42 research outputs found
Thulium and ytterbium-doped titanium oxide thin films deposited by ultrasonic spray pyrolysis
Thin films of thulium and ytterbium-doped titanium oxide were grown by
metal-organic spray pyrolysis deposition from titanium(IV)oxide
bis(acetylacetonate), thulium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate)
and ytterbium(III) tris(acetylacetonate). Deposition temperatures have been
investigated from 300{\deg}C to 600{\deg}C. Films have been studied regarding
their crystallity and doping quality. Structural and composition
characterisations of TiO2:Tm,Yb were performed by electron microprobe, X-ray
diffraction and Fourier transform infrared spectroscopy. The deposition rate
can reach 0.8 \mum/h. The anatase phase of TiO2 was obtained after synthesis at
400{\deg}C or higher. Organic contamination at low deposition temperature is
eliminated by annealing treatments.Comment: 6 pages, 6 figure
Thulium and ytterbium-doped titania thin films deposited by MOCVD
In this study we synthesized thin films of titanium oxide doped with thulium
and/or ytterbium to modify the incident spectrum on the solar cells. This could
be achieved either by photoluminescence up-converting devices, or
down-converting devices. As down-converter thin films our work deals with
thulium and ytterbium-doped titanium dioxide. Thulium and ytterbium will act as
sensitizer and emitter, respectively. The rare-earth doped thin films are
deposited by aerosol-assisted MOCVD using organo-metallic precursors such as
titanium dioxide acetylacetonate, thulium and ytterbium
tetramethylheptanedionate solved in different solvents. These films have been
deposited on silicon substrates under different deposition conditions
(temperature and dopant concentrations for example). Adherent films have been
obtained for deposition temperatures ranging from 300{\deg}C to 600{\deg}C. The
deposition rate varies from 0.1 to 1 \mu m/h. The anatase phase is obtained at
substrate temperature above 400{\deg}C. Further annealing is required to
exhibit luminescence and eliminate organic remnants of the precursors. The
physicochemical and luminescent properties of the deposited films were analyzed
versus the different deposition parameters and annealing conditions. We showed
that absorbed light in the near-UV blue range is re-emitted by the ytterbium at
980 nm and by a thulium band around 800 nm.Comment: 4 pages, 6 figures, proceedin
Echocardiography in patients with hypertrophic cardiomyopathy: usefulness of old and new techniques in the diagnosis and pathophysiological assessment
Hypertrophic cardiomyopathy (HCM) is one of the most common inherited cardiomyopathy. The identification of patients with HCM is sometimes still a challenge. Moreover, the pathophysiology of the disease is complex because of left ventricular hyper-contractile state, diastolic dysfunction, ischemia and obstruction which can be coexistent in the same patient. In this review, we discuss the current and emerging echocardiographic methodology that can help physicians in the correct diagnostic and pathophysiological assessment of patients with HCM
Mutations in the cardiac troponin T gene show various prognoses in Japanese patients with hypertrophic cardiomyopathy
The DBR Methodology for the Study of Context in Learning
In the Design-Based Research (DBR) methodology, the process is as im-portant as the product, and each iteration is considered a sub-result leading to the next one. This methodology is being used in the TEE project, to both study and elaborate solutions for Learning in Context. This paper describes the origins of the project, as well as the steps taken to conduct it, with a perspective for future work. The DBR methodology is presented as applied in the TEEC project (TEEC= Tech-nologies Educatives et Enseignement en Contexte).
Keywords: Design-Based Research, DBR, Methodology, Modelling, Context, Learning, Intelligent Tutoring System
Elaborating the Context Calculator: A Design Experiment in Geothermy
Abstract. This paper presents a research project in science education that is positioned at the intersection of computer science and context in learning. The main objective is to improve learning process by creating a software tool that participates, from the inception to the achievement, in the design of leaning scenarios, based on context effects, and, to show that context effectsâ learning is an efficient method in the development of studentâs knowledge regarding a concept. The software will
compute differences between two â or more â external contexts based on specific parameters, related to the phenomenon or object that students are expected to study. The elaboration of the calculator (âthe MazCalcâ) is conducted using the design based research theory, meaning that several iterations of learning field experiments are conducted in order to collect relevant data which are used for the tool creation. In this paper, the design of the scenario involves students from North America and from the French West Indies and the concept studied is about geothermal energy. The instantiation of the context calculator is made with the geothermal object of study, and the differences are computed in the calculator between the two contexts mentioned. This example makes possible to validate the link between context effects predicted and observed, and also to study the impact of external context on the learning process. This study has been conducted thanks to the GEOTREF project support. Keywords : Modelling, Context, Science Education, Learning, Context Effects,
Geotherm
Croissance et caractĂ©risation de films minces luminescents dopĂ©s terres rares par MOCVD en vue dâapplication pour la conversion du spectre solaire"
National audienc