Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

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Reliable metal organic frameworks (MOF) and derivatives for radioactive gas detection

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-10-2020

SL-DRT-20-1117

guillaume.bertrand@cea.fr

This PhD position will be carried out in the frame of the SPARTE European project, which aims at developing porous scintillators in order to detect radioactive gases. The main goal of this PhD thesis is to explore the rich family of Metal Organic Frameworks (MOFs), and specifically the ones with fluorescent organic building blocks. The study will follow good preliminary results that our team got with Zinc-based MOFs and MOFs derivatives. We would like to extend the scope of these good results to other porous frameworks. Synthesis of new fluorescent ligands will also be considered. Photophysical properties of these materials will also be explored as well as their ability to concentrate and detect radioactive gases. This last measurement will be performed on a unique in the world labmade radioactive-gas bench. The PhD candidate is expected to perform inorganic solvothermal synthesis as well as photophysical characterization. He/she will also work on the radioactive gas bench set up. We wish to recruit somebody with a strong background in inorganic or organic chemistry and an open mind towards material-science technics. This thesis will be performed in two different laboratories, with two technical supervisers (Guillaume BERTRAND - LCAE and Benoît SABOT - LNHB/LMA) and a PhD director (Matthieu HAMEL - LCAE).

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Power Efficient AI-based IoT Physical Layer

Département Systèmes (LETI)

Laboratoire Communication des Objets Intelligents

01-10-2020

SL-DRT-20-1122

valerian.mannoni@cea.fr

Communication networks, IOT, radiofrequencies and antennas (.pdf)

The Internet of Things (IoT) is now a reality: more than 9 billion objects are already connected, 25 billion will be by 2025. To be effective, radio communication systems for the IoT must have a large coverage (operating at very low sensitivity levels) while having low energy consumption. In addition, the usual mode of operation of its systems is to communicate small messages sporadically and mainly uplink. The combination of all these constraints has led to the emergence of radio systems specific to the IoT such as LoRa, SigFox or NB-IoT and its current developments in 5G. However, it has been shown that these technologies do not simultaneously meet the needs of the IoT and that it is necessary to propose a new physical layer capable of addressing all the contradictory requirements of the IoT: - Low sensitivity (good performance at low spectral efficiency) for short messages (short error correcting codes and associated decoders). - Low power consumption (constant envelope waveform and high throughput). Limited and optimized signaling overhead. To achieve these objectives, algorithms based on Artificial Intelligence (AI) will be considered, in particular at the receiver/decoder level (embedded AI).

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DC/DC converter based on piezoelectric material and adiabatic power transfer

Département Systèmes (LETI)

Laboratoire Electronique Energie et Puissance

01-10-2020

SL-DRT-20-1148

ghislain.despesse@cea.fr

Energy efficiency for smart buildings, electrical mobility and industrial processes (.pdf)

The aim of this thesis is to design high-efficiency power converters based on resonating piezoelectric transducers. A large part of the work is to develop the electrical cycle able to energetically maintain the piezoelectric resonator in resonance and ensure zero-voltage switching, for electrical energy transfer from the source to the piezoelectric resonator or from the piezoelectric resonator to the output, in order to minimize the losses. An electronic power management circuit will be designed to enable this ideal energetic cycle. This electronic circuit will include several regulation loops to ensure the system stability and regulate the electrical output power. Finally, a study of the piezoelectric transducer size reduction will be done in view of a MEMS (Micro Electro Mechanical System) integration.

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Fatigue behaviour of low alloyed steels under Natural gas / hydrogen gas mixtures

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire Conception et Assemblages

01-10-2020

SL-DRT-20-1174

laurent.briottet@cea.fr

Smart Energy grids (.pdf)

In the context of future developments, ?GRTgaz' examines the possibility of hydrogen introduction in its natural gas grid. In order to guarantee the grid security, it is necessary to investigate the effect of hydrogenated natural gas on the behavior of pipelines steels, in particular under cyclic charges. The LITEN/LCA laboratory of CEA/GRENOBLE is engaged in a common study with ?GRTgas', aiming to evaluate the behavior of steels used for pipeline manufacturing in mixtures of natural gas (NG) and H2 in order to improve the lifetime predictability of components in the field conditions. The experimental strategy is to investigate the low cycle fatigue behavior of steels and to determine crack propagation characteristics in gaseous NG/H2 mixtures under various pressure. The Materials Science and Engineering (SMS) research center of Mines Saint-Etienne is associated with the LITEN/LCA laboratory in this project, in particular concerning the understanding of interactions between hydrogen and cyclic plasticity as well as the mechanisms of hydrogen embrittlement (HE) in this family of low alloy steels. The expected output of the study is a more precise estimation of the maximal hydrogen concentration admissible in ?GRTgaz' networks.

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