508 research outputs found
Laser treatment of nanoparticulated metal thin films for ceramic tile decoration
This paper presents a new method for the fabrication of metal-like decorative layers on glazed ceramic tiles. It consists of the laser treatment of copper thin films prepared by electron beam evaporation at glancing angles. A thin film of discontinuous copper nanoparticles was electron beam evaporated in an oblique angle configuration onto ceramic tiles and an ample palette of colors obtained by laser treatment both in air and in vacuum. Scanning electron microscopy (SEM and FESEM) along with UV-vis-NIR spectroscopy and time of flight secondary ion mass spectrometry (TOF-SIMS) analysis were used to characterize the differently colored layers. Based on these analyses, color development has been accounted for by a simple model considering surface melting phenomena and different microstructural and chemical transformations of the outmost surface layers of samples.Financial support from the EU (Grant LIFE11/ENV/ES560),
Innovaragon (Grant ITA-DGA/ES 1368), DGA (Group T87),
MINECO (Projects MAT2013-40852-R and MAT2013-42900-P), and Junta de Andalucia (Projects TEP 8067 and FQM 6900) is gratefully acknowledged. F.R.-G. acknowledges the
Portuguese Science and Technology Foundation for Grant
SFRH/BPD/108581/2015.Peer reviewe
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Representativity error for temperature and humidity using the Met Office high-resolution model
The observation-error covariance matrix used in data assimilation contains contributions from instrument errors, representativity errors and errors introduced by the approximated observation operator. Forward model errors arise when the observation operator does not correctly model the observations or when observations can resolve spatial scales that the model cannot. Previous work to estimate the observation-error covariance matrix for particular observing instruments has shown that it contains signifcant correlations. In particular, correlations for humidity data are more significant than those for temperature. However it is not known what proportion of these correlations can be attributed to the representativity errors. In this article we apply an existing method for calculating representativity error, previously applied to an idealised system, to NWP data. We calculate horizontal errors of representativity for temperature and humidity using data from the Met Office high-resolution UK variable resolution model. Our results show that errors of representativity are correlated and more significant for specific humidity than temperature. We also find that representativity error varies with height. This suggests that the assimilation scheme may be improved if these errors are explicitly included in a data assimilation scheme.
This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland
Una descripción distinta de la orientación en las lenguas de signos
Sign languages are a very interesting object of linguistic study, posing challenges not present in oral languages. One of these challenges is describing and transcribing the internal structure of the language in a way that is adequate to its characteristics but also compatible with existing linguistic practice. The phonology of sign languages is of special interest. We focus on one phonological feature: that of hand orientation. We propose an interpretation and description system that better captures underlying meaning and structure, and that is more appropriate for its formal and computational treatment.Las lenguas de signos son un objeto de estudio lingüístico de gran interés. Presentan retos y dificultades distintos a los de las lenguas orales, como describir y transcribir la estructura interna de la lengua de una manera adecuada a sus características únicas pero también compatible con la práctica lingüística actual. El caso de la fonología es especialmente interesante. Nos centramos en un rasgo fonológico concreto: la orientación de la mano. Proponemos una interpretación y un sistema de descripción que capturan mejor la semántica y la estructura subyacente, y que además permiten un tratamiento formal y computacional más adecuado.This research is partially supported by the IDiLyCo project (TIN2015-66655-R) funded by the Spanish Ministry of Economy, Industry and Competitiveness
4D-Var Assimilation of MIPAS chemical observations: ozone and nitrogen dioxide analyses
International audienceThis paper discusses the global analyses of stratospheric ozone (O3) and nitrogen dioxide (NO2) obtained by the Belgian Assimilation System for Chemical Observations from Envisat (BASCOE). Based on a chemistry transport model (CTM) and the 4-dimensional variational (4D-Var) method, BASCOE has assimilated chemical observations of O3, NO2, HNO3, N2O, CH4 and H2O, made between July 2002 and March 2004 by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the European Space Agency (ESA) Environment Satellite (ENVISAT). This corresponds to the entire period during which MIPAS was operating at its nominal resolution. Our analyses are evaluated against assimilated MIPAS data and independent HALOE (HALogen Occultation Experiment) and POAM-III (Polar Ozone and Aerosol Measurement) satellite data. A good agreement is generally found between the analyses and these datasets, in both cases within the estimated error bars of the observations. The benefit of data assimilation is also evaluated using a BASCOE free model run. For O3, the gain from the assimilation is significant during ozone hole conditions, and in the lower stratosphere. Elsewhere, the free model run is within the MIPAS uncertainties and the assimilation does not provide significant improvement. For NO2, the gain from the assimilation is realized through most of the stratosphere. Using the BASCOE analyses, we estimate the differences between MIPAS data and independent data from HALOE and POAM-III, and find results close to those obtained by classical validation methods involving only direct measurement-to-measurement comparisons. Our results extend and reinforce previous MIPAS data validation efforts by taking account of a much larger variety of atmospheric states and measurement conditions. This study discusses possible further developments of the BASCOE data assimilation system; these concern the horizontal resolution, a better filtering of NO2 observations, and the photolysis calculation near the lid of the model. The ozone analyses are publicly available via the PROMOTE project http://www.gse-promote.org)
Portable IR dye laser optofluidic microresonator as a temperature and chemical sensor
A compact and portable optofluidic microresonator has been fabricated and characterized. It is based on a Fabry-Perot microcavity consisting essentially of two tailored dichroic Bragg mirrors prepared by reactive magnetron sputtering deposition. The microresonator has been filled with an ethanol solution of Nile-Blue dye. Infrared laser emission has been measured with a pump threshold as low as 0.12 MW/cm2 and an external energy conversion efficiency of 41%. The application of the device as a temperature and a chemical sensor is demonstrated. Small temperature variations as well as small amount of water concentrations in the liquid laser medium are detected as a shift of the resonant laser modes.España Mineco MAT2013-40852-R MAT2013-46649-C4-4-PMALTA CSD2007-0045FUNCOAT MAT2015-69035-REDCEU-FEDER P12- FQM-2265 P10-FQM-690
The anions [Cptt2Zr(μ-S)2M(CO)2]- (M = Rh, Ir) as versatile precursors for the synthesis of sulfido-bridged early−late heterotrimetallic (ELHT) compounds
The reaction of [Cp2 ttZr(μ3-S) 2{Ir(CO)2}2] (Cptt = η5-1,3-di-tert-butylcyclopentadienyl) with dppe (1,2-bis-(diphenylphosphino)ethane) affords the ion-pair compound [Ir(CO)(dPPe)2][Cp2 ttZr(μ-S) 2Ir(CO)2] (2). The related compound [Rh(dPPe) 2][Cp2 ttZr(μ-S)2Rh(CO) 2] (5) has been obtained in solution under a carbon monoxide atmosphere by reaction of [Cp2 ttZr(μ3-S) 2{Rh(CO)2}2] with dppe through the intermediate heterotrinuclear compound [Cp2 ttZr(μ3-S) 2{Rh(dppe)}{Rh(CO)2}] (4). Reaction of the heterodinuclear anion [Cp2 ttZr(μ-S)2Ir(CO) 2]-, generated in situ, with [Rh(μ-Cl)(cod)] 2, [RhCl2(CO)2]- and [Pd(μ-Cl)-(η3-C3H5)]2 affords the d0-d8-d8 early-late compounds [Cp 2 ttZr(μ3-S)2{Ir(CO) 2}{Rh(cod)}] (6), [Cp2 tt-Zr(μ3-S) 2{Ir(CO)2}{Rh(CO)2}] (7), and [Cp 2 ttZr(μ3-S)2{Ir(CO) 2}{Pd(η3-C3H5)}] (8) each with a symmetrical trigonal-bipyramidal M3(μ3-S)2 heterotrimetallic metal-sulfur core. In the same way, the reaction of [Cp 2 ttZr(μ-S)2M(CO)2]- (M = Rh, Ir) with [AuCl(PPh3)] leads to the preparation of the d 0-d8-d10 early-late compounds [Cp 2 ttZr(μ-S)2(Ir(CO)2}{Au(PPh 3)}] (9) and [Cp2 ttZr(μ-S) 2{Rh(CO)2}{Au(PPh3)}] (10) with an open M 3(μ3-S)(μ2-S) heterotrimetallic metal-sulfur framework. On the other hand, treatment of the bis(hydrosulfido) zirconium compound [Cp2 ttZr(SH)2] with triethylamine followed by addition of [Pd(μ-Cl)(η3-C 3H5)]2 or [AuCl(PPh3)] affords the sulfido-bridged early-late heterobimetallic compounds [Cp2 ttZr(μ3-S)2{Pd(η3-C 3H5)}2] (11) and [Cp2 ttZr(μ-S)2(Au(PPh3)}2] (12). The molecular structure of complexes 9 and 12 determined by X-ray diffraction methods are also described.The financial support from Ministerio de Educación y Ciencia (MEC/FEDER) is gratefully acknowledged (Projects CTQ2006-03973/BQU and Factoría de Cristalización, CONSOLIDER INGENIO-2010).Peer Reviewe
Zidovudine in persons with asympomatic HIV infection and CD4+ cell counts greater than 400 per cubic millimeter
Study of the effectiveness of some chelant agents for the remediation of the mercury contaminated soil from almaden
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