Structural investigation of (111) oriented (BiFeO3)(1-x){\Lambda}/(LaFeO3)x{\Lambda} superlattices by X-ray diffraction and Raman spectroscopy

(BiFeO3)(1-x){\Lambda}/(LaFeO3)x{\Lambda} superlattices (SLs) with varying x have been grown by pulsed laser deposition on (111) oriented SrTiO3 substrates. In order to obtain good epitaxy and flat samples a conducting SrRuO3 buffer has been deposited prior to the superlattices to screen the polar mismatch for such (111) SrTiO3 orientation. X-ray diffraction reciprocal space mapping on different family of planes were collected and evidenced a room temperature structural change at x=0.5 from a rhombohedral/monoclinic structure for rich BiFeO3 to an orthorhombic symmetry for rich LaFeO3. This symmetry change has been confirmed by Raman spectroscopy and demonstrates the different phase stability compared to similar SLs grown on (100) SrTiO3. The strongly anisotropic strain and oxygen octahedral rotation/tilt system compatibility at the interfaces probably explain the orientation dependence of the phase stability in such superlattices.Comment: 17 pages, 3 figure

Hybrid intelligent framework for automated medical learning

This paper investigates the automated medical learning and proposes hybrid intelligent framework, called Hybrid Automated Medical Learning (HAML). The goal is the efficient combination of several intelligent components in order to automatically learn the medical data. Multi agents system is proposed by using distributed deep learning, and knowledge graph for learning medical data. The distributed deep learning is used for efficient learning of the different agents in the system, where the knowledge graph is used for dealing with heterogeneous medical data. To demonstrate the usefulness and accuracy of the HAML framework, intensive simulations on medical data were conducted. A wide range of experiments were conducted to verify the efficiency of the proposed system. Three case studies are discussed in this research, the first case study is related to process mining, and more precisely on the ability of HAML to detect relevant patterns from event medical data. The second case study is related to smart building, and the ability of HAML to recognize the different activities of the patients. The third one is related to medical image retrieval, and the ability of HAML to find the most relevant medical images according to the image query. The results show that the developed HAML achieves good performance compared to the most up-to-date medical learning models regarding both the computational and cost the quality of returned solutionspublishedVersio

Intrinsic dead layer effects in relaxed epitaxial BaTiO3 thin film grown by pulsed laser deposition

MEM acknowledges a support from the Region of Haut de France and IPR the Ministry of Education and Science of the Russian Federation (research project 3.1649.2017/PP).Epitaxial BaTiO3 (BT) thin film of about 400 nm thickness was grown on LaSr0.5Co0.5O3 (LSCO) coated (001)MgO using pulsed laser deposition. Ferroelectric properties of the BT thin film in Pt/BT/LSCO/MgO heterostructure capacitor configuration were investigated. Dynamic P-E hysteresis loops at room temperature showed ferroelectric behavior with Ps = 32 μC/cm2, Pr = 14 μC/cm2 and EC = 65 kV/cm. Static C-V measurements confirmed reversible switching with a coercive field EC = 15 kV/cm. Basing on a model taking into account an interface dead-layer we show that the capacitance-voltage “butterfly” loops imply only 25% switching of dipoles that inferred from dynamic polarization-field loops (~ 4 and ~ 16 kV/cm, respectively). Dielectric permittivity as a function of temperature revealed a first-order ferroelectric-to-paraelectric (FE-PE) phase transition in the BT film characterized by a maximum at TC ~ 130 °C. The very large (~ 126 K at 1 kHz) difference between TC and the extrapolated Curie-Weiss temperature T0 is attributed to the dead-layer effects.PostprintPeer reviewe

Process improvement proposal for the reduction of machine setup time in a copper transformation company using lean manufacturing tools

This study aimed to identify the causes of significant problems existing in the metallurgical sector, and a solution is proposed for the setup process. We detail the theoretical background of the processes in the lean manufacturing methodology, which will be applied to a rolling machine. Further, we provide a brief description of the company and the sector’s problems. We describe success stories of companies that implemented various lean manufacturing tools. We also present some of the results achieved across sectors to gain an in-depth understanding of the technique and a practical support of the implemented model. Our proposal is based on the lean manufacturing methodology; tools such as Single Minute Exchanges of Dies, Kaizen, 5S, and value stream mapping (VSM) will be used to reduce setup times and to impact machine layout and productivity positively. We also show the implementation results of a pilot plan conducted in the company over a period of more than 3 months.Revisión por pare

SUBARU prime focus spectrograph: integration, testing and performance for the first spectrograph

The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope consists in four identical spectrographs fed by 600 fibers each. Each spectrograph is composed by an optical entrance unit that creates a collimated beam and distributes the light to three channels, two visibles and one near infrared. This paper presents the on-going effort for the tests & integration process for the first spectrograph channel: we have developed a detailed Assembly Integration and Test (AIT) plan, as well as the methods, detailed processes and I&T tools. We describe the tools we designed to assemble the parts and to test the performance of the spectrograph. We also report on the thermal acceptance tests we performed on the first visible camera unit. We also report on and discuss the technical difficulties that did appear during this integration phase. Finally, we detail the important logistic process that is require to transport the components from other country to Marseille

Endpoints for randomized controlled clinical trials for COVID-19 treatments

Background: Endpoint choice for randomized controlled trials of treatments for novel coronavirus-induced disease (COVID-19) is complex. Trials must start rapidly to identify treatments that can be used as part of the outbreak response, in the midst of considerable uncertainty and limited information. COVID-19 presentation is heterogeneous, ranging from mild disease that improves within days to critical disease that can last weeks to over a month and can end in death. While improvement in mortality would provide unquestionable evidence about the clinical significance of a treatment, sample sizes for a study evaluating mortality are large and may be impractical, particularly given a multitude of putative therapies to evaluate. Furthermore, patient states in between “cure” and “death” represent meaningful distinctions. Clinical severity scores have been proposed as an alternative. However, the appropriate summary measure for severity scores has been the subject of debate, particularly given the variable time course of COVID-19. Outcomes measured at fixed time points, such as a comparison of severity scores between treatment and control at day 14, may risk missing the time of clinical benefit. An endpoint such as time to improvement (or recovery) avoids the timing problem. However, some have argued that power losses will result from reducing the ordinal scale to a binary state of “recovered” versus “not recovered.” Methods: We evaluate statistical power for possible trial endpoints for COVID-19 treatment trials using simulation models and data from two recent COVID-19 treatment trials. Results: Power for fixed time-point methods depends heavily on the time selected for evaluation. Time-to-event approaches have reasonable statistical power, even when compared with a fixed time-point method evaluated at the optimal time. Discussion: Time-to-event analysis methods have advantages in the COVID-19 setting, unless the optimal time for evaluating treatment effect is known in advance. Even when the optimal time is known, a time-to-event approach may increase power for interim analyses. © The Author(s) 2020

Prime Focus Spectrograph (PFS) for the Subaru telescope: Ongoing integration and future plans

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ∼ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward

Phonon transmission via a three–terminal junction in low dimensional wave-guides

Coherent phonon scattering and transmission via a three-terminal junction in low-dimensional structures is investigated. The model system consists of two-dimensional crystalline wave-guides, constructed of double atomic chains that are joined together by a nanostructured T-shaped junction. The matching method theoretical approach is used to study the dynamics of the system. A calculation is presented for the coherent reflection and transmission scattering probabilities of the system phonons, as elements of a Landauer type scattering matrix. The scattering and transmission spectra via the T-shaped junction are analyzed as a function of the incident frequency per propagating mode of the perfect wave-guides. Our results show that the junction is an effective phonon splitter and suggest that its characteristics may be controlled by varying its nanometric parameters. Asymmetric Fano-like resonances are observed in the spectra which result from the coherent coupling between the localized modes of the T-shaped junction and the propagating modes of the wave-guides

Etude des efforts et de la température de coupe lors de tournage dur de l’acier AISI 52100 par un outil CBN

Dans ce travail nous présentons les résultats théoriques et expérimentaux d’une étude dynamique de la coupe des métaux concernant la mesure des efforts et la température de coupe lors de l’usinage e l’acier à roulement AISI 52100 (60HRC) avec un outil en nitrure de bore cubique CBN 7020. Cette étude, basé sur des essais unifactoriel et multifactorielle (vitesse de coupe, avance et la profondeur de passe) permis la mise en évidence de l’influence des conditions de coupe sur les composantes de l’effort de coupe. Le traitement des résultats obtenus a permis la détermination des différents modèles qui expriment la relation entre les paramètres d’usinage étudiés et les composantes de l’effort de coupe. Nous nous somme également intéressés à l’étude de l’influence de l’usure en dépouille de la partie active de l’outil sur l’évolution des efforts de coupe permettant la proposition d’une relation puissance entre l’effort de coupe et l’usure puisque ces deux paramètres s’influencent mutuellement. Enfin, une analyse des différents résultats obtenus été effectuée.Mots clés: Efforts de coupe; pression spécifique de coupe; usinage dur; CBN; conditions de coupe. In the present work, theoretical and experimental results of dynamics study of metal cutting are presented. This investigation is concerned with the cutting force and temperature measurement during machining of hardened bearing steel AISI 52100 using a Cubic Boron Nitride tool CBN7020. The experimental tests based on both unifatorial and multifactirial methods whose parameters are cutting speed, feed rate and depth of cut led to the determination of the cutting conditions effects on cutting force components. The treatment of the results obtained allowed us the deduction of various models, which express the relation between the studied parameters of machining and the cutting force components. A study of the influence of the flank wear on the evolution of cutting force has also been carried out in order to develop a power relation between the cutting force and the flank wear. Finally, an analysis of the different obtained results has been made.Keywords: Cutting force; Cutting specific pressure; hard machining; CBN; cutting conditions