. Sancti Thomae notata sunt, censura

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    Incipit: "Illmis. et Rmis DD. cardinalibus Congregationis Sancti Officii Inquisitiones. Non dolore aliquo animi commotus, quod mea doctrina sit a R.P. Domenico Bañes antea reprehensa, atque ad hoc Sanctum Tribunal delata, nonnulla de multis, quae in eius Commentariis theologicis animadversione digna esse censui..." (fol. 41r)Explicit: "... praesertim ex Concilio Calcedonensi, cn. 9; Agatensi, cn. 32; Carthagenensi, Toletano et aliis, et ex decretis Summorum Pontificum Caii, Marcelline et Gregorii, quem errorem contentum in illis Bañes propositionibus perspicue refellunt" (fol. 81v)30792E-1 T-5 N-1

    Quid senserit D. Ludovicus Molina in materia de auxiliis, quae inter PP. Dominicanos et Jesuitas controvertitur

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    Incipit: "Primo, Molina contra Pelagium, necessitatem gratiae simpliciter constituit et late probat esse de fide, disp. 6, art. 13, quaestionis 14, pag. 24..." (fol. 113bis)Explicit: "... Ex his omnibus aperte colligitur propositiones contra Molinam exhibitas Sti. Vtrae. tanquam pelagianas aut semipelagianas, vel meras esse calumnias vel hominum qui aut eius doctrinam non legerunt aut qui fuering Pelagii aut semipelagianorum errores ignorarunt" (fol. 114v)30792E-1 T-5 N-1

    Cubic and hexagonal InGaAsN dilute arsenides by unintentional homogeneous incorporation of As into InGaN

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    Arsenic alloying is observed for epitaxial layers nominally intended to be In0.75Ga0.25N. Voids form beneath their interfaces with GaAs substrates, acting as sources of Ga + As out-diffusion into the growing epilayers. As a result, heteroepitaxial single-phase quaternary InxGa1-xAsyN1-y, films are formed with x similar to 0.55 and 0.05 menor que y menor que 0,10. While an undoped epilayer retains the wurtzite structure, a Mn-doped sample showed randomly spaced dopant segregations, which, together with a slightly higher As concentration, led to a transformation from the hexagonal to the twinned cubic phase

    Influence of the AlN interlayer thickness on the photovoltaic properties of in-rich AlInN on Si heterojunctions deposited by RF sputtering

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    8 pags., 5 figs., 1 tab.We report the influence of the AlN interlayer thickness (0-15 nm) on the photovoltaic properties of AlInN on Si heterojunction solar cells deposited by radio frequency sputtering. The poor junction band alignment and the presence of a 2-3 nm thick amorphous layer at the interface mitigates the response in devices fabricated by direct deposition of n-AlInN on p-Si(111). Adding a 4-nm-thick AlN buffer layer improves the AlInN crystalline quality and the interface alignment leading to devices with a conversion efficiency of 1.5% under 1-sun AM1.5G illumination. For thicker buffers the performance lessens due to inefficient tunnel transport through the AlN. These results demonstrate the feasibility of using In-rich AlInN alloys deposited by radio frequency sputtering as novel electron-selective contacts to Si-heterojunction solar cells.Support from projects NitPho (TEC2014-60483-R), ANOMALOS (TEC2015- 71127-C2-2-R), INFRASIL (TEC 2013-41730-R), SINFOTON (S2013/MIT 2790), MADRID-PV (2013/MAE-2780), PhotoAl (CCG2015/EXP-014), PAI research group (TEP-946 INNANOMAT), and FEDER-EU is acknowledged. TEM data were taken at DME-SC-ICyT-UCA. A. Nuñez- ˜ Cascajero thanks her grant to the University of Alcala and D. Montero acknowledges his contract ´ BES-2014-067585

    Borrador de súplica al Papa

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    Incipit: "Beatissime Pater. Sententiam Patrum Societatis Iesu de gratia et libero arbitrio quam plerique Dominicanae familiae Patres in controversiam vocant ab ea plurimum abesse quae inter ipsos et doctorem Ludovicum Molinam agitata in Hispania est..." (fol. 115r)Explicit: "... confutandam aptissimam atque hisce temporibus maxime necessariam proxime ad Deum accedit autoritate pronuntiet, et cui haec et omnia nostra semper subiecta volumus" (fol. 123v)30792E-1 T-5 N-1

    Estudio de fractura de estructuras reticulares de termoplásticos fabricadas mediante modelado por deposición fundida

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    Las estructuras reticulares están presentando un auge especial, principalmente ligado al uso cada vez más extendido de equipos comerciales de fabricación aditiva o impresión 3D. Estas estructuras, utilizadas en planchas o perfiles, presentan una excelente rigidez a la vez que se maximiza la liviandad. El presente trabajo consiste en un estudio de la evolución de la fractura de paneles sándwich con núcleo de estructura reticular, cuando son sometidos a esfuerzos de compresión y de flexión. Se ha considerado el uso de retículas de tipo de celda abierta y de celda cerrada, fabricadas en ABS y PC mediante modelado por deposición fundida (FDM del inglés Fused Deposition Modelling). Se estudia la evolución de la fractura mediante grabación en vídeo con cámaras HD, que adquieren video desde dos direcciones de forma simultánea en el transcurso de ensayos de compresión y flexión a tres puntos. Aunque la evolución teórica de la fractura de este tipo de estructuras es ya conocida, el proceso de fabricación FDM introduce ciertas peculiaridades que son las que se esperan extraer tras este estudio.Los autores agradecen a la División de Fabricación Aditiva de los Servicios Centrales de Investigación Científica y Tecnológica de la Universidad de Cádiz, al MINECO (proyecto TEC2017-86102-C2- 2-R), y a la Junta de Andalucía (grupo de investigación PAI TEP-946 INNANOMAT)

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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