842 research outputs found

    PZT thick films by diol chemical solution deposition

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    Process optimization and properties of lead zirconate titanate (PZT) films for piezoelectric micromachined ultrasonic transducers (pMUTs) for scanning probe devices will be presented. The goal of the work was a replacement of the tetragenic and mutagenic solvent and a decrease of time-consuming PZT 2-methoxy ethanol (2MOE) route. An alternative diol-based solution synthesis process was developed and "Design Of Experiment” (DOE) was used to achieve processing optimization for thick and crack free films. Tight parameter control allowed to develop a highly reproducible PZT diol process. The crystallization behaviour of crack-free PbZr0.53Ti0.47O3 films (1-5μm) with oriented perovskite structure was examined by X-ray diffraction and surface analysis using scanning electron microscopy. Piezoelectric and dielectric properties were examined. The effective transverse piezoelectric coefficient e 31,f of sol-gel processed films was investigated for 4μm thick layers. Best properties were achieved with {1 0 0}-textured films, where a remanent e 31,f value of −7.3C/m2 was measured for 4.1μm thick film

    On a Three-Dimensional Gravity Model with Higher Derivatives

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    The purpose of this work is to present a model for 3D massive gravity with topological and higher-derivative terms. Causality and unitarity are discussed at tree-level. Power-counting renormalizability is also contemplated.Comment: 9 pages, Latex, no figures; to be published in Gen. Rel. Gra

    IN2LAMA: INertial lidar localisation and mapping

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    © 2019 IEEE. In this paper, we introduce a probabilistic framework for INertial Lidar Localisation And MApping (IN2LAMA). Most of today's lidars are based on spinning mechanisms that do not capture snapshots of the environment. As a result, movement of the sensor can occur while scanning. Without a good estimation of this motion, the resulting point clouds might be distorted. In the lidar mapping literature, a constant velocity motion model is commonly assumed. This is an approximation that does not necessarily always hold. The key idea of the proposed framework is to exploit preintegrated measurements over upsampled inertial data to handle motion distortion without the need for any explicit motion-model. It tightly integrates inertial and lidar data in a batch on-manifold optimisation formulation. Using temporally precise upsampled preintegrated measurement allows frame-to-frame planar and edge features association. Moreover, features are re-computed when the estimate of the state changes, consolidating front-end and back-end interaction. We validate the effectiveness of the approach through simulated and real data

    3D Lidar-IMU Calibration Based on Upsampled Preintegrated Measurements for Motion Distortion Correction

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    © 2018 IEEE. In this paper, we present a probabilistic framework to recover the extrinsic calibration parameters of a lidar-IMU sensing system. Unlike global-shutter cameras, lidars do not take single snapshots of the environment. Instead, lidars collect a succession of 3D-points generally grouped in scans. If these points are assumed to be expressed in a common frame, this becomes an issue when the sensor moves rapidly in the environment causing motion distortion. The fundamental idea of our proposed framework is to use preintegration over interpolated inertial measurements to characterise the motion distortion in each lidar scan. Moreover, by using a set of planes as a calibration target, the proposed method makes use of lidar point-to-plane distances to jointly calibrate and localise the system using on-manifold optimisation. The calibration does not rely on a predefined target as arbitrary planes are detected and modelled in the first lidar scan. Simulated and real data are used to show the effectiveness of the proposed method

    Jogo patológico em mulheres: uma revisão

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    Pathological gambling was only recently recognized as a psychiatric disorder (DSM-III, APA, 1980). Most studies of pathological gambling include only male subjects. Despite the paucity of information, it is likely that at least one-third of pathological gamblers are women. The objective of this article is to review clinical and epidemiological characteristics of female gamblers as compared to their male counterparts. MEDLINE and PsycINFO were searched for investigational studies and reviews of the past 10 years on clinical (sociodemographic, course and progression, psychiatric comorbidities, genetics, and personality) and epidemiological aspects of female gamblers. Other relevant articles were also selected from reference lists. It is concluded that the current literature indicates some common characteristics in female and male gamblers, but it also indicates the possibility that each gender may carry etiopathogenic differences that when better understood should lead to improved treatment and prevention strategies.Ainda que jogos de azar e os problemas a eles relacionados sejam antigos para a humanidade, o Jogo Patológico, como alteração do comportamento humano, somente passou a ser reconhecido oficialmente como transtorno psiquiátrico a partir de sua inclusão na 3ª Edição do Manual Diagnóstico e Estatístico de Transtornos Mentais (APA,1980). A maioria dos estudos sobre jogadores patológicos tem como base uma população eminentemente masculina. Entretanto, estima-se que pelo menos um terço dos indivíduos que recebem este diagnóstico sejam mulheres. O objetivo deste estudo foi revisar características clínicas e epidemiológicas de jogadoras comparadas a jogadores. As bases de dados MEDLINE e PsycINFO foram consultadas a respeito de estudos sobre Jogo Patológico publicados nos últimos dez anos, com especial enfoque para características clínicas (dados sócio-demográficos, curso e evolução, comorbidade psiquiátrica, genética e personalidade) e epidemiologia. Artigos relevantes publicados anteriormente ao período escolhido de revisão foram selecionados a partir da lista original de referências. Os autores concluem que a literatura atual indica que jogadoras e jogadores apresentam semelhanças, mas carreiam possíveis diferenças etiopatogênicas cujo esclarecimento deverá aprimorar as estratégias de tratamento e prevenção

    Uniform convergence to equilibrium for granular media

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    We study the long time asymptotics of a nonlinear, nonlocal equation used in the modelling of granular media. We prove a uniform exponential convergence to equilibrium for degenerately convex and non convex interaction or confinement potentials, improving in particular results by J. A. Carrillo, R. J. McCann and C. Villani. The method is based on studying the dissipation of the Wasserstein distance between a solution and the steady state

    Computational algorithms for the segmentation of the human ear

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    The main goal of this project is to identify an efficient segmentation algorithm for each anatomic structure of the ear. Therefore, in this paper, it is presented and analyzed computational algorithms that have been used to segment structures in images, especially of the human ear in Computed Tomography (CT) images

    PZT thick films by diol chemical solution deposition

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    Process optimization and properties of lead zirconate titanate (PZT) films for piezoelectric micromachined ultrasonic transducers (pMUTs) for scanning probe devices will be presented. The goal of the work was a replacement of the tetragenic and mutagenic solvent and a decrease of time-consuming PZT 2-methoxy ethanol (2MOE) route. An alternative diol-based solution synthesis process was developed and "Design Of Experiment" (DOE) was used to achieve processing optimization for thick and crack free films. Tight parameter control allowed to develop a highly reproducible PZT diol process. The crystallization behaviour of crack-free PbZr0.53Ti0.47O3 films (1-5 mu m) with oriented perovskite structure was examined by X-ray diffraction and surface analysis using scanning electron microscopy. Piezoelectric and dielectric properties were examined. The effective transverse piezoelectric coefficient e(31,f) of sol-gel processed films was investigated for 4 mu m thick layers. Best properties were achieved with {1 0 0}-textured films, where a remanent e(31,f) value of -7.3 C/m(2) was measured for 4.1 mu m thick films

    Improved modelling of helium and tritium production for spallation targets

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    Reliable predictions of light charged particle production in spallation reactions are important to correctly assess gas production in spallation targets. In particular, the helium production yield is important for assessing damage in the window separating the accelerator vacuum from a spallation target, and tritium is a major contributor to the target radioactivity. Up to now, the models available in the MCNPX transport code, including the widely used default option Bertini-Dresner and the INCL4.2-ABLA combination of models, were not able to correctly predict light charged particle yields. The work done recently on both the intranuclear cascade model INCL4, in which cluster emission through a coalescence process has been introduced, and on the de-excitation model ABLA allows correcting these deficiencies. This paper shows that the coalescence emission plays an important role in the tritium and 3He^3He production and that the combination of the newly developed versions of the codes, INCL4.5-ABLA07, now lead to good predictions of both helium and tritium cross sections over a wide incident energy range. Comparisons with other available models are also presented.Comment: 6 pages, 9 figure
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