492 research outputs found

    Improved photoenergy properties of low-emissivity coatings deposited by sputtering with an ion gun treatment

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    This work studies the effect of ion treatment on low-emissivity (low-e) coatings deposited by magnetron sputtering. Specifically, we have investigated the application of an ion treatment in the dielectric layer before deposition of a layer of silver. This reduces layer roughness which means the silver layer can be deposited with enhanced characteristics. We have also evaluated the etching rate on the SnOx layer due to the ion treatment on already deposit coatings of equal thicknesses. Subsequently, we studied the effects on the coating's photoenergy properties. For equivalent coatings, we found that those treated with ions were more transparent in the visible region, more reflective, and had a lower emissivity, which are essential requirements for low-e coatings applied in architectural glass

    Monitorización de parámetros de calidad de redes de transmisión mediante alta resolución espectral en dominio óptico

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    La creciente demanda de mayor ancho de banda en los sistemas de comunicación globales exige una arquitectura cada vez mas compleja donde toman fuerza aquellas redes en las cuales se prescinde de puntos de regeneración intermedios. Los sistemas con multiplexación densa en longitud de onda (DWDM) de camino reconfigurable exigen una revisión de los estándares de medida de parámetros de calidad como la dispersión del modo de polarización (PMD) o la relación señal a ruido óptica (OSNR). Se describen en este trabajo las posibilidades que ofrece el análisis de espectros mediante difusión Brillouin estimulada para la monitorización de PMD y OSNR frente a métodos convencionales. El uso de la difusión Brillouin estimulada como filtro en un analizador de espectros ópticos permite obtener valores de densidad de potencia en intervalos espectrales suficientemente estrechos como para no verse alterados por la proximidad entre canales. El análisis espectral de alta resolución introduce mejoras significativas en los métodos de medida de OSNR basados en la supresión de señal por polarización, al hacerlos compatibles con variaciones del estado de polarización a lo largo del ancho de banda de la señal. Además, la coherencia intrínseca del efecto de dispersión Brillouin permite monitorizar diferencias en estado de polarización entre componentes espectrales de la señal, y caracterizar de esta manera en dominio óptico la degradación por PMD presente en cada uno de los canales de una señal problema sin necesidad de recurrir a métodos en detección como el diagrama de ojo o la tasa de error de bit

    Different Coordination Modes of a Tripod Phosphine in Gold(I) and Silver(I) Complexes

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    The following gold(I) and silver(I) complexes of the tritertiary phosphine 1,1,1- tris(diphenylphosphinomethyl)ethane, tripod , have been synthesised: Au3(tripod)X3 [X = Cl(1), Br(2), I(3)]; [Au3(tripod)2Cl2]Cl (4); Au(tripod)X [X = Br(5), I(6)]; Ag3(tripod) (NO3)4 (7), Ag(tripod)NO3 (8). They were characterized by X-ray diffraction (complexes 2, 3 and 4), 31P NMR spectroscopy, electrospray and FAB mass spectrometry and infrared spectroscopy. Complexes 2 and 3 show a linear coordination geometry for Au(I), with relatively short Au-P bond distances. Complex 3 has a Au•••Au intramolecular distance of 3.326 A ° , while complex 2 had a short Au•••Au intermolecular interaction of 3.048 A ° . Complexes 4-6 were found by 31P NMR spectroscopy studies to contain a mixture of species in solution, one of which crystallised as [Au3(tripod|)2Cl2]Cl which was shown by X-ray diffraction to contain both tetrahedral and linear Au(I), the first example of a Au(I) complex containing such a mixture of geometries. The reaction of [Au3 (tripod)Cl3] (1) with tripod led successfully to the formation of [Au3(tripod|)2Cl2]+ and [Au3(tripod)2Cl3]+ and [Au3(tripod|)3Cl]2+. The silver(I) complexes, 7 and 8 appear to contain linear and tetrahedral Ag(I), respectively

    Genomic Evaluation for a Crossbreeding System Implementing Breed-of-Origin for Targeted Markers

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    The genome in crossbred animals is a mosaic of genomic regions inherited from the different parental breeds. We previously showed that effects of haplotypes strongly associated with crossbred performance are different depending upon from which parental breed they are inherited, however, the majority of the genomic regions are not or only weakly associated with crossbred performance. Therefore, our objective was to develop a model that distinguishes between selected single nucleotide polymorphisms (SNP) strongly associated with crossbred performance and all remaining SNP. For the selected SNP, breed-specific allele effects were fitted whereas for the remaining SNP it was assumed that effects are the same across breeds (SEL-BOA model). We used data from three purebred populations; S, LR, and LW, and the corresponding crossbred population. We selected SNP that explained together either 5 or 10% of the total crossbred genetic variance for average daily gain in each breed of origin. The model was compared to a model where all SNP-alleles were allowed to have different effects for crossbred performance depending upon the breed of origin (BOA model) and to a model where all SNP-alleles had the same effect for crossbred performance across breeds (G model). Across the models, the heritability for crossbred performance was very similar with values of 0.29–0.30. With the SEL-BOA models, in general, the purebred-crossbred genetic correlation (rpc) for the selected SNP was larger than for the non-selected SNP. For breed LR, the rpc for selected SNP and non-selected SNP estimated with the SEL-BOA 5% and SEL-BOA 10% were very different compared to the rpc estimated with the G or BOA model. For breeds S and LW, there was not a big discrepancy for the rpc estimated with the SEL-BOA models and with the G or BOA model. The BOA model calculates more accurate breeding values of purebred animals for crossbred performance than the G model when rpc differs (≈10%) between the G and the BOA model. Superiority of the SEL-BOA model compared to the BOA model was only observed for SEL-BOA 10% and when rpc for the selected and non-selected SNP differed both (≈20%) from the rpc estimated by the G or BOA model

    Intermittent dislocation flow in viscoplastic deformation

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    The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated `dislocation-dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report acoustic emission measurements on stressed ice single crystals, the results of which indicate that dislocations move in a scale-free intermittent fashion. This result is confirmed by numerical simulations of a model of interacting dislocations that successfully reproduces the main features of the experiment. We find that dislocations generate a slowly evolving configuration landscape which coexists with rapid collective rearrangements. These rearrangements involve a comparatively small fraction of the dislocations and lead to an intermittent behavior of the net plastic response. This basic dynamical picture appears to be a generic feature in the deformation of many other materials. Moreover, it should provide a framework for discussing fundamental aspects of plasticity, that goes beyond standard mean-field approaches that see plastic deformation as a smooth laminar flow

    The Influence of B Cell Depletion Therapy on Naturally Acquired Immunity to Streptococcus pneumoniae

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    The anti-CD20 antibody Rituximab to deplete CD20+ B cells is an effective treatment for rheumatoid arthritis and B cell malignancies, but is associated with an increased incidence of respiratory infections. Using mouse models we have investigated the consequences of B cell depletion on natural and acquired humoral immunity to Streptococcus pneumoniae. B cell depletion of naïve C57Bl/6 mice reduced natural IgM recognition of S. pneumoniae, but did not increase susceptibility to S. pneumoniae pneumonia. ELISA and flow cytometry assays demonstrated significantly reduced IgG and IgM recognition of S. pneumoniae in sera from mice treated with B cell depletion prior to S. pneumoniae nasopharyngeal colonization compared to untreated mice. Colonization induced antibody responses to protein rather than capsular antigen, and when measured using a protein array B cell depletion prior to colonization reduced serum levels of IgG to several protein antigens. However, B cell depleted S. pneumoniae colonized mice were still partially protected against both lung infection and septicemia when challenged with S. pneumoniae after reconstitution of their B cells. These data indicate that although B cell depletion markedly impairs antibody recognition of S. pneumoniae in colonized mice, some protective immunity is maintained, perhaps mediated by cellular immunity

    Fabrication and characterization of Y₂O₃ dispersion strengthened copper alloys

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    Part of special issue: Proceedings of the 16th International Conference on Fusion Reactor Materials (ICFRM-16).Three copper base materials were fabricated following different routes: cast Cu–1 wt.%Y (C-Cu1Y) produced by vacuum induction melting, and Cu–1 wt.%Y (PM-Cu1Y) and Cu–1 wt.%Y2O3 (PM-Cu1Y2O3) both processed by a powder metallurgy route and sintering by hot isostatic pressing. PM-Cu1Y alloy was prepared by cryomilling and PM-Cu1Y2O3 by conventional milling at room temperature. The materials were characterized by X-ray diffraction, optical and electron microscopy and microhardness measurements. C-Cu1Y presents a characteristic eutectic microstructure while PM-Cu1Y2O3 exhibits a composite like microstructure. Electron microscopy analyses of as-HIP PM-Cu1Y revealed irregular decoration of yttrium-rich oxides at the grain boundaries and an inhomogeneous dispersion of polygonal shaped yttrium-rich oxides dispersed in the Cu matrix. Tensile tests performed on PM-Cu–1Y on the temperature range of 293–773 K have showed a decrease of the yield strength at temperatures higher than 473 K, and monotonically decrease of the ultimate tensile strength and maximum plastic strain on increasing temperature.This research has been supported by Ministerio de Economía y Competitividad of Spain (ENE2012-39787-C06-05). The financial support from the Comunidad de Madrid, through the programs TECHNOFUSION (S2009/ENE-1679) and ESTRUMAT (CM S2009MAT-1585), and the additional subvention from EURATOM/CIEMAT association through contract EFDA (WP12-MAT-HHFMAM-02) are also gratefully acknowledged.Publicad

    Enantioselective adsorption of ibuprofen and lysine in metal-organic frameworks

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    This study reveals the efficient enantiomeric separation of bioactive molecules in the liquid phase. Chiral structure HMOF-1 separates racemic mixtures whereas heteroselectivity is observed for scalemic mixtures of ibuprofen using non-chiral MIL-47 and MIL-53. Lysine enantiomers are only separated by HMOF-1. These separations are controlled by the tight confinement of the molecules

    Anisotropy in mechanical properties and fracture behavior of an oxide dispersion Fe20Cr5Al alloy

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    Anisotropy of fracture toughness and fracture behavior of Fe20Cr5Al oxide dispersion-strengthened alloy has been investigated by means of compression tests, hardness tests, and wedge splitting test. The results show a small effect of the compression direction on yield strength (YS) and strain hardening. The YS is minimum for longitudinal direction and maximum for the tangential direction. The transverse plastic strain ratio is similar for tangential and longitudinal directions but very different from that in normal direction. Hardness depends on the indentation plane; it is lower for any plane parallel to the L-T plane and of similar magnitude for the other orthogonal planes, i.e., the L-S and T-S planes. Macroscopically, two failure modes have been observed after wedge-splitting tests, those of LS and TS specimens in which fracture deviates along one or two branches normal to the notch plane, and those of LT, TL, SL, and ST specimens in which fracture propagates along the notch plane. Besides LT and TL specimens present delaminations parallel to L-T plane. Both, the fracture surface of branching cracks and that of the delaminations, show an intergranular brittle fracture appearance. It is proposed that the main cause of the delamination and crack branching is the alignment in the mesoscopic scale of the ultrafine grains structure which is enhanced by the 〈110〉- texture of the material and by the presence in the grain boundaries of both yttria dispersoids and impurity contaminations. An elastoplastic finite element analysis was performed to study what stress state is the cause of the branches and delaminations. It is concluded that the normal to the crack branches and/or the shear stress components could determine the crack bifurcation mechanism, whereas the delamination it seems that it is controlled by the magnitude of the stress component normal to the delamination plane. © The Minerals, Metals & Materials Society and ASM International 2014.Peer Reviewe
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