Search results for "confinement"
showing 10 items of 213 documents
Confined quarks and the neutrinoless ββ decay
1990
Abstract The half life of the neutrinoless double beta decay of 76Ge into the ground state of 76Se is calculated in a relativistic quark confinement model. The neutron-proton quasi-particle random phase approximation is used to evaluate the nuclear matrix elements involved in the decay amplitude. We avoid the closure approximation, but compare our results with this approximation. From the experimental half life we deduce an upper limit for the Majorana mass of the neutrino and estimate the right-handed contribution to the charged weak current.
Propan-2-ol dehydration on H-ZSM-5 and H-Y zeolite: a DFT study
2012
The catalytic dehydration of propan-2-ol over H-Y and H-ZMS-5 aluminated zeolite models, mimicking both internal cavities and external surfaces, was studied by DFT calculations to investigate the reaction mechanism. After the adsorption of propan-2-ol on the zeolite, the dehydration mechanism starts with alcohol protonation, occurring by one acidic –OH group of the zeolite fragment, followed by a concerted β-elimination to give propene. The catalytic activity is affected by the size of the zeolite cavity, which is larger in the H-Y than in the H-ZMS-5 zeolite. The adsorption energy of the reagent, as an example, decreases in the order: H-Y cavity ≃ H-ZMS-5 surface > H-ZMS-5 cavity, pointing…
Pratiques d'enseignement - apprentissage en contexte de confinement : « continuité » ou rupture pédagogique ? La recherche action EDiCOViD
2021
International audience
Structure and Dynamics of Confined Liquids: Challenges and Perspectives for the X-ray Surface Forces Apparatus
2019
Preprint of the open access article Weiss, H., Cheng, H.-W., Mars, J., Li, H., Merola, C., Renner, F. U., Honkimäki, V., Valtiner, M., & Mezger, M. (2019). Structure and Dynamics of Confined Liquids: Challenges and Perspectives for the X-ray Surface Forces Apparatus. Langmuir, 35(51), 16679–16692. https://doi.org/10.1021/acs.langmuir.9b01215
Direct interpretation of near-field optical images
2001
International audience; The interpretation of the detection process in near-field optical microscopy is reviewed on the basis of a discussion about the possibility of establishing direct comparisons between experimental images and the solutions of Maxwell equations or the electromagnetic local density of states. On the basis of simple physical arguments, it is expected that the solutions of Maxwell equations should agree with images obtained by collecting mode near-field microscopes, while the electromagnetic local density of states should be considered to provide a practical interpretation of illumination mode near-field microscopes. We review collecting mode near-field microscope images w…
Analysis of metallic impurity content by means of VUV and SXR diagnostics in hybrid discharges with hot-spots on the JET-ITER-like wall poloidal limi…
2019
In preparation for the upcoming JET D-T campaign, great effort has been devoted during the 2015-2016 JET campaigns with the ITER-like wall (ILW) to the extension of the high performance H-mode phase in baseline and hybrid scenarios. Hybrid discharges were the only ones that have been stopped by the real-time vessel protection system due hot-spot formation on the outboard poloidal limiter. Generation of hot-spots was linked to the application of high neutral beams injection and ion cyclotron resonance heating (ICRH) power. In tokamaks with high-Z plasma components, the use of ICRH heating is also accompanied by an increased metallic impurity content. Simultaneous control of hot-spot temperat…
Covid-19 : quel bilan critique ? (Partie II)
2021
International audience
Covid-19 : quel bilan critique ? (Partie I)
2021
International audience
Health-Related Behaviors Among School-Aged Children and Adolescents During the Spanish Covid-19 Confinement
2020
In response to the coronavirus disease 2019 (Covid-19) world pandemic, affected countries such as Spain enacted measures comprising compulsory confinement as well as restrictions regarding free movement. Such measures likely influence children's and adolescents' lifestyles. Our study aimed to investigate the impact that the Covid-19 confinement has on health-related behaviors (HRBs) among Spanish children and adolescents. An online survey was administered to 516 parents to collect data about 860 children and adolescents (49.2% girls) aged between 3 and 16 years in relation to physical activity, screen exposure, sleep time, and fruit and vegetable consumption during the Covid-19 confinement.…
Survey data on the consequences of COVID-19 and home confinement on the educational community and families in Spain
2021
[EN] This paper presents a dataset concerning the consequences of the COVID-19 pandemic and home confinement on the educational community and families, and the possibilities and opportunities for the return to schools. Data were collected through an online based cross-sectional survey between June 29, 2020 and July 12, 2020 in Spain. A total of 7,305 people who had children in their care during the COVID-19 crisis and the home-confinement period responded to the survey. The survey contained items concerning (i) socio-demographic information, (ii) conciliation of work, personal and family life during confinement, (iii) the impact of the pandemic on the respondent's family, and (iv) the respo…