1,891 research outputs found

    Electron-phonon coupling in potassium-doped graphene: Angle-resolved photoemission spectroscopy

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    The electron-phonon coupling in potassium-doped graphene on Ir(111) is studied via the renormalization of the pi* band near the Fermi level, using angle-resolved photoemission spectroscopy. The renormalization is found to be fairly weak and almost isotropic, with a mass enhancement parameter of lambda= 0.28(6) for both the K-M and the K-G direction. These results are found to agree well with recent first principles calculations.Comment: 5 pages, 3 figure

    Isoprenoid emission in trees of Quercus pubescens and Quercus ilex with lifetime exposure to naturally high CO2 environment

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    The long-term effect of elevated atmospheric CO2 on isoprenoid emissions from adult trees of two Mediterranean oak species (the monoterpene-emitting Quercus ilex L. and the isoprene-emitting Quercus pubescens Willd.) native to a high-CO2 environment was investigated. During two consecutive years, isoprenoid emission was monitored both at branch level, measuring the actual emissions under natural conditions, and at leaf level, measuring the basal emissions under the standard conditions of 30 degreesC and at light intensity of 1000 mumol m(-2) s(-1). Long-term exposure to high atmospheric levels of CO2 did not significantly affect the actual isoprenoid emissions. However, when leaves of plants grown in the control site were exposed for a short period to an elevated CO2 level by rapidly switching the CO2 concentration in the gas-exchange cuvette, both isoprene and monoterpene basal emissions were clearly inhibited. These results generally confirm the inhibitory effect of elevated CO2 on isoprenoid emission. The absence of a CO2 effect on actual emissions might indicate higher leaf temperature at elevated CO2, or an interaction with multiple stresses some of which (e.g. recurrent droughts) may compensate for the CO2 effect in Mediterranean ecosystems. Under elevated CO2, isoprene emission by Q. pubescens was also uncoupled from the previous day\u27s air temperature. In addition, pronounced daily and seasonal variations of basal emission were observed under elevated CO2 underlining that correction factors may be necessary to improve the realistic estimation of isoprene emissions with empirical algorithms in the future. A positive linear correlation of isoprenoid emission with the photosynthetic electron transport and in particular with its calculated fraction used for isoprenoid synthesis was found. The slope of this relationship was different for isoprene and monoterpenes, but did not change when plants were grown in either ambient or elevated CO2. This suggests that physiological algorithms may usefully predict isoprenoid emission also under rising CO2 levels

    SIGNAL GROUPING FOR CONDITION MONITORING OF NUCLEAR POWER PLANT COMPONENTS

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    International audienceThe present work investigates the possibility of building a condition monitoring model by splitting the usually very large number of signals measured by the sensors into subgroups and building a specialized model for each subgroup. Different criteria are considered for selecting the signal groups, such as the location of the measurements (i.e., signals measured in the same area of the plant belong to the same group) and their correlation (i.e., correlated signals are grouped together). A real case study concerning 48 signals selected between those used to monitor the reactor coolant pump of a Pressurized Water Reactor (PWR) is considered in order to verify the monitoring performance of different grouping criteria. Performance metrics measuring accuracy, robustness and spill-over effect have been considered in the evaluation. Key Words: Condition Monitoring, Empirical Modeling, Power Plants, Safety Critical Nuclear Instrumentation, Autoassociative models

    Management of Post-Harvest Anthracnose: Current Approaches and Future Perspectives

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    Anthracnose is a severe disease caused by Colletotrichum spp. on several crop species. Fungal infections can occur both in the field and at the post-harvest stage causing severe lesions on fruits and economic losses. Physical treatments and synthetic fungicides have traditionally been the preferred means to control anthracnose adverse effects; however, the urgent need to decrease the use of toxic chemicals led to the investigation of innovative and sustainable protection techniques. Evidence for the efficacy of biological agents and vegetal derivates has been reported; however, their introduction into actual crop protection strategies requires the solutions of several critical issues. Biotechnology-based approaches have also been explored, revealing the opportunity to develop innovative and safe methods for anthracnose management through genome editing and RNA interference technologies. Nevertheless, besides the number of advantages related to their use, e.g., the putative absence of adverse effects due to their high specificity, a number of aspects remain to be clarified to enable their introduction into Integrated Pest Management (IPM) protocols against Colletotrichum spp. disease

    Predicting human eye fixations via an LSTM-Based saliency attentive model

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    Data-driven saliency has recently gained a lot of attention thanks to the use of convolutional neural networks for predicting gaze fixations. In this paper, we go beyond standard approaches to saliency prediction, in which gaze maps are computed with a feed-forward network, and present a novel model which can predict accurate saliency maps by incorporating neural attentive mechanisms. The core of our solution is a convolutional long short-term memory that focuses on the most salient regions of the input image to iteratively refine the predicted saliency map. In addition, to tackle the center bias typical of human eye fixations, our model can learn a set of prior maps generated with Gaussian functions. We show, through an extensive evaluation, that the proposed architecture outperforms the current state-of-the-art on public saliency prediction datasets. We further study the contribution of each key component to demonstrate their robustness on different scenarios

    Shot, scene and keyframe ordering for interactive video re-use

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    This paper presents a complete system for shot and scene detection in broadcast videos, as well as a method to select the best representative key-frames, which could be used in new interactive interfaces for accessing large collections of edited videos. The final goal is to enable an improved access to video footage and the re-use of video content with the direct management of user-selected video-clips

    N-{3-[Bis(2-hydroxy­ethyl)amino­meth­yl]-5-nitro­phen­yl}benzamide

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    The title compound, C18H21N3O5, was prepared by the reaction of 3-benzamido-5-nitro­benzyl methane­sulfonate with diethano­lamine and is an inter­mediate in the synthesis of DNA minor-groove-binding polybenzamide agents capable of being conjugated to additional biologically active species. The asymmetric unit contains two independent mol­ecules, which differ only in the orientations of the hydroxy­ethyl groups. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link mol­ecules into one-dimensional chains

    Smart Lubrication System: sistema di controllo lubrificazione stampo in funzione della temperatura superficiale

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    La fase di lubrificazione stampo riveste un’importanza determinante sia dal punto di vista della cadenzaproduttiva che della qualità della produzione. La spruzzatura di distaccanti a base acqua asporta lamaggior parte del calore di solidificazione e raffreddamento dell’alluminio che ammonta a circa 250Kcal per ogni Kg. di lega e crea uno strato sulla cavità dello stampo che favorisce lo scorrimento dellalega e riduce l’effetto chimico-fisico di adesione. A tutti è noto l’effetto di incollaggio dell’alluminioall’acciaio tanto più evidente quanto più alta è la temperatura del metallo, la velocità e la pressionefinale, fenomeno noto come “metallizzazione”. Nel presente lavoro saranno riportati i risultati ottenuti“in campo” con la tecnologia “Smart Lubrication System”: sistema di controllo lubrificazione stampo infunzione della temperatura superficiale”

    Surface Core Level Shifts of Clean and Oxygen Covered Ru(0001)

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    We have performed high resolution XPS experiments of the Ru(0001) surface, both clean and covered with well-defined amounts of oxygen up to 1 ML coverage. For the clean surface we detected two distinct components in the Ru 3d_{5/2} core level spectra, for which a definite assignment was made using the high resolution Angle-Scan Photoelectron Diffraction approach. For the p(2x2), p(2x1), (2x2)-3O and (1x1)-O oxygen structures we found Ru 3d_{5/2} core level peaks which are shifted up to 1 eV to higher binding energies. Very good agreement with density functional theory calculations of these Surface Core Level Shifts (SCLS) is reported. The overriding parameter for the resulting Ru SCLSs turns out to be the number of directly coordinated O atoms. Since the calculations permit the separation of initial and final state effects, our results give valuable information for the understanding of bonding and screening at the surface, otherwise not accessible in the measurement of the core level energies alone.Comment: 16 pages including 10 figures. Submitted to Phys. Rev. B. Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm
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