Search results for "PULSES"

Probing the radio emission from air showers with polarization measurements

2014

The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed which cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially wit…

Sub-Wavelength Scale THz Source via Optical Rectification and its Spatio-Temporal Properties

2011

Optimal control and shortcuts to adiabaticity techniques in linear and non-linear systems : from ion cyclotron resonance to nuclear magnetic resonance

2021

The goal of our research is to develop efficient and robust control protocols for classical and quantum systems. To this end, we have applied optimal control theory (OCT) and shortcuts to adiabaticity (STA) with inverse engineering and motion planning approaches in three different examples, which are RC (Resistor Capacitor) circuits, Fourier Transform-Ion Cyclotron Resonance (FT-ICR), and Nuclear Magnetic Resonance (NMR). Some of our results are not limited to these systems but are rather general. We apply OCT and STA with an inverse engineering approach to control the time-evolution of the charge on a capacitor. We show that OCT is a member of the family of STA solutions. In order to contr…

Alignement moléculaire par impulsions laser ultrabrèves : Mesures & Applications

2009

The interaction of an intense ultrashort laser pulse with a molecular sample leads, after the end of the pulse, to molecular alignment at specific time under field-free conditions. This thesis is dedicated to the measurements and applications of this effect. The degree of alignment is determined through the variation of the refractive index induced by the rearrangement of the molecular dipoles. A two-dimensional technique allowing to measure molecular alignment on a single-shot basis is reported in this document. The alignment is then exploited in order to determine physical quantities which are usually difficult to estimate through others methods. The "cross-defocusing technique" has been …

Utilización de la prueba CATA para estudiar las representaciones, actitudes y creencias de los consumidores franceses hacia las legumbres, según su n…

2019

International audience

Understanding the low consumption of pulses among French non vegetarian consumers : combining direct and indirect approaches to identify barriers and…

2020

The objective of this thesis was to understand the barriers related to the consumption of pulses by French non-vegetarian consumers, by combining direct, indirect and implicit approaches.After showing that the social representations of consumers towards pulses are very different from those of professionals of the industry, we explored the mental representations, beliefs and knowledge about pulses among consumers. We showed that, even if the participants in our study had knowledge regarding pulses, they did not choose them frequently and associated them mostly with meat, which holds the central place of their meal. The difficulty of preparation of pulses seems to be a major obstacle to their…

Managing crop nitrogen and soil dynamics

2001

Despite extensive research grain legume seed protein content and yield remains low and unstable. Grain legume performances in the cropping system are highly dependent upon N nutrition of the crop relying on root assimilation of soil N in combination with symbiotic fixation of atmospheric dinitrogen. In order to improve the competitive ability of grain legumes for growth resources an enlargement of the crop surface area production in combination with a judicious management of both inputs and N acquisition (and allocation to the harvested organs) is needed. Competitive ability implies to take into account economical constraints and the crop production effect on the environment, reducing the a…

Legumes in 21st century Europe: present and future importance in agri-food systems? New challenges for reseach.

2013

Intensification of agriculture since 1950 has globally led to the decline of grain legume crops, which currently represent less than 3 % of arable crops in France and Europe. Nevertheless, legumes have several major assets (i) as plant proteins for animal feed and human food and (ii) as plants fixing atmospheric N2 and thereby saving nitrogen inputs in cropping systems, and (iii) as diversification crops. The analysis of forage and grain legume producing systems in France showed that the dominant system results in a lock-in of the different factors limiting legume insertion into the current systems. But legumes could have a major role to play in the agroecological transition towards more su…

Innovative extraction and separation technologies to improve the recovery of microalgae nutrients and bioactive compounds with potential beneficial e…

2023

Las microalgas son ricas en una gran variedad de compuestos bioactivos, que incluyen proteínas, polifenoles, polisacáridos, pigmentos, minerales, vitaminas, etc., que pueden utilizarse o separarse directamente para obtener componentes de mayor valor. La extracción y la separación son pasos clave en la obtención y posterior procesamiento de los productos relacionados con las microalgas, representando las tecnologías innovadoras de procesado una estrategia innovadora y eficiente para mejorar la calidad de estos productos. Actualmente, las microalgas y sus compuestos (nutrientes, compuestos bioactivos, etc.) se utilizan como alimento y también con finalidades desde el punto de vista de salud, …

Optically pumped Cs magnetometers enabling a high-sensitivity search for the neutron electric dipole moment

2020

An array of 16 laser-pumped scalar Cs magnetometers was part of the neutron electric dipole moment (nEDM) experiment taking data at the Paul Scherrer Institute in 2015 and 2016. It was deployed to measure the gradients of the experiment's magnetic field and to monitor their temporal evolution. The originality of the array lies in its compact design, in which a single near-infrared diode laser drives all magnetometers that are located in a high-vacuum chamber, with a selection of the sensors mounted on a high-voltage electrode. We describe details of the Cs sensors' construction and modes of operation, emphasizing the accuracy and sensitivity of the magnetic-field readout. We present two app…