369 research outputs found

    Structural, Optical and Electrochromic Properties of Sol–Gel V

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    Vanadium pentoxide thin films are prepared by the sol–gel route by dissolving V2O5 powder (99.5% purity) in H2O2 solution. The solution is spin-coated on glass substrates for optical (UV–VIS–NIR) and XRD analysis, and on ITOcoated glass substrates for electrochromic measurements. The samples are then annealed at 150°C for 1 hour. The resulting films have a yellow-orange color, typical of polycrystalline V2O5. XRD measurements have shown that after annealing in air at 400°C the structure of the films has a c-axis preferred orientation, the (0 0 1)-type planes lying parallel to the substrate. SEM analysis revealed a smooth surface. The films’ optical and physical constants (n, α, Eg, the thickness d and the mean thickness inhomogeneity s) are calculated using a simple and accurate method based on the transmission spectrum alone. The films’ electrochromism is studied using cyclic voltammetry (CV) and chronoamperometry in propylene carbonate solution containing 1 mol/l LiCIO4. The films show reversible multichromism (yellow–green–blue) upon Li+ ion insertion/extraction. The absorbance of films colored at three different potentials is measured in the UV–VIS–PIR wavelength range, and this study shows that the changes in the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works

    Diurnal cycle of precipitable water vapor over Spain

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    Knowledge of the diurnal cycle of precipitable water vapor (PWV) is very limited owing to the lack of data with sufficient temporal resolution. Currently, GPS receivers have proven to be a suitable technique to determine PWV diurnal variations. In this study, the annual and seasonal diurnal cycles of PWV have been obtained from GPS data for 10 locations over Spain. The minimum value of PWV is reached approximately at the same time at all the stations, ∼0430–0530 UTC, whereas the maximum is reached in the second half of the day, but with a larger dispersion of its occurrence between stations. The annual sub-daily variability ranges from 0.41 to 1.35 mm (3–7%). The highest values are recorded at the stations on the Mediterranean coast, with a doubling of the values of the stations on the Atlantic coast or inland. The winter cycle is quite similar at all locations, whereas in summer local effects are felt strongly, making the diurnal cycle quite different between stations. The PWV mean diurnal cycle is strongest in summer and weakest in spring, with a sub-daily variability of 1.34 and 0.66 mm respectively. Harmonic analysis shows that the first two harmonics can explain 97% of the variance. The diurnal (24 h) harmonic explains 85% of the variance, has mean amplitude of 0.40 mm, and the peak time is from early afternoon to evening. The semi-diurnal (12 h) harmonic is weaker, with an amplitude of 0.13 mm, and peak time between 0400 and 1000 UTC. The diurnal cycle of temperature alone would be a proxy for PWV cycle during the night, but not during the daytime. The breeze regime is the main factor responsible for the phase lag between PWV and temperature cycles during daytime. No clear correlation between the daily cycle of precipitation and PWV has been found

    Breakdown of Conformal Invariance at Strongly Random Critical Points

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    We consider the breakdown of conformal and scale invariance in random systems with strongly random critical points. Extending previous results on one-dimensional systems, we provide an example of a three-dimensional system which has a strongly random critical point. The average correlation functions of this system demonstrate a breakdown of conformal invariance, while the typical correlation functions demonstrate a breakdown of scale invariance. The breakdown of conformal invariance is due to the vanishing of the correlation functions at the infinite disorder fixed point, causing the critical correlation functions to be controlled by a dangerously irrelevant operator describing the approach to the fixed point. We relate the computation of average correlation functions to a problem of persistence in the RG flow.Comment: 9 page

    Cost-Effectiveness of Web-Based Patient-Reported Outcome Surveillance in Patients With Lung Cancer

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    INTRODUCTION: A multicenter randomized clinical trial in France found an overall survival benefit of web-based patient-reported outcome (PRO)-based surveillance after initial treatment for lung cancer compared with conventional surveillance. The aim of this study was to assess the cost-effectiveness of this PRO-based surveillance in lung cancer patients. METHODS: This medico-economic analysis used data from the clinical trial, augmented by abstracted chart data and costs of consultations, imaging, transportations, information technology, and treatments. Costs were calculated based on actual reimbursement rates in France, and health utilities were estimated based on scientific literature review. Willingness-to-pay thresholds of €30,000 per quality-adjusted life year (QALY) and €90,000 per QALY were used to define a very cost-effective and cost-effective strategy, respectively. Average annual costs of experimental and control surveillance approaches were calculated. The incremental cost-effectiveness ratio was expressed as cost per life-year gained and QALY gained, from the health insurance payer perspective. One-way and multivariate probabilistic sensitivity analyses were performed. RESULTS: Average annual cost of surveillance follow-up was €362 lower per patient in the PRO arm (€941/year/patient) compared to control (€1,304/year/patient). The PRO approach presented an incremental cost-effectiveness ratio of €12,127 per life-year gained and €20,912 per QALY gained. The probabilities that the experimental strategy is very cost-effective and cost-effective were 97% and 100%, respectively. CONCLUSIONS: Surveillance of lung cancer patients using web-based PRO reduced the follow-up costs. Compared to conventional monitoring, this surveillance modality represents a cost-effective strategy and should be considered in cancer care delivery

    Study on the influence of different error sources on sky radiance measurements and inversion-derived aerosol products in the frame of AERONET

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    Comunicación presentada en: 2012 European Aerosol Conference (EAC-2012), B-WG01S2P30, celebrada del 2 al 7 de septiembre de 2012 en Granada.Financial support from the Spanish MICINN under projects with ref. CGL2009-09740, CGL2011-23413, CGL2010-09480-E and CGL2011-13085-E is gratefully acknowledged

    Pointing error and field of view of AERONET CIMEL-318 sun photometers

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    Resumen de la comunicación oral presentada en: 1st Iberian Meeting on Aerosol Science and Technology – RICTA 2013, celebrado del 1 al 3 de julio de 2013 en Évora, Portugal
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