4,800 research outputs found

    Broadening of H2_2O rotational lines by collision with He atoms at low temperature

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    We report pressure broadening coefficients for the 21 electric-dipole transitions between the eight lowest rotational levels of ortho-H2_2O and para-H2_2O molecules by collisions with He at temperatures from 20 to 120 K. These coefficients are derived from recently published experimental state-to-state rate coefficients for H2_2O:He inelastic collisions, plus an elastic contribution from close coupling calculations. The resulting coefficients are compared to the available experimental data. Mostly due to the elastic contribution, the pressure broadening coefficients differ much from line to line, and increase markedly at low temperature. The present results are meant as a guide for future experiments and astrophysical observations.Comment: 2 figures, 2 table

    An AER-Based Actuator Interface for Controlling an Anthropomorphic Robotic Hand

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    Bio-Inspired and Neuro-Inspired systems or circuits are a relatively novel approaches to solve real problems by mimicking the biology in its efficient solutions. Robotic also tries to mimic the biology and more particularly the human body structure and efficiency of the muscles, bones, articulations, etc. Address-Event-Representation (AER) is a communication protocol for transferring asynchronous events between VLSI chips, originally developed for neuro-inspired processing systems (for example, image processing). Such systems may consist of a complicated hierarchical structure with many chips that transmit data among them in real time, while performing some processing (for example, convolutions). The information transmitted is a sequence of spikes coded using high speed digital buses. These multi-layer and multi-chip AER systems perform actually not only image processing, but also audio processing, filtering, learning, locomotion, etc. This paper present an AER interface for controlling an anthropomorphic robotic hand with a neuro-inspired system.Unión Europea IST-2001-34124 (CAVIAR)Ministerio de Ciencia y Tecnología TIC-2003-08164-C03-0

    Novel U-Shaped D-A-D π-conjugated Systems with Mechanochromic Properties: An Experimental and Theoretical Vibrational Spectroscopic Investigation

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    Π-conjugated compounds have been widely studied in the last few decades due to their huge field of application in organic electronics. Specifically, stimuli-responsive Π-conjugated materials which are sensitive to external stimulus (i.e., temperature, pressure, etc) have several uses like sensors, probes and security inks, for example.1 In this work, we study two U-shape Donor-Acceptor-Donor (D-A-D) systems that are found to exhibit interesting thermal- and pressure-dependent properties. 2 They consist on two different conformers of phenothiazine-dibenzo[a,j]phenazine-phenothiazine which differs from the position of the phenothiazine respect to the dibenzophenzaine central core. Compound 1R is the equatorial-equatorial conformer and 1Y is the axial-axial conformer (Figure 1). The dibenzophenzaine group acts as an electron-acceptor whereas the phenothiazine unit acts as an electron-donor. It has been reported that this U-shape D-A-D compound shows a multi-active color changing in 3 steps and their luminescence changes with temperature, pressure and acid exposition.2 In this work, we aim to elucidate how the external stimuli (i.e. temperature, pressure, acid ambient) affects the molecular structure at both intra- and intermolecular level. To this end, we use UV-Vis absorption, Raman (Figure 1) and Infrared spectroscopy experiments in combination with DFT calculations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    El contacto entre las zonas de Ossa Morena y Sudportuguesa. Características y significado de la banda metamórfica de Aracena, en su sector central entre Aroche y Aracena (Huelva)

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    El contacto entre las zonas de Ossa Morena y Sudportuguesa está subrayado por la banda metamórfica de Aracena. Las características principales de esta región del macizo Ibérico pueden considerarse desde distintos puntos de vista: litológico, estructural, metamórfico, magmático, geoquímica, isotópico y experimental, y así se presentan en este artículo. La banda metamórfica de Aracena está dividida en dos dominios principales: el dominio oceánico está formado por metabasitas derivadas de un MORB (las metabasitas de Acebuches) y por un antiguo prisma de acrección. El dominio continental incluye gneises y migmatitas alumínicos, rocas de silicatos cálcicos, gneises leucocráticos, mármoles, anfibolitas, intrusiones sin/post-tectónicas de noritas ricas en Mg (con afinidad boninítica), así como rocas intrusivas post-tectónicas de composición ácida a básica. Las metabasitas de Acebuches sufrieron, en primer lugar, un metamorfismo de alta temperatura/baja presión que, en la actualidad, presenta un gradiente metamórfico invertido, y que estaba relacionado con un cabalgamiento vergente al SO. El pico térmico asociado a este evento metamórfico muestra un gradiente de edad, de forma que las edades más antiguas han sido obtenidas en el extremo oeste. La mitad inferior de la pila metabasítica de Acebuches fue afectada posteriormente por una deformación milonítica y un retrometamorfismo asociados a la zona de cizalla Sudibérica. Cuatro fases de deformación dúctil han sido definidas en el dominio continental: la fase CD-D1 estuvo relacionada con la generación de pliegues recumbentes de escala kilométrica. La fase CD-D2 se puede asociar a un colapso extensional, y es contemporánea con un metamorfismo de alta temperatura/baja presión que afectó al dominio continental y generó diversos complejos migmatíticos. La fase CD-D3 produjo pliegues simétricos verticales, mientras que la fase CD-D4 dio lugar a cabalgamientos vergentes al sur a los que se asociaron pliegues de propagación.Las principales características de la banda metamórfica de Aracena se interpretan como el resultado de la evolución de un punto triple de tipo fosa-fosa-dorsal. De acuerdo con el modelo propuesto, la interacción entre la dorsal y la zona de subducción dio como resultado la formación de una ventana astenosférica bajo el margen continental cabalgante, lo cual provocó el ascenso de la astenosfera y el consecuente rebote térmico. Esta unión triple migro a lo largo del margen continental hacia el este, lo que generó un cinturón metamórfico de alta temperatura/baja presión en el contacto entre las zonas de Ossa Morena y Sudportuguesa

    Mixing Effects in the Crystallization of Supercooled Quantum Binary Liquids

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    By means of Raman spectroscopy of liquid microjets we have investigated the crystallization process of supercooled quantum liquid mixtures composed of parahydrogen (pH2_2) diluted with small amounts of up to 5\% of either neon or orthodeuterium (oD2_2), and of oD2_2 diluted with either Ne or pH2_2. We show that the introduction of Ne impurities affects the crystallization kinetics in both the pH2_2-Ne and oD2_2-Ne mixtures in terms of a significant reduction of the crystal growth rate, similarly to what found in our previous work on supercooled pH2_2-oD2_2 liquid mixtures [M. K\"uhnel et {\it al.}, Phys. Rev. B \textbf{89}, 180506(R) (2014)]. Our experimental results, in combination with path-integral simulations of the supercooled liquid mixtures, suggest in particular a correlation between the measured growth rates and the ratio of the effective particle sizes originating from quantum delocalization effects. We further show that the crystalline structure of the mixture is also affected to a large extent by the presence of the Ne impurities, which likely initiate the freezing process through the formation of Ne crystallites.Comment: 19 pages, 7 figures, submitted to J. Chem. Phy

    Clustering of energy balance-related behaviors and parental education in European children : the ENERGY-project

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    Background:Recent research and literature reviews show that, among schoolchildren, some specific energy balance-related behaviors (EBRBs) are relevant for overweight and obesity prevention. It is also well known that the prevalence of overweight and obesity is considerably higher among schoolchildren from lower socio-economic backgrounds. This study examines whether sugared drinks intake, physical activity, screen time and usual sleep duration cluster in reliable and meaningful ways among European children, and whether the identified clusters could be characterized by parental education. Methods: The cross-sectional study comprised a total of 5284 children (46% male), from seven European countries participating in the ENERGY-project ("EuropeaN Energy balance Research to prevent excessive weight Gain among Youth"). Information on sugared drinks intake, physical activity, screen time and usual sleep duration was obtained using validated self-report questionnaires. Based on these behaviors, gender-specific cluster analysis was performed. Associations with parental education were identified using chi-square tests and odds ratios. Results: Five meaningful and stable clusters were found for both genders. The cluster with high physical activity level showed the highest proportion of participants with highly educated parents, while clusters with high sugared drinks consumption, high screen time and low sleep duration were more prevalent in the group with lower educated parents. Odds ratio showed that children with lower educated parents were less likely to be allocated in the active cluster and more likely to be allocated in the low activity/sedentary pattern cluster. Conclusions: Children with lower educated parents seemed to be more likely to present unhealthier EBRBs clustering, mainly characterized by their self-reported time spent on physical activity and screen viewing. Therefore, special focus should be given to lower educated parents and their children in order to develop effective primary prevention strategies

    A general perspective of the characterization and quantification of nanoparticles: Imaging, spectroscopic, and separation techniques

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    This article gives an overview of the different techniques used to identify, characterize, and quantify engineered nanoparticles (ENPs). The state-of-the-art of the field is summarized, and the different characterization techniques have been grouped according to the information they can provide. In addition, some selected applications are highlighted for each technique. The classification of the techniques has been carried out according to the main physical and chemical properties of the nanoparticles such as morphology, size, polydispersity characteristics, structural information, and elemental composition. Microscopy techniques including optical, electron and X-ray microscopy, and separation techniques with and without hyphenated detection systems are discussed. For each of these groups, a brief description of the techniques, specific features, and concepts, as well as several examples, are described.Junta de Andalucía FQM-5974CEI-Biotic Granada CEI2013- MP-1

    Investigating Piezochromic Properties of πconjugated Materials: a combined Raman and DFT Study

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    Π-conjugated materials have been studied for decades due to their great interest in organic electronics. Among them, piezochromic materials, which exhibit color changes resulting from external pressure or mechanical grinding, become very attractive from a scientific viewpoint owing to their potential applications as pressure-sensing and opticalrecording systems1. The main target of the present work is to develop a joint experimental and theoretical approach able to deliver crucial information for the understanding of the structural effects causing piezochromic changes. To this end, we will focus our attention on two families of -conjugated materials with potential application as sensors. The first one is a family of 9,10-Bis((E)-n(pyrid-2-yl)vinyl) anthracene, BPnVA (n=2 orto-,3 metha- and 4 para-) compounds, see Figure 1. Interestingly, these three compounds with varying position of the nitrogen on the external pyridyl group exhibit different molecular packing modes. Grinding and the application of external pressure on the powder also led to a strong change in their photoluminescence color.2 The second familiy is based on the N,N’-Bis-Boc-3,3’-di(pyren-1yl)-2,2’-biindole compound (compound 1c in Figure 1) which also shows photoluminescence under pressure application. However, the molecular packing induced by this phenomenon is still under study 3. In both cases, it will be also very interesting to determine how temperature affects the vibrational structure of these systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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